FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Cohn, JD Baglan, JS White, M AF Cohn, JD Baglan, JS White, M TI A comparison of simulated and analytic major merger counts SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : numerical; cosmology : theory; dark matter ID COLD DARK-MATTER; LAGRANGIAN DYNAMICAL THEORY; LARGE-SCALE STRUCTURE; N-BODY SIMULATIONS; GALAXY FORMATION; COSMIC STRUCTURES; BACKGROUND-RADIATION; HIERARCHICAL-MODELS; MASS FUNCTION; EVOLUTION AB We use large volume, high resolution, N-body simulations of three different Lambda CDM models, with different clustering strengths, to generate dark-matter halo merging histories. Over the reliable range of halo masses, roughly galaxy groups to rich clusters of galaxies, we quantify the number density of major mergers for two different time intervals and compare them with analytic predictions based on the extended Press-Schechter theory. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Mehta Res Inst, Allahabad 211019, Uttar Pradesh, India. Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. RP Cohn, JD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI White, Martin/I-3880-2015 OI White, Martin/0000-0001-9912-5070 NR 58 TC 23 Z9 23 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 11 PY 2001 VL 325 IS 3 BP 1053 EP 1064 DI 10.1046/j.1365-8711.2001.04509.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 466VG UT WOS:000170666400013 ER PT J AU Vaisanen, P Tollestrup, EV Fazio, GG AF Vaisanen, P Tollestrup, EV Fazio, GG TI Confusion limit resulting from galaxies: using the Infrared Array Camera on board SIRTF SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : observational; techniques : photometric; galaxies : evolution; galaxies : photometry; cosmology : observations; infrared : galaxies ID EXTRAGALACTIC SOURCE COUNTS; TELESCOPE-FACILITY SIRTF; HUBBLE-DEEP-FIELD; MU-M; EVOLUTION; ANISOTROPIES; LUMINOSITY; EMISSION AB Recent ISO data have allowed, for the first time, observationally based estimates for source confusion in mid-infrared surveys. We use the extragalactic source counts from ISOCAM in conjunction with K-band counts to predict the confusion resulting from galaxies in deep midinfrared observations. We specifically concentrate on the near-future Space Infrared Telescope Facility (SIRTF) mission, and calculate expected confusion for the Infrared Array Camera (IRAC) on board SIRTF. A defining scientific goal of the IRAC instrument will be the study of high-redshift galaxies using a deep, confusion-limited wide-field survey at 3-10 mum. A deep survey can reach 3-mu Jy sources with reasonable confidence in the shorter wavelength IRAC bands. Truly confusion-limited images with the 8 mum will be difficult to obtain because of practical time constraints, unless infrared galaxies exhibit very strong evolution beyond the deepest current observations. We find L* galaxies to be detectable to z = 3-3.5 at 8 mum, which is slightly more pessimistic than found in 1999 by Simpson & Eisenhardt. C1 Univ Helsinki Observ, Helsinki 00014, Finland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Vaisanen, P (reprint author), Univ Helsinki Observ, POB 14, Helsinki 00014, Finland. NR 41 TC 15 Z9 15 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 11 PY 2001 VL 325 IS 3 BP 1241 EP 1252 DI 10.1046/j.1365-8711.2001.04566.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 466VG UT WOS:000170666400031 ER PT J AU Collinge, MJ Brandt, WN Kaspi, S Crenshaw, DM Elvis, M Kraemer, SB Reynolds, CS Sambruna, RM Wills, BJ AF Collinge, MJ Brandt, WN Kaspi, S Crenshaw, DM Elvis, M Kraemer, SB Reynolds, CS Sambruna, RM Wills, BJ TI High-resolution X-ray and ultraviolet spectroscopy of the complex intrinsic absorption in NGC 4051 with Chandra and the Hubble Space Telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 4051); galaxies : nuclei; galaxies : Seyfert; ultraviolet : galaxies; X-rays : galaxies AB We present the results from simultaneous observations of the narrow-line Seyfert 1 galaxy NGC 4051 with the Chandra High Energy Transmission Grating Spectrometer and the Hubble Space Telescope Space Telescope Imaging Spectrograph. The X-ray grating spectrum reveals absorption and emission lines from hydrogen-like and helium-like ions of O, Ne, Mg, and Si. We resolve two distinct X-ray absorption systems: a high-velocity blueshifted system at -2340 +/- 130 km s(-1) and a low-velocity blue-shifted system at -600 +/- 130 km s(-1). In the UV spectrum we detect strong absorption, mainly from C IV, N V, and Si IV, that is resolved into as many as nine different intrinsic absorption systems with velocities between -650 and 30 km s(-1). Although the low-velocity X-ray absorption is consistent in velocity with many of the UV absorption systems, the high-velocity X-ray absorption seems to have no UV counterpart. In addition to the absorption and emission lines, we also observe rapid X-ray variability and a state of low X-ray flux during the last approximate to 15 ks of the observation. NGC 4051 has a soft X-ray excess that we fit in both the high and low X-ray flux states. The high-resolution X-ray spectrum directly reveals that the soft excess is not composed of narrow emission lines and that it has significant spectral curvature. A power-law model fails to fit it, while a blackbody produces a nearly acceptable fit. We compare the observed spectral variability with the results of previous studies of NGC 4051. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Colorado, JILA, Boulder, CO 80303 USA. George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA. George Mason Univ, Sch Computat Sci, Fairfax, VA 22030 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. RP Collinge, MJ (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RI Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 0 TC 101 Z9 101 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 AUG 10 PY 2001 VL 557 IS 1 BP 2 EP 17 DI 10.1086/321635 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 464XF UT WOS:000170558100002 ER PT J AU Perna, R Heyl, JS Hernquist, LE Juett, AM Chakrabarty, D AF Perna, R Heyl, JS Hernquist, LE Juett, AM Chakrabarty, D TI Anomalous X-ray pulsars and soft gamma-ray repeaters: Spectral fits and the magnetar model SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : neutron; X-rays : stars ID NEUTRON-STARS; ATMOSPHERES; RADIATION; EMISSION; ABSORPTION; ACCRETION; ENVELOPES; FIELDS; DISKS AB The energy source powering the X-ray emission from anomalous X-ray pulsars (AXPs) and soft gamma -ray repeaters (SGRs) is still uncertain. In one scenario, the presence of an ultramagnetized neutron star, or "magnetar," with B similar or equal to 10(14)-10(15) G is invoked. To investigate this hypothesis, we have analyzed archival ASCA data for several known AXPs and SGRs and fitted them with a model in which all or part of the X-ray flux originates as thermal emission from a magnetar. Our magnetar spectral model includes the effects of the anisotropy of the heat flow through an ultramagnetized neutron star envelope, reprocessing by a light-element atmosphere, and general relativistic corrections to the observed spectrum. We obtain good fits to the data with radii for the emitting areas that are generally consistent with those expected for neutron stars, in contrast to blackbody (BB) fits, which imply much smaller radii. Furthermore, the inclusion of atmospheric effects results in inferred temperatures lower than those implied by BB fits, but still too high to be accounted for by thermal cooling alone. An extra source of heating (possibly resulting from magnetic field decay) is needed. Despite the harder tail in the spectrum produced by reprocessing of the outgoing flux through the atmosphere, spectral fits still require a considerable fraction of the flux to be in a power-law component, probably produced in the magnetosphere of the star. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Perna, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 53 TC 44 Z9 44 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 AUG 10 PY 2001 VL 557 IS 1 BP 18 EP 23 DI 10.1086/321569 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 464XF UT WOS:000170558100003 ER PT J AU Croft, RAC Di Matteo, T Hernquist, L Katz, N Fardal, MA Weinberg, DH AF Croft, RAC Di Matteo, T Hernquist, L Katz, N Fardal, MA Weinberg, DH TI Hydrodynamic simulation of the cosmological X-ray background SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; diffuse radiation; large-scale structure of universe; X-rays : diffuse background ID LARGE-SCALE STRUCTURE; SUPERMASSIVE BLACK-HOLES; ROSAT DEEP SURVEY; GALAXY FORMATION; INTERGALACTIC MEDIUM; LOCKMAN FIELD; CLUSTERS; EVOLUTION; EMISSION; QUASARS AB We use a hydrodynamic simulation of an inflationary cold dark matter model with a cosmological constant to predict properties of the extragalactic X-ray background (XRB). We focus on emission from the intergalactic medium (IGM), with particular attention to diffuse emission from warm-hot gas that lies in relatively smooth filamentary structures between galaxies and galaxy clusters. We also include X-rays from point sources associated with galaxies in the simulation, and we make maps of the angular distribution of the emission. Although much of the X-ray luminous gas has a filamentary structure, the filaments are not evident in the simulated maps because of projection effects. In the soft (0.5-2 kev) band, our calculated mean intensity of radiation from intergalactic and cluster gas is 2.3 X 10(-12) ergs(-1) cm(-2) deg(-2), 35% of the total softband emission. This intensity is compatible at the similar to1 sigma level with estimates of the unresolved soft background intensity from deep ROSAT and Chandra measurements. Only 4% of the hard (2-10 keV) emission is associated with intergalactic gas. Relative to active galactic nuclei flux, the IGM component of the XRB peaks at a lower redshift (median z similar to 0.45) and spans a narrower redshift range, so its clustering makes an important contribution to the angular correlation function of the total emission. The clustering on the scales accessible to our simulation (0.'1-10') is significant, with an amplitude roughly consistent with an extrapolation of recent ROSAT results to small scales. A cross-correlation analysis of the XRB against nearby galaxies taken from a simulated redshift survey also yields a strong signal from the IGM. Our conclusions about the soft background intensity differ from those of some recent papers that have argued that the expected emission from gas in galaxy, group, and cluster halos would exceed the observed background unless much of the gas is expelled by supernova feedback. We obtain reasonable compatibility with current observations in a simulation that incorporates cooling, star formation, and only modest feedback. A clear prediction of our model is that the unresolved portion of the soft XRB will remain mostly unresolved even as observations reach deeper point-source sensitivity. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Croft, RAC (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM rcroft@cfa.harvard.edu; tdimatte@cfa.harvard.edu; lars@cfa.harvard.edu; nsk@kaka.astro.umass.edu; fardal@weka.astro.umass.edu; dhw@astronomy.ohio-state.edu RI Croft, Rupert/N-8707-2014 OI Croft, Rupert/0000-0003-0697-2583 NR 72 TC 79 Z9 79 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 AUG 10 PY 2001 VL 557 IS 1 BP 67 EP 87 DI 10.1086/321632 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 464XF UT WOS:000170558100008 ER PT J AU Bergin, EA Ciardi, DR Lada, CJ Alves, J Lada, EA AF Bergin, EA Ciardi, DR Lada, CJ Alves, J Lada, EA TI Molecular excitation and differential gas-phase depletions in the IC 5146 dark cloud SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; ISM : abundances; ISM : clouds; ISM : individual (IC 5146); ISM : molecules; stars : formation ID ROTATIONAL-EXCITATION; DUST EXTINCTION; CORE L1544; CHEMISTRY; ABSORPTION; NITROGEN; N2H+; HCO+ AB We present a combined near-infrared and molecular line study of a 25' x 8' area in the northern streamer of the IC 5146 cloud. Using the technique pioneered by Lada and coworkers, we construct a Gaussian-smoothed map of the infrared extinction with the same resolution as the molecular line observations in order to examine correlations of integrated intensities and molecular abundances with extinction for (CO)-O-17, (CS)-S-34, and N2H+. We find that over a visual extinction range of 0-40 mag, there is good evidence for the presence of differential gas-phase depletions in the densest portions of IC 5146. Both CO and CS exhibit a statistically significant (factor of similar to3) abundance reduction near A(V) similar to 12 mag, while, in direct contrast, at the highest extinctions (A(V) > 10 mag), N2H+ appears relatively undepleted. Moreover, for A(V) < 4 mag, there exists little or no N2H+. This pattern of depletions is consistent with the predictions of chemical theory. Through the use of a time- and depth-dependent chemical model, we show that the near-uniform or rising N2H+ abundance with extinction is a direct result of a reduction in its destruction rate at high extinction because of the predicted and observed depletion of CO molecules. The observed abundance threshold for N2H+, A(V)(th) similar to 4 mag, is examined in the context of this same model, and we demonstrate how this technique can be used to test the predictions of depth-dependent chemical models. Finally, we find that cloud density gradients can have a significant effect on the excitation and detectability of high dipole moment molecules, which are typically far from local thermodynamic equilibrium. Density gradients also cause chemical changes since reaction rates and depletion timescales are density-dependent. Accounting for such density/excitation gradients is crucial to a correct determination and proper interpretation of molecular abundances. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. European So Observ, D-85748 Garching, Germany. RP Bergin, EA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 36 TC 100 Z9 101 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 AUG 10 PY 2001 VL 557 IS 1 BP 209 EP 225 DI 10.1086/321625 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 464XF UT WOS:000170558100018 ER PT J AU Menou, K McClintock, JE AF Menou, K McClintock, JE TI The quiescent emission spectrum of centaurus X-4 and other X-ray transients containing neutron stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : magnetic fields; stars : neutron; X-rays : stars ID ADVECTION-DOMINATED ACCRETION; BLACK-HOLE; ASCA OBSERVATIONS; AQUILA X-1; CEN X-4; MODEL; NOVAE; LUMINOSITY; ATMOSPHERES; TRANSITIONS AB We use the observed optical-U-V and X-ray emission spectrum of Cen X-4 during quiescence to constrain models for the accretion flow in this system. We argue that the optical-UV emission is not due to an optically thick quiescent accretion disk, nor due to synchrotron emission from an advection-dominated accretion flow (ADAF). Emission from the bright spot could account for the observed optical-UV component if the mass transfer rate in Cen X-4 is greater than or similar to2 x 10(16) g s(-1). Although the presence of an ADAF around the neutron star leads to Compton upscattering of the soft X-ray photons radiated from the stellar surface, we find that this process alone cannot account for the power-law component seen in the quiescent X-ray spectrum of Cen X-4 and other X-ray transients containing neutron stars; this result is independent of whether the source of soft photons is incandescent thermal emission or accretion-powered emission. We conclude that, in models which invoke the presence of an ADAF and a propeller effect for the quiescence of X-ray transients containing neutron stars, the intrinsic emission from the ADAF must contribute very little to the optical-U-V and X-ray emission observed. If these ADAF + propeller models are correct, the X-ray power-law component observed must arise from regions where the gas impacts the neutron star surface. Variability studies could greatly help clarify the role of the various emission mechanisms involved. C1 Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Menou, K (reprint author), Princeton Univ, Dept Astrophys Sci, Peyton Hall,Ivy Lane, Princeton, NJ 08544 USA. EM kristen@astro.princeton.edu; jem@head-cfa.harvard.edu NR 58 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 J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 2001 VL 557 IS 1 BP 304 EP 310 DI 10.1086/321665 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 464XF UT WOS:000170558100027 ER PT J AU Ciaravella, A Raymond, JC Reale, F Strachan, L Peres, G AF Ciaravella, A Raymond, JC Reale, F Strachan, L Peres, G TI 1997 December 12 helical coronal mass ejection. II. Density, energy estimates, and hydrodynamics SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : coronal mass ejections (CMEs); Sun : UV radiation ID MAGNETIC-FLUX ROPE; NUMERICAL SIMULATIONS; THERMAL INSTABILITIES; STRATIFIED GASES; SOLAR CORONA; MODEL; ULTRAVIOLET; STREAMERS; SPECTROMETER; PROMINENCE AB We use Ultraviolet Coronagraph and Spectrometer (UVCS) spectra to investigate the density range of the plasma ejected during the coronal mass ejection (CME) on 1997 December 12. Time-dependent ionization states for several phenomenological models, with the boundary conditions derived from the EUV Imaging Telescope (EIT) and UVCS observations, were computed and constraints on the density and temperature of the plasma at the early stage of the ejection are obtained. The role of physical mechanisms such as thermal conduction, radiation, and heating is also studied with a two-dimensional hydrodynamics simulation. The kinetic, thermal, and gravitational energies are estimated as well as the plasma heating. Whenever the ejected plasma has a density greater than or equal to 10(9)cm(-3), a continuous supply of heat is required to meet the conditions observed at 1.7 R.. Moreover heating mechanisms that release energy gradually during the outward motion of the plasma seem to be more appropriate than those that dump most of the energy when the plasma is lower in the corona. Our simulations also indicate that a. three-dimensional self-similar expansion does not fit the UVCS observations. Comparisons with some CME models from the dynamical and energetics points of view are discussed. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron Palermo GS Vaiana, I-90134 Palermo, Italy. Dipartimento Sci Fis & Astron, I-90134 Palermo, Italy. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM aciaravella@cfa.harvard.edu OI Reale, Fabio/0000-0002-1820-4824 NR 37 TC 31 Z9 32 U1 0 U2 3 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 AUG 10 PY 2001 VL 557 IS 1 BP 351 EP 365 DI 10.1086/321662 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 464XF UT WOS:000170558100034 ER PT J AU Kalkofen, W AF Kalkofen, W TI The case against cold, dark chromospheres SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; shock waves; Sun : atmospheric motions; Sun : chromosphere; Sun : infrared; Sun : UV radiation ID TRANSFORM SPECTROMETER OBSERVATIONS; SOLAR OUTER ATMOSPHERE; CARBON-MONOXIDE; ACOUSTIC-WAVES; K-GRAINS; II H; QUIET; ENERGY; BANDS; LINES AB Is the, solar chromosphere always hot, with relatively small temperature variations (deltaT/T similar to 0.1), or is it cold most of the time, with temperature fluctuations that reach deltaT/T similar to 10 at the top of the chromosphere? Or, equivalently, is the chromosphere heated continually or only for a few seconds once every 3 minutes? Two types of empirical model, one essentially time independent and always hot, the other highly time dependent and mostly cold, come to fundamentally different conclusions. This paper analyzes the time-dependent model of the quiet, nonmagnetic chromosphere by Carlsson & Stein and shows that it predicts deep absorption lines, none of which are observed; intensity fluctuations in the Lyman continuum that are much larger than observed; and time-averaged emission that falls far short of the observed emission. The paper concludes that the solar chromosphere, while time-dependent, is never cold and dark. The same conclusion applies for stellar chromospheres. A complete, time-dependent model of the nonmagnetic chromosphere must describe two phenomena: (1) dynamics, like that modeled by Carlsson & Stein for chromospheric bright points but corrected for the geometrical properties of shocks propagating in an upward-expanding channel, and (2) the energetically more important general, sustained heating of the chromosphere, as described by current time-independent empirical models but modified in the upper photosphere for the formation of molecular absorption lines of CO in a dynamical medium. This model is always hot and, except for absorption features caused by departures from local thermodynamic equilibrium, shows chromospheric lines only in emission. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kalkofen, W (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 46 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 J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 2001 VL 557 IS 1 BP 376 EP 383 DI 10.1086/321638 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 464XF UT WOS:000170558100036 ER PT J AU Davis, JLD AF Davis, JLD TI Diel changes in habitat use by two tidepool fishes SO COPEIA LA English DT Article ID GIRELLA NIGRICANS AYRES; OLIGOCOTTUS-MACULOSUS; INTERTIDAL FISHES; MARINE FISHES; TEMPERATURE; COMPETITION; CALIFORNIA; SNYDERI; GROWTH AB I examined the effects of low-tide timing on tidepool use by two southern California fishes, Clinocottus analis and Girella nigricans. Abundance of these fishes in middle and upper intertidal pools was higher when low tides occurred at night or in the early morning (4.4-9.7 fish per pool) than in the afternoon (1.3-3.4 fish per pool). Mean fish size was also higher during nighttime low tides than daytime low tides. Tidepools higher in the intertidal zone generally displayed greater differences in fish abundance between early morning and afternoon low tides than lower pools. In addition, these upper tidepools reached higher temperatures during afternoon low tides (up to 30 C) than lower tidepools, often exceeding or nearing the preferred and lethal maximum temperatures reported for the two study species. Diel vertical habitat shifts by middle and upper tidepool fishes indicate that their partitioning of rocky intertidal habitat occurs on short-term temporal as well as spatial scales. C1 Scripps Institut Oceanog, La Jolla, CA 92093 USA. RP Davis, JLD (reprint author), Smithsonian Environm Res Ctr, POB 28 647 Contees Wharf Rd, Edgewater, MD 21037 USA. EM janalddavis@yahoo.com NR 27 TC 11 Z9 11 U1 0 U2 6 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD AUG 6 PY 2001 IS 3 BP 835 EP 841 DI 10.1643/0045-8511(2001)001[0835:DCIHUB]2.0.CO;2 PG 7 WC Zoology SC Zoology GA 516AQ UT WOS:000173529600029 ER PT J AU Pierce, S Maxwell, K Griffiths, H Winter, K AF Pierce, S Maxwell, K Griffiths, H Winter, K TI Hydrophobic trichome layers and epicuticular wax powders in Bromeliaceae SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE Bromeliaceae; epicuticular waxy; fluorographic dimensional imaging; SEM; trichomes; water repellency ID BROCCHINIA-REDUCTA; GAS-EXCHANGE; SURFACES; DROPLETS; CAM AB The distinctive foliar trichome of Bromeliaceae has promoted the evolution of an epiphytic habit in certain taxa by allowing the shoot to assume a significant role in the uptake of water and mineral nutrients. Despite the profound ecophysiological and taxonomic importance of this epidermal structure, the functions of nonabsorbent trichomes in remaining Bromeliaceae are not fully understood. The hypothesis that light reflection from these trichome layers provides photoprotection was not supported by spectroradiometry and fluorimetry in the present study; the mean reflectance of visible light from trichome layers did not exceed 6.4% on the adaxial surfaces of species representing a range of ecophysiological types nor was significant photoprotection provided by their presence. Several reports suggesting water repellency in some terrestrial Bromeliaceae were investigated. Scanning electron microscopy (SEM) and a new technique-fluorographic dimensional imaging (FDI)-were used to assess the interaction between aqueous droplets and the leaf surfaces of 86 species from 25 genera. In the majority of cases a dense layer of overlapping, stellate or peltate trichomes held water off the leaf epidermis proper. In the case of hydrophobic tank-forming tillandsioideae, a powdery epicuticular wax layer provided water repellency. The irregular architecture of these indumenta resulted in relatively little contact with water droplets. Most mesic terrestrial Pitcairnioideae examined either possessed glabrous leaf blades or hydrophobic layers of confluent trichomes on the abaxial surface. Thus, the present study indicates that an important ancestral function of the foliar trichome in Bromeliaceae was water repellency. The ecophysiological consequences of hydrophobia are discussed. C1 Smithsonian Trop Res Inst, Panama City, Panama. RP Pierce, S (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Panama City, Panama. OI Pierce, Simon/0000-0003-1182-987X NR 47 TC 45 Z9 53 U1 1 U2 14 PU BOTANICAL SOC AMER INC PI COLUMBUS PA OHIO STATE UNIV-DEPT BOTANY, 1735 NEIL AVE, COLUMBUS, OH 43210 USA SN 0002-9122 J9 AM J BOT JI Am. J. Bot. PD AUG PY 2001 VL 88 IS 8 BP 1371 EP 1389 DI 10.2307/3558444 PG 19 WC Plant Sciences SC Plant Sciences GA 461MW UT WOS:000170368900004 PM 21669669 ER PT J AU Piercey-Normore, MD Depriest, PT AF Piercey-Normore, MD Depriest, PT TI Algal switching among lichen symbioses SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE Cladonia; cospeciation; host switching; ITS rDNA; lichens; parallel cladogenesis; phylogeny; symbiosis ID BACTERIAL ENDOSYMBIONTS; PHYLOGENETIC CONGRUENCE; MOLECULAR PHYLOGENIES; COSPECIATION; COEVOLUTION; EVOLUTION; FUNGI; HOSTS; LICE; SEQUENCES AB Lichens are intimate and long-term symbioses of algae and fungi. Such intimate associations are often hypothesized to have undergone long periods of symbiotic interdependence and coevolution. However, coevolution has not been rigorously tested for lichen associations. In the present study we compared the nuclear internal transcribed spacer (ITS) phylogenies of algal and fungal partners from 33 natural lichen associations to test two aspects of coevolution, cospeciation and parallel cladogenesis. Since statistically significant incongruence between symbiont phylogenies rejected parallel cladogenesis and minimized cospeciation events, we conclude that switching of highly selected algal genotypes occurs repeatedly among these symbiotic lichen associations. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, Washington, DC 20560 USA. RP Univ Manitoba, Dept Bot, 525 Buller Bldg, Winnipeg, MB R3T 2N2, Canada. RI DePriest, Paula/K-6633-2015 NR 57 TC 132 Z9 135 U1 5 U2 35 PU BOTANICAL SOC AMER INC PI ST LOUIS PA PO BOX 299, ST LOUIS, MO 63166-0299 USA SN 0002-9122 EI 1537-2197 J9 AM J BOT JI Am. J. Bot. PD AUG PY 2001 VL 88 IS 8 BP 1490 EP 1498 DI 10.2307/3558457 PG 9 WC Plant Sciences SC Plant Sciences GA 461MW UT WOS:000170368900017 PM 21669682 ER PT J AU Koga, T Backwell, PRY Christy, JH Murai, M Kasuya, E AF Koga, T Backwell, PRY Christy, JH Murai, M Kasuya, E TI Male-biased predation of a fiddler crab SO ANIMAL BEHAVIOUR LA English DT Article ID PREY AVAILABILITY; UCA-PUGILATOR; GENUS UCA; BEHAVIOR; RISK; COURTSHIP; SYSTEMS; DEFENSE; CHOICE AB Great-tailed grackles, Quiscalus mexicanus, prey on fiddler crabs, Uca beebei, either by running straight at them or by running past them then angling sharply back to strike. Grackles that used angled runs caught only males and were twice as successful as birds that used straight runs and caught equal numbers of males and females. Why do grackles that use angled runs catch only males? Males were not differentially available, nor did grackles prefer them to females in choice tests. Fewer crabs entered their burrows when we moved a model predator past them than when we moved it directly towards them and crabs allowed the model to get closer when it passed then returned to strike. Although crabs may take more risks when birds use angled runs, the sexes did not differ in their escape responses. Hence, differential risk taking cannot explain male-biased predation by birds using angled runs. We suggest that males, with their large claws and lighter colours, are more conspicuous than cryptic females. When a bird runs past then turns to dash back at a crab it may be able to keep track of a male much better than a female. Indeed, grackles missed all females they struck at using angled runs. Hence, males may be conspicuous and preferred prey to birds using angled runs. Males' enlarged claws, bright colours and other sexually selected traits may increase male predation rate in this context. (C) 2001 The Association for the Study of Animal Behaviour. C1 Wakayama Univ, Fac Educ, Wakayama 6408501, Japan. Smithsonian Trop Res Inst, Unit 0948, Miami, FL 34002 USA. Univ Ryukyus, Sesoko Stn, Trop Biosphere Res Ctr, Okinawa 9050227, Japan. Kyushu Univ, Fac Sci, Dept Biol, Fukuoka 8128581, Japan. RP Koga, T (reprint author), Wakayama Univ, Fac Educ, Wakayama 6408501, Japan. RI U-ID, Kyushu/C-5291-2016; Backwell, Patricia/C-8883-2009 NR 17 TC 60 Z9 62 U1 0 U2 14 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0003-3472 J9 ANIM BEHAV JI Anim. Behav. PD AUG PY 2001 VL 62 BP 201 EP 207 DI 10.1006/anbe.2001.1740 PN 2 PG 7 WC Behavioral Sciences; Zoology SC Behavioral Sciences; Zoology GA 474DA UT WOS:000171088000002 ER PT J AU Garcia-Heras, M Blackman, MJ Fernandez-Ruiz, R Bishop, RL AF Garcia-Heras, M Blackman, MJ Fernandez-Ruiz, R Bishop, RL TI Assessing ceramic compositional data: A comparison of total reflection x-ray fluorescence and instrumental neutron activation analysis on Late Iron Age Spanish Celtiberian ceramics SO ARCHAEOMETRY LA English DT Article DE central Spain; Late Iron Age; Celtiberian Period; total reflection x-ray fluorescence; instrumental neutron activation; intercomparison; ceramic compositional analysis; provenance ID ARCHAEOLOGICAL CERAMICS; PROVENANCE; POTTERY; PRECISION; TXRF AB A solid-phase, non-chemical processing protocol was recently developed as a means of chemically characterizing archaeological ceramics by total reflection x-ray fluorescence (TRXF). Following this methodology, TXRF can provide semi-quantitative determinations for 18 elements with comparable levels of precision and accuracy for the majority of them in comparison with a clay reference material analysed by instrumental neutron activation (INAA). In order critically to assess the analytical capabilities of TXRF, a large sample set of Late Iron Age Spanish Celtiberian ceramics and modern clays was analysed both by TXRF and INAA. Semi-quantitative chemical data provided by TXRF and quantitative data provided by INAA were subjected to commonly used multivariate statistical methods as a way of evaluating the ability of the new technique to discriminate among different compositional groups. The comparison of the two data sets shows no significant discrepancies, thereby allowing support for the same archaeological interpretation. These results suggest that TXRF has potential applicability for compositional characterization of archaeological ceramics providing data that are useful for provenance studies. C1 Smithsonian Ctr Materials Res & Educ, Suitland, MD 20746 USA. Univ Autonoma Madrid, Fac Ciencias, E-28049 Madrid, Spain. RP Garcia-Heras, M (reprint author), Smithsonian Ctr Materials Res & Educ, 4210 Silver Hill Rd, Suitland, MD 20746 USA. RI Fernandez-Ruiz, R/B-5218-2008; Garcia-Heras, Manuel/G-8803-2015 NR 31 TC 12 Z9 13 U1 1 U2 7 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0003-813X EI 1475-4754 J9 ARCHAEOMETRY JI Archaeometry PD AUG PY 2001 VL 43 BP 325 EP 347 DI 10.1111/1475-4754.00020 PN 3 PG 23 WC Archaeology; Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Geosciences, Multidisciplinary SC Archaeology; Chemistry; Geology GA 464TV UT WOS:000170548600002 ER PT J AU Brown, WR Geller, MJ Fabricant, DG Kurtz, MJ AF Brown, WR Geller, MJ Fabricant, DG Kurtz, MJ TI V- and R-band galaxy luminosity functions and low surface brightness galaxies in the Century Survey SO ASTRONOMICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : fundamental parameters; galaxies : luminosity function, mass function; galaxies : photometry; large-scale structure of universe ID CAMPANAS REDSHIFT SURVEY; FIELD CCD SURVEY; NEARBY GALAXIES; MOSAIC IMAGER; CLUSTER; MAGNITUDE; EVOLUTION; DENSITY; CATALOG; VELOCITIES AB We use 64 deg(2) of deep V and R CCD images to measure the local V- and R-band luminosity functions of galaxies. The V-o < 16.7 and R-o < 16.2 redshift samples contain 1255 and 1251 galaxies and are 98.1% and 98.2% complete, respectively. We apply k-corrections before the magnitude selection so that the completeness is to the same depth for all spectral types. The V and R faint-end slopes are surprisingly identical : alpha = -1.07 +/- 0.09. Representative Schechter function parameters for H-o = 100 are : M-R* = -20.88 +/- 0.09, phi (R)* = 0.016 +/- 0.003 Mpc(-3) and M-V* = -20.23 +/- 0.09, phi (V)* = 0.020 +/- 0.003 Mpc(-3). The V and R local luminosity densities, j(R) = (1.9 +/- 0.6) x 10(8) L-. and j(v) = (2.2 +/- 0.7) x 10(8) L-., are in essential agreement with the recent 2 Degree Field Galaxy Redshift Survey and Sloan Digital Sky Survey determinations. All low surface brightness (LSB) galaxies fall in the large-scale structure delineated by high surface brightness galaxies. The properties and surface number density of our LSB galaxies are consistent with the LSB galaxy catalog of O'Neil, Bothun & Cornell, suggesting that our samples are complete for LSB galaxies to the magnitude limits. We measure colors, surface brightnesses, and luminosities for our samples, and find strong correlations among these galaxy properties. The color-surface brightness relation is (V-R)(o) = (-0.11 +/- 0.05)mu (R), (o) + (2.6 +/- 0.9). C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Brown, WR (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI KURTZ, Michael /B-3890-2009; OI Kurtz, Michael/0000-0002-6949-0090 NR 57 TC 38 Z9 38 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 AUG PY 2001 VL 122 IS 2 BP 714 EP 728 DI 10.1086/321176 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462PQ UT WOS:000170429300015 ER PT J AU Crosthwaite, LP Turner, JL Hurt, RL Levine, DA Martin, RN Ho, PTP AF Crosthwaite, LP Turner, JL Hurt, RL Levine, DA Martin, RN Ho, PTP TI CO and neutral gas in the disk of the spiral galaxy IC 342 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (IC 342); galaxies : ISM; galaxies : spiral; galaxies : structure; ISM : molecules ID CO-TO-H-2 CONVERSION FACTOR; MOLECULAR GAS; STAR-FORMATION; IC 342; MILKY-WAY; PHOTODISSOCIATION REGIONS; RADIAL-DISTRIBUTION; INTERSTELLAR-MEDIUM; ARRAY OBSERVATIONS; APERTURE SYNTHESIS AB We present "on-the-fly," fully sampled maps of CO(1-0) in the central 15' of the spiral galaxy IC 342. In addition to the bright CO nuclear peak, there is a prominent CO 2'x5' bar and an extensive CO disk. The bar and nucleus contain 30% of the total observed CO emission in IC 342. Beyond the bar the CO disk contains two spiral arms, which coincide with the two inner optical arms. The substantial inter-arm CO component within this inner region has a mean surface density of 8 M(.) pc(-2), close to the mean surface density of 10 M(.) pc(-2), that extends to a radius of 7' (4 kpc). The total inferred H(2) mass is 7 x 10(8) M(.) which is 30% of the total H I mass. We combine the CO data with VLA H I maps to obtain a map of the total gas surface density (Sigma (HI) + Sigma (H2)) in IC 342. The gas surface density shows a centrally peaked disk, dominated by H(2) to a radius of 5' (3 kpc). Spiral arms run continuously from the inner to outer galaxy, transitioning smoothly from predominantly molecular in the inner galaxy to predominantly atomic at large radii. On a global scale, the gas surface density is spatially correlated with optical spiral arm structure. On 1' (600 pc) scales the disk displays bar and arm asymmetries, azimuthal displacements of CO and H I emission, and structure that becomes increasingly complex with increasing galactic radii. We find an excellent correlation between 21 cm radio continuum and the total gas surface density. C1 Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Acad Sinica, Inst Astron & Astrophys, Taipei 115, Taiwan. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Crosthwaite, LP (reprint author), Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. EM lucian@astro.ucla.edu; turner@astro.ucla.edu; hurt@ipac.caltech.edu; deblev@ipac.caltech.edu; rmartin@cfa.harvard.edu; pho@cfa.harvard.edu NR 88 TC 34 Z9 34 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 2001 VL 122 IS 2 BP 797 EP 814 DI 10.1086/321148 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462PQ UT WOS:000170429300020 ER PT J AU Danforth, CW Blair, WP Raymond, JC AF Danforth, CW Blair, WP Raymond, JC TI A detailed analysis of a Cygnus Loop shock-cloud interaction SO ASTRONOMICAL JOURNAL LA English DT Article DE planetary nebulae : general; supernova remnants ID HOPKINS-ULTRAVIOLET-TELESCOPE; X-RAY; SUPERNOVA REMNANT; INTERSTELLAR CLOUDS; IMAGING TELESCOPE; FE-X; EMISSION; WAVE; FILAMENT AB The XA region of the Cygnus Loop is a complex zone of radiative and nonradiatve shocks interacting with interstellar clouds. We combine five far ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT), a grid of 24 IUE spectra, and a high-resolution long-slit H alpha spectrum to study the spatial emission line variations across the region. These spectral data are placed in context using ground-based optical emission-line images of the region and a far-UV image obtained by the Ultraviolet Imaging Telescope (UIT). The presence of high-ionization species (O VI, N V, and C IV) indicates a shock velocity near 170 km s(-1) while other diagnostics indicate km s(-1). It is likely that a large range v(sh) approximate to 140 of shock velocities may exist at a spatial scale smaller than we are able to resolve. By comparing C IV lambda 1550, C III lambda 977, and C III] lambda 1909, we explore resonance scattering across the region. We find that a significant column depth is present at all positions, including those not near bright optical or UV filaments. Analysis of the O VI doublet ratio suggests an average optical depth of about unity in that ion, while flux measurements of [Si VIII] lambda 1443 suggest a hot component in the region at just below 10(6) K. Given the brightness of the O VI emission and the age of the interaction, we rule out the mixing-layer interpretation of the UV emission. Furthermore, we formulate a picture of the XA region as that of an encounter of the blast wave with a finger of dense gas protruding inward from the pre-supernova cavity. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Danforth, CW (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 39 TC 24 Z9 24 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 2001 VL 122 IS 2 BP 938 EP 953 DI 10.1086/321161 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462PQ UT WOS:000170429300033 ER PT J AU Ray, A Petre, R Schlegel, EM AF Ray, A Petre, R Schlegel, EM TI Chandra and ASCA X-ray observations of the type II-L supernova SN1979C in NGC 4321 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 4321); supernovae : general; supernovae : individual (SN 1979C) ID NOVA 1979C; SN 1979C; RADIO SUPERNOVAE; VIRGO CLUSTER; EMISSION; M100; DISTANCE; OUTBURST; SN-1979C; REGION AB We report on the X-ray observation of the radio-selected supernova SN 1979C carried out with ASCA in 1997 December and serendipitously available from a Chandra Guaranteed Time Observation in 1999 November. The supernova, of type SN II-linear (SN II-L), was first observed in the optical and occurred in the weakly barred, almost face-on spiral galaxy NGC 4321 (M100). The galaxy, a member of the Virgo S Cluster, is at a distance of 17.1 Mpc and contains at least three other supernovae discovered in this century. The useful exposure time was similar to 25 ks for the Solid-State Imaging Spectrometer (SIS), similar to 28 ks for the Gas Scintillation Imaging Spectrometer, and similar to2.5 ks for the Chandra Advanced CCD Imaging Spectrometer. No point source was detected at the radio position of SN 1979C in a 3' diameter, half-power response circle in the ASCA data. The background- and galaxy-subtracted supernova (SN) signal had a 3 sigma upper limit to the flux of 6.3 x 10(-14) ergs cm(-2) s(-1) in the full ASCA SIS band (0.4-10.0 keV) and a 3 sigma upper limit of less than (3-4) x 10(-14) erg cm(-2) s(-1) in the 2-10 keV band. In the Chandra data, a source at the position of SN 1979C is marginally detected at energies below 2 keV at a flux consistent with the ROSAT HRI detection in 1995. At energies above 2 keV, no source is detected with an upper limit of similar to3 x 10(-14) ergs cm(-2) s(-1). These measurements give the first ever X-ray flux limit of a Type II-L SN above 2 keV, which is an important diagnostic of the outgoing shock wave plowing through the circumstellar medium. C1 Tata Inst Fundamental Res, Mumbai 400005, India. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Aspen Ctr Phys, Aspen, CO USA. RP Ray, A (reprint author), Tata Inst Fundamental Res, Homi Bhabha Rd, Mumbai 400005, India. NR 36 TC 7 Z9 7 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 2001 VL 122 IS 2 BP 966 EP 970 DI 10.1086/321172 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462PQ UT WOS:000170429300035 ER PT J AU Steffen, AT Mathieu, RD Lattanzi, MG Latham, DW Mazeh, T Prato, L Simon, M Zinnecker, H Loreggia, D AF Steffen, AT Mathieu, RD Lattanzi, MG Latham, DW Mazeh, T Prato, L Simon, M Zinnecker, H Loreggia, D TI A dynamical mass constraint for pre-main-sequence evolutionary tracks: The binary NTT 045251+3016 SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : spectroscopic; binaries : visual; stars : evolution; stars : pre-main-sequence ID STELLAR TURBULENT CONVECTION; HUBBLE-SPACE-TELESCOPE; T-TAURI STARS; RADIAL-VELOCITIES; OPACITIES; MODELS AB We present an astrometric-spectroscopic orbital solution for the pre-main-sequence binary NTT 045251 + 3016. Interferometric observations with the HST Fine Guidance Sensor No. 3 allowed stellar separations as small as 14 mas to be measured. Optical spectra provided 58 radial velocity measurements of the primary star, and near-infrared spectra provided two radial velocity measurements of both the primary and secondary, giving a mass ratio for the binary system. The combination of these data allows the dynamical masses and the distance of the stars to be derived. Our measurements for the primary and secondary masses are 1.45 +/- 0.19 and 0.81 +/- 0.09 respectively, and 145 +/- 8 pc for the distance of the system, consistent with prior estimates for the Taurus-Auriga star-forming region. The evolutionary tracks of D'Antona & Mazzitelli, published in 1997, Baraffe et al., published in 1998, and Palla & Stahler, published in 1999, are tested against these dynamical mass measurements. Because of the intrinsic color-T-eff variation within the K5 spectral class, each pre-main-sequence model provides a mass range for the primary. The theoretical mass range derived from the Baraffe et al. tracks that use a mixing-length parameter of alpha = 1.0 is closest to our measured primary mass, deviating between 1.3 and 1.6 sigma. The set of Baraffe et al. tracks that use alpha = 1.9 deviates between 1.6 and 2.1 sigma from our measured primary mass. The mass range given by the Palla & Stahler tracks for the primary star deviate between 1.6 and 2.9 sigma. The D'Antona & Mazzitelli tracks give a mass range that deviates by at least 3.0 sigma from our derived primary mass, strongly suggesting that these tracks are inconsistent with our observation. Observations of the secondary are less constraining than those of the primary, but the deviations between the dynamical mass of the secondary and the mass inferred for the secondary from the various pre-main-sequence tracks mirror the deviations of the primary star. All the pre-main-sequence tracks are consistent with coevality of the components of NTT 045251 + 3016. C1 Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Osserv Astron Torino, I-10025 Pino Torinese, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Inst Astrophys, D-14482 Potsdam, Germany. RP Steffen, AT (reprint author), Univ Wisconsin, Dept Astron, 475 N Charter St, Madison, WI 53706 USA. OI Lattanzi, Mario Gilberto/0000-0003-0429-7748 NR 33 TC 63 Z9 64 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 AUG PY 2001 VL 122 IS 2 BP 997 EP 1006 DI 10.1086/321155 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462PQ UT WOS:000170429300039 ER PT J AU Gladman, B Kavelaars, JJ Petit, JM Morbidelli, A Holman, MJ Loredo, T AF Gladman, B Kavelaars, JJ Petit, JM Morbidelli, A Holman, MJ Loredo, T TI The structure of the Kuiper Belt: Size distribution and radial extent SO ASTRONOMICAL JOURNAL LA English DT Article DE comets : general; Kuiper belt ID OUTER SOLAR-SYSTEM; TRANS-NEPTUNIAN OBJECTS; JUPITER-FAMILY COMETS; SHORT-PERIOD COMETS; SCATTERED PLANETESIMALS; CHAOTIC MOTION; CCD SURVEY; URANUS; DISK; ACCRETION AB The size distribution in the Kuiper Belt records physical processes operating during the formation and subsequent evolution of the solar system. This paper reports a study of the apparent magnitude distribution of faint objects in the Kuiper Belt, obtained via deep imaging on the Canada-France-Hawaii Telescope and the ESO Very Large Telescope UT1. We find that the entire range of observed objects (magnitudes m(R) similar to 20-27) is well represented by an unbroken power law, with the number of objects per square degree brighter than magnitude R being of the form Sigma (m(R) < R) = 10((R-R0)), with alpha = 0.69 and R-0 = 23.5. This luminosity function's slope implies a steep size distribution in the observed range, which should "roll over" to a shallower "collisional" slope once observations extend to even fainter magnitudes and thus sample bodies whose collisional ages become less than the age of the solar system. Our observations indicate the roll over is for diameters of less than 50 km, in agreement with collisional models. Modeling our survey gives a belt mass between 30 and 50 AU of order 0.1 M+, relatively insensitive to the roll over diameter as long as the latter is greater than or similar to1 km. We report the discovery of several objects outside of 48 AU and discuss the evidence for a sharp outer edge to the trans-Neptunian distribution. C1 Observ Cote Azur, Dept Cassini, F-06304 Nice 4, France. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Gladman, B (reprint author), Observ Cote Azur, Dept Cassini, BP 4229, F-06304 Nice 4, France. NR 75 TC 135 Z9 136 U1 1 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 AUG PY 2001 VL 122 IS 2 BP 1051 EP 1066 DI 10.1086/322080 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462PQ UT WOS:000170429300043 ER PT J AU Covino, E Melo, C Alcala, JM Torres, G Fernandez, M Frasca, A Paladino, R AF Covino, E Melo, C Alcala, JM Torres, G Fernandez, M Frasca, A Paladino, R TI New low-mass pre-main sequence spectroscopic binaries in Orion SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : binaries : spectroscopic; stars : pre-main sequence; stars : low-mass, brown dwarfs; stars : fundamental parameters ID STAR-FORMING REGION; ALL-SKY SURVEY; T-TAURI STARS; LITHIUM ABUNDANCES; RADIAL-VELOCITIES; CLUSTER; WEAK; SPECTROGRAPH; TODCOR AB We report the results of a high-resolution spectroscopic monitoring campaign on low-mass pre-main sequence spectroscopic binaries, discovered recently in the general direction of the Orion star-forming region, based on ROSAT all-sky survey X-ray observations. Also included in the present study are two binaries recognized in the course of optical follow-up observations of X-ray sources in a selected sky strip crossing the Orion SFR perpendicular to the galactic plane. Orbital elements for the six double-lined spectroscopic binaries are derived from the analysis of the radial velocities of the components. The orbital periods span from 3 to 47 days. In addition, through a matching of the binary composite spectrum with synthetic binary spectra, we estimate spectral types and luminosity ratios for the components and derive lithium abundances for individual binary components. Using the estimated stellar parameters combined with kinematical information and lithium abundance determinations, we examine the evolutionary status of the objects. We then use the minimum masses derived from the solution of the spectroscopic orbits for the systems of confirmed PMS nature to make comparisons with current theoretical pre-main sequence evolutionary tracks, and attempt to set constraints on some of the most frequently used models. C1 Osserv Astron Capodimonte, I-80131 Naples, Italy. Observ Geneva, CH-1290 Sauverny, Switzerland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Inst Astrofis Andalucia, E-18080 Granada, Spain. Osserv Astrofis Catania, I-95125 Catania, Italy. RP Covino, E (reprint author), Osserv Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy. EM covino@na.astro.it RI Melo, Claudio/O-2797-2013; OI Melo, Claudio/0000-0002-6090-8446; Alcala, Juan Manuel/0000-0001-8657-095X; Frasca, Antonio/0000-0002-0474-0896; Covino, Elvira/0000-0002-6187-6685 NR 44 TC 40 Z9 40 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 2001 VL 375 IS 1 BP 130 EP 144 DI 10.1051/0004-6361:20010842 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458VK UT WOS:000170216000017 ER PT J AU Christlieb, N Green, PJ Wisotzki, L Reimers, D AF Christlieb, N Green, PJ Wisotzki, L Reimers, D TI The stellar content of the Hamburg/ESO survey - II. A large, homogeneously-selected sample of high latitude carbon stars SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : carbon; surveys; Galaxy : halo ID WHITE-DWARF COMPANION; METAL-POOR STARS; GALACTIC HALO; BRIGHT QSOS; APM SURVEY; SPECTRA; OBJECTS; SEARCH AB We present a sample of 403 faint high latitude carbon (FHLC) stars selected from the digitized objective prism plates of the Hamburg/ESO Survey (HES). Because of the similar to 15 Angstrom spectral resolution and high signal-to-noise ratio of the HES prism spectra, our automated procedure based on the detection of C-2 and CN molecular bands permits high-confidence identification of carbon stars without the need for follow-up spectroscopy. From a set of 329 plates (87% of the survey), covering 6 400 deg(2) to a magnitude limit of V similar to 16.5, we analyze the selection efficiency and effective surface area of the HES FHLC survey to date. The surface density of FHLC stars that we detect (0.072 +/- 0.005 deg(-2)) is 2-4 times higher than that of previous objective prism and CCD surveys at high galactic latitude, even though those surveys claimed a limiting magnitude up to 1.5 magnitudes fainter. This attests to the highest selection sensitivity yet achieved for these types of stars. C1 Univ Hamburg, Hamburger Sternwarte, D-21029 Hamburg, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02140 USA. Univ Potsdam, Inst Phys, D-14469 Potsdam, Germany. RP Christlieb, N (reprint author), Univ Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg, Germany. EM nchristlieb@hs.uni-hamburg.de; pgreen@cfa.harvard.edu; lutz@astro.physik.uni-potsdam.de; dreimers@hs.uni-hamburg.de NR 31 TC 96 Z9 97 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 2001 VL 375 IS 2 BP 366 EP 374 DI 10.1051/0004-6361:20010814 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458VL UT WOS:000170216100006 ER PT J AU Gredel, R Black, JH Yan, M AF Gredel, R Black, JH Yan, M TI Interstellar C-2 and CN toward the Cyg OB2 association - A case study of X-ray induced chemistry SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : abundances; ISM : clouds; ISM : molecules; X-rays : general ID OSCILLATOR-STRENGTHS; ABSORPTION-LINES; MOLECULAR CLOUDS; PHILLIPS SYSTEM; MILKY-WAY; H-3(+); STARS; SPACE; BANDS; GAS AB An analysis of deep optical echelle spectra towards six stars in the Cyg OB2 (VI Cygni) association is presented. Interstellar absorption lines up to J " = 18 in the (2,0) and (3,0) bands of the C-2 A(1)II(u) -X(1)Sigma (+)(g) system are detected towards Cyg OB2 No. 12. The large number of rotational lines accurately constrains the gas-kinetic temperature T and the density n to T = 35 K and n = (600 +/- 100) cm(-3). The inferred C-2 column density is N(C-2) = (20(-2)(+4)) 10(13) cm(-2). The detection of various lines in the (1,0) and (2,0) band of the CN A(2)II(u) -X(2)Sigma (+) red system suggest a column density of N(CN) = (8-13) x 10(13) cm(-2). C-2 absorption lines are also detected towards Cyg OB2 No. 5 and No. 9. Inferred parameters are T = 50K, n = (600 +/- 200) cm(-3), N(C-2) = (10(-1.5)(+3.5)) x 10(13) cm(-2) towards No. 5, and T = 100 K, n greater than or equal to 800 cm(-3), N(C-2) =(5.2 +/-1) x 10(13) cm(-2) towards No. 9. Marginal detections of C-2 towards Cyg OB2 No. 8A indicate N(C-2) approximate to 3.3 x 10(13) cm(-2) and T approximate to 100 K. Upper limits are N(C-2) less than or equal to 3.3 x 10(13) cm(-2) toward Cyg OB2 No. 7 and No. 11. The C-2 observations eliminate the possibility that the molecular material along the line of sight towards Cyg OB2 No. 12 is spread over a pathlength of several hundred parsecs of very low density n approximate to 10 cm(-3). The observations provide some support to a recent chemical model which assumes a nested structure of the molecular gas. Alternatively, the C2 and CN abundances obtained towards Cyg OB2 No. 12 are in agreement with the predictions of an X-ray induced chemistry driven by an ionisation rate of zeta = (0.6-3) x 10(-15) s(-1). Calculated equilibrium temperatures of T = 25-50 K agree with temperatures inferred from C-2. The model also reproduces the observed column densities of CO and CH, and that of H-3(+) to within a factor of two. We predict a H2O+ column density of 2 x 10(12) cm(-2) towards Cyg OB2 No. 12 and H2O+ absorption lines which are detectable by optical absorption line techniques. We report the detection of interstellar Rubidium towards Cyg OB2 No. 12 and No. 5. Inferred column densities are N(Rb) = (13 +/-2) x 10(9) cm(-2) towards No. 12 and N(Rb) = (13 +/-2) x 10(9) cm(-2) towards No. 5. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Chalmers Univ Technol, Onsala Space Observ, S-43992 Onsala, Sweden. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Gredel, R (reprint author), Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany. EM gredel@caha.es; jblack@oso.chalmers.se NR 47 TC 31 Z9 31 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 2001 VL 375 IS 2 BP 553 EP 565 DI 10.1051/0004-6361:20010769 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458VL UT WOS:000170216100023 ER PT J AU Naef, D Latham, DW Mayor, M Mazeh, T Beuzit, JL Drukier, GA Perrier-Bellet, C Queloz, D Sivan, JP Torres, G Udry, S Zucker, S AF Naef, D Latham, DW Mayor, M Mazeh, T Beuzit, JL Drukier, GA Perrier-Bellet, C Queloz, D Sivan, JP Torres, G Udry, S Zucker, S TI HD80606 b, a planet on an extremely elongated orbit SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE techniques : radial velocities; stars : individuals : HD 80606; stars : individuals : HD 80607; binaries : visual; extrasolar planets ID LOW-MASS COMPANIONS; RADIAL-VELOCITIES; STARS; ECCENTRICITY; BINARY; ORIGIN; PLEIADES; SYSTEM AB We report the detection of a planetary companion orbiting the solar-type star HD80606, the brighter component of a wide binary with a projected separation of about 2000 AU. Using high-signal spectroscopic observations of the two components of the visual binary, we show that they are nearly identical. The planet has an orbital period of 111.8 days and a minimum mass of 3.9 M-Jup. With e = 0.927, this planet has the highest orbital eccentricity among the extrasolar planets detected so far. We finally list several processes this extreme eccentricity could result from. C1 Observ Geneva, CH-1290 Sauverny, Switzerland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ Grenoble 1, Observ Grenoble, Astrophys Lab, F-38041 Grenoble, France. Observ Haute Provence, F-04870 St Michel, France. RP Naef, D (reprint author), Observ Geneva, 51 Ch Maillettes, CH-1290 Sauverny, Switzerland. EM dominique.naef@obs.unige.ch NR 37 TC 121 Z9 122 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 2001 VL 375 IS 2 BP L27 EP L30 DI 10.1051/0004-6361:20010853 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458VL UT WOS:000170216100002 ER PT J AU Tieftrunk, AR Jacobs, K Martin, CL Siebertz, O Stark, AA Stutzki, J Walker, CK Wright, GA AF Tieftrunk, AR Jacobs, K Martin, CL Siebertz, O Stark, AA Stutzki, J Walker, CK Wright, GA TI (CI)-C-13 in high-mass star-forming clouds SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : abundances; atoms; clouds; HII regions; submillimeter ID C-12/C-13 ISOTOPE RATIO; H-II REGIONS; MOLECULAR CLOUDS; PHOTODISSOCIATION REGIONS; SOUTHERN-HEMISPHERE; INTERSTELLAR-MEDIUM; NGC-6334; EMISSION; GLOBULES; C-13 AB We report measurements of the C-12/C-13 abundance ratio in the three galactic regions G 333.0-0.4, NGC 6334 A and G 351.6-1.3 from observations of the (CI)-C-12 P-3(2) --> P-3(1) transition and the hyperfine components of the corresponding (CI)-C-13 transition near 809 GHz. These transitions were observed simultaneously with the CO 7-6 line emission at 806 GHz with the AST/RO telescope located at the South Pole. From a simultaneous fit to the (CI)-C-12 P-3(2) --> P-3(1) transition and the HF components of the corresponding (CI)-C-13 transition and an independent estimate of an upper limit to the optical depth of the (CI)-C-12 emission we determine intrinsic (CI)-C-12/(CI)-C-13 column density ratios of 23 +/- 1 for G 333.0-0.4, 56 +/- 14 for NGC 6334 A and 69 +/- 12 for G 351.6-1.3. As the regions observed are photon dominated, we argue that the apparent enhancement in the abundance of C-13 towards G 333.0-0.4 may be due to strong isotope-selective photodissociation of (CO)-C-13, outweighing the effects of chemical isotopic fractionation as suggested by models of PDRs. Towards NGC 6334 A and G 351.6-1.3 these effects appear to be balanced, similar to the situation for the Orion Bar region observed by Keene et al. (1998). C1 Univ Cologne, Inst Phys 1, KOSMA, D-50937 Cologne, Germany. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Bell Labs, Holmdel, NJ 07733 USA. RP Tieftrunk, AR (reprint author), Univ Cologne, Inst Phys 1, KOSMA, Zulpicher Str 77, D-50937 Cologne, Germany. EM atieftru@ph1.uni-koeln.de NR 26 TC 4 Z9 4 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 2001 VL 375 IS 2 BP L23 EP L26 DI 10.1051/0004-6361:20010939 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458VL UT WOS:000170216100001 ER PT J AU David, LP Nulsen, PEJ McNamara, BR Forman, W Jones, C Ponman, T Robertson, B Wise, M AF David, LP Nulsen, PEJ McNamara, BR Forman, W Jones, C Ponman, T Robertson, B Wise, M TI A high-resolution study of the Hydra A cluster with Chandra: Comparison of the core mass distribution with theoretical predictions and evidence for feedback in the cooling flow SO ASTROPHYSICAL JOURNAL LA English DT Article DE cooling flows; galaxies : clusters : individual (Hydra A); intergalactic medium; X-rays : galaxies ID X-RAY-CLUSTERS; EARLY-TYPE GALAXIES; DARK-MATTER HALOS; A CLUSTER; INTRACLUSTER MEDIUM; LUMINOUS CLUSTERS; DENSITY PROFILE; STAR-FORMATION; GAS; ABUNDANCES AB The cooling flow cluster Hydra A was observed during the orbital activation and the Chandra Observatory. While the X-ray image of the cluster exhibits complex structure in the central region as reported in McNamara et al., the large-scale X-ray morphology of the cluster is fairly smooth. A spectroscopic analysis of the ACIS data shows that the gas temperature in Hydra A increases outward, reaches a maximum temperature of 4 keV at 200 kpc, and then decreases slightly at larger radii. The, distribution of heavy elements is nonuniform, with a factor of 2 increase in the Fe and Si abundances within the central 100 kpc. Beyond the central 100 kpc the Si-to-Fe abundance ratio is twice solar, while the Si-to-Fe ratio of the central excess is consistent with the solar value. One of the more surprising results is the lack of spectroscopic evidence for multiphase gas within the bulk of the cooling flow. Beyond the central 30 kpc, the ACIS spectra are adequately fitted with a single-temperature model. The addition of a cooling flow component does not significantly improve the fit. Only within the central 30 kpc (where the cooling time is less than 1 Gyr) is there spectroscopic evidence for multiphase gas. However, the spectroscopic mass deposition rate is more than a factor of 10 less than the morphologically derived mass accretion rate at 30 kpc. We propose that the cooling flow region is convectively unstable owing to heating by the central radio source, which significantly reduces the net accretion rate. In addition, we show that the mass distribution within the central 30-200 kpc region scales as rho (d) proportional to r(-1.3), intermediate between an NFW and a Moore proffle, but with a best-fit NFW concentration parameter (c(NFW) = 12) approximately 3 times greater than that found in numerical simulations. However, given the limited photon statistics, we cannot rule out the presence of a flat-density core with a core radius less than 30 kpc. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Wollongong, Dept Engn Phys, Wollongong, NSW 2522, Australia. Ohio Univ, Dept Phys & Astron, Athens, OH 45701 USA. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Univ Washington, Dept Astron, Seattle, WA 98195 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP David, LP (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Forman, William/0000-0002-9478-1682 NR 61 TC 241 Z9 241 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 AUG PY 2001 VL 557 IS 2 BP 546 EP 559 DI 10.1086/322250 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 467LN UT WOS:000170704800006 ER PT J AU Finn, RA Impey, CD Hooper, EJ AF Finn, RA Impey, CD Hooper, EJ TI WFPC2 imaging of quasar environments: A comparison of Large Bright Quasar Survey and Hubble Space Telescope Archive quasars SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : interactions; quasars : general ID ACTIVE GALACTIC NUCLEI; INTERMEDIATE-REDSHIFT QUASARS; OPTICAL LUMINOSITY FUNCTION; RADIO-QUIET QUASARS; MEDIUM DEEP SURVEY; HOST GALAXIES; RICH ENVIRONMENTS; PLANETARY CAMERA; FAINT GALAXIES; LOUD QUASARS AB We present Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) data on the large-scale environments of 16 0.39 < z < 0.51 quasars from the Large Bright Quasar Survey (LBQS). The LBQS quasars are representative of the radio-quiet population, and this is one of the first looks at their large-scale environments. We, compare the LBQS environments with the environments of 27 0.15 < z < 0.55 quasars selected from the HST archive. The majority of the Archive quasars are from the PG and PKS surveys, and these quasars are more luminous on average than the LBQS. By comparing the LBQS and Archive environments, we investigate whether previous quasar environment studies have been biased as a result of studying unusually radio or optically luminous quasars. We compare observed galaxy number counts with expected counts predicted from the CNOC2 field galaxy luminosity function in order to look for statistical excesses of galaxies around the quasars. We detect a significant excess around the Archive quasars but find no such excess around the LBQS quasars. We calculate the amplitude of the spatial correlation function and find that the LBQS environments are consistent with that of the typical galaxy while the Archive, environments are slightly less rich than Abell 0 clusters. We find no difference between the environments of radio-loud and radio-quiet quasars in either sample. However, comparison with previously published work shows that the LBQS radio-loud quasars are in sparse environments when compared with other radio-loud quasars, and the Archive radio-quiet quasars are in dense environments compared to other radio-quiet quasars. The richer environments of the Archive radio-quiet quasars cannot be explained by their higher optical luminosities. We find a positive correlation (95%) between radio luminosity and environment for the radio-loud quasars. This may explain why the LBQS radio-loud quasars, which are less radio luminous, are in sparser environments. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Finn, RA (reprint author), Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA. NR 57 TC 13 Z9 13 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 AUG PY 2001 VL 557 IS 2 BP 578 EP 593 DI 10.1086/321603 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 467LN UT WOS:000170704800009 ER PT J AU Rusin, D Kochanek, CS Norbury, M Falco, EE Impey, CD Lehar, J McLeod, BA Rix, HW Keeton, CR Munoz, JA Peng, CY AF Rusin, D Kochanek, CS Norbury, M Falco, EE Impey, CD Lehar, J McLeod, BA Rix, HW Keeton, CR Munoz, JA Peng, CY TI B1359+154: A six-image lens produced by A z similar or equal to 1 compact group of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; gravitational lensing ID GRAVITATIONAL LENS; FERMAT PRINCIPLE; CLUSTER; SYSTEM; EVOLUTION; CLASSIFICATION; CAUSTICS; QUASAR; MODELS; ARC AB Hubble Space Telescope (HET) V- and I-band observations show that the gravitational lens B1359 + 154 consists of six images of a single z(s) = 3.235 radio source and its star-forming host galaxy, produced by a compact group of galaxies at z(l) similar or equal to 1. Very Long Baseline Array (VLBA) observations at 1.7 GHz. strongly support this conclusion, showing six compact cores with similar low-frequency radio spectra. B1359+154 is the first example of galaxy-scale gravitational lensing in which more than four images are observed of the same background source. The configuration is due to the unique lensing mass distribution: three primary lens galaxies lying on the vertices of a triangle separated by 0 " .7 similar or equal to 4 h(-1) kpc, inside the 1 " .7 diameter Einstein ring defined by the radio images. The gravitational potential has additional extrema within this triangle, creating a pair of central images that supplement the "standard" four-image geometry of the outer components. Simple mass models, consisting of three lens galaxies constrained by HST and VLBA astrometry, naturally reproduce the observed image positions but must be finely tuned to fit the flux densities. C1 Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain. RP Univ Penn, Dept Phys & Astron, 209 S 33rd St, Philadelphia, PA 19104 USA. EM drusin@hep.upenn.edu; ckochanek@cfa.harvard.edu; mn@jb.man.ac.uk; efalco@cfa.harvard.edu; impey@as.arizona.edu; jlehar@cfa.harvard.edu; bmcleod@cfa.harvard.edu; rix@mpia-hd.mpg.de; ckeeton@as.arizona.edu; jmunoz@ll.iac.es; cyp@as.arizona.edu NR 49 TC 46 Z9 46 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 AUG PY 2001 VL 557 IS 2 BP 594 EP 604 DI 10.1086/322251 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 467LN UT WOS:000170704800010 ER PT J AU Abu-Zayyad, T Belov, K Bird, DJ Boyer, J Cao, Z Catanese, M Chen, GF Clay, RW Covault, CE Dai, HY Dawson, BR Elbert, JW Fick, BE Fortson, LF Fowler, JW Gibbs, KG Glasmacher, MAK Green, KD Ho, Y Huang, A Jui, CC Kidd, MJ Kieda, DB Knapp, BC Ko, S Larsen, CG Lee, W Loh, EC Mannel, EJ Matthews, J Matthews, JN Newport, BJ Nitz, DF Ong, RA Simpson, KM Smith, JD Sinclair, D Sokolsky, P Sommers, P Song, C Tang, JKK Thomas, SB van der Velde, JC Wiencke, LR Wilkinson, CR Yoshida, S Zhang, XZ AF Abu-Zayyad, T Belov, K Bird, DJ Boyer, J Cao, Z Catanese, M Chen, GF Clay, RW Covault, CE Dai, HY Dawson, BR Elbert, JW Fick, BE Fortson, LF Fowler, JW Gibbs, KG Glasmacher, MAK Green, KD Ho, Y Huang, A Jui, CC Kidd, MJ Kieda, DB Knapp, BC Ko, S Larsen, CG Lee, W Loh, EC Mannel, EJ Matthews, J Matthews, JN Newport, BJ Nitz, DF Ong, RA Simpson, KM Smith, JD Sinclair, D Sokolsky, P Sommers, P Song, C Tang, JKK Thomas, SB van der Velde, JC Wiencke, LR Wilkinson, CR Yoshida, S Zhang, XZ TI Measurement of the cosmic-ray energy spectrum and composition from 10(17) to 10(18.3) eV using a hybrid technique SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; ISM : abundances ID EXTENSIVE AIR SHOWERS; FLYS EYE; DISTRIBUTIONS; CASCADES AB We study the spectrum and average mass composition of cosmic rays with primary energies between 10(17) and 10(18) eV using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the Michigan Muon Array (MIA). Measurements have been made of the change in the depth of shower maximum as a function of energy. A complete Monte Carlo simulation of the detector response and comparisons with shower simulations leads to the conclusion that the cosmic-ray intensity is changing from a heavier to a lighter composition in this energy range. The spectrum is consistent with earlier Fly's Eye measurements and supports the previously found steepening near 4 x 10(17) eV. C1 Univ Utah, High Energy Astrophys Inst, Salt Lake City, UT 84112 USA. Univ Adelaide, Adelaide, SA 5005, Australia. Columbia Univ, Nevis Lab, Irvington, NY 10533 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Adler Planetarium & Astron Museum, Dept Astron, Chicago, IL 60605 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Univ Illinois, Urbana, IL 61801 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. So Univ, Dept Phys, Baton Rouge, LA 70801 USA. Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA. RP Univ Utah, High Energy Astrophys Inst, Salt Lake City, UT 84112 USA. RI Song, Chihwa/A-3455-2008; Belov, Konstantin/D-2520-2013; OI Matthews, James/0000-0002-1832-4420 NR 42 TC 149 Z9 149 U1 0 U2 3 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 AUG PY 2001 VL 557 IS 2 BP 686 EP 699 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 467LN UT WOS:000170704800019 ER PT J AU Ueta, T Meixner, M Hinz, PM Hoffmann, WF Brandner, W Dayal, A Deutsch, LK Fazio, GG Hora, JL AF Ueta, T Meixner, M Hinz, PM Hoffmann, WF Brandner, W Dayal, A Deutsch, LK Fazio, GG Hora, JL TI Subarcsecond mid-infrared structure of the dust shell around IRAS 22272+5435 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; infrared : stars; stars : individual (IRAS 22272+5435; HD 235858, SAO 34504); stars : mass loss ID PROTO-PLANETARY-NEBULAE; RICH PROTOPLANETARY NEBULAE; 21 MU-M; SIZE DISTRIBUTION; CIRCUMSTELLAR ENVELOPES; PREPLANETARY NEBULAE; EMISSION FEATURES; CO OBSERVATIONS; STARS; SPECTROSCOPY AB We report subarcsecond imaging of extended mid-IR emission from a proto-planetary nebula (PPN), IRAS 22272+5435, performed at the MMT observatory with its newly upgraded 6.5 m aperture telescope and at the Keck observatory. The mid-IR emission structure is resolved into two emission peaks separated by 0."5-0."6 in the MMT 11.7 mum image and in the Keck 7.9, 9.7, and 12.5 mum images, corroborating the predictions based on previous multiwavelength morphological studies and radiative transfer calculations. The resolved images show that the PPN dust shell has a toroidal structure with the 0."5 inner radius. In addition, an unresolved mid-IR excess appears at the nebula center. Radiative transfer model calculations suggest that the highly equatorially enhanced (rho (eq \)rho (pole) = 9) structure of the PPN shell was generated by an axisymmetric superwind with overdot(sw) = 4 x 10(-6) M-circle dot yr(-1) which was preceded by a spherical asymptotic giant branch (AGB) wind with overdot(AGB) = 8 x 10(-7) M-circle dot yr(-1). These model calculations also indicate that the superwind shell contains larger dust grains than the AGB wind shell. The unresolved mid-IR excess may have been produced by a post-AGB mass loss at a rate of 2-6 x 10(-7) M-circle dot yr(-1). While the central star left the AGB about 380 yr ago after the termination of the superwind, the star seems to have been experiencing an ambient post-AGB mass loss with a sudden, increased mass ejection about 10 yr ago. C1 Univ Illinois, Dept Astron, MC221, Urbana, IL 61801 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. KLA Tencor Corp, San Jose, CA 95134 USA. Boston Univ, Dept Astron, Boston, MA 02215 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Ueta, T (reprint author), Univ Illinois, Dept Astron, MC221, 1002 W Green St, Urbana, IL 61801 USA. OI Hora, Joseph/0000-0002-5599-4650 NR 68 TC 38 Z9 38 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 AUG PY 2001 VL 557 IS 2 BP 831 EP 843 DI 10.1086/322259 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 467LN UT WOS:000170704800032 ER PT J AU Harwit, M Malfait, K Decin, L Waelkens, C Feuchtgruber, H Melnick, GJ AF Harwit, M Malfait, K Decin, L Waelkens, C Feuchtgruber, H Melnick, GJ TI The infrared continuum spectrum of VY Canis Majoris SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; infrared : stars; molecular processes; stars : abundances; stars : individual (VY Canis Majoris); supergiants ID LATE-TYPE STARS; INTERSTELLAR SILICATE MINERALOGY; CIRCUMSTELLAR DUST; SUBMILLIMETER OBSERVATIONS; ENERGY-DISTRIBUTIONS; EVOLVED STARS; WATER-VAPOR; DISKS; ENVELOPES; GRAINS AB We combine spectra of VY CMa obtained with the short- and long-wavelength spectrometers, SWS and LWS, on the Infrared Space Observatory(3) to provide a first detailed continuum spectrum of this highly luminous star. The circumstellar dust cloud through which the star is observed is partially self-absorbing, which makes for complex computational modeling. We review previous work and comment on them range of uncertainties about the physical traits and mineralogical composition of the modeled disk. We show that these uncertainties significantly affect the modeling of the outflow and the estimated mass loss. In particular, we demonstrate that a variety of quite diverse models can produce good fits to the observed spectrum. If the outflow is steady, and the radiative repulsion on the dust cloud dominates the star's gravitational attraction, we show that the total dust mass loss rate is similar to4 x 10(-6) M-circle dot yr(-1), assuming that the star is at. a distance of 1.5 kpc. Several indications, however, suggest that the outflow from the star may be spasmodic. We discuss this and other problems facing the construction of a physically coherent model of the dust cloud and a realistic mass-loss analysis. C1 Katholieke Univ Leuven, Inst Voor Sterrenkunde, B-3001 Heverlee, Belgium. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. BARCO Project Syst, B-8520 Kuurne, Belgium. RP Harwit, M (reprint author), 511 H St SW, Washington, DC 20024 USA. NR 43 TC 29 Z9 29 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG PY 2001 VL 557 IS 2 BP 844 EP 853 DI 10.1086/321684 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 467LN UT WOS:000170704800033 ER PT J AU Narayan, R Piran, T Kumar, P AF Narayan, R Piran, T Kumar, P TI Accretion models of gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; gamma rays : bursts; gamma rays : theory ID BLACK-HOLES; DOMINATED ACCRETION; FLOWS; DISKS; CONVECTION; VARIABILITY; SUPERNOVAE; VISCOSITY; MERGERS AB Many models of gamma-ray bursts (GRBs) involve accretion onto a compact object, usually a black hole, at a mass accretion rate on the order of a fraction of a solar mass per second. If the accretion disk is larger than a few tens or hundreds of Schwarzschild radii, the accretion will proceed via a convection-dominated accretion flow (CDAF) in which most of the matter escapes to infinity rather than falling onto the black hole. Models involving the mergers of black hole-white dwarf binaries and black hole-helium star binaries fall in this category. These models are unlikely to produce GRBs since very little mass reaches the black hole. If the accretion disk is smaller, then accretion will proceed via neutrino cooling in a neutrino-dominated accretion disk (NDAF) and most of the mass will reach the center. Models involving the mergers of double neutron star binaries and black hole-neutron star binaries fall in this category and are capable of producing bright GRBs. If the viscosity parameter a in the NDAF has a standard value of similar to0.1, these mergers can explain short GRBs with durations under a second, but they are unlikely to produce long GRBs with durations of tens or hundred of seconds. If the accretion disk is fed by fallback of material after a supernova explosion, as in the collapsar model, then the timescale of the burst is determined by fallback, not accretion. Such a model can produce long GRBs. Fallback models again require that the accretion should proceed via an NDAF rather than a CDAF in order for a significant amount of mass to reach the black hole. This condition imposes an upper limit on the radius of injection of the gas. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Inst Adv Studies, Princeton, NJ 08540 USA. RP Narayan, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Narayan, Ramesh/0000-0002-1919-2730 NR 47 TC 250 Z9 253 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG PY 2001 VL 557 IS 2 BP 949 EP 957 DI 10.1086/322267 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 467LN UT WOS:000170704800043 ER PT J AU Furlanetto, SR Loeb, A AF Furlanetto, SR Loeb, A TI Intergalactic magnetic fields from quasar outflows SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; intergalactic medium; magnetic fields; quasars : general ID EXTRAGALACTIC RADIO-SOURCES; ACTIVE GALACTIC NUCLEI; LY-ALPHA FOREST; SUPERNOVA REMNANT; FARADAY-ROTATION; COMA-CLUSTER; COSMOLOGICAL REIONIZATION; VLA OBSERVATIONS; HIGH-ENERGY; DISK WINDS AB Outflows from quasars inevitably pollute the intergalactic medium (IGM) with magnetic fields. The short-lived activity of a quasar leaves behind an expanding magnetized bubble in the IGM. We model the expansion of the remnant quasar bubbles and calculate their distribution as a function of size and magnetic field strength at different redshifts. We generically find that by a redshift z similar to 3, about 5%-20% of the IGM volume is filled by magnetic fields with an energy density greater than or similar to 10% of the mean thermal energy density of a photoionized IGM (at similar to 10(4) K). As massive galaxies and X-ray clusters condense out of the magnetized IGM, the adiabatic compression of the magnetic field could result in the field strength observed in these systems without a need for further dynamo amplification. The intergalactic magnetic field could also provide a nonthermal contribution to the pressure of the photoionized gas that may account for the claimed discrepancy between the simulated and observed Doppler width distributions of the Ly alpha forest. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Furlanetto, SR (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 93 TC 134 Z9 134 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 AUG 1 PY 2001 VL 556 IS 2 BP 619 EP 634 DI 10.1086/321630 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462NC UT WOS:000170425300008 ER PT J AU Green, PJ Forster, K Kuraszkiewicz, J AF Green, PJ Forster, K Kuraszkiewicz, J TI Quasar evolution and the Baldwin effect in the large bright quasar survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : emission lines; quasars : general; ultraviolet : galaxies ID ACTIVE GALACTIC NUCLEI; DIGITAL SKY SURVEY; EMISSION-LINES; ELEMENTAL ABUNDANCES; REDSHIFT QUASARS; STELLAR OBJECTS; STAR-FORMATION; QSO SAMPLE; GALAXIES; LUMINOSITY AB From a large homogeneous sample of optical/UV emission line measurements for 993 quasars from the Large Bright Quasar Survey (LBQS), we study correlations between emission-line equivalent width and both rest-frame ultraviolet luminosity (i.e., the Baldwin effect) and redshift. Our semiautomated spectral fitting accounts for absorption lines, fits blended iron emission, and provides upper limits to weak emission lines. Use of a single large, well-defined sample and consistent emission-line measurements allows us to sensitively detect many correlations, most of which have been previously noted. A new finding is a significant Baldwin effect in UV iron emission. Further analysis reveals that the primary correlation of iron emission strength is probably with redshift, implying an evolutionary rather than a luminosity effect. We show that for most emission lines with a significant Baldwin effect, and for some without, evolution dominates over luminosity effects. This may reflect evolution in abundances, in cloud covering factors, or overall cloud conditions such as density and ionization. We find that in our sample, a putative correlation between Baldwin effect slope and the ionization potential is not significant. Uniform measurements of other large quasar samples will extend the luminosity and redshift range of such spectral studies and provide even stronger tests of spectral evolution. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Green, PJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 75 TC 39 Z9 39 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 AUG 1 PY 2001 VL 556 IS 2 BP 727 EP 737 DI 10.1086/321600 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462NC UT WOS:000170425300015 ER PT J AU Walker, RC Benson, JM Unwin, SC Lystrup, MB Hunter, TR Pilbratt, G Hardee, PE AF Walker, RC Benson, JM Unwin, SC Lystrup, MB Hunter, TR Pilbratt, G Hardee, PE TI The structure and motions of the 3C 120 radio jet on scales of 0.6-300 parsecs SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (3C 120); galaxies : jets; hydrodynamics radio; continuum : galaxies; relativity ID SUPERLUMINAL MOTION; MERLIN OBSERVATIONS; RELATIVISTIC JETS; GALAXY 3C120; 3C-120; VARIABILITY; EMISSION; 3C-345; VLBI; GHZ AB Results are presented from long-term very long baseline interferometry monitoring of the parsec-scale radio jet in 3C 120 at 5 and 1.7 GHz. The 5 GHz sequence includes a few early epochs at 10.7 GHz. Superluminal features are seen leaving the core at intervals of less than a year, about as often as new features could be distinguished with the 0.6 pc resolution of the observations. The underlying jet is continuous but not smooth, and the measured features are simply the bright points in the convolution of the observing beam with brightness fluctuations that occur on many scales. The velocity of different features varies, but not by more than about a factor of 2. Clear variations in the velocity of an individual feature are not seen. Some features that were observed leaving the core in the 5 GHz observations with 0.6 pc resolution are followed at 1.7 GHz with 2.4 pc resolution to projected distances in excess of 25 pc from the core. Older features up to at least 150 pc in projection from the core are still moving at superluminal apparent speeds and are therefore presumed to be relativistic. Beyond that, the data are inadequate for motion measurements. The region where the jet slows to nonrelativistic speeds has not been found. There are suggestions of stationary features, or brightening and dimming regions, through which the moving features pass. These may be locations where there is interaction with the external medium, or they may simply be the result of variations in the jet angle to the line of sight. The observation of stationary features in an otherwise moving jet reinforces the idea that the lack of motion of the knot at 4 " (2 kpc), which has been found not to be superluminal in other observations, might not actually imply that the jet has slowed by that position. The structure of the jet in the vicinity of the most likely stationary feature is suggestive of a helical pattern seen in projection. The deprojected wavelength of the pattern is very long relative to the jet radius, unlike the situation in sources such as M87 (Owen and coworkers). If the 3C 120 jet does contain a slowly moving, helical structure, then theory suggests that the jet resides in a relatively cool medium, not in a relativistically hot cocoon or lobe. C1 Natl Radio Astron Observ, Socorro, NM 87801 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Portland State Univ, Portland, OR 97207 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. ESA, Div Astrophys, Dept Space Sci, Noordwijk, Netherlands. Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. RP Walker, RC (reprint author), Natl Radio Astron Observ, Socorro, NM 87801 USA. NR 36 TC 34 Z9 34 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 2001 VL 556 IS 2 BP 756 EP 772 DI 10.1086/321548 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462NC UT WOS:000170425300018 ER PT J AU Cotera, AS Whitney, BA Young, E Wolff, MJ Wood, K Povich, MV Schneider, G Rieke, M Thompson, R AF Cotera, AS Whitney, BA Young, E Wolff, MJ Wood, K Povich, MV Schneider, G Rieke, M Thompson, R TI High-resolution near-infrared images and models of the circumstellar disk in HH 30 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; radiative transfer; stars : individual (HH 30); stars : pre-main-sequence; stars : rotation; stars : spots ID T-TAURI STARS; YOUNG STELLAR OBJECTS; MAGNETOCENTRIFUGALLY DRIVEN FLOWS; SPECTRAL ENERGY-DISTRIBUTIONS; MAGNETIC NEUTRON-STARS; ACCRETION DISKS; HH 30; ROTATIONAL EVOLUTION; INTERSTELLAR DUST; DARK CLOUD AB We present Hubble Space Telescope near-infrared camera and multiobject spectrometer observations of the reflection nebulosity associated with the T Tauri star HH 30. The images show the scattered-light pattern characteristic of a highly inclined, optically thick disk with a prominent dust lane whose width decreases with increasing wavelength. The reflected nebulosity exhibits a lateral asymmetry in the upper lobe on the opposite side to that reported in previously published Wide Field Planetary Camera 2 images. The radiation transfer model that most closely reproduces the data has a flared accretion disk with dust grains larger than standard interstellar medium grains by a factor of approximately 2.1. A single hot spot on the stellar surface provides the necessary asymmetry to fit the images and is consistent with previous modeling of the light curve and images. Photometric analysis results in an estimated extinction of A(V) greater than or similar to 80; however, since the photometry measures only scattered light rather than direct stellar flux, this a lower limit. The radiative transfer models require an extinction of A(V) = 7900. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Space Sci Inst, Boulder, CO 80303 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. RP Cotera, AS (reprint author), Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA. EM cotera@as.arizona.edu; bwhitney@colorado.edu; eyoung@as.arizona.edu; wolff@colorado.edu; kwood@cfa.harvard.edu; gschneider@stsci.edu; mrieke@as.arizona.edu; rthompson@as.arizona.edu NR 55 TC 89 Z9 89 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 AUG 1 PY 2001 VL 556 IS 2 BP 958 EP 969 DI 10.1086/321627 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462NC UT WOS:000170425300036 ER PT J AU Chou, HS AF Chou, HS TI Numerical analysis of magnetic field amplification by turbulence SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; turbulence; methods : numerical ID DISSIPATION AB We apply a Fourier spectral numerical method to the study of three-dimensional incompressible MHD turbulence with a magnetic Prandtl number Pr greater than or equal to 1. We examine the processes by which an initially weak, large-scale seed magnetic field and an initially weak, small-scale, impulse-like seed magnetic field are amplified. We find that in both cases the magnetic energy spectrum grows at all scales. The growth rates at different amplification stages are analyzed. For a large-scale seed magnetic field, the magnetic energy density grows as similar tot(2) for the first few turbulence eddy turnover times, followed by a dynamic growth stage, where nonlinear interactions between different scales of the turbulence contribute to an exponential growth rate that is largely determined by the turbulence eddy turnover time. For a seed magnetic field that is initially set up at a small scale in the turbulence, during the kinematic development stage, the growth rate of magnetic energy is proportional to1/tau (max), where tau (max) is the eddy turnover time of the smallest eddies of the turbulence. The kinematic growth stage is followed by a dynamic growth stage, where nonlinearity plays important role. During such dynamic growth stage, the growth rate of total magnetic energy is determined by both the magnetic energy amplification within the turbulence inertial range and that within the turbulence dissipation range. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Chou, HS (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 14 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 AUG 1 PY 2001 VL 556 IS 2 BP 1038 EP 1051 DI 10.1086/321607 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462NC UT WOS:000170425300044 ER PT J AU Moran, EC Kay, LE Davis, M Filippenko, AV Barth, AJ AF Moran, EC Kay, LE Davis, M Filippenko, AV Barth, AJ TI A composite Seyfert 2 X-ray spectrum: Implications for the origin of the cosmic X-ray background SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : Seyfert; X-rays : diffuse background; X-rays : galaxies ID DEEP SURVEY; 2 GALAXIES; MAXIMA-1; FIELD; AGN AB We present a composite 1-10 keV Seyfert 2 X-ray spectrum derived from ASCA observations of a distance-limited sample of nearby galaxies. All 29 observed objects were detected. Above similar to3 keV, the composite spectrum is inverted, confirming that Seyfert 2 galaxies as a class have the spectral properties necessary to explain the flat shape of the cosmic X-ray background spectrum. Integrating the composite spectrum over redshift, we find that the total emission from Seyfert 2 galaxies, combined with the expected contribution from unabsorbed type I objects, provides an excellent match to the spectrum and intensity of the hard X-ray background. The principal uncertainty in this procedure is the cosmic evolution of the Seyfert 2 X-ray luminosity function. Separate composite spectra for objects in our sample with and without polarized broad optical emission lines are also presented. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Columbia Univ Barnard Coll, Dept Phys & Astron, New York, NY 10027 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Moran, EC (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. OI Barth, Aaron/0000-0002-3026-0562 NR 22 TC 30 Z9 30 U1 0 U2 2 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 AUG 1 PY 2001 VL 556 IS 2 BP L75 EP L78 DI 10.1086/322991 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462ND UT WOS:000170425400003 ER PT J AU Smith, RK Brickhouse, NS Liedahl, DA Raymond, JC AF Smith, RK Brickhouse, NS Liedahl, DA Raymond, JC TI Collisional plasma models with APEC/APED: Emission-line diagnostics of hydrogen-like and helium-like ions SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes; plasmas; radiation mechanisms : thermal; X-rays : general ID HE-LIKE IONS; PHOTOIONIZATION CROSS-SECTIONS; ISOELECTRONIC SEQUENCE; RATE COEFFICIENTS; ATOMIC DATABASE; ELECTRON-IMPACT; EXCITATION; SPECTRA; RADIATION; ELEMENTS AB New X-ray observatories (Chandra and XHM-Newton) are providing a wealth of high-resolution X-ray spectra in which hydrogen- and helium-like ions are usually strong features. We present results from a new collisional-radiative plasma code, the Astrophysical Plasma Emission Code (APEC), which uses atomic data in the companion Astrophysical Plasma Emission Database (APED) to calculate spectral models for hot plasmas. APED contains the requisite atomic data such as collisional and radiative rates, recombination cross sections, dielectronic recombination rates, and satellite line wavelengths. We compare the APEC results to other plasma codes for hydrogen- and helium-like diagnostics and test the sensitivity of our results to the number of levels included in the models. We find that dielectronic recombination with hydrogen-like ions into high (n = 6-10) principal quantum numbers affects some helium-like line ratios from low-lying (n = 2) transitions. C1 Harvard Smithsonian Ctr Astrophys, High Energy Astrophys Div, Cambridge, MA 02138 USA. Lawrence Livermore Natl Lab, Dept Phys & Adv Technol, Livermore, CA 94550 USA. Harvard Smithsonian Ctr Astrophys, Solar & Steller Phys Div, Cambridge, MA 02138 USA. RP Smith, RK (reprint author), Harvard Smithsonian Ctr Astrophys, High Energy Astrophys Div, 60 Garden St, Cambridge, MA 02138 USA. OI Brickhouse, Nancy/0000-0002-8704-4473 NR 38 TC 746 Z9 747 U1 5 U2 19 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 AUG 1 PY 2001 VL 556 IS 2 BP L91 EP L95 DI 10.1086/322992 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 462ND UT WOS:000170425400007 ER PT J AU Glenn, J Hunter, TR AF Glenn, J Hunter, TR TI A comparison of tracers of cool gas in galaxies and the (CO)-C-12/(CO)-C-13 luminosity ratio in luminous infrared galaxies SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : active; galaxies : interactions; galaxies : ISM; ISM : atoms; ISM : dust, extinction; ISM : molecules ID MOLECULAR GAS; ATOMIC CARBON; EMISSION; MERGERS; (CO)-C-13; SYSTEM; CLOUDS AB We present new observations of (CO)-C-12 (J=2-1), (CO)-C-13 (J=2-1), and 1.3 mm dust continuum emission toward seven diverse galaxies (IC 10, IRAS 10565+2448, the Antennae-NGC 4038 and 4039, NGC 4736, Mrk 231, and NGC 6090). Compared with the other galaxies in the sample, the two ultraluminous infrared galaxies (ULIGs) exhibit reduced (CO)-C-13 line luminosities with respect to the (CO)-C-12 line luminosities and 1.3 mm dust luminosities. These observations parallel the established trend of large R-values in ULIGs compared with more quiescent spiral galaxies. The two luminous merging pairs in our sample with moderate starburst activity, the Antennae and NGC 6090, do not appear to show the large R-values. The results are consistent with models in which (CO)-C-12 emission is dominated in the most luminous mergers by warm regions of ISM with moderate optical depths For the other galaxies, (tau (12CO)similar to1). R is more typical of the optically thick case 102.0.CO;2 PG 12 WC Zoology SC Zoology GA 465NV UT WOS:000170597600019 ER PT J AU McShea, WJ Aung, M Poszig, D Wemmer, C Monfort, S AF McShea, WJ Aung, M Poszig, D Wemmer, C Monfort, S TI Forage, habitat use, and sexual segregation by a tropical deer (Cervus eldi thamin) in a dipterocarp forest SO JOURNAL OF MAMMALOGY LA English DT Article DE Cervus eldi; dipterocarp forest; habitat selection; Myanmar; sex differences; thamin; tropical ecology ID CONSTRAINTS; SELECTION; SHEEP AB We monitored use of plants and habitat in a population of thamin (Cervis eldi thamin) in Chatthin Wildlife Sanctuary in central Myanmar from 1996 through 1999. Habitat use within the deciduous dipterocarp forest was monitored by radiotracking 19 individuals during daylight hours and conducting biannual fecal pellet surveys along 87 km of marked transects. Habitat abundance was determined by classifying a LANDSAT image of the region, collecting vegetation parameters at 201 plots located within the sanctuary, and pacing habitat types along marked transects. Thamin consumed primarily forbs, grasses, and agricultural crops but also fruits of 8 common tree species. Thamin used dipterocarp forest habitat but showed some seasonal shifts and distinct individual differences in habitat use. Except during of the mating season (January-April), females were found more often in degraded forests and closer to crops than males. Sex differences in habitat selection were due to either female selection of habitats with lower predation risk or increased nutritional needs associated with lactation. C1 Natl Zool Pk, Conservat & Res Ctr, Front Royal, VA 22630 USA. Forest Dept, Nat & Wildlife Conservat Div, Rangoon, Myanmar. Univ Marburg, Dept Anim Ecol, D-35032 Marburg, Germany. RP McShea, WJ (reprint author), Natl Zool Pk, Conservat & Res Ctr, Front Royal, VA 22630 USA. NR 35 TC 21 Z9 24 U1 3 U2 8 PU AMER SOC MAMMALOGISTS PI PROVO PA BRIGHAM YOUNG UNIV, DEPT OF ZOOLOGY, PROVO, UT 84602 USA SN 0022-2372 J9 J MAMMAL JI J. Mammal. PD AUG PY 2001 VL 82 IS 3 BP 848 EP 857 DI 10.1644/1545-1542(2001)082<0848:FHUASS>2.0.CO;2 PG 10 WC Zoology SC Zoology GA 465NV UT WOS:000170597600020 ER PT J AU Ralls, K Pilgrim, KL White, PJ Paxinos, EE Schwartz, MK Fleischer, RC AF Ralls, K Pilgrim, KL White, PJ Paxinos, EE Schwartz, MK Fleischer, RC TI Kinship social relationships, and den sharing in kit foxes SO JOURNAL OF MAMMALOGY LA English DT Article DE dens; DNA; kinship; mating systems; microsatellites; relatedness; San Joaquin kit fox; social organization; Vulpes macrotis mutica ID PATTERNS; CANIDAE; POPULATION; PHILOPATRY; DISPERSAL; REPEATS; MARKERS; COYOTE; PREY; DOG AB We used 11 microsatellites, highly variable nuclear markers, to infer kinship among 35 San Joaquin kit foxes,Vulpes macrotis mutica, and combined this information with field observations to gain insight into fox social behavior. Fox social units consisted of solitary foxes, mated mate-female pairs, and trios consisting of a mated pair plus another adult. Pair-mates were not closely related. The additional adult (1 male, 1 female) in 2 trios was the offspring of at least 1 of the pair-mates. Foxes living on adjacent home ranges tended to be more closely related than foxes that did not live on adjacent home ranges, largely because females on adjacent home ranges were often closely related. F-IS values indicated a deficiency of homozygotes that was likely due to clusters of relatives living on adjacent home ranges. Foxes that shared the same den on the same day were usually members of the same social group. Contrary to expectations, however, we sometimes found foxes sharing dens with foxes from other social groups. Many cases involved unpaired individuals and appeared to be unsuccessful attempts at pair formation. Other cases involved members of 2 adjacent social groups, a pair and a trio. Both members of the pair were closely related to 1 member of the trio, indicating that kit foxes can maintain enduring social relationships with adult offspring or siblings that have dispersed to a new home range and found a mate. C1 Smithsonian Inst, Natl Zool Pk, Conservat & Res Ctr, Washington, DC 20008 USA. US Fish & Wildlife Serv, Carlsbad, CA 92008 USA. Univ Montana, Wildlife Biol Program, Missoula, MT 59812 USA. RP Ralls, K (reprint author), Smithsonian Inst, Natl Zool Pk, Conservat & Res Ctr, Washington, DC 20008 USA. RI Schwartz, Michael/C-3184-2014 OI Schwartz, Michael/0000-0003-3521-3367 NR 36 TC 35 Z9 36 U1 2 U2 21 PU AMER SOC MAMMALOGISTS PI PROVO PA BRIGHAM YOUNG UNIV, DEPT OF ZOOLOGY, PROVO, UT 84602 USA SN 0022-2372 J9 J MAMMAL JI J. Mammal. PD AUG PY 2001 VL 82 IS 3 BP 858 EP 866 DI 10.1644/1545-1542(2001)082<0858:KSRADS>2.0.CO;2 PG 9 WC Zoology SC Zoology GA 465NV UT WOS:000170597600021 ER PT J AU Pyke, CR Condit, R Aguilar, S Lao, S AF Pyke, CR Condit, R Aguilar, S Lao, S TI Floristic composition across a climatic gradient in a neotropical lowland forest SO JOURNAL OF VEGETATION SCIENCE LA English DT Article DE gradient analysis; life zone; precipitation; spatial analysis; tropical lowland forest ID RAIN-FOREST; SPECIES COMPOSITION; DENSITY-DEPENDENCE; POLLEN RECORD; TREE; ORDINATION; DIVERSITY; AREA; BIODIVERSITY; DYNAMICS AB This study deals with the floristic composition of lowland tropical forest in the watershed of the Panama Canal, The floristic composition of large trees in 54 forest plots was analysed with respect to environmental factors, including precipitation, geologic parent material, stand age, topography, and soils. The plots contain 824 species of trees with a diameter at breast height greater than or equal to 10 cm and represent a regional flora with exceptional beta -diversity. Plot data indicate that the Panamanian forest is strongly spatially structured at the landscape scale with floristic similarity decreasing rapidly as a function of inter-plot geographic distance, especially for distances < 5 km. The ordinations and patterns of endemism across the study area indicate broad floristic associations well correlated with Holdridge life zones. The results indicate the positive aspects of life zone classification at regional scales, while simultaneously highlighting its inadequacy for finer scales of analysis and resource management. Multivariate gradient analysis techniques (Non-metric Multidimensional Distance Scaling and Detrended Correspondence Analysis) show clear patterns of floristic variability correlated with regional precipitation trends, surficial geology, and local soil attributes. Geologic and edaphic conditions, such as acidic soils or excessively drained limestone substrates. appear to override the effects of precipitation and modify forest composition. We conclude that the Panamanian forest shows clear patterns of spatial organization along environmental gradients. predominantly precipitation. The rapid decline in floristic similarity with distance between stands also suggests a role for dispersal limitation and stochastic events. C1 Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. Smithsonian Inst, Ctr Trop Forest Sci, Smithsonian Trop Res Inst, Washington, DC 20560 USA. RP Pyke, CR (reprint author), Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. NR 53 TC 133 Z9 142 U1 4 U2 39 PU OPULUS PRESS UPPSALA AB PI LANNA PA MALMEN, S-740 11 LANNA, SWEDEN SN 1100-9233 J9 J VEG SCI JI J. Veg. Sci. PD AUG PY 2001 VL 12 IS 4 BP 553 EP 566 DI 10.2307/3237007 PG 14 WC Plant Sciences; Ecology; Forestry SC Plant Sciences; Environmental Sciences & Ecology; Forestry GA 489GT UT WOS:000171984200012 ER PT J AU Stahl, J AF Stahl, J TI Dance masters: Interviews with legends of dance. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Amer Art Museum, Washington, DC USA. RP Stahl, J (reprint author), Smithsonian Amer Art Museum, Washington, DC USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD AUG PY 2001 VL 126 IS 13 BP 112 EP 112 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 463MR UT WOS:000170480400135 ER PT J AU Riley, S AF Riley, S TI Lit life. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC USA. RP Riley, S (reprint author), Smithsonian Inst Lib, Washington, DC USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD AUG PY 2001 VL 126 IS 13 BP 160 EP 160 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 463MR UT WOS:000170480400363 ER PT J AU Riley, S AF Riley, S TI About the author. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC USA. RP Riley, S (reprint author), Smithsonian Inst Lib, Washington, DC USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD AUG PY 2001 VL 126 IS 13 BP 160 EP 160 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 463MR UT WOS:000170480400362 ER PT J AU Binzel, RP Rivkin, AS Bus, SJ Sunshine, JM Burbine, TH AF Binzel, RP Rivkin, AS Bus, SJ Sunshine, JM Burbine, TH TI MUSES-C target asteroid (25143) 1998 SF36: A reddened ordinary chondrite SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID EROS AB Near-Earth asteroid (25143) 1998 SF36 is a planned target for the Japanese MUSES-C sample return mission. High signal-to-noise and relatively high-resolution (50 Angstrom) visible and near-infrared spectroscopic measurements obtained during this asteroid's favorable 2001 apparition reveal it to have a red-sloped S(IV)-type spectrum with strong 1 and 2 mum absorption bands analogous to those measured for ordinary chondrite meteorites. This red slope, which is the primary spectral difference between (25143) 1998 SF36 and ordinary chondrite meteorites, is well modeled by the spectrum of 0.05% nanophase iron (npFe(0)) proposed as a weathering mechanism by Pieters et al. (2000). Asteroid 1998 SF36 appears to have a surface composition corresponding to that of ordinary chondrite meteorites and is most similar in spectral characteristics and modeled olivine/pyroxene content to the LL chondrite class. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Inst Astron, Hilo, HI 96720 USA. Sci Applicat Int Corp, Adv Technol Applicat Div, Chantilly, VA USA. Natl Museum Nat Hist, Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. RP Binzel, RP (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Rivkin, Andrew/B-7744-2016 OI Rivkin, Andrew/0000-0002-9939-9976 NR 27 TC 86 Z9 86 U1 1 U2 4 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD AUG PY 2001 VL 36 IS 8 BP 1167 EP 1172 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 465PN UT WOS:000170599300013 ER PT J AU Williams, ST Knowlton, N AF Williams, ST Knowlton, N TI Mitochondrial pseudogenes are pervasive and often insidious in the snapping shrimp genus Alpheus SO MOLECULAR BIOLOGY AND EVOLUTION LA English DT Article DE Alpheus; cytochrome oxidase I; pseudogene; numt ID HUMAN NUCLEAR GENOME; DNA; SEQUENCES; EVOLUTION; MTDNA; RATES; HETEROPLASMY; DROSOPHILA; DIVERGENCE; PANAMA AB Here we show that multiple DNA sequences, similar to the mitochondrial cytochrome oxidase I (COI) gene, occur within single individuals in at least 10 species of the snapping shrimp genus Alpheus. Cloning of amplified products revealed the presence of copies that differed in length and (more frequently) in base substitutions. Although multiple copies were amplified in individual shrimp from total genomic DNA (gDNA), only one sequence was amplified from cDNA. These results are best explained by the presence of nonfunctional duplications of a portion of the mtDNA, probably located in the nuclear genome, since transfer into the nuclear gene would render the COI gene nonfunctional due to differences in the nuclear and mitochondrial genetic codes. Analysis of codon variation suggests that there have been 21 independent transfer events in the 10 species examined. Within a single animal, differences between the sequences of these pseudogenes ranged from 0.2% to 20.6%, and those between the real mtDNA and pseudogene sequences ranged from 0.2% to 18.8% (uncorrected). The large number of integration events and the large range of divergences between pseudogenes and mtDNA sequences suggest that genetic material has be-on repeatedly transferred from the mtDNA to the nuclear genome of snapping shrimp. Unrecognized pseudogenes in phylogenetic or population studies may result in spurious results, although previous estimates of rates of molecular evolution based on Alpheus sister taxa separated by the Isthmus of Panama appear to remain valid. Especially worrisome for researchers are those pseudogenes that are not obviously recognizable as such. An effective solution may be to amplify transcribed copies of protein-coding mitochondrial genes from cDNA rather than using genomic DNA. C1 Smithsonian Trop Res Inst, Naos Marine Lab, Panama City, Panama. Univ Calif San Diego, Scripps Inst Oceanog, Marine Biol Res Div 0202, La Jolla, CA 92093 USA. RP Williams, ST (reprint author), Nat Hist Museum, Dept Zool, Mollusca Res Grp, Cromwell Rd, London SW7 5BD, England. RI Williams, Suzanne/A-9604-2008 OI Williams, Suzanne/0000-0003-2995-5823 NR 45 TC 124 Z9 131 U1 1 U2 21 PU SOC MOLECULAR BIOLOGY EVOLUTION PI LAWRENCE PA PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0737-4038 J9 MOL BIOL EVOL JI Mol. Biol. Evol. PD AUG PY 2001 VL 18 IS 8 BP 1484 EP 1493 PG 10 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 459WY UT WOS:000170275500007 PM 11470839 ER PT J AU Simmons, RB Weller, SJ AF Simmons, RB Weller, SJ TI Utility and evolution of cytochrome b in insects SO MOLECULAR PHYLOGENETICS AND EVOLUTION LA English DT Article DE cytochrome b; Insecta; metabolic rate hypothesis ID MITOCHONDRIAL-DNA EVOLUTION; RIBOSOMAL-RNA; PHYLOGENETIC-RELATIONSHIPS; MOLECULAR SYSTEMATICS; NUCLEOTIDE-SEQUENCE; GENE ORGANIZATION; METABOLIC-RATE; BODY-SIZE; HYMENOPTERA; LEPIDOPTERA AB Cytochrome b (cyt-b) is widely used in molecular phylogenetic studies of vertebrate, but not invertebrate, taxa. To determine whether this situation is an historical accident or reflects the utility of cyt-b, we compared the abilities of cyt-b, COI, and one nuclear ribosomal gene region (D1 of 28S) to recover intergeneric relationships within the tiger moth tribes Ctenuchini and Euchromiini. Additionally, we compared the rate of sequence and amino acid evolution of cyt-b across insects. Cytochrome b had the same level of sequence variation and A/T bias as COI, but was less useful for recovering intergeneric relationships. The total evidence tree casts doubt on the traditional taxonomy of the group. For the class Insecta, we found that functional conservation of amino acids occurs for the same regions as those found in vertebrates with the exception of Mallophaga (lice). Lice have an accelerated rate of nonsynonymous substitutions. Accelerated rate of cyt-b nucleotide and amino acid evolution in Apidae (bees) may be correlated with increased metabolic rates associated with facultative endothermy (= heterothermy). (C) 2001 Academic Press. C1 Univ Minnesota, Dept Entomol, St Paul, MN 55108 USA. Bell Museum Nat Hist, St Paul, MN 55108 USA. RP Simmons, RB (reprint author), Smithsonian Inst, Systemat Entomol Lab, Dept Systemat Biol, Washington, DC 20560 USA. NR 58 TC 75 Z9 92 U1 2 U2 13 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1055-7903 J9 MOL PHYLOGENET EVOL JI Mol. Phylogenet. Evol. PD AUG PY 2001 VL 20 IS 2 BP 196 EP 210 DI 10.1006/mpev.2001.0958 PG 15 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 462FE UT WOS:000170409400004 PM 11476629 ER PT J AU Gehrig, H Heute, V Kluge, M AF Gehrig, H Heute, V Kluge, M TI New partial sequences of phosphoenolpyruvate carboxylase as molecular phylogenetic markers SO MOLECULAR PHYLOGENETICS AND EVOLUTION LA English DT Article DE crassulacean acid metabolism (CAM); photosynthesis (C-3, C-4); molecular taxonomy; molecular evolution; phosphoenolpyruvate carboxylase (PEPC) ID CRASSULACEAN ACID METABOLISM; COMPLETE NUCLEOTIDE-SEQUENCE; SEED PLANT PHYLOGENY; GENE FAMILY; MESEMBRYANTHEMUM-CRYSTALLINUM; CDNA SEQUENCE; CAM-PLANT; EXTANT GYMNOSPERMS; C-4 PHOTOSYNTHESIS; FLAVERIA-TRINERVIA AB To better understand the evolution of the enzyme phosphoenolpyruvate carboxylase (PEPC) and to test its versatility as a molecular character in phylogenetic and taxonomic studies, we have characterized and compared 70 new partial PEPC nucleotide and amino acid sequences (about 1100 by of the 3 ' side of the gene) from 50 plant species (24 species of Bryophyta, 1 of Pteridophyta, and 25 of Spermatophyta). Together with previously published data, the new set of sequences allowed us to construct the up to now most complete phylogenetic tree of PEPC, where the PEPC sequences cluster according to both the taxonomic positions of the donor plants and the assumed specific function of the PEPC isoforms. Altogether, the study further strengthens the view that PEPC sequences can provide interesting information for the reconstruction of phylogenetic relations between organisms and metabolic pathways. To avoid confusion in future discussion, we propose a new nomenclature for the denotation of PEPC isoforms: (C) 2001. Academic Press. C1 Smithsonian Trop Res Inst, Unit 0948, APO AA, APO, AA 34002 USA. Tech Univ Darmstadt, D-64287 Darmstadt, Germany. RP Gehrig, H (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO AA, APO, AA 34002 USA. NR 82 TC 29 Z9 32 U1 1 U2 5 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1055-7903 J9 MOL PHYLOGENET EVOL JI Mol. Phylogenet. Evol. PD AUG PY 2001 VL 20 IS 2 BP 262 EP 274 DI 10.1006/mpev.2001.0973 PG 13 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 462FE UT WOS:000170409400009 PM 11476634 ER PT J AU Czerny, B Nikolajuk, M Piasecki, M Kuraszkiewicz, J AF Czerny, B Nikolajuk, M Piasecki, M Kuraszkiewicz, J TI Black hole masses from power density spectra: determinations and consequences SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Review DE accretion, accretion discs; black hole physics; binaries : general; galaxies : active; galaxies : Seyfert; X-rays : stars ID ACTIVE GALACTIC NUCLEI; X-RAY VARIABILITY; LINE SEYFERT-1 GALAXIES; ACCRETION DISK; CYGNUS X-1; ENERGY-DISTRIBUTIONS; OPTICAL OBSERVATIONS; ASCA OBSERVATIONS; TIME VARIABILITY; DWARF NOVAE AB We analyse the scaling, of the X-ray power density spectra with the mass of the black hole in the examples of Cyg X-1 and the Seyfert I galaxy NGC 5548. We show that the high-frequency tail of the power density spectrum can be successfully used for the determination of the black hole mass. We determine the masses of the black holes in six broad-line Seyfert 1 galaxies, five narrow-line Seyfert 1 galaxies and two quasi-stellar objects (QSOs) using the available power density spectra. The proposed scaling is clearly appropriate for other Seyfert,galaxies and QSOs. In all but one of the normal Seyferts, the resulting luminosity to Eddington luminosity ratio is smaller than 0.15, with the source MCG -6-15-30 being an exception. The applicability of the same scaling to a narrow-line Seyfert 1 is less clear and there may be a systematic shift between the power spectra of NLS1 and S1 galaxies of the same mass, leading to underestimation of the black hole mass. However, both the method based on variability and the method based on spectral fitting show that those galaxies have relatively low masses and a high luminosity to Eddington luminosity ratio, supporting the view of those objects as analogues of galactic sources in their high, soft or very high state, based on the overall spectral shape. The bulge masses of their host galaxies are similar to that of normal Seyfert galaxies, so they do not follow the black hole mass-bulge mass relation for Seyfert galaxies, being evolutionarily less advanced, as suggested by Mathur. The bulge mass-black hole mass relation in our sample is consistent with being linear, with the black hole to bulge ratio similar to0.03 per cent, similar to Wandel and Laor for low-mass objects, but significantly shifted from the relation of Magorrian et al. and McLure & Dunlop. C1 Nicholas Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Czerny, B (reprint author), Nicholas Copernicus Astron Ctr, Bartycka 18, PL-00716 Warsaw, Poland. RI Czerny, Bozena/A-2363-2015 OI Czerny, Bozena/0000-0001-5848-4333 NR 108 TC 59 Z9 60 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 1 PY 2001 VL 325 IS 2 BP 865 EP 874 DI 10.1046/j.1365-8711.2001.04522.x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 465BJ UT WOS:000170568100041 ER PT J AU Gnedin, NY Abel, T AF Gnedin, NY Abel, T TI Multi-dimensional cosmological radiative transfer with a Variable Eddington Tensor formalism SO NEW ASTRONOMY LA English DT Article DE cosmology : theory; large-scale structure of universe; galaxies : formation; intergalactic medium ID IONIZING-RADIATION; GALAXY FORMATION; REIONIZATION; FEEDBACK AB We present a new approach to numerically model continuum radiative transfer based on the Optically Thin Variable Eddington Tensor (OTVET) approximation. Our method insures the exact conservation of the photon number and flux (in the explicit formulation) and automatically switches from the optically thick to the optically thin regime. It scales as N log N with the number of hydrodynamic resolution elements and is independent of the number of sources of ionizing radiation (i.e. works equally fast for an arbitrary source function). We also describe an implementation of the algorithm in a Soften Lagrangian Hydrodynamic code (SLH) and a multi-frequency approach appropriate for hydrogen and helium continuum opacities. We present extensive tests of our method for single and multiple sources in homogeneous and inhomogeneous density distributions, as well as a realistic simulation of cosmological reionization. (C) 2001 Published by Elsevier Science B.V. C1 Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Gnedin, NY (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, Campus Box 391, Boulder, CO 80309 USA. NR 16 TC 134 Z9 134 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1384-1092 J9 NEW ASTRON JI New Astron. PD AUG PY 2001 VL 6 IS 7 BP 437 EP 455 DI 10.1016/S1384-1076(01)00068-9 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 474XQ UT WOS:000171132500004 ER PT J AU Kral, P Fiurasek, J Shapiro, M AF Kral, P Fiurasek, J Shapiro, M TI Competition between electron and hole stimulated Raman passage SO PHYSICAL REVIEW A LA English DT Article ID ADIABATIC PASSAGE; LASER-PULSES; MOLECULES; STATES; TRANSITION; SYSTEMS; ATOMS AB We demonstrate an electron-hole symmetry in the method of stimulated Raman adiabatic passage (STIRAP), and point out the existence of separate electron and hole regimes in atoms and molecules. In particular, we study hole STIRAP's in the triplet states of N-2. We show that when electron and hole STIRAP's coexist, the competition between them leads to a powerful method of controlling bifurcating processes in molecular systems. C1 Weizmann Inst Sci, Dept Chem Phys, IL-76100 Rehovot, Israel. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Kral, P (reprint author), Weizmann Inst Sci, Dept Chem Phys, IL-76100 Rehovot, Israel. NR 21 TC 7 Z9 7 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2001 VL 64 IS 2 BP art. no. EP 023414 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 460FJ UT WOS:000170297300085 ER PT J AU Forrey, RC Balakrishnan, N Dalgarno, A Haggerty, MR Heller, EJ AF Forrey, RC Balakrishnan, N Dalgarno, A Haggerty, MR Heller, EJ TI Effect of quasiresonant dynamics on the predissociation of van der Waals molecules SO PHYSICAL REVIEW A LA English DT Article ID STATE POTASSIUM MOLECULES; ATOM-DIATOM SCATTERING; VIBRATIONAL PREDISSOCIATION; VANDERWAALS MOLECULES; COLLISIONS; COLD; TEMPERATURES; PHOTOASSOCIATION; RELAXATION; RESONANCES AB Rotational and vibrational distributions of zero-temperature collisional rate coefficients for atom-diatom scattering are used together with effective range theory to obtain lifetimes for predissociation. High-order indirect potential coupling in the quantum-mechanical calculation is interpreted using a simple classical picture that describes the quasiresonant dynamics of atom-diatom collisions by the conservation of classical action. The importance of closed channel thresholds in determining the structure of the distributions and the balance between momentum gap and near-resonant effects is discussed. C1 Penn State Univ, Berks Lehigh Valley Coll, Reading, PA 19610 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Harvard Univ, Dept Chem, Cambridge, MA 02138 USA. RP Forrey, RC (reprint author), Penn State Univ, Berks Lehigh Valley Coll, Reading, PA 19610 USA. NR 40 TC 19 Z9 19 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 EI 1094-1622 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2001 VL 64 IS 2 AR 022706 DI 10.1103/PhysRevA.64.022706 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 460FJ UT WOS:000170297300051 ER PT J AU Hueber, FM AF Hueber, FM TI Rotted wood-alga-fungus: the history and life of Prototaxites Dawson 1859 SO REVIEW OF PALAEOBOTANY AND PALYNOLOGY LA English DT Article; Proceedings Paper CT 16th International Botanical Congress CY AUG 01-06, 1999 CL ST LOUIS, MISSOURI SP Amer Bryolog & Lichenolog Soc DE Prototaxites; Fungi; Devonian; Canada; neotype; paleoecology AB The Devonian flora discovered and collected by W.E. Logan in 1843 remained unstudied until 1855 at which time the collections were offered to J.W. Dawson. His attention was immediately drawn to a single large specimen in the collections, which he identified and described as partially rotted wood of a conifer (Dawson, 1857). He proposed the name Prototaxites (Dawson, 1859) thereby expressing his concept of the genus. That concept remained unchallenged until Carruthers (1872) heatedly ridiculed both the name and the author and illegitimately substituted the name Nematophycus. His subjective opinion was that the fossil represented a fragment of a very large alga, like Lessonia. His classification, challenged only once (Church, 1919), persisted in all subsequent reports. Dawson remained adamant in his definition of Prototaxites until he illegitimately substituted the name Nematophyton for Prototaxites (Dawson, 1888) and denied (Dawson, in Penhallow, 1889) that he had ever classed the genus with the conifers. The names Nematophycus and Nematophyton are later synonyms of Prototaxites and, although inappropriate in connotation, Prototaxites is nomenclaturally valid. No undoubted original nor associated specimens are available for choice of a lectotype. This report has a triple purpose: (1) to name, as neotype, a recognizable specimen collected by Dawson for which the locality and stratigraphic data are known, (2) to redescribe the genus as structurally composed of three interactive forms of hyphae, i.e. large thin-walled, septate, branching, generative hyphae; large thick-walled, non-septate, skeletal hyphae; and small thin-walled, septate, branching, binding hyphae, which combine to form a gigantic, phototropic, amphigenous, perennial sporophore with saprobic nutrition, and (3) to classify it in the Kingdom Fungi. Generic synonymy with Prototaxites is proposed for Nematophycus (Carruthers, 1872). (C) 2001 Elsevier Science B.V. All rights reserved. C1 Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. RP Hueber, FM (reprint author), Smithsonian Inst, Dept Paleobiol, MRC-121, Washington, DC 20560 USA. NR 66 TC 62 Z9 71 U1 5 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0034-6667 J9 REV PALAEOBOT PALYNO JI Rev. Palaeobot. Palynology PD AUG PY 2001 VL 116 IS 1-2 SI SI BP 123 EP 158 DI 10.1016/S0034-6667(01)00058-6 PG 36 WC Plant Sciences; Paleontology SC Plant Sciences; Paleontology GA 472FD UT WOS:000170972100009 ER PT J AU Remo, JL Haubold, HJ AF Remo, JL Haubold, HJ TI NEO scientific and policy developments, 1995-2000 SO SPACE POLICY LA English DT Article AB Scientific and policy developments in the field of Near-Earth Objects (NEOs) since the UN NEO conference in 1995 are briefly outlined. Some areas of research and discovery have exhibited considerable progress while others have languished. In particular, facilities in the southern hemisphere for discovery and tracking of NEOs are inadequate. Suggestions are made both at the scientific and technical levels as well as at the policy level to provide coordinated and coherent progress in developing a long-term approach to NEO hazard mitigation. The next step should be the establishment of a panel of international scientific experts on the subject. (C) 2001 Published by Elsevier Science Ltd. C1 Harvard Smithsonian Ctr Astrophys, Planetary Sci Div, Cambridge, MA 02138 USA. UN Off Outer Space Affairs, Vienna, Austria. RP Remo, JL (reprint author), Harvard Smithsonian Ctr Astrophys, Planetary Sci Div, 60 Garden St,Mail Stop 18, Cambridge, MA 02138 USA. NR 10 TC 6 Z9 6 U1 0 U2 0 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 AUG PY 2001 VL 17 IS 3 BP 213 EP 218 DI 10.1016/S0265-9646(01)00022-4 PG 6 WC International Relations; Social Sciences, Interdisciplinary SC International Relations; Social Sciences - Other Topics GA 470AR UT WOS:000170848700008 ER PT J AU Kane, MD AF Kane, MD TI The evolutionary biology of ... everything SO SYSTEMATIC BIOLOGY LA English DT Editorial Material C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Entomol, Washington, DC 20560 USA. RP Kane, MD (reprint author), Natl Sci Fdn, Div Environm Biol, 4201 Wilson Blvd, Arlington, VA 22230 USA. NR 4 TC 1 Z9 2 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 1063-5157 J9 SYST BIOL JI Syst. Biol. PD AUG PY 2001 VL 50 IS 4 BP 468 EP 469 PG 2 WC Evolutionary Biology SC Evolutionary Biology GA 473RD UT WOS:000171061000002 PM 12116646 ER PT J AU Swofford, DL Waddell, PJ Huelsenbeck, JP Foster, PG Lewis, PO Rogers, JS AF Swofford, DL Waddell, PJ Huelsenbeck, JP Foster, PG Lewis, PO Rogers, JS TI Bias in phylogenetic estimation and its relevance to the choice between parsimony and likelihood methods SO SYSTEMATIC BIOLOGY LA English DT Article ID EVOLUTIONARY TREES; INCONSISTENCY; INFERENCE; SUCCESS; RATES; RECONSTRUCTION; CONSISTENCY; RELIABILITY; SIMULATION; SEQUENCES C1 Smithsonian Inst, Natl Museum Nat Hist, Lab Mol Systemat, Support Ctr, Suitland, MD 20746 USA. Massey Univ, Inst Mol BioSci, Palmerston North, New Zealand. Univ Rochester, Dept Biol, Rochester, NY 14627 USA. Univ Connecticut, Dept Ecol & Evolutionary Biol, Storrs, CT 06269 USA. Univ New Orleans, Dept Biol Sci, New Orleans, LA 70148 USA. RP Swofford, DL (reprint author), Nat Hist Museum, Cromwell Rd, London SW7 5BD, England. RI Huelsenbeck, John/C-6398-2013 NR 32 TC 259 Z9 264 U1 3 U2 16 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 1063-5157 J9 SYST BIOL JI Syst. Biol. PD AUG PY 2001 VL 50 IS 4 BP 525 EP 539 DI 10.1080/106351501750435086 PG 15 WC Evolutionary Biology SC Evolutionary Biology GA 473RD UT WOS:000171061000007 PM 12116651 ER PT J AU Krzywinski, J Wilkerson, RC Besansky, NJ AF Krzywinski, J Wilkerson, RC Besansky, NJ TI Toward understanding Anophelinae (Diptera, Culicidae) phylogeny: Insights from nuclear single-copy genes and the weight of evidence SO SYSTEMATIC BIOLOGY LA English DT Article DE Anopheles; biogeography; evolution; G(6)pd; mosquitoes; phylogeny; simultaneous analysis; white ID INSECT MOLECULAR SYSTEMATICS; WHITE GENE; INFERRING RELATIONSHIPS; EVOLUTIONARY DISTANCES; NUCLEOTIDE-SEQUENCES; MOSQUITOS DIPTERA; COMBINING DATA; CONGRUENCE; DROSOPHILA; MODEL AB A phylogeny of the mosquito subfamily Anophelinae was inferred from fragments of two protein-coding nuclear genes, G(6)pd (462 bp) and white (801 bp), and from a combined data set (2,136 bp) that included a portion of the mitochondrial gene ND5 and the D2 region of the ribosomal 28S gene. Sixteen species from all three anopheline genera and six Anopheles subgenera were sampled, along with six species of other mosquitoes used as an outgroup. Each of four genes analyzed individually recovered the same well-supported clades; topological incongruence was limited to unsupported or poorly supported nodes. As assessed by the incongruence length difference test, most of the conflicting signal was contributed by third codon positions. Strong structural constraints, as observed in white and G6pd, apparently had little impact on phylogenetic inference. Compared with the other genes, white provided a superior source of phylogenetic information. However, white appears to have experienced accelerated rates of evolution in few lineages, the affinities of which are therefore suspect. In combined analyses, most of the inferred relationships were well-supported and in agreement with previous studies: monophyly of Anophelinae, basal position of Chagasia, monophyly of Anopheles subgenera, and subgenera Nyssorhynchus + Kerteszia as sister taxa. The results suggested also monophyletic origin of subgenera Cellia + Anopheles, and the white gene analysis supported genus Bironella as a sister taxon to Anopheles. The present data and other available evidence suggest a South American origin of Anophelinae, probably in the Mesozoic; a rapid diversification of Bironella and basal subgeneric lineages of Anopheles, potentially associated with the breakup of Gondwanaland; and a relatively recent and rapid dispersion of subgenus Anopheles. C1 Univ Notre Dame, Dept Biol Sci, Notre Dame, IN 46556 USA. Smithsonian Inst, Museum Support Ctr, Walter Reed Biosystemat Unit, Suitland, MD 20746 USA. RP Krzywinski, J (reprint author), Univ Notre Dame, Dept Biol Sci, POB 369, Notre Dame, IN 46556 USA. EM jaroslaw.krzywinski.1@iid.edu NR 64 TC 71 Z9 75 U1 1 U2 7 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1063-5157 EI 1076-836X J9 SYST BIOL JI Syst. Biol. PD AUG PY 2001 VL 50 IS 4 BP 540 EP 556 DI 10.1080/106351501750435095 PG 17 WC Evolutionary Biology SC Evolutionary Biology GA 473RD UT WOS:000171061000008 PM 12116652 ER PT J AU de Queiroz, K Cantino, PD AF de Queiroz, K Cantino, PD TI Taxon names, not taxa, are defined SO TAXON LA English DT Editorial Material ID PHYLOGENETIC NOMENCLATURE; DEFINITIONS C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. Ohio Univ, Dept Environm & Plant Biol, Athens, OH 45701 USA. RP de Queiroz, K (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 19 TC 14 Z9 14 U1 1 U2 2 PU INT ASSOC PLANT TAXONOMY PI BERLIN PA BOTANISCHER GARTEN BOTANISCHES MUSEUM BERLIN-DAHLEM, KONIGIN-LUISE-STRABE 6-8, D-14191 BERLIN, GERMANY SN 0040-0262 J9 TAXON JI Taxon PD AUG PY 2001 VL 50 IS 3 BP 821 EP 826 DI 10.2307/1223709 PG 6 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA 475FU UT WOS:000171152300011 ER PT J AU Nicolson, DH Arculus, D AF Nicolson, DH Arculus, D TI Candidates for neotypification of Blanco's names of Philippine plants: specimens in the US National Herbarium SO TAXON LA English DT Article DE Blanco; Merrill; Philippine plants; US National Herbarium AB Evidence suggests that of the widely distributed sets of E. D. Merrill's "illustrative specimens" for F. M. Blanco's names of Philippine plants, the first, most complete, and best labelled extant set is the one at the U.S. National Herbarium. Workers considering neotypification of Blanco's plant names should give special consideration to the materials at US. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, Washington, DC 20560 USA. Natl Lib Med, Bethesda, MD 20894 USA. RP Nicolson, DH (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, Washington, DC 20560 USA. NR 12 TC 7 Z9 8 U1 0 U2 0 PU INT ASSOC PLANT TAXONOMY PI BERLIN PA BOTANISCHER GARTEN BOTANISCHES MUSEUM BERLIN-DAHLEM, KONIGIN-LUISE-STRABE 6-8, D-14191 BERLIN, GERMANY SN 0040-0262 J9 TAXON JI Taxon PD AUG PY 2001 VL 50 IS 3 BP 947 EP 954 PG 8 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA 475FU UT WOS:000171152300024 ER PT J AU Harnal, VK Spindler, R Monfort, SL Pukazhenthi, B Bird, DM Wildt, DE AF Harnal, VK Spindler, R Monfort, SL Pukazhenthi, B Bird, DM Wildt, DE TI Sperm capacitation in vitro in the Eld's deer SO THERIOGENOLOGY LA English DT Article DE spermatozoa; sperm capacitation; Eld's deer; cryopreservation ID PROTEIN-TYROSINE PHOSPHORYLATION; ACROSOME REACTION; BOVINE SPERM; PHASE-TRANSITIONS; MAMMALIAN SPERM; SEMEN EXTENDER; DOMESTIC CAT; SPERMATOZOA; INVITRO; FERTILIZATION AB Sperm capacitation was examined in the endangered Eld's deer (Cervus eldi thamin). Sperm motility and viability (percentage of sperm cells with intact membranes) were assessed in vitro over time after attempting to induce capacitation in TALP alone and TALP supplemented with calcium (10 mM CaCl2), dibutyryl cAMP (1 mM dbcAMP), or fetal calf serum (20% FCS). Sperm aliquots were evaluated at 0, 3, 6, 9, and 12 h for motility, viability, and ability to acrosome react after exposure to calcium ionophore (A23187, CI; 10 muM) or lysophosphatidylcholine (LC; 100 mug/mL). Fresh sperm aliquots in TALP + 10 mM CaCl2 exposed to CI had fewer (P < 0.05) intact acrosomes than the TALP control (TALP alone) or dbcAMP and FCS treatments after 9 h. Mean (+/- SEM) percentage of intact acrosomes of spermatozoa incubated in medium with increased CaCl2 declined (P < 0.05) from 80.2 +/- 2.6% (0 h) to 49.7 +/- 7.3% after prolonged incubation (9 h), The proportion of capacitated fresh spermatozoa was not influenced by LC treatment. Capacitation was not induced (P > 0.05) by any of the presumptive sperm capacitators after freeze-thawing. Likewise, neither CI nor LC induced the acrosome reaction (AR) in these spermatozoa, suggesting that the freeze-thawing process may have caused membrane damage. Results revealed that the supplementation of medium with CaCl2 evokes capacitation in some spermatozoa. However, Eld's deer spermatozoa appear remarkably resistant to conventional stimulators of capacitation and the AR. (C) 2001 by Elsevier Science Inc. C1 Smithsonian Inst, Conservat & Res Ctr, Natl Zool Pk, Front Royal, VA 22630 USA. McGill Univ, St Anne De Bellevue, PQ, Canada. RP Monfort, SL (reprint author), Smithsonian Inst, Conservat & Res Ctr, Natl Zool Pk, 1500 Remount Rd, Front Royal, VA 22630 USA. FU NCRR NIH HHS [KO1 RR00135] NR 43 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0093-691X J9 THERIOGENOLOGY JI Theriogenology PD AUG 1 PY 2001 VL 56 IS 3 BP 399 EP 413 DI 10.1016/S0093-691X(01)00572-6 PG 15 WC Reproductive Biology; Veterinary Sciences SC Reproductive Biology; Veterinary Sciences GA 460XJ UT WOS:000170334700003 PM 11516120 ER PT J AU Jackson, JBC Kirby, MX Berger, WH Bjorndal, KA Botsford, LW Bourque, BJ Bradbury, RH Cooke, R Erlandson, J Estes, JA Hughes, TP Kidwell, S Lange, CB Lenihan, HS Pandolfi, JM Peterson, CH Steneck, RS Tegner, MJ Warner, RR AF Jackson, JBC Kirby, MX Berger, WH Bjorndal, KA Botsford, LW Bourque, BJ Bradbury, RH Cooke, R Erlandson, J Estes, JA Hughes, TP Kidwell, S Lange, CB Lenihan, HS Pandolfi, JM Peterson, CH Steneck, RS Tegner, MJ Warner, RR TI Historical overfishing and the recent collapse of coastal ecosystems SO SCIENCE LA English DT Review ID KELP FOREST COMMUNITIES; CHELONIA-MYDAS L; CHESAPEAKE BAY; SEA OTTERS; SOUTHERN CALIFORNIA; INFECTIOUS-DISEASE; MARINE ECOSYSTEM; TROPHIC CASCADES; REEF COMMUNITY; GREEN TURTLE AB Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archeol, Balboa, Panama. Natl Ctr Ecol Anal & Synth, Santa Barbara, CA 93101 USA. Univ Florida, Archie Carr Ctr Sea Turtle Res, Gainesville, FL 32611 USA. Univ Florida, Dept Zool, Gainesville, FL 32611 USA. Univ Calif Davis, Dept Wildlife Fish & Conservat Biol, Davis, CA 95616 USA. Bates Coll, Dept Anthropol, Lewiston, ME 04240 USA. Australian Natl Univ, Ctr Resource & Environm Studies, Canberra, ACT 0200, Australia. Univ Oregon, Dept Anthropol, Eugene, OR 97403 USA. Univ Calif Santa Cruz, US Geol Survey, Santa Cruz, CA 95064 USA. James Cook Univ N Queensland, Dept Marine Biol, Ctr Coral Reef Biodivers, Townsville, Qld 4811, Australia. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. Univ N Carolina, Inst Marine Sci, Morehead City, NC 28557 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. Univ Maine, Darling Marine Ctr, Sch Marine Sci, Walpole, ME 04573 USA. Univ Calif Santa Barbara, Dept Ecol Evolut & Marine Biol, Santa Barbara, CA 93106 USA. RP Jackson, JBC (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. EM jbcj@ucsd.edu RI Pandolfi, John/A-3121-2009; Hughes, Terry/L-4721-2013; Warner, Robert/M-5342-2013; OI Pandolfi, John/0000-0003-3047-6694; Hughes, Terry/0000-0002-5257-5063; Warner, Robert/0000-0002-3299-5685; Erlandson, Jon/0000-0002-4705-4319; Bjorndal, Karen/0000-0002-6286-1901 NR 113 TC 2945 Z9 3076 U1 237 U2 2133 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 27 PY 2001 VL 293 IS 5530 BP 629 EP 638 DI 10.1126/science.1059199 PG 10 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 458PW UT WOS:000170204600040 PM 11474098 ER PT J AU Rees, M Condit, R Crawley, M Pacala, S Tilman, D AF Rees, M Condit, R Crawley, M Pacala, S Tilman, D TI Long-term studies of vegetation dynamics SO SCIENCE LA English DT Review ID TROPICAL RAIN-FORESTS; RECRUITMENT LIMITATION; PLANT DIVERSITY; SEED SIZE; VARIABLE ENVIRONMENTS; GRASSLAND PLANTS; GRAZING OPTIMIZATION; LITTER DECOMPOSITION; POPULATION-DYNAMICS; COMMUNITY STRUCTURE AB By integrating a wide range of experimental, comparative, and theoretical approaches, ecologists are starting to gain a detailed understanding of the long-term dynamics of vegetation. We explore how patterns of variation in demographic traits among species have provided insight into the processes that structure plant communities. We find a common set of mechanisms, derived from ecological and evolutionary principles, that underlie the main forces shaping systems as diverse as annual plant communities and tropical forests. Trait variation between species maintains diversity and has important implications for ecosystem processes. Hence, greater understanding of how Earth's vegetation functions wit[ likely require integration of ecosystem science with ideas from plant evolutionary, population, and community ecology. C1 Univ London Imperial Coll Sci Technol & Med, NERC, Ctr Populat Biol, Ascot SL5 7PY, Berks, England. Smithsonian Trop Res Inst, Ctr Trop Forest Sci, Unit 0948, APO, AA 34002 USA. Princeton Univ, Dept Ecol & Evolut Biol, Princeton, NJ 08544 USA. Univ Minnesota, Dept Ecol Evolut & Behav, St Paul, MN 55108 USA. RP Rees, M (reprint author), Univ London Imperial Coll Sci Technol & Med, NERC, Ctr Populat Biol, Silwood Pk, Ascot SL5 7PY, Berks, England. NR 111 TC 279 Z9 316 U1 12 U2 165 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 27 PY 2001 VL 293 IS 5530 BP 650 EP 655 DI 10.1126/science.1062586 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 458PW UT WOS:000170204600043 PM 11474101 ER PT J AU Saar, SH Cuntz, M AF Saar, SH Cuntz, M TI A search for CaII emission enhancement in stars resulting from nearby giant planets SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars : activity; stars : chromospheres; stars : late-type; planetary systems; stars : rotation ID LONGITUDINAL TUBE WAVES; SOLAR ATMOSPHERE; TIME-SERIES; AR LACERTAE; GENERATION; CONVECTION AB We present a search for periodicities (P-chr) in the chromospheric Ca II infrared triplet emission of several stars (tau Boo, 51 Peg, v And, rho (1) Cnc, rho CrB, 70 Vir and GL 876) which may be directly attributable to interaction with close-in giant planets. Activity enhancements could arise from increased non-radiative heating and dynamo action in planet-induced tidal bulges (with P-chr approximate toP(orb)/2), or from interactions between the stellar and planetary magnetic fields (with P-chr approximate toP(orb)). We compare both P-chr and the phase dependence of the activity with the planetary orbital period P-orb, the orbital phase, and models. No significant P-chr or phase dependence attributable to planets can be clearly identified. We place approximate upper limits on the amplitude of any planet-induced activity. We identify a possible stellar rotation period for GL 876, and support previous period determinations for four other stars. We discuss the results and possible directions of future research. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Texas, Dept Phys, Arlington, TX 76019 USA. RP Saar, SH (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 34 TC 17 Z9 17 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 21 PY 2001 VL 325 IS 1 BP 55 EP 59 DI 10.1046/j.1365-8711.2001.04296.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458DT UT WOS:000170178500004 ER PT J AU Pierpaoli, E Scott, D White, M AF Pierpaoli, E Scott, D White, M TI Power-spectrum normalization from the local abundance of rich clusters of galaxies SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : clusters : general; cosmology : theory; large-scale structure of Universe; X-rays : galaxies : clusters ID X-RAY-CLUSTERS; COLD DARK-MATTER; RADIAL TEMPERATURE PROFILES; LOW-DENSITY UNIVERSE; FLUX-LIMITED SAMPLE; ALL-SKY SURVEY; COSMOLOGICAL CONSTANT; MASS FUNCTION; EVOLUTION; ROSAT AB The number density of rich galaxy clusters still provides the most robust way of normalizing the power spectrum of dark matter perturbations on scales relevant to large-scale structure. We revisit this constraint in the light of several recent developments: (1) the availability of well-defined samples of local clusters with relatively accurate X-ray temperatures; (2) new theoretical mass functions for dark matter haloes, which provide a good fit to large numerical simulations; (3) more accurate mass-temperature relations from larger catalogues of hydrodynamical simulations; (4) the requirement to consider closed as well as open and flat cosmologies to obtain full multiparameter likelihood constraints for CMB and SNe studies. We present a new sample of clusters drawn from the literature and use this sample to obtain improved results on sigma (8), the normalization of the matter power spectrum on scales of 8 h(-1) Mpc, as a function of the matter density and cosmological constant in a universe with general curvature. We discuss our differences with previous work, and the remaining major sources of uncertainty. Final results on the normalization, approximately independent of power spectrum shape, can be expressed as constraints on cr at an appropriate cluster normalization scale R-Cl. We provide fitting formulas for R-Cl and sigma (R-Cl) for general cosmologies, as well as for sigma (8) as a function of cosmology and shape parameter Gamma. For flat models we find approximately sigma (8) similar or equal to (0.495 (+0.034)(-0.037)) Omega (-0.60)(M) for Gamma = 0.23, where the error bar is dominated by uncertainty in the mass-temperature relation. C1 Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Pierpaoli, E (reprint author), Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. RI White, Martin/I-3880-2015; OI White, Martin/0000-0001-9912-5070; Pierpaoli, Elena/0000-0002-7957-8993 NR 87 TC 160 Z9 160 U1 0 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 21 PY 2001 VL 325 IS 1 BP 77 EP 88 DI 10.1046/j.1365-8711.2001.04306.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458DT UT WOS:000170178500006 ER PT J AU Mazeh, T Latham, DW Goldberg, E Torres, G Stefanik, RP Henry, TJ Zucker, S Gnat, O Ofek, EO AF Mazeh, T Latham, DW Goldberg, E Torres, G Stefanik, RP Henry, TJ Zucker, S Gnat, O Ofek, EO TI Studies of multiple stellar systems - IV. The triple-lined spectroscopic system Gliese 644 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE techniques : radial velocities; binaries : spectroscopic; binaries : visual; stars : individual : Gliese 644 ID LOW-MASS STARS; ACCURATE MASSES; RADIAL-VELOCITIES; BINARY-SYSTEMS; CM-DRACONIS; 3RD STAR; COMPONENTS; CATALOG; DWARFS; TODCOR AB We present a radial velocity study of the triple-lined system Gliese 644 and derive spectroscopic elements for the inner and outer orbits with periods of 2.965 5 and 627 d. We also utilize old visual data, as well as modem speckle and adaptive optics observations, to derive a new astrometric solution for the outer orbit. These two orbits together allow us to derive masses for each of the three components in the system: M-A = 0.410 +/-0.028 (6.9 per cent), M-Ba = 0.336 +/-0.016 (4.7 per cent), and M-Bb = 0.304 +/-0.014 (4.7 per cent) M-circle dot. We suggest that the relative inclination of the two orbits is very small. Our individual masses and spectroscopic light ratios for the three M stars in the Gliese 644 system provide three points for the mass-luminosity relation near the bottom of the main sequence, where the relation is poorly determined. These three points agree well with theoretical models for solar metallicity and an age of 5 Gyr. Our radial velocities for Gliese 643 and vB 8, two common proper motion companions of Gliese 644, support the interpretation that all five M stars are moving together in a physically bound group. We discuss possible scenarios for the formation and evolution of this configuration, such as the formation of all five stars in a sequence of fragmentation events leading directly to the hierarchical configuration now observed, versus formation in a small N cluster with subsequent dynamical evolution into the present hierarchical configuration. C1 Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mazeh, T (reprint author), Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. NR 73 TC 19 Z9 19 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 21 PY 2001 VL 325 IS 1 BP 343 EP 357 DI 10.1046/j.1365-8711.2001.04419.x PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458DT UT WOS:000170178500032 ER PT J AU Meneghetti, M Yoshida, N Bartelmann, M Moscardini, L Springel, V Tormen, G White, SDM AF Meneghetti, M Yoshida, N Bartelmann, M Moscardini, L Springel, V Tormen, G White, SDM TI Giant cluster arcs as a constraint on the scattering cross-section of dark matter SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE gravitational lensing; galaxies : clusters : general; cosmology : theory; dark matter ID LUMINOUS ARCS; GALAXIES; STATISTICS; HALOS; SUBSTRUCTURE; POTENTIALS; MS-2137-23 AB We carry out ray tracing through five high-resolution simulations of a galaxy cluster, to study how its ability to produce giant gravitationally lensed arcs is influenced by the collision cross-section of its dark matter. In three cases typical dark matter particles in the cluster core undergo between 1 and 100 collisions per Hubble time; two more explore the long ('collisionless') and short ('fluid') mean free path limits. We study the size and shape distributions of arcs and compute the cross-section for producing 'extreme' arcs of various sizes. Even a few collisions per particle modifies the core structure enough to destroy the ability of the cluster to produce long, thin arcs. For larger collision frequencies the cluster must be scaled up to unrealistically large masses before it regains the ability to produce giant arcs. None of our models with self-interacting dark matter (except the 'fluid' limit) is able to produce radial arcs; even the case with the smallest scattering cross-section must be scaled to the upper limit of observed cluster masses before it produces radial arcs. Apparently the elastic collision cross-section of dark matter in clusters must be very small, below 0.1 cm(2) g(-1), to be compatible with the observed ability of clusters to produce both radial arcs and giant arcs. C1 Univ Padua, Dipartimento Astron, I-35122 Padua, Italy. Max Planck Inst Astrophys, D-85748 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Meneghetti, M (reprint author), Univ Padua, Dipartimento Astron, Vicolo Osservatorio 2, I-35122 Padua, Italy. RI Yoshida, Naoki/A-4305-2011; Bartelmann, Matthias/A-5336-2014; OI Meneghetti, Massimo/0000-0003-1225-7084 NR 39 TC 64 Z9 64 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 21 PY 2001 VL 325 IS 1 BP 435 EP 442 DI 10.1046/j.1365-8711.2001.04477.x PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 458DT UT WOS:000170178500041 ER PT J AU La Parola, V Peres, G Fabbiano, G Kim, DW Bocchino, F AF La Parola, V Peres, G Fabbiano, G Kim, DW Bocchino, F TI The ultraluminous M81 X-9 source: 20 years variability and spectral states SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; X-rays : individual (M81 X-9); X-rays : stars ID X-RAY SOURCES; GALAXY M81; ROSAT-PSPC; BLACK-HOLE; NUCLEUS; BEPPOSAX; DISCOVERY; EMISSION; DISTANCE; HOLMBERG AB The source X-9 was discovered with the Einstein Observatory in the field of M81 and is located in the dwarf galaxy Holmberg IX. X-9 has a 0.2-4.0 keV luminosity in excess of the Eddington limit for a 1 M-. compact accreting object, if it is at the same distance as Holmberg IX (3.4 Mpc). Past hypotheses on the nature of this super-Eddington source included a supernova remnant or supershell, an accreting compact object, and a background QSO. To shed light on the nature of this source, we have analyzed archival data, including the Einstein data, 23 ROSAT observations, and BeppoSAX and ASCA pointings. Our analysis reveals that most of the emission of X-9 arises from a pointlike highly variable source (0.5- 2.4 keV L-x similar to 2-8 x 10(39) ergs s(-1)) and that lower luminosity extended emission may be associated with it. The spectrum of this source changes between low- and high-intensity states, in a way reminiscent of the spectra of galactic black hole candidates. Our result strongly suggest that X-9 is not a background QSO, but a bona fide "super-Eddington" source in Ho IX, a dwarf companion of M81. C1 Dipartimento Sci Fis & Astron, Sez Astron, I-90134 Palermo, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron GS Vaiana, I-90134 Palermo, Italy. RP La Parola, V (reprint author), Dipartimento Sci Fis & Astron, Sez Astron, Piazza Parlamento 1, I-90134 Palermo, Italy. OI Bocchino, Fabrizio/0000-0002-2321-5616; La Parola, Valentina/0000-0002-8087-6488 NR 53 TC 62 Z9 62 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 JUL 20 PY 2001 VL 556 IS 1 BP 47 EP 58 DI 10.1086/321563 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 460PN UT WOS:000170317900006 ER PT J AU Fiore, F Pellegrini, S Matt, G Antonelli, LA Comastri, A della Ceca, R Giallongo, E Mathur, S Molendi, S Siemiginowska, A Trinchieri, G Wilkes, B AF Fiore, F Pellegrini, S Matt, G Antonelli, LA Comastri, A della Ceca, R Giallongo, E Mathur, S Molendi, S Siemiginowska, A Trinchieri, G Wilkes, B TI The BeppoSAX view of the X-ray active nucleus of NGC 4258 SO ASTROPHYSICAL JOURNAL LA English DT Article ID ADVECTION-DOMINATED ACCRETION; GALACTIC NUCLEI; NGC-4258; GALAXIES; EMISSION; GAS; NGC4258; DISK AB BeppoSAX observed the Seyfert 1.9 galaxy NGC 4258 in 1998 December, when its 2-10 keV luminosity was about 10(41) ergs s(-1). Large amplitude (100%) variability is observed in the 3-10 keV band on timescales of a few tens of thousands of seconds, while variability of similar to 20% is observed on timescales as short as 1 hr. The nuclear component is visible above 2 keV only, being obscured by a column density of (9.5 +/- 1.2) x 10(22) cm(-2); this component is detected at up to 70 keV with a signal-to-noise ratio of greater than or similar to3 and with a steep power-law energy spectral index of alpha (E) = 1.11 +/- 0.14. Bremstrahlung emission for the 2-70 keV X-ray luminosity, as expected in advection-dominated accretion flow models with strong winds, is ruled out by the data. The ratio between the nuclear radio (22 GHz) luminosity and the X-ray (5 keV) luminosity is consistent with that of radio-quiet quasars and Seyfert galaxies. X-ray variability, spectral shape, and radio/X-ray and near-IR/X-ray luminosity ratios suggest that the nucleus of NGC 4258 could be a scaled down version of a Seyfert nucleus and that the X-ray nuclear luminosity can be explained in terms of Comptonization in a hot corona. The soft (E less than or similar to 2 keV) X-ray emission is complex. There are at least two thermal-like components with temperatures of 0.6 +/- 0.1 keV and greater than or similar to1.3 keV. The cooler (L0.1-2.4 keV similar to 10(40) ergs s(-1)) component is probably associated with the jet, resolved in X-rays by the ROSAT HRI (Cecil et al. 1994). The luminosity of the second component, which can be modeled equally well by an unobscured power-law model with alpha (E) = 0.2(-0.2)(+0.8) is L0.1-2.4 (keV) similar to keV similar to7 x 10(39) ergs s(-1), consistent with that expected from discrete X-ray sources (binaries and supernova remnants) in the host galaxy. Observations of NGC 4258 and other maser active galactic nuclei (AGNs) show strong nuclear X-ray absorption. We propose that this large column of gas might be responsible for shielding the regions of water maser emission from X-ray illumination. So a large column density absorbing gas may be a necessary property of masing AGNs. C1 Osserv Astron Roma, I-00044 Monte Porzio Catone, Italy. BeppoSAX Sci Data Ctr, I-00131 Rome, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy. Univ Roma Tre, Dipartimento Fis, I-00146 Rome, Italy. Osservatorio Astron Bologna, I-40127 Bologna, Italy. Osserv Astron Brera, I-20121 Milan, Italy. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. CNR, IFC, I-20133 Milan, Italy. RP Fiore, F (reprint author), Osserv Astron Roma, Via Frascati 33, I-00044 Monte Porzio Catone, Italy. RI Comastri, Andrea/O-9543-2015; OI Comastri, Andrea/0000-0003-3451-9970; Giallongo, Emanuele/0000-0003-0734-1273; Wilkes, Belinda/0000-0003-1809-2364; Molendi, Silvano/0000-0002-2483-278X; Fiore, Fabrizio/0000-0002-4031-4157 NR 44 TC 21 Z9 21 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2001 VL 556 IS 1 BP 150 EP 157 DI 10.1086/321530 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 460PN UT WOS:000170317900016 ER PT J AU Kalogera, V Narayan, R Spergel, DN Taylor, JH AF Kalogera, V Narayan, R Spergel, DN Taylor, JH TI The coalescence rate of double neutron star systems SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; gravitational lensing; stars : neutron ID GALAXY REDSHIFT SURVEY; BINARY PULSAR SYSTEM; GAMMA-RAY BURSTS; LUMINOSITY FUNCTION; RADIO PULSARS; GRAVITATIONAL-RADIATION; COMPACT OBJECTS; SUPERNOVA KICKS; GALACTIC DISK; PSR B1913+16 AB We estimate the coalescence rate of close binaries with two neutron stars (NS) and discuss the prospects for the detection of NS-NS inspiral events by ground-based gravitational-wave observatories, such as LIGO. We derive the Galactic coalescence rate using the observed sample of close NS-NS binaries (PSR B1913+16 and PSR B1534+12) and examine in detail each of the sources of uncertainty associated with the estimate. Specifically, we investigate (1) the dynamical evolution of NS-NS binaries in the Galactic potential and the vertical scale height of the population, (2) the pulsar lifetimes, (3) the effects of the faint end of the radio pulsar luminosity function and their dependence on the small number of observed objects, (4) the beaming fraction, and (5) the extrapolation of the Galactic rate to extragalactic distances expected to be reachable by LIGO. We find that the dominant source of uncertainty is the correction factor (up to similar or equal to 200) for faint (undetectable) pulsars. All other sources are much less important, each with uncertainty factors smaller than 2. Despite the relatively large uncertainty, the derived coalescence rate is consistent with previously derived upper limits, and is more accurate than rates obtained from population studies. We obtain a most conservative lower limit that the detection rate by LIGO II of about 2 events per year. Our upper limit on the rate is between 300 and 1000 events per year. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Inst Adv Studies, Princeton, NJ 08540 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Princeton Univ, Joseph Henry Labs, Princeton, NJ 08544 USA. RP Kalogera, V (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM vkalogera@cfa.harvard.edu; rnarayan@cfa.harvard.edu; dns@astro.princeton.edu; joe@pulsar.princeton.edu RI Spergel, David/A-4410-2011; OI Narayan, Ramesh/0000-0002-1919-2730 NR 85 TC 117 Z9 117 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 JUL 20 PY 2001 VL 556 IS 1 BP 340 EP 356 DI 10.1086/321583 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 460PN UT WOS:000170317900029 ER PT J AU Mein, N Schmieder, B DeLuca, EE Heinzel, P Mein, P Malherbe, JM Staiger, J AF Mein, N Schmieder, B DeLuca, EE Heinzel, P Mein, P Malherbe, JM Staiger, J TI A study of hydrogen density in emerging flux loops from a coordinated Transition Region and Coronal Explorer and Canary Islands observation campaign SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : chromosphere; Sun : corona; Sun : magnetic fields; Sun : UV radiation ID VARIABLE SOURCE FUNCTION; H-ALPHA STRUCTURES; FINE-STRUCTURE; CLOUD MODEL; PHYSICAL PARAMETERS; ABSORPTION FEATURES; SOLAR; PROMINENCES; FILAMENTS; SPECTRUM AB During an international ground-based campaign in the Canary Islands coordinated with space instruments (i.e., Transition Region and Coronal Explorer [TRACE]), we observed an active region on 1998 September 10 with high spatial and temporal resolution. New emerging flux in the central part of the active region was observed in magnetograms of the Swedish Vacuum Solar Telescope, La Palma. Emerging loops (arch-filament systems [AFSs]) are well developed in H alpha and Ca II according to the observations made at the Vacuum Tower Telescope (VIT) and THEMIS telescope in Tenerife with the Multichannel Subtractive Double Pass (MSDP) spectrographs. The TRACE images obtained at 171 and 195 Angstrom show low-emission regions that are easily identified as the individual AFS. They are due to absorption by hydrogen and helium continua in the cool filament plasma. We compare two techniques of measuring the hydrogen density in the cool dense fibrils of AFSs. The first method based on TRACE observations derived the neutral hydrogen column density of the plasma absorbing coronal lines. The second one using H alpha line profiles provided by the MSDP spectrographs is based on the cloud model. The results are consistent. We derive also electron density values using H alpha lines that are in good agreement with those derived from the 8542 Angstrom Ca II line observed with THEMIS (Mein et al.). The three types of observations (TRACE, VTT, THEMIS) are well complementary: absorption of coronal lines giving a good approximation for the maximum value of the neutral hydrogen column density, the H alpha line giving a good determination of n(e), and the 8542 Angstrom Ca II line a good determination of the electronic temperature. C1 Observ Paris, Meudon Sect, F-92195 Meudon, France. Inst Theoret Astrophys, N-0315 Oslo, Norway. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic. Kiepenheuer Inst Sonnenphys, D-79104 Freiburg, Germany. RP Mein, N (reprint author), Observ Paris, Meudon Sect, F-92195 Meudon, France. RI Heinzel, Petr/G-9014-2014; DeLuca, Edward/L-7534-2013 OI DeLuca, Edward/0000-0001-7416-2895 NR 32 TC 34 Z9 34 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2001 VL 556 IS 1 BP 438 EP 451 DI 10.1086/321488 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 460PN UT WOS:000170317900039 ER PT J AU Marengo, M Karovska, M Fazio, GG Hora, JL Hoffmann, WF Dayal, A Deutsch, LK AF Marengo, M Karovska, M Fazio, GG Hora, JL Hoffmann, WF Dayal, A Deutsch, LK TI Mid-infrared observations of the Mira circumstellar environment SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; circumstellar matter; infrared : stars; stars : individual (o Ceti) ID PROTOPLANETARY NEBULA CANDIDATES; O-CETI; DUST; DISTRIBUTIONS; ENVELOPES; EMISSION; CATALOG; CO AB This Letter presents results from high angular resolution mid-IR imaging of the Mira AB circumbinary environment using the Mid-InfraRed Array Camera MIRAC3 at the NASA Infrared Telescope Facility. We resolved the dusty circumstellar envelope at 9.8, 11.7, and 18 mum around Mira A (o Ceti) and measured the size of the extended emission. Strong deviations from spherical symmetry are detected in the images of the Mira AB system, including possible dust clumps in the direction of the companion (Mira B). These observations suggest that Mira B plays an active role in shaping the morphology of the circumstellar environment of Mira A as it evolves toward the planetary nebula phase. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. KLA Tencor Corp, San Jose, CA 94134 USA. Boston Univ, Dept Astron, CAS 519, Boston, MA 02215 USA. RP Marengo, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Hora, Joseph/0000-0002-5599-4650 NR 25 TC 19 Z9 19 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 JUL 20 PY 2001 VL 556 IS 1 BP L47 EP L50 DI 10.1086/322737 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 460PQ UT WOS:000170318100011 ER PT J AU Schlegel, EM AF Schlegel, EM TI Chandra observations of SN 1999gi and the X-ray emission of Type II-P supernovae SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : spiral; supernovae : individual (SN 1999gi, SN 1999em); X-rays : galaxies ID OUTBURST; ORIGIN; LINES AB We report on the probable X-ray detection, using the Chandra X-Ray Observatory, of the Type II-plateau (II-P) supernova SN 1999gi in the spiral galaxy NGC 3184. A faint source is located within 0."4 of the supernova's optical position. The inferred luminosity is similar to1 x 10(37) ergs s(-1) in the 0.5-10 keV band for an adopted 1 keV thermal bremsstrahlung spectrum. The luminosity from SN 1999gi is very similar to that inferred from the Chandra detection of the Type II-P SN 1999em in NGC 1637 for which we extracted data from the Chandra archive. We suggest that Type II-P supernovae show X-rays initially at outburst, subsequently fade, and are not significant X-ray emitters prior to the remnant stage. C1 Harvard Smithsonian Ctr Astrophys, High Energy Astrophys Div, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, High Energy Astrophys Div, 60 Garden St, Cambridge, MA 02138 USA. NR 32 TC 18 Z9 18 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 JUL 20 PY 2001 VL 556 IS 1 BP L25 EP L28 DI 10.1086/322269 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 460PQ UT WOS:000170318100006 ER PT J AU Wood, BE Karovska, M Hack, W AF Wood, BE Karovska, M Hack, W TI Detection of H-2 emission from Mira B in ultraviolet spectra from the Hubble Space Telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : individual (o Ceti); stars : winds, outflows; ultraviolet : stars ID IMAGING SPECTROGRAPH; O-CETI; ACCRETION; ENVELOPE; SYSTEM; LINES; WINDS; CO AB We present ultraviolet spectra of Mira's companion star from the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope (HST). The companion is generally assumed to be a white dwarf surrounded by an accretion disk fed by Mira's wind, which dominates the UV emission from the system. The STIS UV spectrum is dominated by numerous, narrow H-2 lines fluoresced by H I Ly alpha, which were not detected in any of the numerous observations of Mira B by the International Ultraviolet Explorer (IUE). The high-temperature lines detected by IUE (e.g., C IV lambda 1550) still exist in the STIS spectrum but with dramatically lower fluxes. The continuum fluxes in the STIS spectra are also much lower, being more than an order of magnitude lower than ever observed by IUE and also an order of magnitude lower than fluxes observed in more recent HST Faint Object Camera objective prism spectra from 1995. Thus, the accretion rate onto Mira B was apparently much lower when STIS observed the star, and this change altered the character of Mira B's UV spectrum. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Wood, BE (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 24 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 JUL 20 PY 2001 VL 556 IS 1 BP L51 EP L54 DI 10.1086/322871 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 460PQ UT WOS:000170318100012 ER PT J AU Emry, RJ Korth, WW AF Emry, RJ Korth, WW TI Douglassciurus, new name for Douglassia Emry and Korth, 1996, not Douglassia Bartsch, 1934 (vol 16, pg 775, 1996) SO JOURNAL OF VERTEBRATE PALEONTOLOGY LA English DT Correction C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. Rochester Inst Vertebrate Paleontol, Rochester, NY 14610 USA. RP Emry, RJ (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. NR 4 TC 8 Z9 8 U1 2 U2 2 PU SOC VERTEBRATE PALEONTOLOGY PI NORTHBROOK PA 60 REVERE DR, STE 500, NORTHBROOK, IL 60062 USA SN 0272-4634 J9 J VERTEBR PALEONTOL JI J. Vertebr. Paleontol. PD JUL 20 PY 2001 VL 21 IS 2 BP 400 EP 400 DI 10.1671/0272-4634(2001)021[0400:DNNFDE]2.0.CO;2 PG 1 WC Paleontology SC Paleontology GA 456XR UT WOS:000170108500017 ER PT J AU Stanley, JD Goddio, F Schnepp, G AF Stanley, JD Goddio, F Schnepp, G TI Nile flooding sank two ancient cities - Sediment failure caused these riverbank sites to drown over 1,200 years ago. SO NATURE LA English DT Article C1 Smithsonian Inst, Natl Museum Nat Hist, Deltas Global Change Program, Washington, DC 20560 USA. Inst European Archeol Sous Marine, F-70005 Paris, France. RP Stanley, JD (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Deltas Global Change Program, Washington, DC 20560 USA. NR 11 TC 13 Z9 13 U1 2 U2 5 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 19 PY 2001 VL 412 IS 6844 BP 293 EP 294 DI 10.1038/35085628 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 453LW UT WOS:000169918200034 PM 11460151 ER PT J AU Palmer, PI Jacob, DJ Chance, K Martin, RV Spurr, RJD Kurosu, TP Bey, I Yantosca, R Fiore, A Li, QB AF Palmer, PI Jacob, DJ Chance, K Martin, RV Spurr, RJD Kurosu, TP Bey, I Yantosca, R Fiore, A Li, QB TI Air mass factor formulation for spectroscopic measurements from satellites: Application to formaldehyde retrievals from the Global Ozone Monitoring Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GOME; HYDROCARBONS; COMBUSTION; SIMULATION; CHEMISTRY; IMPACT; MODELS; NOX AB We present a new formulation for the air mass factor (AMF) to convert slant column measurements of optically thin atmospheric species from space into total vertical columns. Because of atmospheric scattering, the AMF depends on the vertical distribution of the species. We formulate the AMF as the integral of the relative vertical distribution (shape factor) of the species over the depth of the atmosphere, weighted by altitude-dependent coefficients (scattering weights) computed independently from a radiative transfer model. The scattering weights are readily tabulated, and one can then obtain the AMF for any observation scene by using shape factors from a three dimensional (3-D) atmospheric chemistry model for the period of observation. This approach subsequently allows objective evaluation of the 3-D model with the observed vertical columns, since the shape factor and the vertical column in the model represent two independent pieces of information. We demonstrate the AMF method by using slant column measurements of formaldehyde at 346 nm from the Global Ozone Monitoring Experiment satellite instrument over North America during July 1996. Shape factors are computed with the Global Earth Observing System CHEMistry (GEOS-CHEM) global 3-D model and are checked for consistency with the few available aircraft measurements. Scattering weights increase by an order of magnitude from the surface to the upper troposphere. The AMFs are typically 20-40% less over continents than over the oceans and are approximately half the values calculated in the absence of scattering. Model-induced errors in the AMF are estimated to be similar to 10%. The GEOS-CHEM model captures 50% and 60% of the variances in the observed slant and vertical columns, respectively. Comparison of the simulated and observed vertical columns allows assessment of model bias. 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. RP Palmer, PI (reprint author), Harvard Univ, Div Engn & Appl Sci, Pierce Hall,29 Oxford St, Cambridge, MA 02138 USA. RI Martin, Randall/A-2051-2008; Palmer, Paul/F-7008-2010; Martin, Randall/C-1205-2014; Yantosca, Robert/F-7920-2014; Chem, GEOS/C-5595-2014; OI Martin, Randall/0000-0003-2632-8402; Yantosca, Robert/0000-0003-3781-1870; Chance, Kelly/0000-0002-7339-7577 NR 26 TC 159 Z9 159 U1 4 U2 22 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 16 PY 2001 VL 106 IS D13 BP 14539 EP 14550 DI 10.1029/2000JD900772 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 453EQ UT WOS:000169903900026 ER PT J AU Lukin, MD Fleischhauer, M Cote, R Duan, LM Jaksch, D Cirac, JI Zoller, P AF Lukin, MD Fleischhauer, M Cote, R Duan, LM Jaksch, D Cirac, JI Zoller, P TI Dipole blockade and quantum information processing in mesoscopic atomic ensembles SO PHYSICAL REVIEW LETTERS LA English DT Article ID FROZEN RYDBERG GAS; ENTANGLEMENT; COMPUTATION; STORAGE; LIGHT AB We describe a technique for manipulating quantum information stored in collective states of mesoscopic ensembles. Quantum processing is accomplished by optical excitation into states with strong dipole-dipole interactions. The resulting "dipole blockade" can be used to inhibit transitions into all but singly excited collective states. This can be employed for a controlled generation of collective atomic spin states as well as nonclassical photonic states and for scalable quantum logic gates. An example involving a cold Rydberg gas is analyzed. C1 Harvard Smithsonian Ctr Astrophys, ITAMP, Cambridge, MA 02138 USA. Univ Kaiserslautern, Fachbereich Phys, D-67663 Kaiserslautern, Germany. Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Univ Innsbruck, Inst Theoret Phys, A-6020 Innsbruck, Austria. RP Lukin, MD (reprint author), Harvard Smithsonian Ctr Astrophys, ITAMP, 60 Garden St, Cambridge, MA 02138 USA. RI Jaksch, Dieter/F-1964-2010; Fleischhauer, Michael/G-6716-2011; Zoller, Peter/O-1639-2014 OI Zoller, Peter/0000-0003-4014-1505 NR 28 TC 753 Z9 767 U1 6 U2 70 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 16 PY 2001 VL 87 IS 3 AR 037901 DI 10.1103/PhysRevLett.87.037901 PG 4 WC Physics, Multidisciplinary SC Physics GA 454UF UT WOS:000169989600051 PM 11461592 ER PT J AU Maslakova, SA Norenburg, JL AF Maslakova, SA Norenburg, JL TI Phylogenetic study of pelagic nemerteans (Pelagica, Polystilifera) SO HYDROBIOLOGIA LA English DT Article; Proceedings Paper CT 5th International Conference on Nemertean Biology CY JUN 12-16, 2000 CL ALCALA HENARES, SPAIN SP Univ Alcala DE pelagic nemertean; phylogeny; systematics; classification; cladistic analysis ID CLADISTIC CLASSIFICATION; PHYLUM NEMERTEA; HOPLONEMERTEANS; SYSTEMATICS; GENERA AB Pelagic polystiliferous nemerteans, often referred to as Pelagica, represent one of the most enigmatic groups of nemerteans. The group includes 98 valid species assorted into 41 genera and 3-11 families, depending on the classification. Pelagica inhabit the water column of the world oceans, occupying depths from several hundred to several thousand meters. As is the case with most meso- or bathypelagic soft-bodied animals, specimens are few and numerous difficulties are associated with obtaining and preserving them, resulting in incomplete descriptions and, therefore, an obscure classification. Most genera and families of pelagic nemerteans are based upon unique combinations of two or three characters. Here, we present results of the first cladistic analysis of pelagic nemertean phylogeny. The analysis is based on morphological character data available from the primary literature and personal observations. A large percentage of missing entries in the data (21.5%), due to incompleteness of descriptions, results in a large number of maximum parsimonious cladograms, which translates into a drastic lack of resolution on the strict consensus tree. Traditional families supported by the cladistic analysis are Armaueriidae Brinkmann, 1917 and Pelagonemertidae (sensu Korotkevitsch, 1955). We propose a new diagnosis for Armaueriidae and discuss morphological characters traditionally used in pelagic nemertean classification. A few potentially informative characters are suggested for greater attention in future studies of specimens. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. George Washington Univ, Dept Biol Sci, Washington, DC 20052 USA. RP Maslakova, SA (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RI Norenburg, Jon/K-3481-2015 OI Norenburg, Jon/0000-0001-7776-1527 NR 37 TC 9 Z9 11 U1 0 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD JUL 15 PY 2001 VL 456 BP 111 EP 132 DI 10.1023/A:1013048419113 PG 22 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 511CR UT WOS:000173247500011 ER PT J AU Roe, P Norenburg, JL AF Roe, P Norenburg, JL TI Morphology and taxonomic distribution of a newly discovered feature, postero-lateral glands, in pelagic nemerteans SO HYDROBIOLOGIA LA English DT Article; Proceedings Paper CT 5th International Conference on Nemertean Biology CY JUN 12-16, 2000 CL ALCALA HENARES, SPAIN SP Univ Alcala DE pelagic nemertean; epidermal glands; morphology; taxonomy ID ZOOPLANKTON AB A variety of pelagic nemerteans from our collections off California and Hawaii between 1992 and 1997 have a pair of epidermal structures, usually visible on the intact specimens, located on the ventro-lateral margins near the caudal end of the body. The only previous reports of similar structures from pelagic or any other nemerteans are for two species of the genus Plotonemertes. Histological serial sections of at least one specimen from each of about 16 morpho-species demonstrate that these are specialized glandular regions of the epidermis, which we broadly term postero-lateral glands. The objects of this study are to describe these glands at the level of light microscopy and to consider their systematic implications and possible functions. Most of the glands consist of two more or less spatially segregated types of secretory cells. One type is usually at the anterior end of the gland and resembles typical mucous goblet cells. The other type usually is the more abundant, and resembles a nemertean serous cell, with secretion that probably is relatively proteinaceous. The glands of one of the Plotonemertes specimens have two additional types of secretory cells that are relatively abundant. This study reports on postero-lateral glands from 30 specimens: three specimens of Plotonemertes in the family Protopelagonemertidae, 18 in at least three genera of the family Pelagonemertidae, six in the monotypic family Balaenanemertidae, and three of Proarmaueria in the family Armaueriidae. The glands are relatively large, with large quantities of secretory vesicles, indicating that they must be of considerable importance to the animals. However, neither structure nor location offer self-evident clues to function of these glands. We also report on different forms of regional specialization in the epidermis of Crassonemertes and Nectonemertes, both of which lack postero-lateral glands. C1 Calif State Univ Stanislaus, Dept Biol Sci, Turlock, CA 95382 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Roe, P (reprint author), Calif State Univ Stanislaus, Dept Biol Sci, 801 W Monte Vista Ave, Turlock, CA 95382 USA. RI Norenburg, Jon/K-3481-2015 OI Norenburg, Jon/0000-0001-7776-1527 NR 15 TC 3 Z9 3 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD JUL 15 PY 2001 VL 456 BP 133 EP 144 DI 10.1023/A:1013008723656 PG 12 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 511CR UT WOS:000173247500012 ER PT J AU Envall, M Norenburg, JL AF Envall, M Norenburg, JL TI Morphology and systematics in mesopsammic nemerteans of the genus Ototyphlonemertes (Nemertea, Hoplonemertea, Ototyphlonemertidae) SO HYDROBIOLOGIA LA English DT Article; Proceedings Paper CT 5th International Conference on Nemertean Biology CY JUN 12-16, 2000 CL ALCALA HENARES, SPAIN SP Univ Alcala DE Nemertea; Ototyphlonemertes; morphology; phylogenetics; phylogenetic key; phylomorph ID INTERSTITIAL NEMERTEANS; MONOSTILIFERA AB Interstitial nemerteans of the genus Ototyphlonemertes are difficult to organize into traditional morphospecies. They occur in a multitude of slightly different local varieties that form a seemingly continuous morphological cline. In this paper, we summarize most published morphological data on the group, plus 73 new records of geographic varieties from the Mediterranean Sea in the East to the Sea of Japan in the West. We summarize morphological variation, partition traits into character and character states, propose a standardized protocol for examination of live specimens and discuss the phylogenetic structure of the group. The phylogenetic discussion leads to a hypothesis that partitions all varieties (including the established species) into six groups. These are the smallest morphologically homogenous sets of varieties (corresponding to traditional morphospecies) we can diagnose on phylogenetically reliable traits. Variation within the groups appears to be unreliable phylogenetic markers that may distinguish ecological forms rather than relatedness. However, we distinguish four of the groups by combinations of two traits, one apomorphy for a more inclusive group and one plesiomorphy, and the remaining two by one trait each that may be either a unique plesiomorphy or an apomorphy depending on the rooting, and most of them may thus join paraphyletic groups of cryptic monophyletic units. We call this kind of group phylomorph and name them the Duplex-, Pallida-, Cirrula-, Fila, Lactea- and Macintoshi-morph (referring to the first established species within each group, i.e. Ototyphlonemertes duplex, O. pallida, O. cirrula, O. fila, O. lactea and O. macintoshi respectively). The phylogenetic scheme provides a simple tool to allocate geographical varieties to a group of possible 'species' and a phylogenetic null-hypothesis for further tests with genetic data. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Envall, M (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RI Norenburg, Jon/K-3481-2015 OI Norenburg, Jon/0000-0001-7776-1527 NR 9 TC 11 Z9 14 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD JUL 15 PY 2001 VL 456 BP 145 EP 163 DI 10.1023/A:1013029310452 PG 19 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 511CR UT WOS:000173247500013 ER PT J AU Schwartz, ML Norenburg, JL AF Schwartz, ML Norenburg, JL TI Can we infer heteronemertean phylogeny from available morphological data? SO HYDROBIOLOGIA LA English DT Article; Proceedings Paper CT 5th International Conference on Nemertean Biology CY JUN 12-16, 2000 CL ALCALA HENARES, SPAIN SP Univ Alcala DE Nemertea; Heteronemertea; phylogeny; morphology ID NEMERTEANS; NEMERTINI; MICRURA; GEN AB This study uses morphological data from the primary literature to make a first pass at a cladistic analysis of the order Heteronemertea, which includes about one-third of the accepted species of the phylum Nemertea. This produced numerous trees and almost completely unresolved consensus trees. We conclude that this stems from imprecise and inadequate taxonomic descriptions of species and their morphological features, resulting in a limited number of characters and extensive homoplasy. The analyses neither support previously proposed ad hoc hypotheses of internal grouping nor do they propose robust new hypotheses. Rather, the analyses indicate that morphology-based cladistic studies of heteronemerteans will require very extensive, critical comparative study of heteronemertean morphological features. Re-examination of type material and common species appears to be the most fruitful approach to developing a clade-based classification of heteronemerteans. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. George Washington Univ, Dept Biol, Washington, DC 20052 USA. RP Schwartz, ML (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RI Norenburg, Jon/K-3481-2015 OI Norenburg, Jon/0000-0001-7776-1527 NR 17 TC 21 Z9 23 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD JUL 15 PY 2001 VL 456 BP 165 EP 174 DI 10.1023/A:1013093629108 PG 10 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 511CR UT WOS:000173247500014 ER PT J AU Zhu, C Balakrishnan, N Dalgarno, A AF Zhu, C Balakrishnan, N Dalgarno, A TI Vibrational relaxation of CO in ultracold He-3 collisions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTERACTION ENERGY SURFACE; ATOM-MOLECULE COLLISIONS; INELASTIC-COLLISIONS; COORDINATE DEPENDENCE; SCATTERING LENGTHS; DIATOM COLLISIONS; GAS-PHASE; DEACTIVATION; PHOTOASSOCIATION; TEMPERATURES AB We present results of quantum mechanical scattering calculations on the vibrational relaxation of CO induced by collisions with He-3 at ultracold temperatures and compare them with the corresponding results for the He-4-CO system. The low energy cross sections are controlled by shape resonances supported by the van der Waals well. For a thermal rotational population the cross sections for the quenching of the v=1 vibrational level are larger for He-3 than for He-4 collisions. Because of the absence of a Feshbach resonance, the cross sections at low energies for the quenching of the j=1 rotational level are much smaller than those for He-4-CO. Very good agreement is found for the rate coefficients for the vibrational relaxation of the v=1 level with the measurement data that are available at temperatures above 35 K. There are small discrepancies between the calculated rate coefficients with earlier calculations for the relaxation of the v=1 vibrational level, similar to those found for He-4-CO collisions, but the discrepancies tend to be larger with decrease of temperature. (C) 2001 American Institute of Physics. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Zhu, C (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 29 TC 28 Z9 28 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 15 PY 2001 VL 115 IS 3 BP 1335 EP 1339 DI 10.1063/1.1379581 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 451AB UT WOS:000169776100022 ER PT J AU Campos, E Manning, RB AF Campos, E Manning, RB TI Authorship and diagnosis of the genus Arcotheres Manning, 1993 (Crustacea : Brachyura : Pinnotheridae) SO RAFFLES BULLETIN OF ZOOLOGY LA English DT Article DE Crustacea; Pinnotheridae; genus Arcotheres; Diagnosis; Authorship AB The pinnotherid generic name Arcotheres was first published by Burger (1895) as a synonym of Pinnotheres Bose, 1802, and thus is unavailable. The generic name must be attributed to Manning (1993), who first recognized it as a genus distinct from Pinnotheres. The type species is Pinnotheres palaensis Burger, 1895. Nine other species of Pinnotheres named by Burger in 1895 are transferred to Arcotheres. Members of the genus, inhabitants of bivalves, are restricted to the Indo-Pacific region. C1 Univ Autonoma Baja California, Fac Ciencias, Ensenada, Baja California, Mexico. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Campos, E (reprint author), Univ Autonoma Baja California, Fac Ciencias, Apartado Postal 2300, Ensenada, Baja California, Mexico. NR 6 TC 5 Z9 5 U1 0 U2 0 PU NATL UNIV SINGAPORE, SCHOOL BIOLOGICAL SCIENCES PI SINGAPORE PA DEPT ZOOLOGY, KENT RIDGE, SINGAPORE 0511, SINGAPORE SN 0217-2445 J9 RAFFLES B ZOOL JI Raffles Bull. Zool. PD JUL 15 PY 2001 VL 49 IS 1 BP 167 EP 170 PG 4 WC Zoology SC Zoology GA 461XX UT WOS:000170390100016 ER PT J AU Melnick, GJ Neufeld, DA Ford, KES Hollenbach, DJ Ashby, MLN AF Melnick, GJ Neufeld, DA Ford, KES Hollenbach, DJ Ashby, MLN TI Discovery of water vapour around IRC+10216 as evidence for comets orbiting another star SO NATURE LA English DT Article ID WAVE-ASTRONOMY-SATELLITE; SUBMILLIMETER; MILLIMETER; MOLECULES; SPECTRUM; LINES; HCN AB Since 1995, planets with masses comparable to that of Jupiter have been discovered around approximately 60 stars(1). These planets have not been seen directly, but their presence has been inferred from the small reflex motions that they gravitationally induce on the star they orbit; these motions result in small periodic wavelength shifts in the stellar spectrum. The presence of analogues of the smaller bodies in our Solar System cannot, however, be determined using this technique, because the induced reflex motions are too small-so an alternative approach is needed. Here we report the observation of circumstellar water vapour around the ageing carbon star IRC+10216; water is not expected in measurable quantities around such a star. The only plausible explanation for this water is that the recent evolution of IRC+10216, which has been accompanied by a prodigious increase in its luminosity, is causing the vaporization of a collection of orbiting icy bodies-a process considered in an earlier theoretical study(2). C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Melnick, GJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 18 TC 97 Z9 98 U1 0 U2 2 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 12 PY 2001 VL 412 IS 6843 BP 160 EP 163 DI 10.1038/35084024 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 451AJ UT WOS:000169778700044 PM 11449266 ER PT J AU Gladman, B Kavelaars, JJ Holman, M Nicholson, PD Burns, JA Hergenrother, CW Petit, JM Marsden, BG Jacobson, R Gray, W Grav, T AF Gladman, B Kavelaars, JJ Holman, M Nicholson, PD Burns, JA Hergenrother, CW Petit, JM Marsden, BG Jacobson, R Gray, W Grav, T TI Discovery of 12 satellites of Saturn exhibiting orbital clustering SO NATURE LA English DT Article ID JOVIAN-SATELLITES; ASTEROIDS; URANUS; STABILITY; CAPTURE; ORIGIN; PHOEBE; SYSTEM; MOONS AB The giant planets in the Solar System each have two groups of satellites. The regular satellites move along nearly circular orbits in the planet's orbital plane, revolving about it in the same sense as the planet spins. In contrast, the so-called irregular satellites are generally smaller in size and are characterized by large orbits with significant eccentricity, inclination or both. The differences in their characteristics suggest that the regular and irregular satellites formed by different mechanisms: the regular satellites are believed to have formed in an accretion disk around the planet, like a miniature Solar System, whereas the irregulars are generally thought to be captured planetesimals(1). Here we report the discovery of 12 irregular satellites of Saturn, along with the determinations of their orbits. These orbits, along with the orbits of irregular satellites of Jupiter and Uranus, fall into groups on the basis of their orbital inclinations. We interpret this result as indicating that most of the irregular moons are collisional remnants of larger satellites that were fragmented after capture, rather than being captured independently. C1 Observ Cote Azur, F-06304 Nice 4, France. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Project Pluto, Bowdoinham, ME 04008 USA. Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. RP Gladman, B (reprint author), Observ Cote Azur, BP 4229, F-06304 Nice 4, France. EM gladman@obs-nice.fr NR 36 TC 72 Z9 72 U1 0 U2 2 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 12 PY 2001 VL 412 IS 6843 BP 163 EP 166 DI 10.1038/35084032 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 451AJ UT WOS:000169778700045 PM 11449267 ER PT J AU Allen, SW Taylor, GB Nulsen, PEJ Johnstone, RM David, LP Ettori, S Fabian, AC Forman, W Jones, C McNamara, B AF Allen, SW Taylor, GB Nulsen, PEJ Johnstone, RM David, LP Ettori, S Fabian, AC Forman, W Jones, C McNamara, B TI Chandra X-ray observations of the 3C 295 cluster core SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; galaxies : clusters; individual : 3C 295; cooling flows; intergalactic medium; radio continuum : galaxies; X-rays : galaxies : clusters ID ACTIVE GALACTIC NUCLEI; COOLING FLOW GALAXIES; OPTICAL-SPECTRA; STAR-FORMATION; LUMINOUS CLUSTERS; PERSEUS CLUSTER; RADIO GALAXIES; EMITTING GAS; COLD CLOUDS; DUST AB We examine the properties of the X-ray gas in the central regions of the distant (z = 0.46), X-ray luminous cluster of galaxies surrounding the powerful radio source 3C 295, using observations made with the Chandra Observatory. Between radii of 50 and 500 kpc, the cluster gas is approximately isothermal with an emission-weighted temperature, kT similar to5 keV. Within the central 50-kpc radius this value drops to kT similar to3.7 keV. The spectral and imaging Chandra data indicate the presence of a cooling flow within the central 50-kpc radius of the cluster, with a mass deposition rate of approximately 280 M. yr(-1). We estimate an age for the cooling flow of 1-2 Gyr, which is approximately 1000 times older than the central radio source. We find no evidence in the X-ray spectra or images for significant heating of the X-ray gas by the radio source. We report the detection of an edge-like absorption feature in the spectrum for the central 50-kpc region, which may be caused by oxygen-enriched dust grains. The implied mass in metals seen in absorption could have been accumulated by the cooling flow over its lifetime. Combining the results on the X-ray gas density profile with radio measurements of the Faraday rotation measure in 3C 295, we estimate the magnetic field strength in the region of the cluster core to be B similar to 12 muG. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Wollongong, Dept Engn Phys, Wollongong, NSW 2522, Australia. RP Allen, SW (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. RI Ettori, Stefano/N-5004-2015 OI Ettori, Stefano/0000-0003-4117-8617 NR 72 TC 77 Z9 77 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 11 PY 2001 VL 324 IS 4 BP 842 EP 858 DI 10.1046/j.1365-8711.2001.04315.x PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 455NR UT WOS:000170033400007 ER PT J AU Marengo, M Ivezic, Z Knapp, GR AF Marengo, M Ivezic, Z Knapp, GR TI 100-yr mass-loss modulations on the asymptotic giant branch SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars : AGB and post-AGB; circumstellar matter; stars : mass-loss; stars : variables : other; infrared : stars ID CIRCUMSTELLAR DUST SHELLS; LATE-TYPE STARS; SEMIREGULAR VARIABLES; TYPES SRA; RADIATIVE-TRANSFER; EMISSION FEATURES; EVOLVED STARS; INFRARED OBSERVATIONS; SUPER-GIANTS; AGB STARS AB We analyse the differences in infrared circumstellar dust emission between oxygen-rich Mira and non-Mira stars, and find that they are statistically significant. In particular, we find that these stars segregate in the K-[12] versus [12]-[25] colour-colour diagram, and have distinct properties of the IRAS LRS spectra, including the peak position of the silicate emission feature. We show that the infrared emission from the majority of non-Mira stars cannot be explained within the context of standard steady-state outflow models. The models can be altered to fit the data for non-Mira stars by postulating non-standard optical properties for silicate grains, or by assuming that the dust temperature at the inner envelope radius is significantly lower (300-400 K) than typical silicate grain condensation temperatures (800-1000 K). We argue that the latter is more probable and provide detailed model fits to the IRAS LRS spectra for 342 stars. These fits imply that two-thirds of non-Mira stars and one-third of Mira stars do not have hot dust (> 500 K) in their envelopes. The absence of hot dust can be interpreted as a recent (similar to 100 yr) decrease in the mass-loss rate. The distribution of best-fitting model parameters agrees with this interpretation and strongly suggests that the mass loss resumes on similar time-scales. Such a possibility appears to be supported by a number of spatially resolved observations (e.g. recent Hubble Space Telescope images of the multiple shells in the Egg Nebula) and is consistent with new dynamical models for mass loss on the asymptotic giant branch. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Scuola Int Super Studi Avanzati, SISSA, Trieste, Italy. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. RP Marengo, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM mmarengo@cfa.harvard.edu; ivezic@astro.princeton.edu; gk@astro.princeton.edu NR 53 TC 14 Z9 14 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 11 PY 2001 VL 324 IS 4 BP 1117 EP 1130 DI 10.1046/j.1365-8711.2001.04399.x PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 455NR UT WOS:000170033400032 ER PT J AU Rines, K Mahdavi, A Geller, MJ Diaferio, A Mohr, JJ Wegner, G AF Rines, K Mahdavi, A Geller, MJ Diaferio, A Mohr, JJ Wegner, G TI X-ray-emitting groups in the infall region of Abell 2199 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : clusters : general; galaxies : kinematics and dynamics ID ALL-SKY SURVEY; GALAXY CLUSTERS; SHAPLEY SUPERCLUSTER; RICH CLUSTERS; MASS; SUBSTRUCTURE; FILAMENTS; DYNAMICS; CATALOG; ROSAT AB Using a large redshift survey covering 95 deg(2), we demonstrate that the infall region of Abell 2199 contains Abell 2197, one or two X-ray-emitting groups, and up to five additional groups identified in redshift surveys. Our survey shows that the X-ray-emitting systems, located at projected radii of 1.degrees4, 1.degrees9, and 5.degrees1 (2.2, 3.1, and 8.0 h(-1) Mpc), are connected kinematically to A2199. A2197 is itself an optically rich cluster; its weak X-ray emission suggests that it is much less massive than A2199. The absence of a sharp peak in the infall pattern at the position of A2197 supports this hypothesis. The outermost group is well outside the virial region of A2199, and it distorts the infall pattern in redshift space. The two X-ray-emitting groups are roughly colinear, suggesting the existence of an extended (8.0 h(-1) Mpc) filament. The identification of these infalling groups provides direct support of hierarchical structure formation; studies of these systems will provide insights into structure evolution. Groups in the infall regions of nearby clusters may offer a unique probe of the physics of the warm/hot ionized medium (WHIM), which is difficult to observe directly with current instruments. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Turin, Dipartimento Fis Gen Amedeo Avogadro, Turin, Italy. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. RP Rines, K (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 35 TC 22 Z9 24 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 JUL 10 PY 2001 VL 555 IS 2 BP 558 EP 562 DI 10.1086/321513 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453YR UT WOS:000169946200002 ER PT J AU Barth, AJ Sarzi, M Rix, HW Ho, LC Filippenko, AV Sargent, WLW AF Barth, AJ Sarzi, M Rix, HW Ho, LC Filippenko, AV Sargent, WLW TI Evidence for a supermassive black hole in the S0 galaxy NGC 3245 SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; galaxies : elliptical and lenticular, cD; galaxies : individual (NGC 3245); galaxies : kinematics and dynamics; galaxies : nuclei ID SPACE-TELESCOPE OBSERVATIONS; DWARF SEYFERT NUCLEI; VELOCITY DISPERSION; ELLIPTIC GALAXIES; ACCRETION DISK; GALACTIC NUCLEI; HOST GALAXIES; DARK-MATTER; IONIZED-GAS; DUST AB The S0 galaxy NGC 3245 contains a circumnuclear disk of ionized gas and dust with a radius of 1."1 (110 pc), making it an ideal target for dynamical studies with the Hubble Space Telescope (HST). We have obtained spectra of the nuclear disk with the Space Telescope Imaging Spectrograph, using a 0."2 wide slit at five parallel positions. Measurements of the H alpha and [N II] emission lines are used to map out the kinematic structure of the disk in unprecedented detail. The data reveal a rotational velocity field with a steep velocity gradient across the innermost 0."4. We construct dynamical models for a thin gas disk in circular rotation, using HST optical images to map out the gravitational potential due to stars. Our modeling code includes the blurring due to the telescope point-spread function and the nonzero slit width, as well as the instrumental shift in measured wavelength for light entering the slit off-center, so as to simulate the data as closely as possible. The H alpha + [N II] surface brightness measured from an HST narrowband image is folded into the models, and we demonstrate that many of the apparent small-scale irregularities in the observed velocity curves are the result of the patchy distribution of emission-line surface brightness. Over most of the disk, the models are able to fit the observed radial velocity curves closely, although there are localized regions within the disk that appear to be kinematically disturbed relative to the overall rotational pattern. The velocity dispersion of [N II] lambda 6584 rises from sigma approximate to 50 km s(-1) in the outer disk to similar to 160 km s(-1) at the nucleus, and most of this line width cannot be attributed to rotational or instrumental broadening. To account for the possible dynamical effect of the intrinsic velocity dispersion in the gas, we also calculate models that include a correction for asymmetric drift. This correction increases the derived black hole mass by 12% but leads to slightly poorer fits to the data. A central dark mass of (2.1 +/-0.5) x 10(8) M-circle dot is required for the models to reproduce the steep central velocity gradient. This value for the central mass is consistent with recently discovered correlations between black hole mass and bulge velocity dispersion. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Padua, Dipartimento Astron, I-35122 Padua, Italy. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Caltech 10524, Palomar Observ, Pasadena, CA 91125 USA. RP Barth, AJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 57 TC 101 Z9 102 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 JUL 10 PY 2001 VL 555 IS 2 BP 685 EP 708 DI 10.1086/321523 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453YR UT WOS:000169946200014 ER PT J AU Psaltis, D AF Psaltis, D TI Compton scattering in static and moving media. II. System-frame solutions for spherically symmetric flows SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; plasmas; radiation mechanisms : thermal; radiative transfer ID CONVERGING FLUID-FLOW; X-RAY-SPECTRA; APPROXIMATE RADIATIVE-TRANSFER; ACTIVE GALACTIC NUCLEI; NEUTRON-STARS; TRANSFER EQUATION; DOMINATED SHOCK; ACCRETION; PLASMA; MODEL AB I study the formation of Comptonization spectra in spherically symmetric, fast-moving media in a flat spacetime. I analyze the mathematical character of the moments of the transfer equation in the system frame and describe a numerical method that provides fast solutions of the time-independent radiative transfer problem that are accurate in both the diffusion and free-streaming regimes. I show that even if the flows are mildly relativistic (V similar to 0.1, where V is the electron bulk velocity in units of the speed of light), terms that are second order in V alter the emerging spectrum both quantitatively and qualitatively. In particular, terms that are second order in V produce power-law spectral tails, which are the dominant feature at high energies, and therefore cannot be neglected. I further show that photons from a static source are upscattered by the bulk motion of the medium even if the velocity field does not converge. Finally, I discuss these results in the context of radial accretion onto and outflows from compact objects. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Psaltis, D (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 47 TC 18 Z9 18 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 JUL 10 PY 2001 VL 555 IS 2 BP 786 EP 800 DI 10.1086/323329 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453YR UT WOS:000169946200020 ER PT J AU Murray, N Chaboyer, B Arras, P Hansen, B Noyes, RW AF Murray, N Chaboyer, B Arras, P Hansen, B Noyes, RW TI Stellar pollution in the solar neighborhood SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; planetary systems; stars : abundances; stars : chemically peculiar ID PICTORIS CIRCUMSTELLAR DISK; T-TAURI STARS; BETA-PICTORIS; LITHIUM ABUNDANCES; PLANETARY SYSTEM; CHEMICAL EVOLUTION; GALACTIC DISK; ASTEROID BELT; MAIN-SEQUENCE; ACCRETION AB We study spectroscopically determined iron abundances of 640 solar-type stars to search for the signature of accreted iron-rich material. We find that the metallicity [Fe/H] of a subset of 466 main-sequence stars, when plotted as a function of stellar mass, mimics the pattern seen in lithium abundances in open clusters. Using Monte Carlo models, we find that, on average, these stars appear to have accreted similar to0.5 M-circle plus of iron while on the main-sequence. A consistency check is provided by a much smaller sample of 19 stars in the Hertzsprung gap, which are slightly evolved and the convection zones of which are significantly more massive; they have lower average [Fe/H], and their metallicity shows no clear variation with stellar mass. We argue that our Sun is likely to have accreted a similar amount of iron; in this respect, most systems resemble ours rather than the currently known extrasolar planetary systems. These findings suggest that terrestrial-type material is common around solar-type stars. C1 Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Dartmouth Coll, Dept Phys & Astron, Wilder Lab 6127, Hanover, NH 03755 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Toronto, Canadian Inst Theoret Astrophys, 60 St George St, Toronto, ON M5S 3H8, Canada. EM murray@cita.utoronto.ca; chaboyer@heather.dartmouth.edu; arras@cita.utoronto.ca; hansen@astro.princeton.edu; noyes@cfa.harvard.edu OI Chaboyer, Brian/0000-0003-3096-4161 NR 81 TC 67 Z9 67 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 JUL 10 PY 2001 VL 555 IS 2 BP 801 EP 815 DI 10.1086/321527 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453YR UT WOS:000169946200021 ER PT J AU Medvedev, MV Rybicki, G AF Medvedev, MV Rybicki, G TI The structure of self-gravitating polytropic systems with n around 5 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : star clusters; ISM : clouds; methods : analytical; stars : formation; stars : interiors AB We investigate the structure of self-gravitating polytropic stellar systems. We present a method that allows us to obtain approximate analytical solutions, psi (n+epsilon)(x) of the nonlinear Poisson equation with the polytropic index n+epsilon, given the solution psi (n)(x) with the polytropic index n, for any positive or negative epsilon, such that \epsilon\ <<1. A similar technique has been developed independently by Seidov & Kuzakhmedov. Application of this method to the spherically symmetric stellar polytropes with n similar or equal to 5 yields the solutions that describe spatially bound systems, if n <5, and the formation of a second core, if n>5. A heuristic approximate expression for the radial profile is also presented. Because of the duality between stellar and gas polytropes, our results are valid for gaseous, self-gravitating, polytropic systems (e.g., molecular clouds) with index gamma similar or equal to 6/5. The stability of such systems and observational consequences for both stellar and gaseous systems are discussed. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. IV Kurchatov Atom Energy Inst, RRC, Inst Nucl Fus, Moscow 123182, Russia. RP Medvedev, MV (reprint author), Univ Toronto, Canadian Inst Theoret Astrophys, 60 St George St, Toronto, ON M5S 3H8, Canada. NR 6 TC 8 Z9 8 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 JUL 10 PY 2001 VL 555 IS 2 BP 863 EP 867 DI 10.1086/321508 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453YR UT WOS:000169946200029 ER PT J AU Vikhlinin, A Markevitch, M Forman, W Jones, C AF Vikhlinin, A Markevitch, M Forman, W Jones, C TI Zooming in on the coma cluster with Chandra: Compressed warm gas in the brightest cluster galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : clusters : individual (Coma); galaxies : individual (NGC 4874, NGC 4889); magnetic fields; X-rays : galaxies ID SPHERICAL CLOUDS; COOLING FLOWS; HOT GAS; SUPRATHERMAL EVAPORATION; MASS-LOSS; CONDUCTION AB The Chandra image of the central region of the Coma Cluster reveals that both its dominant galaxies, NGC 4874 and NGC 4889, retain the central parts of their X-ray gas coronae. The interstellar gas with a temperature of 1-2 keV is confined by the hot intergalactic medium of the Coma Cluster into compact clouds (only 3 kpc in radius) containing 10(8) M. of gas. The physical state of the gas in these clouds appears to be determined by a delicate balance between radiative cooling and suppressed (by a factor of 30-100) heat conduction through the interface between these clouds and the hot cluster gas. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Space Res Inst, Moscow, Russia. RP Vikhlinin, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Forman, William/0000-0002-9478-1682 NR 20 TC 67 Z9 67 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 JUL 10 PY 2001 VL 555 IS 2 BP L87 EP L90 DI 10.1086/323181 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 456XV UT WOS:000170108800003 ER PT J AU Young, PR Dupree, AK Wood, BE Redfield, S Linsky, JL Ake, TB Moos, HW AF Young, PR Dupree, AK Wood, BE Redfield, S Linsky, JL Ake, TB Moos, HW TI Far Ultraviolet Spectroscopic Explorer observations of Capella SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : chromospheres; stars : coronae; stars : individual (alpha Aurigae); stars : late-type; ultraviolet : stars ID STARS; LINE; ABUNDANCES; SPECTRUM; ORBIT AB Far Ultraviolet Spectroscopic Explorer observations of the binary system Capella reveal a rich emission-line spectrum containing neutral and ionic species, among them H I, O I, C III, O VI, S VI, Ne V, and Ne VI. In addition, Fe XVIII lambda 974.85, formed at temperatures of approximate to6 x 10(6) K, is detected. Whereas the strong transition region lines principally come from the G1 giant, consistent with results from previous ultraviolet observations, Fe XVIII is formed largely in the G8 giant atmosphere. Line ratios from C III suggest densities of (2-8) x 10(10) cm(-3), although anomalous line profiles of the 1176 Angstrom transition may signal optical depth effects. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Comp Sci Corp, Lanham, MD 20706 USA. RP Young, PR (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Redfield, Seth/0000-0003-3786-3486 NR 27 TC 38 Z9 38 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 2001 VL 555 IS 2 BP L121 EP L124 DI 10.1086/322863 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 456XV UT WOS:000170108800011 ER PT J AU Davies, REG AF Davies, REG TI Drop the 'concrete solution,' think things through SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Editorial Material RP Davies, REG (reprint author), Smithsonian Inst, Natl Air & Space Museum, Aeronaut Div, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 USA SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD JUL 9 PY 2001 VL 155 IS 2 BP 74 EP 74 PG 1 WC Engineering, Aerospace SC Engineering GA 451FQ UT WOS:000169790800044 ER PT J AU McCarthy, MC Apponi, AJ Gottlieb, CA Thaddeus, P AF McCarthy, MC Apponi, AJ Gottlieb, CA Thaddeus, P TI Rotational spectra of SiCN, SiNC, and the SiCnH (n=2, 4-6) radicals SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSFORM INFRARED OBSERVATION; LINEAR SILICON CARBIDES; LABORATORY DETECTION; ASTRONOMICAL DETECTION; ISOTOPIC-SUBSTITUTION; RHOMBOIDAL SIC3; EXCITED-STATE; CARBON CHAINS; 10 K; SPECTROSCOPY AB Three new silicon-carbon chains, SiC4H, SiC5H, and SiC6H, have been detected in a supersonic molecular beam by Fourier transform microwave spectroscopy. A detailed spectroscopic characterization of these and the previously described chains SiCCH, SiCN, and SiNC is given here. All six radicals are linear chains with (2)Pi electronic ground states and all have resolvable hyperfine structure in their lower rotational transitions; all except SiC5H have resolved lambda-type doubling. Because transitions of SiCCH, SiCN, and SiNC were also detected by millimeter-wave absorption spectroscopy in both spin components, for these the rotational, centrifugal distortion, and fine structure and hyperfine coupling constants were determined to high precision using the standard Hamiltonian for a molecule in a (2)Pi state. For SiC4H, SiC5H, and SiC6H, at least seven transitions in the lowest-energy fine structure component were measured between 7 and 30 GHz, and, at most, five spectroscopic constants were required to reproduce their spectra to a few parts in 10(7). The hyperfine coupling constants of the SiCnH radicals are fairly close to those of isovalent Cn+1H, indicating that the chemical bonding may be similar. The missing radical in the present sequence, SiC3H, may soon be found along with cyclic isomers of SiCCH and SiC4H. If SiC5H possesses strong electronic transitions in the visible like isovalent C6H, its spectrum should be detectable by long path optical spectroscopy. (C) 2001 American Institute of Physics. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP McCarthy, MC (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI McCarthy, Michael/0000-0001-9142-0008 NR 42 TC 29 Z9 29 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 8 PY 2001 VL 115 IS 2 BP 870 EP 877 DI 10.1063/1.1370068 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 448ZW UT WOS:000169660700036 ER PT J AU Reasenberg, RD Phillips, JD AF Reasenberg, RD Phillips, JD TI Testing the equivalence principle on a trampoline SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article; Proceedings Paper CT International Symposium on Testing the Equivalence Principle in Space CY SEP 04-07, 2000 CL GLASGOW, SCOTLAND SP Univ Stanford, Univ Strathclyde AB We are developing a Galilean test of the equivalence principle in which two pairs of test mass assemblies (TMA) are in free fall in a comoving vacuum chamber for about 0.9 s. The TMA are tossed upward, and the process repeats at 1.2 s intervals. Each TMA carries a solid quartz retroreflector and a payload mass of about one-third of the total TMA mass. The relative vertical motion of the TMA of each pair is monitored by a laser gauge working in an optical cavity formed by the retroreflectors. Single-toss precision of the relative acceleration of a single pair of TMA is 3.5 x 10(-12) g. The project goal of Deltag/g = 10(-13) can be reached in a single night's run, but repetition with altered configurations will be required to ensure the correction of systematic error to the nominal accuracy level. Because the measurements can be made quickly, we plan to study several pairs of materials. C1 Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Reasenberg, RD (reprint author), Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. NR 11 TC 6 Z9 6 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD JUL 7 PY 2001 VL 18 IS 13 BP 2435 EP 2445 DI 10.1088/0264-9381/18/13/306 PG 11 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 455ZL UT WOS:000170057600007 ER PT J AU Adams, RM AF Adams, RM TI Iraq's cultural heritage: Collateral damage SO SCIENCE LA English DT Editorial Material C1 Univ Calif San Diego, San Diego, CA 92103 USA. Smithsonian Inst, Washington, DC 20560 USA. RP Adams, RM (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 6 PY 2001 VL 293 IS 5527 BP 13 EP 13 DI 10.1126/science.293.5527.13 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 451BB UT WOS:000169780300001 PM 11441151 ER PT J AU Digel, SW Grenier, IA Hunter, SD Dame, TM Thaddeus, P AF Digel, SW Grenier, IA Hunter, SD Dame, TM Thaddeus, P TI Egret observations of Monoceros: Diffuse gamma-ray emission in the outer Galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : observations; ISM : molecules; radio lines : ISM ID MOLECULAR CLOUDS; MILKY-WAY; CO SURVEY; EXPERIMENT TELESCOPE; GALACTIC PLANE; SOLAR CIRCLE; COSMIC-RAY; HYDROGEN; CALIBRATION; ORION AB We present an analysis of the diffuse gamma-ray emission observed toward Monoceros by the Energetic Gamma-Ray Experiment Telescope (EGRET). The region studied, l = 210 degrees -250 degrees, b = -15 degrees to +20 degrees, has kinematically well-defined segments of the local and Perseus arms and is one of the best regions for the study of variations of cosmic-ray density across the outer Galaxy. The local gamma-ray emissivity is (1.81 +/- 0.17) x 10(-26) s(-1) sr(-1) for energies greater than 100 MeV. For energies greater than 300 MeV, the gamma-ray emissivity in Monoceros is consistent with that of other local clouds studied with EGRET, which suggests that the density of GeV cosmic-ray protons does not vary significantly on scales of less than 1 kpc. As with other local clouds studied with EGRET, an excess of emissivity is observed above 1 GeV relative to that predicted from the cosmic-ray spectrum at the Earth. The gamma-ray emissivity is apparently enhanced in the Perseus arm relative to the interarm regions, although to a much lesser degree than predicted by the model of Hunter et al. The molecular mass calibrating ratio, X = N(H(2))/W/(CO), is (1.64 +/- 0.31) x 10(20) cm(-2) (K km s(-1))(-1) in the local clouds and is apparently about the same (to within 50%) in Maddalena's cloud. An uncataloged, marginally significant (similar to4.5 sigma) unidentified point source near (215.degrees5, 0.degrees5) with a flux of (1.4 +/-0.5) x 10(-7) cm(-2) s(-1) (>100 MeV) is suggested by the data. C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. Univ Paris 07, F-75221 Paris 05, France. CE Saclay, Serv Astrophys, Gif Sur Yvette, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Digel, SW (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 661, Greenbelt, MD 20771 USA. RI Hunter, Stanley/D-2942-2012 NR 35 TC 22 Z9 22 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 3 PY 2001 VL 555 IS 1 BP 12 EP 22 DI 10.1086/321446 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500003 ER PT J AU White, M AF White, M TI Constraints from the damping tail SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; large-scale structure of universe ID MICROWAVE BACKGROUND-RADIATION; SCALE ANISOTROPY; FLAT UNIVERSE; DARK MATTER; RECOMBINATION AB The detection of anisotropy in the cosmic microwave background (CMB) on arcminute scales by the Cosmic Background Imager (CBI) provides us with our first measurement of the damping tail and closes one chapter in the CMB story. We now have experimental verification for all of the features in the temperature anisotropy spectrum predicted theoretically two decades ago. The CBI result allows us to constrain both parameterized models based on the inflationary cold dark matter paradigm and to examine model-independent constraints on the matter content, the distance to last scattering, and the thickness of the last scattering surface. In particular, we show that recombination had to proceed "slowly," with the surface of last scattering having a width Deltaz greater than or similar to 50. This provides strong constraints on nonstandard recombination scenarios. By providing a lower limit on the duration of recombination, it implies a lower limit on the polarization of the subdegree scale anisotropy, which is close to current experimental upper limits. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP White, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI White, Martin/I-3880-2015 OI White, Martin/0000-0001-9912-5070 NR 38 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 JUL 3 PY 2001 VL 555 IS 1 BP 88 EP 91 DI 10.1086/321433 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500011 ER PT J AU Finoguenov, A Arnaud, M David, LP AF Finoguenov, A Arnaud, M David, LP TI Temperature and heavy-element abundance profiles of cool clusters of galaxies from ASCA SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : abundances; galaxies : clusters : general; galaxies : evolution; intergalactic medium; supernovae : general; X-rays : galaxies ID X-RAY-CLUSTERS; CENTAURUS-CLUSTER; INTRACLUSTER MEDIUM; PSPC OBSERVATIONS; NEARBY CLUSTERS; RICH CLUSTERS; ROSAT; GAS; IRON; IA AB We perform a spatially resolved X-ray spectroscopic study of a set of 18 relaxed clusters of galaxies with gas temperatures below 4 keV. Spectral analysis was done using ASCA/SIS data coupled with the spatial information contained in ROSAT/PSPC and Einstein/IPC observations. We derive the temperature profiles using single-temperature fits and also correct for the presence of cold gas at the cluster centers. For all of the clusters in the sample, we derive Si and Fe abundance profiles. For a few of the clusters, we also derive Ne and S abundance profiles. We present a comparison of the elemental abundances derived at similar overdensities as well as element mass-to-light ratios. We conclude that the preferential accretion of low-entropy, low-abundance gas into the potentials of groups and cold clusters can explain most of the observed trends in metallicity. In addition, we discuss the importance of energy input from Type II supernovae on cluster scaling relations and on the relation between the observed scatter in the retainment of Type Ia supernova products with differences between the epoch of cluster formation. C1 Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Finoguenov, A (reprint author), Max Planck Inst Extraterr Phys, Giessenbachstr, D-85748 Garching, Germany. NR 68 TC 105 Z9 106 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 JUL 3 PY 2001 VL 555 IS 1 BP 191 EP 204 DI 10.1086/321457 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500020 ER PT J AU Mazzotta, P Markevitch, M Vikhlinin, A Forman, WR David, LP VanSpeybroeck, L AF Mazzotta, P Markevitch, M Vikhlinin, A Forman, WR David, LP VanSpeybroeck, L TI Chandra observation of RX J1720.1+2638: A nearly relaxed cluster with a fast-moving core? SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : clusters : individual (RX J1720.1+2638); galaxies : fundamental parameters; intergalactic medium; X-rays : galaxies ID X-RAY; GALACTIC HALOS; DARK-MATTER; GALAXIES; ROSAT; MASS; SUBSTRUCTURE; EVOLUTION; SURVIVAL; VIRGO AB We have analyzed the Chandra observation of the distant (z = 0.164) galaxy cluster RX J1720.1+2638, in which we find sharp features in the X-ray surface brightness on opposite sides of the X-ray peak: an edge at about 250h(50)(-1) kpc to the southeast and a plateau at about 130h(50)(-1) kpc to the northwest. The surface brightness edge and the plateau can be modeled as a gas density discontinuity (jump) and a slope change (break). The temperature profiles suggest that the jump and the break are the boundaries of a central, group-size (d approximate to 380h(50)(-1) kpc), dense, cold (T approximate to 4 keV) gas cloud, embedded in a diffuse hot (T approximate to 10 keV) intracluster medium. The density jump and the temperature change across the discontinuity are similar to the "cold fronts" discovered by Chandra in A2142 and A3667 and suggest subsonic motion of this central gas cloud with respect to the cluster itself. The most natural explanation is that we are observing a merger in the very last stage before the cluster becomes fully relaxed. However, the data are also consistent with an alternative scenario in which RX J1720.1+2638 is the result of the collapse of two co-located density perturbations, the first a group-scale perturbation collapse followed by a second cluster-scale perturbation collapse that surrounded, but did not destroy, the first one. We also show that, because of the core motion, the total mass inside the cluster core, derived under the assumption of hydrostatic equilibrium, may underestimate the true cluster mass. If widespread, such motion may partially explain the discrepancy between X-ray and the strong-lensing mass determinations found in some clusters. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Russian Acad Sci, Inst Space Res, Moscow 117901, Russia. RP Mazzotta, P (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Mazzotta, Pasquale/B-1225-2016 OI Mazzotta, Pasquale/0000-0002-5411-1748 NR 30 TC 97 Z9 97 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 JUL 3 PY 2001 VL 555 IS 1 BP 205 EP 214 DI 10.1086/321484 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500021 ER PT J AU Marcy, GW Butler, RP Vogt, SS Liu, MC Laughlin, G Apps, K Graham, JR Lloyd, J Luhman, KL Jayawardhana, R AF Marcy, GW Butler, RP Vogt, SS Liu, MC Laughlin, G Apps, K Graham, JR Lloyd, J Luhman, KL Jayawardhana, R TI Two substellar companions orbiting HD 168443 SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary systems; stars : individual (HD 168443) ID PLANETARY SYSTEMS; PROTOSTELLAR DISKS; ADAPTIVE OPTICS; GIANT PLANETS; SEARCH; STARS; PROTOPLANETS; PRECISION; MIGRATION; DIVERSITY AB Precise Doppler measurements during 4.4 yr from the Keck/HIRES spectrometer reveal two superimposed Keplerian velocity variations for HD 168443 (G6 IV). A simultaneous orbital Dt to both companions yields companion masses of M sin i = 7.7 and 17.2 M-JUP, orbital periods of P = 58 days and 4.8 yr, semimajor axes of a = 0.29 and 2.9 AU, and eccentricities of e = 0.53 and 0.20. An upper limit to the mass of the outer companion of 42 M-JUP is derived from the lack of astrometric wobble. The outer companion was not detected with Keck adaptive optics in the near-IR. Dynamical simulations show that the system is remarkably stable for all possible masses of both companions. The two orbiting companions have masses that are probably near and slightly above the upper end of the observed mass distribution of "planets" at 10 M-JUP. Formation in a protoplanetary disk seems plausible. But these objects present a puzzle about their formation and dynamical history, as well as about their possible kinship with planetary systems and triple-star systems. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Sussex, Brighton BN1 9QJ, E Sussex, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Marcy, GW (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Butler, Robert/B-1125-2009; Lloyd, James/B-3769-2011 NR 32 TC 80 Z9 81 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 JUL 3 PY 2001 VL 555 IS 1 BP 418 EP 425 DI 10.1086/321445 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500038 ER PT J AU McClintock, JE Haswell, CA Garcia, MR Drake, JJ Hynes, RI Marshall, HL Muno, MP Chaty, S Garnavich, PM Groot, PJ Lewin, WHG Mauche, CW Miller, JM Pooley, GG Shrader, CR Vrtilek, SD AF McClintock, JE Haswell, CA Garcia, MR Drake, JJ Hynes, RI Marshall, HL Muno, MP Chaty, S Garnavich, PM Groot, PJ Lewin, WHG Mauche, CW Miller, JM Pooley, GG Shrader, CR Vrtilek, SD TI Complete and simultaneous spectral observations of the black hole X-ray nova XTE J1118+480 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : individual (XTE J1118+480); ultraviolet : stars; X-rays : stars ID INTERSTELLAR-MEDIUM; H-I; ULTRAVIOLET; TRANSIENT; STATE; MASS AB The X-ray nova XTE J1118+480 suffers minimal extinction (b = 62 degrees) and therefore represents an outstanding opportunity for multiwavelength studies. Hynes et al. conducted the first such study, which was centered on 2000 April 8 using UKIRT, EUVE, HST, and RXTE. On 2000 April 18, the Chandra X-Ray Observatory obtained data coincident with a second set of observations using all of these same observatories. A 30 ks grating observation using Chandra yielded a spectrum with high resolution and sensitivity covering the range 0.24-7 keV. Our near-simultaneous observations cover approximate to 80% of the electromagnetic spectrum from the infrared to hard X-rays. The UV/X-ray spectrum of XTE J1118+480 consists of two principal components. The Drst of these is an approximate to 24 eV thermal component that is caused by an accretion disk with a large inner disk radius : greater than or similar to 35R(Schw). The second is a quasi power-law component that was recorded with complete spectral coverage from 0.4 to 160 keV. A model for this twocomponent spectrum is presented in a companion paper by Esin et al. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Cambridge, Cavendish Lab, Mullard Radio Astron Observ, Cambridge CB3 0HE, England. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP McClintock, JE (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Groot, Paul/K-4391-2016; OI Groot, Paul/0000-0002-4488-726X; Chaty, Sylvain/0000-0002-5769-8601 NR 34 TC 107 Z9 107 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 JUL 3 PY 2001 VL 555 IS 1 BP 477 EP 482 DI 10.1086/321449 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500046 ER PT J AU Esin, AA McClintock, JE Drake, JJ Garcia, MR Haswell, CA Hynes, RI Muno, MP AF Esin, AA McClintock, JE Drake, JJ Garcia, MR Haswell, CA Hynes, RI Muno, MP TI Modeling the low-state spectrum of the X-ray nova XTE J1118+480 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (XTE J1118+480); X-rays : stars ID ACTIVE GALACTIC NUCLEI; BLACK-HOLE; ACCRETION DISKS; BINARY-SYSTEMS; CYGNUS X-1; REFLECTION; TRANSIENT; DISCOVERY; CORONA; FLOWS AB Based on recent multiwavelength observations of the new X-ray nova XTE J1118+480, we can place strong constraints on the geometry of the accretion flow in which a low/hard-state spectrum, characteristic of an accreting black hole binary, is produced. We argue that the absence of any soft blackbody-like component in the X-ray band implies the existence of an extended hot optically thin region, with the optically thick cool disk truncated at some radius We show that such a model can indeed R-tr greater than or similar to 55R(Schw). reproduce the main features of the observed spectrum: the relatively high optical to X-ray ratio, the sharp downturn in the far-UV band, and the hard X-ray spectrum. The absence of the disk blackbody component also underscores the requirement that the seed photons for thermal Comptonization be produced locally in the hot flow, e.g., via synchrotron radiation. We attribute the observed spectral break at similar to2 keV to absorption in a warm, partially ionized gas. C1 CALTECH, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Open Univ, Dept Phys & Astron, Milton Keynes MK6 7AA, Bucks, England. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Esin, AA (reprint author), CALTECH, 130-33, Pasadena, CA 91125 USA. NR 49 TC 116 Z9 116 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 JUL 3 PY 2001 VL 555 IS 1 BP 483 EP 488 DI 10.1086/321450 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500047 ER PT J AU Orosz, JA Kuulkers, E van der Klis, M McClintock, JE Garcia, MR Callanan, PJ Bailyn, CD Jain, RK Remillard, RA AF Orosz, JA Kuulkers, E van der Klis, M McClintock, JE Garcia, MR Callanan, PJ Bailyn, CD Jain, RK Remillard, RA TI A black hole in the superluminal source SAX J1819.3-2525 (V4641 SGR) SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : spectroscopic; black hole physics; stars : individual (V4641 Sagittarii); X-rays : stars ID GRO J1655-40; RELATIVISTIC JETS; BINARY A0620-00; SPACED DATA; MASS; SPECTROSCOPY; QUIESCENCE; GALAXY AB Spectroscopic observations of the fast X-ray transient and superluminal jet source SAX J1819.3-2525 (V4641 Sgr) reveal a best-fitting period of P-spect = 2.81678 +/- 0.00056 days and a semiamplitude of K-2 = 211.0 +/- 3.1 km s(-1). The optical mass function is f(M) = 2.74 +/- 0.12 M-. We find a photometric period of P-photo = 2.81730 +/- 0.0001 days using a light curve measured from photographic plates. The folded light curve resembles an ellipsoidal light curve with two maxima of roughly equal height and two minima of unequal depth per orbital cycle. The secondary star is a late B-type star that has evolved off the main sequence. Using a moderate resolution spectrum (R = 7000) we measure T-eff = 10500 +/- 200 K, log g = 3.5 +/- 0.1, and V-rot sin i = 123 +/- 4 km s(-1) (1 sigma errors). Assuming synchronous rotation, our measured value of the projected rotational velocity implies a mass ratio of Q equivalent to M-1/M-2 = 1.50 +/- 0.008 (1 sigma). The lack of X-ray eclipses implies an upper limit to the inclination of i less than or equal to 70 degrees .7. On the other hand, the large amplitude of the folded light curve (approximate to0.5 mag) implies a large inclination (i greater than or similar to 60 degrees). Using the above mass function, mass ratio, and inclination range, the mass of the compact object is in the range 8.73 less than or equal to M1 less than or equal to 11.7 M.and the mass of the secondary star is in the range 5.49 less than or equal to M-2 less than or equal to 8.14 M. (90% confidence). The mass of the compact object is well above the maximum mass of a stable neutron star, and we conclude that V4641 Sgr contains a black hole. The B-star secondary is by far the most massive, the hottest, and the most luminous secondary of the dynamically confirmed black hole X-ray transients. We find that the alpha -process elements nitrogen, oxygen, calcium, magnesium, and titanium may be over-abundant in the secondary star by factors of 2-10 times with respect to the Sun. Finally, assuming E(B-V) = 0.32 +/- 0.10, we find a distance 7.4 less than or equal to d less than or equal to 12.31 kpc (90% confidence). This large distance and the high proper motions observed for the radio counterpart make V4641 Sgr possibly the most superluminal galactic source known, with an apparent expansion velocity of greater than or similar to9.2c and a bulk Lorentz factor of Gamma greater than or similar to 9.5, assuming that the jets were ejected during one of the bright X-ray flares observed with the Rossi X-ray Timing Explorer. C1 Univ Utrecht, Astron Inst, NL-3508 TA Utrecht, Netherlands. SRON, NL-3584 CA Utrecht, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Natl Inst Nucl & High Energy Phys, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Univ Ireland Univ Coll Cork, Dept Phys, Cork, Ireland. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Orosz, JA (reprint author), Univ Utrecht, Astron Inst, Postbus 80000, NL-3508 TA Utrecht, Netherlands. EM J.A.Orosz@astro.uu.nl; e.kuulkers@sron.nl; michiel@astro.uva.nl; jem@cfa.harvard.edu; garcia@head-cfa.harvard.edu; paulc@ucc.ie; bailyn@astro.yale.edu; rjain@astro.yale.edu; rr@space.mit.edu NR 50 TC 140 Z9 141 U1 0 U2 3 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 JUL 3 PY 2001 VL 555 IS 1 BP 489 EP 503 DI 10.1086/321442 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500048 ER PT J AU Sankrit, R Wood, K AF Sankrit, R Wood, K TI Resonance-line scattering in supernova remnant shocks SO ASTROPHYSICAL JOURNAL LA English DT Article DE radiative transfer; shock waves; supernova remnants; ultraviolet : ISM ID HOPKINS-ULTRAVIOLET-TELESCOPE; CYGNUS-LOOP; POLARIZATION; EMISSION; FILAMENT; WAVE AB We present a three-dimensional radiative transfer model to examine the effects of resonance-line scattering in the postshock flow behind a nonradiative supernova remnant shock. For a rippled shock front viewed edge-on, line scattering significantly reduces the observed flux of C IV lambda 1549 and N V lambda 1240, two important diagnostic lines in the ultraviolet spectra of supernova remnants. The correction factor (defined to be the ratio of the line flux that would be observed neglecting scattering to the actual observed line flux) is a function of position within the filament. For sufficiently large regions that include crisp edges as well as more diffuse regions of the filament structure, the C IV and N V correction factors are between about 1.5 and 3.5 (and the C IV correction factor is invariably larger than the N V correction factor). The correction factors have a larger range when smaller regions are considered. The C IV correction factor is about 6 at the filament edges, while the N V correction factor is about 4. These simulations of resonance-line scattering will be useful for the analysis of supernova remnant shock spectra. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Sankrit, R (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 17 TC 2 Z9 2 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 JUL 3 PY 2001 VL 555 IS 1 BP 532 EP 539 DI 10.1086/321432 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XY UT WOS:000169944500051 ER PT J AU Padoan, P Kim, S Goodman, A Staveley-Smith, L AF Padoan, P Kim, S Goodman, A Staveley-Smith, L TI A new method to measure and map the gas scale height of disk galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : ISM; galaxies : structure; Magellanic Clouds; turbulence ID LARGE-MAGELLANIC-CLOUD; ON SPIRAL GALAXIES; GALACTIC H-I; SURFACE PHOTOMETRY; NGC-891; LIGHT; SHELLS; COLOR AB We propose a new method to measure and map the gas scale height of nearby disk galaxies. This method is applied successfully to the Australia Telescope Compact Array interferometric H I survey of the Large Magellanic Cloud (LMC); it could also be applied to a significant number of nearby disk galaxies, thanks to the next generation of interferometric facilities, such as the expanded Very Large Array and the Combined Array for Research in Millimeter-wave Astronomy. The method consists of computing the spectral correlation function (SCF) for a spectral line map of a face-on galaxy. The SCF quantifies the correlation between spectra at different map positions as a function of their separation and is sensitive to the properties of both the gas mass distribution and the gas velocity field. It is likely that the spatial correlation properties of the gas density and velocity fields in a galactic disk are sensitive to the value of the scale height of the gas disk. A scale-free turbulent cascade is unlikely to extend to scales much larger than the disk scale height since the disk dynamics on those larger scales should be dominated by two-dimensional motions. We find a clear feature in the SCF of the LMC H I disk, on the scale of approximate to 180 pc, which we identify as the disk scale height. We are also tentatively able to map variations of the scale height over the disk. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CSIRO, Australia Telescope Natl Facil, Epping, NSW 1710, Australia. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM ppadoan@cfa.harvard.edu; skim@cfa.harvard.edu; agoodman@cfa.harvard.edu RI Staveley-Smith, Lister/A-1683-2011; Goodman, Alyssa/A-6007-2010; OI Staveley-Smith, Lister/0000-0002-8057-0294; Goodman, Alyssa/0000-0003-1312-0477; Padoan, Paolo/0000-0002-5055-5800 NR 30 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 JUL 3 PY 2001 VL 555 IS 1 BP L33 EP L36 DI 10.1086/321735 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453YL UT WOS:000169945700008 ER PT J AU Schwartz, GT Dean, C AF Schwartz, GT Dean, C TI Ontogeny of canine dimorphism in extant hominoids SO AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY LA English DT Review ID CHIMPANZEES PAN-TROGLODYTES; LOCALLY WEIGHTED REGRESSION; BODY-SIZE DIMORPHISM; SEXUAL-DIMORPHISM; DENTAL DEVELOPMENT; ANTHROPOID PRIMATES; AFRICAN APES; HISTOLOGICAL RECONSTRUCTION; INTRASEXUAL COMPETITION; TOOTH CALCIFICATION AB Many behavioral and ecological factors influence the degree of expression of canine dimorphism for different reasons. Regardless of its socioecological importance, we know virtually nothing about the processes responsible for the development of canine dimorphism. Our aim here is to describe the developmental process(es) regulating canine dimorphism in extant hominoids, using histological markers of tooth growth. Teeth preserve a permanent record of their ontogeny in the form of short- and long-period incremental markings in both enamel and dentine. We selected 52 histological sections of sexed hominoid canine teeth from a total sample of 115, from which we calculated the time and rate of cuspal enamel formation and the rate at which ameloblasts differentiate along the future enamel-dentine junction (EDJ) to the end of crown formation. Thus, we were able to reconstruct longitudinal growth curves for height attainment in male and female hominoid canines. Male hominoids consistently take longer to form canine crowns than do females (although not significantly so for our sample of Home). Male orangutans and gorillas occasionally take up to twice as long as females to complete enamel formation. The mean ranges of female canine crown formation times are similar in Pan, Gorilla, and Pongo. Interspecific differences between female Pan canine crown heights and those of Gorilla and Porzgo, which are taller, result from differences in rates of growth. Differences in canine crown heights between male Pan and the taller, more dimorphic male Gorilla and Pongo canines result both from differences in total time taken to form enamel and from faster rates of growth in Gorilla and Pongo. Although modern human canines do not emerge as significantly dimorphic in this study, it is well-known that sexual dimorphism in canine crown height exists. Larger samples of sexed modern human canines are therefore needed to identify clearly what underlies this. (C) 2001 Wiley-Liss, Inc. C1 George Washington Univ, Dept Anthropol, Washington, DC 20052 USA. Natl Museum Nat Hist, Human Origins Program, Smithsonian Inst, Washington, DC 20560 USA. UCL, Dept Anat & Dev Biol, Evolutionary Anat Unit, London WC1E 6JJ, England. RP Schwartz, GT (reprint author), George Washington Univ, Dept Anthropol, 2110 G St NW, Washington, DC 20052 USA. EM garys@gwu.edu NR 110 TC 45 Z9 45 U1 3 U2 13 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-9483 EI 1096-8644 J9 AM J PHYS ANTHROPOL JI Am. J. Phys. Anthropol. PD JUL PY 2001 VL 115 IS 3 BP 269 EP 283 DI 10.1002/ajpa.1081 PG 15 WC Anthropology; Evolutionary Biology SC Anthropology; Evolutionary Biology GA 451DE UT WOS:000169785200008 PM 11424078 ER PT J AU Sorensen, SS AF Sorensen, SS TI Presentation of the distinguished Public Service Medal for 2000 to Richard S. Fiske SO AMERICAN MINERALOGIST LA English DT Biographical-Item C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. RP Sorensen, SS (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, NHB-119, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD JUL-AUG PY 2001 VL 86 IS 7-8 BP 952 EP 952 PG 1 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 451PG UT WOS:000169810000024 ER PT J AU Fiske, RS AF Fiske, RS TI Acceptance of the distinguished Public Service Medal of 2000 SO AMERICAN MINERALOGIST LA English DT Article C1 Smithsonian Inst, Natl Museum Nat Hist, Washington, DC 20560 USA. RP Fiske, RS (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD JUL-AUG PY 2001 VL 86 IS 7-8 BP 953 EP 953 PG 1 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 451PG UT WOS:000169810000025 ER PT J AU Gingerich, O AF Gingerich, O TI The sun in the church: Cathedrals as solar observatories SO ANNALS OF SCIENCE LA English DT Book Review C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Gingerich, O (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0003-3790 J9 ANN SCI JI Ann. Sci. PD JUL PY 2001 VL 58 IS 3 BP 325 EP 326 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA 451HB UT WOS:000169794500007 ER PT J AU Kenyon, SJ Proga, D Keyes, CD AF Kenyon, SJ Proga, D Keyes, CD TI The continuing slow decline of AG Pegasi SO ASTRONOMICAL JOURNAL LA English DT Article DE novae, cataclysmic variables; stars : evolution; stars : individual (AG Pegasi) ID LTE PHOTOIONIZATION MODELS; SYMBIOTIC BINARY STARS; COOL COMPONENTS; COLLIDING WINDS; EMISSION-LINES; Z-ANDROMEDAE; FE-VII; HM-SGE; COLLISION; NOVAE AB We analyze optical and ultraviolet observations of the symbiotic binary AG Pegasi acquired during 1992-1997. The bolometric luminosity of the hot component declined by a factor of 2-3 from 1980-1985 to 1997. Since 1992, the effective temperature of the hot component may have declined by 10%-20%, but this decline is comparable to the measurement errors. Optical observations of H beta and He I emission show a clear illumination effect, where high-energy photons from the hot component ionize the outer atmosphere of the red giant. Simple illumination models generally account for the magnitude of the optical and ultraviolet emission-line fluxes. High-ionization emission lines-[Ne V], [Mg V], and [Fe VII]-suggest mechanical heating in the outer portions of the photoionized red giant wind. This emission probably originates in a low-density region similar to 30-300 AU from the central binary. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Kenyon, SJ (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. OI Kenyon, Scott/0000-0003-0214-609X NR 65 TC 13 Z9 13 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 2001 VL 122 IS 1 BP 349 EP 359 DI 10.1086/321107 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XK UT WOS:000169943300030 ER PT J AU Graves, GR AF Graves, GR TI Factors governing the distribution of Swainson's warbler along a hydrological gradient in Great Dismal Swamp SO AUK LA English DT Article ID HABITAT SELECTION; BOUNDARY DETERMINATION; CONIFEROUS FORESTS; FORAGING BEHAVIOR; LOGICAL SYNTHESIS; BIRDS; FIELD; ENVIRONMENT; HISTORY AB Due to extensive clearing of bottomland forest in the southeastern United States, Swainson's Warbler (Limnothlypis swainsonii) is restricted in many drainages to seasonally inundated buffer zones bordering rivers and swamps. This migratory species is especially vulnerable to flooding because of its ground foraging ecology, but little is known about patterns of habitat occupancy at wetland ecotones. I investigated the physiognomic and floristic correlates of habitat use along a subtle hydrological gradient in the Great Dismal Swamp, southeastern Virginia. Hydrology is the driving force influencing vegetation and the distribution of Swainson's Warbler in that habitat. Foraging and singing stations of territorial males were significantly drier and more floristically diverse than unoccupied habitat. There was scant evidence that the distribution and abundance of particular plant species, including giant cane (Arundinaria gigantea), influenced habitat selection. Instead, Swainson's Warbler seems to evaluate potential territories on the basis of multiscale physiognomic, hydrological, and edaphic characteristics. Territories were characterized by extensive understory thickets (median = 36,220 small woody stems and cane culms per hectare; range, 14,000-81,400/ha), frequent greenbriar tangles, deep shade at ground level, and an abundance of leaf litter overlying moist organic soils. Those sites occurred most frequently in relatively well-drained tracts of broad-leaf forest that had suffered extensive canopy damage and windthrow. Data suggest a preference for early successional forest in the current landscape or disturbance gaps in primeval forest. Because territories in otherwise optimal habitat are abandoned when flooding extends into the breeding season, it is recommended that the water table be maintained at subsurface levels from late March through September in natural areas managed primarily for this species. Direct and indirect environmental factors that influence the breeding biology of the warbler are summarized in an envirogram. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. RP Graves, GR (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. EM graves.gary@nmnh.si.edu NR 81 TC 25 Z9 25 U1 1 U2 5 PU AMER ORNITHOLOGISTS UNION PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0004-8038 EI 1938-4254 J9 AUK JI AUK PD JUL PY 2001 VL 118 IS 3 BP 650 EP 664 DI 10.1642/0004-8038(2001)118[0650:FGTDOS]2.0.CO;2 PG 15 WC Ornithology SC Zoology GA 474KE UT WOS:000171105000007 ER PT J AU Schnitzler, HU Kalko, EKV AF Schnitzler, HU Kalko, EKV TI Echolocation by insect-eating bats SO BIOSCIENCE LA English DT Article ID LASIONYCTERIS-NOCTIVAGANS BATS; RANGE FORAGING STRATEGIES; AERIAL INSECTIVOROUS BATS; ACOUSTIC FLOW PERCEPTION; HOARY LASIURUS-CINEREUS; PREY DETECTION; HUNTING BEHAVIOR; PIPISTRELLE BATS; DAUBENTONS BAT; CF-BATS C1 Univ Tubingen, Lehrstuhl Tierphysiol, D-72076 Tubingen, Germany. Univ Ulm, Abt Expt Okol, D-89069 Ulm, Germany. Smithsonian Trop Res Inst, Panama City, Panama. Natl Museum Nat Hist, Washington, DC 20560 USA. RP Schnitzler, HU (reprint author), Univ Tubingen, Lehrstuhl Tierphysiol, Morgenstelle 28, D-72076 Tubingen, Germany. NR 41 TC 420 Z9 447 U1 18 U2 198 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD JUL PY 2001 VL 51 IS 7 BP 557 EP 569 DI 10.1641/0006-3568(2001)051[0557:EBIEB]2.0.CO;2 PG 13 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 460TH UT WOS:000170324300008 ER PT J AU Bula-Meyer, G Norris, JN AF Bula-Meyer, G Norris, JN TI Notes on new records of red algae from the Colombian Caribbean SO BOTANICA MARINA LA English DT Article ID LAURENCIA CERAMIALES; RHODOPHYTA; GIGARTINALES AB Six genera and 13 species of red algae, characteristic of sand-plain habitats between 10 and 28 in depths, are reported for the first time for the Caribbean coast of Colombia. They are Amphiroa beauvoisii Lamouroux. Halymenia pseudofloresia Collins et Howe, Dudresnaya bermudensis Setchell, D. crassa Howe, Sebdenia flabellata (J. Agardh) Parkinson, Agardhiella subulata (C. Agardh) Kraft et Wynne, Sarcodiotheca dichotoma (Howe) Dawson, S. divaricata W. R. Taylor, Chrysymenia enteromorpha (Harvey) Farlow, Lomentaria corallicola Borgesen, Dictyurus occidentalis J. Agardh, Laurencia brongniartii J. Agardh, and Micropeuce mucronata (Harvey) Kylin ex E. C. Oliveira. Agardhiella subulata differs from Solieria filiformis (Kutzing) Gabrielson both in morphology and in habitat. Sarcodiotheca caribaea from the Caribbean Sea is considered to be conspecific with S. dichotoma from the Gulf of California (Mexico), and it is reported for the second time for the Atlantic Ocean. Sarcodiotheca divaricata is reported for the second time for the Atlantic Ocean and for the first time for the Caribbean Sea. Lomentaria rawitscheri Joly (1957) from Brazil is considered here to be conspecific with L. corallicola Borgesen (1939) from the Gulf of Iran. C1 Univ Magdalena, Dept Biol, Santa Maria, RS, Brazil. Smithsonian Inst, Museum Natl Hist Nat, Dept Bot, Washington, DC 20560 USA. RP Bula-Meyer, G (reprint author), Univ Magdalena, Dept Biol, AA 890, Santa Maria, RS, Brazil. NR 90 TC 6 Z9 6 U1 2 U2 4 PU WALTER DE GRUYTER & CO PI BERLIN PA GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY SN 0006-8055 J9 BOT MAR JI Bot. Marina PD JUL PY 2001 VL 44 IS 4 BP 351 EP 360 DI 10.1515/BOT.2001.045 PG 10 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA 462AE UT WOS:000170395400007 ER PT J AU Glynn, PW Mate, JL Baker, AC Calderon, MO AF Glynn, PW Mate, JL Baker, AC Calderon, MO TI Coral bleaching and mortality in panama and Ecuador during the 1997-1998 El Nino-Southern oscillation event: Spatial/temporal patterns and comparisons with the 1982-1983 event SO BULLETIN OF MARINE SCIENCE LA English DT Article ID GREAT-BARRIER-REEF; EASTERN PACIFIC; EQUATORIAL PACIFIC; GALAPAGOS-ISLANDS; CLIMATE-CHANGE; TEMPERATURE; SEA; DISTURBANCE; DIVERSITY; HISTORY AB Bleaching and mortality of zooxanthellate corals during the 1997-98 El Ni (n) over tildeo-Southem Oscillation (ENSO) event are documented for eastern equatorial Pacific localities in Panama (Gulf of Chiriqui and Gulf of Panama) and Ecuador (Galapagos Islands and mainland coast). Overall, the very strong 1997-98 and 1982-83 ENSOs were similar in magnitude and duration, but varied spatially, resulting in different patterns of elevated sea temperature stress and coral responses during the two disturbance events, Two bleaching episodes occurred in the Gulf of Chiriqui, each coincident with high (greater than or equal to 30 degreesC) in situ temperatures and warm water filaments visible in NOAA/NCEP SST fields. Coral mortality was significantly different among localities: Galapagos Islands (26.2%) > Gulf of Chiriqui (13.1%) > coastal Ecuador (7.0%) > Gulf of Panama (0%). Coral mortality was notably higher (52-97%) in the eastern equatorial Pacific in 1982-83 than in 1997-98. Coral mortality among most sites within localities was also significantly different. Highest coral mortalities occurred at offshore compared with nearshore sites in Panama, and at the Galapagos Islands compared with mainland Ecuador. Although species responses varied among localities, tissue death was especially high in Millepora spp., Pavona Up., Pocillopora spp., and Porites spp. Corals present in relatively deep (12-18 m), inter-reef habitats suffered lower rates of bleaching and mortality than similar and different species present in shallow (1-10 m) habitats. Bleached coral tissues in the Gulf of Chiriqui demonstrated a significant increase in zooxanthella density, but only a slight increase in chlorophyll a concentration over a 5 mo respite, from the end of the first bleaching event (October 1997) to the beginning of the second event (March 1998). The use of molecular DNA techniques to compare algal symbionts in bleached and healthy coral colonies revealed a strong correlation between bleaching severity and symbiont genotype, regardless of depth. In particular, one symbiont genotype (commonly found in the scleractinian genus Pocillopora in the Gulf of Chiriqui) was particularly resistant to bleaching, indicating that symbiont diversity can play an important role in explaining spatial and host systematic patterns of bleaching. Extreme reductions in abundance of some species populations in Panama have resulted in local extirpations. It is possible that Millepora boschmai, a Gulf of Chiriqui endemic hydrocoral, is now extinct. Remnant patches of Gardineroseris planulata that survived the 1982-83 ENSO in the Galapagos Islands have also disappeared following the 1997-98 event, causing local extinctions. Marked declines in external bioerosion and corallivore abundances in Panama before and after the 1997-98 ENSO should have less of an effect on surviving corals than in 1982-83 when such effects continued to degrade reefs long after the initial disturbance. Surviving corals in the Galapagos Islands are still subject to heavy grazing pressure by abundant echinoid populations. The response of eastern Pacific coral reefs to the 1997-98 El Ni (n) over tildeo cannot be fully understood without an appreciation of spatial/temporal variability and the historical stresses to which these reefs have been subject over the past 25+ yrs. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, Miami, FL 33149 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Glynn, PW (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. NR 75 TC 225 Z9 236 U1 7 U2 72 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 2001 VL 69 IS 1 BP 79 EP 109 PG 31 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 483UB UT WOS:000171653300007 ER PT J AU Guzman, HM Cortes, J AF Guzman, HM Cortes, J TI Changes in reef community structure after fifteen years of natural disturbances in the Eastern Pacific (Costa Rica) SO BULLETIN OF MARINE SCIENCE LA English DT Article ID GALAPAGOS-ISLANDS ECUADOR; GREAT-BARRIER-REEF; CORAL-REEFS; EL-NINO; ACANTHASTER-PLANCI; TROPICAL PACIFIC; PANAMA; REPRODUCTION; MORTALITY; RECOVERY AB Eastern Pacific coral reefs have been severely disturbed by natural events during the past two decades. We have monitored changes in reef structure and reef recovery after ENSO 1982-83 (starting in 1984), at sixteen permanent plots in four different habitats at Ca (n) over tildeo Island, Costa Rica. Reefs were also severely affected by dinoflagellate blooms in 1985, and by warming events in 1987, 1990-95 and 1997-98. The 1982-83 event caused approximately 100% coral mortality in shallow reef zones at Ca (n) over tildeo Island, particularly of pocilloporid species. Coral recruitment may have coincided with putative larval pulses during the various ENSO events or shortly after, as deduced by the presence of sexual recruits during 1987-88 and widespread sexual recruitment in 1993-94. Mortality of juvenile and adult colonies during the 1997-98 ENSO warming was low (5%), suggesting that populations of massive and branching corals may have been more tolerant of elevated thermal stress than during previous events. Supporting this notion are the Reynolds SST comparative plots for 1982-83 and 1997-98, which indicate similar warming trends and temperature maxima at this locality. Reefs at Ca (n) over tildeo Island are recovering, with significant increases in the number of now sexual recruits. Although 1984 levels of coral cover have not yet been attained island-wide, 70% cover occurs in reef areas on the north side of the island. Other disturbances, such as phytoplankton blooms that affected Pocillopora spp. in all habitats, may have retarded reef regeneration, complicating the course of recovery after the 1982-83 ENSO warming disturbance. C1 Smithsonian Trop Res Inst, Balboa, Ancon, Panama. Univ Costa Rica, CIMAR, San Jose 2060, Costa Rica. Univ Costa Rica, Escuela Biol, San Jose 2060, Costa Rica. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 61 TC 40 Z9 45 U1 1 U2 9 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 2001 VL 69 IS 1 BP 133 EP 149 PG 17 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 483UB UT WOS:000171653300009 ER PT J AU D'Croz, L Mate, JL Oke, JE AF D'Croz, L Mate, JL Oke, JE TI Responses to elevated sea water temperature and UV radiation in the coral Porites lobata from upwelling and non-upwelling environments on the Pacific coast of Panama SO BULLETIN OF MARINE SCIENCE LA English DT Article ID REEF CORALS; BLEACHING EVENT; EASTERN PACIFIC; MORTALITY; ECOLOGY; GULF AB The massive coral species Porites lobata from upwelling and non-upwelling environments on the Pacific coast of Panama was exposed to experimentally elevated water temperature and ambient UV radiation to assess the response of the coral-zooxanthella symbiosis. Our experiment demonstrated that elevated water temperature in the range of 30 to 31 degreesC caused bleaching in P lobata, whereas no significant effect on the coral-zooxanthella symbiosis was observed from exposure to ambient UV radiation. Corals maintained under experimental conditions for 31 d showed a significant decrease in zooxanthellae density and chlorophyll concentration as a function of elevated water temperatures. Changes in the concentrations of chlorophylls a and c(2) per zooxanthella were observed only when corals from the upwelling environment were exposed to high water temperatures. Also, corals from the upwelling environment bleached earlier and more severely than those from the non-upwelling area, Corals returned to ambient conditions showed complete recovery in zooxanthellae density and chlorophyll concentration after 30 d. Bleaching and mortality responses of R lobata indicate a lower threshold to sea warming conditions in coral populations from upwelling Gulf of Panama sites compared to those from the non-upwelling Gulf of Chiriqui. Coral bleaching during the 1997-98 ENSO occurred under similar temperature/time conditions as those examined experimentally in this study, namely 30-31 degreesC per 30 d. C1 Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. Univ Panama, Dept Marine Biol & Limnol, Panama City, Panama. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, Miami, FL 33149 USA. Univ Coll Swansea, Sch Biol Sci, Swansea, W Glam, Wales. RP D'Croz, L (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 46 TC 34 Z9 35 U1 0 U2 12 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 2001 VL 69 IS 1 BP 203 EP 214 PG 12 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 483UB UT WOS:000171653300013 ER PT J AU Hueerkamp, C Glynn, PW D'Croz, L Mate, JL Colley, SB AF Hueerkamp, C Glynn, PW D'Croz, L Mate, JL Colley, SB TI Bleaching and recovery of five eastern Pacific corals in an El Nino-related temperature experiment SO BULLETIN OF MARINE SCIENCE LA English DT Article ID GREAT-BARRIER-REEF; STYLOPHORA-PISTILLATA; POPULATION-DENSITY; GLOBAL CHANGE; MONTASTREA-ANNULARIS; SERIATOPORA-HYSTRIX; FRENCH-POLYNESIA; ZOOXANTHELLAE; GROWTH; MORTALITY AB Coral bleaching events have increased in frequency and severity, due mainly to elevated water temperature associated with El Nino-related warming and a general global warming trend. We experimentally tested the effects of El Nino-like sea temperature conditions on five reef-building corals in the Gulf of Panama. Branching species (Pocillopora damicornis and Pocillopora elegans) and massive species (Porites lobata, Pavona clavus and Pavona gigantea) were exposed to experimentally elevated seawater temperature, similar to1-2 degreesC above ambient, Differences in zooxanthellate coral responses to bleaching and ability to recover were compared and quantified. All corals exposed to high temperature treatment exhibited significant declines in zooxanthellae densities and chlorophyll a concentrations. Pocilloporid species were the most sensitive, being the first to bleach, and suffered the highest mortality (50% after 50 d exposure). Massive coral species demonstrated varying tolerances, but were generally less affected. R gigantea exhibited the greatest resistance to bleaching, with no lethal effects observed. Maximum experimental recovery was observed in R lobata. No signs of recovery occurred in P clavus, as zooxanthellae densities and chlorophyll a concentrations continued to decline under ambient (control) conditions. Experimental coral responses from populations in an upwelling environment are contrasted with field responses observed in a nonupwelling area during the 1997-98 El Nino-Southern Oscillation event. C1 Zentrum Marine Tropenokol, D-28359 Bremen, Germany. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, Miami, FL 33149 USA. Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. RP Hueerkamp, C (reprint author), Zentrum Marine Tropenokol, Fahrenheitstr 6, D-28359 Bremen, Germany. NR 73 TC 28 Z9 30 U1 0 U2 25 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 2001 VL 69 IS 1 BP 215 EP 236 PG 22 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 483UB UT WOS:000171653300014 ER PT J AU Victor, BC Wellington, GM Robertson, DR Ruttenberg, BI AF Victor, BC Wellington, GM Robertson, DR Ruttenberg, BI TI The effect of the El Nino-Southern Oscillation event on the distribution of reef-associated labrid fishes in the eastern Pacific Ocean SO BULLETIN OF MARINE SCIENCE LA English DT Article ID RECRUITMENT; DURATION; SEA AB We surveyed the labrid fishes of the eastern Pacific ocean at multiple sites before, during, and after the 1997-98 ENSO event. Our observations showed that reef fish communities in general did not appear to change markedly as a result of the ENSO. Recruitment of labrids at the Galapagos Islands, Clipperton Atoll and Baja California was generally high near the end of the ENSO, indicating no negative effect on populations. Two labrid species did extend their known range during the ENSO: Stethojulis bandanensis settled onto the tip of Baja California and to the Galapagos Islands, while Thalassoma virens recruited heavily to sites along the southern Sea of Cortez in Baja California. We discuss the oceanographic conditions during the ENSO that may have promoted the range extensions. Adults of these species were present in Baja California and Galapagos 2 yrs after the end of the ENSO. Our observations raise the question why these species do not colonize these sites in normal years, given the potential for long larval durations (up to a maximum of 104 d in T Wrens) and rapid long-distance transport between islands in the region (recruits of S. bandanensis spent only about 32 d in the plankton). C1 Coralreeffish Com, Irvine, CA 92604 USA. Univ Houston, Dept Biol & Biochem, Houston, TX 77204 USA. Smithsonian Trop Res Inst, Panama City, Panama. Univ Calif Santa Barbara, Dept Ecol Evolut & Marine Biol, Santa Barbara, CA 93106 USA. RP Victor, BC (reprint author), Coralreeffish Com, 4051 Glenwood, Irvine, CA 92604 USA. RI Ruttenberg, Benjamin/D-2556-2012 NR 33 TC 15 Z9 18 U1 0 U2 10 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 2001 VL 69 IS 1 BP 279 EP 288 PG 10 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 483UB UT WOS:000171653300018 ER PT J AU Lance, SL Chao, L AF Lance, SL Chao, L TI Sperm-expenditure strategies: the role of mating order, sperm precedence, and non-optimal behavior SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID EJACULATE SIZE; COMPETITION; MAMMALS; VARIES AB We developed a model to examine the amount of sperm that males should transfer to females under different conditions of sperm precedence. Following a previous model (Parker's), we assume the existence of nonrandom mating roles in which there are males that always mate first and others that always mate second. However, we alter Parker's model by introducing the possibility that males are non-optimal in their sperm allocation (because males make mistakes or are interrupted, or because of phenotypic variation among males). We predicted that when males behave optimally, their sperm expenditures will be equal for most levels of sperm precedence, regardless of whether they mate first or second. However, when the possibility that males behave non-optimally is included, we predicted (i) a positive correlation between the allocations of first and second males when there is second-male precedence, (ii) a negative correlation when there is first-male precedence, and (iii) no correlation when there is no precedence. We discuss these and other predictions and provide supporting evidence from the literature. C1 Univ Maryland, Dept Biol, College Pk, MD 20742 USA. RP Lance, SL (reprint author), Smithsonian Inst, Natl Zool Pk, Dept Conservat Biol, 3001 Connecticut Ave NW, Washington, DC 20008 USA. RI Lance, Stacey/K-9203-2013 OI Lance, Stacey/0000-0003-2686-1733 NR 16 TC 0 Z9 0 U1 0 U2 2 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD JUL PY 2001 VL 79 IS 7 BP 1322 EP 1329 DI 10.1139/cjz-79-7-1322 PG 8 WC Zoology SC Zoology GA 456GF UT WOS:000170074200014 ER PT J AU Sidor, CA AF Sidor, CA TI Simplification as a trend in synapsid cranial evolution SO EVOLUTION LA English DT Review DE evolutionary trends; macroevolution; mammal-like reptile; neomorphy; Synapsida; Williston's law ID MAMMAL-LIKE REPTILE; 10 STRUCTURAL STAGES; BODY-SIZE; RANDOM-WALK; COPES RULE; HUMAN HEAD; SKULL; ORIGIN; FOSSIL; PHYLOGENY AB The prevalence and meaning of morphological trends in the fossil record have undergone renewed scrutiny in recent years. Studies have typically focused on trends in body size evolution, which have yielded conflicting results, and have only rarely addressed the question as to whether other morphological characteristics show persistent directionality over long time scales. I investigated reduction in number of skull and lower jaw bones (through loss or fusion) over approximately 150 million years of premammalian synapsid history. The results of a new skull simplification metric (SSM), which is defined as a function of the number of distinct elements, show that pronounced simplification is evident on both temporal (i.e., stratigraphic) and phylogenetic scales. Postcranial evolution exhibits a similar pattern. Skull size, in contrast, bears little relationship with the number of distinct skull bones present. Synapsid skulls carried close to their observed maximum number of elements for most of the Late Carboniferous and Early Permian. The SSM decreased in the Late Permian but, coincident with the radiation of early therapsids, the range of observed SSM values widened during this interval. From derived nonmammalian cynodonts in the Early Triassic through the earliest mammals in the Early Jurassic, both the minimum and maximum SSM decreased. Data from three representative modern mammals (platypus, opossum, and human) suggest that this trend continues through the Cenozoic. In a phylogenetic context, the number of skull elements present in a taxon shows a significant negative relationship with the number of branching events passed from the root of the tree; more deeply embedded taxa have smaller SSM scores. This relationship holds for various synapsid subgroups as well. Although commonly ascribed to the effects of long-term selection, evolutionary trends can alternatively reflect an underlying intrinsic bias in morphological change. In the case of synapsid skull bones (and those of some other tetrapods lineages), the rare production of novel, or neomorphic, elements may have contributed to the observed trend toward skeletal simplification. C1 Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. RP Sidor, CA (reprint author), Smithsonian Inst, Dept Paleobiol, MRC-121, Washington, DC 20560 USA. EM sidor.christian@nmnh.si.edu NR 126 TC 61 Z9 63 U1 1 U2 18 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0014-3820 EI 1558-5646 J9 EVOLUTION JI Evolution PD JUL PY 2001 VL 55 IS 7 BP 1419 EP 1442 PG 24 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 467JU UT WOS:000170699300014 PM 11525465 ER PT J AU McDonald, DB Clay, RP Brumfield, RT Braun, MJ AF McDonald, DB Clay, RP Brumfield, RT Braun, MJ TI Sexual selection on plumage and behavior in an avian hybrid zone: Experimental tests of male-male interactions SO EVOLUTION LA English DT Article DE aggression; asymmetric introgression; character evolution; lek; manakin; shifted clines; speciation ID MALE MATING SUCCESS; BLACK GROUSE; BIRD; TESTOSTERONE; EVOLUTION; SYSTEMS; TRAITS; SPREAD; COLOR AB In western Panama, an unusual hybrid zone exists between white-collared manakins, Manacus candei, and golden-collared manakins, M. vitellinus. Unidirectional introgression of plumage traits from vitellinus into candei has created a region in which all definitively plumaged males have a collar that is lemon-colored. These males are nearly indistinguishable from white-collared candei genetically and morphometrically, but strongly resemble golden-collared vitellinus due to the introgression of secondary sexual plumage, traits, particularly the lemon-colored collar. The introgression could be explained by sexual selection for golden-collared traits or by a series of mechanisms that do not invoke sexual selection (e.g., neutral diffusion, dominant allele). Sexual selection on male-male interactions implies behavioral differences among the plumage forms-specifically that golden- and lemon-collared males should be more aggressive than white-collared males. In contrast, the nonsexual hypotheses predict behavioral similarity between lemon- and white-collared males, based on their nearly identical genetics. We tested the sexual selection hypothesis experimentally, by presenting males with taxidermic mounts of the three forms. As response variables, we monitored vocalizations and attacks on the mounts by replicate subject males. Both golden-collared and lemon-collared males were more likely to attack than were white-collared males, as predicted under sexual selection but not by the nonsexual hypotheses. Lemon-collared males were more vocally reactive than either parental form, contrary to the prediction of the nonsexual hypotheses. Our study demonstrates that sexual selection on male-male interactions may play an important role in the dynamics of character evolution and hybrid zones. C1 Univ Wyoming, Dept Zool & Physiol, Laramie, WY 82071 USA. Univ Cambridge, Dept Zool, Large Anim Res Grp, Cambridge CB2 3EJ, England. Univ Washington, Dept Zool, Seattle, WA 98112 USA. Smithsonian Inst, Lab Mol Systemat, Washington, DC 20560 USA. RP McDonald, DB (reprint author), Univ Wyoming, Dept Zool & Physiol, Laramie, WY 82071 USA. EM dbmcd@uwyo.edu; brumfld@u.washington.edu; braun@onyx.si.edu RI McDonald, David/C-3195-2008; Brumfield, Robb/K-6108-2015 OI McDonald, David/0000-0001-8582-3775; Brumfield, Robb/0000-0003-2307-0688 NR 37 TC 55 Z9 58 U1 2 U2 23 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0014-3820 EI 1558-5646 J9 EVOLUTION JI Evolution PD JUL PY 2001 VL 55 IS 7 BP 1443 EP 1451 PG 9 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 467JU UT WOS:000170699300015 PM 11525466 ER PT J AU Fiske, RS Naka, J Iizasa, K Yuasa, M Klaus, A AF Fiske, RS Naka, J Iizasa, K Yuasa, M Klaus, A TI Submarine silicic caldera at the front of the Izu-Bonin arc, Japan: Voluminous seafloor eruptions of rhyolite pumice SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article DE calderas; polymetallic ores; pumice deposits; pyroclastic deposits; submarine; volcanoes ID VOLCANOS SW PACIFIC; SHIMANE PENINSULA; PYROCLASTIC DEPOSITS; FALL DEPOSITS; CALIFORNIA; DISPERSAL; CANADA; FLOWS; WATER AB Myojin Knell caldera, a submarine rhyolitic center 400 km south of Tokyo, is one of nine silicic calderas along the northern 600 km of the Izu-Bonin(-Ogasawara) are and the first anywhere to receive detailed, submersible-based study. The caldera, slightly smaller than the Crater Lake structure in Oregon, is 6 x 7 km in diameter; its inner walls are 500-900 m high, and it has a remarkably Rat Boor at 1400 m below sea level (mbsl), The caldera collapse volume is similar to 18 km(3), suggesting that more than 40 km(3) of pumiceous tephra may have been erupted at the time the caldera formed. Precaldera seafloor eruptions built a broad volcanic edifice consisting of overlapping composite volcanoes made of rhyolitic lavas, shallow intrusions, and a variety of volcaniclastic deposits-including thick accumulations of rhyolitic pumice erupted at 900-500 mbsl, The caldera-forming eruption produced a 150-200 m deposit of nonwelded, fines-depleted pumice that resembles a colossal layer of popcorn at the top of the caldera wall. Freshly erupted pumice behaved as "sinkers" or "floaters," depending on the environment in which it cooled, The pumice clasts deposited proximally and exposed in the caldera wall were likely quenched in eruption columns that remained below sea level. This pumice ingested seawater and sank as gases filling its vesicles cooled, particularly as steam in its vesicles condensed to liquid water. Some eruption columns may have broken through the sea surface and entered the air, especially during vigorous phases of the caldera-forming eruption. These pumices had the opportunity to ingest air as they cooled, becoming Boaters as they fell back to the sea; these could have been carried distally on the sea surface by the combined effects of ocean currents and wind. The age of the caldera is unknown, but it may be as young as several thousand years. Its magmatic system at depth retains sufficient heat to sustain an actively growing intracaldera Kuroko-type polymetallic sulfide deposit, rich in gold and silver and topped by chimneys emitting fluids as hot as 278 OC, Sufficient time has elapsed, however, for a 250-m-high postcaldera dome to grow on the caldera floor and for the caldera rim to be deeply scalloped by slumping. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. Japan Marine Sci & Technol Ctr, Deep Sea Res Dept, Yokosuka, Kanagawa 237, Japan. Geol Survey Japan, Marine Geol Dept, Tsukuba, Ibaraki 305, Japan. Texas A&M Univ, Ocean Drilling Program, College Stn, TX 77845 USA. RP Fiske, RS (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. EM rfiske@volcano.si.edu NR 54 TC 87 Z9 87 U1 5 U2 23 PU GEOLOGICAL SOC AMER, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0016-7606 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD JUL PY 2001 VL 113 IS 7 BP 813 EP 824 DI 10.1130/0016-7606(2001)113<0813:SSCATF>2.0.CO;2 PG 12 WC Geosciences, Multidisciplinary SC Geology GA 449EB UT WOS:000169670400002 ER PT J AU King, DI Rappole, JH AF King, DI Rappole, JH TI Mixed specks bird flocks its dipterocarp forest of north central Burma (Myanmar) SO IBIS LA English DT Article ID SPECIES FLOCKS; FORAGING FLOCKS; WESTERN MEXICO; BEHAVIOR; PREDATOR; ECOLOGY AB We studied the bird community in deciduous, dipterocarp forest of north-central Burma (Myanmar) during December 1994, March 1996, and January 1997 and 1999. Most members of this community participated in mixed-species flocks. Seventy-three flocks were encountered during our study, containing 52 species. Of these, 25 species occurred in more than 10% of flocks, and were included in our analyses. There were 26 significant correlations among species pairs, 25 of which were positive. Cluster analysis indicated that there were three principal types of flocks: one consisting mostly of small passerines and picids, commonly including Common Wood-Shrike, Small Minivet and White-browed Fantail, among others; a second type consisting mainly of sylviids, e.g. Arctic, Dusky and Radde's Warblers; and a third type which generally centred around Greater and Lesser Necklaced Laughingthrushes. Bird-eating hawks were numerous at these sites, and we witnessed several attacks on flocks during the study. Thus we infer that enhanced protection from predation is an important benefit conferred by flock membership. In contrast, there was little overlap in foraging behaviour among species, suggesting that foraging facilitation is a relatively minor benefit enjoyed by flock members, although we did observe White-browed Fantails and Greater Racket-tailed Drongos kleptoparasitizing other species on occasion. C1 Univ Massachusetts, USDA, Forest Serv, Ne Res Stn, Amherst, MA 01003 USA. Smithsonian Conservat & Res Ctr, Front Royal, VA 22630 USA. RP King, DI (reprint author), Univ Massachusetts, USDA, Forest Serv, Ne Res Stn, Amherst, MA 01003 USA. NR 44 TC 15 Z9 20 U1 0 U2 8 PU BRITISH ORNITHOLOGISTS UNION PI TRING PA C/O NATURAL HISTORY MUSEUM, SUB-DEPT ORNITHOLOGY, TRING HP23 6AP, HERTS, ENGLAND SN 0019-1019 J9 IBIS JI Ibis PD JUL PY 2001 VL 143 IS 3 BP 380 EP 390 DI 10.1111/j.1474-919X.2001.tb04939.x PG 11 WC Ornithology SC Zoology GA 443EJ UT WOS:000169327100003 ER PT J AU Kidwell, PA AF Kidwell, PA TI 'Yours for improvement' - The adding machines of Chicago, 1884-1930 SO IEEE ANNALS OF THE HISTORY OF COMPUTING LA English DT Article AB Between 1884 and 1930, the city of Chicago emerged as a center of manufacture for a new kind of machine, designed especially to assist in ordinary addition. Chicago inventions and products would shape the adding machine industry into the second half of the 20th century. C1 Smithsonian Inst, Washington, DC 20560 USA. RP Kidwell, PA (reprint author), Smithsonian Inst, MRC671,Rm 5125, Washington, DC 20560 USA. NR 55 TC 3 Z9 3 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1058-6180 J9 IEEE ANN HIST COMPUT JI IEEE Ann. Hist. Comput. PD JUL-SEP PY 2001 VL 23 IS 3 BP 3 EP 21 DI 10.1109/85.948903 PG 19 WC Computer Science, Theory & Methods; History & Philosophy Of Science SC Computer Science; History & Philosophy of Science GA 468EF UT WOS:000170744600002 ER PT J AU Richardson, SL AF Richardson, SL TI Syringammina corbicula sp nov (xenophyophorea) from the Cape Verde Plateau, E. Atlantic SO JOURNAL OF FORAMINIFERAL RESEARCH LA English DT Article ID TROPICAL NORTHEAST ATLANTIC; ABYSSAL NE ATLANTIC; 3 EUMELI SITES; DEEP-SEA; BENTHIC FORAMINIFERA; NEW-ZEALAND; PHYTODETRITUS; PROTISTA; BATHYAL; PROTOZOA AB A new xenophyophore species, Syringammina corbicula, is described and illustrated from live specimens collected at 3106 ni on the Cape Verde Plateau, off West Africa. This species is characterized by its epibenthic habitat and the unique basket-like depressions that rim the periphery of its hemispherically-shaped test of anastomosing, agglutinated tubes. Morphological features of the test and cytoplasm of S. corbicula are described in detail and contrasted with other known xenophyophore species grouped in the genus Syringammina. Laboratory observations of the pseudopodia extruded by live individuals are presented and the potential feeding behavior of S. corbicula is discussed briefly. C1 Smithsonian Marine Stn Ft Pierce, Ft Pierce, FL 34949 USA. RP Richardson, SL (reprint author), Smithsonian Marine Stn Ft Pierce, 701 Seaway Dr, Ft Pierce, FL 34949 USA. EM richardson@sms.si.edu NR 80 TC 8 Z9 9 U1 0 U2 1 PU CUSHMAN FOUNDATION FORAMINIFERAL RES PI CAMBRIDGE PA MUSEUM COMPARATIVE ZOOLOGY, DEPT INVERTEBRATE PALEONTOLOGY 26 OXFORD ST, HARVARD UNIV, CAMBRIDGE, MA 02138 USA SN 0096-1191 J9 J FORAMIN RES JI J. Foraminifer. Res. PD JUL PY 2001 VL 31 IS 3 BP 201 EP 209 DI 10.2113/31.3.201 PG 9 WC Paleontology SC Paleontology GA 465JR UT WOS:000170586300004 ER PT J AU Ubelaker, DH Jantz, RL AF Ubelaker, DH Jantz, RL TI Symposium: Essays honoring Ellis R. Kerley, Ph.D. (1924-1998) SO JOURNAL OF FORENSIC SCIENCES LA English DT Biographical-Item DE forensic science; forensic anthropology; Ellis R. Kerley; symposium AB Ellis R. Kerley (1924-1998) published at least 40 works between the years 1957 and 1988. These include four reviews, 10 abstracts, 23 articles and book chapters, and three monographic works. C1 Smithsonian Inst, Natl Museum Nat Hist, Washington, DC 20560 USA. Univ Tennessee, Knoxville, TN USA. RP Ubelaker, DH (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 1 U2 2 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD JUL PY 2001 VL 46 IS 4 BP 771 EP + PG 4 WC Medicine, Legal SC Legal Medicine GA 449LV UT WOS:000169686800001 ER PT J AU Ubelaker, DH AF Ubelaker, DH TI Contributions of Ellis R. Kerley to forensic anthropology SO JOURNAL OF FORENSIC SCIENCES LA English DT Biographical-Item DE forensic science; Ellis R. Kerley; history; forensic anthropology AB Ellis R. Kerley (1924 to 1998) represents an important figure in the history of American forensic anthropology. In research, he is best known for pioneering the microscopic approach to the estimation of age at death from human bone. A university professor for 22 years, Kerley also served as Scientific Director of the Army identification laboratory in Hawaii and worked on many forensic eases. He was a leader in the formation of the physical Anthropology section of the AAFS and the American Board of Forensic Anthropology and held many offices within the AAFS, including President from 1990 to 1991. C1 Smithsonian Inst, Dept Anthropol, NMNH, Washington, DC 20560 USA. RP Ubelaker, DH (reprint author), Smithsonian Inst, Dept Anthropol, NMNH, MRC 112, Washington, DC 20560 USA. NR 1 TC 2 Z9 2 U1 0 U2 3 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD JUL PY 2001 VL 46 IS 4 BP 773 EP 776 PG 4 WC Medicine, Legal SC Legal Medicine GA 449LV UT WOS:000169686800002 PM 11451052 ER PT J AU Kidder, DL Erwin, DH AF Kidder, DL Erwin, DH TI Secular distribution of biogenic silica through the phanerozoic: Comparison of silica-replaced fossils and bedded cherts at the series level SO JOURNAL OF GEOLOGY LA English DT Article ID SURFACE-TEMPERATURE; MASS EXTINCTIONS; LAND PLANTS; PATTERNS; END; MECHANISMS; DIAGENESIS; DIVERSITY; DEPOSITS; SPONGES AB The modern marine silica cycle is dominated by silica-secreting phytoplankton, principally diatoms, but this cycle has evolved considerably during the Phanerozoic. We analyzed the temporal distribution of silica-replaced fossils and bedded chert to determine the influence of factors such as extinctions and climate change on siliceous facies. Trends in silica replacement of fossils match faunal radiations during the Ordovician and Siluro-Devonian, with peaks in silica replacement in the Late Ordovician and Middle Devonian corresponding to peaks in the abundance and diversity of siliceous sponges. Sharp drops in the abundance of silica-replaced fossils and/or bedded cherts coincide with four of the five major mass extinctions. No discernible decrease marks the extinction at the end of the Triassic. We expected peaks in bedded chert deposition during glacial episodes because enhanced ocean circulation should favor more and stronger upwelling. Orogenic episodes, which may trigger continental glaciation, may also increase silica supply and further enhance siliceous deposition during these intervals. The data we have sampled provide mixed results. The Late Ordovician and Late Devonian glaciations do not correspond to peaks in bedded chert abundance, although the increase in bedded cherts relative to silica-replaced fossils during the Carboniferous may reflect a climatic influence. The well-known Middle Miocene circum-Pacific chert event does correspond with a glacial interval. Lows in silica deposition should mark intervals when the ocean was stratified and/or ocean circulation was sluggish. Data from the mid-Cretaceous and Early Triassic appear consistent with this expectation. Following the shift to a diatom-dominated silica cycle in the Late Jurassic and Cretaceous, patterns of chert abundance through time became more volatile and more responsive to external influences on marine silica burial such as icehouse and greenhouse effects. Prior to the diatom radiation, biogenic silica burial was probably more equitably divided between radiolarians and siliceous sponges. This more cosmopolitan control of silica burial may have dampened the effects of climatic factors on silica accumulation, though better resolved data are needed to test this possibility. C1 Ohio Univ, Dept Geol Sci, Athens, OH 45701 USA. Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. RP Kidder, DL (reprint author), Ohio Univ, Dept Geol Sci, Athens, OH 45701 USA. RI Erwin, Douglas/A-9668-2009 NR 69 TC 61 Z9 66 U1 0 U2 9 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0022-1376 J9 J GEOL JI J. Geol. PD JUL PY 2001 VL 109 IS 4 BP 509 EP 522 DI 10.1086/320794 PG 14 WC Geology SC Geology GA 436WR UT WOS:000168959300007 ER PT J AU Cecchi-Pestellini, C Barletti, L Belleni-Morante, A Aiello, S AF Cecchi-Pestellini, C Barletti, L Belleni-Morante, A Aiello, S TI A kinetic model for dust coagulation SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID 2 ELASTIC SPHERES; ADHESIVE CONTACT; EXTINCTION; GRAINS; CLOUDS; RESISTANCE; SIZE AB A Boltzmann-like model is developed for particle transport in presence of coagulation, in which evolution equations for the number densities of small and large particles are derived. Unlike the standard Boltzmann equation, number densities have a dependence on the particle mass, (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Florence, Dipartimento Matemat U Dini, I-50134 Florence, Italy. Univ Florence, Dipartimento Ingn Civile, I-50139 Florence, Italy. RP Cecchi-Pestellini, C (reprint author), Univ Florence, Dipartimento Astron & Sci Spazio, Largo E Fermi 5, I-50125 Florence, Italy. OI Cecchi Pestellini, Cesare/0000-0001-7480-0324 NR 17 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL 1 PY 2001 VL 70 IS 1 BP 1 EP 9 DI 10.1016/S0022-4073(00)00106-0 PG 9 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 438GF UT WOS:000169044700001 ER PT J AU Schroll, S AF Schroll, S TI Hyper mental: Rampant reality 1950-2000; From Salvador Dali to Jeff Koons. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC USA. RP Schroll, S (reprint author), Smithsonian Inst Lib, Washington, DC USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD JUL PY 2001 VL 126 IS 12 BP 83 EP 84 PG 2 WC Information Science & Library Science SC Information Science & Library Science GA 448NB UT WOS:000169632000056 ER PT J AU Kalfatovic, MR AF Kalfatovic, MR TI Fairfield Porter: A catalogue raisonne of the painting, watercolors, and pastels. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC USA. RP Kalfatovic, MR (reprint author), Smithsonian Inst Lib, Washington, DC USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD JUL PY 2001 VL 126 IS 12 BP 84 EP 84 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 448NB UT WOS:000169632000059 ER PT J AU Huss, GR MacPherson, GJ Wasserburg, GJ Russell, SS Srinivasan, G AF Huss, GR MacPherson, GJ Wasserburg, GJ Russell, SS Srinivasan, G TI Aluminum-26 in calcium-aluminum-rich inclusions and chondrules from unequilibrated ordinary chondrites SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID EARLY SOLAR-SYSTEM; ISOTOPIC ANOMALIES; ION MICROPROBE; EXTINCT RADIOACTIVITIES; REFRACTORY INCLUSIONS; ENSTATITE CHONDRITES; ALLENDE INCLUSIONS; OXYGEN ISOTOPES; COSMIC-RAYS; NEBULA AB In order to investigate the distribution of (26)Al in chondrites, we measured aluminum-magnesium systematics in four calcium-aluminum-rich inclusions (CAIs) and eleven aluminum-rich chondrules from unequilibrated ordinary chondrites (UOCs). All four CAIs were found to contain radiogenic (26)Mg ((26)Mg*) from the decay of (26)Al The inferred initial (26)Al/(27)Al ratios for these objects (((26)Al/(27)Al)(o) approximate to 5 x 10(-5)) are indistinguishable from the ((26)Al/(27)Al)(o) ratios found in most CAIs from carbonaceous chondrites. These observations, together with the similarities in mineralogy and oxygen isotopic compositions of the two sets of CAIs, imply that CAIs in UOCs and carbonaceous chondrites formed by similar processes from similar (or the same) isotopic reservoirs, or perhaps in a single location in the solar system. We also found (26)Mg* in two of eleven aluminum-rich chondrules. The ((26)Al/(27)Al)(o) ratio inferred for both of these chondrules is similar to1 x 10(-5), clearly distinct from most CAIs but consistent with the values found in chondrules from type 3.0-3.1 UOCs and for aluminum-rich chondrules from lightly metamorphosed carbonaceous chondrites (similar to0.5 x 10(-5) to similar to2 x 10(-5)). The consistency of the ((26)Al/(27)Al)(o) ratios for CAIs and chondrules in primitive chondrites, independent of meteorite class, implies broad-scale nebular homogeneity with respect to (26)Al and indicates that the differences in initial ratios can be interpreted in terms of formation time. A timeline based on (26)Al indicates that chondrules began to form 1 to 2 Ma after most CAIs formed, that accretion of meteorite parent bodies was essentially complete by 4 Ma after CAIs, and that metamorphism was essentially over in type 4 chondrite parent bodies by 5 to 6 Ma after CAIs formed. Type 6 chondrites apparently did not cool until more than 7 Ma after CAIs formed. This timeline is consistent with (26)Al as a principal heat source for melting and metamorphism. C1 CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. Arizona State Univ, Ctr Meteorite Studies, Tempe, AZ 85287 USA. Nat Hist Museum, Dept Mineral, London SW7 5BD, England. Phys Res Lab, Ahmadabad 380009, Gujarat, India. RP Huss, GR (reprint author), CALTECH, Dept Geol & Planetary Sci, Mail Code 170-25, Pasadena, CA 91125 USA. EM gary.huss@asu.edu RI WASSERBURG, GERALD /F-6247-2011 NR 82 TC 108 Z9 112 U1 1 U2 3 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2001 VL 36 IS 7 BP 975 EP 997 PG 23 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 457RZ UT WOS:000170151800010 ER PT J AU Eberhard, JR Wright, TF Bermingham, E AF Eberhard, JR Wright, TF Bermingham, E TI Duplication and concerted evolution of the mitochondrial control region in the parrot genus Amazona SO MOLECULAR BIOLOGY AND EVOLUTION LA English DT Article DE Amazona; control region; mitochondrial DNA; parrot; concerted evolution; gene duplication; genomic rearrangement ID D-LOOP REGION; DNA; SEQUENCE; GENOME; REPLICATION; ORDER; BIRDS; REARRANGEMENTS; TRANSCRIPTION; ORGANIZATION AB We report a duplication and rearrangement of the mitochondrial genome involving the control region of parrots in the genus Amazona. This rearrangement results in a gene order of cytochrome b/tRNA(Thr)/pND6/pGlu/CR1/tRNA(Pro)/NADH dehydrogenase 6/tRNA(Glu)/CR2/tRNA(Phe)/12s rRNA, where CRI and CR2 refer to duplicate control regions, and pND6 and pGlu indicate: presumed pseudogenes. In contrast to previous reports of duplications involving the control regions of birds, neither copy of the parrot control region shows any indications of degeneration. Rather, both copies contain many of the conserved sequence features typically found in avian control regions, including the goose hairpin, TASs, the F, C, and D boxes, conserved sequence box I (CSB1), and an apparent homolog to the mammalian CSB3. We conducted a phylogenetic analysis of homologous portions of the duplicate control regions from 21 individuals representing four species of Amazona (A. ochrocephala, A. autumnalis, A. farinosa, and A. amazonica) and Pionus chalcopterus. This analysis revealed that an individual's two control region copies (i.e., the paralogous copies) were typically more closely related to one another than to corresponding segments of other individuals: (i.e., the orthologous copies). The average sequence divergence of the paralogous control region copies within an individual was 1.4%, versus a mean value of 4.1% between control region orthologs representing nearest phylogenetic neighbors. No differences were found between the paralogous copies in either the rate or the pattern in which the two copies accumulated base pair changes. This pattern suggests concerted evolution of the two control regions, perhaps through occasional gene conversion events. We estimated that gene conversion events occurred on average every 34,670 +/- 18,400 years based on pairwise distances between the paralogous control region sequences of each individual. Our results add to the growing body of work indicating that under some circumstances duplicated mitochondrial control regions are retained through evolutionary time rather than degenerating and. being lost, presumably due to selection for a small mitochondrial genome. C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Maryland, Dept Biol, College Pk, MD 20742 USA. RP Eberhard, JR (reprint author), Macaulay Lib Nat Sounds, Cornell Lab Ornithol, 159 Sapsucker Woods Rd, Ithaca, NY 14850 USA. NR 36 TC 96 Z9 102 U1 0 U2 5 PU SOC MOLECULAR BIOLOGY EVOLUTION PI LAWRENCE PA PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0737-4038 J9 MOL BIOL EVOL JI Mol. Biol. Evol. PD JUL PY 2001 VL 18 IS 7 BP 1330 EP 1342 PG 13 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 452FG UT WOS:000169846400016 PM 11420371 ER PT J AU Anglin, JR Vardi, A AF Anglin, JR Vardi, A TI Dynamics of a two-mode Bose-Einstein condensate beyond mean-field theory SO PHYSICAL REVIEW A LA English DT Article ID OPEN QUANTUM SYSTEM; OSCILLATIONS; DECOHERENCE; ATOMS AB We study the dynamics of a two-mode Bose-Einstein condensate in the vicinity of a mean-held dynamical instability. Convergence to mean-field theory (MFT), with increasing total number of particles N, is shown to be logarithmically slow. Using a density-matrix formalism rather than the conventional wave-function methods, we derive an improved set of equations of motion for the mean-field plus the fluctuations, which goes beyond MFT and provides accurate predictions for the leading quantum corrections and the quantum break time. We show that the leading quantum corrections appear as decoherence of the reduced single-particle quantum state; we also compare this phenomenon to the effects of thermal noise. Using the rapid dephasing near an instability, we propose a method for the direct measurement of scattering lengths. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Anglin, JR (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. RI Vardi, Amichay/D-8189-2011 OI Vardi, Amichay/0000-0002-8992-2129 NR 26 TC 174 Z9 175 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 2001 VL 64 IS 1 AR 013605 DI 10.1103/PhysRevA.64.063605 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 449XA UT WOS:000169711400093 ER PT J AU Derevianko, A Cote, R Dalgarno, A Jeung, GH AF Derevianko, A Cote, R Dalgarno, A Jeung, GH TI Enhanced cooling of hydrogen by a buffer gas of alkali-metal atoms SO PHYSICAL REVIEW A LA English DT Article ID BOSE-EINSTEIN CONDENSATION; SCATTERING; LITHIUM AB We consider the possibility of enhanced cooling of hydrogen atoms by a buffer gas of alkali-metal atoms Na, K, Rb, and Cs. Ultracold elastic collision cross sections for the Na-H and Rb-H purely spin-polarized pairs are found to be 640 and 860 times larger than that for the H-H pair, respectively. From an analysis of the techniques of production of ultracold sodium and rubidium samples, it seems feasible that the critical conditions for Bose-Einstein condensation of hydrogen could be achieved already at the stage of optical cooling of the sodium or rubidium buffer gas. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Univ Nevada, Dept Phys, Reno, NV 89557 USA. Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Univ Paris 11, Aime Cotton Lab, CNRS, UPR3321, F-91405 Orsay, France. RP Derevianko, A (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RI Derevianko, Andrei/G-8356-2011 NR 13 TC 17 Z9 18 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 2001 VL 64 IS 1 AR 011404 DI 10.1103/PhysRevA.64.011404 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 449XA UT WOS:000169711400009 ER PT J AU Brown, JW AF Brown, JW TI Species turnover in the leafrollers (Lepidoptera : Tortricidae) of plummers island, maryland: Assessing a century of inventory data SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE species inventory; species discovery curve; succession; local extinction; habitat management; conservation ID HABITAT AB During the period 1900 through 1999, 119 species of tortricid moths (leaf-rollers) have been present at one time or another on Plummers Island and the adjacent northern shore of the Potomac River, Maryland. The number of species of leafrollers documented has declined over the last century from 71 in the decade 1900-1909 to 59 in the decade 1990-1999-a reduction of 17% in species richness. Of 71 species recorded from the turn of the century, only 30 are still present. With 41 apparent species extinctions and 29 apparent species colonizations, species turnover is 54%. Because of potential differences in sampling methods (e.g., equipment, diurnal vs, nocturnal, and frequency) between the two decades, "inventories" for the two decades are not strictly comparable. Hence these calculations do not represent precise measurements of changes in the fauna. Nonetheless, it is highly likely that they reflect the overall trend. Of six species described from Plummers Island just after the turn of the century, only one was detected during recent survey work. The most likely explanation for changes in the species composition of the site is faunal response to plant community succession. Since the turn of the last century, vegetation of the island has changed from an open juniper grassland to a submature hickory-maple-oak woodland. The adjacent northern shore, likewise, has undergone considerable succession. The hypothesis that changes in the fauna are the result of succession is consistent with the proposal that habitat maturation is the mechanism behind regional declines of several bird and mammal species that require early successional habitat in the northeastern United States. C1 USDA ARS, PSI,Smithosian Inst, Natl Museum Nat Hist, Systemat Entomol Lab, Washington, DC 20560 USA. RP Brown, JW (reprint author), USDA ARS, PSI,Smithosian Inst, Natl Museum Nat Hist, Systemat Entomol Lab, Washington, DC 20560 USA. NR 25 TC 1 Z9 9 U1 2 U2 2 PU ENTOMOL SOC WASHINGTON PI WASHINGTON PA SMITHSONIAN INSTITUTION DEPT ENTOMOLOGY, WASHINGTON, DC 20560 USA SN 0013-8797 J9 P ENTOMOL SOC WASH JI Proc. Entomol. Soc. Wash. PD JUL PY 2001 VL 103 IS 3 BP 673 EP 685 PG 13 WC Entomology SC Entomology GA 446QG UT WOS:000169523500015 ER PT J AU McKamey, SH AF McKamey, SH TI Review of the Nearctic species of Limotettix (Scleroracus Van Duzee) leafhoppers (Hemiptera : Cicadellidae : Deltocephalinae) SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE Frigartus; vector; cranberry; phytopathogen; Membracoidea AB Descriptions, illustrations, distributions, host plant records, and an identification key are provided for the 32 Nearctic species of the subgenus Limotettix (Scleroracus), tribe Athysanini, which includes at least two species (one Nearctic) known to vector phytopathogens. Two new synonymies are proposed: Frigartus Oman to synonymy under Limotettix (Scleroracus); and Ophiola uhleri speculatus Ball to synonymy under L. (S.) uhleri Ball. One new combination is proposed, L. (S.) frigidus (Ball) (from Frigartus). A lectotype is designated for Athysanus frigidus Ball. C1 USDA ARS, Nat Hist Museum, Smithsonian Inst, PSI,Systemat Entomol Lab, Washington, DC 20560 USA. RP McKamey, SH (reprint author), USDA ARS, Nat Hist Museum, Smithsonian Inst, PSI,Systemat Entomol Lab, Washington, DC 20560 USA. NR 21 TC 1 Z9 2 U1 0 U2 3 PU ENTOMOL SOC WASHINGTON PI WASHINGTON PA SMITHSONIAN INSTITUTION DEPT ENTOMOLOGY, WASHINGTON, DC 20560 USA SN 0013-8797 J9 P ENTOMOL SOC WASH JI Proc. Entomol. Soc. Wash. PD JUL PY 2001 VL 103 IS 3 BP 686 EP 753 PG 68 WC Entomology SC Entomology GA 446QG UT WOS:000169523500016 ER PT J AU Lingafelter, SW Hoebeke, ER AF Lingafelter, SW Hoebeke, ER TI Variation and homology in elytral maculation in the Anoplophora malasiaca/macularia species complex (Coleoptera : Cerambycidae) of Japan and Taiwan SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE Asian Longhorned Beetle; Anoplophora; Cerambycidae; Lamiinae; Lamiini; woodborer; white-spotted citrus longhorn; Japan; Taiwan; systematics; morphoclinal variation AB A description and assessment of elytral maculation and variation is provided for the following Anoplsphora taxa in Japan and Taiwan: Anoplophora malasiaca (Thomson, 1865), A. malasiaca tokunoshimana Samuelson (1965), A. macularia (Thomson, 1865), A. oshimana (Fairmaire, 1895), A. oshimana ryukyensis Breuning and K. Ohbayashi (1964), and A. ogasawaraensis Makihara (1976). Elytral maculae are homologized and compared based on their position to each other and to other elytral features. Because considerable overlap in patterns of maculation; occurs among members of the A. malasiaca/macularia complex, we conclude that elytral maculation alone should not be used to define these taxa. C1 USDA ARS, Nat Hist Museum, Smithsonian Inst, PSI,SWL, Washington, DC 20560 USA. RP Lingafelter, SW (reprint author), USDA ARS, Nat Hist Museum, Smithsonian Inst, PSI,SWL, Washington, DC 20560 USA. NR 17 TC 0 Z9 1 U1 2 U2 4 PU ENTOMOL SOC WASHINGTON PI WASHINGTON PA SMITHSONIAN INSTITUTION DEPT ENTOMOLOGY, WASHINGTON, DC 20560 USA SN 0013-8797 J9 P ENTOMOL SOC WASH JI Proc. Entomol. Soc. Wash. PD JUL PY 2001 VL 103 IS 3 BP 757 EP 769 PG 13 WC Entomology SC Entomology GA 446QG UT WOS:000169523500018 ER PT J AU Baldwin, CC McCosker, JE AF Baldwin, CC McCosker, JE TI Wrasses of the Galapagos Islands, with the description of a new deepwater species of Halichoeres (Perciformes : Labridae) SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE Labridae; Galapagos Islands; submersible; new species; new records ID FISHES AB Halichoeres raisneri, new species, is described from three specimens captured by the Johnson Sea Link submersible at 114-125 m off Wolf Island, Galapagos. Distinctive features of the new species include a dorsally projecting fleshy flap along the posterior three-quarters of the upper lip and the absence of a canine tooth at the corner of the upper jaw. The body color of freshly caught females is pale pink with two yellow stripes and five prominent pink spots above the uppermost stripe. Similarities between the new species and other labrids are discussed, and a key to the 16 nominal species of Labridae known from the Galapagos Islands is provided. Decodon melasma is recorded from the Archipelago for the first time. C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. RP Baldwin, CC (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Vertebrate Zool, MRC 159, Washington, DC 20560 USA. NR 17 TC 1 Z9 2 U1 0 U2 4 PU REVISTA DE BIOLOGIA TROPICAL PI SAN JOSE PA UNIVERSIDAD DE COSTA RICA CIUDAD UNIVERSITARIA, SAN JOSE, COSTA RICA SN 0034-7744 J9 REV BIOL TROP JI Rev. Biol. Trop. PD JUL PY 2001 VL 49 SU 1 BP 89 EP 100 PG 12 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 494YC UT WOS:000172312600012 PM 15260157 ER PT J AU Williams, JT Springer, VG AF Williams, JT Springer, VG TI Review of the south American-Antarctic triplefin fish genus Helcogrammoides (Perciformes : Tripterygiidae) SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE Helcogrammoides; Peru; Chile; identification key; triplefin fishes AB The genus Helcogrammoides comprises three species of small, cryptic shorefishes, H. antarcticus, H. chilensis, and H. cunninghami. All three species inhabit shallow water along exposed rocky coasts. Specimens reported herein extend the known distributions of H. chilensis and H. cunninghami to the vicinity of Lima, Peru, approximately 1 600 km north of their previously reported northernmost records in Chile. Helcogrammoides chilensis and H. cunninghami occur sympatrically over most of their ranges in Peru and Chile and are frequently taken together in the same field collections. Lectotypes are designated for H. chilensis and H. cunninghami. Diagnoses and an identification key are provided for the species. C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. RP Williams, JT (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. NR 9 TC 5 Z9 5 U1 0 U2 4 PU REVISTA DE BIOLOGIA TROPICAL PI SAN JOSE PA UNIVERSIDAD DE COSTA RICA CIUDAD UNIVERSITARIA, SAN JOSE, COSTA RICA SN 0034-7744 J9 REV BIOL TROP JI Rev. Biol. Trop. PD JUL PY 2001 VL 49 SU 1 BP 117 EP + PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 494YC UT WOS:000172312600015 PM 15260160 ER PT J AU Brown, DS Parnell, CE Deluca, EE Golub, L McMullen, RA AF Brown, DS Parnell, CE Deluca, EE Golub, L McMullen, RA TI The magnetic structure of a coronal X-ray bright point SO SOLAR PHYSICS LA English DT Article ID FIELDS; MODEL; RECONNECTION AB X-ray bright points are small dynamic loop structures that are observed all over the solar corona. The high spatial and temporal resolution of the TRACE instrument allows bright points to be studied in much greater detail than previously possible. This paper focuses on a specific bright point which occurred for about 20 hours on 13-14 June 1998 and examines its dynamic structure in detail. This example suggests that the mechanisms that cause bright points to form and evolve are more complex than previously thought. In this case, reconnection probably plays a major part during the formation and brightening of the loop structure. However, later on the foot points rotate injecting twist into the bright point which may cause an instability to occur with dynamic results. C1 Univ St Andrews, Inst Math, St Andrews KY16 9SS, Fife, Scotland. Smithsonian Astrophys Observ, Cambridge, MA 02188 USA. Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. RP Brown, DS (reprint author), Univ St Andrews, Inst Math, St Andrews KY16 9SS, Fife, Scotland. RI DeLuca, Edward/L-7534-2013; OI DeLuca, Edward/0000-0001-7416-2895; Brown, Daniel/0000-0002-1618-8816; Golub, Leon/0000-0001-9638-3082 NR 18 TC 45 Z9 47 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JUL PY 2001 VL 201 IS 2 BP 305 EP 321 DI 10.1023/A:1017907406350 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 471QX UT WOS:000170941000007 ER PT J AU Weller, SG Sakai, AK Wagner, WL AF Weller, SG Sakai, AK Wagner, WL TI Artificial and natural hybridization in Schiedea and Alsinidendron (Caryophyllaceae : Alsinoideae): The importance of phylogeny, genetic divergence, breeding system, and population size SO SYSTEMATIC BOTANY LA English DT Article ID HAWAIIAN-ISLANDS; LIPOCHAETA COMPOSITAE; ADAPTIVE RADIATION; EVOLUTION; PATTERNS; ASTERACEAE; SPECIATION; DROSOPHILA; DIVERSITY AB Artificial hybridizations of Schiedea and Alsinidendron (Caryophyllaceae: Alsinoideae), genera endemic to the Hawaiian Islands, were used to study the effects of phylogenetic relationship, genetic divergence, breeding system, and population size on the ability of species to cross and produce fertile F-1 hybrids. Using 17 taxa, all crosses attempted produced vigorous F-1 hybrids, although pollen fertility of hybrids varied substantially. Fertility of F-1 hybrids was positively related to genetic identity measured using allozyme variability. Fertility of hybrids was not predicted by phylogenetic relationships, estimated from morphological and molecular data. Hybrids between species with dimorphic breeding systems had significantly higher pollen fertility than other combinations, although this effect was not significant when population size was controlled in the analysis. The association of dimorphism and ability to produce fertile F-1 hybrids is probably indirect: dimorphic species of Schiedea occur in large populations and have high genetic identities. Although artificial hybrids are easily produced in the greenhouse, natural hybridization in Schiedea and Alsinidendron is limited, apparently because instances of sympatry are rare and autogamy is often found in one of the two species occurring sympatrically. C1 Univ Calif Irvine, Dept Ecol & Evolutionary Biol, Irvine, CA 92697 USA. Smithsonian Inst, Dept Systemat Biol, Washington, DC 20560 USA. RP Weller, SG (reprint author), Univ Calif Irvine, Dept Ecol & Evolutionary Biol, Irvine, CA 92697 USA. NR 52 TC 15 Z9 16 U1 0 U2 2 PU AMER SOC PLANT TAXONOMISTS PI BRONX PA NEW YORK BOTANICAL GARDEN, BRONX, NY 10458-5126 USA SN 0363-6445 J9 SYST BOT JI Syst. Bot. PD JUL-SEP PY 2001 VL 26 IS 3 BP 571 EP 584 PG 14 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA 472VH UT WOS:000171005300009 ER PT J AU Gaimari, SD Tanasijtshuk, VN AF Gaimari, SD Tanasijtshuk, VN TI A new leucopine genus (Diptera : Chamaemyiidae) with species attacking Ceroplastes wax scales (Hemiptera : Coccidae) in South America SO SYSTEMATIC ENTOMOLOGY LA English DT Article AB A new genus, Echinoleucopis, is proposed within Chamaemyiidae (Diptera). This leucopine genus clearly differs from other Chamaemyiidae in the high lunule, reduction and fusion of spermathecae in females and rounded form of puparia. Within Echinoleucopis, five new species (bennetti, grioti, iota, macula and nigrolinea) are described, in addition to lectotype designation, redescription and recombination for the type species of the genus, Leucopina ceroplastophaga Blanchard. Phylogenetic relationships among the included taxa are hypothesized. All known species of the genus are from South America and are predators on eggs within an ovisac of wax scales in genus Ceroplastes Gray (Hemiptera: Coccidae). C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol MRC 169, Washington, DC 20560 USA. Russian Acad Sci, Inst Zool, St Petersburg 199034, Russia. RP Gaimari, SD (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol MRC 169, Washington, DC 20560 USA. NR 33 TC 3 Z9 3 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0307-6970 J9 SYST ENTOMOL JI Syst. Entomol. PD JUL PY 2001 VL 26 IS 3 BP 311 EP 328 DI 10.1046/j.1365-3113.2001.00156.x PG 18 WC Evolutionary Biology; Entomology SC Evolutionary Biology; Entomology GA 452TB UT WOS:000169874000003 ER PT J AU Davidson, JF AF Davidson, JF TI More than munitions: Women, work and the engineering industries, 1900-1950. SO TECHNOLOGY AND CULTURE LA English DT Book Review C1 Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. RP Davidson, JF (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU JOHNS HOPKINS UNIV PRESS PI BALTIMORE PA JOURNALS PUBLISHING DIVISION, 2715 NORTH CHARLES ST, BALTIMORE, MD 21218-4319 USA SN 0040-165X J9 TECHNOL CULT JI Technol. Cult. PD JUL PY 2001 VL 42 IS 3 BP 580 EP 581 DI 10.1353/tech.2001.0103 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA 458JC UT WOS:000170190400020 ER PT J AU Bourke, TL Myers, PC Robinson, G Hyland, AR AF Bourke, TL Myers, PC Robinson, G Hyland, AR TI New OH Zeeman measurements of magnetic field strengths in molecular clouds SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : individual (RCW 38, RCW 57); ISM : kinematics and dynamics; ISM : magnetic fields; ISM : molecules ID H-II REGIONS; INTERSTELLAR DUST CLOUDS; SOUTHERN MILKY-WAY; 18 CM OBSERVATIONS; DARK CLOUD; CHAMELEON-I; STAR-FORMATION; IRAS SOURCES; GALACTIC OH; CO SURVEY AB We present the results of a new survey of 23 molecular clouds for the Zeeman effect in OH undertaken with the Australia Telescope National Facility Parkes 64 m radio telescope and the National Radio Astronomy Observatory Green Bank 43 m radio telescope. The Zeeman effect was clearly detected in the cloud associated with the H II region RCW 38, with a field strength of 38 +/- 3 muG, and possibly detected in a cloud associated with the H II region RCW 57, with a field strength of -203 +/- 24 muG. The remaining 21 measurements give formal upper limits to the magnetic field strength, with typical 1 sigma sensitivities less than 20 muG. For 22 of the molecular clouds we are also able to determine the column density of the gas in which we have made a sensitive search for the Zeeman effect. We combine these results with previous Zeeman studies of 29 molecular clouds, most of which were compiled by Crutcher, for a comparison of theoretical models with the data. This comparison implies that if the clouds can be modeled as initially spherical with uniform magnetic fields and densities that evolve to their final equilibrium state assuming flux freezing, then the typical cloud is magnetically supercritical, as was found by Crutcher. If the clouds can be modeled as highly flattened sheets threaded by uniform perpendicular fields, then the typical cloud is approximately magnetically critical, in agreement with Shu et al., but only if the true values of the field for the nondetections are close to the 3 sigma upper limits. If instead these values are significantly lower (for example, similar to the 1 sigma limits), then the typical cloud is generally magnetically supercritical. When all observations of the Zeeman effect are considered, the single-dish detection rate of the OH Zeeman effect is relatively low. This result may be due to low mean field strengths, but a more realistic explanation may be significant field structure within the beam. As an example, for clouds associated with H II regions, the molecular gas and magnetic field may be swept up into a thin shell, which results in a nonuniform field geometry and measurements of the beam-averaged field strength, which are significantly lower than the true values. This effect makes it more difficult to distinguish magnetically subcritical and supercritical clouds. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ New S Wales, Australian Def Force Acad, Univ Coll, Sch Phys, Canberra, ACT 2600, Australia. So Cross Univ, Off Vice Chancellor, Lismore, NSW 2480, Australia. RP Bourke, TL (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 42, Cambridge, MA 02138 USA. EM tbourke@cfa.harvard.edu; pmyers@cfa.harvard.edu; garry@ph.adfa.edu.au NR 93 TC 113 Z9 113 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 JUN 29 PY 2001 VL 554 IS 2 BP 916 EP 932 DI 10.1086/321405 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XL UT WOS:000169943400020 ER PT J AU Pettini, M Shapley, AE Steidel, CC Cuby, JG Dickinson, M Moorwood, AFM Adelberger, KL Giavalisco, M AF Pettini, M Shapley, AE Steidel, CC Cuby, JG Dickinson, M Moorwood, AFM Adelberger, KL Giavalisco, M TI The rest-frame optical spectra of Lyman break galaxies: Star formation, extinction, abundances, and kinematics SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : abundances; galaxies : evolution; galaxies : starburst; infrared : galaxies ID ALPHA LUMINOSITY FUNCTION; H-II REGIONS; HIGH-REDSHIFT; LY-ALPHA; FORMING GALAXIES; FIELD GALAXIES; MS 1512-CB58; CHEMICAL ABUNDANCES; STELLAR POPULATIONS; FORMATION RATES AB We present the first results of a spectroscopic survey of Lyman break galaxies (LBGs) in the near-infrared aimed at detecting the emission lines of [O II], [O III], and H beta from the H II regions of normal star-forming galaxies at z similar or equal to 3. From observations of 15 objects with the Keck telescope and the Very Large Telescope augmented with data from the literature for an additional four objects, we reach the following main conclusions. The rest-frame optical properties of LBGs at the bright end of the luminosity function are remarkably uniform, their spectra are dominated by emission lines, [O III] is always stronger than H beta and [O II], and projected velocity dispersions are between 50 and 115 km s(-1). Contrary to expectations, the star formation rates deduced from the H beta luminosity are on average no larger than those implied by the stellar continuum at 1500 Angstrom; presumably any differential extinction between rest-frame optical and UV wavelengths is small compared to the relative uncertainties in the calibrations of these two star formation tracers. For the galaxies in our sample, the abundance of oxygen can only be determined to within 1 order of magnitude without recourse to other emission lines ([N II] and H alpha), which are generally not available. Even so, it seems well established that LBGs are the most metal-enriched structures at z similar or equal to 3, apart from quasi-stellar objects, with abundances greater than about 1/10 solar and generally higher than those of damped Ly alpha systems at the same epoch. They are also significantly overluminous for their metallicities; this is probably an indication that their mass-to-light ratios are low compared to present-day galaxies. At face value, the measured velocity dispersions imply virial masses of about 10(10) M(.) within half-light radii of 2.5 kpc. The corresponding mass-to-light ratios, M/L approximate to 0.15 in solar units, are indicative of stellar populations with ages between 10(8) and 10(9) yr, consistent with the UV-optical spectral energy distributions. However, we are unable to establish conclusively whether or not the widths of the emission lines reflect the motions of the H II regions within the gravitational potential of the galaxies, even though in two cases we see hints of rotation curves. All 19 LBGs observed show evidence for galactic-scale superwinds; such outflows have important consequences for regulating star formation, distributing metals over large volumes, and allowing Lyman continuum photons to escape and ionize the intergalactic medium. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. European So Observ, Santiago 19, Chile. Space Telescope Sci Inst, Baltimore, MD 21218 USA. European So Observ, D-85748 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Pettini, M (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. NR 77 TC 607 Z9 610 U1 1 U2 6 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 JUN 29 PY 2001 VL 554 IS 2 BP 981 EP 1000 DI 10.1086/321403 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XL UT WOS:000169943400024 ER PT J AU Fabbiano, G Zezas, A Murray, SS AF Fabbiano, G Zezas, A Murray, SS TI Chandra observations of "the Antennae" galaxies (NGC 4038/9) SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 4038/9); galaxie : interactions; galaxies : peculiar; X-rays : galaxies ID X-RAY-EMISSION; HIGH-RESOLUTION CAMERA; SPIRAL GALAXIES; STAR-CLUSTERS; NGC 4038/39; M82; GAS AB We report the results of a deep Chandra ACIS pointing at the merging system NGC 4038/9. We detect an extraordinarily luminous population of X-ray sources, with luminosity well above that of XRBs in M31 and the Milky Way. If these sources are unbeamed XRBs, our observations may point to them being 10-(a few) 100 M(circle dot) black hole counterparts. We detect an X-ray bright hot ISM, with features including bright superbubbles associated with the actively star-forming knots, regions where hot and warm (H alpha) ISM intermingle, and a large-scale outflow. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Fabbiano, G (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Zezas, Andreas/C-7543-2011 OI Zezas, Andreas/0000-0001-8952-676X NR 36 TC 182 Z9 182 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 JUN 29 PY 2001 VL 554 IS 2 BP 1035 EP 1043 DI 10.1086/321397 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XL UT WOS:000169943400028 ER PT J AU Sanz-Forcada, J Brickhouse, NS Dupree, AK AF Sanz-Forcada, J Brickhouse, NS Dupree, AK TI Extreme Ultraviolet Explorer observations of lambda Andromedae SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : spectroscopic; stars : coronae; stars : flare; stars : individual (lambda Andromedae); X-rays : stars ID RS-CANUM-VENATICORUM; TRANSITION-REGION STRUCTURE; LOCAL INTERSTELLAR-MEDIUM; EMISSION MEASURE; AR-LACERTAE; FLARE TEMPERATURE; STELLAR FLARES; II-PEGASI; BINARIES; STARS AB Extreme-ultraviolet spectra (70-740 Angstrom) and light curves (75-175 Angstrom )of the spectroscopic binary system lambda Andromedae (HD 222107) were obtained with the Extreme Ultraviolet Explorer (EUVE) satellite in 1997 July and August. Two flares were detected during the observations that spanned 15 days, or almost 3/4 of the orbital period of 20.5 days, with a total exposure time of 283 ks. The emission measure distribution (EMD) of lambda And derived from a line-based analysis shows an increasing slope with temperatures over the range log T-e (K) = 6.5-7.3 as well as a remarkable narrow enhancement or "bump" around log T-e (K) = 6.9. Both flaring and quiescent EUVE spectra were obtained. During the flares, small changes were detected in both the general slope of the EMD and the height of the bump, but the bump remained very stable in its temperature. Electron densities of (cm(-3)) similar to 12.3 are indicated at temperatures of log T-e (K) = 7 using Fe XXI and Fe XXII emission features, and those densities increase to log N-e (cm(-3)) similar to 12.9 during flaring episodes. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Complutense Madrid, Dept Astrofis, E-28040 Madrid, Spain. RP Sanz-Forcada, J (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Sanz-Forcada, Jorge/C-3176-2017 OI Sanz-Forcada, Jorge/0000-0002-1600-7835 NR 36 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 JUN 29 PY 2001 VL 554 IS 2 BP 1079 EP 1086 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XL UT WOS:000169943400032 ER PT J AU Testi, L Natta, A Shepherd, DS Wilner, DJ AF Testi, L Natta, A Shepherd, DS Wilner, DJ TI Constraints on properties of the protoplanetary disks around UX orionis and CQ Tauri SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; radio continuum : stars; stars : formation ID SPECTRAL ENERGY-DISTRIBUTIONS; HERBIG-AE/BE STARS; INTERMEDIATE-MASS STARS; PASSIVE T-TAURI; CIRCUMSTELLAR DISKS; HIGH-RESOLUTION; AE SYSTEMS; DUST; GAS; ACCRETION AB We present Very Large Array observations of the intermediate-mass pre-main-sequence stars UX Ori and CQ Tau at 7 mm, 3.6 cm, and 6 cm. These stars are members of the UX Ori variability class, where the origin of optical variability is thought to derive from inhomogeneities in circumstellar disks. Both stars are detected at 7 mm but not at longer wavelengths, which confirms that the millimeter emission is dominated by dust. The UX Ori system exhibits a remarkably flat spectral index in the millimeter range, with alpha (mm) similar to 2 (F-nu proportional to nu (alpha mm))Two different disk models can reproduce this property: (1) a physically small disk with optically thick emission, truncated at a radius of about 30 AU, or (2) a massive (similar to0.3-1 M-circle dot) disk mainly composed of dust particles grown to radii of 10 cm ("pebbles"). The observations do not spatially resolve the 7 mm emission. We discuss implications of these two models and suggest observational tests that will discriminate between them. The CQ Tau system exhibits a spectral index in the millimeter range of alpha (mm) similar to 2.6 consistent with values commonly found for disks around pre-main-sequence stars. The observations marginally resolve the 7 mm emission as an elongated structure with full width at half-maximum of 2."4 x 1."1 (240 x 110 AU at 100 pc distance). The size and inclination of similar to 63 degrees (implied by circular symmetry) are consistent with flared disk models that have previously been suggested to explain the optical colors and polarization properties. C1 Osserv Astrofis Arcetri, I-50125 Florence, Italy. Natl Radio Astron Observ, Socorro, NM 87801 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Testi, L (reprint author), Osserv Astrofis Arcetri, Largo E Fermi 5, I-50125 Florence, Italy. NR 41 TC 59 Z9 60 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 JUN 29 PY 2001 VL 554 IS 2 BP 1087 EP 1094 DI 10.1086/321406 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XL UT WOS:000169943400033 ER PT J AU Cohn, JD Kochanek, CS McLeod, BA Keeton, CR AF Cohn, JD Kochanek, CS McLeod, BA Keeton, CR TI Constraints on galaxy density profiles from strong gravitational lensing: The case of B1933+503 SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; galaxies : halos; galaxies : structure; gravitational lensing ID INFRARED EINSTEIN RING; COLD DARK-MATTER; SPHERICAL GALAXIES; HUBBLE CONSTANT; MASS DISTRIBUTIONS; SYSTEM B1933+503; MODELS; LENSES; PG-1115+080; FAMILY AB We consider a wide range of parametric mass models for B1933+503, a 10-image radio lens, and identify shared properties of the models with the best fits. The approximate rotation curves vary by less than 8.5% from the average value between the innermost and the outermost image (1.5-4.1 h(-1) kpc) for models within 1 sigma of the best fit, and the radial dependence of the shear strength and angle also have common behavior for the best models. The time delay between images 1 and 6, the longest delay between the radio cores, is Deltat = 10.6(-1.1)(+2.4) days (Omega (0) = 0.3, lambda (0) = 0.7) days including all the modeling uncertainties Deeper infrared observations, to more precisely register the lens galaxy with the radio images and to measure the properties of the Einstein ring image of the radio source's host galaxy, would significantly improve the model constraints and further reduce the uncertainties in the mass distribution and time delay. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Cohn, JD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 60 TC 79 Z9 79 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 JUN 29 PY 2001 VL 554 IS 2 BP 1216 EP 1226 DI 10.1086/321412 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XL UT WOS:000169943400044 ER PT J AU Jain, RK Bailyn, CD Orosz, JA McClintock, JE Remillard, RA AF Jain, RK Bailyn, CD Orosz, JA McClintock, JE Remillard, RA TI Multiwavelength observations of the black hole candidate XTE J1550-564 during the 2000 outburst SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; stars : individual (XTE J1550-564); X-rays : stars ID STELLAR AB We report optical, infrared, and X-ray light curves for the outburst, in 2000, of the black hole candidate XTE J1550-564. We find that the start of the outburst in the H and V bands precedes that seen in the Rossi X-Ray Timing Explorer All-Sky Monitor by and days, respectively; a similar delay has been 11.5 +/- 0.9 and 8.8 +/- 0.6 days, respectively; a similar delay has been observed in two other systems. About 50 days after the primary maxima in the VIH light curves, we find secondary maxima, most prominently in H. This secondary peak is absent in the X-ray light curve but coincides with a transition to the low/hard state. We suggest that this secondary peak may be due to nonthermal emission associated with the formation of a jet. C1 Yale Univ, Dept Phys, New Haven, CT 06520 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Univ Utrecht, Sterrenkundig Inst, NL-3508 TA Utrecht, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Jain, RK (reprint author), Yale Univ, Dept Phys, POB 208120, New Haven, CT 06520 USA. NR 29 TC 60 Z9 60 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 JUN 29 PY 2001 VL 554 IS 2 BP L181 EP L184 DI 10.1086/321700 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XN UT WOS:000169943600013 ER PT J AU Jha, S Pahre, MA Garnavich, PM Calkins, ML Kilgard, RE Matheson, T McDowell, JC Roll, JB Stanek, KZ AF Jha, S Pahre, MA Garnavich, PM Calkins, ML Kilgard, RE Matheson, T McDowell, JC Roll, JB Stanek, KZ TI The redshift of the optical transient associated with GRB 010222 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : distances and redshifts; galaxies : ISM; gamma rays : bursts ultraviolet : galaxies ID GAMMA-RAY BURST; AFTERGLOW; COUNTERPART; EXTINCTION; GALAXIES; EMISSION; DUST AB The gamma-ray burst (GRB) 010222 is the brightest GRB detected to date by the BeppoSAX satellite. Prompt identification of the associated optical transient (OT) allowed for spectroscopy with the Tillinghast 1.5 m telescope at F. L. Whipple Observatory while the source was still relatively bright (R similar or equal to 18.6 mag), within 5 hr of the burst. The OT shows a blue continuum with many superposed absorption features corresponding to metal lines at z = 1.477, 1.157, and possibly also 0.928. The redshift of GRB 010222 is therefore unambiguously placed at z greater than or equal to 1.477. The high number of Mg II absorbers and especially the large equivalent widths of the Mg II, Mg I, and Fe II absorption lines in the z = 1.477 system further argue either for a very small impact parameter or that the z = 1.477 system is the GRB host galaxy itself. The spectral index of the OT is relatively steep, F-v proportional to nu (-0.89 +/- 0.03), and this cannot be caused by dust with a standard Galactic extinction law in the z = 1.477 absorption system. This spectroscopic identification of the redshift of GRB 010222 shows that prompt and well-coordinated follow-up of bright GRBs can be successful even with telescopes of modest aperture. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RP Jha, S (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 41 TC 46 Z9 46 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 JUN 29 PY 2001 VL 554 IS 2 BP L155 EP L158 DI 10.1086/321709 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XN UT WOS:000169943600007 ER PT J AU Mahdavi, A Geller, MJ AF Mahdavi, A Geller, MJ TI The L-x-sigma relation for galaxies and clusters of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general X-rays : galaxies ID RAY; SAMPLE; TEMPERATURES; LUMINOSITY; PARAMETERS; EVOLUTION; ENTROPY; MASS; GAS AB We demonstrate that individual elliptical galaxies and clusters of galaxies form a continuous X-ray luminosity-velocity dispersion (L-x-sigma) relation. Our samples of 280 clusters and 57 galaxies have L-x proportional to sigma (4.4) and L-x proportional to sigma (10), respectively. This unified relation spans 8 orders of magnitude in and is fully consistent with the observed L - L and theoretical luminosity-temperature scaling laws. Our results support the notion that galaxies and clusters of galaxies are the luminous tracers of similar dark matter halos. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mahdavi, A (reprint author), Harvard Smithsonian Ctr Astrophys, MS 10,60 Garden St, Cambridge, MA 02138 USA. NR 36 TC 48 Z9 48 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 JUN 29 PY 2001 VL 554 IS 2 BP L129 EP L132 DI 10.1086/321710 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XN UT WOS:000169943600001 ER PT J AU Tennant, AF Becker, W Juda, M Elsner, RF Kolodziejczak, JJ Murray, SS O'Dell, SL Paerels, F Swartz, DA Shibazaki, N Weisskopf, MC AF Tennant, AF Becker, W Juda, M Elsner, RF Kolodziejczak, JJ Murray, SS O'Dell, SL Paerels, F Swartz, DA Shibazaki, N Weisskopf, MC TI Discovery of X-ray emission from the crab pulsar at pulse minimum SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (Crab Nebula) pulsars : individual (Crab Pulsar) radiation mechanisms : nonthermal stars : neutron; X-rays : general ID COOLING NEUTRON-STARS; ACCRETED ENVELOPES; THERMAL EVOLUTION; CASSIOPEIA; RADIATION; NEBULA AB The Chandra X-Ray Observatory observed the Crab pulsar using the Low-Energy Transmission Grating with the High-Resolution Camera. Time-resolved zeroth-order images reveal that the pulsar emits X-rays at all pulse phases. Analysis of the flux at minimum-most likely nonthermal in origin-places an upper limit (T(infinity) < 2.1 MK) on the surface temperature of the underlying neutron star. In addition, analysis of the pulse profile establishes that the error in the Chandra-determined absolute time is quite small, -0.2 +/- 0.1 ms. C1 NASA, Dept Space Sci, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. NASA, Univ Space Res Assoc, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Rikkyo Univ, Tokyo 1718501, Japan. RP Tennant, AF (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; Juda, Michael/0000-0002-4375-9688 NR 26 TC 45 Z9 45 U1 0 U2 2 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 JUN 29 PY 2001 VL 554 IS 2 BP L173 EP L176 DI 10.1086/321718 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453XN UT WOS:000169943600011 ER PT J AU Balakrishnan, N Alekseyev, AB Buenker, RJ AF Balakrishnan, N Alekseyev, AB Buenker, RJ TI Ab initio quantum mechanical investigation of the photodissociation of HI and DI SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DOPPLER SPECTROSCOPY; UV PHOTODISSOCIATION; HYDROGEN IODIDE; STATE; HL; PHOTOFRAGMENTATION; DYNAMICS; PHOTOLYSIS; ABSORPTION; CONTINUUM AB The photoabsorption spectra of HI and DI are computed using ab initio potential curves and transition dipole moments. Partial absorption cross-sections and quantum yields for the production of the ground state (P-2(3/2)) and the excited spin-orbit state (P-2(1/2)) of iodine are calculated using the time-dependent wave packet formalism as functions of the excitation energy. Very good overall agreement with experimental data is obtained for the band total absorption spectrum and for the I(P-2(1/2)) quantum yield. The spin-rotational coupling of the a(3)Pi (0) and A(1)Pi (1) states is estimated for the first time and is shown to play a negligible role in the HI photodissociation. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Berg Univ Gesamthsch Wuppertal, Fachbereich Theoret Chem 9, D-42097 Wuppertal, Germany. RP Balakrishnan, N (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 25 TC 27 Z9 27 U1 1 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 29 PY 2001 VL 341 IS 5-6 BP 594 EP 600 DI 10.1016/S0009-2614(01)00514-0 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 446WR UT WOS:000169537600032 ER PT J AU Balakrishnan, N Dalgarno, A AF Balakrishnan, N Dalgarno, A TI Chemistry at ultracold temperatures SO CHEMICAL PHYSICS LETTERS LA English DT Article ID POTENTIAL-ENERGY SURFACES; F+H-2 REACTION; F+H-2->HF+H REACTION; ISOTOPIC VARIANTS; CROSS-SECTIONS; RATE CONSTANTS; MOLECULES; SCATTERING; DYNAMICS; STATE AB The reaction F + H-2 --> FH + H is studied quantum mechanically at ultralow temperatures. The low temperature limit of its rate coefficient is controlled by the attractive van der Waals interaction and quantum mechanical threshold effects. When the fine-structure splitting of the fluorine atom is neglected, the rate coefficient passes through a minimum near 10 K and then increases to a constant value of 1.25 x 10(-12) cm(3) s(-1) at temperatures below 0.2 K. When it is included the ultralow temperature limit is reduced to 2.5 x 10(-13) cm(3) s(-1). The long duration of the collision allows tunneling through the repulsive barrier even in the limit of zero temperature. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Balakrishnan, N (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 35 TC 187 Z9 193 U1 2 U2 24 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 29 PY 2001 VL 341 IS 5-6 BP 652 EP 656 DI 10.1016/S0009-2614(01)00515-2 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 446WR UT WOS:000169537600040 ER PT J AU Dohm, JM Anderson, RC Baker, VR Ferris, JC Rudd, LP Hare, TM Rice, JW Casavant, RR Strom, RG Zimbelman, JR Scott, DH AF Dohm, JM Anderson, RC Baker, VR Ferris, JC Rudd, LP Hare, TM Rice, JW Casavant, RR Strom, RG Zimbelman, JR Scott, DH TI Latent outflow activity for western Tharsis, Mars: Significant flood record exposed SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID PATHFINDER LANDING SITE; MARTIAN NORTHERN PLAINS; TECTONIC HISTORY; ANCIENT OCEANS; CHANNELS; REGION; ICE; GEOLOGY; GENERATION; EVOLUTION AB Observations permitted by the newly acquired Mars Observer Laser Altimeter data have revealed a system of gigantic valleys northwest of the huge Martian shield volcano, Arsia Mons, in the western hemisphere of Mars (northwestern slope valleys (NSVs)). These features, which generally correspond spatially to gravity lows, are obscured by veneers of materials including volcanic lava flows, air fall deposits, and eolian materials. Geologic investigations of the Tharsis region suggest that the system of gigantic valleys predates the construction of Arsia Mons and its extensive associated lava flows of mainly late Hesperian and Amazonian age and coincides stratigraphically with the early development of the outflow channels that debouch into Chryse Planitia. Similar to the previously identified outflow channels, which issued tremendous volumes of water into topographic lows such as Chryse Planitia, the NSVs potentially represent flooding of immense magnitude and, as such, a source of water for a northern plains ocean. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Jet Prop Lab, Pasadena, CA 91109 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. RP Dohm, JM (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. RI Dohm, James/A-3831-2014; OI Hare, Trent/0000-0001-8842-389X NR 77 TC 42 Z9 42 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 2001 VL 106 IS E6 BP 12301 EP 12314 DI 10.1029/2000JE001352 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 445ZJ UT WOS:000169488200002 ER PT J AU Takakuwa, S Kawaguchi, K Mikami, H Saito, M AF Takakuwa, S Kawaguchi, K Mikami, H Saito, M TI The ortho-to-para ratio and the chemical properties of C3H2 in dark cloud cores SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN LA English DT Article DE ISM : abundances; ISM : individual (TMC-1C, L 1527) ISM : molecules ID MOLECULAR CLOUDS; DENSE CORES; PHYSICAL CONDITIONS; FORMALDEHYDE ORTHO; CYCLOPROPENYLIDENE; CHEMISTRY; RING; (HCO+)-C-13; EMISSION; REGIONS AB We have observed cyclic C3H2 (J(KaKc) = 2(12)-1(01), 2(02)-1(11), 3(12)-3(03)) lines at the 3 mm wavelength region toward the starless TMC-IC cloud and the protostellar core of L 1527 with the 45 m telescope at Nobeyama Radio Observatory. in both clouds, the 2(12)-1(01) and 2(02)-1(11) lines are strongly detected, while the 3(12)-3(03) line is only detected toward the center of the protostellar core L 1527. From our statistical equilibrium analyses of the ortho-C3H2 (2(12)-1(01)) and the para-C3H2 (2(02)-1(11)) lines, the ortho-to-para ratios of C3H2 are determined to be 2.4 +/- 0.1 and 2.5 +/- 0.5 in TMC-1C and L 1527? respectively. These values are lower than the statistical value of 3, although the error of the ratio in L 1527 is large. Since thermal equilibrium with a dust temperature of 10 K still gives a ratio of 3 in C-C3H2, this result should suggest the lower ortho-to-para ratio of the precursor molecule, c-C3H3+, which is thought to be mainly produced by C3H+ + H-2. Thus, we conclude that the lower ortho-to-para ratio of c-C3H2 is due to a lower ortho-to-para ratio of H-2 than the statistical value. C1 Natl Astron Observ, Nobeyama Radio Observ, Minamisa Ku, Nagano 3841305, Japan. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Acad Sinica, Inst Astron & Astrophys, POB 1-87, Taipei 11529, Taiwan. EM takakuwa@asiaa.sinica.edu.tw RI Kawaguchi, Kentarou/B-1758-2011 OI Kawaguchi, Kentarou/0000-0003-1067-1839 NR 38 TC 13 Z9 13 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0004-6264 EI 2053-051X J9 PUBL ASTRON SOC JPN JI Publ. Astron. Soc. Jpn. PD JUN 25 PY 2001 VL 53 IS 2 BP 251 EP 257 DI 10.1093/pasj/53.2.251 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 426EH UT WOS:000168336500011 ER PT J AU Takakuwa, S Kawaguchi, K Mikami, H Saito, M AF Takakuwa, S Kawaguchi, K Mikami, H Saito, M TI The ortho-to-para ratio and the chemical properties of C3H2 in dark cloud cores (vol 53, pg 251, 2001) SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN LA English DT Correction C1 Natl Astron Observ, Nobeyama Radio Observ, Minamisa Ku, Nagano 3841305, Japan. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Natl Astron Observ, Nobeyama Radio Observ, Minamisa Ku, Nagano 3841305, Japan. RI Kawaguchi, Kentarou/B-1758-2011 OI Kawaguchi, Kentarou/0000-0003-1067-1839 NR 1 TC 0 Z9 0 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0004-6264 EI 2053-051X J9 PUBL ASTRON SOC JPN JI Publ. Astron. Soc. Jpn. PD JUN 25 PY 2001 VL 53 IS 3 BP 577 EP 577 DI 10.1093/pasj/53.3.577 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 447VW UT WOS:000169594000024 ER PT J AU de Queiroz, K Donoghue, M AF de Queiroz, K Donoghue, M TI Taxing debate for taxonomists SO SCIENCE LA English DT Letter C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. Yale Univ, Dept Ecol & Evolutionary Biol, New Haven, CT 06520 USA. RP de Queiroz, K (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 0 TC 1 Z9 2 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 22 PY 2001 VL 292 IS 5525 BP 2249 EP 2249 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 445KD UT WOS:000169455900022 PM 11424941 ER PT J AU Piperno, DR AF Piperno, DR TI Archaeology - On maize and the sunflower SO SCIENCE LA English DT Editorial Material C1 Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archaeol, Balboa, Panama. RP Piperno, DR (reprint author), Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archaeol, Box 2072, Balboa, Panama. NR 10 TC 10 Z9 10 U1 1 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 22 PY 2001 VL 292 IS 5525 BP 2260 EP 2261 DI 10.1126/science.1062689 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 445KD UT WOS:000169455900034 PM 11423640 ER PT J AU Grindlay, JE Heinke, C Edmonds, PD Murray, SS AF Grindlay, JE Heinke, C Edmonds, PD Murray, SS TI High-resolution X-ray imaging of a globular cluster core: Compact binaries in 47Tuc SO SCIENCE LA English DT Article ID HUBBLE-SPACE-TELESCOPE; CATACLYSMIC VARIABLES; MILLISECOND PULSARS; DENSITY PROFILE; 47-TUCANAE; DWARF AB We have obtained high-resolution (less than or similar to1") deep x-ray images of the globular cluster 47Tucanae (NGC 104) with the Chandra X-ray Observatory to study the population of compact binaries in the high stellar density core. A 70-kilosecond exposure of the cluster reveals a centrally concentrated population of faint (L-x similar to 10(30-33) ergs per second) x-ray sources, with at Least 108 Located within the central 2' x 2.5' and greater than or similar to half with L-x less than or similar to 10(30.5) ergs per second. All 15 millisecond pulsars (MSPs) recently Located precisely by radio observations are identified, though 2 are unresolved by Chandra. The x-ray spectral and temporal characteristics, as well as initial optical identifications with the Hubble Space Telescope, suggest that greater than or similar to 50 percent are MSPs, about 30 percent are accreting white dwarfs, about 15 percent are main-sequence binaries in flare outbursts, and only two to three are quiescent Low-mass x-ray binaries containing neutron stars, the conventional progenitors of MSPs. An upper Limit of about 470 times the mass of the sun is derived for the mass of an accreting central black hole in the cluster. These observations provide the first x-ray "color-magnitude" diagram for a globular cluster and census of its compact object and binary population. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Grindlay, JE (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Heinke, Craig/0000-0003-3944-6109 NR 47 TC 168 Z9 168 U1 0 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 22 PY 2001 VL 292 IS 5525 BP 2290 EP 2295 DI 10.1126/science.1061135 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 445KD UT WOS:000169455900046 PM 11358997 ER PT J AU Royer, DL Wing, SL Beerling, DJ Jolley, DW Koch, PL Hickey, LJ Berner, RA AF Royer, DL Wing, SL Beerling, DJ Jolley, DW Koch, PL Hickey, LJ Berner, RA TI Paleobotanical evidence for near present-day levels of atmospheric CO2 during part of the tertiary SO SCIENCE LA English DT Article ID PALEOCENE-EOCENE BOUNDARY; CARBON-DIOXIDE; ICE CORE; CLIMATE; RECORD; MARINE; RESPONSES; LEAVES; END; L. AB Understanding the Link between the greenhouse gas carbon dioxide (CO2) and Earth's temperature underpins much of paleoclimatology and our predictions of future global warming. Here, we use the inverse relationship between Leaf stomatal indices and the partial pressure of CO2 in modern Ginkgo biloba and Metasequoia glyptostroboides to develop a CO2 reconstruction based on fossil Ginkgo and Metaseguoia cuticles for the middle Paleocene to early Eocene and middle Miocene. Our reconstruction indicates that CO2 remained between 300 and 450 parts per million by volume for these intervals with the exception of a single high estimate near the Paleocene/Eocene boundary. These results suggest that factors in addition to CO2 are required to explain these past intervals of global warmth. C1 Yale Univ, Dept Geol & Geophys, New Haven, CT 06520 USA. Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. Univ Sheffield, Dept Anim & Plant Sci, Sheffield S10 2TN, S Yorkshire, England. Univ Sheffield, Ctr Palynol, Sheffield S3 7HF, S Yorkshire, England. Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. RP Royer, DL (reprint author), Yale Univ, Dept Geol & Geophys, POB 208109, New Haven, CT 06520 USA. EM dana.royer@yale.edu RI Beerling, David/C-2840-2009 OI Beerling, David/0000-0003-1869-4314 NR 34 TC 207 Z9 229 U1 8 U2 66 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD JUN 22 PY 2001 VL 292 IS 5525 BP 2310 EP 2313 DI 10.1126/science.292.5525.2310 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 445KD UT WOS:000169455900052 PM 11423657 ER PT J AU Johnson, DG Jucks, KW Traub, WA Chance, KV AF Johnson, DG Jucks, KW Traub, WA Chance, KV TI Isotopic composition of stratospheric water vapor: Measurements and photochemistry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INFRARED SOLAR SPECTRA; TRANSITION FREQUENCIES; PLANETARY-ATMOSPHERES; HYDROGEN BUDGET; METHANE; OZONE; FRACTIONATION; ABUNDANCES; DEUTERIUM; STRENGTHS AB We present a photochemical model describing the changes in the isotopic composition of stratospheric water vapor that result from methane oxidation and reactions with O(D-1). We then compare model calculations with measurements made with the Smithsonian Astrophysical Observatory far-infrared spectrometer during seven balloon flights that took place between 1989 and 1997. The agreement between the model calculations and measurements establishes the validity of the model and the internal consistency of the data set. Finally, we use the model and measurements together to estimate the mixing ratio and isotopic composition of water vapor entering the stratosphere and find that the average over all flights of the water vapor mixing ratio, deltaD, delta O-18, and delta O-17 are 3.48 +/- 0.15 parts per million by volume, -679 +/- 20 parts per thousand, -128 +/- 31 parts per thousand, and -84 +/- 31 parts per thousand, respectively, where the errors indicate the estimated accuracy. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Johnson, DG (reprint author), NASA, Langley Res Ctr, MS 468, Hampton, VA 23681 USA. EM d.g.johnson@larc.nasa.gov; kjucks@cfa.harvard.edu; wtraub@cfa.harvard.edu; kchance@cfa.harvard.edu RI Johnson, David/F-2376-2015; OI Johnson, David/0000-0003-4399-5653; Chance, Kelly/0000-0002-7339-7577 NR 36 TC 32 Z9 32 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 16 PY 2001 VL 106 IS D11 BP 12211 EP 12217 DI 10.1029/2000JD900763 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 442TC UT WOS:000169300200036 ER PT J AU Johnson, DG Jucks, KW Traub, WA Chance, KV AF Johnson, DG Jucks, KW Traub, WA Chance, KV TI Isotopic composition of stratospheric water vapor: Implications for transport SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERE; DEUTERIUM; TROPOPAUSE; PACIFIC AB We develop a series of models of transport in the upper tropical troposphere in order to explain the observed abundance and isotopic composition of stratospheric water vapor. We start with the Rayleigh fractionation process and add the effects of mixing and recirculation of stratospheric air through the upper troposphere. We compare our measurements with model calculations for a range of input parameters and find that the observations are best explained by a model that mixes vapor from roughly 11 km (carried aloft either as condensate or through radiative heating and uplift) with air that has been dehydrated (in a large convective system) to a mixing ratio substantially below the saturation mixing ratio of the mean tropical tropopause. The result is that while most of the moisture comes from convective outflow near ii km, most of the air in the upper troposphere consists of dehydrated air from convective systems with cloud top temperatures below that of the mean tropical tropopause. We also find that the water vapor mixing ratio in the stratosphere is determined not only by the temperature of the tropical tropopause but also by the relative importance of radiative heating, recirculation of stratospheric air, and deep convection in supplying air to the upper troposphere. Our results show that water vapor isotope ratios are a powerful diagnostic tool for testing the results of general circulation models. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Johnson, DG (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. RI Johnson, David/F-2376-2015; OI Johnson, David/0000-0003-4399-5653; Chance, Kelly/0000-0002-7339-7577 NR 21 TC 38 Z9 38 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 16 PY 2001 VL 106 IS D11 BP 12219 EP 12226 DI 10.1029/2000JD900764 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 442TC UT WOS:000169300200037 ER PT J AU Andrews, WR Targett, NM Epifanio, CE AF Andrews, WR Targett, NM Epifanio, CE TI Isolation and characterization of the metamorphic inducer of the common mud crab, Panopeus herbstii SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE metamorphosis; mud crab; recruitment; settlement ID LARVAL SETTLEMENT; RED ALGAE; EURYPANOPEUS-DEPRESSUS; CALLINECTES-SAPIDUS; CHEMICAL CUES; UCA-PUGILATOR; XANTHID CRABS; DELAWARE BAY; HABITAT; MEGALOPAE AB Several items from the natural habitat of adult Panopeus herbstii were examined to determine if they had the ability to produce a metamorphic cue. These included adult conspecifics, natural rock/shell substratum. the co-occurring species Hemigrapsus sanguineus and bacterial biofilms. Adult conspecifics, H. sangineus and natural rock/shell all accelerated metamorphosis. However, adult conspecifics accelerated metamorphosis to the greatest extent. The cue associated with adult conspecifics was found to be water-soluble, stable following boiling and freezing, and of relatively small molecular size (< 1 kDa). Furthermore, the cue appears to be produced from the conspecifics themselves, rather than from biofilms colonizing the surfaces of the crabs. The results of this experiment suggest that postlarvae of P. herbsrii are able to distinguish suitable habitat through chemical signals, thus greatly increasing their chances for survival. (C) 2001 Published by Elsevier Science B.V. C1 Univ Delaware, Coll Marine Studies, Lewes, DE 19958 USA. RP Andrews, WR (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. NR 39 TC 17 Z9 18 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD JUN 15 PY 2001 VL 261 IS 1 BP 121 EP 134 DI 10.1016/S0022-0981(01)00268-4 PG 14 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 441UT UT WOS:000169248500008 ER PT J AU McLaughlin, BM Kirby, KP AF McLaughlin, BM Kirby, KP TI Electron collisional excitation of the 1s(2)2s(2)2p(3) (S-4(3/2)o, D-2(5/2,3/2)o, P-2(3/2,1/2)o) fine-structure levels in Fe19+ ions SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ATOMIC DATA; OPACITY CALCULATIONS; RATE COEFFICIENTS; FE-XIX; PROGRAM; PHOTOIONIZATION; RECOMBINATION; TRANSITIONS AB Collision strengths for electron-impact excitation of nitrogen-like Fe ions (Fe19+) have been calculated within the semi-relativistic R-matrix Breit-Pauli approximation. Twenty-three fine-structure levels arising from the 12 2s(2)2p(3), 2S(2)p(4), 2p(5) and 2s(2)2p(2)3s LS pi target states are included in this paper. Effective collision strengths for all forbidden transitions between the 1s(2)2s(2)2p(3) 4S(3/2)(o), D-2(5/2,3/2)o, P-2(3/2,1/2)o terms are obtained by averaging the electron-collision strengths, for a wide range of incident electron energies, over a Maxwellian distribution of velocities. Results are presented for electron temperatures in the range 5.0 less than or equal to Log T-e less than or equal to 8.0 K, applicable to many astrophysical plasmas. Our effective collision strengths, when compared with published values obtained within the distorted wave approximation, show considerable differences which we attribute to the presence of strong resonance structure in the cross sections. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP McLaughlin, BM (reprint author), Queens Univ Belfast, Dept Appl Math & Theoret Phys, Belfast BT7 1NN, Antrim, North Ireland. NR 31 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUN 14 PY 2001 VL 34 IS 11 BP 2255 EP 2265 DI 10.1088/0953-4075/34/11/317 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 449CA UT WOS:000169665700021 ER PT J AU Wu, KKS Fabian, AC Nulsen, PEG AF Wu, KKS Fabian, AC Nulsen, PEG TI The soft X-ray background: evidence for widespread disruption of the gas haloes of galaxy groups SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : clusters : general; cooling flows; galaxies : haloes; intergalactic medium; X-rays : galaxies ID DEEP ROSAT SURVEY; OPTICAL-IDENTIFICATION; INTRAGROUP MEDIUM; DENSITY PROFILE; COOLING FLOWS; CLUSTERS; EVOLUTION; CONSTRAINTS; FLUCTUATIONS; PREDICTIONS AB Almost all of the extragalactic X-ray background (XRB) at 0.25 keV can be accounted for by radio-quiet quasars, allowing us to derive an upper limit of 4 keV cm(-2) s(-1) sr(-1) keV(-1) for the remaining background at 0.25 keV. However, the XRB from the gas haloes of groups of galaxies, with gas removal resulting from cooling accounted for, exceeds this upper limit by an order of magnitude if non-gravitational heating is not included. We calculate this using simulations of halo merger trees and realistic gas density profiles, which we require to reproduce the observed gas fractions and abundances of X-ray clusters. In addition, we find that the entire mass range of groups, from similar to5 x 10(12) to similar to 10(14) M., contributes to the 0.25-keV background in this case. In a further study, we reduce the luminosities of groups by maximally heating their gas haloes while maintaining the same gas fractions. This reduces the XRB by only a factor of 2 or less. We thus argue that most of the gas associated with groups must be outside their virial radii. This conclusion is supported by X-ray studies of individual groups. The properties of both groups and X-ray clusters can be naturally explained by a model in which the gas is given excess specific energies of similar to1 keV per particle by non-gravitational heating. With this excess energy, the gas is gravitationally unbound from groups, but recollapses with the formation of a cluster of temperature greater than or similar to 1 keV. This is similar to a model proposed by Pen, but is contrary to the evolution of baryons described by Cen & Ostriker. In addition to the soft XRB spectrum, we simulate source counts in two bands, 0.1-0.4 keV and 0.5-2 keV, for comparison with present and future data. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. Univ Wollongong, Dept Engn Phys, Wollongong, NSW 2522, Australia. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Wu, KKS (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. NR 49 TC 38 Z9 38 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUN 11 PY 2001 VL 324 IS 1 BP 95 EP 107 DI 10.1046/j.1365-8711.2001.04216.x PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 443QW UT WOS:000169352700014 ER PT J AU Corbel, S Kaaret, P Jain, RK Bailyn, CD Fender, RP Tomsick, JA Kalemci, E McIntyre, V Campbell-Wilson, D Miller, JM McCollough, ML AF Corbel, S Kaaret, P Jain, RK Bailyn, CD Fender, RP Tomsick, JA Kalemci, E McIntyre, V Campbell-Wilson, D Miller, JM McCollough, ML TI X-ray states and radio emission in the black hole candidate XTE J1550-564 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; radio continuum : stars; stars : individual (XTE J1550-564); X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; GRO J1655-40; OPTICAL OBSERVATIONS; EVOLUTIONARY STATE; TIMING EXPLORER; GX-339-4; JET AB We report on radio and X-ray observations of the black hole candidate (BHC) XTE J1550-564 performed during its 2000 X-ray outburst. Observations were conducted with the Australia Telescope Compact Array and allowed us to sample the radio behavior of XTE J1550-564 in the X-ray low hard and intermediate/very high states. We observed optically thin radio emission from XTE J1550-564 5 days after a transition to an intermediate/very high state, but we observed no radio emission 6 days later, while XTE J1550-564 was still in the intermediate/very high state. In the low hard state, XTE J1550-564 is detected with an inverted radio spectrum. The radio emission in the low hard state most likely originates from a compact jet; optical observations suggest that the synchrotron emission from this jet may extend up to the optical range. The total power of the compact jet might therefore be a significant fraction of the total luminosity of the system. We suggest that the optically thin radio emission detected 5 days after the transition to the intermediate/very high state is due to a discrete ejection of relativistic plasma during the state transition. Subsequent to the decay of the optically thin radio emission associated with the state transition, it seems that in the intermediate/very high state the radio emission is quenched by a factor greater than 50, implying a suppression of the outflow. We discuss the properties of radio emission in the X-ray states of BHCs. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Australia Telescope Natl Facil, Epping, NSW 1710, Australia. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Space Res Assoc, Huntsville, AL 35812 USA. Univ Paris 07, F-91191 Gif Sur Yvette, France. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. RP Corbel, S (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 51 TC 101 Z9 101 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 JUN 10 PY 2001 VL 554 IS 1 BP 43 EP 48 DI 10.1086/321364 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MV UT WOS:000169690800005 ER PT J AU Hu, W White, M AF Hu, W White, M TI Power spectra estimation for weak lensing SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; gravitational lensing; large-scale structure of universe ID LARGE-SCALE STRUCTURE; GALAXY ELLIPTICITIES; DISTANT GALAXIES AB We develop a method for estimating the shear power spectra from weak-lensing observations and test it on simulated data. Our method describes the shear field in terms of angular power spectra and the cross-correlation of the two shear modes, which differ under parity transformations. Two of the three power spectra can be used to monitor unknown sources of noise in the data. The power spectra are decomposed in a model-independent manner in terms of "band powers," which are then extracted from the data using a quadratic estimator to find the maximum of the likelihood and its local curvature (for error estimates). We test the method against simulated data from Gaussian realizations and cosmological N-body simulations. In the Gaussian case, the mean band powers and their covariance are well recovered even for irregular (or sparsely) sampled fields. The mild non-Gaussianity of the N-body realizations causes a slight underestimation of the errors that becomes negligible for scales much larger than several arcminutes and does not bias the recovered band powers. These techniques can also be directly applied to cosmic microwave background polarization E and B mode analyses on small fields. C1 Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Hu, W (reprint author), Univ Chicago, Dept Astron & Astrophys, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI White, Martin/I-3880-2015 OI White, Martin/0000-0001-9912-5070 NR 22 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 JUN 10 PY 2001 VL 554 IS 1 BP 67 EP 73 DI 10.1086/321380 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MV UT WOS:000169690800008 ER PT J AU Arce, HG Goodman, AA AF Arce, HG Goodman, AA TI The episodic, precessing giant molecular outflow from IRAS 04239+2436 (HH 300) SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : Herbig-Haro objects; ISM : individual (B18, HH 300); ISM : jets and outflows; stars : formation ID STAR-FORMATION; CO OUTFLOWS; BIPOLAR OUTFLOWS; DARK CLOUDS; JETS; BULLETS; TAURUS; DRIVEN; FLOWS; EXTINCTION AB We present the first set of detailed molecular-line maps of the region associated with the giant Herbig-Haro flow HH 300 from the young star IRAS 04239 + 2436. Our results indicate that the red lobe of the HH 300 flow is depositing a fair amount of momentum [3.2(sin i)(-1) M-. km s(-1)] and kinetic energy [2.6(sin i)(-2) x 10(43) ergs] over a notable volume (similar to 11%) of its host dark cloud. This makes HH 300 a key player in the evolution and fate of its parent cloud. The redshifted molecular outflow lobe of HH 300 is 1.1 pc long and 0.3 pc wide and has a very clumpy structure. The density, velocity, and momentum distributions in the outflow indicate that the observed clumps arise from the prompt entrainment of ambient gas. Bow shock-shaped structures are associated with the clumps, and we hypothesize that the shocks are produced by different mass ejection episodes. Lines drawn from IRAS 04239 + 2436 to each of these clumps have different orientations on the plane of the sky, and we conclude that HH 300 is a precessing and episodic outflow. The observations include a map of the red lobe in the CO (2-1) line, with a beam size of 27", and more extended maps of the outflow region in the (CO)-C-12 (1-0) and (CO)-C-13 (1-0) lines, with 45" and 47" beam sizes, respectively. Due to "contamination" by emission from another molecular cloud along the same line of sight, we are not able to study the blueshifted lobe of HH 300. The combined (CO)-C-12 (1-0) and (CO)-C-13 (1-0) line observations enable us to estimate the outflow mass accounting for the velocity-dependent opacity of the (CO)-C-12 (1-0) line. This method is much more precise than using (CO)-C-12 data alone. We obtain a steep power-law mass spectrum for HH 300, which we believe is best explained by the evolution of the outflow mass kinematics. In addition, our (CO)-C-13 (1-0) observations show that the HH 300 flow has been able to redistribute tin space and velocity) considerable amounts of its surrounding medium-density (similar to 10(3) cm(-3)) gas. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Arce, HG (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Goodman, Alyssa/A-6007-2010 OI Goodman, Alyssa/0000-0003-1312-0477 NR 50 TC 58 Z9 58 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 JUN 10 PY 2001 VL 554 IS 1 BP 132 EP 151 DI 10.1086/321334 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MV UT WOS:000169690800014 ER PT J AU Churazov, E Bruggen, M Kaiser, CR Bohringer, H Forman, W AF Churazov, E Bruggen, M Kaiser, CR Bohringer, H Forman, W TI Evolution of buoyant bubbles in M87 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cooling flows; galaxies : active; galaxies : clusters : individual (Virgo); galaxies : individual (M87); X-rays : galaxies ID RAY-EMITTING GAS; X-RAY; COOLING FLOWS; MAGNETIC-FIELDS; RADIO-SOURCES; THERMAL-INSTABILITY; VIRGO CLUSTER; ROSAT; NGC-1275; M-87 AB The morphology of the X-ray- and radio-emitting features in the central similar to 50 kpc region around the galaxy M87 strongly suggests that buoyant bubbles of cosmic rays (inflated by an earlier nuclear active phase of the galaxy) rise through the cooling gas at roughly half the sound speed. In the absence of strong surface tension, initially spherical bubbles will transform into tori as they rise through an external medium. Such structures can be identified in the radio images of the halo of M87. During their rise, bubbles will uplift relatively cool X-ray-emitting gas from the central regions of the cooling flow to larger distances. This gas is colder than the ambient gas and has a higher volume emissivity. As a result, rising "radio" bubbles may be trailed by elongated X-ray features, as indeed is observed in M87. We performed simple hydrodynamic simulations to illustrate qualitatively the evolution of buoyant bubbles in the M87 environment. C1 Max Planck Inst Astrophys, D-85740 Garching, Germany. Russian Acad Sci, Space Res Inst IKI, Moscow 117810, Russia. Univ Cambridge Churchhill Coll, Cambridge CB3 0DS, England. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Churazov, E (reprint author), Max Planck Inst Astrophys, Karl Schwarzschild Str 1,Postfach 1523, D-85740 Garching, Germany. RI Churazov, Eugene/A-7783-2013 NR 49 TC 444 Z9 447 U1 1 U2 8 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 JUN 10 PY 2001 VL 554 IS 1 BP 261 EP 273 DI 10.1086/321357 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MV UT WOS:000169690800024 ER PT J AU Still, M O'Brien, K Horne, K Boroson, B Titarchuk, LG Engle, K Vrtilek, SD Quaintrell, H Fiedler, H AF Still, M O'Brien, K Horne, K Boroson, B Titarchuk, LG Engle, K Vrtilek, SD Quaintrell, H Fiedler, H TI Atmospheric reflection during an anomalous low state of Hercules X-l SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; binaries : eclipsing; pulsars : individual (Hercules X-1) radiative transfer; stars : neutron; X-rays : stars ID ABSORPTION CROSS-SECTIONS; ACTIVE GALACTIC NUCLEI; RAY-TIMING-EXPLORER; ACCRETION DISKS; SPECTRA; X-1; RADIATION; BINARIES; BEPPOSAX; LINES AB We present RXTE observations of the eclipsing X-ray binary Hercules X-l during an anomalous low state. Data reduction reveals a light curve over 2.7 orbital cycles remarkably similar to optical and UV light curves dominated by the companion star. Count rates are modulated close to the orbital period, attaining a maximum when the inner face of the companion star, irradiated by X-rays from the compact source, is most visible. Cold reflection provides an acceptable fit to the energy spectrum. Employing binary geometry to scale the model and assuming companion-star reflection, we are able to reconstruct the incident X-rays that are removed from our direct line of sight (presumably by the accretion disk). We find the flux of the hidden source to be identical to the observed flux of Her X-l at the peak of its main high state. Consequently, Her X-l is emitting a reflected spectrum, largely uncontaminated by direct X-rays in the anomalous low state. The spectral energy distribution, period, amplitude, and phasing of the modulation are all consistent with a companion-star origin. Since this source occurs in a well-understood binary environment, it provides an excellent case study for more sensitive experiments in the future. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Open Univ, Dept Phys, Milton Keynes MK7 6AA, Bucks, England. Univ Munich, Inst Astron & Astrophys, D-81679 Munich, Germany. RP Still, M (reprint author), Univ Space Res Assoc, Columbia, MD 21044 USA. NR 42 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 JUN 10 PY 2001 VL 554 IS 1 BP 352 EP 361 DI 10.1086/321337 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MV UT WOS:000169690800032 ER PT J AU Fryer, CL Kalogera, V AF Fryer, CL Kalogera, V TI Theoretical black hole mass distributions SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; black hole physics; stars : evolution; stars : mass loss; stars : neutron; supernovae : general ID X-RAY BINARIES; NOVA SCORPII 1994; NEUTRON-STAR; PRESUPERNOVA EVOLUTION; GRO J1655-40; MAXIMUM MASS; SUPERNOVAE; TRANSIENT; HYDRODYNAMICS; METALLICITY AB We derive the theoretical distribution function of black hole masses by studying the formation processes of black holes. We use the results of recent two-dimensional simulations of stellar core collapse to obtain the relation between remnant and progenitor masses and fold it with an initial mass function for the progenitors. Thus, we are able to derive the binary black hole mass distribution. We examine how the calculated black hole mass distributions are modified by (1) strong-wind mass loss at different evolutionary stages of the progenitors and (2) the presence of close binary companions to the black hole progenitors. The compact-remnant distribution is dominated by neutron stars in the mass range 1.2-1.6 M-. and falls off exponentially at higher remnant masses. Our results are most sensitive to mass loss from stellar winds (particularly from Wolf-Rayet stars), and the effects of winds are even more important in close binaries. Wind mass loss leads to flatter black hole mass distributions and limits the maximum possible black hole mass (less than or similar to 10-15 M-.). We also study the effects of the uncertainties in the explosion and unbinding energies for different progenitors. The distributions are continuous and extend over a broad range. We find no evidence for a gap at low values (3-5 M-.) or for a peak at higher values (similar to7 M-.) of black hole masses, but we argue that our black hole mass distribution for binaries is consistent with the current sample of measured black hole masses in X-ray transients. We discuss possible biases against the detection or formation of X-ray transients with low-mass black holes. We also comment on the possibility of black hole kicks and their effect on binaries. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. EM cfryer@ucolick.org; vkalogera@cfa.harvard.edu NR 49 TC 288 Z9 290 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 JUN 10 PY 2001 VL 554 IS 1 BP 548 EP 560 DI 10.1086/321359 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MV UT WOS:000169690800050 ER PT J AU Bjorkman, JE Wood, K AF Bjorkman, JE Wood, K TI Radiative equilibrium and temperature correction in Monte Carlo radiation transfer SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; radiative transfer; scattering ID AXISYMMETRICAL DUST CLOUDS; YOUNG STELLAR OBJECTS; SCATTERING ENVELOPES; CIRCUMSTELLAR DISKS; INFRARED-EMISSION; MOLECULAR CLOUDS; POLARIZATION; PROTOSTARS; REGIONS; GRAINS AB We describe a general radiative equilibrium and temperature correction procedure for use in Monte Carlo radiation transfer codes with sources of temperature-independent opacity, such as astrophysical dust. The technique utilizes the fact that Monte Carlo simulations track individual photon packets, so we may easily determine where their energy is absorbed. When a packet is absorbed, it heats a particular cell within the envelope, raising its temperature. To enforce radiative equilibrium, the absorbed packet is immediately reemitted. To correct the cell temperature, the frequency of the reemitted packet is chosen so that it corrects the temperature of the spectrum previously emitted by the cell. The reemitted packet then continues being scattered, absorbed, and reemitted until it finally escapes from the envelope. As the simulation runs, the envelope heats up, and the emergent spectral energy distribution (SED) relaxes to its equilibrium value without iteration. This implies that the equilibrium temperature calculation requires no more computation time than the SED calculation of an equivalent pure scattering model with fixed temperature. In addition to avoiding iteration, our method conserves energy exactly because all injected photon packets eventually escape. Furthermore, individual packets transport energy across the entire system because they are never destroyed. This long-range communication, coupled with the lack of iteration, implies that our method does not suffer the convergence problems commonly associated with Lambda -iteration. To verify our temperature correction procedure, we compare our results with standard benchmark tests, and finally we present the results of simulations for two-dimensional axisymmetric density structures. C1 Univ Toledo, Dept Phys & Astron, Ritter Observ, Toledo, OH 43606 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Bjorkman, JE (reprint author), Univ Toledo, Dept Phys & Astron, Ritter Observ, Toledo, OH 43606 USA. NR 26 TC 207 Z9 207 U1 1 U2 12 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 JUN 10 PY 2001 VL 554 IS 1 BP 615 EP 623 DI 10.1086/321336 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MV UT WOS:000169690800057 ER PT J AU Abramowicz, MA Igumenshchev, IV AF Abramowicz, MA Igumenshchev, IV TI How dim could accreting black holes be? SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; convection ID ADVECTION-DOMINATED ACCRETION; FLOWS; CONVECTION; TRANSIENTS; QUIESCENCE; TURBULENCE; OUTFLOWS; DISKS; MODEL AB Recent hydrodynamical simulations of radiatively inefficient black hole accretion flows with low viscosity have demonstrated that these flows differ significantly from those described by an advection-dominated model. The black hole flows are advection-dominated only in their inner parts but convectively dominated at radii R greater than or similar to 10(2)R(G). In such flows, the radiative output comes mostly from the convection part, and the radiative efficiency is independent of accretion rate and equals epsilon (BH) = 10(-3). This value gives a limit for how dim an accreting black hole could be. It agrees with recent Chandra observations, which indicate that accreting black holes in low-mass X-ray binaries are dimmer by a factor of about 100 than neutron stars accreting with the same accretion rates. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Abramowicz, MA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 28 TC 8 Z9 8 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 JUN 10 PY 2001 VL 554 IS 1 BP L53 EP L54 DI 10.1086/320933 PN 2 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MW UT WOS:000169690900013 ER PT J AU Bourke, TL AF Bourke, TL TI IRAS 11590-6452 in BHR 71: A binary protostellar system? SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; ISM : globules; ISM : individual (BHR 71); ISM : jets and outflows; stars : formation; stars : pre-main-sequence ID SMALL DARK CLOUDS; STAR-FORMATION; OUTFLOW AB New Angle-Australian Telescope near-infrared and Swedish-ESO Submillimetre Telescope (CO)-C-12 J = 2 --> 1 observations are combined with existing Infrared Space Observatory mid-infrared and Australia Telescope Compact Array centimeter radio continuum observations to examine the protostellar content of the Bok globule BHR 71. Together with observations of Herbig-Haro objects, these data show the following: (1) Two protostellar sources, IRS 1 and IRS 2, with a separation of similar to 17" (3400 AU) are located within BHR 71. (2) Each protostar is driving its own molecular outflow. The outflow from IRS 1 is much larger in extent, is more massive, and dominates the CO emission. (3) Both protostars are associated with Herbig-Haro objects and shock-excited 2.122 mum H-2 upsilon = 1-0 S(1) emission, which coincide spatially with their CO outflows. (4) IRS 1 is associated with centimeter continuum emission, with a flat or rising spectrum, which is consistent with free-free emission, a signpost of protostellar origin. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Bourke, TL (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 42, Cambridge, MA 02138 USA. NR 10 TC 24 Z9 24 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 JUN 10 PY 2001 VL 554 IS 1 BP L91 EP L94 DI 10.1086/320921 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MW UT WOS:000169690900022 ER PT J AU Feldman, PD Ake, TB Berman, AF Moos, HW Sahnow, DJ Strobel, DF Weaver, HA Young, PR AF Feldman, PD Ake, TB Berman, AF Moos, HW Sahnow, DJ Strobel, DF Weaver, HA Young, PR TI Detection of chlorine ions in the Far Ultraviolet Spectroscopic Explorer spectrum of the Io plasma torus SO ASTROPHYSICAL JOURNAL LA English DT Article DE planets and satellites : individual (Io, Jupiter); ultraviolet : solar system ID ELECTRON COLLISION EXCITATION; SINGLY IONIZED SULFUR; FINE-STRUCTURE LEVELS; S-II; STRENGTHS; TELESCOPE; JUPITER AB The spectrum of the Io plasma torus in the range of 995-1187 Angstrom was recorded at 0.26 Angstrom resolution by the Far Ultraviolet Spectroscopic Explorer (FUSE) on 2000 January 20. Five orbits of data were obtained in point-and-shoot mode (no tracking of the moving target), with the east ansa of the torus initially centered in the 30 " x 30 " aperture of the FUSE LiF spectrographs yielding a total observation time of 3405 s. The spectral resolution exceeds by a factor of 10 that of the data obtained by the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 mission. This region of the spectrum is dominated by resonance multiplets of S III and S IV, whose multiplet structures are nearly completely resolved, as well as numerous S II multiplets originating on the D-2(o) state of the ground configuration. Weak emission from a few lines of the resonance multiplets of Cl III and Cl II is detected at or above the 3 sigma level, Cl III being stronger with two components roughly one-tenth the brightness of the main components of S III lambda 1018. We derive an abundance of Cl+2 of 3% relative to S+2, leading to an overall chlorine ion abundance in the torus of approximate to1%. The ratio of S IV to S III brightness is about twice that observed by HUT, which, when the different slit geometries are accounted for, supports the earlier analysis that S IV emissions originate from a region more extended out of the centrifugal plane than the S III emissions. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Feldman, PD (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Charles & 34th St,Bloomberg Ctr, Baltimore, MD 21218 USA. RI Weaver, Harold/D-9188-2016 NR 22 TC 28 Z9 28 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2001 VL 554 IS 1 BP L123 EP L126 DI 10.1086/320920 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MW UT WOS:000169690900030 ER PT J AU Kharchenko, V Dalgarno, A AF Kharchenko, V Dalgarno, A TI Variability of cometary X-ray emission induced by solar wind ions SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; comets : general; X-rays : general ID SELECTIVE ELECTRON-CAPTURE; EXTREME-ULTRAVIOLET EMISSION; HALE-BOPP; CHARGE-EXCHANGE; C/1995 O1; COLLISIONS; STATE; HYAKUTAKE; SPECTRA; SPECTROSCOPY AB X-ray emission spectra induced by the interaction of the slow and fast solar wind components with cometary gas are calculated for typical solar wind compositions. The emission spectra arising from the charge transfer mechanism are shown to be in good agreement with observational data. The identities and intensities of the brightest spectral lines that include forbidden transitions are obtained for the slow and fast solar winds. Differences in emission spectra of individual comets occur because of variations in the solar wind composition. Comparisons with observational data for comets Levy and Hale-Bopp indicate that they were subjected to the slow solar wind. The spectra at photon energies above 500 eV fluctuate with the solar wind composition because of the varying presence of fully stripped oxygen ions. Mechanisms of X-ray photon emission at energies above 0.9 keV are discussed. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kharchenko, V (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 37 TC 69 Z9 69 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2001 VL 554 IS 1 BP L99 EP L102 DI 10.1086/320929 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MW UT WOS:000169690900024 ER PT J AU Menou, K Perna, R Hernquist, L AF Menou, K Perna, R Hernquist, L TI Disk-assisted spin-down of young radio pulsars SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; pulsars : general; stars : neutron; supernovae : general ID X-RAY LUMINOSITY; NEUTRON-STARS; BLACK-HOLE; RADIATION AB We present a model for the spin-down of young radio pulsars in which the neutron star loses rotational energy not only by emitting magnetic dipole radiation but also by torquing a surrounding disk produced by supernova fallback. The braking index predicted in our model is, in general, less than n = 3 (the value for pure magnetic dipole radiation), in agreement with the reported values of n < 3 for five young radio pulsars. With an accuracy of 30% or better, our model reproduces the age, braking index, and third-frequency derivative of the Crab pulsar for a disk mass inflow rate in the range of 3 x 10(16)-10(17) g s(-1). C1 Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Menou, K (reprint author), Princeton Univ, Dept Astrophys Sci, Peyton Hall,Ivy Lane, Princeton, NJ 08544 USA. NR 42 TC 51 Z9 53 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 JUN 10 PY 2001 VL 554 IS 1 BP L63 EP L66 DI 10.1086/320927 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MW UT WOS:000169690900016 ER PT J AU Warren, HP Reeves, KK AF Warren, HP Reeves, KK TI High spatial resolution observations of a hot region in a solar flare with the transition region and coronal explorer SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : flares ID ABSOLUTE ABUNDANCE; TEMPERATURE; PLASMA; RECONNECTION; MORPHOLOGY; TELESCOPE; CALCIUM; LOOPS; TRACE; IRON AB The Transition Region and Coronal Explorer (TRACE) provides some of the highest spatial resolution images ever taken of hot solar flare plasma. The TRACE 195 Angstrom channel is particularly sensitive to high-temperature Rare plasma because of the presence of the Fe XXIV lambda 192 resonance line in this bandpass. The TRACE 171 Angstrom channel observes emission From thermal bremsstrahlung during a flare. Since this emission is generally weak, it is usually not possible to derive electron temperatures for flare plasma from TRACE observations. In this Letter, we present analysis of the 2000 March 24 X1.8 limb flare that produced high count rates in both the TRACE 195 and 171 Angstrom channels. We find evidence for a small, high-temperature region near the top of the Rare arcade. This hot region appears to lie at the base of the cusp-shaped structure that extends above the arcade. The TRACE observations are consistent with a strong enrichment of Fe over its photospheric value in the hot region that suggests in situ heating of this plasma. We also find that multithermal simulations of Rare evolution reproduce the observations much better than an isothermal model does. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Warren, HP (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 58, Cambridge, MA 02138 USA. RI Reeves, Katharine/P-9163-2014 NR 24 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 JUN 10 PY 2001 VL 554 IS 1 BP L103 EP L106 DI 10.1086/320919 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449MW UT WOS:000169690900025 ER PT J AU Romanowsky, AJ Kochanek, CS AF Romanowsky, AJ Kochanek, CS TI Dynamics of stars and globular clusters in M87 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : elliptical and lenticular, cD; galaxies : halos; galaxies : individual (M87); galaxies : kinematics and dynamics; galaxies : star clusters; galaxies : structure; globular clusters : general ID MASSIVE BLACK-HOLE; EARLY-TYPE GALAXIES; ELLIPTIC GALAXIES; SPHERICAL GALAXIES; DARK-MATTER; VELOCITY DISPERSIONS; COLOR DISTRIBUTIONS; SURFACE PHOTOMETRY; PLANETARY-NEBULAE; VIRGO CLUSTER AB We examine the dynamics of the stars and globular clusters in the nearby giant elliptical galaxy M87 and constrain the mass distribution, using all the available data over a large range of radii, including higher order moments of the stellar line-of-sight velocity distributions and the discrete velocities of over 200 globular clusters. We introduce an extension of spherical orbit modeling methods that makes full use of all the information in the data and provides very robust constraints on the mass models. We conclusively rule out a constant mass-to-light ratio model and infer that the radial density profile of the galaxy's dark halo falls off more slowly than r(-2), suggesting that the potential of the Virgo Cluster is already dominant at r similar to 300" similar to 20 kpc. C1 Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Groningen, Kapteyn Astron Inst, Postbus 800, NL-9700 AV Groningen, Netherlands. EM romanow@astro.rug.nl; ckochanek@cfa.harvard.edu NR 84 TC 81 Z9 81 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 JUN 8 PY 2001 VL 553 IS 2 BP 722 EP 732 DI 10.1086/320947 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YX UT WOS:000169429100022 ER PT J AU Adams, FC Myers, PC AF Adams, FC Myers, PC TI Modes of multiple star formation SO ASTROPHYSICAL JOURNAL LA English DT Article DE open clusters and associations : general; stars : formation ID STELLAR MASS-SPECTRUM; OPEN CLUSTER SYSTEM; SOLAR-SYSTEM; DYNAMICAL EVOLUTION; GALACTIC CLUSTERS; MOLECULAR CLOUDS; CONSTRAINTS; ENCOUNTERS; REGIONS; DISKS AB This paper argues that star-forming environments should be classified into finer divisions than the traditional isolated and clustered modes. Using the observed set of Galactic open clusters and theoretical considerations regarding cluster formation, we estimate the fraction of star formation that takes place within clusters. We find that less than similar to 10% of the stellar population originates from star-forming regions destined to become open clusters, confirming earlier estimates. The smallest clusters included in the observational surveys (having at least N similar to 100 members) roughly coincide with the smallest stellar systems that are expected to evolve as clusters in a dynamical sense. We show that stellar systems with too few members N < N-* have dynamical relaxation times that are shorter than their formation can be (1-2 Myr), where the critical number of stars N-* approximate to 100. Our results suggest that star formation can be characterized by (at least) three principal modes: (I) isolated singles and binaries, (II) groups (N < N-*), and (III) clusters (N >N-*). Many-if not most-stars form through the intermediate mode in stellar groups with 10 < N < 100. Such groups evolve and disperse much more rapidly than do open clusters; groups also have a low probability of containing massive stars and are unaffected by supernovae and intense ultraviolet radiation fields. Because of their short lifetimes and small stellar membership, groups have relatively little effect on the star formation process (on average) compared to larger open clusters. C1 Univ Michigan, Michigan Ctr Theoret Phys, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Michigan, Michigan Ctr Theoret Phys, Ann Arbor, MI 48109 USA. EM fca@umich.edu; pmyers@cfa.harvard.edu NR 57 TC 107 Z9 107 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 JUN 8 PY 2001 VL 553 IS 2 BP 744 EP 753 DI 10.1086/320941 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YX UT WOS:000169429100024 ER PT J AU Still, M O'Brien, K Horne, K Hudson, D Boroson, B Vrtilek, SD Quaintrell, H Fiedler, H AF Still, M O'Brien, K Horne, K Hudson, D Boroson, B Vrtilek, SD Quaintrell, H Fiedler, H TI RXTE observations of Hercules X-1 during the 1998 July short high state SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; binaries : eclipsing; stars : individual (Hercules X-1); stars : neutron; X-rays : stars ID RAY-TIMING-EXPLORER; ALL-SKY MONITOR; NEUTRON-STAR; PRE-ECLIPSE; ACCRETION; DIPS; MASS; BEPPOSAX; UHURU; DISCS AB We present RXTE monitoring of the eclipsing X-ray binary Hercules X-1 conducted over the short high state of 1998 July. This was one of the last major short high states before the source entered an anomalous low state of activity. A comparison with previous epochs Dnds no evidence for special behavior during these observations. We determine orbital and pulsar spin periods to facilitate measurements of (P)over dot(spin) and (P)over dot(orb) during the subsequent anomalous low state and the next epoch of high-state activity. Spectrally, the decay of the short high state and concurrent pre-eclipse dips are consistent with obscuration of a central X-ray source by a cloud of nonuniform column density. The standard model of a warped accretion disk of finite vertical scale height fits the characteristics of this absorber well. Pre-eclipse dips have durations a factor of a few longer than the characteristic durations of dips during main high states. Pulse profile structure increases in complexity toward the tail of the short high state, suggesting changes in accretion curtain geometry. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Univ Texas, Dept Astron, Austin, TX 78712 USA. Harvard Smithsonian Ctr Astrophys, High Energy Astrophys Div, Cambridge, MA 02138 USA. Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England. Univ Munich, Inst Astron & Astrophys, D-81679 Munich, Germany. RP Still, M (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 42 TC 11 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 JUN 8 PY 2001 VL 553 IS 2 BP 776 EP 787 DI 10.1086/320951 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YX UT WOS:000169429100027 ER PT J AU Perna, R Heyl, J Hernquist, L AF Perna, R Heyl, J Hernquist, L TI X-ray emission from middle-aged pulsars SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; stars : neutron; X-rays : stars ID NEUTRON-STAR ATMOSPHERES; SURFACE-TEMPERATURE; PSR 0656+14; ROSAT DATA; GEMINGA; RADIATION; MODELS; FIELDS AB We present a simple unified model that accounts for properties of X-ray emission from the three middle-aged pulsars PSR 1055-52, PSR 0656-14, and PSR 0630+18 (Geminga). The X-ray radiation from these objects is pulsed more strongly at energies above a transition point around 0.5 keV. In addition, the phase of the pulses shifts by about 80 degrees -100 degrees around the same point. Geminga also has the peculiarity that its pulsed fraction decreases in the 0.3-0.5 keV energy range, attaining a minimum near 0.5 keV. We show that a two-component hydrogen atmosphere is able to account for these disparate features. In our model, the hotter component is powered by particle bombardment and is restricted to the polar regions, while the cooler one covers the entire stellar surface. The two components also differ in their emission patterns, with the hard and soft contributions coming from areas radiating into fan and pencil beams, respectively. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 30 TC 5 Z9 5 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 JUN 8 PY 2001 VL 553 IS 2 BP 809 EP 813 DI 10.1086/320985 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YX UT WOS:000169429100031 ER PT J AU Seward, FD Butt, YM Karovska, M Prestwich, A Schlegel, EM Corcoran, M AF Seward, FD Butt, YM Karovska, M Prestwich, A Schlegel, EM Corcoran, M TI Early Chandra X-ray observations of eta Carinae SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : early-type; stars : individual (eta Carinae); X-rays : stars ID VARIABLES; SPECTRUM AB Subarcsecond-resolution Chandra observations of eta Carinae reveal a 40" x 70" ring or partial shell of X-ray emission surrounding an unresolved bright central source. The spectrum of the central source is strongly absorbed and can be fitted with a high-temperature thermal continuum and emission lines. The surrounding shell is well outside the optical/infrared bipolar nebula and is coincident with the outer shell of eta Car. The X-ray spectrum of the shell is much softer than that of the central source. The X-ray shell is irregular and only correlates well with optical features in which a bright X-ray knot coincides with a bright feature of the outer shell. Implications for the binary model of the central source are discussed. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Seward, FD (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. NR 25 TC 36 Z9 36 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 JUN 8 PY 2001 VL 553 IS 2 BP 832 EP 836 DI 10.1086/320961 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YX UT WOS:000169429100034 ER PT J AU Akmal, A Raymond, JC Vourlidas, A Thompson, B Ciaravella, A Ko, YK Uzzo, M Wu, R AF Akmal, A Raymond, JC Vourlidas, A Thompson, B Ciaravella, A Ko, YK Uzzo, M Wu, R TI SOHO observations of a coronal mass ejection SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : activity; Sun : Corona; Sun : coronal mass ejections (CMEs) ID BE-LIKE IONS; COLLISION STRENGTHS; SOLAR; SPECTROMETER; PROMINENCE; EMISSION; ANGSTROM; LASCO; SUN AB We describe a coronal mass ejection (CME) observed on 1999 April 23 by the Ultraviolet Coronagraph Spectrometer (UVCS), the Extreme-Ultraviolet Imaging Telescope (EIT), and the Large-Angle and Spectrometric Coronagraphs (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). In addition to the O VI and C III lines typical of UVCS spectra of CMEs, this 480 km s(-1) CME exhibits the forbidden and intercombination lines of O V at lambda lambda 1213.8 and 1218.4. The relative intensities of the O V lines represent an accurate electron density diagnostic not generally available at 3.5 R-.. By combining the density with the column density derived from LASCO, we obtain the emission measure of the ejected gas. With the help of models of the temperature and time-dependent ionization state of the expanding gas, we determine a range of heating rates required to account for the UV emission lines. The total thermal energy deposited as the gas travels to 3.5 R-. is comparable to the kinetic and gravitational potential energies. We note a core of colder material radiating in C III, surrounded by hotter material radiating in the O V and O VI lines. This concentration of the coolest material into small regions may be a common feature of CMEs. This event thus represents a unique opportunity to describe the morphology of a CME, and to characterize its plasma parameters. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. USN, Res Lab, Washington, DC 20375 USA. George Mason Univ, Inst Computat Sci, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Akmal, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Vourlidas, Angelos/C-8231-2009; Thompson, Barbara/C-9429-2012 OI Vourlidas, Angelos/0000-0002-8164-5948; NR 34 TC 63 Z9 66 U1 1 U2 7 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 JUN 8 PY 2001 VL 553 IS 2 BP 922 EP 934 DI 10.1086/320971 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YX UT WOS:000169429100040 ER PT J AU Wiedner, MC Hills, RE Carlstrom, JE Lay, OP AF Wiedner, MC Hills, RE Carlstrom, JE Lay, OP TI Interferometric phase correction using 183 GHz water vapor monitors SO ASTROPHYSICAL JOURNAL LA English DT Article DE atmospheric effects; instrumentation : adaptive optics; site testing; techniques : interferometric ID PATH-LENGTH; RADIOMETRY; FLUCTUATIONS; ARRAY AB The angular resolution that can be obtained by ground-based aperture synthesis telescopes at millimeter and submillimeter wavelengths is limited by phase fluctuations caused by water vapor in the Earth's atmosphere. We describe here the successful correction of such fluctuations during observations at 0.85 mm wavelength with an interferometer consisting of the James Clark Maxwell Telescope and the Caltech Submillimeter Observatory. This was achieved by using two 183 GHz heterodyne radiometers to measure the water vapor content along the line of sight of each telescope. Further development of such techniques will enable future telescopes, such as the Submillimeter Array and the Atacama Large Millimeter Array, to reach their full capability, providing a resolution of up to 0."01. C1 Univ Cambridge, Cavendish Lab, Mullard Radio Astron Observ, Cambridge CB3 0HE, England. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wiedner, MC (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 30 TC 32 Z9 32 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 JUN 8 PY 2001 VL 553 IS 2 BP 1036 EP 1041 DI 10.1086/320943 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YX UT WOS:000169429100052 ER PT J AU Gioia, IM Henry, JP Mullis, CR Voges, W Briel, UG Bohringer, H Huchra, JP AF Gioia, IM Henry, JP Mullis, CR Voges, W Briel, UG Bohringer, H Huchra, JP TI Cluster evolution in the ROSAT north ecliptic pole survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; surveys; X rays : galaxies; X rays : general ID MEDIUM-SENSITIVITY SURVEY; RAY LUMINOSITY FUNCTION; RICH CLUSTERS; GALAXIES; SAMPLE AB The deepest region of the ROSAT All-Sky Survey, at the north ecliptic pole, has been studied to produce a complete and unbiased X-ray-selected sample of clusters of galaxies. This sample is used to investigate the nature of cluster evolution and to explore the potential implications for large-scale structure models. The survey is 99.6% optically identified. Spectroscopic redshifts have been measured for all the extragalactic identifications. In this Letter, first results on cluster evolution are presented based on a comparison between the number of the observed clusters in the north ecliptic pole survey and the number of expected clusters assuming no-evolution models. At z > 0.3, there is a deficit of clusters with respect to the local universe that is significant at greater than 4.7 sigma. The evolution appears to commence at L0.5-2.0 keV > 1.8 x 10(44) ergs s(-1) in our data. The negative evolution goes in the same direction as the original Extended Medium-Sensitivity Survey result, the results from the 160 deg(2) survey, and the recent results from the ROSAT Deep Cluster Survey. At lower redshifts, there is no evidence for evolution, a result in agreement with these and other cluster surveys. C1 Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Gioia, IM (reprint author), CNR, Ist Radioastron, Via Gobetti 101, I-40129 Bologna, Italy. RI Gioia, Isabella/B-6982-2012 OI Gioia, Isabella/0000-0003-3127-498X NR 38 TC 35 Z9 35 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 8 PY 2001 VL 553 IS 2 BP L105 EP L108 DI 10.1086/320671 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YY UT WOS:000169430800004 ER PT J AU Haisch, KE Lada, EA Lada, CJ AF Haisch, KE Lada, EA Lada, CJ TI Disk frequencies and lifetimes in young clusters SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; open clusters and associations : general; planetary systems : protoplanetary disks; stars : formation ID MAIN-SEQUENCE STARS; CIRCUMSTELLAR DISKS; TRAPEZIUM CLUSTER; PLANET FORMATION; MOLECULAR CLOUD; SOLAR NEBULA; EVOLUTION; PHOTOMETRY; IC-348; FIELD AB We report the results of the first sensitive L-band survey of the intermediate-age (2.5-30 Myr) clusters NGC 2264, NGC 2362, and NGC 1960. We use JHKL colors to obtain a census of the circumstellar disk fractions in each cluster. We find disk fractions of,, and for the three clusters, respectively. 52% +/- 10% 12% +/- 4% 3% +/- 3% Together with our previously published JHKL investigations of the younger NGC 2024, Trapezium, and IC 348 clusters, we have completed the first systematic and homogeneous survey for circumstellar disks in a sample of young clusters that both span a significant range in age (0.3-30 Myr) and contain statistically significant numbers of stars whose masses span nearly the entire stellar mass spectrum. Analysis of the combined survey indicates that the cluster disk fraction is initially very high (greater than or equal to 80%) and rapidly decreases with increasing cluster age, such that one-half the stars within the clusters lose their disks in less than or similar to3 Myr. Moreover, these observations yield an overall disk lifetime of similar to6 Myr in the surveyed cluster sample. This is the timescale for essentially all the stars in a cluster to lose their disks. This should set a meaningful constraint for the planet-building timescale in stellar clusters. The implications of these results for current theories of planet formation are briefly discussed. C1 Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Haisch, KE (reprint author), NASA, Ames Res Ctr, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 37 TC 672 Z9 676 U1 2 U2 12 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 JUN 8 PY 2001 VL 553 IS 2 BP L153 EP L156 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YY UT WOS:000169430800015 ER PT J AU Henry, JP Gioia, IM Mullis, CR Voges, W Briel, UG Bohringer, H Huchra, JP AF Henry, JP Gioia, IM Mullis, CR Voges, W Briel, UG Bohringer, H Huchra, JP TI Overview of the ROSAT north ecliptic pole survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE catalogs; surveys; X rays : general ID MEDIUM-SENSITIVITY SURVEY; X-RAY SOURCES; SOURCE CATALOG; STANDARD STARS; CLUSTER; SAMPLE; EVOLUTION; DISCOVERY; GALAXIES; REDSHIFT AB We have used the ROSAT All-Sky Survey (RASS) observations at the north ecliptic pole (NEP) to construct a catalog of X-ray-emitting objects that is both deep and contiguous. We give here an overview of this NEP Survey. Our catalog fully exploits the capabilities of the RASS since the only criterion for inclusion is the source significance and location on the sky. There are 445 unique sources above a flux of similar to2 x 10(-14) ergs s(-1) cm(-2) (0.5- 2. 0 keV) in the 80.7 deg(2) region that we consider. We have optically identified 99.6% of these sources and have obtained redshifts for the extragalactic objects. The main constituents of the catalog are active galactic nuclei (AGNs; 49.0%), stars (34.3%), and groups and clusters of galaxies (14.4%). We provide the NEP Survey selection function (solid angle searched above a given flux limit), the AGNs, the clusters of galaxies, and the BL Lacertae X-ray log N(>S)-log S distribution as well as the catalog redshift distributions for AGNs and clusters. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP CNR, Ist Radioastron, Via Gobetti 101, I-40129 Bologna, Italy. RI Gioia, Isabella/B-6982-2012 OI Gioia, Isabella/0000-0003-3127-498X NR 33 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 EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUN 8 PY 2001 VL 553 IS 2 BP L109 EP L113 DI 10.1086/320672 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YY UT WOS:000169430800005 ER PT J AU Mullis, CR Henry, JP Gioia, IM Bohringer, H Briel, UG Voges, W Huchra, JP AF Mullis, CR Henry, JP Gioia, IM Bohringer, H Briel, UG Voges, W Huchra, JP TI The north ecliptic pole supercluster SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : clusters : general; large scale structure of universe; X rays : general ID GALAXY CLUSTERS; REDSHIFT SURVEY; UNIVERSE; EVOLUTION; FILAMENTS; CATALOG; SCALE AB We have used the ROSAT All-Sky Survey to detect a known supercluster at z = 0.087 in the north ecliptic pole region. The X-ray data greatly improve our understanding of this supercluster's characteristics, approximately doubling our knowledge of the structure's spatial extent and tripling the cluster/group membership compared with the optical discovery data. The supercluster is a rich structure consisting of at least 21 galaxy clusters and groups, 12 active galactic nuclei, 61 IRAS galaxies, and various other objects. A majority of these components were discovered with the X-ray data, but the supercluster is also robustly detected in optical, IR, and UV wave bands. Extending 129 x 102 x 67 (h(50)(-1) Mpc)(3), the north ecliptic pole supercluster has a flattened shape oriented nearly edge-on to our line of sight. Owing to the softness of the ROSAT X-ray passband and the deep exposure over a large solid angle, we have detected for the first time a significant population of X-ray-emitting galaxy groups in a supercluster. These results demonstrate the effectiveness of X-ray observations with contiguous coverage for studying structure in the universe. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CNR, Ist Radioastron, I-40129 Bologna, Italy. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mullis, CR (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. RI Gioia, Isabella/B-6982-2012 OI Gioia, Isabella/0000-0003-3127-498X NR 29 TC 29 Z9 29 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 JUN 8 PY 2001 VL 553 IS 2 BP L115 EP L118 DI 10.1086/320670 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YY UT WOS:000169430800006 ER PT J AU Taylor, JM Grindlay, JE Edmonds, PD Cool, AM AF Taylor, JM Grindlay, JE Edmonds, PD Cool, AM TI Helium white dwarfs and by draconis binaries in the globular cluster NGC 6397 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; binaries : eclipsing; globular clusters : general; globular clusters : individual (NGC 6397); stars : individual (BY Draconis); stars : neutron; stars : rotation; stellar dynamics; white dwarfs ID SHORT-PERIOD BINARY; X-RAY SOURCES; CATACLYSMIC VARIABLES; MILLISECOND PULSARS; TIME-SERIES; NGC-6397; PHOTOMETRY; NGC-6752; EMISSION; STARS AB We examine 15 orbits of Hubble Space Telescope observations of the nearby post-core-collapsed globular cluster NGC 6397 using narrowband photometry in H alpha with broadband photometry in V, R, and I. We recover the candidate helium white dwarfs (He WDs) recently discovered by Cool et al., of which one was examined spectroscopically by Edmonds et al., along with a sequence of these objects extending down to the magnitude limit of the survey. We also find a sequence of stars with weak H alpha emission and magnitudes characteristic of BY Draconis stars; their offset above the main sequence also suggests they are probable binaries. The radial distributions for both the He WD and BY Dra candidates are significantly more centrally concentrated than the main-sequence stars, suggesting that indeed both populations are in binary systems. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94132 USA. RP Taylor, JM (reprint author), Univ Tokyo, Dept Astron, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan. RI Taylor, Jacob/B-7826-2011 OI Taylor, Jacob/0000-0003-0493-5594 NR 30 TC 31 Z9 31 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 8 PY 2001 VL 553 IS 2 BP L169 EP L172 DI 10.1086/320676 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YY UT WOS:000169430800019 ER PT J AU Voges, W Henry, JP Briel, UG Bohringer, H Mullis, CR Gioia, IM Huchra, JP AF Voges, W Henry, JP Briel, UG Bohringer, H Mullis, CR Gioia, IM Huchra, JP TI The ROSAT north ecliptic pole survey X-ray data SO ASTROPHYSICAL JOURNAL LA English DT Article DE catalogs; surveys; X rays : general ID CLUSTERS; GALAXIES AB In the ROSAT All-Sky Survey, an 80.7 deg(2) region near the north ecliptic pole (NEP) constitutes the deepest contiguous observation of the X-ray sky. Four hundred and forty-five unique sources have been detected above a flux of similar to2 x 10(-14) ergs s(-1) cm(-2) (0.5- 2.0 keV). The X-ray data for each source provide a likelihood of existence, position and position error, count rate and error, background count rate at the source position, exposure time, two hardness ratios and their errors, and a measure of extent and likelihood of nonzero extent. We describe the range and statistics of X-ray properties exhibited by the NEP sources and the accuracy with which they have been determined, concentrating on the flux measurement of extended galaxy cluster X-ray sources. We show two examples of sources whose X-ray morphology is useful in their optical identification. C1 Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CNR, Ist Radioastron, I-40129 Bologna, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Voges, W (reprint author), Max Planck Inst Extraterr Phys, Giessenbachstr Postfach 1603, D-85741 Garching, Germany. RI Gioia, Isabella/B-6982-2012 OI Gioia, Isabella/0000-0003-3127-498X NR 19 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 JUN 8 PY 2001 VL 553 IS 2 BP L119 EP L123 DI 10.1086/320673 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444YY UT WOS:000169430800007 ER PT J AU Arnoldi, MJ Kreamer, CM Mason, MA AF Arnoldi, MJ Kreamer, CM Mason, MA TI Reflections on 'African Voices' at the Smithsonian's National Museum of Natural History, December, 1999 SO AFRICAN ARTS LA English DT Art Exhibit Review C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Anthropol, Washington, DC 20560 USA. RP Arnoldi, MJ (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Anthropol, Washington, DC 20560 USA. NR 1 TC 3 Z9 3 U1 0 U2 1 PU UNIV CALIF PI LOS ANGELES PA AFRICAN STUDIES CNTR, LOS ANGELES, CA 90024 USA SN 0001-9933 J9 AFR ARTS JI Afr. Arts PD SUM PY 2001 VL 34 IS 2 BP 16 EP + DI 10.2307/3337911 PG 0 WC Art SC Art GA 480QA UT WOS:000171472200002 ER PT J AU Wijesinghe, DK Whigham, DF AF Wijesinghe, DK Whigham, DF TI Nutrient foraging in woodland herbs: A comparison of three species of Uvularia (Liliaceae) with contrasting belowground morphologies SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE clonal plants; environmental heterogeneity; foraging; patch selection; Uvularia perfoliata; Uvularia puberula; Uvularia sessilifolia ID CLONAL PLANTS; PLASTICITY; HETEROGENEITY; PERFOLIATA; GROWTH; CONSEQUENCES; ACQUISITION; ENVIRONMENT; GENETICS; ECOLOGY AB We compared the ability of three closely related species, Uvularia perfoliata, U. sessilifolia, and U. puberula, to forage and explore patches in nutritionally homogeneous and heterogeneous environments. The species differed in type and function of plagiotropic stems and the extent of clonality and physiological integration. Our aim was to determine (1) whether selective placement of roots in high-nutrient patches, i.e.. foraging, was accompanied by facilitatory morphological changes such as internode elongation or increased branching, (2) whether foraging ability of species depended on the extent of physiological integration, and (3) how variability in environmental quality influenced the performance of each species. We studied the growth of each species over two seasons in experimental environments. Uvularia perfoliata and U. puberula foraged in high-nutrient patches in heterogeneous environments. Uvularia sessilifolia did not show selective placement of roots. The two clonal species, U perfoliata and U. sessilifolia, did not show any changes in architectural traits predicted to facilitate foraging. The nonclonal species, U. puberula, was the strongest forager and the most physiologically integrated species, U. sessilifolia, was the weakest forager, in line with the view that physiological integration limits foraging efficiency. Variability in environmental quality had little effect on the performance of the three species. Yield and estimators of fitness were not greater in treatments where more high-quality patches were encountered consecutively than in treatments where fewer high-quality patches were encountered consecutively during growth. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. OI Whigham, Dennis/0000-0003-1488-820X NR 37 TC 12 Z9 12 U1 0 U2 8 PU BOTANICAL SOC AMER INC PI ST LOUIS PA PO BOX 299, ST LOUIS, MO 63166-0299 USA SN 0002-9122 EI 1537-2197 J9 AM J BOT JI Am. J. Bot. PD JUN PY 2001 VL 88 IS 6 BP 1071 EP 1079 DI 10.2307/2657090 PG 9 WC Plant Sciences SC Plant Sciences GA 443WG UT WOS:000169364900014 PM 11410472 ER PT J AU Goodyear, FH AF Goodyear, FH TI Between Amateur and aesthete: The legitimization of photography as art in America, 1880-1900 SO AMERICAN STUDIES INTERNATIONAL LA English DT Book Review C1 Smithsonian Amer Art Museum, Washington, DC USA. RP Goodyear, FH (reprint author), Smithsonian Amer Art Museum, Washington, DC USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU GEORGE WASHINGTON UNIV PI WASHINGTON PA AMERICAN STUDIES PROGRAM, WASHINGTON, DC 20052 USA SN 0883-105X J9 AM STUD INT JI Am. Stud. Int. PD JUN PY 2001 VL 39 IS 2 BP 102 EP 103 PG 2 WC History SC History GA 446TZ UT WOS:000169531400016 ER PT J AU Larsen, SS Brodie, JP Huchra, JP Forbes, DA Grillmair, CJ AF Larsen, SS Brodie, JP Huchra, JP Forbes, DA Grillmair, CJ TI Properties of globular cluster systems in nearby early-type galaxies SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : elliptical and lenticular, cD; galaxies : evolution; galaxies : star clusters ID HUBBLE-SPACE-TELESCOPE; MASSIVE STAR-CLUSTERS; LUMINOSITY FUNCTION; METALLICITY DISTRIBUTION; PLANETARY-NEBULAE; LOCAL GROUP; WASHINGTON PHOTOMETRY; ANTENNAE GALAXIES; STANDARD CANDLES; SPIRAL GALAXIES AB We present a study of globular clusters (GCs) in 17 relatively nearby early-type galaxies, based on deep F555W and F814W images from the Wide Field Planetary Camera 2, on board the Hubble Space Telescope. A detailed analysis of color distributions, cluster sizes, and luminosity functions is performed and compared with GCs in the Milky Way. In nearly all cases, a KMM test returns a high confidence level for the hypothesis that a sum of two Gaussians provides a better Dt to the observed color distribution than a single Gaussian, although histograms of the (V - I)(0) distribution are not always obviously bimodal. The blue and red peak colors returned by the KMM test are both found to correlate with absolute host galaxy B-band magnitude and central velocity dispersion (at about the 2-3 sigma level). Red GCs are generally smaller than blue GCs by about 20%. The size difference is seen at all radii at least out to 4' and within sub-bins in (V - I)(0) color, and exists also in the Milky Way and Sombrero (M104) spiral galaxies. Fitting t(5) functions to the luminosity functions of blue and red GC populations separately, we find that the V-band turnover of the blue GCs is brighter than that of the red ones by about 0.3 mag on the average, as expected if the two GC populations have similar ages and mass distributions but different metallicities. Brighter than the turnover at M(V)similar to -7.5, the luminosity functions (LFs) are well approximated by power laws with an exponent of about -1.75. This is similar to the LF for young star clusters, suggesting that young and old globular clusters form by the same basic mechanism. We discuss scenarios for GC formation and conclude that our data appear to favor in situ models in which all GCs in a galaxy formed after the main body of the protogalaxy had assembled into a single potential well. C1 Univ Calif Santa Cruz, Lick Observ, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Swinburne Univ, Hawthorn, Vic 3122, Australia. CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. RP Larsen, SS (reprint author), Univ Calif Santa Cruz, Lick Observ, Dept Astron & Astrophys, 477 Clark Kerr Hall, Santa Cruz, CA 95064 USA. NR 99 TC 285 Z9 286 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 JUN PY 2001 VL 121 IS 6 BP 2974 EP 2998 DI 10.1086/321081 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444FC UT WOS:000169387500008 ER PT J AU Maoz, D Barth, AJ Ho, LC Sternberg, A Filippenko, AV AF Maoz, D Barth, AJ Ho, LC Sternberg, A Filippenko, AV TI An ultraviolet through infrared look at star formation and super star clusters in two circumnuclear starburst rings SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 1512, NGC 5248); galaxies : starburst; galaxies : star clusters ID SPACE-TELESCOPE OBSERVATIONS; H-II REGIONS; GLOBULAR-CLUSTERS; ANTENNAE GALAXIES; NEARBY GALAXIES; LUMINOSITY FUNCTION; NUCLEAR REGION; FORMING RINGS; IONIZED-GAS; NGC 5253 AB We present broadband (U, V, I, and H) and narrowband (H alpha+[N II] and Pa alpha) images of the circumnuclear starburst rings in two nearby spiral galaxies, NGC 1512 and NGC 5248, obtained with the WFPC2 and NICMOS cameras on HST. Combined with previously published ultraviolet (UV) HST images at 2300 Angstrom, these data provide a particularly wide wavelength range with which to study the properties of the stellar populations, the gas, and the dust in the rings. The young star clusters and the line-emitting gas have different spatial distributions, with some large (50 pc scale) line-emitting regions that have little associated continuum emission, but a Pa alpha equivalent width indicating an embedded stellar population a few megayears old. The observed H alpha /Pa alpha intensity ratios suggest the gas is mixed with dust, making it effective at completely obscuring some of the young clusters. We identify the major (about 500 in each galaxy) compact continuum sources (super star clusters and individual stars) and analyze their spectral energy distributions (SEDs) from 0.2 to 1.6 mum by fitting them with a grid of spectral synthesis models with a range of ages and dust extinction. Most of the visible clusters are only mildly reddened, with A(V) = 0 to 1 mag, suggesting that the processes that clear out the gas and dust of the stellar birth clouds are efficient and fast. The patchiness of the dust distribution makes it difficult to reliably estimate the star formation rate, based on UV continuum slope or hydrogen emission-line ratios, in starbursts such as these. The cluster SEDs are consistent with a range in ages, from 1 to 300 Myr, but with only a minority older than a few tens of megayears. We point out an age bias, the result of the steep luminosity function of the clusters combined with the fading of clusters as they age, which causes young clusters to be overrepresented at any luminosity. Accounting for this bias, the fraction of old clusters is consistent with continuous star formation in the rings over the past similar to 300 Myr. Because of the uncertainties in dating the clusters, we cannot rule out episodic, similar to 20 Myr long bursts of star formation, but the presence of UV-bright rings in about 10% of spiral galaxies argues against this possibility. Although most of the observed SEDs are well fitted by a range of models, some of the brightest young clusters have excess emission in the IR that is not predicted by the models and may be thermal reradiation by circumstellar dust. The cluster mass functions follow a power-law distribution with index -2, similar to that recently derived for the starburst in the merging Antennae galaxies, and extending to similar to 10(5) The lack of a mass scale means that subsequent evolution of the mass function is required, if some of the SSCs are to evolve into globular clusters. The clusters are spatially unresolved or marginally resolved, corresponding to V-band Gaussian radii of less than a few parsecs, at an assumed distance of 10 Mpc. In NGC 5248, we report a previously unknown, 60 pc radius, inner emission-line ring, and in NGC 1512, a peculiar compact (0."1 diameter) source with an H alpha+[N II] equivalent width of similar to 7000 Angstrom, which may be a so-called Balmer-dominated supernova remnant. C1 Columbia Univ, Dept Astron, New York, NY 10027 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, IL-69978 Tel Aviv, Israel. RP Maoz, D (reprint author), Columbia Univ, Dept Astron, 550 W 120th St, New York, NY 10027 USA. EM dani@wise.tau.ac.il; abarth@cfa.harvard.edu; lho@ociw.edu; amiel@wise.tau.ac.il; alex@astro.berkeley.edu NR 85 TC 73 Z9 73 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2001 VL 121 IS 6 BP 3048 EP 3074 DI 10.1086/321080 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444FC UT WOS:000169387500014 ER PT J AU Olsen, KAG Kim, S Buss, JF AF Olsen, KAG Kim, S Buss, JF TI A comprehensive look at LH 72 in the context of the supergiant shell LMC 4 SO ASTRONOMICAL JOURNAL LA English DT Article DE Magellanic Clouds; ISM : bubbles; HII regions; ISM : HI; stars : early-type ID LARGE-MAGELLANIC-CLOUD; SHAPLEY-CONSTELLATION-III; STAR-FORMATION; STANDARD STARS; ASSOCIATIONS; PHOTOMETRY; GALAXIES; CLUSTER; REGION; DISK AB Stellar spectroscopy, UBV photometry, H alpha imaging, and analysis of data from the Australia Telescope Compact Array H I survey of the LMC are combined in a study of the LMC OB association LH 72 and its surroundings. LH 72 lies on the rim of a previously identified H I shell, SGS 14, and in the interior of LMC 4, one of the LMC's largest known supergiant shells. Our analysis of the H I data finds that SGS 14 is expanding with a velocity of v(exp) similar to 15 km s(-1), giving it an expansion age of similar to 15 Myr. Through the stellar spectroscopy and photometry, we find similar ages for the oldest stars of LH 72, similar to 15-30 Myr. We confirm that LH 72 contains an age spread of similar to 15-30 Myr, similar to the range in ages of stars derived for the entire surrounding supergiant shell. Combining analysis of the O and B stars with H alpha imaging of the H II region DEM 228, we find that DEM 228 accounts for only 60% of the available ionizing Lyman continuum photons. Comparing the distribution of ionized gas with that of the H I, we find that DEM 228 and LH 72 are offset by similar to1'-2' from the peak 21 cm emission toward the interior of SGS 14. Taken together, these results imply that SGS 14 has cleared its interior of gas and triggered the formation of LH 72. On the basis of our results, we suggest that LMC 4 was not formed as a unit but by overlapping shells, such as SGS 14, and that LH 72 will evolve to produce a stellar arc similar to others seen within LMC 4. C1 Cerro Tololo Interamer Observ, La Serena, Chile. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Wisconsin, Appleton, WI 54915 USA. RP Olsen, KAG (reprint author), Cerro Tololo Interamer Observ, Casilla 603, La Serena, Chile. EM kolsen@noao.edu; skim@cfa.harvard.edu; jeremy@sunspot.phys.uwosh.edu NR 41 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 JUN PY 2001 VL 121 IS 6 BP 3075 EP 3088 DI 10.1086/321092 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444FC UT WOS:000169387500015 ER PT J AU Mochejska, BJ Kaluzny, J Stanek, KZ Sasselov, DD Szentgyorgyi, AH AF Mochejska, BJ Kaluzny, J Stanek, KZ Sasselov, DD Szentgyorgyi, AH TI Direct distances to nearby galaxies using detached eclipsing binaries and cepheids. VII. Additional variables in the field M33A discovered with image subtraction (vol 121, pg 2032, 2001) SO ASTRONOMICAL JOURNAL LA English DT Correction C1 N Copernicus Astron Ctr, Brno, Czech Republic. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mochejska, BJ (reprint author), N Copernicus Astron Ctr, Brno, Czech Republic. NR 1 TC 3 Z9 3 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 JUN PY 2001 VL 121 IS 6 BP 3284 EP 3284 DI 10.1086/321097 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 444FC UT WOS:000169387500033 ER PT J AU Castelli, F Kurucz, RL AF Castelli, F Kurucz, RL TI Ultraviolet spectra for lambda Boo (HD 125162) computed with H(2) opacities and Lyman-alpha H-H and H-H(+) opacities SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : atmospheres; stars : fundamental parameters; stars : individuals : HD 125162 (lambda Boo); ultraviolet : stars ID EFFECTIVE TEMPERATURES; CHEMICAL-COMPOSITION; STARS; HYDROGEN; ABUNDANCES; GRAVITIES; CATALOG; SYSTEM; LINES; ATOM AB New opacity distribution functions (ODF) have been computed for use with the ATLAS9 model atmosphere code of Kurucz. One of the improvements upon the Kurucz (1990) ODFs is the addition to the line blanketing of the Lyman-alpha H-H and H-H(+) quasi-molecular absorptions near 1600 Angstrom and 1400 Angstrom. New-ODF fluxes are expected to reproduce the ultraviolet observations of lambda Boo stars and metal-poor A-type stars in a more realistic way than previous computations did. In this paper we compare low- and high-resolution IUE observations of lambda Boo (HD 125162, HR 5351) with fluxes and synthetic spectra based on ATLAS9 models and new-ODFs, which were computed for [M/H] = -2.0 for all the elements, except CNO. For C, N, and O, abundances log(N(elem)/N(tot)) equal to -3.85, -3.99, and -3.11, respectively, were adopted. We selected lambda Boo in order to compare results from the new-ODFs with those from Allard et al. (1998a, 1998b), who tested their semi-classical computations of the H-H and H-H(+) quasi-molecular absorptions on this star. The analysis of the IUE high-resolution spectrum has shown that lines of H(2) are a very important source of line opacity for lambda Boo shortward 1600 Angstrom. When both atomic and molecular lines are considered, the slope of the observed energy distribution is well reproduced in the whole region 1300-3000 Angstrom by the new-ODF model, but the H-H quasi-molecular absorption at 1600 Angstrom is computed about 10% too strong. The fit of the low-resolution IUE image SWP17872 to a small grid of new-ODF models gives parameters T(eff) = 8650 K, log g = 4.0, while the fit of the high-resolution image SWP42081, rebinned at the low resolution wavelength step size, gives parameters T(eff) = 8500 K, log g = 4.0. These last parameters are in close agreement with T(eff) = 8550 K, log g = 4.1 obtained by fitting the visible energy distribution. The different IUE images are discussed. C1 CNR, Grp Nazl Astron, I-34131 Trieste, Italy. Osserv Astron Trieste, I-34131 Trieste, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Castelli, F (reprint author), CNR, Grp Nazl Astron, Via GB Tiepolo 11, I-34131 Trieste, Italy. EM castelli@ts.astro.it; rkurucz@cfa.harvard.edu NR 41 TC 17 Z9 17 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 2001 VL 372 IS 1 BP 260 EP 275 DI 10.1051/0004-6361:20010445 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 454FT UT WOS:000169962300032 ER PT J AU Brunetti, G Cappi, M Setti, G Feretti, L Harris, DE AF Brunetti, G Cappi, M Setti, G Feretti, L Harris, DE TI Anisotropic inverse Compton scattering in powerful radio galaxies: The case of 3C 295 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE radiation mechanisms : non-thermal; galaxies : active; galaxies : individual : 3C 295; galaxies : magnetic fields; radio continuum : galaxies; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; X-RAY OBSERVATIONS; HOT-SPOTS; CYGNUS-A; ENERGY-DISTRIBUTIONS; COOLING FLOW; SPECTRA; CLUSTER; 3C-295; LOBES AB Inverse Compton (IC) scattering of nuclear photons with relativistic electrons in the lobes of powerful radio galaxies and quasars can give detectable extended X-ray emission from the radio lobes if relativistic electrons with a Lorentz factor gamma < 300 are present (Brunetti et al. 1997). In general these electrons are not detected since they emit synchrotron radiation at frequencies below the radio band, so that the study of this effect provides a unique tool to measure the energy distribution of the electron population in the radio lobes at < 1000 energies. In this paper we reanalyze the Chandra observation of the powerful and compact radio galaxy 3C 295 for which the IC scattering of nuclear photons is expected to be an important mechanism. We find strong evidence for extended and asymmetrical X-ray emission associated with the radio lobes in the energy band 0.1-2 keV. We show that both the luminosity and morphology of the extended X-ray emission associated with the radio lobes, not compatible with other X-ray mechanisms, can be best interpreted by the IC scattering with nuclear photons. We also show that the relativistic electron energy distribution obtained from the synchrotron radio emission can be extrapolated down to similar to 100 thus providing a first direct evidence on the electron spectrum in the lobes down to lower energies. C1 Univ Bologna, Dipartimento Astron, I-40126 Bologna, Italy. CNR, Ist Radioastron, I-40129 Bologna, Italy. CNR, Ist TeSRE, I-40129 Bologna, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Brunetti, G (reprint author), Univ Bologna, Dipartimento Astron, Via Ranzani 1, I-40126 Bologna, Italy. EM gbrunetti@astbo1.bo.cnr.it RI Cappi, Massimo/F-4813-2015; OI Cappi, Massimo/0000-0001-6966-8920; Feretti, Luigina/0000-0003-0312-6285; Brunetti, Gianfranco/0000-0003-4195-8613 NR 56 TC 37 Z9 37 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 2001 VL 372 IS 3 BP 755 EP 767 DI 10.1051/0004-6361:20010484 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 454HF UT WOS:000169966600010 ER PT J AU Smith, RK Cox, DP AF Smith, RK Cox, DP TI Multiple supernova remnant models of the Local Bubble and the soft X-ray background SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE ISM : structure; MHD; supernova remnants; X-rays : ISM ID INTERSTELLAR-MEDIUM; HOT GAS; CYGNUS LOOP; EMISSION; ABUNDANCES; EVOLUTION; GALAXY; DUST; HALO; TEMPERATURE AB This paper examines the possibility that a series of two or three supernovae in the diffuse interstellar medium might be capable of generating a long-lived hot diffuse bubble with characteristics like those inferred for the Local Bubble surrounding the Sun. Several examples of multiple supernova remnants are explored with a one-dimensional hydrocode able to follow the nonequilibrium ionization and dust destruction. The results are generalized via scaling parameters, and a set of input parameters are identified, which should in fact lead to a bubble satisfying all known constraints on size, external pressure, external density, X-ray surface brightness and band ratios, the upper limit to X-ray emission in the 0.5-1 keV range, and the O VI absorption line characteristics. The exploratory models are a unique example of the detailed behavior of hot interstellar bubbles, and their characteristics are presented in considerable detail. Included are the distributions of temperature, density, and pressure, as well as the evolutions of those distributions with time, the evolution of bubble radius during both expansion and contraction, the evolution of the X-ray emission in observed bands and specific observed lines, a diagnostic for normalizing the X-ray surface brightness to radius, pressure, and central temperature, the radial dependence of X-ray emissivity, the full X-ray and EUV spectrum, the equivalent widths of potentially observable absorption lines, the specific characteristics of the O VI absorption (column density, centroid velocity, width), the electron column density, the emission line intensities for O VI, Fe X, and Fe XIV, the degree to which dust can be expected to have been destroyed, and the effects of incomplete dust destruction on everything else. Observations have shown that the emission lines of iron from the Local Bubble are weak or absent. This is somewhat surprising, since considerable grain destruction is expected, even if only by thermal sputtering. The result is similar to other hints that much of the iron is in its own population of dust and is very resistant to destruction. In our models, having iron alone depleted by a factor of 10 makes it much easier to accommodate the X-ray emission characteristics. Having a successful model also requires that thermal conduction within the hot bubble occurs at roughly half of its full classical rate. For substantially lower thermal conductivity, the temperature is too high to get the spectral characteristics right, and the density is too low at the highest allowed pressure to achieve the observed brightness. Our fiducial model assumes that three supernovae took place in the vicinity of the Sun over a period of 3 million years, the last having occurred a few million years ago. We show that such accidental occurrences should be sufficiently common to provide about 1 chance in 30 (with considerable uncertainty) of being found within one. Certainly supernovae occur outside of OB associations, and direct evidence for a nearby supernova some 5 million years ago that could have been responsible for the latest reheating of the Local Bubble has recently been found in the excess abundance of Fe-60 in a deep ocean ferromanganese crust. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. RP Smith, RK (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. NR 81 TC 71 Z9 71 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 2001 VL 134 IS 2 SU S BP 283 EP 309 DI 10.1086/320850 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JD UT WOS:000169280700004 ER PT J AU Gordon, VD McCarthy, MC Apponi, AJ Thaddeus, P AF Gordon, VD McCarthy, MC Apponi, AJ Thaddeus, P TI Rotational spectra of sulfur-carbon chains. I. The radicals C4S, C5S, C6S, C7S, C8S, and C9S SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE ISM : molecules; line : identification; molecular data; molecular processes; radio lines : ISM ID TRANSFORM MICROWAVE SPECTROSCOPY; DENSE INTERSTELLAR CLOUDS; LINEAR SILICON CARBIDES; LABORATORY DETECTION; ASTRONOMICAL IDENTIFICATION; CHEMISTRY; TMC-1; IRC+10216; MOLECULES; CLUSTERS AB The linear carbon-chain radicals C6S, C7S, C8S, and C9S have been detected in a supersonic molecular beam by Fourier transform microwave spectroscopy, and measurements of the previously studied chains C4S and C5S have been extended using the same technique. The electronic ground state, as predicted, is found to be a triplet for those with an even number of carbon atoms and a singlet for those with an odd number. The microwave spectra of all six chains have been fully characterized, and spectroscopic constants, including fine-structure constants where applicable, have been determined to high precision. Transitions from the J = N and J = N - 1 fine-structure levels of C4S have been detected for the first time, and the lengths of the individual bonds of C4S have been determined from its isotopic species. The carbon-sulfur chains here are all highly polar, calculated to possess dipole moments in the 4-7 D range; all are plausible candidates for astronomical detection. The spectroscopic constants determined from this work allow transitions up to 40 GHz to be calculated with an uncertainty of less than 1 km s(-1) for each chain. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Gordon, VD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI McCarthy, Michael/0000-0001-9142-0008 NR 33 TC 33 Z9 33 U1 0 U2 5 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 JUN PY 2001 VL 134 IS 2 SU S BP 311 EP 317 DI 10.1086/320853 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JD UT WOS:000169280700005 ER PT J AU Dere, KP Landi, E Young, PR Del Zanna, G AF Dere, KP Landi, E Young, PR Del Zanna, G TI Chianti - An atomic database for emission lines. IV. Extension to X-ray wavelengths SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; stars : atmospheres; Sun : atmosphere ID ELECTRON-IMPACT EXCITATION; FINE-STRUCTURE TRANSITIONS; EXPERIMENTAL LEVEL VALUES; NEON-LIKE IONS; EFFECTIVE COLLISION STRENGTHS; HELIUM-LIKE IONS; HE-LIKE IONS; N = 2; OSCILLATOR-STRENGTHS; RATE COEFFICIENTS AB CHIANTI provides a database of atomic energy levels, wavelengths, radiative transition probabilities, and electron excitation data for a large number of ions of astrophysical interest. It also includes a suite of Interactive Data Language programs to calculate optically thin synthetic spectra and to perform spectral analysis and plasma diagnostics. This database allows the calculation of theoretical line emissivities necessary for the analysis of optically thin emission-line spectra. The first version (1.01) of the CHIANTI database was released in 1996 and published by Dere et al. in 1997 as Paper I in this series. The second version, released in 1999 by Landi et al., included continuum emission and data for additional ions. Both versions of the CHIANTI database have been used extensively by the astrophysical and solar communities to analyze emission-line spectra from astrophysical sources. Now the CHIANTI database has been extended to wavelengths shorter than 50 Angstrom by including atomic data for the hydrogen and helium isoelectronic sequences, inner-shell transitions and satellite lines, and several other ions. In addition, some of the ions already present in the database have been updated and extended with new atomic data from published calculations. C1 USN, Res Lab, Washington, DC 20375 USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cent Lancashire, Ctr Astrophys, Preston PR1 2HE, Lancs, England. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. RP Dere, KP (reprint author), USN, Res Lab, 4555 Overlook Ave SW, Washington, DC 20375 USA. RI Landi, Enrico/H-4493-2011 NR 90 TC 150 Z9 151 U1 1 U2 4 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 JUN PY 2001 VL 134 IS 2 SU S BP 331 EP 354 DI 10.1086/320854 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JD UT WOS:000169280700008 ER PT J AU Bektas, Y AF Bektas, Y TI Displaying the American genius: the electromagnetic telegraph in the wider world SO BRITISH JOURNAL FOR THE HISTORY OF SCIENCE LA English DT Review ID JAPAN AB Shortly after he made a working model of his electromagnetic telegraph in 1837, Samuel F. B. Morse and his associates began an intense initiative to publicize and market it to the world. At first, using the social skills he had learned during his years as a portrait painter, Morse strove to gain the support of the upper classes in Europe. He and his agents saw the physical seats of institutions such as palaces and academy lecture halls as the most desirable settings for public demonstrations of the apparatus. To win public support back at home, they made a point of politicizing the invention by presenting it as an example of American mechanical ingenuity. Their efforts to market the invention were not confined to the United States, Britain and France, but included the rest of Europe and the Near and Far East as well. The telegraph promoters, presuming an oriental fascination with magic, endeavoured to exploit potential markets in the East, particularly the Ottoman Empire and Japan, by making the most of its wondrous effects. The Sultan's palace provided a most exotic setting for display of the electromagnetic telegraph. C1 Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. RP Bektas, Y (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. NR 109 TC 9 Z9 9 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0007-0874 J9 BRIT J HIST SCI JI Br. J. Hist. Sci. PD JUN PY 2001 VL 34 IS 121 BP 199 EP 232 PN 2 PG 34 WC History & Philosophy Of Science SC History & Philosophy of Science GA 532MY UT WOS:000174480100004 ER PT J AU Jackson, R AF Jackson, R TI 'Frank' SO CALLALOO LA English DT Poetry C1 Smithsonian Inst, Washington, DC 20560 USA. RP Jackson, R (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU JOHNS HOPKINS UNIV PRESS PI BALTIMORE PA JOURNALS PUBLISHING DIVISION, 2715 NORTH CHARLES ST, BALTIMORE, MD 21218-4319 USA SN 0161-2492 J9 CALLALOO JI Callaloo PD SUM PY 2001 VL 24 IS 3 BP 774 EP 775 DI 10.1353/cal.2001.0156 PG 2 WC Literature, African, Australian, Canadian SC Literature GA 466UA UT WOS:000170663500044 ER PT J AU Kendall, MS Wolcott, DL Wolcott, TG Hines, AH AF Kendall, MS Wolcott, DL Wolcott, TG Hines, AH TI Reproductive potential of individual male blue crabs, Callinectes sapidus, in a fished population: depletion and recovery of sperm number and seminal fluid SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID CHESAPEAKE-BAY; CHIONOECETES-OPILIO; RATHBUN; COMPETITION; SIZE; SPERMATOPHORES; MATURITY; AUTOTOMY; MAJIDAE; MOLT AB We evaluated the depletion and recovery rates of sperm number and vas deferens weight following mating for male Callinectes sapidus both below (< 127 mm carapace width) and well above (> 140 mm) the fishery size limit for hard crabs in Chesapeake Bay (127 mm). Large males had low sperm count and vas deferens weight immediately after mating and required approximately 9-20 days to fully recover. After mating, small males had significant reduction in sperm number despite no significant change in vas deferens weight. Furthermore, small males with completely recovered seminal stores had significantly lower vas deferens weight than fully recovered large males but did not differ significantly from large males in number of sperm. The changes in vas deferens weight and sperm count following experimental mating suggest that large males delivered 21 times as much seminal fluid and 2.25 times as much sperm as small males. Field collections in a subestuary of Chesapeake Bay revealed that the majority (50-90%) of males had extremely low vas deferens weight relative to males with fully recovered sperm volume. Since the fishery targets males primarily, reducing both the number and average size of males in the population, many females may be mated with small or recently mated males that transfer less seminal material. C1 NOAA, Natl Ocean Serv, Ctr Coastal Monitoring & Assessment, Silver Spring, MD 20910 USA. N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Raleigh, NC 27695 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Kendall, MS (reprint author), NOAA, Natl Ocean Serv, Ctr Coastal Monitoring & Assessment, 1305 EW highway N-SCI1, Silver Spring, MD 20910 USA. NR 32 TC 48 Z9 51 U1 0 U2 9 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD JUN PY 2001 VL 58 IS 6 BP 1168 EP 1177 DI 10.1139/cjfas-58-6-1168 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 435PU UT WOS:000168890500012 ER PT J AU Bowen, WD Ellis, SL Iverson, SJ Boness, DJ AF Bowen, WD Ellis, SL Iverson, SJ Boness, DJ TI Maternal effects on offspring growth rate and weaning mass in harbour seals SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID ANTARCTIC FUR SEALS; SOUTHERN ELEPHANT SEALS; PHOCA-VITULINA; HALICHOERUS-GRYPUS; ENERGY ALLOCATION; PUP GROWTH; GREY SEALS; BODY-MASS; SEX-RATIO; LACTATION AB We studied maternal effects on offspring traits during lactation in harbour seals (Phoca vitulina) on Sable Island, Nova Scotia, from 1988 to 1996. Duration of lactation was correlated with rate of pup mass gain (r = -0.34, n = 116) and weaning mass (r = 0.29, n = 154). Pups that grew faster had shorter nursing periods, whereas those that attained higher weaning masses nursed for a greater number of days. Pup sex did not affect patterns of maternal effects. The pups of young females (4-6 years old) gained mass at a constant but lower rate (0.56 kg/d) than the pups of older females through midlactation (0.74-0.78 kg/d; n = 75). In older females, rates of pup mass gain decelerated between mid and late lactation. Although maternal age did not directly affect weaning mass of pups, path analysis showed that maternal age acted on weaning mass through intermediary traits. Lighter females gave birth to smaller and slower growing pups, but invested relatively more than heavier females (n = 153). Effects of maternal postpartum mass on weaning mass (n = 100) were weaker in harbour seals than in phocids that fast during lactation, but apparently stronger than in otariids that forage during lactation, suggesting that the strength of maternal effects is influenced by lactation strategy. C1 Fisheries & Oceans Canada, Bedford Inst Oceanog, Marine Fish Div, Dartmouth, NS B2Y 4A2, Canada. Dalhousie Univ, Dept Biol, Halifax, NS B3H 4J1, Canada. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Bowen, WD (reprint author), Fisheries & Oceans Canada, Bedford Inst Oceanog, Marine Fish Div, POB 1006, Dartmouth, NS B2Y 4A2, Canada. RI Bowen, William/D-2758-2012 NR 60 TC 35 Z9 36 U1 0 U2 16 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD JUN PY 2001 VL 79 IS 6 BP 1088 EP 1101 DI 10.1139/cjz-79-6-1088 PG 14 WC Zoology SC Zoology GA 451AF UT WOS:000169776500020 ER PT J AU Power, RA Power, ML Layne, DG Jaquish, CE Oftedal, OT Tardif, SD AF Power, RA Power, ML Layne, DG Jaquish, CE Oftedal, OT Tardif, SD TI Relations among measures of body composition, age, and sex in the common marmoset monkey (Callithrix jacchus) SO COMPARATIVE MEDICINE LA English DT Article ID RANGING RHESUS MACAQUES; SAVANNAH BABOONS; RATS; OBESITY; SIZE; FAT; WEIGHT; ADIPOSITY; MASS; ADULTHOOD AB Few studies of body composition have been done in New World primates. In the study reported here, four methods of assessing body composition (body weight, anthropometry, labeled-water dilution, and total body electroconductivity) were compared in 20 marmosets, aged 0.96 to 7.97 years. Males and females did not differ in any measure (P > 0.05). Body weight ranged from 272 to 466 g, and body fat estimates varied from 1.6 to 19.5%. Strong positive correlations were observed between total body water and total body electroconductivity (R-2 = 0.77), body weight and fat-free mass (males R-2 = 0.95; females R-2 = 0.91), and body weight and fat mass (males R-2 = 0.86; females R-2 = 0.85; P < 0.01). Male and female slopes were equivalent (P > 0.05) for the regressions of fat and fat-free mass against body weight. Positive correlations also were observed between girth measures and fat-free mass (R-2 = 0.48 to 0.78) and fat mass (R-2 = 0.60 to 0.74; P < 0.01). A good second-order polynomial relationship was observed between age and fat-free mass for the combined sample (R-2 = 0.64). Results indicated that: subjects were lean; there was no sexual dimorphism relative to measures; body weight provided a reliable estimate of fat and fat-free mass; and within-subject body weight changes reflected a similar relationship between body weight and fat-free mass as did that across subjects. C1 Univ Florida, Coll Vet Med, Dept Physiol Sci, Gainesville, FL 32610 USA. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. Amer Coll Obstetricians & Gynecologists, Washington, DC 20024 USA. Kent State Univ, Dept Biol Sci, Kent, OH 44242 USA. NHLBI, NIH, Bethesda, MD 20892 USA. RP Power, RA (reprint author), Univ Florida, Coll Vet Med, Dept Physiol Sci, POB 100144, Gainesville, FL 32610 USA. FU NCRR NIH HHS [R01-RR02022] NR 48 TC 25 Z9 25 U1 2 U2 10 PU AMER ASSOC LABORATORY ANIMAL SCIENCE PI MEMPHIS PA 9190 CRESTWYN HILLS DR, MEMPHIS, TN 38125 USA SN 0023-6764 J9 COMPARATIVE MED JI Comparative Med. PD JUN PY 2001 VL 51 IS 3 BP 218 EP 223 PG 6 WC Veterinary Sciences; Zoology SC Veterinary Sciences; Zoology GA 449CG UT WOS:000169666300006 PM 11924775 ER PT J AU Roubik, DW AF Roubik, DW TI Ups and downs in pollinator populations: When is there a decline? SO CONSERVATION ECOLOGY LA English DT Article DE ENSO; Euglossini; abundance variability; bees; census techniques; diversity; pollinators; trends; tropical-temperate comparisons ID MALE EUGLOSSINE BEES; AMAZONIAN FOREST FRAGMENTS; ORCHID-BEES; TROPICAL FOREST; ECOLOGY; APIDAE; HYMENOPTERA; ABUNDANCE; PANAMA; FIELD AB Plant-pollinator systems inherently possess wide variation that limits the applicability of surveys on population dynamics or diversity. Stable habitats are scarcely studied, whereas dynamics in unprotected habitats are less predictable or more compromised by exotic organisms (Apis, in the case of bee surveys). An extensively replicated, long-term study of orchid-bees (Euglossini) was made in protected tropical moist forest in Panama. Over 47,000 bees were recorded in 124 monthly censuses employing 1952 counts. No aggregate trend in abundance occurred (from 1979 to 2000), although four individual species declined, nine increased, 23 showed no change, and species richness was stable. No rare or parasitic species showed decreasing trends, while the most common of the set of bee species studied gradually declined. Biodiversity therefore increased. Recorded variability included 300% (fourfold) differences in bee abundance among years, and changes in species abundance up to 14-fold. Surveys in dry and wet seasons (N = 17 and 18 years, 29 and 31 species, respectively) indicated no numerical changes in the bee assemblage over 21 years. El-Ni (n) over tildeo climatic events led to brief increases in bee abundance. This detailed survey is deconstructed to assess sampling rigor and strategies, particularly considering the recorded local differences within a single forest. Year-to-year shifts in bee abundance for three tropical and five temperate bee censuses were comparable. In short studies (2-4 years) and during longer studies (17-21 years), 59 species that included solitary, social, and highly social bees had mean abundances that varied by factors of 2.06 for temperate bees and 2.16 for tropical bees. "Normal" bee populations commonly halved or doubled in 1-yr intervals. Longer term data are only available for the tropics. Stochastic variation and limitations of monitoring methods suggest that minimum series of four years (i.e., three intervals) of several counts during the active season may demonstrate genuine trends. Longer term, continuous studies are still needed for meaningful insights on pollinator population shifts in nature. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Roubik, DW (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 37 TC 68 Z9 76 U1 2 U2 29 PU RESILIENCE ALLIANCE PI WOLFVILLE PA ACADIA UNIV, BIOLOGY DEPT, WOLFVILLE, NS B0P 1X0, CANADA SN 1195-5449 J9 CONSERV ECOL JI Conserv. Ecol. PD JUN PY 2001 VL 5 IS 1 AR 2 PG 29 WC Ecology SC Environmental Sciences & Ecology GA 458XV UT WOS:000170221500004 ER PT J AU Kaspari, M Pickering, J Windsor, D AF Kaspari, M Pickering, J Windsor, D TI The reproductive flight phenology of a neotropical ant assemblage SO ECOLOGICAL ENTOMOLOGY LA English DT Article DE alates; ants; autocorrelation; constraints; diversity; phenology; quantile regression; rainfall; temperature; traps; tropics ID TROPICAL FOREST; HARVESTER ANTS; COSTA-RICA; ABUNDANCE; HYMENOPTERA; FORMICIDAE; COMMUNITY; POGONOMYRMEX; DISTURBANCE; PATCHINESS AB 1. Alate flights reflect an ant colony's investment in sexual reproduction and dispersal yet little is known about community-wide patterns of alate phenology. Two Malaise traps (for 2 years) and two light traps (for 1 year) were used to explore the flight phenologies of 22 common neotropical species from Barro Colorado Island, Panama. 2. The traps caught 23 182 individuals and 286 species/morphospecies. The two trap methods shared only 18 species. Samples also differed in sexual composition: light trap samples were 80% female, Malaise trap samples were 2.6% female. 3. Of 22 common species, all but one flew over half the year, with about half flying every month of the year. These data, combined with a literature review, suggest a latitudinal gradient in alate flight season: one north temperate assemblage (42 degreesN) averaged 1.6 lunar months per species. The ever-warm tropical year provides a larger flight window that allows a diversity of phenologies, from continuous to strongly pulsed. 4. Rainfall was correlated with alate flights in one-third of the species. Quantile regression suggested that high weekly rainfall was necessary but not sufficient to produce alate flights in about a quarter of the species. 5. By decreasing the number of nests releasing alates on a given day, long flight seasons may lower the probability of finding a mate. At the same time, long flight seasons may increase the opportunity of finding vacant nest sites. High population densities and high incidence of nest disturbance in this community may ameliorate the first cost while enhancing the second benefit. C1 Univ Oklahoma, Dept Zool, Norman, OK 73019 USA. Univ Georgia, Dept Zool, Athens, GA 30602 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Kaspari, M (reprint author), Univ Oklahoma, Dept Zool, 730 Van Vleet Oval,Rm 314, Norman, OK 73019 USA. OI Kaspari, Michael/0000-0002-9717-5768 NR 60 TC 32 Z9 32 U1 2 U2 6 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0307-6946 J9 ECOL ENTOMOL JI Ecol. Entomol. PD JUN PY 2001 VL 26 IS 3 BP 245 EP 257 DI 10.1046/j.1365-2311.2001.00320.x PG 13 WC Entomology SC Entomology GA 439AP UT WOS:000169087100004 ER PT J AU Gallegos, CL AF Gallegos, CL TI Calculating optical water quality targets to restore and protect submersed aquatic vegetation: Overcoming problems in partitioning the diffuse attenuation coefficient for photosynthetically active radiation SO ESTUARIES LA English DT Article ID SEAGRASS DEPTH LIMITS; SCATTERING COEFFICIENTS; NATURAL-WATERS; LIGHT; PHYTOPLANKTON; DEPENDENCE; ABSORPTION; EXTINCTION; TURBIDITY; ESTUARY AB Submersed aquatic vegetation (SAV) is an important component of shallow water estuarine systems that has declined drastically in recent decades. SAV has particularly high light requirements, and losses of SAV have, in many cases, been attributed to increased light attenuation in the water column, frequently due to coastal eutrophication. The desire to restore these valuable habitats to their historical levels has created the need for a simple but accurate management tool for translating light requirements into water quality targets capable of supporting SAV communities. A procedure for calculating water quality targets for concentrations of chlorophyll and total suspended solids (TSS) is derived, based on representing the diffuse attenuation coefficient for photosynthetically active radiation, Kd(PAR), as a linear function of contributions due to water plus colored dissolved organic matter (CDOM), chlorophyll, and TSS. It is assumed that Kd(PAR) conforms to the Lambert-Beer law. Target concentrations are determined as the intersection of a line representing intended reduction of TSS and chlorophyll by management actions, with another line describing the dependence of TSS on chlorophyll at a constant value of Kd(PAR). The validity of applying the Lambert-Beer law to Kd (PAR) in estuarine waters was tested by comparing the performance of a linear model of Kd(PAR) with data simulated using a more realistic model of light attenuation. The linear regression model tended to underestimate Kd(PAR) at high light attenuation, resulting in erroneous predictions of target concentrations at shallow restoration depths. The errors result more from the wide spectral bandwidth of PAR, than from irrecoverable nonlinearities in the diffuse attenuation coefficient per se. In spite of the failure of the Lambert-Beer law applied to Kd(PAR), the variation of TSS with chlorophyll at constant Kj(PAR) determined by the more mechanistic attenuation model was, nevertheless, highly linear. Use of the management tool based on intersecting lines is still possible, but coefficients in the line describing the dependence of TSS on chlorophyll at constant Kd(PAR) must be determined empirically by application of an optical model suitably calibrated for the region of interest. An example application of the procedure to data from the Rhode River, Maryland, indicates that approximately 15% reduction in both TSS and chlorophyll concentrations, or 50% reduction in chlorophyll alone, will be needed to restore conditions for growth of SAV to levels that existed in the late 1960s. C1 Smithsonian Environm Res Ctr, Edgewater, MD 20137 USA. RP Gallegos, CL (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 20137 USA. OI Gallegos, Charles/0000-0001-5112-0166 NR 35 TC 78 Z9 82 U1 2 U2 25 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 2001 VL 24 IS 3 BP 381 EP 397 DI 10.2307/1353240 PG 17 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 457AV UT WOS:000170115700007 ER PT J AU Cibois, A Slikas, B Schulenberg, TS Pasquet, E AF Cibois, A Slikas, B Schulenberg, TS Pasquet, E TI An endemic radiation of Malagasy songbirds is revealed by mitochondrial DNA sequence data SO EVOLUTION LA English DT Article DE adaptive radiation; cytochrome b; Madagascar; molecular phylogeny; Pycnonotidae; Sylviidae; Timaliidae ID MOLECULAR PHYLOGENY; EVOLUTIONARY RATES; MTDNA SEQUENCES; PASSERINE BIRDS; SINGLE-ORIGIN; MADAGASCAR; GENUS; BIOGEOGRAPHY; TOPOLOGIES; TREE AB The bird fauna of Madagascar includes a high proportion of endemic species, particularly among passerine birds (Aves: Passeriformes). The endemic genera of Malagasy songbirds are not allied obviously with any African or Asiatic tare, and their affinities have been debated since the birds first were described. We used mitochondrial sequence data to estimate the relationships of 13 species of endemic Malagasy songbirds, 17 additional songbird species, and one species of suboscine passerine. In our optimal trees, nine of the 13 Malagasy species form a clade, although these birds currently are classified in three different families. In all optimal trees, the sister to this endemic clade is a group of Old World warblers including both African and Malagasy birds. The endemic Malagasy songbird clade rivals other island radiations, including the vangas of Madagascar and the finches of the Galapagos, in ecological diversity. C1 Museum Natl Hist Nat, Lab Zool Mammiferes & Oiseaux, F-75005 Paris, France. Museum Natl Hist Nat, CNRS FR 1541, Serv Systemat Mol, F-75005 Paris, France. Smithsonian Inst, Washington, DC 20008 USA. Field Museum Nat Hist, Chicago, IL 60605 USA. RP Cibois, A (reprint author), Amer Museum Nat Hist, Dept Ornithol, Cent Pk W 79th St, New York, NY 10024 USA. RI Slikas, Beth/E-7275-2013 NR 59 TC 55 Z9 57 U1 1 U2 10 PU SOC STUDY EVOLUTION PI LAWRENCE PA 810 E 10TH STREET, LAWRENCE, KS 66044 USA SN 0014-3820 J9 EVOLUTION JI Evolution PD JUN PY 2001 VL 55 IS 6 BP 1198 EP 1206 PG 9 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 453EF UT WOS:000169903000013 PM 11475055 ER PT J AU Bowen, WD Iverson, SJ Boness, DJ Oftedal, OT AF Bowen, WD Iverson, SJ Boness, DJ Oftedal, OT TI Foraging effort, food intake and lactation performance depend on maternal mass in a small phocid seal SO FUNCTIONAL ECOLOGY LA English DT Article DE body mass; energetics; Harbour Seal; lactation ID HYDROGEN-ISOTOPE-DILUTION; HARBOR SEAL; REPRODUCTIVE EXPENDITURE; HALICHOERUS-GRYPUS; BODY-COMPOSITION; ELEPHANT SEAL; BIGHORN EWES; PUP GROWTH; GRAY SEALS; GREY SEALS AB 1. Female mammals increase energy expenditure during lactation to support the high cost of milk production. The extent to which lactation in a small phocid species, the Harbour Seal Phoca vitulina L., was fuelled by food vs body stores, how this allocation varied with maternal body mass and the consequences of maternal expenditure on offspring growth were studied. 2. The proportional body composition of 30 females was independent of initial postpartum body mass, but larger females had absolutely more stored energy than smaller ones. 3. Females lost 32% of postpartum body mass and 62% of body energy by late lactation; 97% of energy loss was derived from body fat. Percentage loss of body energy was independent of initial body mass, indicating that females limit their allocation of body stores to offspring by expending a constant proportion of stores rather than a constant amount. 4. Females spent more time diving and individual dives were deeper and longer as lactation progressed. By late lactation, these characteristics of diving were inversely proportional with initial postpartum mass. 5. During early lactation, female expenditures were covered mainly by a reduction in body energy stores. By late lactation, food intake increased six-fold but the extent of this increase varied inversely with postpartum mass. 6. Pup growth rate and weaning mass were positively related to postpartum mass and total daily energy expenditure of females, but were independent of the source of energy used by females during lactation. Pups of heavy females had higher survival than pups of light females. 7. Our results support the hypothesis that maternal body mass is an important determinant of lactation strategies in pinnipeds. C1 Fisheries & Oceans Canada, Bedford Inst Oceanog, Marine Fish Div, Dartmouth, NS B2Y 4A2, Canada. Georgetown Univ, Med Ctr, Div Neonatal Biol, Washington, DC 20008 USA. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Bowen, WD (reprint author), Fisheries & Oceans Canada, Bedford Inst Oceanog, Marine Fish Div, POB 1006, Dartmouth, NS B2Y 4A2, Canada. RI Bowen, William/D-2758-2012 NR 38 TC 82 Z9 85 U1 0 U2 31 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0269-8463 J9 FUNCT ECOL JI Funct. Ecol. PD JUN PY 2001 VL 15 IS 3 BP 325 EP 334 DI 10.1046/j.1365-2435.2001.00530.x PG 10 WC Ecology SC Environmental Sciences & Ecology GA 439RR UT WOS:000169131300006 ER PT J AU Luhr, JF Henry, CD Housh, TB Aranda-Gomez, JJ McIntosh, WC AF Luhr, JF Henry, CD Housh, TB Aranda-Gomez, JJ McIntosh, WC TI Early extension and associated mafic alkalic volcanism from the southern Basin and Range Province: Geology and petrology of the Rodeo and Nazas volcanic fields, Durango, Mexico SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article DE Basin and Range Province; contamination (magma); Durango Mexico; extension faults; hawaiite; Miocene ID LOWER CRUSTAL XENOLITHS; LATE CENOZOIC EXTENSION; TRANS-PECOS TEXAS; RIO-GRANDE RIFT; SAN-LUIS-POTOSI; TRACE-ELEMENTS; ISOTOPIC EVIDENCE; DISTRIBUTION COEFFICIENTS; PARTITION-COEFFICIENTS; BASALTIC VOLCANISM AB East-northeast extension ca, 24 Ma at Rodeo and Nazas, Mexico, was accompanied by eruption of hawaiites, marking some of the earliest intraplate-type mafic alkalic volcanism associated with development of the southern Basin and Range Province. An earlier extensional pulse, 32.3-30.6 Ma, concurrent with subduction-related rhyolitic volcanism of the Sierra Madre Occidental, is the earliest established extension in the southern Basin and Range Province. The Rodeo hawaiites are mostly along or just west of the north-northwest-striking, west-dipping Rodeo fault, a major breakaway fault that separates moderately extended terrane to the west from less extended terrane to the east. Hawaiites and interbedded conglomerates in the Rodeo half graben are flat lying to gently tilted and cut by the Rodeo fault. Underlying Eocene-Oligocene ash-flow tuffs to the west are cut by numerous west-dipping faults and tilted as much as 40 degrees, Nazas hawaiites are also along north-northwest-striking faults but are generally unfaulted, Like other Miocene mafic alkalic volcanic rocks from the southern Basin and Range Province, those from Rodeo and Nazas are characterized by (I) moderately evolved hawaiitic compositions, (2) abundant megacrysts, including sodic plagioclase (An(26-51)), olivine (similar to Fo(55)), Al-augite (7-9 wt% Al2O3), and a wide variety of spinels, (3) lack of granulitic or peridotitic xenoliths, (4) variable Cs enrichments, and (5) isotopic compositions that indicate interaction with crust (Sr-87/Sr-86(i) = 0.7037-0 7041; epsilon (Nd) = 4.8-2.8; Pb-206/Pb-204(i) = 18.91-18.77; Pb-207/Pb-204(i) = 15.57-15.60), These observations are consistent with a model whereby Miocene intraplate-type magmas rose slowly through the lithosphere, differentiating and interacting with the crust, The megacrysts are interpreted as disrupted gabbroic bodies, formed by slow cooling of mafic alkalic magmas that stagnated in the lower crust, possibly during the earlier extensional episode, Many of the elemental and isotopic parameters used to probe mantle sources of mafic volcanic rocks have been seriously obscured by crystallization, crustal interaction, and megacryst incorporation, complicating efforts to identify temporal changes in mantle source regions during development of the southern Basin and Range Province. C1 Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. Univ Nevada, Nevada Bur Mines & Geol, Reno, NV 89557 USA. Univ Texas, Dept Geol Sci, Austin, TX 78712 USA. Univ Nacl Autonoma Mexico, Inst Geol, Unidad Invest Ciencias Tierra, Queretaro 76001, Mexico. New Mexico Bur Mines & Mineral Resources, New Mexico Inst Min & Technol, Socorro, NM 87801 USA. RP Smithsonian Inst, Dept Mineral Sci, NHB-119, Washington, DC 20560 USA. EM luhr@volcano.si.edu; chenry@nbmg.unr.edu; housh@mail.utexas.edu; jjag@servidor.unam.mx; mcintosh@nmt.edu NR 87 TC 21 Z9 22 U1 1 U2 8 PU GEOLOGICAL SOC AMER, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0016-7606 EI 1943-2674 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD JUN PY 2001 VL 113 IS 6 BP 760 EP 773 DI 10.1130/0016-7606(2001)113<0760:EEAAMA>2.0.CO;2 PG 14 WC Geosciences, Multidisciplinary SC Geology GA 438KM UT WOS:000169052300008 ER PT J AU Binzel, RP Harris, AW Bus, SJ Burbine, TH AF Binzel, RP Harris, AW Bus, SJ Burbine, TH TI Spectral properties of near-earth objects: Palomar and IRTF results for 48 objects including spacecraft targets (9969) Braille and (10302) 1989 ML SO ICARUS LA English DT Article DE asteroids; composition; meteorites; surfaces; asteroids ID ORDINARY CHONDRITE METEORITES; MAIN-BELT; ASTEROIDS; DISCOVERY AB We present results of visible wavelength spectroscopic measurements for 48 near-Earth objects (NEOs) obtained with the 5-m telescope at Palomar Mountain Observatory during 1998, 1999, and early 2000. The compositional interpretations for 15 of these objects have been enhanced by the addition of near-infrared spectra obtained with the NASA Infrared Telescope Facility, One-third of our sampled objects fall in the Sq and Q classes and resemble ordinary chondrite meteorites. Overall our sample shows a cleat transition between S-type and Q-type compositional classes over visible and near-infrared wavelengths. Taken together these results point toward an abundance of near-Earth asteroids capable of providing sources for ordinary chondrite meteorites. Our sampling strategy favors targeting the smallest observable objects and we report results for the 15-m diameter object 1998 BT13, the smallest spectroscopically measured NEO to date. NEOs show a greater spectral diversity than main-belt asteroids, and our small sample includes objects falling in the rare categories of K, L, O, and V classes. The K-class object 1999 JD6 is found to match CV chondrite meteorites. Potential spacecraft targets received top priority for observation, with the ordinary chondrite-like composition of (9969) Braille being reported prior to the Deep Space-1 encounter. The relatively accessible asteroid (10302) 1989 ML displays a neutral spectrum that may be interpreted as a shock-darkened ordinary chondrite. (C) 2001 Academic Press. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. RP Binzel, RP (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 20 TC 84 Z9 84 U1 0 U2 5 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2001 VL 151 IS 2 BP 139 EP 149 DI 10.1006/icar.2001.6613 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 441PX UT WOS:000169239700001 ER PT J AU Hacker, BC AF Hacker, BC TI A radar history of World War II: Technical and military imperatives. SO ISIS LA English DT Book Review C1 Smithsonian Natl Museum Amer Hist, Washington, DC 20560 USA. RP Hacker, BC (reprint author), Smithsonian Natl Museum Amer Hist, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0021-1753 J9 ISIS JI Isis PD JUN PY 2001 VL 92 IS 2 BP 419 EP 420 DI 10.1086/385253 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA 476TV UT WOS:000171245600075 ER PT J AU Collins, MJ AF Collins, MJ TI Echoes among the stars: A short history of the US space program. SO JOURNAL OF AMERICAN HISTORY LA English DT Book Review C1 Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. RP Collins, MJ (reprint author), Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ORGANIZATION AMER HISTORIANS PI BLOOMINGTON PA 112 N BRYAN ST, BLOOMINGTON, IN 47408 USA SN 0021-8723 J9 J AM HIST JI J. Am. Hist. PD JUN PY 2001 VL 88 IS 1 BP 300 EP 300 DI 10.2307/2675065 PG 1 WC History SC History GA 441ZD UT WOS:000169258700152 ER PT J AU Stanley, JD Randazzo, G Jorstad, TF AF Stanley, JD Randazzo, G Jorstad, TF TI Iron-stained-quartz as record of recent reworking of older sediment by natural and anthropogenic processes, Rio Grande Delta, Texas SO JOURNAL OF COASTAL RESEARCH LA English DT Article DE cores; dams; Holocene; depositional environments; human activity; irrigation; navigation; Pleistocene; population growth; sediment cut-off; water shortage ID SEA-LEVEL RISE; NILE DELTA; NEW-MEXICO; STRATIGRAPHY; ORIGIN; EGYPT AB The iron-coated quartz grain record in the Rio Grande deltaic plain in southern Texas, determined from petrologic study of surface and core samples, does not show the distribution pattern typically observed in other deltas. The iron-stained grain distribution patterns in this delta are highly irregular in both time and space, and do not display low proportions (< 10%) of coated grains, in surficial and Holocene subsurface deltaic sections versus distinctly higher proportions (to over >20%) of stained grains in underlying Pleistocene alluvial strata. Intermediate (>10%) to large (>20%) amounts of partially plus fully coated quartz particles are measured in most surficial samples of 10 sampled deltaic depositional environments and in Holocene core sections. This is a result of (1) pre-dam fluvial transport of older, iron-stained material from Rio Grande basin areas to the Holocene cover of the delta and its Gulf of Mexico margin, (2) erosion and recent reworking-landward of iron-stained sediment from Rio Grande delta terrains now submerged on the inner and mid-shelf, (3) possible in situ formation of iron-coated grains in the lower valley and delta proper, and (4) intensified post-depositional reworking of the deltaic plain and upper Holocene sections by human activity during the past century. We suggest that anthropogenic activity has now replaced natural processes, especially fluvial transport, as the primary means of mixing older material onto the younger surficial. Rio Grande deltaic plain. The delta's present sediment cover is interpreted as a 'palimpsest' comprising admixtures of reworked modem and relict material, particularly in areas where formerly buried sediment continues to be artificially exposed and modified. We anticipate that the proportion of iron-coated grains will remain high at the Rio Grande deltaic surface as human activity continues to replace natural fluvial transport as the dominant process. C1 Smithsonian Inst, Deltas Global Change Program, Washington, DC 20560 USA. Univ Messina, Dipartimento Sci Terra, I-98166 Messina, Italy. RP Stanley, JD (reprint author), Smithsonian Inst, Deltas Global Change Program, E-206 NMNH, Washington, DC 20560 USA. NR 71 TC 3 Z9 3 U1 0 U2 0 PU COASTAL EDUCATION & RESEARCH FOUNDATION PI LAWRENCE PA 810 EAST 10TH STREET, LAWRENCE, KS 66044 USA SN 0749-0208 J9 J COASTAL RES JI J. Coast. Res. PD SUM PY 2001 VL 17 IS 3 BP 584 EP 598 PG 15 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 479BD UT WOS:000171383300007 ER PT J AU Okazaki, H Stanley, JD Wright, EE AF Okazaki, H Stanley, JD Wright, EE TI Tecolutla and Nautla deltas, Veracruz, Mexico: Texture to evaluate sediment entrapment on deltaic plains and bypassing onto the Gulf of Mexico margin SO JOURNAL OF COASTAL RESEARCH LA English DT Article DE deltas; Gulf of Mexico; lower estuary; mangrove; overbank deposition; selective bypassing; sediment entrapment; size analyses; Veracruz ID BEACH SANDS; OF-MEXICO; PROVENANCE AB This study uses grain-size distributions to contrast sediment transport processes in the Tecolutla and Nautla deltas on the high-energy Veracruz coastal margin, southwestern Gulf of Mexico. Both tropical deltas formed at mouths of short, seasonal high-flood discharge rivers that carry large volcaniclastic loads down steep mountain slopes directly to the coast. Baseline studies of deltaic sediments are needed to help develop protection measures for the increasing delta populations endangered by devastating floods. Eleven environments in each delta are distinguished on the basis of mean size, standard deviation and skewness in surficial sediment samples. These textural parameters are used to interpret transport processes that prevail in the environments of the two deltas. The Tecolutla system discharges more water and carries a greater sediment load than the Nautla. The Tecolutla loses a greater proportion of coarser fractions by overbank transport on its natural levees and flood-plain, and it also traps more finer-grained fractions in its larger marshes, mangroves and upper estuary. Consequently, grains reaching the Tecolutla's lower estuary are of finer mean size and better sorted than those reaching the Nautla's lower estuary. Moreover, a larger proportion of the Tecoluta's sediment load bypasses the lower estuary and is released seaward beyond the river mouth. This conclusion is independently confirmed by the delta's prograding, gentle cuspate form and higher proportions of fluvioclastic light and volcanic mineral components traced from its lower estuary to nearshore settings. In contrast with the Tecolutla, textural evidence suggests erosion and reworking from marine environments and accretion onto the Nautla coast and lower estuary by wave-driven currents. Corroborating evidence is the Nautla's truncated coastal configuration and, in its lower estuary, a masking of the river's volcanic and light minerals by locally concentrated heavy minerals and carbonates. C1 Nat Hist Museum & Inst, Chiba 2608682, Japan. Smithsonian Inst, Deltas Global Change Program, Washington, DC 20560 USA. Coastal Carolina Dept, Dept Marine Sci, Conway, SC 29528 USA. RP Okazaki, H (reprint author), Nat Hist Museum & Inst, Chiba 2608682, Japan. NR 22 TC 5 Z9 5 U1 0 U2 2 PU COASTAL EDUCATION & RESEARCH FOUNDATION PI LAWRENCE PA 810 EAST 10TH STREET, LAWRENCE, KS 66044 USA SN 0749-0208 J9 J COASTAL RES JI J. Coast. Res. PD SUM PY 2001 VL 17 IS 3 BP 755 EP 761 PG 7 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 479BD UT WOS:000171383300023 ER PT J AU Etterson, MA Howery, M AF Etterson, MA Howery, M TI Kleptoparasitism of soil-foraging passerines by Loggerhead Shrikes SO JOURNAL OF FIELD ORNITHOLOGY LA English DT Article AB Loggerhead Shrikes (Lanius ludovicianus) have rarely been observed engaging in kleptoparasitism. We describe two observations of kleptoparasitism by Loggerhead Shrikes on soil-foraging songbirds. We suggest that kleptoparasitism of these birds gives shrikes access to resources that are otherwise unavailable. Kleptoparasitism may help to explain aggressive behavior by shrikes toward birds too large to be depredated successfully. C1 Conservat Biol Program, St Paul, MN 55108 USA. Oklahoma Dept Wildlife Conservat, Oklahoma City, OK 73105 USA. RP Etterson, MA (reprint author), Smithsonian Migratory Bird Ctr, Natl Zool Pk, Washington, DC 20008 USA. NR 12 TC 0 Z9 1 U1 2 U2 2 PU ASSOC FIELD ORNITHOLOGISTS PI STATESBORO PA GEORGIA SOUTHERN UNIV, DEPT BIOLOGY, STATESBORO, GA 30460-8042 USA SN 0273-8570 J9 J FIELD ORNITHOL JI J. Field Ornithol. PD SUM PY 2001 VL 72 IS 3 BP 458 EP 461 PG 4 WC Ornithology SC Zoology GA 455VP UT WOS:000170048700015 ER PT J AU Li, X Habbal, SR AF Li, X Habbal, SR TI Damping of fast and ion cyclotron oblique waves in the multi-ion fast solar wind SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CORONAL HOLES; ALFVEN WAVES; RESONANT ACCELERATION; TRANSITION REGION; VELOCITY SHEAR; HEAVY-IONS; TURBULENCE; DRIVEN; MODEL; DISSIPATION AB A detailed linear analysis of the behavior of oblique fast waves in a multi-ion low-beta Vlasov plasma such as the solar wind is presented. It is shown that at very oblique propagation angles, proton fundamental and second harmonic cyclotron damping become dominant. The property of oblique fast waves can also be significantly changed in the presence of minor ions. Depending on their abundance and relative speed with respect to protons, minor ions can change the wave polarization from right-handed at small wave numbers to left-handed at larger wave numbers for some propagation angles. Consequently, a power law spectrum of oblique fast waves originating at the Sun may preferentially heat and accelerate alpha particles rather than protons and electrons in the fast solar wind. Furthermore, it is shown that oblique fast waves can heat minds ions more than oblique Alfvenic ion cyclotron waves thus making them a potentially more important candidate for the preferential heating of minor ions in the solar wind than ion cyclotron waves. C1 Univ Coll Wales, Dept Phys, Aberystwyth SY23 3BZ, Dyfed, Wales. Smithsonian Astrophys Observ, Cambridge, MA USA. RP Li, X (reprint author), Univ Coll Wales, Dept Phys, Aberystwyth SY23 3BZ, Dyfed, Wales. NR 44 TC 34 Z9 34 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 JUN 1 PY 2001 VL 106 IS A6 BP 10669 EP 10680 DI 10.1029/2000JA000420 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 435WP UT WOS:000168905400017 ER PT J AU Wachowiak, M AF Wachowiak, M TI American Windsor chairs SO JOURNAL OF THE AMERICAN INSTITUTE FOR CONSERVATION LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Wachowiak, M (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CONSERVATION HISTORIC ARTISTIC WORKS PI WASHINGTON PA 1717 K ST, NW, STE 301, WASHINGTON, DC 20006 USA SN 0197-1360 J9 J AM INST CONSERV JI J. Am. Inst. Conserv. PD SUM PY 2001 VL 40 IS 2 BP 168 EP 170 PG 3 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA 592EF UT WOS:000177923200017 ER PT J AU Hall, JPW AF Hall, JPW TI A revision of the new riodinid butterfly genus Dachetola (Lepidoptera : Riodinidae) SO JOURNAL OF THE NEW YORK ENTOMOLOGICAL SOCIETY LA English DT Article DE Calospila; Chalodeta; Metacharis; neotropical; Nymphidiini; Riodinini AB The new riodinid genus Dachetola, tribe Riodinini, is described and illustrated from Central and South America. Four species are recognized: azora Godart. [1824], and virido Lathy, 1958, are transferred from Chalodeta Stichel to Dachetola (comb. novs.), and caligata Stichel, 1911, and pione Bates, 1868, are transferred from Calospila Geyer to Dachetola (comb. novs.). Dachetola is hypothesized to be most closely related to Metacharis Butler. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol Entomol, Washington, DC 20560 USA. RP Hall, JPW (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol Entomol, Washington, DC 20560 USA. NR 17 TC 5 Z9 6 U1 0 U2 0 PU NEW YORK ENTOMOLOGICAL SOC INC PI NEW YORK PA C/O AMER MUSEUM NAT HIST 79TH & CENTRAL PARK WEST, NEW YORK, NY 10024 USA SN 0028-7199 J9 J NEW YORK ENTOMOL S JI J. N.Y. Entomol. Soc. PD SUM PY 2001 VL 109 IS 2 BP 183 EP 195 DI 10.1664/0028-7199(2001)109[0183:AROTNR]2.0.CO;2 PG 13 WC Entomology SC Entomology GA 467GC UT WOS:000170693200001 ER PT J AU Hall, JPW Harvey, DJ AF Hall, JPW Harvey, DJ TI A reassessment of Calociasma with the description of a new genus and a new species (Lepidoptera : Riodinidae : Nymphidiini) SO JOURNAL OF THE NEW YORK ENTOMOLOGICAL SOCIETY LA English DT Article DE Calociasma; cladistics; genitalia; morphology AB The genus Calociasma appears to be polyphyletic and contains members that belong to all three currently recognized subtribes of the Nymphidiini. Only the type species, ictericum, and laius are retained in Calociasma, which belongs to the subtribe Nymphidiina. The taxa pulcherrima, comparata and felicis are removed to Juditha (n. combs.) in the Lemoniadina. and lilina (n. comb.) and its newly described sister species from Panama, robbinsi n. sp., are placed in the new genus Calicosama n. gen. in the Theopeina. Calicosama is characterized. and its biology and systematic position discussed. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Syst Biol Entomol, Washington, DC 20560 USA. RP Hall, JPW (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Syst Biol Entomol, Washington, DC 20560 USA. NR 18 TC 1 Z9 3 U1 0 U2 0 PU NEW YORK ENTOMOLOGICAL SOC INC PI NEW YORK PA C/O AMER MUSEUM NAT HIST 79TH & CENTRAL PARK WEST, NEW YORK, NY 10024 USA SN 0028-7199 J9 J NEW YORK ENTOMOL S JI J. N.Y. Entomol. Soc. PD SUM PY 2001 VL 109 IS 2 BP 196 EP 205 DI 10.1664/0028-7199(2001)109[0196:AROCWT]2.0.CO;2 PG 10 WC Entomology SC Entomology GA 467GC UT WOS:000170693200002 ER PT J AU Polhemus, DA AF Polhemus, DA TI A review of the genus Ptilomera (Heteroptera : Gerridae) in Indochina, with descriptions of two new species SO JOURNAL OF THE NEW YORK ENTOMOLOGICAL SOCIETY LA English DT Review DE Heteroptera; Gerridae; Indochina; new species; distribution AB The water strider species of the genus Ptilomera occurring in Indochina are reviewed. and two new species are described and figured; P. fang from northern Thailand, and P. burmana from northern Burma. Keys to species for both males and females are provided for all taxa found in the region, accompanied by detailed distributional records and range maps. C1 Smithsonian Inst, Dept Entomol, MRC 105, Washington, DC 20560 USA. RP Polhemus, DA (reprint author), Smithsonian Inst, Dept Entomol, MRC 105, Washington, DC 20560 USA. NR 4 TC 4 Z9 6 U1 0 U2 0 PU NEW YORK ENTOMOLOGICAL SOC INC PI NEW YORK PA C/O AMER MUSEUM NAT HIST 79TH & CENTRAL PARK WEST, NEW YORK, NY 10024 USA SN 0028-7199 J9 J NEW YORK ENTOMOL S JI J. N.Y. Entomol. Soc. PD SUM PY 2001 VL 109 IS 2 BP 214 EP 234 DI 10.1664/0028-7199(2001)109[0214:AROTGP]2.0.CO;2 PG 21 WC Entomology SC Entomology GA 467GC UT WOS:000170693200004 ER PT J AU Mawdsley, JR AF Mawdsley, JR TI Mitochondrial cytochrome oxidase I DNA sequences and the phylogeny of Coccinellidae (Insecta : Coleoptera : Cucujoidea) SO JOURNAL OF THE NEW YORK ENTOMOLOGICAL SOCIETY LA English DT Article AB A recently-published phylogenetic tree, constructed using the neighbor-joining algorithm,summarized relationships among 37 species of Coleoptera (Insecta) indicated by a 400 base pair region of the mitochondrial cytochrome oxidase I gene. Ibis study included sequences from four species of the family Coccinellidae, The relationships of the four coccinellids indicated by the published neighbor-joining tree are congruent with current hypotheses of their relationships based on adult, larval, and pupal morphology. However, re-analysis of the molecular sequences for these taxa using standard parsimony methods reveals a more complex situation in which the use of different outgroups and different tree-searching algorithms yields strikingly different topologies. many of which do not correspond to the pattern of relationships derived from morphological data. These sequences may simply be too variable and too highly convergent to accurately reflect the phylogenetic history of Coccinellidae. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, MRC 187, Washington, DC 20560 USA. RP Mawdsley, JR (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, MRC 187, Washington, DC 20560 USA. NR 13 TC 0 Z9 0 U1 1 U2 6 PU NEW YORK ENTOMOLOGICAL SOC INC PI NEW YORK PA C/O AMER MUSEUM NAT HIST 79TH & CENTRAL PARK WEST, NEW YORK, NY 10024 USA SN 0028-7199 J9 J NEW YORK ENTOMOL S JI J. N.Y. Entomol. Soc. PD SUM PY 2001 VL 109 IS 2 BP 304 EP 308 DI 10.1664/0028-7199(2001)109[0304:MCOIDS]2.0.CO;2 PG 5 WC Entomology SC Entomology GA 467GC UT WOS:000170693200008 ER PT J AU Grobler, D Bush, M Jessup, D Lance, W AF Grobler, D Bush, M Jessup, D Lance, W TI Anaesthesia of gemsbok (Oryx gazella) with a combination of A3080, medetomidine and ketamine SO JOURNAL OF THE SOUTH AFRICAN VETERINARY ASSOCIATION-TYDSKRIF VAN DIE SUID-AFRIKAANSE VETERINERE VERENIGING LA English DT Article DE A3080; anaesthesia; atipamezole; gemsbok; ketamine; medetomidine; naltrexone; Oryx gazella; oxygen saturation ID IMMOBILIZATION; ATIPAMEZOLE; LEUCORYX AB An effective anaesthesia protocol was developed for adult free-ranging gemsbok (Oryx gazella) using a combination of A3080, medetomidine and ketamine. A short induction time; good muscle relaxation, adequate oxygenation and stable heart rate and respiration rate characterised this anaesthetic regime. Equal doses of A3080 and medetomidine (22-45 mug/kg) plus 300 mg of ketamine were administered to each animal. The anaesthesia was rapidly and completely reversed by intramuscular naltrexone at a dose of (X) over bar = 0.9 +/- 0.2 mg/kg and a tipamezole at a dose (K) over bar +/- 90 +/- 20 mug/kg. No mortality or morbidity occurred with this protocol. C1 Kruger Natl Pk, ZA-1350 Shukuza, South Africa. Natl Zool Pk, Conservat & Res Ctr, Front Royal, VA USA. Dept Fish & Game, Santa Cruz, CA USA. Wildlife Pharmaceut, Ft Collins, CO USA. RP Grobler, D (reprint author), Kruger Natl Pk, Private Bag X402, ZA-1350 Shukuza, South Africa. NR 18 TC 13 Z9 15 U1 0 U2 1 PU SOUTH AFRICAN VET ASSN PI MONUMENT PARK PA PO BOX 25033, MONUMENT PARK 0105, SOUTH AFRICA SN 0038-2809 J9 J S AFR VET ASSOC JI J. S. Afr. Vet. Assoc.-Tydskr. Suid-Afr. Vet. Ver. PD JUN PY 2001 VL 72 IS 2 BP 81 EP 83 PG 3 WC Veterinary Sciences SC Veterinary Sciences GA 454KC UT WOS:000169970900007 PM 11513265 ER PT J AU Kalfatovic, MR AF Kalfatovic, MR TI Einstein, Picasso: Space, time and the beauty that causes havoc. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC USA. RP Kalfatovic, MR (reprint author), Smithsonian Inst Lib, Washington, DC USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD JUN 1 PY 2001 VL 126 IS 10 BP 154 EP 154 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 440AF UT WOS:000169150200057 ER PT J AU Burbine, TH Buchanan, PC Binzel, RP Bus, SJ Hiroi, T Hinrichs, JL Meibom, A McCoy, TJ AF Burbine, TH Buchanan, PC Binzel, RP Bus, SJ Hiroi, T Hinrichs, JL Meibom, A McCoy, TJ TI Vesta, Vestoids, and the howardite, eucrite, diogenite group: Relationships and the origin of spectral differences SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID ASTEROID 4 VESTA; MAIN-BELT; PARENT BODY; METEORITES; PYROXENE; SURFACE; EVOLUTION; BODIES; SIZE; CHONDRITES AB Spectra of asteroid 4 Vesta and 21 small (estimated diameters less than 10 km) asteroids with Vesta-like spectral properties (Vestoids) were measured at visible and near-infrared wavelengths (similar to0.44 to similar to1.65 mum). All of the measured small asteroids (except for 2579 Spartacus) have reflectance spectra consistent with surface compositions similar to eucrites and howardites and consistent with all being derived from Vesta. None of the observed asteroids have spectra similar to diogenites. We find no spectral distinction between the 15 objects tabulated as members of the Vesta dynamical family and 6 of the 7 sampled "non-family" members that reside just outside the semi-major axis (a), eccentricity (e), and inclination (i) region of the family. The spectral consistency and close orbital (a-e-i) match of these "non-family" objects to Vesta and the Vesta family imply that the true bounds of the family extend beyond the subjective cut-off for membership. Asteroid 2579 Spartacus has a spectrum consistent with a mixture of eucritic material and olivine. Spartacus could contain olivine-rich material from Vesta's mantle or may be unrelated to Vesta altogether. Laboratory measurements of the spectra of eucrites show that samples having nearly identical compositions can display a wide range of spectral slopes. Finer particle sizes lead to an increase in the slope, which is usually referred to as reddening. This range of spectral variation for the best-known meteoritic analogs to the Vestoids, regardless of whether they are actually related to each other, suggests that the extremely red spectral slopes for some Vestoids can be explained by very fine-grained eucritic material on their surfaces. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Univ Hawaii Manoa, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. RP Burbine, TH (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. NR 74 TC 114 Z9 115 U1 0 U2 6 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUN PY 2001 VL 36 IS 6 BP 761 EP 781 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 454VD UT WOS:000169991700002 ER PT J AU Perdices, A Doadrio, I AF Perdices, A Doadrio, I TI The molecular systematics and biogeography of the European cobitids based on mitochondrial DNA sequences SO MOLECULAR PHYLOGENETICS AND EVOLUTION LA English DT Article DE ATP synthase 8 and 6; Cobitidae; cytochrome b; phylogenetics; secondary sexual dimorphism ID POPULATIONS; XIPHOPHORUS; EVOLUTION; PHYLOGENY; CLOCK AB Phylogenetic inference regarding the biogeography and evolution of the family Cobitidae depends in large part on the correct interpretation of transitions between the morphological states of secondary sexual characters (e.g., the scale of Canestrini or lamina circularis). Here, we use the complete mitochondrial ATP synthase 8 and 6 and cytochrome b genes to provide an independent assessment of systematics and biogeographic relationships of species in the genus Cobitis, including geographic and subgeneric sampling of species with Canestrini's scale present, duplicated, or absent. The mtDNA-based phylogeny for the genus Cobitis provides the first formal hypothesis for the group and permits a phylogenetic-based assessment of the morphological transitions demonstrated by Canestrini's scale. Our data confirm the monophyly of the genus Cobitis and indicate that European Cobitis comprise six evolutionarily independent lineages. These lineages were defined by nucleotide synapomorphies permitting bootstrapped confidence estimates of 95% or greater and mtDNA genetic distances greater than 4.5% and correspond with moderate fidelity to the Cobitis groups defined by Bacescu (1962, Rev. Roum. Biol. 4, 435-448). The Caucasian lineage, C. cf: sibirica, represents the basal sister species of the genus Cobitis, supporting an eastern Asiatic origin of the European Cobitis: Cobitis sensu stricto, Acanestrinia, Bicanestrinia, Iberocobitis, and Cobitis calderoni. Phylogenetic relationships among Cobitis subgenera and species indicate that the ancestral condition of one scale of Canestrini was duplicated once at the origin of the Bicanestrinia lineage and has been in dependently lost by C. calderoni and C. elongata. The absence of the scale of Canestrini is the synapomorphy defining the subgenus Acanestrinia, but the mtDNA phylogeny indicates that Acanestrinia is not a natural group and places C. calderoni as the sister lineage to the subgenus Iberocobitis, a finding that is also geographically parsimonius. (C) 2001 Academic Press. C1 CSIC, Museo Nacl Ciencias Nat, E-28006 Madrid, Spain. Smithsonian Trop Res Inst, Balboa, Ancon, Panama. RP Perdices, A (reprint author), CSIC, Museo Nacl Ciencias Nat, Jose Gutierrez Abascal 2, E-28006 Madrid, Spain. OI Doadrio, Ignacio/0000-0003-4863-9711 NR 44 TC 85 Z9 95 U1 1 U2 12 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1055-7903 J9 MOL PHYLOGENET EVOL JI Mol. Phylogenet. Evol. PD JUN PY 2001 VL 19 IS 3 BP 468 EP 478 DI 10.1006/mpev.2000.0900 PG 11 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 441PA UT WOS:000169237700010 PM 11399153 ER PT J AU Balog, Z Delgado, AJ Moitinho, A Furesz, G Kaszas, G Vinko, J Alfaro, EJ AF Balog, Z Delgado, AJ Moitinho, A Furesz, G Kaszas, G Vinko, J Alfaro, EJ TI Fundamental parameters and new variables of the galactic open cluster NGC 7128 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE techniques : photometric; techniques : spectroscopic; stars : variables : other; open clusters and associations : individual : NGC 7128 ID DIFFUSE INTERSTELLAR BANDS; UVBY-BETA-PHOTOMETRY; MAIN-SEQUENCE STARS; SPECTRAL CLASSIFICATION; STROMGREN PHOTOMETRY; SOUTHERN CLUSTERS; B-STARS; CALIBRATIONS; MAGNITUDE; CEPHEIDS AB CCD photometry in Johnson UBV and Stromgren uvby systems and medium-resolution spectroscopy of the galactic open cluster NGC 7128 are presented. Spectral types of the brightest 12 stars in the cluster field were determined based on equivalent widths of the Hac and the HeI 6678-Angstrom line. The spectroscopic observations also revealed two obvious and one probable Be-type stars showing H alpha emission. The analysis of the photometric diagrams gave a colour excess of E(B - V) = 1.03 +/- 0.06 mag, a distance modulus DM = 13.0 +/- 0.2 mag and an age above 10 Myr. Time-resolved photometric observations obtained on one night resulted in the detection of short time-scale light variations of seven new and three already known variable stars in the cluster field. C1 Univ Szeged, Dept Opt & Quantum Elect, H-6720 Szeged, Hungary. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CSIC, Inst Astrofis Andalucia, Granada, Spain. Univ Nacl Autonoma Mexico, Inst Astron, Ensenada 22800, BC, Mexico. Univ Szeged, Dept Expt Phys, H-6720 Szeged, Hungary. RP Balog, Z (reprint author), Univ Szeged, Dept Opt & Quantum Elect, Dom Ter 9, H-6720 Szeged, Hungary. EM zbalog@cfa.harvard.edu RI Moitinho de Almeida, Andre/L-1624-2015; OI Moitinho de Almeida, Andre/0000-0003-0822-5995; Alfaro, E. J./0000-0002-2234-7035; Vinko, Jozsef/0000-0001-8764-7832 NR 49 TC 4 Z9 4 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUN 1 PY 2001 VL 323 IS 4 BP 872 EP 886 DI 10.1046/j.1365-8711.2001.04280.x PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 443QN UT WOS:000169352000008 ER PT J AU Mathur, S Kuraszkiewicz, J Czerny, B AF Mathur, S Kuraszkiewicz, J Czerny, B TI Evolution of active galaxies: black-hole mass-bulge relations for narrow line objects SO NEW ASTRONOMY LA English DT Article DE galaxies : active; galaxies : evolution; quasars : general; galaxies : Seyfert ID X-RAY-PROPERTIES; SEYFERT-1 GALAXIES; GALACTIC NUCLEI; VELOCITY DISPERSION; ASCA OBSERVATIONS; EMISSION-LINES; QUASARS; SPECTRA; MODELS; KINEMATICS AB Mathur [MNRAS Letters 314 (2000) L17] has proposed that the narrow line Seyfert 1 galaxies (NLS1s) are likely to be the active galaxies in the early stage of evolution. To test this hypothesis, we have calculated the black hole (BH) masses and the host galaxy bulge masses for a sample of NLS1s. We find that the mean BH to bulge mass ratio of NLS1s is significantly smaller than that for normal Seyfert galaxies. We also find that the ratio of BH mass to bulge velocity dispersion is also significantly smaller for NLS1s. A scenario of BH growth is our preferred interpretation, though alternative explanations are discussed. Assuming that the BHs grow with accretion with a radiative efficiency of 0.1, it will take them t greater than or similar to 3.3 x 10(8) years to become as massive as in normal Seyfert 1s. These timescales are consistent with the theoretical estimates of quasar timescale t(Q) less than or similar to 4.5 x 10(8) years calculated by Haehnelt et al. [MNRAS 300 (1998) 817]. Studies of low redshift NLS1s thus provide a powerful, and due to their proximity, relatively easy way to understand the high redshift quasars and their evolution. (C) 2001 Elsevier Science B. V. All rights reserved. C1 Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. N Copernicus Astron Ctr, Warsaw, Poland. RP Mathur, S (reprint author), Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RI Czerny, Bozena/A-2363-2015 OI Czerny, Bozena/0000-0001-5848-4333 NR 50 TC 94 Z9 94 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1384-1092 J9 NEW ASTRON JI New Astron. PD JUN PY 2001 VL 6 IS 5 BP 321 EP 329 DI 10.1016/S1384-1076(01)00058-6 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 449XV UT WOS:000169713200005 ER PT J AU Strong, MT AF Strong, MT TI Novelties in Rhynchospora (Cyperaceae) from the Guianas SO NOVON LA English DT Article DE Cyperaceae; Guianas; Rhynchospora; South America AB Five new species are described (R. angustipaniculata, R. ayangannensis, R. bakhuisensis, R. donselaarii, and R. rupicola) and a new name proposed (R. pubisquama) in Rhynchospora Vahl nom. cons. from northeastern South America (Guianas). Illustrations are provided for the new species, their classification is determined, and a discussion of related species is given for each. C1 Smithsonian Inst, Dept Systemat Biol, MRC 166, Washington, DC 20560 USA. RP Strong, MT (reprint author), Smithsonian Inst, Dept Systemat Biol, MRC 166, 10th & Constitut Ave, Washington, DC 20560 USA. NR 6 TC 2 Z9 3 U1 0 U2 0 PU MISSOURI BOTANICAL GARDEN PI ST LOUIS PA 2345 TOWER GROVE AVENUE, ST LOUIS, MO 63110 USA SN 1055-3177 J9 NOVON JI Novon PD SUM PY 2001 VL 11 IS 2 BP 261 EP 273 DI 10.2307/3393065 PG 13 WC Plant Sciences SC Plant Sciences GA 451YJ UT WOS:000169830100014 ER PT J AU Hunt, G Chapman, RE AF Hunt, G Chapman, RE TI Evaluating hypotheses of instar-grouping in arthropods: a maximum likelihood approach SO PALEOBIOLOGY LA English DT Article ID MARINE FOSSIL RECORD; POPULATION BIOLOGY; COPEPOD GROWTH; DYAR RULE; TRILOBITE; ONTOGENY; SIZE; HETEROCHRONY; CIRRIPEDIA; ALGORITHM AB The ontogeny of arthropod exoskeletons is punctuated by short periods of growth following each molt, separated by longer stages of unchanging morphology called instars. The recognition of instar clusters in size distributions has been important in understanding the growth and evolution of fossil arthropods. Generally, these clusters have been identified by inspection, but this approach has been criticized for its subjectivity. In this paper, we describe a statistical framework for evaluating hypotheses of clustering based on maximum likelihood analysis of mixture models. The approach assumes that individuals are normally distributed within instars; thus an arthropod size distribution can be considered a mixture of normal distributions. This methodology provides an objective framework to compare various plausible hypotheses of grouping, including the possibility that there is no significant grouping at all. We apply this method to evaluate clustering in two trilobite species, Ampyxina bellatula and Piochaspis sellata. Both of these data sets show statistically significant evidence of clustering, a phenomenon rarely documented for holaspid-stage trilobites. After consideration of alternative causes of clustering, we argue that the observed groupings are best explained as instar groups. In these two species, growth increments between molts were similar throughout the observed portion of ontogeny, although subtle yet significant variation can be seen within the ontogeny of Ampyxina bellatula. C1 Univ Chicago, Comm Evolutionary Biol, Chicago, IL 60637 USA. Smithsonian Inst, Natl Museum Amer Hist, Appl Morphometr Lab, ADP,NHB,MRC 136, Washington, DC 20560 USA. RP Univ Chicago, Comm Evolutionary Biol, Chicago, IL 60637 USA. EM eg-hunt@uchicago.edu; Chapman.Ralph@NMNH.SI.EDU RI Hunt, Gene/B-3783-2010 OI Hunt, Gene/0000-0001-6430-5020 NR 72 TC 29 Z9 31 U1 0 U2 3 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0094-8373 EI 1938-5331 J9 PALEOBIOLOGY JI Paleobiology PD SUM PY 2001 VL 27 IS 3 BP 466 EP 484 DI 10.1666/0094-8373(2001)027<0466:EHOIGI>2.0.CO;2 PG 19 WC Biodiversity Conservation; Ecology; Evolutionary Biology; Paleontology SC Biodiversity & Conservation; Environmental Sciences & Ecology; Evolutionary Biology; Paleontology GA 537NY UT WOS:000174766200004 ER PT J AU Wing, SL Harrington, GJ AF Wing, SL Harrington, GJ TI Floral response to rapid warming in the earliest Eocene and implications for concurrent faunal change SO PALEOBIOLOGY LA English DT Review ID PALEOCENE THERMAL MAXIMUM; BIGHORN BASIN; LATEST PALEOCENE; NORTH-AMERICA; WILLWOOD FORMATION; TERTIARY; PLANT; EVOLUTION; HEMISPHERE; FOREST AB During the first 10-20 Kyr of the Eocene temperatures warmed by 4-8degreesC in middle and high latitudes, then cooled again over the succeeding similar to200 Kyr. Major changes in the composition of marine and terrestrial faunas, including one of the largest mammalian turnover events of the Cenozoic, occurred during this temperature excursion. To better understand the effects of rapid climatic change on continental biotas, we studied 60 fossil pollen samples collected from 900 m of section spanning approximately three million years of the late Paleocene and early Eocene; the samples come from the Fort Union Formation and Willwood Formation in the Bighorn Basin of northwestern Wyoming, paleolatitude approximately 47degreesN. There are 40 samples from the 500 m of rock deposited during the one million year interval centered on the Paleocene/Eocene boundary, although pollen was not preserved well in rocks representing the short warm interval at the base of the Eocene. Overall, the palynoflora shows moderate change in composition and diversity. Two pollen taxa clearly expanded their ranges to include North America in the first 400 Kyr of the Eocene, Platycarya (Juglandaceae), and Intratriporopollenites instructus (cf. Tilia), but they account for less than 5% of pollen grains in the early Eocene. There are no last appearances of common taxa associated with the Paleocene/Eocene boundary. The most noticeable palynological changes are the decrease in abundance of Caryapollenites spp. and Polyatriopollenites vermontensis (Juglandaceae), and the increase in abundance of Taxodiaceae (bald cypress family), Ulmaceae (elm family), and Betulaceae (birch family), particularly Alnipollenites spp, (alder). There are 22% more species in the Eocene samples than in the Paleocene samples; mean richness of Eocene samples is 17% higher than the mean of Paleocene samples. The mean evenness of Eocene samples is higher than that of Paleocene samples, but the difference is not significant. The modest level of floral change during the late Paleocene and early Eocene contrasts with the major taxonomic turnover and ecological rearrangement of North American mammalian faunas observed at the same time. Faunal change probably resulted from intercontinental range expansion across Arctic land bridges that became habitable as a result of high-latitude warming, so it is surprising that climatically sensitive plants did not also experience a major episode of interchange. The absence of fossil plants from the temperature excursion interval itself could prevent us from recognizing a transient shift in floral composition, but it is clear that the flora did not undergo a major and permanent restructuring like that seen in the mammals. The contrast between the moderate floral response to warming and the strong faunal response is consistent with the idea that interactions between immigrant and native taxa, rather than climate directly, were the primary cause of terrestrial biotic change across the Paleocene/Eocene boundary. C1 Smithsonian Inst, Dept Paleobiol, MRC121, Washington, DC 20560 USA. Univ Sheffield, Dept Anim & Plant Sci, Ctr Palynol, Sheffield S10 2TN, S Yorkshire, England. RP Wing, SL (reprint author), Smithsonian Inst, Dept Paleobiol, MRC121, Washington, DC 20560 USA. OI Wing, Scott/0000-0002-2954-8905 NR 103 TC 61 Z9 66 U1 0 U2 18 PU PALEONTOLOGICAL SOC INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0094-8373 J9 PALEOBIOLOGY JI Paleobiology PD SUM PY 2001 VL 27 IS 3 BP 539 EP 563 DI 10.1666/0094-8373(2001)027<0539:FRTRWI>2.0.CO;2 PG 25 WC Biodiversity Conservation; Ecology; Evolutionary Biology; Paleontology SC Biodiversity & Conservation; Environmental Sciences & Ecology; Evolutionary Biology; Paleontology GA 537NY UT WOS:000174766200009 ER PT J AU Phillips, DF Humphrey, MA Mattison, EM Stoner, RE Vessot, RFC Walsworth, RL AF Phillips, DF Humphrey, MA Mattison, EM Stoner, RE Vessot, RFC Walsworth, RL TI Limit on Lorentz and CPT violation of the proton using a hydrogen maser SO PHYSICAL REVIEW D LA English DT Article ID HIGHER-DIMENSIONAL THEORIES; STANDARD MODEL; STRINGS; INVARIANCE; CONSTRAINTS; ANISOTROPY; PARTICLES; ELECTRON; SYMMETRY; SHIFT AB We present a new measurement constraining Lorentz and CPT violation of the proton using a hydrogen maser double resonance technique. A search for hydrogen Zeeman frequency variations with a period of the sidereal day (23.93 h) sets a limit on violation of Lorentz and CPT symmetry of the proton at the 10(-27) GeV level, independent of nuclear model uncertainty, which improves significantly on previous bounds. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Phillips, DF (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 42 TC 162 Z9 162 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2001 VL 63 IS 11 AR 111101 DI 10.1103/PhysRevD.63.111101 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 438AM UT WOS:000169031600001 ER PT J AU Watters, TR Konopliv, AS AF Watters, TR Konopliv, AS TI The topography and gravity of Mare Serenitatis: implications for subsidence of the mare surface SO PLANETARY AND SPACE SCIENCE LA English DT Article ID WRINKLE RIDGES; CLEMENTINE MISSION; LUNAR; MOON; ORIGIN; BASINS; EVOLUTION; TECTONICS; ALTIMETRY; RADAR AB The long wavelength topography of Mare Serenitatis was analyzed using topographic data obtained by the Clementine laser ranging instrument (LIDAR). The topography shows that the lowest elevations in the mare surface occur near the margins of the basin. The present mare surface reflects a long period of volcanism, subsidence, and deformation. Subsidence is generally attributed to a Gaussian-shaped, superisostatic load from the mare basalts that results in flexure of the lunar lithosphere. Gravity data from Lunar Prospector suggest that the basalt sequence in the interior of Serenitatis is generally uniform in thickness and thins rapidly at the margins. This suggests that the topographic lows in the basin do not coincide with areas where the mare basalts are thick but rather occur where the basalts thin. The topographic lows also do not appear to coincide with accumulations of the youngest mare basalt units. The long wavelength topography of Mare Serenitatis may reflect subsidence influenced by pre-mare basalt basin topography and preexisting zones of lithospheric weakness. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, Washington, DC 20560 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Watters, TR (reprint author), Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, Washington, DC 20560 USA. NR 51 TC 9 Z9 10 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUN PY 2001 VL 49 IS 7 BP 743 EP 748 DI 10.1016/S0032-0633(01)00007-1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 441CT UT WOS:000169214000006 ER PT J AU Finn, BS AF Finn, BS TI Lincoln Electric: A history SO PUBLIC HISTORIAN LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Finn, BS (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CALIF PRESS PI BERKELEY PA C/O JOURNALS DIVISION, 2000 CENTER ST, STE 303, BERKELEY, CA 94704-1223 USA SN 0272-3433 J9 PUBL HISTORIAN JI Public Hist. PD SUM PY 2001 VL 23 IS 3 BP 97 EP 100 PG 4 WC History SC History GA 470UR UT WOS:000170890000014 ER PT J AU Finn, BS AF Finn, BS TI Manufacturing the future: A history of Western Electric SO PUBLIC HISTORIAN LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Finn, BS (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CALIF PRESS PI BERKELEY PA C/O JOURNALS DIVISION, 2000 CENTER ST, STE 303, BERKELEY, CA 94704-1223 USA SN 0272-3433 J9 PUBL HISTORIAN JI Public Hist. PD SUM PY 2001 VL 23 IS 3 BP 97 EP 100 PG 4 WC History SC History GA 470UR UT WOS:000170890000013 ER PT J AU Mueller, UG Schultz, TR Currie, CR Adams, RMM Malloch, D AF Mueller, UG Schultz, TR Currie, CR Adams, RMM Malloch, D TI The origin of the attine ant-fungus mutualism SO QUARTERLY REVIEW OF BIOLOGY LA English DT Review ID ACROMYRMEX-OCTOSPINOSUS REICH; LEAF-CUTTING ANTS; ARBUSCULAR MYCORRHIZAL FUNGI; MYCOPHAGOUS FLY COMMUNITIES; SOLENOPSIS-INVICTA BUREN; ATTA COLOMBICA TONSIPES; IMPORTED FIRE ANT; GROWING ANTS; PHYLOGENETIC-RELATIONSHIPS; LITTER INVERTEBRATES AB Cultivation of fungus for food originated about 45-65 million years ago in the ancestor of fungus-growing ants (Formicidae, tribe Attini), representing an evolutionary transition from the life of a hunter-gatherer of anthropod prey, nectar, and other plant juices, to the life of a farmer subsisting on cultivated fungi. Seven hypotheses have been suggested for the origin of attine fungiculture, each differing with respect to the substrate used by the ancestral attine ants for fungal cultivation. Phylogenetic information on the cultivated fungi, in conjunction with information on the nesting biology of extant attine ants and their presumed closest relatives, reveal that the attine ancestors probably did not encounter their cultivars-to-be in seed stores (von Ihering 1894), in rotting wood (Forel 1902), as mycorrhizae (Garling 1979), an arthropod corpses (von Ihering 1894) or ant faeces in nest middens (Wheeler 1907). Rather, the attine ant-fungus mutualism probably arose from adventitious interactions with fungi that grew on walls of nests built in leaf litter (Emery 1899), or from a system of fungal myrmecochory in which specialized fungi relied on ants for dispersal (Bailey 1920) and in which the ants fortuitously vectored these fungi from parent to offspring nests prior to a true fungicultural stage. Reliance on fungi as a dominant food source has evolved only twice in ants: first in the attine ants, and second in some ant species in the solenopsidine genus Megalomyrmex that either coexist as trophic parasites in gardens of attine hosts or aggressively usurp gardens from them. All other known ant-fungus associations are either adventitious or have nonnutritional functions (e.g. strengthening of carton-walls in ant nests). There exist no unambiguous reports of facultative mycophagy in ants, but such trophic ant-fungus interactions would most likely occur underground or in leaf litter and thus escape easy observation. Indirect evidence of fungivory can be deduced from contents of the ant alimentary canal and particularly from the contents of the infrabuccal pocket, a pharyngeal device that filters out solids before liquids pass into the intestine. Infrabuccal pocket contents reveal that ants routinely ingest fungal spores and hyphal material. Infrabuccal contents are eventually expelled as a pellet on nest middens or away from the nest by foragers, suggesting that the pellet provides fungi with a means for the dispersal of spores and hyphae. Associations between such "buccophilous" fungi and ants may have originated multiple times and may have become elaborated and externalized in the case of the attine ant-fungus mutualism. Thus, contrary to the traditional model in which attine fungi are viewed as passive symbionts that happened to come under ant control, this alternative model of a myrmecochorous origin of the attine mutualism attributes an important role to evolutionary modifications of the fungi that preceded the ant transition from hunter-gatherer to fungus farmer. C1 Univ Texas, Patterson Labs, Sect Integrat Biol, Austin, TX 78712 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, Washington, DC 20560 USA. Univ Toronto, Dept Bot, Toronto, ON M5S 3B2, Canada. RP Mueller, UG (reprint author), Univ Texas, Patterson Labs, Sect Integrat Biol, Austin, TX 78712 USA. EM umueller@mail.utexas.edu RI Adams, Rachelle/J-8846-2013 OI Adams, Rachelle/0000-0002-0918-9861 NR 212 TC 156 Z9 164 U1 14 U2 85 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0033-5770 J9 Q REV BIOL JI Q. Rev. Biol. PD JUN PY 2001 VL 76 IS 2 BP 169 EP 197 DI 10.1086/393867 PG 29 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 437PN UT WOS:000169002900002 PM 11409051 ER PT J AU Harding, DJ Lefsky, MA Parker, GG Blair, JB AF Harding, DJ Lefsky, MA Parker, GG Blair, JB TI Laser altimeter canopy height profiles - Methods and validation for closed-canopy, broadleaf forests SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE laser; altimeter; forest; canopy; structure; height; broadleaf; lidar; altimetry; waveform; SLICER ID LEAF-AREA INDEX; RADAR BACKSCATTER; AIRBORNE LIDAR; SAR INTERFEROMETRY; DECIDUOUS FORESTS; WAVE-FORMS; VEGETATION; BIOMASS; TOPOGRAPHY; MODEL AB Waveform-recording laser altimeter observations of vegetated landscapes provide a time-resolved measure of laser pulse backscatter energy from canopy surfaces and the underlying ground. Airborne laser altimeter waveform data was acquired using the Scanning Lidar Imager of Canopies by Echo Recovery (SLICER) for a successional sequence of four, closed-canopy, deciduous forest stands in eastern Maryland. The four stands were selected so as to include a range of canopy structures of importance to forest ecosystem function, including variation in the height and roughness of the outermost canopy surface and the vertical organization of canopy stories and gaps. The character of the SLICER backscatter signal is described and a method is developed that accounts for occlusion of the laser energy by canopy surfaces, transforming the backscatter signal to a canopy height profile (CHP) that quantitatively represents the relative vertical distribution of canopy surface area. The transformation applies increased weighting to the backscatter amplitude as a function of closure through the canopy and assumes a horizontally random distribution of the canopy components. SLICER CHPs, averaged over areas of overlap where altimeter ground tracks intersect, are shown to be highly reproducible. CHP transects across the four stands reveal spatial variations in vegetation, at the scale of the individual 10-m-diameter laser footprints, within and between stands. Averaged SLICER CHPs are compared to analogous height profile results derived from ground-based sightings to plant intercepts measured on plots within the four stands. The plots were located on the segments of the altimeter ground tracks from which averaged SLICER CHPs were derived, and the ground observations were acquired within 2 weeks of the SLICER data acquisition to minimize temporal change. The differences in canopy structure between the four stands is similarly described by the SLICER and ground-based CHP results. However, a chi-square test of similarity documents differences that are statistically significant. The differences are discussed in terms of measurement properties that define the smoothness of the resulting CHPs and canopy properties that may vertically bias the CHP representations of canopy structure. The statistical differences are most likely due to the more noisy character of the ground-based CHPs, especially high in the canopy where ground-based sightings are rare resulting in an underestimate of canopy surface area and height, and to departures from assumptions of canopy uniformity, particularly regarding lack of clumping and vertically constant canopy reflectance, which bias the CHPs. The results demonstrate that the SLICER observations reliably provide a measure of canopy structure that reveals ecologically interesting structural variations such as those characterizing a successional sequence of closed-canopy, broadleaf forest stands. (C) 2001 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. US Forest Serv, USDA, Forest Sci Lab, Pacific NW Res Stn, Corvallis, OR 97331 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Harding, DJ (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Mail Code 924, Greenbelt, MD 20771 USA. RI Lefsky, Michael/A-7224-2009; Blair, James/D-3881-2013; Beckley, Matthew/D-4547-2013; Harding, David/F-5913-2012; OI Parker, Geoffrey/0000-0001-7055-6491 NR 55 TC 225 Z9 240 U1 6 U2 47 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUN PY 2001 VL 76 IS 3 BP 283 EP 297 DI 10.1016/S0034-4257(00)00210-8 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 439FL UT WOS:000169100100001 ER PT J AU Parker, GG Lefsky, MA Harding, DJ AF Parker, GG Lefsky, MA Harding, DJ TI Light transmittance in forest canopies determined using airborne laser altimetry and in-canopy quantum measurements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID OPTICAL-PROPERTIES; DECIDUOUS FORESTS; VEGETATION; LIDAR; TERRESTRIAL; TOPOGRAPHY; MARYLAND; BIOMASS; VOLUME; STANDS AB The vertical distribution of light transmittance was derived from field and laser altimeter observations taken in the same canopies of five forests of several ages (young to mature) and canopy types (eastern broadleaved and western tall conifer). Vertical transmittances were derived remotely from the Scanning Lidar Imager of Canopies by Echo Recovery (SLICER) laser altimeter and in the field from measurements of Photosynthetically Active Radiation (PAR) made within the canopy using quantum sensors suspended from the gondola of a tower crane or atop small balloons. Derived numerical characteristics of mean transmittance profiles (the rate of attenuation, whole canopy transmittance, and the radiation-effective height) were similar for both methods across the sites. Measures of the variance and skewness of transmittance also showed similar patterns far corresponding heights between methods. The two methods exhibited greater correspondence in the eastern stands than in the western ones; differences in the interaction between canopy organization and the sensor characteristics between the stand types might explain this. The narrower, more isolated crowns of the western stands permit a deeper penetration into the canopy of nadir-directed laser light than of direct solar radiation from typical elevation angles. Transects of light transmittance in two stands demonstrate that the SLICER sensor can capture meaningful functional variation. Additionally, for one stand with numerous overlapping transects we constructed a three-dimensional View of the transmittance field. Using geostatistics, we demonstrated that the spatial covariance measured in the horizontal plane varied as a function of height. These results suggest a means to remotely assess an important functional characteristic of vegetation, providing a capacity for process-based ecological studies at large scales. (C) 2001 Elsevier Science Inc. All rights reserved. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. Pacific NW Expt Stn, Corvallis, OR 97331 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Parker, GG (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. RI Lefsky, Michael/A-7224-2009; Harding, David/F-5913-2012; OI Parker, Geoffrey/0000-0001-7055-6491 NR 55 TC 60 Z9 64 U1 3 U2 21 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUN PY 2001 VL 76 IS 3 BP 298 EP 309 DI 10.1016/S0034-4257(00)00211-X PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 439FL UT WOS:000169100100002 ER PT J AU Neale, PJ Fritz, JJ Davis, RF AF Neale, PJ Fritz, JJ Davis, RF TI Effects of UV on photosynthesis of Antarctic phytoplankton: models and their application to coastal and pelagic assemblages SO REVISTA CHILENA DE HISTORIA NATURAL LA English DT Article; Proceedings Paper CT Mini Symposium on Photobiology CY 1999 CL PUERTO VARAS, CHILE DE Southern Ocean; primary productivity; ozone depletion; photosynthesis-irradiance curves; biological weighting functions ID ULTRAVIOLET-B RADIATION; MARINE-PHYTOPLANKTON; CARBON UPTAKE; INHIBITION; SPECTRA; DIATOM AB We have characterized the photosynthetic response to ultraviolet radiation (UV) of natural phytoplankton assemblages in Antarctic (Southern Ocean) waters, Biological weighting functions (BWFs) and exposure response curves for inhibition of photosynthesis by UV were measured during spring-time ozone depletion (October-November). Two different models were developed to relate photosynthesis to UV exposure. A model that is a function of the duration of exposure (BWFH) applied to assemblages in the well-mixed open waters of the Weddell-Scotia Confluence (WSC, 60 degrees S, 50 degrees W), since responses were a function of cumulative exposure and recovery rates were slow. These assemblages had a variable but generally high sensitivity to UV. A steady-state model (BWFE) applied in the shallow waters near the Antarctic Peninsula (Palmer Station, 64 degrees S, 64 degrees W), where inhibition was a function of irradiance (reciprocity failed), and recovery was rapid. Using information on the time-dependence of photosynthesis in assemblages with active repair. inferences were drawn on the relative contribution of damage and recovery processes to the UV weights. BWFs for Palmer phytoplankton sampled during periods of pack-ice cover had both higher damage and higher repair than BWFs for WSC assemblages. BWFs for Palmer phytoplankton sampled during open water periods had about the same damage weights as Weddell-Scotia assemblages but had a higher repair rate. Solar exposures of more than 10 min were predicted to have generally less effect on Palmer phytoplankton than the WSC phytoplankton. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Neale, PJ (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. RI Neale, Patrick/A-3683-2012 NR 27 TC 11 Z9 11 U1 0 U2 2 PU SOCIEDAD BIOLGIA CHILE PI SANTIAGO PA CASILLA 16164, SANTIAGO 9, CHILE SN 0716-078X J9 REV CHIL HIST NAT JI Rev. Chil. Hist. Nat. PD JUN PY 2001 VL 74 IS 2 BP 283 EP 292 PG 10 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 458DM UT WOS:000170178000006 ER PT J AU Laurance, WF Fearnside, PM Cochrane, MA D'Angelo, S Bergen, S Delamonica, P AF Laurance, WF Fearnside, PM Cochrane, MA D'Angelo, S Bergen, S Delamonica, P TI Development of the Brazilian Amazon - Response SO SCIENCE LA English DT Letter ID DAM C1 Smithsonian Trop Res Inst, Balboa, Panama. Natl Inst Amazonian Res INPA, Dept Ecol, BR-69011970 Manaus, Amazonas, Brazil. Natl Inst Amazonian Res INPA, Biol Dynam Forest Fragments Project, BR-69011970 Manaus, Amazonas, Brazil. Oregon State Univ, Dept Forest Sci, Corvallis, OR 97331 USA. Michigan State Univ, E Lansing, MI 48823 USA. RP Laurance, WF (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. RI Laurance, William/B-2709-2012; Fearnside, Philip/D-6559-2011 OI Fearnside, Philip/0000-0003-3672-9082 NR 11 TC 12 Z9 14 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 1 PY 2001 VL 292 IS 5522 BP 1652 EP 1654 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 438AP UT WOS:000169031800019 ER PT J AU Verhoeven, JTA Whigham, DF van Logtestijn, R O'Neill, J AF Verhoeven, JTA Whigham, DF van Logtestijn, R O'Neill, J TI A comparative study of nitrogen and phosphorus cycling in tidal and non-tidal riverine wetlands SO WETLANDS LA English DT Article DE The Netherlands; Maryland; Belgium; riverine; tidal; non-tidal; wetlands; vegetation; mineralization; denitrification; geographic comparison; decomposition ID FRESH-WATER MARSH; NUTRIENT DYNAMICS; CHESAPEAKE BAY; DISCHARGES; SOIL; ECOLOGY; PLANT AB This paper describes a study of nutrient dynamics in 17 tidal and non-tidal freshwater riverine wetlands in The Netherlands, Belgium, and Maryland (USA). The purpose of the study was to investigate the relationships between nutrient cycling processes in riverine wetlands that were geographically separated, that were dominated by different types of vegetation, and that had different hydrodynamics We also compared restored and natural riverine wetlands. The results showed distinct differences in interstitial water chemistry between the sites in Maryland and Europe. No such regional differences were found in the soil variables, except for soil phosphorus, which was higher in The Netherlands. Soil organic matte, total nitrogen and phosphorus content, and bulk density were higher in tidal freshwater wetland soils. Forested wetland soils had higher organic matter and total nitrogen and lower bulk density and total phosphorus than soils from wetlands dominated by herbaceous species. Restored wetlands had lower soil organic matter and total soil nitrogen and phosphorus than similar types of natural riverine wetlands. There were no differences in nutrient-related process rates nor plant nutrient concentrations in tidal versus non-tidal riverine wetlands. Lower nitrogen and phosphorus concentrations in plants at the restored sites suggest that nutrient uptake by vegetation may be poorly coupled to rates of nutrient cycling during early stages of vegetation development. A principal components analysis of the data identified groupings of soil and water variables that were similar to those that had been previously identified when we applied the same methods to peatlands that were also geographically widely separated. Results of the study demonstrate that the techniques that we have been using are robust and repeatable. They are especially useful for making general comparisons of nitrogen and phosphorus cycling when there are limitations on the number of wetland that can be sampled. The approach that we have developed may also be used to calibrate and refine nutrient cycling models that are incorporated into wetland assessment procedures. C1 Univ Utrecht, Dept Geobiol, Sect Landscape Ecol, NL-3508 TB Utrecht, Netherlands. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Verhoeven, JTA (reprint author), Univ Utrecht, Dept Geobiol, Sect Landscape Ecol, POB 800-84, NL-3508 TB Utrecht, Netherlands. RI van Logtestijn, Richardus/B-9680-2009; Verhoeven, Jos/B-9514-2011; OI Whigham, Dennis/0000-0003-1488-820X NR 35 TC 29 Z9 39 U1 1 U2 30 PU SOC WETLAND SCIENTISTS PI LAWRENCE PA 810 E TENTH ST, P O BOX 1897, LAWRENCE, KS 66044 USA SN 0277-5212 J9 WETLANDS JI Wetlands PD JUN PY 2001 VL 21 IS 2 BP 210 EP 222 DI 10.1672/0277-5212(2001)021[0210:ACSONA]2.0.CO;2 PG 13 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 444RG UT WOS:000169412900005 ER PT J AU Isler, ML Alonso, JA Isler, PR Whitney, BM AF Isler, ML Alonso, JA Isler, PR Whitney, BM TI A new species of Percnostola antbird (Passeriformes : Thamnophilidae) from Amazonian Peru, and an analysis of species limits within Percnostola rufifrons SO WILSON BULLETIN LA English DT Article ID BIRD COMMUNITY; FOREST; AVES AB Ornithological studies undertaken in certain sandy soil habitats of lowland northeastern Peru uncovered a previously undescribed species of Perenostola antbird. Elements of its morphology, vocalizations, ;and behavior indicate that it should be considered a well-differentiated species, closely related to P. rufifrons. We present a description of the new species' an analysis of how it differs from the four previously described subspecies of P. rufifrons: and a reconsideration of species limits within P. rufifrons, employing measures of morphology, vocalizations, and behavior. Under guidelines developed previously (Isler et al, 1998, 1999), vocal differences among the four subspecies (rufifrons, suberistata, minor, and jensoni) of P. rufifrons were insufficient to support considering them distinct species. However, differences in morphology among most of the four taxa were substantial, and we look forward to genetic studies of Perenostola and related groups. The localized and highly specialized habitat preferences of the new species cause grave concern for its conservation. C1 Smithsonian Inst, Natl Museum Nat Hist, Div Birds, Washington, DC 20560 USA. Inst Invest Amazonia Peru, Iquitos, Peru. Louisiana State Univ, Museum Nat Sci, Baton Rouge, LA 70803 USA. RP Isler, ML (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Div Birds, Washington, DC 20560 USA. NR 26 TC 19 Z9 20 U1 0 U2 3 PU WILSON ORNITHOLOGICAL SOC PI ANN ARBOR PA MUSEUM OF ZOOLOGY UNIV MICHIGAN, ANN ARBOR, MI 48109 USA SN 0043-5643 J9 WILSON BULL JI Wilson Bull. PD JUN PY 2001 VL 113 IS 2 BP 164 EP 176 DI 10.1676/0043-5643(2001)113[0164:ANSOPA]2.0.CO;2 PG 13 WC Ornithology SC Zoology GA 525DN UT WOS:000174053600004 ER PT J AU Bayer, FM AF Bayer, FM TI New species of Calyptrophora (Coelenterata : Octocorallia : Primnoidae) from the western part of the Atlantic Ocean SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Three new species of the gorgonacean genus Calyptrophora from the western Atlantic are described and compared with the previously known C. trilepis (Pourtales, 1868). All are illustrated by scanning electron micrographs. The status of several Indo-Pacific specimens indentified in the literature as the type species, C. japonica Gray, 1866, is discussed, and a new drawing of Gray's specimen is provided. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Bayer, FM (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 25 TC 8 Z9 12 U1 1 U2 1 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 367 EP 380 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200003 ER PT J AU McLaughlin, PA Lemaitre, R AF McLaughlin, PA Lemaitre, R TI Revision of Pylopagurus and Tomopagurus (Crustacea : Decapoda : Paguridae), with descriptions of new genera and species. Part VI. Pylopagurus A Milne-Edwards & Bouvier, 1891, Haigia McLaughlin, 1981, and Pylopaguridium, a new genus SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID ANOMURA; PACIFIC AB In this final part of a six-part series, two new species of Pylopagurus A. Milne-Edwards & Bouvier are described, P. macgeorgei and P. gorei, and one existing species, P. longicarpus Walton, is placed in synonymy with P. holmesi Schmitt. Some species of Pylopagurus have been found to exhibit weak development of a male sexual tube, thus requiring emendation of the generic diagnosis. A new monotypic genus, Pylopaguridium, is proposed for a new species, P. markhami, in which males have asymmetrical coxae of the fifth pereopods. The monotypic Pacific genus Haigia McLaughlin, is reviewed. An amended key to all the genera of the "Pylopagurus-Tomopagurus" group, and a key to the species now assigned to Pylopagurus are included. All species of Pylopagurus, Pylopaguridium, and Haigia are diagnosed or described and illustrated, and their morphological variations discussed. C1 Western Washington Univ, Shannon Point Marine Ctr, Anacortes, WA 98221 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Lemaitre, R (reprint author), Western Washington Univ, Shannon Point Marine Ctr, 1900 Shannon Point Rd, Anacortes, WA 98221 USA. NR 43 TC 15 Z9 17 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 444 EP 483 PG 40 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200011 ER PT J AU Kensley, B Hickman, CP AF Kensley, B Hickman, CP TI A new species of Calaxius Sakai & de Saint Laurent, 1989, from the Galapagos Islands (Crustacea : Decapoda : Axiidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Calaxius galapagensis, a new species, is described on the basis of two ovigerous females from coral rubble in shallow water at North Plaza off Isla Santa Cruz, Galapagos Islands. The species is compared with the eight previously described species of Calaxius Sakai & de Saint Laurent, 1989, and characterized by a strongly tridentate rostral apex, and by rows of corneous spine-like setae on pereopods 3 and 4. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. Washington & Lee Univ, Dept Biol, Lexington, VA 24450 USA. RP Hickman, CP (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 14 TC 5 Z9 6 U1 1 U2 1 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 484 EP 488 PG 5 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200012 ER PT J AU Johnson, GD Seeto, J Rosenblatt, RH AF Johnson, GD Seeto, J Rosenblatt, RH TI Parmops echinatus, a new species of flashlight fish (Beryciformes : Anomalopidae) from Fiji SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID SOUTH-PACIFIC; GENUS AB A second species of the genus Parmops is described from two specimens collected in 440m and 550m respectively in Fiji. Parmops echinatus n.sp. is distinguished most prominently from P. coruscans in lacking midventral scutes and an external tooth parch on the lateral face of the dentary, and in having papillose ridges on the gular isthmus, 15 dorsal-fin soft rays, 12 anal-fin soft rays, 15 or 16 pectoral-fins rays, 34 pored lateral-line scales and 14 + 17 vertebrae. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. Univ S Pacific, Marine Studies Programme, Suva, Fiji. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Johnson, GD (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 5 TC 4 Z9 4 U1 5 U2 5 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 497 EP 500 PG 4 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200014 ER PT J AU Suarez, W Olson, SL AF Suarez, W Olson, SL TI Further characterization of Caracara creightoni Brodkorb based on fossils from the Quaternary of Cuba (Aves : Falconidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Caracara creightoni, previously known from three fragmentary fossils from New Providence Island, Bahamas, is here documented from two Quaternary sites in Cuba. It appears to have been a smaller species than C. cheriway, but with a more robust bill and quadrate and other cranial differences, relatively shorter wings, and more robust hindlimb elements. The Living species C. cheriway appears to be a relatively recent arrival in Cuba so that it is Likely that fossils of Caracara from the West Indies may all belong to extinct endemic species. C1 Museo Nacl Hist Nat, CH-10100 La Habana, Cuba. Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Suarez, W (reprint author), Museo Nacl Hist Nat, Obispo 61,Plaza Armas, CH-10100 La Habana, Cuba. NR 11 TC 10 Z9 10 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 501 EP 508 PG 8 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200015 ER PT J AU Olson, SL Wingate, DB AF Olson, SL Wingate, DB TI A new species of large flightless rail of the Rallus longirostris/elegans complex (Aves : Rallidae) from the late Pleistocene of Bermuda SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Rallus recessus, new species, probably derived from the King Rail R. elegans, is described from a cave deposit exposed in quarrying operations on the island of Bermuda. This species had the reduced elements of the wing and pectoral girdle and more robust hindlimbs typical of flightless rails. It is the only member of the largest: size-class of the genus Rallus known to have colonized an oceanic island and become flightless. It was present on Bermuda during the last (Wisconsinan) glacial period and appears to have become extinct naturally due to changing environmental conditions associated with changes in sea level. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. Bermuda Nat Hist Museum, Flatts, Bermuda. RP Olson, SL (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 6 TC 19 Z9 19 U1 2 U2 4 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 509 EP 516 PG 8 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200016 ER PT J AU Lucas, SG Emry, RJ AF Lucas, SG Emry, RJ TI Sharamynodon (Mammalia : Perissodactyla) from the Eocene of the Ily basin, Kazakstan and the antiquity of Asian amynodonts SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB The brontothere bone bed at Kyzyl Murun near Aktau Mountain in the Ily basin of eastern Kazakstan is a 0.5-m-thick layer of green bentonitic mudstone in the Kyzylbulak Formation that yields numerous skeletons of the middle Eocene (Irdinmanhan) brontothere Protitan. An incomplete skull, lower jaw and some fragmentary postcrania from this bed belong to an amynodontid rhinoceros. This specimen can be assigned to Sharamynodon mongoliensis (Osborn) because it displays numerous diagnostic features of that taxon, including three closely spaced incisors, a short nasal incision that extends back to the postcanine diastema, a deep and tall preorbital fossa, and a relatively short preorbital portion of the skull. This is the first record of Sharamynodon from Kazakstan and the oldest Kazak amynodontid. Previous reports of this taxon indicate it had a broad geographic (China, Mongolia, Japan) and temporal (Irdinmanhan-Ergilian, i.e., middle-latest Eocene) distribution in Asia. There is no evidence that any Asian amynodont record is older than Irdinmanhan. Thus, we consider the record of "Andarakodon" from Andarak, Kyrgyzstan to be Irdinmanhan, not older. Indeed, "Andarakodon" is a junior subjective synonym of Sharamynodon. C1 New Mexico Museum Nat Hist, Albuquerque, NM 87104 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. RP Lucas, SG (reprint author), New Mexico Museum Nat Hist, 1801 Mountain rd NW, Albuquerque, NM 87104 USA. NR 26 TC 4 Z9 7 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 517 EP 525 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200017 ER PT J AU Robinson, H AF Robinson, H TI A new species of Ageratina from Chiapas, Mexico (Eupatorieae : Asteraceae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Ageratina (Neogreenella) resinifera is described as: new based on a Breedlove collection from Chiapas, Mexico, having glabrous leaves with internal resiniferous lenses. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Robinson, H (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 526 EP 528 PG 3 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200018 ER PT J AU Robinson, H AF Robinson, H TI New species of Fleischmannia from Panama and Andean South America (Asteraceae : Eupatorieae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Fifteen species of Fleischmannia are named as new, F. hammelii from Panama, F. killipii and F. narinoensis from Colombia, F. ceronii, F. dodsonii, F. kingii, F. microsternoides, and F. zakii from Ecuador, and F. altihuanucana, F. cajamarcensis, F. davidsmithii, F. petiolata, F. quirozii, F. sagasteguii, and F, vargasii from Peru. Distinctions of other Colombian, Ecuadorian and Peruvian species are discussed. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Robinson, H (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD MAY 25 PY 2001 VL 114 IS 2 BP 529 EP 556 PG 28 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 438RK UT WOS:000169067200019 ER PT J AU Cairns, SD AF Cairns, SD TI Corals of the world SO SCIENCE LA English DT Book Review C1 Natl Museum Nat Hist, Smithsonian Inst, Dept Systemat Biol Invertebrate Zool, Washington, DC 20560 USA. RP Cairns, SD (reprint author), Natl Museum Nat Hist, Smithsonian Inst, Dept Systemat Biol Invertebrate Zool, Washington, DC 20560 USA. NR 1 TC 0 Z9 2 U1 2 U2 7 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 25 PY 2001 VL 292 IS 5521 BP 1492 EP 1492 DI 10.1126/science.1061936 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 436YQ UT WOS:000168963800026 ER PT J AU Knowlton, N AF Knowlton, N TI Ecology - Coral reef biodiversity - Habitat size matters SO SCIENCE LA English DT Editorial Material ID SPECIES RICHNESS; DESTRUCTION; PATTERNS C1 Univ Calif San Diego, Scripps Inst Oceanog, Div Marine Biol Res, La Jolla, CA 92093 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Knowlton, N (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Div Marine Biol Res, La Jolla, CA 92093 USA. NR 17 TC 15 Z9 20 U1 4 U2 27 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 MAY 25 PY 2001 VL 292 IS 5521 BP 1493 EP + DI 10.1126/science.1061690 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 436YQ UT WOS:000168963800027 PM 11379628 ER PT J AU Krebs, E AF Krebs, E TI Borges and the tango (Response to Anthony Howell's assumptions concerning tango lore) SO TLS-THE TIMES LITERARY SUPPLEMENT LA English DT Letter C1 Smithsonian Inst, Dept Anthropol, Washington, DC 20560 USA. RP Krebs, E (reprint author), Smithsonian Inst, Dept Anthropol, Washington, DC 20560 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU TIMES SUPPLEMENTS LIMITED PI MARKET HARBOROUGH PA TOWER HOUSE, SOVEREIGN PARK, MARKET HARBOROUGH LE87 4JJ, ENGLAND SN 0307-661X EI 1366-7211 J9 TLS-TIMES LIT SUPPL JI TLS-Times Lit. Suppl. PD MAY 25 PY 2001 IS 5121 BP 17 EP 17 PG 1 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA 440VN UT WOS:000169195800021 ER PT J AU Wilf, P Labandeira, CC Johnson, KR Coley, PD Cutter, AD AF Wilf, P Labandeira, CC Johnson, KR Coley, PD Cutter, AD TI Insect herbivory, plant defense, and early Cenozoic climate change SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ADAPTIVE SIGNIFICANCE; DECIDUOUS FOREST; TROPICAL FORESTS; LEAF; EOCENE; FOLIAGE; SURVIVORSHIP; CONVERGENCE; COMMUNITIES; EVOLUTION AB Insect damage on fossil leaves from the Central Rocky Mountains, United States, documents the response of herbivores to changing regional climates and vegetation during the late Paleocene (humid. warm temperate to subtropical, predominantly deciduous). early Eocene (humid subtropical, mixed deciduous and evergreen), and middle Eocene (seasonally dry, subtropical, mixed deciduous and thick-leaved evergreen). During all three time periods, greater herbivory occurred on taxa considered to have shout rather than long leaf life spans, consistent with studies in living forests that demonstrate the insect resistance of long-lived, thick leaves. Variance in herbivory frequency and diversity was highest during the middle Eocene, indicating the increased representation of two distinct herbivory syndromes: one for taxa with deciduous, palatable foliage, and the other for hosts with evergreen, thick-textured, small leaves characterized by elevated insect resistance. Leaf galling, which is negatively correlated with moisture today, apparently increased during the middle Eocene, whereas leaf mining decreased. C1 Univ Michigan, Museum Paleontol, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Geol Sci, Ann Arbor, MI 48109 USA. Smithsonian Inst, Dept Paleobiol, Natl Museum Nat Hist, Washington, DC 20560 USA. Univ Maryland, Dept Entomol, College Pk, MD 20742 USA. Denver Museum Nat & Sci, Dept Earth & Space Sci, Denver, CO 80205 USA. Univ Utah, Dept Biol, Salt Lake City, UT 84112 USA. Univ Arizona, Dept Ecol & Evolutionary Biol, Tucson, AZ 85721 USA. RP Wilf, P (reprint author), Univ Michigan, Museum Paleontol, 1109 Geddes Rd, Ann Arbor, MI 48109 USA. RI Cutter, Asher/A-5647-2009 NR 64 TC 76 Z9 79 U1 1 U2 32 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 MAY 22 PY 2001 VL 98 IS 11 BP 6221 EP 6226 DI 10.1073/pnas.111069498 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 435LV UT WOS:000168883700052 PM 11353840 ER PT J AU Currie, CR Stuart, AE AF Currie, CR Stuart, AE TI Weeding and grooming of pathogens in agriculture by ants SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE behaviour; Escovopsis; fungus-growing ants; mutualism; pathogens; symbiosis ID FUNGUS-GROWING ANTS; SYMBIOSIS AB The ancient mutualism between fungus-growing ants and the fungi they cultivate for food is a textbook example of symbiosis. Fungus-growing ants' ability to cultivate fungi depends on protection of the garden from the aggressive microbes associated with the substrate added to the garden as well as from the specialized virulent garden parasite Escovopsis. Mie examined ants' ability to remove alien microbes physically by infecting Atta colombica gardens with the generalist pathogen Trichoderma viride and the specialist pathogen Escovopsis. The ants sanitized the garden using two main behaviours: grooming of alien spores from the garden (fungus grooming) and removal of infected garden substrate (weeding). Unlike previously described hygienic behaviours (e.g. licking and self-grooming), fungus-grooming and garden-removal behaviours are specific responses to the presence of fungal pathogens. In the presence of pathogens, they are the primary activities performed by workers, but they are uncommon in uninfected gardens. In fact, workers rapidly eliminate Trichoderma from their gardens by fungus grooming and weeding, suggesting that these behaviours are the primary method of garden defence against generalist pathogens. The same sanitary behaviours were performed in response to the presence of the specialist pathogen Escovopsis. However, the intensity and duration of these behaviours were much greater in this treatment. Despite the increased effort, the ants were unable to eliminate Escovopsis from their gardens, suggesting that this specialized pathogen has evolved counter-adaptations in order to overcome the sanitary defences of the ants. C1 Univ Toronto, Dept Bot, Toronto, ON M5S 3B2, Canada. Smithsonian Trop Res Inst, Balboa, Panama. Univ Texas, Sect Integrat Biol, Austin, TX 78712 USA. Univ Toronto, Dept Zool, Toronto, ON M5S 1A2, Canada. RP Currie, CR (reprint author), Univ Toronto, Dept Bot, 25 Willcocks St, Toronto, ON M5S 3B2, Canada. EM ccurrie@mail.utexas.edu NR 27 TC 150 Z9 156 U1 1 U2 48 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8452 J9 P ROY SOC B-BIOL SCI JI Proc. R. Soc. B-Biol. Sci. PD MAY 22 PY 2001 VL 268 IS 1471 BP 1033 EP 1039 PG 7 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA 435TB UT WOS:000168896300007 PM 11375087 ER PT J AU Silverman, JD Eriksen, KA Green, PJ Saar, SH AF Silverman, JD Eriksen, KA Green, PJ Saar, SH TI Extensive serendipitous X-ray coverage of a flare star with ROSAT SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars : flare; stars : late-type; X-rays : stars ID SOLAR NEIGHBORHOOD; STELLAR FLARES; DWARF STARS; EMISSION; ALGOL AB We report the serendipitous discovery of a flare star observed with the ROSAT X-ray observatory. From optical spectra, which show strong and variable emission Lines of the hydrogen Balmer series and neutral helium, we classify this object as a M3.0Ve star, and estimate a distance of 52 pc from published photometry. Owing to the close proximity of the star (13.6 arcmin) to the calibration source and RS CVn binary AR Lacertae, long-term X-ray coverage is available in the ROSAT archive (similar to 50 h spanning 6.5 yr). Two large flare events occurred early in the mission (1990 June-July), and the end of a third flare was detected in 1996 June. One flare, observed with the Position Sensitive Proportional Counter (PSPC), had a peak luminosity L-X = 1.1 x 10(30) erg s(-1), an e-folding rise time of 2.2 h and a decay time of 7 h. This decay time is one of the longest detected on a dMe star, providing evidence for the possibility of additional heating during the decay phase. A large High Resolution Imager (HRI) flare (peak L-X = 2.9 x 10(30) erg s(-1)) is also studied. The 'background' X-ray emission is also variable-evidence for low-level flaring or microflaring. We find that greater than or equal to 59 per cent of the HRI counts and greater than or equal to 68 per cent of the PSPC counts are caused by flares. At least 41 per cent of the HRI exposure time and 47 per cent of the PSPC are affected by detectable flare enhancement. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Silverman, JD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 20 TC 1 Z9 1 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 21 PY 2001 VL 323 IS 3 BP 577 EP 583 DI 10.1046/j.1365-8711.2001.04148.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 441KN UT WOS:000169229700006 ER PT J AU Freedman, WL Madore, BF Gibson, BK Ferrarese, L Kelson, DD Sakai, S Mould, JR Kennicutt, RC Ford, HC Graham, JA Huchra, JP Hughes, SMG Illingworth, GD Macri, LM Stetson, PB AF Freedman, WL Madore, BF Gibson, BK Ferrarese, L Kelson, DD Sakai, S Mould, JR Kennicutt, RC Ford, HC Graham, JA Huchra, JP Hughes, SMG Illingworth, GD Macri, LM Stetson, PB TI Final results from the Hubble Space Telescope key project to measure the Hubble constant SO ASTROPHYSICAL JOURNAL LA English DT Review DE cepheids; cosmology : observations; distance scale; galaxies : distances and redshifts ID EXTRAGALACTIC DISTANCE SCALE; TULLY-FISHER RELATION; GRAVITATIONAL LENSING EXPERIMENT; MICROWAVE BACKGROUND-RADIATION; EXPANDING PHOTOSPHERE METHOD; CHARGE-TRANSFER EFFICIENCY; PERIOD-LUMINOSITY RELATION; VELOCITY-WIDTH RELATION; LARGE-MAGELLANIC-CLOUD; BVRI CCD PHOTOMETRY AB We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised distances, and give the implications of these results for cosmology. Our results are based on a Cepheid calibration of several secondary distance methods applied over the range of about 60-400 Mpc. The analysis presented here benefits from a number of recent improvements and refinements, including (1) a larger LMC Cepheid sample to define the fiducial period-luminosity (PL) relations, (2) a more recent HST Wide Field and Planetary Camera 2 (WFPC2) photometric calibration, (3) a correction for Cepheid metallicity, and (4) a correction for incompleteness bias in the observed Cepheid PL samples. We adopt a distance modulus to the LMC (relative to which the more distant galaxies are measured) of mu (o)(LMC) = 18.50 +/- 0.10 mag, or 50 kpc. New, revised distances are given for the 18 spiral galaxies for which Cepheids have been discovered as part of the Key Project, as well as for 13 additional galaxies with published Cepheid data. The new calibration results in a Cepheid distance to NGC 4258 in better agreement with the maser distance to this galaxy. Based on these revised Cepheid distances, we find values (in km s(-1) Mpc(-1)) of H-o = 71 +/- 2 (random) +/- 6 (systematic) (Type Ia supernovae), H-o = 71 +/- 3 +/- 7 (Tully-Fisher relation), H-o = 70 +/- 5 +/- 6 (surface brightness fluctuations), H-o = 72 +/- 9 +/- 7 (Type II supernovae), and H-o = 82 +/- 6 +/- 9 (fundamental plane). We combine these results for the different methods with three different weighting schemes, and find good agreement and consistency with H-o = 72 +/- 8 km s(-1) Mpc(-1). Finally, we compare these results with other, global methods for measuring H-o. C1 Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. CALTECH, NASA IPAC Extragalact Database, Pasadena, CA 91125 USA. Swinburne Univ Technol, Ctr Astrophys & Supercomp, Hawthorn, Vic 3122, Australia. Rutgers State Univ, Piscataway, NJ 08854 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. RP Freedman, WL (reprint author), Carnegie Inst Washington Observ, 813 Santa Barbara St, Pasadena, CA 91101 USA. RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 165 TC 2122 Z9 2131 U1 3 U2 37 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 MAY 20 PY 2001 VL 553 IS 1 BP 47 EP 72 DI 10.1086/320638 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JA UT WOS:000169280400006 ER PT J AU Padoan, P Juvela, M Goodman, AA Nordlund, A AF Padoan, P Juvela, M Goodman, AA Nordlund, A TI The turbulent shock origin of proto-stellar cores SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (Perseus, Rosette, Taurus); ISM : kinematics and dynamics; radio lines : ISM; turbulence ID FILAMENTARY MOLECULAR CLOUDS; LTE RADIATIVE-TRANSFER; STAR-FORMING REGIONS; INTERSTELLAR CLOUDS; MAGNETIC-FIELDS; DARK CLOUDS; SUPERSONIC TURBULENCE; MAGNETOHYDRODYNAMIC TURBULENCE; GRAVITATIONAL COLLAPSE; HIERARCHICAL STRUCTURE AB The fragmentation of molecular clouds (MC) into proto-stellar cores is a central aspect of the process of star formation. Because of the turbulent nature of supersonic motions in MCs, it has been suggested that dense structures such as filaments and clumps are formed by shocks in a turbulent flow. In this work we present strong evidence in favor of the turbulent origin of the fragmentation of MCs. The most generic result of turbulent fragmentation is that dense postshock gas traces a gas component with a smaller velocity dispersion than lower density gas, since shocks correspond to regions of converging flows, where the kinetic energy of the turbulent motion is dissipated. Using synthetic maps of spectra of molecular transitions, computed from the results of numerical simulations of supersonic turbulence, we show that the dependence of velocity dispersion on gas density generates an observable relation between the rms velocity centroid and the integrated intensity (column density), sigma (V(o))-I, which is indeed found in the observational data. The comparison between the theoretical model (maps of synthetic (13)CO spectral with (13)CO maps from the Perseus, Rosette, and Taurus MC complexes shows excellent agreement in the o(V(o))-I relation. The sigma (V(o))-I relation of different observational maps with the same total rms velocity are remarkably similar, which is a strong indication of their origin from a very general property of the fluid equations, such as the turbulent fragmentation process. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Helsinki, Univ Helsinki Observ, SF-00014 Helsinki, Finland. Astron Observ, DK-2100 Copenhagen, Denmark. Theoret Astrophys Ctr, DK-2100 Copenhagen, Denmark. RP Padoan, P (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM ppadoan@cfa.harvard.edu; juvela@astro.helsinki.fi; agoodman@cfa.harvard.edu; aake@astro.ku.dk RI Juvela, Mika/H-6131-2011; Nordlund, Aake/M-4528-2014; Goodman, Alyssa/A-6007-2010; OI Juvela, Mika/0000-0002-5809-4834; Nordlund, Aake/0000-0002-2219-0541; Goodman, Alyssa/0000-0003-1312-0477; Padoan, Paolo/0000-0002-5055-5800 NR 86 TC 144 Z9 144 U1 0 U2 2 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 MAY 20 PY 2001 VL 553 IS 1 BP 227 EP 234 DI 10.1086/320636 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JA UT WOS:000169280400020 ER PT J AU Zhang, XL Lee, Y Bolatto, A Stark, AK AF Zhang, XL Lee, Y Bolatto, A Stark, AK TI CO (J=4 -> 3) and [C I] observations of the Carina molecular cloud complex SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : molecules; submillimeter ID PHOTODISSOCIATION REGIONS; ATOMIC CARBON; INTERSTELLAR-MEDIUM; SECULAR EVOLUTION; SPIRAL GALAXIES; ETA-CARINAE; DENSE CORES; TURBULENCE; NEBULA; SUBMILLIMETER AB We present large-area, fully sampled maps of the Carina molecular cloud complex in the CO (J = 4 -->3) and neutral carbon [C I] P-3(1) --> P-3(0) transitions. These data were obtained using the 1.7 m antarctic Submillimeter Telescope and Remote Observatory (AST/RO). The maps cover an area of approximately 3 deg(2) with a uniform 1' spatial sampling. Analysis of these data, in conjunction with CO (J = 1 -->0) data from the Columbia CO survey and the IRAS HIRES continuum maps for the same region, suggests that the spiral density wave shock associated with the Carina spiral arm may be playing an important role in the formation and dissociation of the cloud complex, as well as in maintaining the internal energy balance of the clouds in this region. Massive stars form at the densest regions of the molecular cloud complex. The minds and outflows associated with these stars have a disrupting effect on the complex and inject mechanical energy into the parent clouds, while the UV radiation from the young stars also heats the parent clouds. The present set of data suggests, however, that massive stars alone map not account for the energetics of the clouds in the Carina region. The details of the data and the correlation among the various data sets hint at the possible role that the spiral density wave shock plays in feeding interstellar turbulence and heating molecular clouds. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Korea Astron Observ, Taeduk Radio Astron Observ, Taejon 305348, South Korea. Boston Univ, Dept Astron, Inst Astrophys Res, Boston, MA 02215 USA. RP Zhang, XL (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,Mail Stop 78, Cambridge, MA 02138 USA. NR 59 TC 36 Z9 36 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2001 VL 553 IS 1 BP 274 EP 287 DI 10.1086/320628 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JA UT WOS:000169280400024 ER PT J AU D'Alessio, P Calvet, N Hartmann, L AF D'Alessio, P Calvet, N Hartmann, L TI Accretion disks around young objects. III. Grain growth SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; circumstellar matter; stars : formation; stars : pre-main-sequence ID T-TAURI-STARS; SPECTRAL ENERGY-DISTRIBUTIONS; CIRCUMSTELLAR DISKS; OPTICAL-CONSTANTS; SOLAR NEBULA; DUST; IRRADIATION; EMISSION AB We present detailed models of irradiated T Tauri disks including dust grain growth with power-law size distributions. The models assume complete mixing between dust and gas and solve for the vertical disk structure self-consistently including the heating effects of stellar irradiation as well as local viscous heating. For a given total dust mass, grain growth is found to decrease the vertical height of the surface where the optical depth to the stellar radiation becomes unity and thus the local irradiation heating, while increasing the disk emission at mm and submillimeter wavelengths. The resulting disk models are less geometrically thick than our previous models assuming interstellar medium dust, and agree better with observed spectral energy distributions and images of edge-on disks, like HK Tau/c and HH 30. The implications of models with grain growth for determining disk masses from long-wavelength emission are considered. C1 Amer Museum Nat Hist, Dept Astrophys, New York, NY 10024 USA. Natl Autonomous Univ Mexico, Inst Astron, Mexico City 04510, DF, Mexico. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP D'Alessio, P (reprint author), Amer Museum Nat Hist, Dept Astrophys, Cent Pk W & 79th St, New York, NY 10024 USA. NR 40 TC 337 Z9 337 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 MAY 20 PY 2001 VL 553 IS 1 BP 321 EP 334 DI 10.1086/320655 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JA UT WOS:000169280400028 ER PT J AU Garcia, MR McClintock, JE Narayan, R Callanan, P Barret, D Murray, SS AF Garcia, MR McClintock, JE Narayan, R Callanan, P Barret, D Murray, SS TI New evidence for black hole event horizons from Chandra SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; black hole physics; stars : individual (A0620-00, GRO J0422+32, GRO J1655-40, GS 2000+25, V404 Cygni, 4U 1543-47); stars : neutron; X-rays : stars ID ADVECTION-DOMINATED ACCRETION; SAGITTARIUS A-ASTERISK; X-RAY TRANSIENTS; MILLISECOND PULSAR; SAX J1808.4-3658; GALACTIC-CENTER; QUIESCENCE; MODEL; SPECTROSCOPY; EMISSION AB Previously we claimed that black hole X-ray novae (BHXNs) in quiescence are much less luminous than equivalent neutron star X-ray novae (NSXNs). This claim was based on the quiescent detection of a single short-period BHXN (A0620-00, P-orb = 7.8 hr) and two longer period BHXNs (GRO J1655-40, P-orb = 62.9 hr; V404 Cygni, P-orb = 155.3 hr), along with sensitive upper limits. Here we announce the detection of two more short-period BHXNs (GRO J0422+32, P-orb = 5.1 hr; GS 2000+25, P-orb = 8.3 hr), an upper limit for a third that is improved by 2 orders of magnitude (4U 1543 -47, P-orb = - 27.0 hr), and a new, much lower quiescent measurement of GRO J1655-40. Taken together, these new Chandra Advanced CCD Imaging Spectrometer measurements confirm that the quiescent X-ray luminosities of BHXNs are significantly lower than those of NSXNs. We argue that this provides strong evidence for the existence of event-horizons in BHXNs. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Coll, Dept Phys, Cork, Ireland. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse, France. RP Garcia, MR (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Narayan, Ramesh/0000-0002-1919-2730 NR 46 TC 96 Z9 97 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 MAY 20 PY 2001 VL 553 IS 1 BP L47 EP L50 DI 10.1086/320494 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JB UT WOS:000169280500012 ER PT J AU Winebarger, AR DeLuca, EE Golub, L AF Winebarger, AR DeLuca, EE Golub, L TI Apparent flows above an active region observed with the Transition Region and Coronal Explorer SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : corona ID STATIONARY SIPHON FLOWS; SOLAR CORONA; MODELS; LOOPS; VIEW AB The Transition Region and Coronal Explorer (TRACE) observed Active Region 8395 on 1998 December 1 from 1:30:00 to 3:00:00 UT at high cadence in the Fe IX/Fe x channel (log T-e approximate to 6.0). Throughout the observing time, brightness Variations along a dense bundle of coronal field lines in the southwest corner of the active region were observed. Movies made of this region give the impression of continuous intermittent outflow in this bundle of coronal loops; such apparent outflow is often seen in the TRACE data. In this Letter, we present an analysis of four separate flow events occurring in three different loops. These events are used as tracers of the how in order to characterize its physical properties, such as apparent velocity. The projected velocities of the intensity fronts of these flows land hence lower limits of true velocities) are between 5 and 20 Inn s(-1). Comparisons of the observed intensities with those predicted by a quasi-static model suggest that the events can be explained only by a mass flow from the chromosphere into the corona. The persistence of the hows, and their ubiquity in the TRACE observations, indicates that hydrostatic loops models are not applicable to this class of coronal structures. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM awinebarger@cfa.harvard.edu; edeluca@cfa.harvard.edu; lgolub@cfa.harvard.edu RI DeLuca, Edward/L-7534-2013 OI DeLuca, Edward/0000-0001-7416-2895 NR 10 TC 55 Z9 55 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 MAY 20 PY 2001 VL 553 IS 1 BP L81 EP L84 DI 10.1086/320496 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 442JB UT WOS:000169280500020 ER PT J AU Robinson, MH AF Robinson, MH TI A different nature - The paradoxical world of zoos and their uncertain future SO SCIENCE LA English DT Book Review C1 Smithsonian Inst, Natl Zool Pk, Washington, DC 20008 USA. NR 1 TC 1 Z9 1 U1 1 U2 5 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 MAY 18 PY 2001 VL 292 IS 5520 BP 1304 EP 1305 DI 10.1126/science.1060030 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 435DV UT WOS:000168862900023 ER PT J AU Weaver, HA Sekanina, Z Toth, I Delahodde, CE Hainaut, OR Lamy, PL Bauer, JM A'Hearn, MF Arpigny, C Combi, MR Davies, JK Feldman, PD Festou, MC Hook, R Jorda, L Keesey, MSW Lisse, CM Marsden, BG Meech, KJ Tozzi, GP West, R AF Weaver, HA Sekanina, Z Toth, I Delahodde, CE Hainaut, OR Lamy, PL Bauer, JM A'Hearn, MF Arpigny, C Combi, MR Davies, JK Feldman, PD Festou, MC Hook, R Jorda, L Keesey, MSW Lisse, CM Marsden, BG Meech, KJ Tozzi, GP West, R TI HST and VLT investigations of the fragments of comet C/1999 S4 (LINEAR) SO SCIENCE LA English DT Article ID NUCLEUS; BREAKUP; SPLIT; DUST AB At least 16 fragments were detected in images of comet C/1999 S4 (LINEAR) taken on 5 August 2000 with the Hubble Space Telescope (HST) and on 6 August with the Very Large Telescope (VLT). Photometric analysis of the fragments indicates that the largest ones have effective spherical diameters of about 100 meters, which implies that the total mass in the observed fragments was about 2 x 10(9) kilograms. The comet's dust tail, which was the most prominent optical feature in August, was produced during a major fragmentation event, whose activity peaked on UT 22.8 +/- 0.2 July 2000. The mass of small particles (diameters less than about 230 micrometers) in the tail was about 4 x 10(8) kilograms, which is comparable to the mass contained in a large fragment and to the total mass lost from water sublimation after 21 July 2000 (about 3 x 108 kilograms). HST spectroscopic observations during 5 and 6 July 2000 demonstrate that the nucleus contained little carbon monoxide ice (ratio of carbon monoxide to water is less than or equal to 0.4%), which suggests that this volatile species did not play a role in the fragmentation of C/1999 S4 (LINEAR). C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Konkoly Observ Budapest, H-1525 Budapest, Hungary. European So Observ, Santiago 19, Chile. CNRS, Astron Spatiale Lab, F-13376 Marseille 12, France. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Liege, Inst Astrophys, B-4000 Liege, Belgium. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. Joint Astron Ctr, Hilo, HI 96720 USA. Observ Midi Pyrenees, F-31400 Toulouse, France. European So Observ, D-85748 Garching, Germany. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osserv Astrofis Arcetri, I-50125 Florence, Italy. RP Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI Combi, Michael/J-1697-2012; Weaver, Harold/D-9188-2016; Lisse, Carey/B-7772-2016; OI Combi, Michael/0000-0002-9805-0078; Lisse, Carey/0000-0002-9548-1526; Tozzi, Gian Paolo/0000-0003-4775-5788 NR 23 TC 63 Z9 63 U1 1 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD MAY 18 PY 2001 VL 292 IS 5520 BP 1329 EP 1333 DI 10.1126/science.1058606 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 435DV UT WOS:000168862900034 PM 11359001 ER PT J AU Lisse, CM Christian, DJ Dennerl, K Meech, KJ Petre, R Weaver, HA Wolk, SJ AF Lisse, CM Christian, DJ Dennerl, K Meech, KJ Petre, R Weaver, HA Wolk, SJ TI Charge exchange-induced X-ray emission from comet C/1999 S4 (LINEAR) SO SCIENCE LA English DT Article ID EXTREME-ULTRAVIOLET EMISSION; SOLAR-WIND; HALE-BOPP; HYAKUTAKE; IONS; SPECTRA AB Using soft x-ray observations of the bright new comet C/1999 S4 (LIN EAR) with the Chandra x-ray observatory, we have detected x-ray line emission created by charge exchange between highly ionized solar wind minor ions and neutral gases in the comet's coma. The emission morphology was symmetrically crescent shaped and extended out to 300,000 kilometers from the nucleus. The emission spectrum contains 6 lines at 320, 400, 490, 560, 600, and 670 electron volts, attributable to electron capture and radiative deexcitation by the solar wind species C+5, C+6, N+7, O+7, and O+8. A contemporaneous T-day soft x-ray Light curve obtained using the Extreme Ultraviolet Explorer demonstrates a large increase in the comet's emission coincident with a strong solar flare on 14 and 15 July 2000. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Comp Sci Corp, Sci Operat, Baltimore, MD 21218 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Chandra Xray Ctr, Cambridge, MA 02138 USA. RP Lisse, CM (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RI Weaver, Harold/D-9188-2016; Lisse, Carey/B-7772-2016; OI Lisse, Carey/0000-0002-9548-1526; Wolk, Scott/0000-0002-0826-9261 NR 34 TC 112 Z9 113 U1 0 U2 4 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 18 PY 2001 VL 292 IS 5520 BP 1343 EP 1348 DI 10.1126/science.292.5520.1343 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 435DV UT WOS:000168862900037 PM 11359004 ER PT J AU Torrelles, JM Patel, NA Gomez, JF Ho, PTP Rodriguez, LF Anglada, G Garay, G Greenhill, L Curiel, S Canto, J AF Torrelles, JM Patel, NA Gomez, JF Ho, PTP Rodriguez, LF Anglada, G Garay, G Greenhill, L Curiel, S Canto, J TI Spherical episodic ejection of material from a young star SO NATURE LA English DT Article ID THERMAL RADIO JET; WATER MASERS; CEPHEUS-A; MASS OUTFLOW; H2O MASERS; REGIONS; EMISSION; MOTION; HW2 AB The exact processes by which interstellar matter condenses to form young stars are of great interest, in part because they bear on the formation of planets like our own from the material that fails to become part of the star. Theoretical models suggest that ejection of gas during early phases of stellar evolution is a key mechanism for removing excess angular momentum, thereby allowing material to drift inwards towards the star through an accretion disk(1,2). Such ejections also limit the mass that can be accumulated by the stellar core(1,2). To date, these ejections have been observed to be bipolar and highly collimated, in agreement with theory. Here we report observations at very high angular resolution of the proper motions of an arc of water-vapour masers near a very young, massive star in Cepheus. We rnd that the arc of masers can be fitted to a circle with an accuracy of one part in a thousand, and that the structure is expanding. Only a sphere will always produce a circle in projection, so our observations strongly suggest that the perfectly spherical ejection of material from this star took place about 33 years earlier. The spherical symmetry of the ejecta and its episodic nature are very surprising in the light of present theories. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CSIC, IEEC, ES-08034 Barcelona, Spain. CSIC, Inst Ciencias Espacio, ES-08034 Barcelona, Spain. INTA, Lab Astrofis Espacial & Fis Fundamental, Madrid 28080, Spain. Univ Nacl Autonoma Mexico, Inst Astron, Morelia 58089, Michoacan, Mexico. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Univ Chile, Dept Astron, Santiago, Chile. Univ Nacl Autonoma Mexico, Inst Astron, Mexico City 04510, DF, Mexico. RP Ho, PTP (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM ho@cfa.harvard.edu RI Garay, Guido/H-8840-2013; Gomez, Jose Francisco/D-8392-2016; OI Garay, Guido/0000-0003-1649-7958; Gomez, Jose Francisco/0000-0002-7065-542X; Torrelles, Jose Maria/0000-0002-6896-6085 NR 21 TC 54 Z9 54 U1 1 U2 5 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 17 PY 2001 VL 411 IS 6835 BP 277 EP 280 DI 10.1038/35077020 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 432RT UT WOS:000168710000038 PM 11357123 ER PT J AU Jiggins, CD Naisbit, RE Coe, RL Mallet, J AF Jiggins, CD Naisbit, RE Coe, RL Mallet, J TI Reproductive isolation caused by colour pattern mimicry SO NATURE LA English DT Article ID HELICONIUS BUTTERFLIES; NATURAL-SELECTION; RACE FORMATION; WARNING-COLOR; SPECIATION; REINFORCEMENT; EVOLUTION; CONSEQUENCES; DIVERGENCE AB Speciation is facilitated if ecological adaptation directly causes assortative mating(1), but few natural examples are known. Here we show that a shift in colour pattern mimicry was crucial in the origin of two butterfly species. The sister species Heliconius melpomene and Heliconius cydno recently diverged to mimic different model taxa, and our experiments show that their mimetic coloration is also important in choosing mates. Assortative mating between the sister species means that hybridization is rare in nature, and the few hybrids that are produced are nonmimetic, poorly adapted intermediates. Thus, the mimetic shift has caused both pre-mating and post-mating isolation. In addition, individuals from a population of H. melpomene allopatric to H. cydno court and mate with H. cydno more readily than those from a sympatric population. This suggests that assortative mating has been enhanced in sympatry. C1 UCL, Galton Lab, London NW1 2HE, England. Smithsonian Trop Res Inst, Balboa, Panama. Univ Cambridge Downing Coll, Cambridge CB2 1DQ, England. RP Jiggins, CD (reprint author), UCL, Galton Lab, 4 Stephenson Way, London NW1 2HE, England. EM jigginsc@naos.si.edu RI Jiggins, Chris/B-9960-2008; Naisbit, Russell/B-9658-2011; mallet, james/B-5114-2008; OI Jiggins, Chris/0000-0002-7809-062X; Naisbit, Russell/0000-0003-0190-9323; Mallet, James/0000-0002-3370-0367 NR 23 TC 341 Z9 356 U1 13 U2 118 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 17 PY 2001 VL 411 IS 6835 BP 302 EP 305 DI 10.1038/35077075 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 432RT UT WOS:000168710000046 PM 11357131 ER PT J AU Brocksopp, C Jonker, PG Fender, RP Groot, PJ van der Klis, M Tingay, SJ AF Brocksopp, C Jonker, PG Fender, RP Groot, PJ van der Klis, M Tingay, SJ TI The 1997 hard-state outburst of the X-ray transient GS 1354-64/BW Cir SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; stars : individual : GS 1354-64; X-rays : stars ID QUASI-PERIODIC OSCILLATION; BLACK-HOLE CANDIDATE; CYGNUS X-1; TIMING EXPLORER; RADIO; VARIABILITY; NOVA; GRO-J0422+32; ULTRAVIOLET; EVOLUTION AB We present observations of the 1997 outburst of the X-ray transient GS 1354-64 (BW Cir) at X-ray, optical and, for the first time, radio wavelengths; our results include upper limits to the linear and circular polarization for the radio data. The X-ray outburst was unusual in that the source remained in the low/hard X-ray state throughout; the X-ray peak was also preceded by at least one optical outburst, suggesting that it was an 'outside-in' outburst similar to those observed in dwarf novae systems, although possibly taking place on a viscous time-scale in this case. It therefore indicates that the optical emission was not dominated by the reprocessing of X-rays, but that instead we see the instability directly. While the radio source was too faint to detect any extended structure, spectral analysis of the radio data and a comparison with other similar systems suggest that mass ejections, probably in the form of a jet, took place and that the emitted synchrotron spectrum may have extended as far as infrared wavelengths. Finally, we compare this 1997 outburst of GS 1354-64 with possible previous outbursts and also with other hard-state objects, both transient and persistent. It appears that a set of characteristics-such as a weak, flat-spectrum radio jet, a mHz QPO increasing in frequency, a surprisingly high optical/X-ray luminosity ratio, and the observed optical peak preceding the X-ray peak-may be common to all hard-state X-ray transients. C1 Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Amsterdam, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Australia Telescope Natl Facil, Paul Wild Observ, Narrabri, NSW 2390, Australia. RP Brocksopp, C (reprint author), Open Univ, Dept Phys & Astron, Walton Hall, Milton Keynes MK7 6AA, Bucks, England. RI Tingay, Steven/B-5271-2013; Groot, Paul/K-4391-2016 OI Groot, Paul/0000-0002-4488-726X NR 64 TC 41 Z9 41 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 11 PY 2001 VL 323 IS 2 BP 517 EP 528 DI 10.1046/j.1365-8711.2001.04193.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 441KM UT WOS:000169229600029 ER PT J AU Krebs, E AF Krebs, E TI The tango, Borges and translation (Comment) SO TLS-THE TIMES LITERARY SUPPLEMENT LA English DT Letter C1 Smithsonian Inst, Dept Anthropol, Washington, DC 20560 USA. RP Krebs, E (reprint author), Smithsonian Inst, Dept Anthropol, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU TIMES SUPPLEMENTS LIMITED PI MARKET HARBOROUGH PA TOWER HOUSE, SOVEREIGN PARK, MARKET HARBOROUGH LE87 4JJ, ENGLAND SN 0307-661X EI 1366-7211 J9 TLS-TIMES LIT SUPPL JI TLS-Times Lit. Suppl. PD MAY 11 PY 2001 IS 5119 BP 17 EP 17 PG 1 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA 434PU UT WOS:000168825700027 ER PT J AU Haiman, Z Loeb, A AF Haiman, Z Loeb, A TI What is the highest plausible redshift of luminous quasars? SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; cosmology : theory; galaxies : formation; quasars : general ID ACTIVE GALACTIC NUCLEI; BLACK-HOLES; GALAXY FORMATION; MASS; OBJECTS; EVOLUTION; MODELS; DISTRIBUTIONS; CONSTRAINTS; SIZE AB The recent discoveries of luminous quasars at high redshifts imply that black holes more massive than a few billion solar masses were already assembled when the universe was less than a billion years old. We show that the existence of these black holes is not surprising in popular hierarchical models of structure formation. For example, the black hole needed to power the quasar SDSS 1044-0125 at z = 5.8 could arise naturally from the growth of stellar-mass seeds forming at z > 10, when typical values are assumed for the radiative accretion efficiency (similar to0.1) and the bolometric accretion luminosity in Eddington units (similar to1). Nevertheless, SDSS 1044-0125 yields a nontrivial constraint on a combination of these parameters. Extrapolating our model to future surveys, we derive the highest plausible redshift for quasars that are not lensed or beamed, as a function of their apparent magnitude. We find that at a limiting magnitude of K similar to 20, quasar surveys can yield strong constraints on the growth of supermassive black holes out to z similar to 10. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Haiman, Z (reprint author), Princeton Univ Observ, Peyton Hall, Princeton, NJ 08544 USA. NR 40 TC 160 Z9 160 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2001 VL 552 IS 2 BP 459 EP 463 DI 10.1086/320586 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 439TM UT WOS:000169133700005 ER PT J AU Dave, R Cen, R Ostriker, JP Bryan, GL Hernquist, L Katz, N Weinberg, DH Norman, ML O'Shea, B AF Dave, R Cen, R Ostriker, JP Bryan, GL Hernquist, L Katz, N Weinberg, DH Norman, ML O'Shea, B TI Baryons in the warm-hot intergalactic medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; intergalactic medium; large-scale structure of universe; methods : numerical ID LY-ALPHA FOREST; GALAXY FORMATION; LOW-REDSHIFT; UNIVERSE; CLUSTERS; MODEL; COSMOLOGY; STATE AB Approximately 30%-40% of all baryons in the present-day universe reside in a warm-hot intergalactic medium (WHIM), with temperatures in the range 10(5) < T < 10(7) K. This is a generic prediction from six hydrodynamic simulations of currently favored structure formation models having a wide variety of numerical methods, input physics, volumes, and spatial resolutions. Most of these warm-hot baryons reside in diffuse large-scale structures with a median overdensity around 10-30, not in virialized objects such as galaxy groups or galactic halos. The evolution of the WHIM is primarily driven by shock heating from gravitational perturbations breaking on mildly nonlinear, nonequilibrium structures such as filaments. Supernova feedback energy and radiative cooling play lesser roles in its evolution. WHIM gas may be consistent with observations of the 0.25 keV X-ray background without being significantly heated by nongravitational processes because the emitting gas is very diffuse. Our results confirm and extend previous work by Cen & Ostriker and Dave et al. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. RP Dave, R (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NR 40 TC 539 Z9 539 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 MAY 10 PY 2001 VL 552 IS 2 BP 473 EP 483 DI 10.1086/320548 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 439TM UT WOS:000169133700007 ER PT J AU Harrus, IM Slane, PO Smith, RK Hughes, JP AF Harrus, IM Slane, PO Smith, RK Hughes, JP TI A new ASCA and ROSAT study of the supernova remnant G272.2-3.2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : individual (G272.2-3.2); shock waves; supernova remnants; X-rays : ISM ID FORMED DENSE SHELL; X-RAY-EMISSION; INTERSTELLAR-MEDIUM; THERMAL CONDUCTION; MODELING W44; HOT INTERIOR; GRADIENT; CLOUDS; PLASMA; SOLAR AB G272.2-3.2 is a supernova remnant (SNR) characterized by an apparent centrally brightened X-ray morphology and thermally dominated X-ray emission. Because of this combination of Sedov-type (thermal emission) and non-Sedov-type (non-shell-like morphology) features, the remnant is classified as a "thermal composite" SNR. This class of remnant is still poorly understood, in part because of the difficulties in modeling accurately all the physical conditions which shape the emission morphology. This paper presents a combined analysis of data from the ASCA and ROSAT satellites coupled with previous results at other wavelengths. We find that the X-ray emission from G272.2-3.2 is best described by a nonequilibrium ionization (NEI) model with a temperature around 0.70 keV, an ionization timescale of 3200 cm(-3) yr, and a relatively high column density (N-H similar to 10(22) atoms cm(-2)). We look into the possible explanations for the apparent morphology of G272.2-3.2 using several models (among which are both cloud evaporation and thermal conduction models). For each of the models considered, we examine all the implications on the evolution of G272.2-3.2. C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Rutgers State Univ, Piscataway, NJ 08854 USA. RP Harrus, IM (reprint author), NASA, Goddard Space Flight Ctr, USRA, Bldg 2,Code 662, Greenbelt, MD 20771 USA. NR 32 TC 18 Z9 18 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 MAY 10 PY 2001 VL 552 IS 2 BP 614 EP 623 DI 10.1086/320577 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 439TM UT WOS:000169133700018 ER PT J AU Brown, TM Charbonneau, D Gilliland, RL Noyes, RW Burrows, A AF Brown, TM Charbonneau, D Gilliland, RL Noyes, RW Burrows, A TI Hubble Space Telescope time-series photometry of the transiting planet of HD 209458 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : eclipsing; planetary systems; stars : individual (HD 209458); techniques : photometric ID EXTRASOLAR GIANT PLANETS; TAU-BOOTIS; HD-209458; SPECTRA; MISSION; SYSTEM; STARS AB We have observed four transits of the planet of HD 209458 using the STIS spectrograph on the Hubble Space Telescope (HST). Summing the recorded counts over wavelength between 582 and 638 nm yields a photometric time series with 80 s time sampling and relative precision of about 1.1 x 10(-4) per sample. The folded light curve can be fitted within observational errors using a model consisting of an opaque circular planet transiting a limb-darkened stellar disk. In this way we estimate the planetary radius R-p = 1.347 +/- 0.060 R-Jup, the orbital inclination i = 86.degrees6 +/- 0.degrees 14, the stellar radius R-* = 1.146 +/- 0.050 R., and one parameter describing the stellar limb darkening. Our estimated radius is smaller than those from earlier studies but is consistent within measurement errors and also with theoretical estimates of the radii of irradiated Jupiter-like planets. Satellites or rings orbiting the planet would, if large enough, be apparent from distortions of the light curve or from irregularities in the transit timings. We find no evidence for either satellites or rings, with upper limits on satellite radius and mass of 1.2 R + and 3 M +, respectively. Opaque rings, if present, must be smaller than 1.8 planetary radii in radial extent. The high level of photometric precision attained in this experiment confirms the feasibility of photometric detection of Earth-sized planets circling Sun-like stars. C1 Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. RP Natl Ctr Atmospher Res, High Altitude Observ, 3450 Mitchell Lane, Boulder, CO 80307 USA. EM timbrown@hao.ucar.edu; dcharbonneau@cfa.harvard.edu; gillil@stsci.edu; moyes@cfa.harvard.edu; aburrows@as.arizona.edu OI Charbonneau, David/0000-0002-9003-484X NR 33 TC 412 Z9 413 U1 0 U2 8 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 MAY 10 PY 2001 VL 552 IS 2 BP 699 EP 709 DI 10.1086/320580 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 439TM UT WOS:000169133700026 ER PT J AU Chou, HS AF Chou, HS TI The dependence of dynamo alpha-effect on Reynolds numbers, magnetic Prandtl number, and the statistics of magnetohydrodynamic turbulence SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; turbulence ID MEAN-FIELD ELECTRODYNAMICS; CONSISTENCY; TRANSPORT AB We generalize the derivation of the dynamo coefficient alpha of Field et al. to include the following two aspects: first, the decorrelation times of velocity field and magnetic field are different; second, the magnetic Prandtl number can be arbitrary. We find that the contributions of velocity field and magnetic field to the alpha -effect are not equal, but affected by their different statistical properties. In the limit of large kinetic Reynolds number and large magnetic Reynolds number, alpha -coefficient may not be small if the decorrelation times of velocity field and magnetic field are shorter than the eddy turnover time of the MHD turbulence. We also show that under certain circumstances, for example if the kinetic helicity and current helicity are comparable, alpha depends insensitively on magnetic Prandtl number, while if either the kinetic helicity or the current helicity is dominated by the other one, a different magnetic Prandtl number will significantly change the dynamo alpha -effect. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Chou, HS (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 36 TC 3 Z9 3 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 MAY 10 PY 2001 VL 552 IS 2 BP 803 EP 820 DI 10.1086/320561 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 439TM UT WOS:000169133700036 ER PT J AU King, AR Davies, MB Ward, MJ Fabbiano, G Elvis, M AF King, AR Davies, MB Ward, MJ Fabbiano, G Elvis, M TI Ultraluminous X-ray sources in external galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; X-rays : stars ID BLACK-HOLES; CYGNUS X-2; GLOBULAR-CLUSTERS; MASS-TRANSFER; EVOLUTION; BINARIES; TRANSIENTS; NUCLEI AB We investigate models for the class of ultraluminous nonnuclear X-ray sources (i.e., ultraluminous compact X-ray sources [ULXs]) seen in a number of galaxies and probably associated with star-forming regions. Models in which the X-ray emission is assumed to be isotropic run into several difficulties. In particular, the formation of sufficient numbers of the required ultramassive black hole X-ray binaries is problematic, and the likely transient behavior of the resulting systems is not in good accord with observation. The assumption of mild X-ray beaming suggests instead that ULXs may represent a short-lived but extremely common stage in the evolution of a wide class of X-ray binaries. The best candidate for this is the phase of thermal-timescale mass transfer that is inevitable in many intermediate- and high-mass X-ray binaries. This in turn suggests a link with the Galactic microquasars. The short lifetimes of high-mass X-ray binaries would explain the association of ULXs with episodes of star formation. These considerations still allow the possibility that individual ULXs may contain extremely massive black holes. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP King, AR (reprint author), Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England. NR 36 TC 311 Z9 314 U1 3 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2001 VL 552 IS 2 BP L109 EP L112 DI 10.1086/320343 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 439TN UT WOS:000169133800007 ER PT J AU Zhang, QZ Hunter, TR Brand, J Sridharan, TK Molinari, S Kramer, MA Cesaroni, R AF Zhang, QZ Hunter, TR Brand, J Sridharan, TK Molinari, S Kramer, MA Cesaroni, R TI Search for CO outflows toward a sample of 69 high-mass protostellar candidates: Frequency of occurrence SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; HII regions; ISM : clouds; ISM : jets and outflows; stars : formation ID ULTRACOMPACT HII-REGIONS; LUMINOUS IRAS SOURCES; BIPOLAR MOLECULAR OUTFLOWS; FAR-INFRARED SOURCES; H-II REGIONS; (PROTO)STAR IRAS-20126+4104; STAR-FORMATION; CLOUDS; PRECURSORS; DISK AB A survey for molecular outflows was carried out by mapping the CO J = 2-1 line toward a sample of 69 luminous IRAS point sources. Sixty objects have IRAS luminosities from 10(3) to 10(5) L, and are associated with dense gas traced by NH,, identifying them as high-mass star-forming regions. Among 69 sources, 65 sources have data that are suitable for outflow identification. Thirty-nine regions show spatially confined high-velocity wing emission in CO, indicative of molecular outflows. Most objects without identifiable outflows Lie within 0 degrees < l < 50 degrees where outflow signatures are confused by multiple cloud components along the line of sight. Excluding 26 sources with 0 degrees < l < 50 degrees, we found 35 outflows out of 39 sources, which yields an outflow detection/rate of 90%. Many of the outflows contain masses of more than 10 M. and have momenta of a few hundred M. km s(-1), at least 2 orders of magnitude larger than those in typical low-mass outflows. This class of massive and energetic outflows is most likely driven by high-mass young stellar objects. The high detection rate indicates that molecular outflows are common toward high-mass young stars. Given the connection between outflows and accretion disks in low-mass stars, we suggest that high-mass stars may form via an accretion-outflow process, similar to their low-mass counterparts. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CNR, Ist Radioastron, I-40129 Bologna, Italy. CNR, Ist Fis Spazio Interplanetario, I-00133 Rome, Italy. Oberlin Coll, Oberlin, OH 44074 USA. Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. RP Zhang, QZ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Kramer, Mark/A-1291-2014; Molinari, Sergio/O-4095-2016; OI Molinari, Sergio/0000-0002-9826-7525; Brand, Jan/0000-0003-1615-9043; Cesaroni, Riccardo/0000-0002-2430-5103; Hunter, Todd/0000-0001-6492-0090; Zhang, Qizhou/0000-0003-2384-6589 NR 35 TC 85 Z9 86 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 MAY 10 PY 2001 VL 552 IS 2 BP L167 EP L170 DI 10.1086/320345 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 439TN UT WOS:000169133800020 ER PT J AU Erwin, DH AF Erwin, DH TI Lessons from the past: Biotic recoveries from mass extinctions SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT National-Academy-of-Sciences Colloquium on the Future of Evolution CY MAR 16-20, 2000 CL IRVINE, CA SP Natl Acad Sci ID CRETACEOUS-TERTIARY BOUNDARY; TAXONOMIC DIVERSITY; LATEST ORDOVICIAN; SOUTH CHINA; EVENT; END; PALEOECOLOGY; SURVIVAL; DIVERSIFICATION; ORIGINATION AB Although mass extinctions probably account for the disappearance of less than 5% of all extinct species, the evolutionary opportunities they have created have had a disproportionate effect on the history of life. Theoretical considerations and simulations have suggested that the empty niches created by a mass extinction should refill rapidly after extinction ameliorates. Under logistic models, this biotic rebound should be exponential, slowing as the environmental carrying capacity is approached. Empirical studies reveal a more complex dynamic, including positive feedback and an exponential growth phase during recoveries. Far from a model of refilling ecospace, mass extinctions appear to cause a collapse of ecospace, which must be rebuilt during recovery. Other generalities include the absence of a clear correlation between the magnitude of extinction and the pace of recovery or the resulting ecological and evolutionary disruption the presence of a survival interval, with few originations, immediately after an extinction and preceding the recovery phase, and the presence of many lineages that persist through an extinction event only to disappear during the subsequent recovery. Several recoveries include numerous missing lineages, groups that are found before the extinction, then latter in the recovery, but are missing during the initial survival-recovery phase. The limited biogeographic studies of recoveries suggest considerable variability between regions. C1 Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. RP Smithsonian Inst, Dept Paleobiol, MRC-121, Washington, DC 20560 USA. EM emin.doug@nmnh.si.edu RI Erwin, Douglas/A-9668-2009 NR 74 TC 153 Z9 161 U1 10 U2 34 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 MAY 8 PY 2001 VL 98 IS 10 BP 5399 EP 5403 DI 10.1073/pnas.091092698 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 431GK UT WOS:000168623300009 PM 11344285 ER PT J AU Jackson, JBC AF Jackson, JBC TI What was natural in the coastal oceans? SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT National-Academy-of-Sciences Colloquium on the Future of Evolution CY MAR 16-20, 2000 CL IRVINE, CALIFORNIA SP Natl Acad Sci ID CAPITA INTERACTION STRENGTH; KELP FOREST COMMUNITIES; MULTIPLE STABLE POINTS; CHESAPEAKE-BAY; THALASSIA-TESTUDINUM; FLORIDA BAY; CORAL-REEFS; HISTORICAL-PERSPECTIVE; MARINE ECOSYSTEMS; UNITED-STATES AB Humans transformed Western Atlantic coastal marine ecosystems before modern ecological investigations began, Paleoecological. archeological, and historical reconstructions demonstrate incredible losses of large vertebrates and oysters from the entire Atlantic coast. Untold millions of large fishes, sharks, sea turtles, and manatees were removed from the Caribbean in the 17th to 19th centuries. Recent collapses of reef corals and seagrasses are due ultimately to losses of these large consumers as much as to more recent changes in climate, eutrophication, or outbreaks of disease. Overfishing in the 19th century reduced vast beds of oysters in Chesapeake Bay and other estuaries to a few percent of pristine abundances and promoted eutrophication. Mechanized harvesting of bottom fishes like cod set off a series of trophic cascades that eliminated kelp forests and then brought them back again as fishers fished their way down food webs to small invertebrates. Lastly, but most pervasively, mechanized harvesting df the entire continental shelf decimated large, long-lived fishes and destroyed three-dimensional habitats built up by sessile corals, bryozoans, and sponges. The universal pattern of losses demonstrates that no coastal ecosystem is pristine and few wild fisheries are sustainable along the entire Western Atlantic coast. Reconstructions of ecosystems lost only a century or two ago demonstrate attainable goals of establishing large and effective marine reserves if society is willing to pay the costs. Historical reconstructions provide a new scientific framework for manipulative experiments at the ecosystem scale to explore the feasibility and benefits of protection of our living coastal resources. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archeol, Balboa, Panama. RP Jackson, JBC (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NR 136 TC 288 Z9 300 U1 13 U2 216 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 MAY 8 PY 2001 VL 98 IS 10 BP 5411 EP 5418 DI 10.1073/pnas.091092898 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 431GK UT WOS:000168623300011 PM 11344287 ER PT J AU Knowlton, N AF Knowlton, N TI The future of coral reefs SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT National-Academy-of-Sciences Colloquium on the Future of Evolution CY MAR 16-20, 2000 CL IRVINE, CALIFORNIA SP Natl Acad Sci ID HABITAT DESTRUCTION; PHASE-SHIFTS; EVOLUTIONARY HISTORY; ENVIRONMENTAL-CHANGE; SELF-FERTILIZATION; MULTIPLE STRESSORS; DIADEMA-ANTILLARUM; CARIBBEAN CORALS; THORNS STARFISH; SPAWNING CORALS AB Coral reefs, with their millions of species, have changed profoundly because of the effects of people, and will continue to do so for the foreseeable future. Reefs are subject to many of the same processes that affect other human-dominated ecosystems, but some special features merit emphasis: (i) Many dominant reef builders spawn eggs and sperm into the water column, where fertilization occurs. They are thus particularly vulnerable to Allee effects, including potential extinction associated with chronic reproductive failure. (ii) The corals likely to be most resistant to the effects of habitat degradation are small, short-lived "weedy" corals that have limited dispersal capabilities at the larval stage. Habitat degradation, together with habitat fragmentation, will therefore lead to the establishment of genetically isolated clusters of inbreeding corals. (iii) Increases in average sea temperatures by as little as 1 degreesC, a likely result of global climate change, can cause coral "bleaching" (the breakdown of coral-algal symbiosis), changes in symbiont communities, and coral death. (iv) The activities of people near reefs increase both fishing pressure and nutrient inputs. In general, these processes favor more rapidly growing competitors, often fleshy seaweeds, and may also result in explosions of predator populations. (v) Combinations of stress appear to be associated with threshold responses and Ecological surprises, including devastating pathogen outbreaks. (vi) The fossil record suggests that corals as a group are more likely to suffer extinctions than some of the groups that associate with them, whose habitat requirements may be less stringent. C1 Univ Calif San Diego, Scripps Inst Oceanog, Marine Biol Res Div 0202, La Jolla, CA 92093 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Knowlton, N (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Marine Biol Res Div 0202, La Jolla, CA 92093 USA. NR 115 TC 257 Z9 275 U1 16 U2 124 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 MAY 8 PY 2001 VL 98 IS 10 BP 5419 EP 5425 DI 10.1073/pnas.091092998 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 431GK UT WOS:000168623300012 PM 11344288 ER PT J AU Robertson, DR AF Robertson, DR TI Population maintenance among tropical reef fishes: Inferences from small-island endemics SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MARINE POPULATIONS; SHORE FISHES; RECRUITMENT; CONNECTIVITY; RETENTION; EVOLUTION; REGION; LARVAE; OCEAN; SEA AB To what extent do local populations of tropical reef fishes persist through the recruitment of pelagic larvae to their natal reef? Endemics from small, isolated islands can help answer that question by indicating whether special biological attributes are needed for long-term survival under enforced localization in high-risk situations. Taxonomically and biologically, the endemics from seven such islands are broadly representative of their regional faunas. As natal-site recruitment occurs among reef fishes in much less isolated situations, these characteristics of island endemics indicate that a wide range of reef fishes could have persistent self-sustaining local populations. Because small islands regularly support substantial reef fish faunas, regional systems of small reserves could preserve much of the diversity of these fishes. C1 Smithsonian Trop Res Inst Panama, APO, AA 34002 USA. RP Smithsonian Trop Res Inst Panama, Unit 0948, APO, AA 34002 USA. EM ross.robertson@stri.org NR 42 TC 65 Z9 66 U1 0 U2 9 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 MAY 8 PY 2001 VL 98 IS 10 BP 5667 EP 5670 DI 10.1073/pnas.091367798 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 431GK UT WOS:000168623300054 PM 11331752 ER PT J AU Anderson, JD AF Anderson, JD TI History of high-speed flight and its technical development SO AIAA JOURNAL LA English DT Article AB Theodore von Karman lived for 82 years. During his lifetime he witnessed, and to some degree participated in, the technical development of high-speed flight, from the regime of subsonic flight near the speed of sound to transonic, supersonic, and hypersonic flight. What a remarkable time to have lived. This paper is a brief summary of the historical and technical evolution of flight, as witnessed by von Karman. C1 Univ Maryland, Dept Aerosp Engn, College Pk, MD 20742 USA. Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. RP Anderson, JD (reprint author), Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. NR 20 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2001 VL 39 IS 5 BP 761 EP 771 DI 10.2514/2.1385 PG 11 WC Engineering, Aerospace SC Engineering GA 431BK UT WOS:000168611900001 ER PT J AU McCormick, MK Gross, KL Smith, RA AF McCormick, MK Gross, KL Smith, RA TI Danthonia spicata (Poaceae) and Atkinsonella hypoxylon (Balansiae): Environmental dependence of a symbiosis SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE Danthonia spicata; environmental variability; plant-fungal interactions; spatial heterogeneity; symbiosis ID FUNGAL ENDOPHYTE-INFECTION; TALL FESCUE; COMPETITIVE INTERACTIONS; ACREMONIUM-COENOPHIALUM; LOLIUM-PERENNE; GRASSES; MAINTENANCE; TOXICITY; GROWTH AB Epiphytic and endophytic fungal infections often enhance plant growth. However, supporting active fungal tissue may be costly to plants in low-nutrient conditions and may affect the spatial distribution of host plants in heterogeneous environments. We examined the field distribution of Danthonia spicata infected and uninfected by the epiphytic fungus Atkinsonella hypoxylon relative to soil resource levels. We also conducted a greenhouse experiment to determine how D. spicata growth and performance responded to soil fertility and moisture. In two of three field populations, locations where A. hypoxylon occurred had higher ammonia, but lower soil moisture, than locations where D. spicata were uninfected. Infected and uninfected plants had similar growth rates across greenhouse treatments, but infected plants had a performance (size x survival) disadvantage relative to uninfected plants in high-nutrient, high-moisture and low-nutrient, low-moisture conditions. Field locations with D. spicata had low soil moisture, thus the performance disadvantage of infected plants in low-nutrient, low-moisture conditions corresponds to field observations that infected plants are rare in habitats with low ammonia. In a field common garden, infected plants had higher nitrogen concentrations than uninfected plants, suggesting that high nitrogen demand by A. hypoxylon may exclude infected plants from low-fertility field locations. C1 Michigan State Univ, Wk Kellogg Biol Stn, Hickory Corners, MI 49060 USA. Michigan State Univ, Dept Zool, E Lansing, MI 48823 USA. Michigan State Univ, Program Ecol Evolutionary Biol & Behav, E Lansing, MI 48823 USA. Michigan State Univ, Dept Bot & Plant Pathol, E Lansing, MI 48823 USA. RP McCormick, MK (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. NR 33 TC 7 Z9 8 U1 0 U2 1 PU BOTANICAL SOC AMER INC PI COLUMBUS PA OHIO STATE UNIV-DEPT BOTANY, 1735 NEIL AVE, COLUMBUS, OH 43210 USA SN 0002-9122 J9 AM J BOT JI Am. J. Bot. PD MAY PY 2001 VL 88 IS 5 BP 903 EP 909 DI 10.2307/2657042 PG 7 WC Plant Sciences SC Plant Sciences GA 433PL UT WOS:000168768900016 PM 11353715 ER PT J AU McKeown, DA Post, JE AF McKeown, DA Post, JE TI Characterization of manganese oxide mineralogy in rock varnish and dendrites using X-ray absorption spectroscopy SO AMERICAN MINERALOGIST LA English DT Article ID DESERT VARNISH; XANES SPECTROSCOPY; SONORAN DESERT; REFINEMENT; CHEMISTRY; TODOROKITE; MN; BIRNESSITE; BACTERIA; ORIGIN AB X-ray absorption data were collected for a series of varnish and dendrite Mn oxide coatings on rock substrates containing a wide variety of mineralogies exposed to a variety of environments. Near-edge spectra of the coatings indicate that the Mn-oxide phases present have Mn valences between 3+ and 4+, with average Mn valences for the varnishes closer to 4+ than those for the dendrites. Mn EXAFS data and analyses indicate that Mn-oxide structure types for the varnishes range, perhaps continuously, from large tunnel phases, similar to todorokite and romanechite, to layer phases, i.e., birnessite-family. Similar results were found for the dendrite samples, except that the variety of Mn-oxide phases is somewhat larger than those found for the varnishes. No correlations were found between Mn-oxide structure-type within these coatings and the corresponding substrate petrology. C1 Catholic Univ Amer, Vitreous State Lab, Washington, DC 20064 USA. Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. RP McKeown, DA (reprint author), Catholic Univ Amer, Vitreous State Lab, 620 Michigan Ave NE, Washington, DC 20064 USA. NR 41 TC 86 Z9 87 U1 2 U2 22 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 2001 VL 86 IS 5-6 BP 701 EP 713 PG 13 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 430BZ UT WOS:000168554800011 ER PT J AU Doeleman, SS Shen, ZQ Rogers, AEE Bower, GC Wright, MCH Zhao, JH Backer, DC Crowley, JW Freund, RW Ho, PTP Lo, KY Woody, DP AF Doeleman, SS Shen, ZQ Rogers, AEE Bower, GC Wright, MCH Zhao, JH Backer, DC Crowley, JW Freund, RW Ho, PTP Lo, KY Woody, DP TI Structure of Sagittarius A* at 86 GHz using VLBI closure quantities SO ASTRONOMICAL JOURNAL LA English DT Article DE Galaxy : center; galaxies : individual (Sagittarius); techniques : interferometric ID SOURCE SGR-A; NONTHERMAL RADIO-SOURCE; ACCRETING BLACK-HOLE; GALACTIC-CENTER; PROPER-MOTION; COMPACT; POSITION; SPECTRUM; GALAXY; MODEL AB At radio wavelengths, images of the compact radio source Sagittarius A* (Sgr A*) in the Galactic center are scatter broadened with a lambda (2) dependence due to an intervening ionized medium. We present VLBI observations of Sgr A* at 86 GHz using a six station array, including the VLBA antennas at Pie Town, Fort Davis, and Los Alamos, the 12 m antenna at Kitt Peak, and the millimeter arrays at Hat Creek and Owens Valley. To avoid systematic errors due to imperfect antenna calibration, the data were modeled using interferometric closure information. The data are best modeled by a circular Gaussian brightness distribution of FWHM 0.18 +/- 0.02 mas. The data are also shown to be consistent with an elliptical model corresponding to the scattering of a point source. The source structure in the north-south direction, which is less well determined than in the east-west direction because of the limited north-south u-v coverage of the array, is constrained to be less than 0.27 mas by these measurements. These results are consistent with extrapolations of intrinsic structure estimates obtained with VLBI at a 7 mm wavelength, assuming the intrinsic size of Sgr A* has a greater dependence than lambda (0.9) with wavelength. C1 MIT, Haystack Observ, Westford, MA 01886 USA. Natl Astron Observ, Tokyo 1818588, Japan. Acad Sinica, Inst Astron & Astrophys, Taipei 11529, Taiwan. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NRAO, Tucson, AZ 85721 USA. CALTECH, Owens Valley Radio Observ, Big Pine, CA 91125 USA. RP Doeleman, SS (reprint author), MIT, Haystack Observ, Route 40, Westford, MA 01886 USA. NR 35 TC 67 Z9 68 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 MAY PY 2001 VL 121 IS 5 BP 2610 EP 2617 DI 10.1086/320376 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 430UA UT WOS:000168592800023 ER PT J AU Kenyon, SJ Gomez, M AF Kenyon, SJ Gomez, M TI A 3 mu m survey of the Chamaeleon I dark cloud SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; ISM : individual (Chamaeleon I); stars : formation; stars : pre-main-sequence ID T-TAURI STARS; MAIN-SEQUENCE STARS; SPECTRAL ENERGY-DISTRIBUTIONS; X-RAY OBSERVATIONS; CHAMELEON-I; ISOCAM OBSERVATIONS; STELLAR POPULATION; IRAS OBSERVATIONS; EMBEDDED SOURCES; ACCRETION DISKS AB We describe an L-band photometric survey of similar to 0.5 deg(2) of the Chamaeleon I dark cloud. The survey has a completeness limit of L < 11.0. Our survey detects 124 sources, including all known pre-K main-sequence stars with L 11. The fraction of sources with near-IR excess emission is 58% +/- 4% for K = 9-11. Cha I sources have bluer H - K and K - L colors than pre-main-sequence stars in Taurus-Auriga. These sources also have a strong correlation between EW(H alpha) and K - L. Stars with K - L less than or equal to 0.6 have weak H alpha emission; stars with K - L greater than or equal to 0.6 have strong H alpha emission. Because many Cha I sources are heavily reddened, this division between weak emission T Tauri stars and classical T Tauri stars occurs at a redder K - L than in Taurus-Auriga. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Observ Astron Cordoba, RA-5000 Cordoba, Argentina. RP Kenyon, SJ (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. OI Kenyon, Scott/0000-0003-0214-609X NR 58 TC 39 Z9 39 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 MAY PY 2001 VL 121 IS 5 BP 2673 EP 2680 DI 10.1086/320409 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 430UA UT WOS:000168592800029 ER PT J AU Dietrich, M Bender, CF Bergmann, DJ Bills, TE Bochkarev, NG Burenkov, A Gaskell, CM Gutzmer, DD Grove, R Hiller, ME Huchra, JP Klimek, ES Lund, C Merkulova, N Pebley, S Poulsen, MA Pronik, VI Sergeev, SG Sergeeva, EA Shapovalova, AI Vlasyuk, VV Wilkes, B AF Dietrich, M Bender, CF Bergmann, DJ Bills, TE Bochkarev, NG Burenkov, A Gaskell, CM Gutzmer, DD Grove, R Hiller, ME Huchra, JP Klimek, ES Lund, C Merkulova, N Pebley, S Poulsen, MA Pronik, VI Sergeev, SG Sergeeva, EA Shapovalova, AI Vlasyuk, VV Wilkes, B TI A spectroscopic and photometric study of short-timescale variability in NGC 5548 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : Seyfert galaxies galaxies : individual (NGC 5548) ID ACTIVE GALACTIC NUCLEI; BROAD-LINE REGION; RAY SPECTRAL VARIABILITY; SEYFERT 1 GALAXIES; X-RAY; OPTICAL VARIABILITY; MULTIWAVELENGTH OBSERVATIONS; ACCRETION DISKS; NGC 7469; ULTRAVIOLET OBSERVATIONS AB Results of a ground-based optical monitoring campaign on NGC 5548 in June 1998 are presented. The broad-band fluxes (U, B, V), and the spectrophotometric optical continuum flux F lambda (5100 Angstrom) monotonically decreased in flux while the broad-band R and I fluxes and the integrated emission-line fluxes of H alpha and H beta remained constant to within 5%. On June 22, a short continuum are was detected in the broad band fluxes. It had an amplitude of about similar to 18% and it lasted only approximate to 90 min. The broad band fluxes and the optical continuum F lambda (5100 Angstrom) appear to vary simultaneously with the EUV variations. No reliable delay was detected for the broad optical emission lines in response to the EUVE variations. Narrow H beta emission features predicted as a signature of an accretion disk were not detected during this campaign. However, there is marginal evidence for a faint feature at lambda similar or equal to 4962 Angstrom with FWHM similar or equal to 6 Angstrom redshifted by Delta upsilon similar or equal to 1100 km s(-1) with respect to H beta (narrow). C1 Univ Florida, Dept Astron, Bryant Space Sci Ctr 211, Gainesville, FL 32611 USA. Landessternwarte Heidelberg, D-69117 Heidelberg, Germany. Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. Moscow MV Lomonosov State Univ, Sternberg Astron Inst, Moscow 119899, Russia. Russian Acad Sci, Special Astrophys Observ, Nyzknij Arkhyz 369167, Karachaj Cherke, Russia. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Crimean Astrophys Observ, UA-98409 Crimea, Ukraine. Isaac Newton Inst Chile, Crimean Branch, Santiago, Chile. RP Dietrich, M (reprint author), Univ Florida, Dept Astron, Bryant Space Sci Ctr 211, Gainesville, FL 32611 USA. EM dietrich@astro.ufl.edu RI Bender, Chad/D-4719-2012; OI Gaskell, C/0000-0003-4888-2009; Wilkes, Belinda/0000-0003-1809-2364 NR 67 TC 10 Z9 10 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2001 VL 371 IS 1 BP 79 EP 92 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453WY UT WOS:000169942200011 ER PT J AU Castro-Tirado, AJ Sokolov, VV Gorosabel, J Ceron, JMC Greiner, J Wijers, RAMJ Jensen, BL Hjorth, J Toft, S Pedersen, H Palazzi, E Pian, E Masetti, N Sagar, RN Mohan, V Pandey, AK Pandey, SB Dodonov, SN Fatkhullin, TA Afanasiev, VL Komarova, VN Moiseev, AV Hudec, R Simon, V Vreeswijk, P Rol, E Klose, S Stecklum, B Zapatero-Osorio, MR Caon, N Blake, C Wall, J Heinlein, D Henden, A Benetti, S Magazzu, A Ghinassi, F Tommasi, L Bremer, M Kouveliotou, C Guziy, S Shlyapnikov, A Hopp, U Feulner, G Dreizler, S Hartmann, D Boehnhardt, H Paredes, JM Marti, J Xanthopoulos, E Kristen, HE Smoker, J Hurley, K AF Castro-Tirado, AJ Sokolov, VV Gorosabel, J Ceron, JMC Greiner, J Wijers, RAMJ Jensen, BL Hjorth, J Toft, S Pedersen, H Palazzi, E Pian, E Masetti, N Sagar, RN Mohan, V Pandey, AK Pandey, SB Dodonov, SN Fatkhullin, TA Afanasiev, VL Komarova, VN Moiseev, AV Hudec, R Simon, V Vreeswijk, P Rol, E Klose, S Stecklum, B Zapatero-Osorio, MR Caon, N Blake, C Wall, J Heinlein, D Henden, A Benetti, S Magazzu, A Ghinassi, F Tommasi, L Bremer, M Kouveliotou, C Guziy, S Shlyapnikov, A Hopp, U Feulner, G Dreizler, S Hartmann, D Boehnhardt, H Paredes, JM Marti, J Xanthopoulos, E Kristen, HE Smoker, J Hurley, K TI The extraordinarily bright optical afterglow of GRB 991208 and its host galaxy SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; galaxies : general; cosmology : observations ID GAMMA-RAY BURSTS; 28 FEBRUARY 1997; LIGHT CURVES; FIREBALL MODEL; ERROR BOX; PHOTOMETRY; GRB-990123; SUPERNOVA; DISCOVERY; EMISSION AB Broad-band optical observations of the extraordinarily bright optical afterglow of the intense gamma-rag burst GRB 991208 started similar to2.1 days after the event and continued until 4 Apr. 2000. The flux decay constant of the optic al afterglow in the R-band is -2.30 +/- 0.07 up to similar to5 days. which is very likely due to the jet effect. and it is followed by a much steeper decay with constant -3.2 +/- 0.2. the fastest one ever seen in a GRB optical afterglow. A negative detection in several all-sky films taken simultaneously with the er ent. that otherwise would have reached naked eye brightness, implies either a previous additional break prior to similar to2 days after the occurrence of the GRB (as expected from the jet effect) or a maximum, as observed in GRB 970508. The existence of a second break might indicate a steepening in the electron spectrum or the superposition of two events, resembling GRB 000301C. Once the afterglow emission vanished, contribution of a bright underlying supernova was found on the basis of the late-time R-band measurements. but the light curve is not sufficiently well sampled to rule out a dust echo explanation. Our redshift determination of z = 0.706 indicates that GRB 991208 is at 3.7 Gpc (for H-0 = 60 km s(-1) Mpc(-1), Omega (0) = 1 and Lambda (0) = 0), implying an isotropic energy release of 1.15 10(53) erg which may. be relaxed by beaming by a factor >10(2). Precise astrometry indicates that the GRB coincides within 0.2" with the host galaxy, thus supporting a massive star origin. The absolute magnitude of the galaxy is M-B = -18.2, well below the knee of the galaxy luminosity function and we derive a star-forming rate of (11.5 +/- 7.1) M-circle dot yr(-1), which is much larger than the present-day rate in our Galaxy. The quasi simultaneous broad-band photometric spectral energy distribution of the afterglow was determined similar to3.5 day after the burst (Dec. 12.0) implying a cooling frequency ve below the optical band, i.e. supporting a jet model with p = -2.30 as the index of the power-law electron distribution. C1 CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Inst Nacl Invest Agr, LAEFF, E-28080 Madrid, Spain. Russian Acad Sci, Special Astrophys Observ, Nizhnii Arkhyz 357147, Russia. Danish Space Res Inst, Copenhagen, Denmark. Real Inst, Cadiz 11110, Spain. Observ Armada, Secc Astron, Cadiz 11110, Spain. Inst Astrophys, Potsdam, Germany. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Univ Copenhagen, Astron Observ, Copenhagen, Denmark. CNR, Ist Tecnol & Studio Radiaz Extraterr, I-40126 Bologna, Italy. Uttar Pradesh State Observ, Naini Tal 263129, India. Acad Sci Czech Republ, Inst Astron, CS-25165 Ondrejov, Czech Republic. Anton Pannekoehk Inst, Amsterdam, Netherlands. Thuringer Landessternwarte, D-07778 Tautenburg, Germany. Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Tenerife, Spain. Univ Oxford, Oxford AX1 4AU, England. Deutsch Zentrum Luft & Raumfahrt, D-86156 Augsburg, Germany. USN Observ, Flagstaff Stn, AZ USA. Univ Space Res Assoc, Flagstaff Stn, AZ USA. Ctr Galileo Galilei, Canary Isl, Spain. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Inst Radio Astron Millimetr, Grenoble, France. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Nikolaev Univ Observ, UA-327030 Nikolayev, Ukraine. Univ Sternwarte, Munich, Germany. Univ Tubingen, Tubingen, Germany. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. European So Observ, Santiago 19, Chile. Univ Barcelona, Dept Astron & Meteorol, E-08028 Barcelona, Spain. Univ Jaen, Escuela Politecn Super, Dept Fis, Jaen, Spain. Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. Harvard Univ, Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Castro-Tirado, AJ (reprint author), CSIC, Inst Astrofis Andalucia, POB 03004, E-18080 Granada, Spain. EM ajct@laeff.esa.es RI Feulner, Georg/A-1933-2011; Moiseev, Alexey/H-9391-2013; Simon, Vojtech/G-9046-2014; Hudec, Rene/G-9018-2014; Jensen, Brian Lindgren/E-1275-2015; Palazzi, Eliana/N-4746-2015; Shlyapnikov, Aleksey/Q-1646-2016; OI Feulner, Georg/0000-0001-9215-5517; Jensen, Brian Lindgren/0000-0002-0906-9771; Shlyapnikov, Aleksey/0000-0002-2752-2429; Magazzu, Antonio/0000-0003-1259-4371; Benetti, Stefano/0000-0002-3256-0016; Wijers, Ralph/0000-0002-3101-1808; Palazzi, Eliana/0000-0002-8691-7666; Castro-Tirado, A. J./0000-0003-2999-3563; Zapatero Osorio, Maria Rosa/0000-0001-5664-2852; Masetti, Nicola/0000-0001-9487-7740; Paredes, Josep M./0000-0002-1566-9044; Pian, Elena/0000-0001-8646-4858 NR 82 TC 77 Z9 78 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2001 VL 370 IS 2 BP 398 EP 406 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 431BE UT WOS:000168611400008 ER PT J AU Bodo, G Kalkofen, W Massaglia, S Rossi, P AF Bodo, G Kalkofen, W Massaglia, S Rossi, P TI Acoustic waves in a stratified atmosphere - III. Temperature inhomogeneities SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE hydrodynamics; Sun : chromosphere; waves AB In a gravitationally stratified atmosphere, small temperature variations distort the paths of acoustic waves from the rectilinear paths in an isothermal atmosphere. For temperature increasing upward, low-frequency waves near the acoustic cutoff frequency propagating at a given polar angle are refracted towards the vertical direction (focused) and high-frequency waves, away from the vertical (defocused). Similarly, for temperature increasing towards the axis of a vertical cylinder, low-frequency waves are focused and high-frequency waves are defocused. This effect of temperature inhomogeneities may be important for wave propagation in the chromospheric K-2v bright point phenomenon. C1 Osservatorio Astron Torino, I-10025 Pino Torinese, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Turin, Dipartimento Fis Gen, I-10125 Turin, Italy. RP Bodo, G (reprint author), Osservatorio Astron Torino, Strada Osservatorio 20, I-10025 Pino Torinese, Italy. EM bodo@to.astro.it; wolf@cfa.harvard.edu; massaglia@ph.unito.it; rossi@to.astro.it RI Bodo, Gianluigi/F-9223-2012; ROSSI, PAOLA/I-7031-2015; OI Bodo, Gianluigi/0000-0002-9265-4081; ROSSI, PAOLA/0000-0002-0840-4726; massaglia, silvano/0000-0003-1779-7426 NR 8 TC 5 Z9 5 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2001 VL 370 IS 3 BP 1088 EP 1091 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 453WX UT WOS:000169942100032 ER PT J AU Grego, L Carlstrom, JE Reese, ED Holder, GP Holzapfel, WL Joy, MK Mohr, JJ Patel, S AF Grego, L Carlstrom, JE Reese, ED Holder, GP Holzapfel, WL Joy, MK Mohr, JJ Patel, S TI Galaxy cluster gas mass fractions from Sunyaev-Zeldovich effect measurements: Constraints on Omega(M) SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; galaxies : clusters : general; techniques : interferometric ID MEDIUM-SENSITIVITY SURVEY; X-RAY-CLUSTERS; INTRACLUSTER GAS; COOLING FLOWS; MILLIMETER ARRAY; DISTANT CLUSTER; OPTICAL IDENTIFICATIONS; TEMPERATURE PROFILES; BRIGHTEST CLUSTERS; LUMINOUS CLUSTERS AB Using sensitive centimeter-wave receivers mounted on the Owens Valley Radio Observatory and Berkeley-Illinois-Maryland-Association millimeter arrays, we have obtained interferometric measurements of the Sunyaev-Zeldovich (SZ) effect toward massive galaxy clusters. We use the SZ data to determine the pressure distribution of the cluster gas and, in combination with published X-ray temperatures, to infer the gas mass and total gravitational mass of 18 clusters. The gas mass fraction, f(g), is calculated for each cluster and is extrapolated to the fiducial radius r(500) using the results of numerical simulations. The mean f(g) within r(500) is 0.081(-0.011)(+0.009) h(100) (-1)(statistical uncertainty at 68% confidence level, assuming Omega (M), = 0.3, Omega (Lambda) (g)= 0.7). We discuss possible sources of systematic errors in the mean f(g) measurement. We derive an upper limit for Omega (M) from this sample under the assumption that the mass composition of clusters within r(500) reflects the universal mass composition: Omega (M) h less than or equal to Omega (B)/f(g). The gas mass fractions depend on cosmology through the angular diameter distance and the r(500) correction factors. For a flat universe (Omega (Lambda) equivalent to 1 - Omega (M)) and h = 0.7, we find the measured gas mass fractions are consistent with Omega (M) < 0.40, at 68% confidence. Including estimates of the baryons contained in galaxies and the baryons which failed to become bound during the cluster formation process, we find (M) similar to 0.25. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Grego, L (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Holzapfel, William/I-4836-2015 NR 79 TC 128 Z9 129 U1 0 U2 2 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 MAY PY 2001 VL 552 IS 1 BP 2 EP 14 DI 10.1086/320443 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 434EX UT WOS:000168803100002 ER PT J AU Wang, XH Loeb, A AF Wang, XH Loeb, A TI Emission from bow shocks of beamed gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; shock waves ID COSMOLOGICAL FIREBALL MODEL; SNR RX J1713.7-3946; 28 FEBRUARY 1997; LIGHT CURVES; OPTICAL AFTERGLOW; X-RAYS; SUPERNOVAE; DISCOVERY; SPECTRA; JET AB Beamed gamma-ray burst (GRB) sources produce a bow shock in their gaseous environment. The emitted flux from this bow shock may dominate over the direct emission from the jet for lines of sight that are outside the angular radius of the jet emission, Theta (b). The event rate for these lines of sight is increased by a factor of similar to 260(Theta (b)/5 degrees)(-2). For typical GRB parameters, we find that the bow shock synchrotron emission from a jet of half-angle similar to5 degrees is visible out to tens of megaparsecs in the radio and hundreds of megaparsecs in the X-ray. If GRBs are linked to supernovae (SNe), studies of peculiar SNe in the local universe should reveal this nonthermal bow shock emission for weeks to months following the explosion. Roughly one out of similar to 10(3)(Theta (b)/5 degrees)(2) SNe should display nonthermal bow shock emission, assuming a SN rate of similar to (100 yr)(-l) per L-* galaxy. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Wang, XH (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 59 TC 6 Z9 7 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY PY 2001 VL 552 IS 1 BP 49 EP 56 DI 10.1086/320451 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 434EX UT WOS:000168803100006 ER PT J AU Ball, GH Narayan, R Quataert, E AF Ball, GH Narayan, R Quataert, E TI Spectral models of convection-dominated accretion flows SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; convection; X-rays : general ID SAGITTARIUS-A-ASTERISK; BLACK-HOLE; GALACTIC NUCLEI; DISKS; LUMINOSITY; TRANSITIONS; QUIESCENCE AB For small values of the dimensionless viscosity parameter, namely alpha less than or similar to0.1, the dynamics of nonradiating accretion hows is dominated by convection; convection strongly suppresses the accretion of matter onto the central object and transports a luminosity similar to (10(-3)-10(-2))Mc(2) from Small to large radii in the flow. A fraction of this convective luminosity is likely to be radiated at large radii via thermal bremsstrahlung emission. We show that this leads to a correlation between the frequency of maximal bremsstrahlung emission and the luminosity of the source, v(peak) proportional to L-2/3. Accreting black holes with X-ray luminosities 10(-4)L(Edd) greater than or similar toL(x) (0.5-10 keV) greater than or similar to 10(-7)L(Edd) are expected to have hard X-ray spectra, with photon indices Gamma similar to 2, and sources with L-x less than or similar to 10(-9)L(Edd) are expected to have soft spectra, with Gamma similar to 3.5. This is testable with Chandra and XMM. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Inst Adv Study, Princeton, NJ 08540 USA. RP Ball, GH (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Narayan, Ramesh/0000-0002-1919-2730 NR 39 TC 59 Z9 59 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY PY 2001 VL 552 IS 1 BP 221 EP 226 DI 10.1086/320465 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 434EX UT WOS:000168803100022 ER PT J AU Morales, C Orozco, V Gomez, JF Trapero, J Talavera, A Bowyer, S Edelstein, J Korpela, E Lampton, M Drake, JJ AF Morales, C Orozco, V Gomez, JF Trapero, J Talavera, A Bowyer, S Edelstein, J Korpela, E Lampton, M Drake, JJ TI Far-ultraviolet spectra of B stars near the ecliptic SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : atmospheres; stars : early-type; ultraviolet : stars ID MAIN-SEQUENCE STARS; HOT STARS; CHEMICAL EVOLUTION; INTERSTELLAR EXTINCTION; ENERGY-DISTRIBUTION; ORION ASSOCIATION; CATALOG; OXYGEN; UVBY; FLUX AB Spectra of B stars in the wavelength range of 911-1100 Angstrom have been obtained with the Espectrografo Ultravioleta de Radiacion Difusa (EURD) spectrograph on board the Spanish satellite MINISAT-01 with similar to5 Angstrom spectral resolution. International Ultraviolet Explorer (IUE) spectra of the same stars have been used to normalize Kurucz models to the distance, reddening, and spectral type of the corresponding star. The comparison of eight main-sequence stars studied in detail (alpha Vir, lambda Tau, lambda Tau, tau Tau, alpha Leo, zeta Lib, theta Oph, and sigma Sgr) shows agreement with Kurucz models, but observed fluxes are 10%-40% higher than the models in most cases. The difference in flux between observations and models is higher in the wavelength range between Ly alpha and Ly beta. We suggest that Kurucz models underestimate the far-ultraviolet (FUV) flux of main-sequence B stars between these two Lyman lines. Computation of flux distributions of line-blanketed model atmospheres including non-LTE effects suggests that this flux underestimate could be due to departures from LTE, although other causes cannot be ruled out. We found that the common assumption of solar metallicity for young disk stars should be made with care, since small deviations can have a significant impact on FUV model fluxes. Two peculiar stars (rho Leo and epsilon Aqr) and two emission-line stars (epsilon Cap and pi Aqr) were also studied. Of these, only a Aqr has a flux in agreement with the models. The rest have strong variability in the IUE range and/or uncertain reddening, which makes the comparison with models difficult. C1 Inst Nacl Tecn Aeroespacial, Lab Astrofis Espacial & Fis Fundamental, E-28080 Madrid, Spain. Univ SEK, E-40003 Segovia, Spain. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Morales, C (reprint author), Inst Nacl Tecn Aeroespacial, Lab Astrofis Espacial & Fis Fundamental, Apdo Correos 50727, E-28080 Madrid, Spain. RI Gomez, Jose Francisco/D-8392-2016; OI Gomez, Jose Francisco/0000-0002-7065-542X; Korpela, Eric/0000-0001-8078-9395 NR 53 TC 8 Z9 8 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 MAY PY 2001 VL 552 IS 1 BP 278 EP 288 DI 10.1086/320439 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 434EX UT WOS:000168803100028 ER PT J AU Vestergaard, M Wilkes, BJ AF Vestergaard, M Wilkes, BJ TI An empirical ultraviolet template for iron emission in quasars as derived from I Zwicky 1 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE galaxies : active; galaxies : individual (I Zw 1); galaxies : Seyfert; methods : data analysis; quasars : emission lines ID ACTIVE GALACTIC NUCLEI; LINE SEYFERT-1 GALAXIES; HUBBLE-SPACE-TELESCOPE; RADIATIVE TRANSITION-PROBABILITIES; LOW-IONIZATION LINES; FE-II; ATOMIC DATA; STELLAR OBJECTS; RADIO-LOUD; PHYSICAL CONDITIONS AB We present an empirical template spectrum suitable for fitting and subtracting/studying the Fe II and Fe III emission lines in the rest frame ultraviolet spectra of quasars and active galactic nuclei, the first empirical ultraviolet iron template to cover the full range of 1250-3090 Angstrom. Iron emission is often a severe contaminant in optical-ultraviolet spectra of active galactic nuclei and quasars. Its presence complicates and limits the accuracy of measurements of both strong and weak emission lines and the continuum emission, affecting studies of line and continuum interrelations, the ionization structure, and elemental abundances in active galaxies and quasars. Despite the wealth of work on modeling the quasar Fe II emission and the need to account for this emission in observed quasar spectra, there is no ultraviolet template electronically available to aid this process. The iron template we present is based on Hubble Space Telescope spectra of the narrow line Seyfert 1 galaxy, I Zwicky 1 (I Zw 1, z = 0.061). The intrinsic narrow lines (greater than or similar to 900 km s(-1)) of this source and its rich iron spectrum make the template particularly suitable for use with most active galactic nuclei and quasar spectra. The iron emission spectrum, the line identifications, and the measurements of absorption and emission lines are presented and compared with the work of Laor et al. Comments on each individual line feature and the line fitting are available in Appendix A. The methods used to develop and apply the template are also described. We illustrate the application of the derived Fe II and Fe III templates by fitting and subtracting iron emission from the spectra of four high-redshift quasars and of the nearby quasar, 3C 273, confirming their general applicability to active galaxies despite the somewhat unusual properties of I Zw 1. We briefly discuss the small discrepancies between the observed iron emission of these quasars and the ultraviolet template, and compare the template with previously published ones. We discuss the advantages and limitations of the UV Fe II and Fe III templates and of the template fitting method. We conclude that the templates work sufficiently well to be a valuable and important tool for eliminating and studying the iron emission in active galaxies, at least until accurate theoretical iron emission models are developed. The Si IV+O IV] lambda 1400 feature in I Zw 1 is clearly strong relative to C IV lambda 1549, and C IV and C III] lambda 1909 are both relatively weak. This may partially be due to the higher densities and lower ionization parameter prevailing in narrow line Seyfert 1 galaxies and to the big blue bump shifting toward lower energies in more luminous Seyferts, such as I Zw 1. In I Zw 1 the narrow line width reveals that C III] is heavily blended with Si III] lambda 1892, Al III lambda lambda 1854,1863, and Fe III transitions. This suggests that the C III] line strength and width may be overestimated in many quasar line studies where the lines are broader and deblending is not possible. This affects density estimates of the broad line region. Photoionization modeling, including all these line features, and subsequent fitting to the spectra are required to estimate the true C III] strength. We also argue, based on earlier work, that (strong) iron emission may be connected with high densities and associated with outflows. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Copenhagen Univ Observ, Niels Bohr Inst Astron Phys & Geophys, DK-2100 Copenhagen O, Denmark. RP Vestergaard, M (reprint author), Ohio State Univ, Dept Astron, 140 W 18th Ave, Columbus, OH 43210 USA. RI Vestergaard, Marianne/M-5247-2014; OI Vestergaard, Marianne/0000-0001-9191-9837; Wilkes, Belinda/0000-0003-1809-2364 NR 126 TC 234 Z9 236 U1 0 U2 4 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 MAY PY 2001 VL 134 IS 1 BP 1 EP 33 DI 10.1086/320357 PN 1 PG 33 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 432TG UT WOS:000168711300001 ER PT J AU Forster, K Green, PJ Aldcroft, TL Vestergaard, M Foltz, CB Hewett, PC AF Forster, K Green, PJ Aldcroft, TL Vestergaard, M Foltz, CB Hewett, PC TI Emission line properties of the large bright quasar survey SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : active; quasars : emission lines; quasars : general; ultraviolet : galaxies ID ACTIVE GALACTIC NUCLEI; BROAD-ABSORPTION-LINE; LOW-REDSHIFT QSOS; FE-II EMISSION; EQUATORIAL FIELDS; STATISTICAL-METHODS; ASTRONOMICAL DATA; RADIO PROPERTIES; STELLAR OBJECTS; UPPER LIMITS AB We present measurements of the optical/UV emission lines for a large homogeneous sample of 993 quasars from the Large Bright Quasar Survey. Our largely automated technique accounts for continuum breaks and galactic reddening, and we perform multicomponent fits to emission line profiles, including the effects of blended iron emission, and of absorption lines both galactic and intrinsic. Here we describe the fitting algorithm and present the results of line fits to the LBQS sample, including upper limits to line equivalent widths when warranted. The distribution of measured line parameters, principally W-lambda and FWHM, are detailed for a variety of lines, including upper limits. We thus initiate a large-scale investigation of correlations between the high-energy continuum and emission lines in quasars, to be extended to complementary samples using similar techniques. High-quality, reproducible measurements of emission lines for uniformly selected samples will advance our understanding of active galaxies, especially in a new era of large surveys selected by a variety of complementary methods. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Arizona, Multiple Mirror Telescope Observ, Tucson, AZ 85721 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Forster, K (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Vestergaard, Marianne/M-5247-2014 OI Vestergaard, Marianne/0000-0001-9191-9837 NR 61 TC 66 Z9 66 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2001 VL 134 IS 1 BP 35 EP 51 DI 10.1086/320362 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 432TG UT WOS:000168711300002 ER PT J AU Navascues, DBY Stauffer, JR Briceno, S Patten, B Hambly, NC Adams, JD AF Navascues, DBY Stauffer, JR Briceno, S Patten, B Hambly, NC Adams, JD TI Very low-mass stars and brown dwarfs of the young open cluster IC 2391 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE open clusters and associations : individual (IC 2391); stars : low-mass, brown dwarfs ID ALPHA-PERSEI; STANDARD STARS; MAIN-SEQUENCE; IC-2391; MEMBERSHIP AB We have identified a large sample of probable low-mass members of the young open cluster IC 2391 based on optical (VRIZ) and infrared photometry. Our sample includes 50 probable members (JHK(s)) and 82 possible members, both very low-mass stars and brown dwarfs. We also provide accurate positions for these stars and brown dwarf candidates derived from red UK Schmidt plates measured using the microdensitometer SuperCOSMOS. Assuming an age of 53 Myr, we estimate that we have reached a mass of 0.025 M-., if the identified objects are indeed members of IC 2391. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Ctr Invest Astron, Merida 5101A, Venezuela. Univ Edinburgh, Royal Observ, Inst Astron, Edinburgh EH9 3HJ, Midlothian, Scotland. Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA. RP Navascues, DBY (reprint author), Univ Autonoma Madrid, Dept Fis Teor, C-11, E-28049 Madrid, Spain. EM barrado@pollux.ft.uam.es; jstauffer@cfa.harvard.edu; briceno@cida.ve; bpatten@cfa.harvard.edu; nch@roe.ac.uk; adams@pegasus.astro.umass.edu RI Barrado Navascues, David/C-1439-2017 OI Barrado Navascues, David/0000-0002-5971-9242 NR 29 TC 42 Z9 43 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2001 VL 134 IS 1 BP 103 EP 114 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 432TG UT WOS:000168711300005 ER PT J AU Kling, R Schnabel, R Griesmann, U AF Kling, R Schnabel, R Griesmann, U TI Accurate lifetimes and absolute transition rates for ultraviolet transitions from 3d(5)((4)G) 4p and 3d(5)(4P) 4p levels in MN II SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; methods : laboratory; ultraviolet : general ID SPECTROMETER RESPONSE CALIBRATION; LASER-INDUCED-FLUORESCENCE; VACUUM-ULTRAVIOLET; BRANCHING RATIOS; ARGON; BEAM AB A recently developed, laser-induced fluorescence technique was used to measure the lifetimes of 14 3d(5)((4)G)4p and 3d(5)(P-4)4p levels in the Mn+ ion. Branching fractions for electric dipole transitions from these levels were measured with a vacuum ultraviolet Fourier transform spectrometer, using a hollow-cathode lamp and a Penning discharge source. Based on these new measurements, absolute electric dipole transition rates for about 170 spectral lines in the ultraviolet and vacuum ultraviolet were determined. The uncertainty of the transition rates is less than 5% for the strong transitions. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Hannover, Inst Atom & Mol Phys, Abt Plasmaphys, D-30167 Hannover, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kling, R (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 20 TC 19 Z9 19 U1 1 U2 3 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 MAY PY 2001 VL 134 IS 1 BP 173 EP 178 DI 10.1086/320366 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 432TG UT WOS:000168711300010 ER PT J AU Condit, R Robinson, WD Ibanez, R Aguilar, S Sanjur, A Martinez, R Stallard, RF Garcia, T Angehr, GR Petit, L Wright, SJ Robinson, TR Heckadon, S AF Condit, R Robinson, WD Ibanez, R Aguilar, S Sanjur, A Martinez, R Stallard, RF Garcia, T Angehr, GR Petit, L Wright, SJ Robinson, TR Heckadon, S TI The status of the Panama Canal watershed and its biodiversity at the beginning of the 21st century SO BIOSCIENCE LA English DT Article ID BARRO-COLORADO ISLAND; POPULATION DECLINES; PUERTO-RICO; FOREST; CONSERVATION; LANDSLIDES; MORTALITY C1 Smithsonian Trop Res Inst, APO, AA 34002 USA. Auburn Univ, Dept Biol Sci, Auburn, AL 36849 USA. Autoridad Nacl Ambiente, Ancon, Panama. Smithsonian Trop Res Inst, Ancon, Panama. Univ Panama, Dept Geog, Panama City, Panama. Panama Canal Author, Miami, FL 33102 USA. US Geol Survey, Boulder, CO 80303 USA. Smithsonian Inst, Natl Zool Pk, Migratory Bird Ctr, Washington, DC 20008 USA. RP Condit, R (reprint author), Smithsonian Trop Res Inst, APO, AA 34002 USA. RI Wright, Stuart/M-3311-2013; Stallard, Robert/H-2649-2013 OI Wright, Stuart/0000-0003-4260-5676; Stallard, Robert/0000-0001-8209-7608 NR 46 TC 43 Z9 45 U1 2 U2 11 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD MAY PY 2001 VL 51 IS 5 BP 389 EP 398 DI 10.1641/0006-3568(2001)051[0389:TSOTPC]2.0.CO;2 PG 10 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 442PJ UT WOS:000169293900011 ER PT J AU McCarthy, MC Thaddeus, P AF McCarthy, MC Thaddeus, P TI Microwave and laser spectroscopy of carbon chains and rings SO CHEMICAL SOCIETY REVIEWS LA English DT Review ID DIFFUSE INTERSTELLAR BANDS; ABSORPTION SPECTROSCOPY; RHOMBOIDAL SIC3; DIPOLE-MOMENT; GROUND-STATE; SPECTROMETER; SPECTRUM; PREDICTIONS; MOLECULES; RADICALS AB The interstellar gas and the gas ejected into space by cool stars are now known to contain a rich collection of molecules. Most of these are organic compounds, some of which are familiar to the terrestrial chemist and can be found in a standard chemical stockroom, but many are entirely new molecules which have been detected and identified in space for the first time. Most of the nearly 100 polyatomic molecules so far detected in astronomical sources by radio telescopes are highly unsaturated carbon chains, a structure which is explosively unstable at even moderate density, and therefore difficult to study spectroscopically on Earth. For this reason laboratory detection has until quite recently lagged well behind the astronomical discovery of many carbon chains. The application of Fourier transform microwave and laser cavity ringdown absorption spectroscopy to supersonic molecular beams has largely overcome this difficulty, yielding in this laboratory during the past four years more than 75 new reactive molecules, including long carbon chains, chains attached to rings, silicon-carbon rings, and several protonated molecular ions. All or nearly all of these are candidates for astronomical discovery because they are highly polar and are close in structure and composition to molecules which have already been discovered in space. Seven have already been found with large radio telescopes, six as a result of the laboratory work described here. These discoveries include the largest interstellar molecule HC11N, the largest ring, SiC3, and the largest positive ion, HC3NH+. One of our most interesting recent laboratory discoveries is the laser detection of a strong molecular band at lambda 4429, the wavelength of the strongest and best known diffuse interstellar band. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP McCarthy, MC (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI McCarthy, Michael/0000-0001-9142-0008 NR 41 TC 76 Z9 79 U1 1 U2 15 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0306-0012 J9 CHEM SOC REV JI Chem. Soc. Rev. PD MAY PY 2001 VL 30 IS 3 BP 177 EP 185 DI 10.1039/b006648f PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 428PT UT WOS:000168470600004 ER PT J AU Brumfield, RT Braun, MJ AF Brumfield, RT Braun, MJ TI Phylogenetic relationships in bearded manakins (Pipridae : Manacus) indicate that male plumage color is a misleading taxonomic marker SO CONDOR LA English DT Article DE Andes; biogeography; hybrid zone; Manacus; manakins; protein electrophoresis; systematics ID MOLECULAR PERSPECTIVE; TREES; BIRDS; DIVERSIFICATION; SPECIATION; PARSIMONY; AVES AB The piprid genus Manacus is composed of four allospecies that are readily distinguishable by differences in male plumage color. Electrophoretic data for two populations of each of the four forms plus seven outgroup piprid taxa were collected from 32 isozyme loci and used to infer phylogenetic relationships. Each Manacus form was monophyletic, with the exception of M. manacus, in which the trans-Andean (west of the Andes) population was sister to M. vitellinus, rather than to its conspecific cis-Andean (east of the Andes) population. This controversial relationship, supported by the synapomorphic allele PGM-2(b) as well as allele frequencies at ADA, GOT-1 and LGG, is consistent with general biogeographic patterns in the region, but indicates that male plumage color is an unreliable taxonomic marker. Reconstruction of male plumage color on the tree confirms that gold plumage is a derived state in M. vitellinus, a finding consistent with the possibility that gold plumage is an evolutionary novelty in vitellinus which has spread recently under positive selection. Among piprids, there was strong support for a group composed of Antilophia, Chiroxiphia, and Corapipo, and for a group composed of Pipra mentalis, P. fasciicauda, and Dixiphia pipra. Manacus is more closely related to the P. mentalis + P. fasciicauda + D. pipra group. The isozymes supported Lepidothrix as the basal taxon of those examined. C1 Smithsonian Inst, Natl Museum Nat Hist, Lab Mol Systemat, MRC 534, Washington, DC 20560 USA. Univ Maryland, Dept Biol, College Pk, MD 20742 USA. RP Brumfield, RT (reprint author), Univ Washington, Dept Zool, Box 351800, Seattle, WA 98195 USA. EM brumfld@lms.si.edu RI Brumfield, Robb/K-6108-2015 OI Brumfield, Robb/0000-0003-2307-0688 NR 34 TC 22 Z9 24 U1 1 U2 8 PU COOPER ORNITHOLOGICAL SOC PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0010-5422 J9 CONDOR JI Condor PD MAY PY 2001 VL 103 IS 2 BP 248 EP 258 DI 10.1650/0010-5422(2001)103[0248:PRIBMP]2.0.CO;2 PG 11 WC Ornithology SC Zoology GA 430HZ UT WOS:000168569600005 ER PT J AU Isler, ML Isler, PR Whitney, BM Walker, B AF Isler, ML Isler, PR Whitney, BM Walker, B TI Species limits in antbirds: The Thamnophilus punctatus complex continued SO CONDOR LA English DT Article DE species limits; Thamnophilus punctatus; vocal characters AB In a previous study (Isler et al. 1997) we examined species limits in the Thamnophilus punctatus complex of the Neotropics. We recommended that six taxa be considered species, but were unable to make recommendations regarding two morphologically distinct and geographically restricted taxa, leucogaster and huallagae, due to the lack of vocal recordings which were essential to our methodology. Analysis of newly obtained recordings has found that vocal differences support the separation at the species level of leucogaster and huallagae from five of the six species in the complex (T. atrinucha, T. stictocephalus, T. sticturus, T. pelzelni, and T. ambiguus). However, leucogaster, and huallagae could not be distinguished vocally from each other nor from nominate punctatus to an extent that supported species status, and they are retained as subspecies under our recommended guidelines (Isler et al. 1998. 1999). The Thamnophilus punctatus complex affords an interesting: opportunity for future molecular studies that compare the genetic distances among populations that have differentiated vocally and those that have not. The question of species status of leucogaster and huallagae is pressing because the ranges of both taxa are limited to sub-Andean basins in northwestern Peru and southwestern Ecuador that increasingly are under cultivation. C1 Smithsonian Inst, Natl Museum Nat Hist, Div Birds, Washington, DC 20560 USA. Louisiana State Univ, Museum Nat Sci, Baton Rouge, LA 70803 USA. Manu Expedit, Cusco, Peru. RP Isler, ML (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Div Birds, Washington, DC 20560 USA. NR 13 TC 8 Z9 8 U1 1 U2 3 PU COOPER ORNITHOLOGICAL SOC PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0010-5422 J9 CONDOR JI Condor PD MAY PY 2001 VL 103 IS 2 BP 278 EP 286 DI 10.1650/0010-5422(2001)103[0278:SLIATT]2.0.CO;2 PG 9 WC Ornithology SC Zoology GA 430HZ UT WOS:000168569600008 ER PT J AU Chu, M AF Chu, M TI Vocal mimicry in distress calls of Phainopeplas SO CONDOR LA English DT Article DE distress calls; Phainopepla nitens; Phaineopeplas; vocal mimicry ID SPARROWS AVES-FRINGILLIDAE; ALARM CALLS; RESPONSES; SWAMP; SONG AB Phainopeplas (Phainopepla nitens) utter contact calls, loud distress screams, and 37 other distinguishable vocalizations when captured, including imitations of at least 12 species. In southern California, Phainopeplas captured in the desert and coastal woodlands imitated species from both regions, suggesting that individuals occupy both habitats during the year and have an extended period of learning that spans the period of time when they move between regions. There was no significant difference in the number of calls imitated based on sex, male age, or habitat. A high percentage of Phainopeplas in both desert and coastal woodlands imitated Red-tailed Hawks (Buteo jamaicensis) and Northern Flickers (Colaptes auratus), whereas the use of other species' calls varied with habitat. Phainopeplas did not simply imitate the calls of the most abundant species or those that were most vocal. C1 Univ Calif Berkeley, Museum Vertebrate Zool, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Integrat Biol, Berkeley, CA 94720 USA. RP Chu, M (reprint author), Smithsonian Inst, Natl Zool Pk, 3001 Connecticut Ave NW, Washington, DC 20008 USA. NR 17 TC 13 Z9 14 U1 3 U2 7 PU COOPER ORNITHOLOGICAL SOC PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0010-5422 J9 CONDOR JI Condor PD MAY PY 2001 VL 103 IS 2 BP 389 EP 395 DI 10.1650/0010-5422(2001)103[0389:VMIDCO]2.0.CO;2 PG 7 WC Ornithology SC Zoology GA 430HZ UT WOS:000168569600020 ER PT J AU Castillo, A Lessios, HA AF Castillo, A Lessios, HA TI Lobster fishery by the Kuna Indians in the San Blas region of Panama (Kuna Yala) SO CRUSTACEANA LA English DT Article ID CARIBBEAN SPINY LOBSTER; MITOCHONDRIAL-DNA VARIATION; PANULIRUS-ARGUS; MASS MORTALITY; DIADEMA-ANTILLARUM; FLORIDA; HABITAT; MEXICO; SIZE AB The San Bias archipelago along the Atlantic coast of Panama is inhabited exclusively by Kuna Indians, who maintain the rights to exploit fishery resources in the area. Exportation of the spiny lobster, Pa,Panulirus argus, to Panama City constitutes one of the major sources of income for the Kuna economy. No published data exist on either the magnitude of the fishery or the life history and population dynamics of P. argus anywhere in Panama. We monitored P. argus export in two areas of Kuna Yala over a period spanning 16 months. We gathered data on weight, length, sex, and reproductive state of all lobsters comprising the catch of each day. Overall, the sex ratio of P. argus in the San Bias was nor significantly different from unity. However, there was a significant excess of fi males among smaller size classes (< 105 mm carapace length, CL), and of males among larger ones. The size of fil st reproduction for female P. argus in Kuna Yala is 67 mm CL as defined by the smallest size class including females with eggs or spermatophores, and 73 mm CL as defined by the smallest size class in which > 20% of the females carried eggs. Reproductive females were present during all 9 months covered by our monitoring, with no clear peak in their proportion, indicating year-round reproduction. Average measured daily export of P. argus to Panama City was 11.7 Kg at one locality and 20.1 kg (in one of three outlets) at the other. Total estimated annual export was 18 t from these two localities and 92.48 t from the entire San Bias region. At 1998 prices, the total income to the Kuna nation from lobster export was estimated as US$ 620,388.00. Median carapace length of exported lobsters (83 mm in one locality, 77 mm in the other) was only slightly larger than the size at first sexual maturity. Thus, slightly less than half of the export consists of pre-reproductive individuals. However, because Kunas only fish for lobster by fret-diving during the day, there is a sanctuary for lobster in depths > 20 m. Removal of small P. argus individuals and harvesting of shallow coral for the construction of sea walls are the greatest threats to the resource. As of 1998, the estimated yield per km(2) (67 kg) was relatively high compared with other areas of the Caribbean. considering that no traps, nets, or SCUBA diving are employed in the fishery. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Lessios, HA (reprint author), Smithsonian Trop Res Inst, Box 2072, Balboa, Panama. NR 46 TC 7 Z9 7 U1 2 U2 7 PU BRILL ACADEMIC PUBLISHERS PI LEIDEN PA PLANTIJNSTRAAT 2, P O BOX 9000, 2300 PA LEIDEN, NETHERLANDS SN 0011-216X J9 CRUSTACEANA JI Crustaceana PD MAY PY 2001 VL 74 BP 459 EP 475 DI 10.1163/156854001750243045 PN 5 PG 17 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 450CE UT WOS:000169723300004 ER PT J AU Lessios, HA Kessing, BD Pearse, JS AF Lessios, HA Kessing, BD Pearse, JS TI Population structure and speciation in tropical seas: Global phylogeography of the sea urchin Diadema SO EVOLUTION LA English DT Review DE ATPase; biogeography; cytochrome oxidase I; gene flow; mitochondrial DNA; ocean barriers; phylogeny; sea urchins; speciation ID INDO-WEST PACIFIC; STARFISH ACANTHASTER-PLANCI; HIGH-DISPERSAL STARFISH; MITOCHONDRIAL-DNA; GENETIC-STRUCTURE; INDIAN-OCEAN; EASTERN PACIFIC; AGULHAS CURRENT; NUCLEOTIDE SUBSTITUTIONS; EVOLUTIONARY TREES AB The causes of speciation in the sea are rarely obvious, because geographical barriers are not conspicuous and dispersal abilities or marine organisms, particularly those of species with planktonic larvae, are hard to determine. The phylogenetic relations of species in cosmopolitan genera can provide information on the likely mode of their formation. We reconstructed the phylogeny of the pantropical and subtropical sea urchin genus Diadema, using sequences of mitochondrial DNA from 482 individuals collected around the world, to determine the efficacy of barriers to gene flow and to ascertain the history of possible dispersal and vicariance events that led to speciation. We also compared 22 isozyme loci between all described species except D. palmeri. The mitochondrial DNA data show that the two deepest lineages are found in the Indian and West Pacific Oceans. (Indo-Pacific) Diadema setosum diverged first from all other extant Diadema, probably during the initiation of wide fluctuations in global sea levels in the Miocene. The D. setosum clade then split 3-5 million years ago into two clades, one found around the Arabian Peninsula and the other in the Indo-West. Pacific. On the lineage leading to the other species of Diadema, the deepest branch is composed of D. palmeri. apparently separated when the climate of New Zealand became colder and other tropical echinoids at these islands went extinct. The next lineage to separate is composed of a currently unrecognized species of Diadema that is found at Japan and the Marshall Islands. Diadema mexicanum in the eastern Pacific separated next, whereas D. paucispinum. D. savignyi, and D. antillarum from the western and central Atlantic, and (as a separate clade) D. antillarum from the eastern Atlantic form a shallow polytomy. Apparently, Indo-Pacific populations of Diadema maintained genetic contact with Atlantic ones around the southern tip of Africa for some time after the Isthmus of Panama was complete. Diadema paucispinum contains two lineages: D. paucispinum sensu stricto is not limited to Hawaii as previously thought, but extends to Easter Island, Pitcairn, and Okinawa; A second mitochondrial clade of D. paucispinum extends from East Africa and Arabia to the Philippines and New Guinea. A more recent separation between West Indian Ocean and West Pacific populations was detected in D. setosum. Presumably, these genetic discontinuities are the result of water flow restrictions in the straits between northern Australia and Southeast Asia during Pleistocene episodes of low sea level. Diadema savignyi is characterized by high rates of gene how from Kiribati in the central Pacific all the way to the East African Coast. In the Atlantic, there is a biogeographic barrier between the Caribbean and Brazil, possibly caused by fresh water outflow from the Amazon and the Orinoco Rivers. Diadema antillarum populations of the central Atlantic islands of Ascension and St. Helena are genetically isolated and phylogenetically derived from Brazil. Except for its genetic separation by the mid-atlantic barrier, Diadema seems to have maintained connections through potential barriers to dispersal (including the Isthmus of Panama) more recently than did Eucidaris or Echinometra, two other genera of sea urchins in which phylogeography has been studied. Nevertheless, the mtDNA phylogeography of Diadema includes all stages expected from models of allopatric differentiation. There are anciently separated clades that now overlap in their geographic distribution, clades isolated in the periphery of the genus range that have remained in the periphery, clades that may have been isolated in the periphery but have since spread towards the center, closely related clades on either side of an existing barrier, and closely related monophyletic entities on either side of an historical barrier that have crossed the former barrier line, but have not attained genetic equilibrium. Except for D. paucispinum and D. savignyi, in which known hybridization may have lodged mtDNA from one species into the genome of the other, closely related clades are always allopatric, and only distantly related ones overlap geographically. Thus, the phylogenetic history and distribution of extant species of Diadema is by and large consistent with allopatric speciation. C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Calif Santa Cruz, Inst Marine Sci, Joseph M Long Marine Lab, Santa Cruz, CA 95060 USA. RP Lessios, HA (reprint author), Smithsonian Trop Res Inst, Unit 0948,APO, APO, AA 34002 USA. NR 167 TC 267 Z9 277 U1 6 U2 75 PU SOC STUDY EVOLUTION PI LAWRENCE PA 810 E 10TH STREET, LAWRENCE, KS 66044 USA SN 0014-3820 J9 EVOLUTION JI Evolution PD MAY PY 2001 VL 55 IS 5 BP 955 EP 975 DI 10.1554/0014-3820(2001)055[0955:PSASIT]2.0.CO;2 PG 21 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 444MK UT WOS:000169403100012 PM 11430656 ER PT J AU Bowen, BW Bass, AL Rocha, LA Grant, WS Robertson, DR AF Bowen, BW Bass, AL Rocha, LA Grant, WS Robertson, DR TI Phylogeography of the trumpetfishes (Aulostomus): Ring species complex on a global scale SO EVOLUTION LA English DT Review DE biogeography; cytochrome b; dispersal; marine fish; mitochondrial DNA; population structure; vicariance ID CORAL-REEF FISH; MITOCHONDRIAL-DNA; GENE FLOW; MARINE FISHES; ENSATINA-ESCHSCHOLTZII; POPULATION HISTORIES; OCEAN CURRENTS; CONTROL REGION; DIVERGENCE; EVOLUTION AB The distribution of circumtropical marine species is limited by continental boundaries, cold temperate conditions, and oceanic expanses, but some of these barriers are permeable over evolutionary time scales. Sister taxa that evolved in separate ocean basins can come back into contact, and the consequences of this renewed sympatry may be a key to understanding evolutionary processes in marine organisms. The circumtropical trumpetfishes (Au lostomus) include a West Atlantic species (Pi. maculatus), an Indian-Pacific species (A. chinensis), and an East Atlantic species (A. strigosus) that may be the product of a recent invasion from the Indian Ocean. To resolve patterns of divergence and speciation, we surveyed 480 bp of mitochondrial DNA cytochrome b in 196 individuals from 16 locations. Based on a conventional molecular clock of 2% sequence divergence per million years, the deepest partitions in a neighbor-joining tree (d = 0.063-0.082) are consistent with separation of West Atlantic and Indian-Pacific species by the Isthmus of Panama, 3-4 million years ago. By the same criteria, trumpetfish in the East Atlantic were isolated from the Indian Ocean about 2.5 million years ago (d = 0.044-0.054), coincident with the advent of glacial cycles and cold-water upwelling around South Africa. Continental barriers between tropical oceans have only rarely been surmounted by trumpetfishes, but oceanic barriers do not appear to be substantial, as indicated by weak population partitioning (phi (ST) = 0.093) in A. chinensis across the Indian and Pacific Oceans. Finally, morphological and mitochondrial DNA data indicate hybridization of A. strigosus and A. maculatus in Brazil. After 3-4 million years and a globe-spanning series of vicariant and dispersal events, trumpetfish lineages have come back into contact in the southwest Atlantic and appear to be merging. This ring species phenomenon may occur in a broad array of marine organisms, with clear implications for the production and maintenance of biodiversity in marine ecosystems. C1 Univ Florida, Dept Fisheries & Aquat Sci, Gainesville, FL 32653 USA. Int Ctr Living Aquat Resources Management, George Town 10670, Malaysia. Smithsonian Trop Res Inst, Balboa, Panama. RP Univ Florida, Dept Fisheries & Aquat Sci, 7922 NW 71St St, Gainesville, FL 32653 USA. EM bowen@gnv.ifas.ufl.edu; ross.robertson@stri.org RI Rocha, Luiz/C-5107-2011 NR 102 TC 189 Z9 219 U1 2 U2 39 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0014-3820 EI 1558-5646 J9 EVOLUTION JI Evolution PD MAY PY 2001 VL 55 IS 5 BP 1029 EP 1039 DI 10.1554/0014-3820(2001)055[1029:POTTAR]2.0.CO;2 PG 11 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 444MK UT WOS:000169403100018 ER PT J AU Eberhard, WG AF Eberhard, WG TI Multiple origins of a major novelty: moveable abdominal lobes in male sepsid flies (Diptera : epsidae), and the question of developmental constraints SO EVOLUTION & DEVELOPMENT LA English DT Article ID DRYOMYZA-ANILIS; EVOLUTION; COMPETITION; BEHAVIOR; ORGANS; FLY AB Contrary to the impression given by their extreme scarcity among extant species of flies, moveable processes on the abdomen are apparently of relatively simple developmental origin, and they have evolved multiple times in males of the small family Sepsidae. They are used to stimulate the female during copulation in two groups, where they are probably independently derived. Because female cuing of reproductive decisions on particular types of stimuli will tend to favor male abilities to elaborate such stimuli, sexual selection by female choice may sometimes result in sustained selection for certain types of innovations in males. The lack of moveable appendages in most dipterans may be due not to developmental constraints, but to lack of selective advantages. C1 Univ Costa Rica, Smithsonian Trop Res Inst, San Jose, Costa Rica. Univ Costa Rica, Escuela Biol, San Jose, Costa Rica. RP Eberhard, WG (reprint author), Univ Costa Rica, Smithsonian Trop Res Inst, Ciudad Univ, San Jose, Costa Rica. NR 70 TC 42 Z9 44 U1 0 U2 7 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 1520-541X J9 EVOL DEV JI Evol. Dev. PD MAY-JUN PY 2001 VL 3 IS 3 BP 206 EP 222 DI 10.1046/j.1525-142x.2001.003003206.x PG 17 WC Evolutionary Biology; Developmental Biology; Genetics & Heredity SC Evolutionary Biology; Developmental Biology; Genetics & Heredity GA 443QQ UT WOS:000169352200008 PM 11440252 ER PT J AU Moss, AM Clutton-Brock, TH Monfort, SL AF Moss, AM Clutton-Brock, TH Monfort, SL TI Longitudinal gonadal steroid excretion in free-living male and female meerkats (Suricata suricatta) SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article DE fecal steroids; urinary steroids; progestagens; estrogens; testosterone; suricates; meerkats ID PAPIO-CYNOCEPHALUS-CYNOCEPHALUS; MONITORING OVARIAN-FUNCTION; DWARF MONGOOSES; REPRODUCTIVE SUPPRESSION; AGGRESSIVE-BEHAVIOR; HOUSE MICE; PREGNANCY; METABOLISM; PUBERTY; FECES AB Slender-tailed meerkats (Suricata suricatta) are small, diurnal, cooperatively breeding mongooses of the family Herpestidae. A prerequisite to fully understanding the mating system of meerkats is the development of a normative reproductive-endocrine database. This study examined longitudinal gonadal steroid excretion in all adult and juvenile individuals of both sexes within a social group of free-living meerkats sampled across an entire breeding season. The specific objectives of this study were to (1) validate noninvasive (fecal and urinary) gonadal steroid hormone monitoring techniques in male (testosterone) and female (estrogens, progestagens) meerkats; (2) test the feasibility of using these noninvasive methods under field conditions; (3) characterize the endocrine correlates associated with the female reproductive cycle, including estrus, gestation, and postpartum estrus; (4) examine longitudinal androgen excretion in males; and (5) determine whether social status (i.e., dominant versus subordinate) affected gonadal steroid excretion. In females, the results demonstrated the physiological validity of noninvasive monitoring in meerkats by corresponding excretory hormone concentrations to major reproductive events (i.e., estrous, pregnancy, parturition). Hormone excretory patterns during estrous intervals suggested possible mechanisms whereby reproductive suppression may operate in female meerkats. In males, androgen excretion did not correspond to changes in reproductive and aggressive behaviors, suggesting that dominance, and hence breeding access to females, was not regulated strictly by gonadal steroid production. The consistency in androgen excretion among male meerkats indicated that reproductive suppression may be mediated by behavioral(i.e., intermale aggression) rather than physiological (i.e., depressed spermatogenesis) mechanisms. (C) 2001 Academic Press. C1 Smithsonian Inst, Natl Zool Pk, Conservat & Res Ctr, Front Royal, VA 22630 USA. George Mason Univ, Dept Biol, Fairfax, VA 22030 USA. Univ Cambridge, Dept Zool, Large Anim Res Grp, Cambridge, England. RP Moss, AM (reprint author), Smithsonian Inst, Natl Zool Pk, Conservat & Res Ctr, 1500 Remount Rd, Front Royal, VA 22630 USA. NR 42 TC 18 Z9 20 U1 2 U2 11 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD MAY PY 2001 VL 122 IS 2 BP 158 EP 171 DI 10.1006/gcen.2001.7622 PG 14 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 428MW UT WOS:000168466300005 PM 11316421 ER PT J AU Dilustro, JJ Day, FP Drake, BG AF Dilustro, JJ Day, FP Drake, BG TI Effects of elevated atmospheric CO2 on root decomposition in a scrub oak ecosystem SO GLOBAL CHANGE BIOLOGY LA English DT Article DE CO2; decomposition; litterbags; nitrogen; roots; scrub oak ID CARBON-DIOXIDE; LITTER DECOMPOSITION; NITROGEN DYNAMICS; PLANT-RESPONSES; LOBLOLLY-PINE; FINE ROOTS; QUALITY; AVAILABILITY; FLORIDA; RHIZOSPHERE AB The effects of elevated atmospheric CO2 on fine root decomposition over a 828-day period were investigated using open top chambers with both ambient and elevated (700 ppm) CO2 treatments in an oak-palmetto scrub ecosystem at Kennedy Space Center, Florida. Carbon dioxide enrichment of the chambers began 15 May 1996. The experiment included roots grown in ambient and elevated carbon dioxide. Vertical litterbags installed in September 1996 in each elevated and ambient chamber incubated from December 1996 to December 1998 showed no significant treatment effect on fine root or rhizome mass loss. Initial fine root percentage mass loss varied from 10.3% to 13.5% after three months; 55.5% to 38.3% of original mass had been lost after 828 days. A period of nitrogen immobilization occurred in both fine roots and rhizomes' in the elevated CO2 incubation, which is a potential mechanism for nitrogen conservation for this system in an elevated CO2 world. C1 Old Dominion Univ, Dept Biol Sci, Norfolk, VA 23529 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Day, FP (reprint author), Old Dominion Univ, Dept Biol Sci, Norfolk, VA 23529 USA. NR 49 TC 21 Z9 23 U1 0 U2 11 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD MAY PY 2001 VL 7 IS 5 BP 581 EP 589 DI 10.1046/j.1354-1013.2001.00428.x PG 9 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 465AC UT WOS:000170564700007 ER PT J AU Warkentin, KM Wassersug, RJ AF Warkentin, KM Wassersug, RJ TI Do prostaglandins regulate external gill regression in anurans? SO JOURNAL OF EXPERIMENTAL ZOOLOGY LA English DT Article ID AXOLOTL AMBYSTOMA-MEXICANUM; AGALYCHNIS-CALLIDRYAS; HATCHING AGE; EMBRYOS; GENE; FROG AB Although the endocrinological mechanism controlling regression of the internal, larval gills of anurans (frogs and toads) is well understood, the mechanism regulating loss of the external, embryonic gills is not known. Based on the homology of the mammalian ductus arteriosus with a portion of the amphibian branchial arches, and the regulation of blood flow in the mammalian ductus by prostaglandins of the E family (PGEs), we hypothesized that anuran external gill loss is also regulated by PGEs. To test this hypothesis, we topically applied both PGE2 and a synthetic analogue of PGE1, misoprostol, to embryos and young hatchlings of the red-eyed treefrog, Agalychnis callidryas. Both agents accelerated external gill regression. Furthermore, misoprostol overrode the inhibitory effect of hypoxia on gill regression in hatchlings and induced rapid loss of external gills in embryos, which normally maintain the gills until hatching. These observations support the hypothesis that PGEs regulate anuran external gill loss. The specific site of action for prostaglandins within the gills is not known; however, PGEs are secreted in the oral mucus of tadpoles, and this could be a natural topical source for these agents. PGEs offer a tool for manipulation of external gills and should facilitate tests of the physiological importance of these structures. J. Exp. Zool. 289:366-373, 2001. (C) 2001 Wiley-Liss, Inc. C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Texas, Dept Zool, Austin, TX 78712 USA. Dalhousie Univ, Dept Anat & Neurobiol, Halifax, NS B3H 4H7, Canada. RP Warkentin, KM (reprint author), Univ Kentucky, Sch Biol Sci, Lexington, KY 40506 USA. NR 25 TC 3 Z9 3 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0022-104X J9 J EXP ZOOL JI J. Exp. Zool. PD MAY 1 PY 2001 VL 289 IS 6 BP 366 EP 373 DI 10.1002/jez.1018 PG 8 WC Zoology SC Zoology GA 428KU UT WOS:000168461500004 PM 11351324 ER PT J AU Chance, KV Ramsay, DA Fink, EH AF Chance, KV Ramsay, DA Fink, EH TI Improved molecular constants for the ground state of DO2 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID HO2; SPECTRUM C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Res Council Canada, Steacie Inst Mol Sci, Ottawa, ON K1A 0R6, Canada. Berg Univ Gesamthsch Wuppertal, Fachbereich Phys Chem 9, D-42097 Wuppertal, Germany. RP Chance, KV (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Chance, Kelly/0000-0002-7339-7577 NR 5 TC 3 Z9 3 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 2001 VL 207 IS 1 BP 123 EP 123 DI 10.1006/jmsp.2001.8310 PG 1 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 435ZY UT WOS:000168913100020 ER PT J AU Pandolfi, JM AF Pandolfi, JM TI Numerical and taxonomic scale of analysis in paleoecological data sets: Examples from neo-tropical Pleistocene reef coral communities SO JOURNAL OF PALEONTOLOGY LA English DT Article ID MACROINVERTEBRATE COMMUNITIES; RESOLUTION; POLLUTION; PATTERNS; IMPACT; QUANTIFICATION; MACROBENTHOS; ASSEMBLAGES; SUFFICIENT; ECOLOGY AB I investigated the degree to which the interpretation of reef coral distribution data is influenced by the numerical and taxonomic scale of analysis in Pleistocene coral communities from the Caribbean Sea. Patterns of community differentiation analyzed at both species and genus levels showed only small differences using different numerical scales (relative abundance, rank abundance and species presence and absence). Whereas some differences were observed between species and genus level patterns, they had little effect on paleoecological interpretations. The greatest differences occurred when presence and absence analyses of assemblages sampled along 40-m transects were compared with those sampled along 40-m transects augmented by a one-hour search for rare taxa. These results suggest that paleoecological interpretations of Quaternary coral communities are robust to numerical scale of analysis at the species and genus level, and to taxonomic scale between the species and genus level. However, interpretations of community structure are sensitive to sampling intensity, geographic scale, and sample size. C1 Smithsonian Inst, Museum Natl Hist Nat, Dept Paleobiol, Washington, DC 20560 USA. RP Pandolfi, JM (reprint author), Smithsonian Inst, Museum Natl Hist Nat, Dept Paleobiol, MRC-121, Washington, DC 20560 USA. RI Pandolfi, John/A-3121-2009 OI Pandolfi, John/0000-0003-3047-6694 NR 44 TC 17 Z9 18 U1 0 U2 5 PU PALEONTOLOGICAL SOC INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0022-3360 J9 J PALEONTOL JI J. Paleontol. PD MAY PY 2001 VL 75 IS 3 BP 546 EP 563 DI 10.1666/0022-3360(2001)075<0546:NATSOA>2.0.CO;2 PG 18 WC Paleontology SC Paleontology GA 438UD UT WOS:000169071900005 ER PT J AU Cheetham, AH Jackson, JBC Sanner, J AF Cheetham, AH Jackson, JBC Sanner, J TI Evolutionary significance of sexual and asexual modes of propagation in neogene species of the bryozoan metrarabdotos in tropical America SO JOURNAL OF PALEONTOLOGY LA English DT Article ID QUANTITATIVE GENETICS; CHEILOSTOME BRYOZOANS; PHENOTYPIC EVOLUTION; TEMPO; MORPHOLOGY; SELECTION; ANIMALS; GROWTH AB Three new Miocene-Pliocene species of the cheilostome bryozoan Metrarabdotos from Venezuela are atypical in showing significant evidence that as many as half the colonies originated asexually (clonally) by "regeneration" from previously existing colonies, rather than almost exclusively from ancestrular zooids (products of metamorphosis of sexually produced larvae), as is characteristic of the genus. The extremely low proportion of zooids (less than two percent) recognizably committed to producing larvae (ovicelled) in these Venezuelan species agrees with that reported in a variety of Danian (Paleocene) genera in which clonal propagation has been reported to predominate. However, all but two of 17 other living and fossil species of Metrarabdotos also have fewer than two percent of their zooids ovicelled, even though all but one of more than 250 colony bases examined originated from ancestrulae. The lack of significant correlation in Metrarabdotos between frequencies of ovicelled zooids and of ancestrular colonies suggests that clonal propagation may not have diverted resources from sexual reproduction. This inference is supported by the retention in these species of a level of heritable morphologic variation (estimated by partitioning among-colonies and within-colonies variance in zooid characters) that is commensurate with that estimated for species of Metrarabdotos in which propagation was apparently entirely by sexual means. Thus, sexual reproduction throughout the genus was apparently sufficient to maintain the genetic diversity from which speciation could proceed at normal rates. As estimated by both cladistic and nearest-neighbor morphologic-stratigraphic methods, the three Venezuelan species occupy quite different positions in the inferred phylogeny of Metrarabdotos. Thus, the elevated level of clonal propagation in these species appears to be a response to local conditions, most probably high productivity associated with upwelling, that promoted more rapid vegetative growth while leaving the level of sexual reproduction unchanged. C1 Smithsonian Inst, Museum Natl Hist Nat, Dept Paleobiol, Washington, DC USA. Scripps Inst Oceanog, Geosci Res Div, La Jolla, CA 92093 USA. RP Cheetham, AH (reprint author), Smithsonian Inst, Museum Natl Hist Nat, Dept Paleobiol, Washington, DC USA. NR 35 TC 14 Z9 17 U1 1 U2 3 PU PALEONTOLOGICAL SOC INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0022-3360 J9 J PALEONTOL JI J. Paleontol. PD MAY PY 2001 VL 75 IS 3 BP 564 EP 577 DI 10.1666/0022-3360(2001)075<0564:ESOSAA>2.0.CO;2 PG 14 WC Paleontology SC Paleontology GA 438UD UT WOS:000169071900006 ER PT J AU Marko, PB Jackson, JBC AF Marko, PB Jackson, JBC TI Patterns of morphological diversity among and within arcid bivalve species pairs separated by the Isthmus of Panama SO JOURNAL OF PALEONTOLOGY LA English DT Article ID TROPICAL AMERICAN MOLLUSKS; NORTHEASTERN PACIFIC; MITOCHONDRIAL-DNA; 2 SIDES; SPECIATION; SEA; EXTINCTION; DIVERGENCE; EVOLUTION; ELECTROPHORESIS AB Geminate species are morphologically similar sister-species found on either side of the Isthmus of Panama. The existence of all geminates in the tropical Eastern Pacific ocean and the Caribbean Sea is most often explained by vicariance: closure of the Central American Seaway 3.1 to 3.5 Ma simultaneously isolated populations of species with amphi-American distributions. In this paper, we test the potential of morphological measurements for discriminating between Recent geminate species pairs from three genera (Arca, Arcopsis, and Barbatia) in the bivalve family Arcidae and examine the prospects for distinguishing nominal species in the fossil record. Fourteen morphological variables were used to characterize shell shape and multivariate methods were used to discriminate between five Recent species pairs. Collection sites were also used as a priori groups for discrimination to describe patterns of intraspecific morphological variation and to evaluate differences among samples from different geographic regions. On average, 84 percent of specimens within geminate pairs are classified correctly following five separate discriminant analyses with nominal species as the grouping variable. Although all but one arcid species pair are discriminated with high statistical significance, some collection sites within species are highly morphologically distinct. Overall, a large proportion of specimens from each collection locality (79 percent on average) can be classified correctly to site although no single site possessed a multivariate centroid that was significantly different from all other conspecific centroids. The distinctiveness of some collection sites, however, raises the possibility that some nominal species may harbor cryptic species, indicating the need for wider geographic surveys of both molecular and morphological variation within geminate species pairs. The eigenvalue coefficients derived from the Recent samples of one geminate pair (Arca mutabilis and A. imbricata) were used to assess the potential for identifying arcid species in the fossil record. Discriminant analyses of fossil Area indicate that the forms that characterize Recent A. mutabilis and A. imbricata are present in the fossil record as far back as the Late Early Miocene, in the Cantaure Formation of Venezuela. Because a deep water connection between the Eastern Pacific and Western Atlantic existed until the Middle Miocene, the morphological differences associated with Recent A. mutabilis and A. imbricata likely existed well before the rising Isthmus affected ocean circulation patterns in tropical America. Therefore, despite great overall morphological similarity, these putative geminate species likely have a time of divergence that is at least four times older than final seaway closure. The geographic distribution of fossils also suggests that morphological forms associated with each Recent species had amphi-American distributions both before and after isthmus formation but are now geographically restricted to either side of the isthmus in the Recent fauna. C1 Univ Calif San Diego, Scripps Inst Oceanog, Geosci Res Div, La Jolla, CA 92093 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Marko, PB (reprint author), Nat Hist Museum Los Angeles Cty, 900 Exposit Blvd, Los Angeles, CA 90007 USA. NR 82 TC 33 Z9 33 U1 0 U2 7 PU PALEONTOLOGICAL SOC INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0022-3360 J9 J PALEONTOL JI J. Paleontol. PD MAY PY 2001 VL 75 IS 3 BP 590 EP 606 DI 10.1666/0022-3360(2001)075<0590:POMDAA>2.0.CO;2 PG 17 WC Paleontology SC Paleontology GA 438UD UT WOS:000169071900008 ER PT J AU Banaszak, AT Neale, PJ AF Banaszak, AT Neale, PJ TI Ultraviolet radiation sensitivity of photosynthesis in phytoplankton from an estuarine environment SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID UV-ABSORBING COMPOUNDS; B RADIATION; ANTARCTIC PHYTOPLANKTON; MARINE-PHYTOPLANKTON; OZONE DEPLETION; ANACYSTIS-NIDULANS; AMINO-ACIDS; PHOTOINHIBITION; INHIBITION; LIGHT AB We have studied temporal variation in the sensitivity of phytoplankton photosynthesis to inhibition by ultraviolet radiation (UV; 280-400 nm) using biological weighting functions (BWFs) that quantify the biological effect of different wavelengths of UV. Variations in irradiance-dependent BWFs were evaluated for natural phytoplankton assemblages from the Rhode River, a shallow subestuary of the Chesapeake Bay, Maryland, from October 1994 to July 1996. Phytoplankton assemblages were sensitive to UV throughout the year. Rhode River assemblages are inhibited more strongly in the UV-B (280-320 nm), particularly below 300 nm, but there is a significant influence well into the W-A (320-400 nm). There was no inhibition of phytoplankton photosynthesis by photosynthetically available radiation (400-700 nm), but there was significant seasonal variation in the saturated rate of photosynthesis (P-s(B)) and in the light saturation parameter (E-s). There was little variation in seasonal average BWFs through the year, but then was considerable variation in BWFs during each season. Individual BWFs varied both in absolute values of the weightings (reciprocal [mW m(-2)]) and in the spectral shape or relative effect of UV-B versus UV-A, which may be due to changes in species composition, light, temperature, and nutrient availability. Comparison of the most sensitive assemblage (spring) with the least sensitive assemblage (winter) indicates that these BWFs are close to the upper and lower bounds in sensitivity for irradiance-dependent BWFs from all natural and cultured phytoplankton populations. The average, absolute spectral weightings for inhibition of photosynthesis in assemblages from the Rhode River an similar to an average BWF for Antarctic assemblages. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Neale, PJ (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. RI Neale, Patrick/A-3683-2012 NR 49 TC 36 Z9 37 U1 0 U2 0 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAY PY 2001 VL 46 IS 3 BP 592 EP 603 PG 12 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 429HV UT WOS:000168511500012 ER PT J AU Komatsu, M Krot, AN Petaev, MI Ulyanov, AA Keil, K Miyamoto, M AF Komatsu, M Krot, AN Petaev, MI Ulyanov, AA Keil, K Miyamoto, M TI Mineralogy and petrography of amoeboid olivine aggregates from the reduced CV3 chondrites Efremovka, Leoville and Vigarano: Products of nebular condensation, accretion and annealing SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID ALUMINUM-RICH INCLUSIONS; CARBONACEOUS CHONDRITES; REFRACTORY INCLUSIONS; CHEMICAL-COMPOSITIONS; SOLAR NEBULA; CHONDRULES; ORIGIN; METEORITE; ALLENDE; CONSTRAINTS AB Amoeboid olivine aggregates (AOAs) from the reduced CV chondrites Efremovka, Leoville and Vigarano are irregularly-shaped objects, up to 5 mm in size, composed of forsteritic olivine (Fa(lo) and a refractory, Ca,Al-rich component. The AOAs are depleted in moderately volatile elements (Mn, Cr, Na, K), Fe,Ni-metal and sulfides and contain no low-Ca pyroxene. The refractory component consists of fine-grained calcium-aluminum-rich inclusions (CAIs) composed of Al-diopside, anorthite (An(100)), and magnesium-rich spinel (similar to1 wt% FeO) or fine-grained intergrowths of these minerals; secondary nepheline and sodalite are very minor. This indicates that AOAs from the reduced CV chondrites are more pristine than those from the oxidized CV chondrites Allende and Mokoia. Although AOAs from the reduced CV chondrites show evidence for high-temperature nebular annealing (e.g., forsterite grain boundaries form 120 degrees triple junctions) and possibly a minor degree of melting of Al-diopside-anorthite materials, none of the AOAs studied appear to have experienced extensive (> 50%) melting. We infer that AOAs are aggregates of high-temperature nebular condensates, which formed in CAI-forming regions, and that they were absent from chondrule-forming regions at the time of chondrule formation. The absence of low-Ca pyroxene and depletion in moderately volatile elements (Mn, Cr, Na, K) suggest that AOAs were either removed from CAI-forming regions prior to condensation of these elements and low-Ca pyroxene or gas-solid condensation of low-Ca-pyroxene was kinetically inhibited. C1 Univ Hawaii Manoa, Hawaii Inst Geophys & Planetol, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. Univ Tokyo, Dept Earth & Planetary Sci, Bunkyo Ku, Tokyo 1130033, Japan. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Moscow MV Lomonosov State Univ, Moscow 117999, Russia. RP Krot, AN (reprint author), Univ Hawaii Manoa, Hawaii Inst Geophys & Planetol, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. NR 51 TC 57 Z9 58 U1 1 U2 3 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD MAY PY 2001 VL 36 IS 5 BP 629 EP 641 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 438YF UT WOS:000169081300006 ER PT J AU Weil, SE AF Weil, SE TI Exhibitionism: Art in an era of intolerance SO MUSEUM NEWS LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Weil, SE (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC MUSEUMS PI WASHINGTON PA 1575 EYE ST, NW, STE 400, WASHINGTON, DC 20005 USA SN 0027-4089 J9 MUSEUM NEWS JI Mus. News PD MAY-JUN PY 2001 VL 80 IS 3 BP 37 EP + PG 0 WC Art SC Art GA 428CU UT WOS:000168444200016 ER PT J AU Cecchi-Pestellini, C Barletti, L AF Cecchi-Pestellini, C Barletti, L TI Radiative transfer in a stochastic universe - I. Observation-related statistics SO NEW ASTRONOMY LA English DT Article DE intergalactic medium; radiative transfer AB The radiative transfer through an astronomical region populated by stochastic clumps is studied by means of functional analytical techniques. Random density fluctuations of the background medium are described by a finite number of parameters. In the framework, each realization of the statistics corresponds to a possible configuration of a real clumpy region, as it is possible to infer from observations. (C) 2001 Published by Elsevier Science B.V. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. Univ Florence, Dipartimento Matemat U Dini, I-50134 Florence, Italy. RP Cecchi-Pestellini, C (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Cecchi Pestellini, Cesare/0000-0001-7480-0324 NR 8 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1384-1092 J9 NEW ASTRON JI New Astron. PD MAY PY 2001 VL 6 IS 3 BP 151 EP 162 DI 10.1016/S1384-1076(01)00046-X PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 437GN UT WOS:000168983600002 ER PT J AU Barletti, L Cecchi-Pestellini, C AF Barletti, L Cecchi-Pestellini, C TI Radiative transfer in a stochastic universe - II. The method of projections SO NEW ASTRONOMY LA English DT Article DE intergalactic medium; radiative transfer AB The radiative transfer through a region with stochastic clumps is studied into an abstract Banach space setting. The distribution of clumps is described by means of an observation-related statistics. By using a projection technique, sequences of evolution equations, which approximate the exact equation for the expectation, are deduced. (C) 2001 Published by Elsevier Science B.V. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Florence, Dipartimento Matemat U Dini, I-50134 Florence, Italy. Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. RP Cecchi-Pestellini, C (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Cecchi Pestellini, Cesare/0000-0001-7480-0324 NR 9 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1384-1092 J9 NEW ASTRON JI New Astron. PD MAY PY 2001 VL 6 IS 3 BP 165 EP 172 DI 10.1016/S1384-1076(01)00045-8 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 437GN UT WOS:000168983600003 ER PT J AU Apple, JL Feener, DH AF Apple, JL Feener, DH TI Ant visitation of extrafloral nectaries of Passiflora: the effects of nectary attributes and ant behavior on patterns in facultative ant-plant mutualisms SO OECOLOGIA LA English DT Article DE ants; extrafloral nectaries; facultative interactions; Passiflora; mutualism ID NEOTROPICAL HERB; AMINO-ACIDS; HERBIVORE; PROTECTION; MEXICO; MIMOSOIDEAE; FOREST AB Extrafloral nectary (EFN) plants are widespread and can be quite species-rich in some communities. Thus, ants that utilize extrafloral nectar may have the opportunity to discriminate among a wide variety of nectar sources, resulting in variation in the ant attention EFN plants receive. In this study, we compare ant visitation rates of three Passiflora species that coexist in an early successional neotropical forest. These three vine species (Passiflora auriculata, P. biflora, and P. oerstedii) differ in their extrafloral nectary structure and placement, and thus may attract different numbers or species of ants. Through censuses of ants tending extrafloral nectaries, we found that P. auriculata received significantly higher numbers of ant visitors than P. oerstedii, but did not differ significantly from P. biflora in its attractiveness to ants. We also found that termite worker baits (simulating herbivores) placed on P. auriculata and P. biflora were discovered by ants significantly more quickly than baits placed on P. oerstedii. In both ant visitation censuses and in termite bait trials, we found no significant associations between Passiflora species and the species of ant visitors. We also performed experimental manipulations of several characteristics of P. auriculata, which resulted in changes in levels of ant visitation. When petiolar nectaries of P. auriculata were experimentally blocked, visitation by the common ant Ec tatomma ruidum declined, even though nectaries on the leaf surfaces were still functional. Connections with other vegetation also had an effect on ant visitation. Though experimental creation of connections between growing P. auriculata shoots and other vegetation did not enhance ant visitation, eliminating connections resulted in a significant decline in the number of ant visitors. The results of this study suggest factors that may contribute to variation in ant visitation of extrafloral nectary plants. In addition, this study demonstrates that extrafloral nectary plants co-occurring in a habitat and available to the same ants may differ in patterns of visitation by ants and perhaps in the duality of protection from herbivores that they receive. C1 Univ Utah, Dept Biol, Salt Lake City, UT 84112 USA. RP Apple, JL (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. NR 39 TC 50 Z9 53 U1 0 U2 15 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0029-8549 J9 OECOLOGIA JI Oecologia PD MAY PY 2001 VL 127 IS 3 BP 409 EP 416 PG 8 WC Ecology SC Environmental Sciences & Ecology GA 434ED UT WOS:000168801400013 ER PT J AU Zygelman, B Saenz, A Froelich, P Jonsell, S Dalgarno, A AF Zygelman, B Saenz, A Froelich, P Jonsell, S Dalgarno, A TI Radiative association of atomic hydrogen with antihydrogen at subkelvin temperatures SO PHYSICAL REVIEW A LA English DT Article ID ANNIHILATION; ANTIPROTON AB Partial and total cross sections for the radiative association process H+(H) over bar-->H (H) over bar +h nu in the sub-Kelvin temperature regime are reported. We calculate the emission spectra for this process and suggest its utility as a diagnostic. The cross section for radiative association is found to have the value sigma =6.85x10(-22) cm(2)/rootT, where T is an effective temperature. It is significantly smaller than the in-flight annihilation and fragmentation cross sections. We discuss the role that radiative association plays in the formation of a quasibound system of the H (H) over bar molecule. C1 Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Univ Uppsala, Dept Quantum Chem, S-75120 Uppsala, Sweden. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Zygelman, B (reprint author), Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. RI Jonsell, Svante/J-2251-2016 OI Jonsell, Svante/0000-0003-4969-1714 NR 16 TC 24 Z9 24 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2001 VL 63 IS 5 BP art. no. EP 052722 DI 10.1103/PhysRevA.63.052722 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 430RJ UT WOS:000168589100079 ER PT J AU Derevianko, A Babb, JF Dalgarno, A AF Derevianko, A Babb, JF Dalgarno, A TI High-precision calculations of van der Waals coefficients for heteronuclear alkali-metal dimers SO PHYSICAL REVIEW A LA English DT Article ID LONG-RANGE POTENTIALS; MAGNETOOPTICAL TRAP; DISPERSION COEFFICIENTS; MATRIX-ELEMENTS; COLD COLLISIONS; ATOMS; STATE; POLARIZABILITIES; SCATTERING; NAK AB van der Waals coefficients for the heteronuclear alkali-metal dimers of Li, Na, K, Rb, Cs, and Fr are calculated using relativistic nb initio methods augmented by high-precision experimental data. We argue that the uncertainties in the coefficients are unlikely to exceed about 1%. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Univ Nevada, Dept Phys, Reno, NV 89557 USA. RP Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RI Derevianko, Andrei/G-8356-2011 NR 38 TC 104 Z9 104 U1 1 U2 15 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2001 VL 63 IS 5 AR 052704 DI 10.1103/PhysRevA.63.052704 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 430RJ UT WOS:000168589100061 ER PT J AU Blackman, EG Field, GB AF Blackman, EG Field, GB TI How astrophysical mean field dynamos can circumvent existing quenching constraints SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 42nd Annual Meeting of the Division of Plasma Physics Of the American-Physical-Society/10th International Congress on Plasma Physics CY OCT 23-27, 2000 CL QUEBEC CITY, CANADA SP Amer Phys Soc, Div Plasma Phys ID MAGNETIC HELICITY; TURBULENT DYNAMOS; NONLINEAR DYNAMO; ACCRETION DISKS; ELECTRODYNAMICS; ROTATION; ALPHA; CORONA; MODEL AB Mean field dynamo theory is a leading candidate to explain the large scale magnetic fields of galaxies and stars. However, controversy arises over the extent of quenching by the backreaction of the growing field. Here boundary conditions and magnetic helicity flow are shown to play a role in determining whether the mean field dynamo action is fast, as required by astrophysical systems, or resistively limited (slow). Existing work suggesting that mean field dynamos are resistively limited include restrictive approximations such as stationarity and periodic boundary conditions that suppress magnetic helicity flow. Thus even though the backreaction is present, such studies cannot unambiguously reveal whether real astrophysical mean field dynamos are dynamically suppressed when the helicity flow is allowed. If the dynamo is sustained by an outflow of helicity from the system, then a magnetically active corona is expected. Open boundaries alone may not be sufficient for rapid dynamo action and the additional physics of buoyancy and outflows may be required. Possible simulation approaches to test some of the principles are briefly discussed. Some limitations of the "Zeldovich relation" are also addressed. (C) 2001 American Institute of Physics. C1 Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. Harvard Smithsonian Ctr Astrophys, CFA, Cambridge, MA 02139 USA. RP Blackman, EG (reprint author), Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. NR 60 TC 14 Z9 14 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 2001 VL 8 IS 5 BP 2407 EP 2414 DI 10.1063/1.1351830 PN 2 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 423QP UT WOS:000168188500081 ER PT J AU Owsley, DW Hunt, DR AF Owsley, DW Hunt, DR TI Clovis and early archaic crania from the Anzick site (24PA506), Park County, Montana SO PLAINS ANTHROPOLOGIST LA English DT Article DE Anzick site; Clovis burial; archaeology; osteology; taphonomy; red ocher AB The Anzick archaeological sire in Montana, known since 1968, has been recognized since 1974 as Clovis age because of the lithic material recovered. Now it is possible to assert that some. but not all, of the recovered skeletal material is also Clovis age. The site contained more than 100 stone and non-human bone artifacts in association with the partial skeletal remains of a young child. All were covered with red ocher. The partial cranium of a second youth, not stained red, was also recovered. Recently, radiocarbon dating of these two crania produced two separate ages, 2000 years apart. Forensic examination of the remains, completed in 1999, has determined their ages at death. This site, an important addition to New World prehistory contains not only the largest single assemblage of Clovis artifacts but also the only known Clovis skeletal remains. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Anthropol, Washington, DC 20560 USA. RP Owsley, DW (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Anthropol, Washington, DC 20560 USA. NR 15 TC 19 Z9 19 U1 2 U2 5 PU PLAINS ANTHROPOLOGICAL SOC PI LINCOLN PA 410 WEDGEWOOD DRIVE, LINCOLN, NE 68510 USA SN 0032-0447 J9 PLAINS ANTHROPOL JI Plains Anthropol. PD MAY PY 2001 VL 46 IS 176 BP 115 EP 124 PG 10 WC Anthropology SC Anthropology GA 439WA UT WOS:000169139500001 ER PT J AU Stark, AA Bally, J Balm, SP Bania, TM Bolatto, AD Chamberlin, RA Engargiola, G Huang, M Ingalls, JG Jacobs, K Jackson, JM Kooi, JW Lane, AP Lo, KY Marks, RD Martin, CL Mumma, D Ojha, R Schieder, R Staguhn, J Stutzki, J Walker, CK Wilson, RW Wright, GA Zhang, XL Zimmermann, P Zimmermann, R AF Stark, AA Bally, J Balm, SP Bania, TM Bolatto, AD Chamberlin, RA Engargiola, G Huang, M Ingalls, JG Jacobs, K Jackson, JM Kooi, JW Lane, AP Lo, KY Marks, RD Martin, CL Mumma, D Ojha, R Schieder, R Staguhn, J Stutzki, J Walker, CK Wilson, RW Wright, GA Zhang, XL Zimmermann, P Zimmermann, R TI The Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID 225-GHZ ATMOSPHERIC OPACITY; SOUTH-POLE; MICROWAVE SKY; ANGULAR SCALES; 90 GHZ; ANISOTROPY; RECEIVER; MIXERS; INTERFEROMETER; CALIBRATION AB The Antarctic Submillimeter Telescope and Remote Observatory, a 1.7 m diameter telescope for astronomy and aeronomy studies at wavelengths between 200 and 2000 mum, was installed at the South Pole during the 1994-1995 austral summer. The telescope operates continuously through the austral winter and is being used primarily for spectroscopic studies of neutral atomic carbon and carbon monoxide in the interstellar medium of the Milky Way and the Magellanic Clouds. The South Pole environment is unique among observatory sites for unusually low wind speeds, low absolute humidity, and the consistent clarity of the submillimeter sky. Especially significant are the exceptionally low values of sky noise found at this site, a result of the small water vapor content of the atmosphere. Four heterodyne receivers, an array receiver, three acousto-optical spectrometers, and an array spectrometer are currently installed. A Fabry-Perot spectrometer using a bolometric array and a terahertz receiver are in development. Telescope pointing, focus, and calibration methods as well as the unique working environment and logistical requirements of the South Pole are described. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Bell Labs, Holmdel, NJ 07733 USA. Univ Colorado, CASA, Boulder, CO 80309 USA. Boston Univ, Boston, MA 02215 USA. CALTECH Submillimeter Observ, Hilo, HI 96720 USA. Univ Illinois, Urbana, IL 61801 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. CALTECH, Pasadena, CA 91125 USA. Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Radiometer Phys GmbH, D-53340 Meckenheim, Germany. RP Stark, AA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM aas@cfa.harvard.edu; greg@astron.berkeley.edu; adair@cfa.harvard.edu; cmartin@cfa.harvard.edu; staguhn@stars.gsfc.nasa.gov; zhang@stars.gsfc.nasa.gov RI Bania, Thomas/H-2318-2014; OI Wilson, Robert/0000-0001-5694-6725 NR 51 TC 61 Z9 61 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAY PY 2001 VL 113 IS 783 BP 567 EP 585 DI 10.1086/320281 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 427QF UT WOS:000168416400007 ER PT J AU Monnier, JD AF Monnier, JD TI Asymmetric beam combination for optical interferometry SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID STELLAR INTERFEROMETER; INTERFEROGRAMS; SUPERGIANTS AB Optical interferometers increasingly use single-mode fibers as spatial filters to convert varying wave-front distortion into intensity fluctuations which can be monitored for accurate calibration of fringe amplitudes. Here I propose using an asymmetric coupler to allow the photometric intensities of each telescope beam to be measured at the same time as the fringe visibility but without the need for dedicated photometric outputs, which reduce the light throughput in the interferometric channels. In the read-noise-limited case often encountered in the infrared, I show that a 53% improvement in signal-to-noise ratio for the visibility amplitude measurement is achievable, when compared to a balanced coupler setup with 50% photometric taps (e.g., the FLUOR experiment). In the Poisson-noise limit appropriate for visible light, the improvement is reduced to only similar to8%. This scheme also reduces the cost and complexity of the beam combination since fewer components and detectors are required and since it can be extended to more than two telescopes for "all-in-one" or pairwise beam combination. Asymmetric beam combination can also be employed for monitoring scintillation and throughput variations in systems without spatial filtering. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Monnier, JD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 42, Cambridge, MA 02138 USA. NR 11 TC 13 Z9 13 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAY PY 2001 VL 113 IS 783 BP 639 EP 645 DI 10.1086/320288 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 427QF UT WOS:000168416400011 ER PT J AU Ryutova, M Habbal, S Woo, R Tarbell, T AF Ryutova, M Habbal, S Woo, R Tarbell, T TI Photospheric network as the energy source for the quiet-Sun corona SO SOLAR PHYSICS LA English DT Article ID SOLAR-WIND; TRANSITION REGION; SCALE STRUCTURES; ATMOSPHERE; FLOW AB We propose a mechanism for the formation of a magnetic energy avalanche based on highly dynamic phenomena within the ubiquitous small-scale network magnetic elements in the quiet photosphere. We suggest that this mechanism may provide constant mass and energy supply for the corona and fast wind. Constantly emerging from sub-surface layers, flux tubes collide and reconnect generating magneto-hydrodynamic shocks that experience strong gradient acceleration in the sharply stratified photosphere/chromosphere region. Acoustic and fast magnetosonic branches of these waves lead to heating and/or jet formation due to cumulative effects (Tarbell et al., 1999). The Alfven waves generated by post-reconnection processes have quite a restricted range of parameters for shock formation, but their frequency, determined by the reconnection rate, may be high enough (omega similar or equal to 0.1-2.5 s(-1)) to carry the energy into the corona. We also suggest that the primary energy source for the fast wind lies far below the coronal heights, and that the chromosphere and transition region flows and also radiative transient form the base of the fast wind. The continuous supply of emerging magnetic flux tubes provides a permanent energy production process capable of explaining the steady character of the fast wind and its energetics. C1 Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lockheed Martin Solar & Astrophys Lab, Palo Alto, CA 94304 USA. RP Ryutova, M (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. EM ryutova@beowulf.ucllnl.org; habbal@cfassp31.harvard.edu; rwoo@mail1.jpl.nasa.gov; tarbell@lmsal.com NR 28 TC 27 Z9 27 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAY PY 2001 VL 200 IS 1-2 BP 213 EP 234 DI 10.1023/A:1010374005082 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 456DK UT WOS:000170067700016 ER PT J AU de Queiroz, K Poe, S AF de Queiroz, K Poe, S TI Philosophy and phylogenetic inference: A comparison of likelihood and parsimony methods in the context of Karl Popper's writings on corroboration SO SYSTEMATIC BIOLOGY LA English DT Article DE assumptions; corroboration; Karl Popper; likelihood; parsimony; philosophy; phylogeny; probability ID MAXIMUM-LIKELIHOOD; DNA SUBSTITUTION; EVOLUTIONARY TREES; STATISTICAL TESTS; SEQUENCE DATA; SYSTEMATICS; MODELS; COMPATIBILITY; PROBABILITY; HYPOTHESES AB Advocates of cladistic parsimony methods have invoked the philosophy of Karl Popper in an attempt to argue for the superiority of those methods over phylogenetic methods based on Ronald Fisher's statistical principle of likelihood. We argue that the concept of likelihood in general, and its application to problems of phylogenetic inference in particular, are highly compatible with Popper's philosophy. Examination of Popper's writings reveals that his concept of corroboration is, in fact, based on likelihood. Moreover, because probabilistic assumptions are necessary for calculating the probabilities that define Popper's corroboration, likelihood methods of phylogenetic inference- with their explicit probabilistic basis- are easily reconciled with his concept. In contrast, cladistic parsimony methods, at least as described by certain advocates of those methods, are less easily reconciled with Popper's concept of corroboration. If those methods are interpreted as lacking probabilistic assumptions, then they are incompatible with corroboration. Conversely, if parsimony methods are to be considered compatible with corroboration, then they must be interpreted as carrying implicit probabilistic assumptions. Thus, the non-probabilistic interpretation of cladistic parsimony favored by some advocates of those methods is contradicted by an attempt by the same authors to justify parsimony methods in terms of Popper's concept of corroboration. In addition to being compatible with Popperian corroboration, the likelihood approach to phylogenetic inference permits researchers to test the assumptions of their analytical methods (models) in a way that is consistent with Popper's ideas about the provisional nature of background knowledge. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. Univ Texas, Dept Zool, Austin, TX 78712 USA. Univ Texas, Texas Mem Museum, Austin, TX 78712 USA. Univ Calif Berkeley, Museum Vertebrate Zool, Berkeley, CA 94720 USA. RP de Queiroz, K (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. NR 49 TC 46 Z9 48 U1 1 U2 5 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 1063-5157 J9 SYST BIOL JI Syst. Biol. PD MAY-JUN PY 2001 VL 50 IS 3 BP 305 EP 321 DI 10.1080/106351501300317941 PG 17 WC Evolutionary Biology SC Evolutionary Biology GA 451VN UT WOS:000169823200003 PM 12116577 ER PT J AU Soares, MP Riet-Correa, F Smith, DR Soares, MP Mendez, M Brandolt, AL AF Soares, MP Riet-Correa, F Smith, DR Soares, MP Mendez, M Brandolt, AL TI Experimental intoxication by larvae of Perreyia flavipes Konow, 1899 (Hymenoptera : Pergidae) in pigs and some aspects on its biology SO TOXICON LA English DT Article DE Perreyia flavipes Konow; sawfly toxicity; liver necrosis; swine AB Two pigs were dosed with 5 and 10 g/kg bw of fresh Pen Perreyia flavipes larvae collected at the municipality of Pelotas. Two other pigs were dosed with 0.87 and 1.7 g/kg of dry P. flavipes (equivalent to 5 and 10 g/kg bw of fresh larvae). Another pig was dosed with 0.17 g/kg of dry larvae, daily, during 20 d, Forty-eight hours after the ingestion, all pigs that ingested single doses showed clinical signs and marked rise in serum aspartate aminotransferase. Alanine aminotransferase and gamma glutamil-transferase were also slightly increased. The pig dosed with 10 g/kg of fresh larvae died in 96 h, The others recovered in 4-5 days after ingestion. No clinical signs were observed in the pigs dosed during 20 d with 0.17 g/kg of dry larvae. The main lesion observed in the pig dosed whit 10 g/kg of fresh larvae was a centrilobular liver necrosis, These results confirmed the toxicity of P. flavipes for swine, demonstrated that the larvae maintain the toxicity after being dried, and suggest no cumulative effect in the larval toxicity. The larvae collected in the held were conditioned in boxes containing swards of native grasses and covered with gauze to prevent the escape of adults on emergence. The larvae pupated from August 11 to September 25. Emergency of adults: occurred from February 10 to March 4. Adult females and males live only fur 18-36 and 24-48 h, respectively. The eggs had an incubation period of 16-33 d. The larval period extend from March 1 to August 24. (C) 2000 Elsevier Science Ltd, All rights reserved. C1 Ufpel, Fac Vet, Lab Reg Diagnost, BR-96010900 Pelotas, RS, Brazil. Smithsonian Inst, Natl Museum Nat Hist, USDA, Agr Res Serv,PSI,Systmat Entomol Lab, Washington, DC 20560 USA. RP Soares, MP (reprint author), Ufpel, Fac Vet, Lab Reg Diagnost, BR-96010900 Pelotas, RS, Brazil. EM mpsoares@ufpel.tehe.br NR 14 TC 9 Z9 10 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0041-0101 J9 TOXICON JI Toxicon PD MAY PY 2001 VL 39 IS 5 BP 669 EP 678 DI 10.1016/S0041-0101(00)00192-6 PG 10 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA 384AF UT WOS:000165916300009 PM 11072046 ER PT J AU Weldon, PJ Burghardt, GM AF Weldon, PJ Burghardt, GM TI Deception (mimicry): an integral component of sexual signals SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Letter C1 Smithsonian Inst, Conservat & Res Ctr, Front Royal, VA 22630 USA. Univ Tennessee, Dept Psychol, Knoxville, TN 37996 USA. Univ Tennessee, Dept Ecol & Evolutionary Biol, Knoxville, TN 37996 USA. RP Weldon, PJ (reprint author), Smithsonian Inst, Conservat & Res Ctr, 1500 Remount Rd, Front Royal, VA 22630 USA. RI Burghardt, Gordon/E-4501-2010 OI Burghardt, Gordon/0000-0003-4943-8145 NR 10 TC 2 Z9 2 U1 3 U2 11 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD MAY PY 2001 VL 16 IS 5 BP 228 EP 228 DI 10.1016/S0169-5347(01)02134-6 PG 1 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 428GW UT WOS:000168454200008 ER PT J AU Correll, DL Jordan, TE Weller, DE AF Correll, DL Jordan, TE Weller, DE TI Effects of precipitation, air temperature, and land use on organic carbon discharges from rhode river watersheds SO WATER AIR AND SOIL POLLUTION LA English DT Article DE air temperature; dissolved organic carbon; particulate organic carbon; precipitation; watershed; weather effects ID PARTIALLY STRATIFIED ESTUARY; BOREAL FOREST WATERSHEDS; CHESAPEAKE BAY; NUTRIENT DYNAMICS; PHOSPHORUS; EXPORT; NITROGEN; STREAMS; PHYTOPLANKTON; TRANSPORT AB We studied discharges of organic carbon from eight contiguous small watersheds on the Atlantic Coastal Plain in Maryland for up to 24 yr. Six of these watersheds were second or third order with mixed-land-use, while two were first order (one completely forested and one highly dominated by cropland). These watersheds have perched aquifers, so all groundwater discharges as well as surface runoff were measured at V-notch weirs and flumes, which included volume-integrating flow-proportional samplers. Interannual variations in annual and seasonal precipitation during this study spanned approximately the range of 160 yr weather records in the region. Annual total organic carbon (TOC) area yields from the overall Rhode River watershed varied 8-fold, correlations with precipitation were highly significant, and a power function regression explained 54% of the variance in annual TOC fluxes. TOC fluxes were higher from upland forest than mixed land use, and highest from the cropland-dominated watershed. The fluxes from first order watersheds were more variable with precipitation. In the spring, TOC fluxes were highest and most correlated with precipitation, compared to other seasons. Precipitation volume also explained much of the variance in annual and spring TOC concentrations from upland forest and cropland, with concentrations three to five times higher in very wet years than in very dry years. Variation in winter and summer air temperature was correlated with TOC concentrations from forested watersheds, and linear regressions explained 19 to 42% of the variance in TOC. A regression model was used to construct graphical and tabular summaries. Particulate organic carbon and dissolved organic carbon (DOC) concentrations and the ratio of DOC to TOC were highly correlated with water discharge for a second order, mixed land use watershed, and power function regressions explained 21 to 43% of the variance. For the first order, single-land-use watersheds the ratio of DOC to TOC was also highly correlated with discharge. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Correll, DL (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. OI Weller, Donald/0000-0002-7629-5437 NR 56 TC 41 Z9 43 U1 1 U2 18 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD MAY PY 2001 VL 128 IS 1-2 BP 139 EP 159 DI 10.1023/A:1010337623092 PG 21 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA 419JJ UT WOS:000167945300009 ER PT J AU Ruostekoski, J Anglin, JR AF Ruostekoski, J Anglin, JR TI Creating vortex rings and three-dimensional skyrmions in Bose-Einstein condensates SO PHYSICAL REVIEW LETTERS LA English DT Article ID VORTICES AB We propose a method of generating a vortex ring in a Bose-Einstein condensate by means of electromagnetically induced atomic transitions. Some remnant population of atoms in a second internal state remains within the toroidal trap formed by the mean-field repulsion of the vortex ring. This population can he removed. or it can be made to flow around the torus (i.e.. within the vortex ring). If this flow has a unit topological winding number, the entire structure formed by the two condensates is an example of a three-dimensional Skyrmion texture. C1 Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02135 USA. RP Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. NR 17 TC 143 Z9 144 U1 2 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 30 PY 2001 VL 86 IS 18 BP 3934 EP 3937 DI 10.1103/PhysRevLett.86.3934 PG 4 WC Physics, Multidisciplinary SC Physics GA 429PJ UT WOS:000168525900003 PM 11328064 ER PT J AU Wong, GP Mair, RW Walsworth, RL Cory, DG AF Wong, GP Mair, RW Walsworth, RL Cory, DG TI Measurement of persistence in 1D diffusion SO PHYSICAL REVIEW LETTERS LA English DT Article ID ZERO-TEMPERATURE DYNAMICS; GAS-DIFFUSION; ISING-MODEL; EXPONENT; NMR; SURVIVAL; SPINS AB Using a novel NMR scheme we observed persistence in 1D gas diffusion. Analytical approximations and numerical simulations have indicated that for an initially random array of spins undergoing diffusion, the probability p(t) that the average spin magnetization in a given region has not changed sign (i.e., "persists") up to time t follows a power law t(-theta), where theta, depends on the dimensionality of the system. Using laser-polarized Xe-129 gas, we prepared an initial "quasirandom" 1D array of spin magnetization and then monitored the ensemble's evolution due to diffusion using real-time NMR imaging. Our measurements are consistent with analytical and numerical predictions of theta approximate to 0.12. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. MIT, Dept Nucl Engn, Cambridge, MA 02139 USA. RP Wong, GP (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 30 TC 36 Z9 36 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 30 PY 2001 VL 86 IS 18 BP 4156 EP 4159 DI 10.1103/PhysRevLett.86.4156 PG 4 WC Physics, Multidisciplinary SC Physics GA 429PJ UT WOS:000168525900058 PM 11328119 ER PT J AU Esry, BD Lin, CD Greene, CH Blume, D AF Esry, BD Lin, CD Greene, CH Blume, D TI Comment on "Efimov states for He-4 trimers?" SO PHYSICAL REVIEW LETTERS LA English DT Article ID HELIUM C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. RP Esry, BD (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. RI Greene, Chris/C-3821-2011; Lin, c d/D-7312-2012; Esry, Brett/H-7511-2013 OI Greene, Chris/0000-0002-2096-6385; Lin, c d/0000-0003-4847-8938; Esry, Brett/0000-0003-3207-8526 NR 6 TC 6 Z9 6 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 30 PY 2001 VL 86 IS 18 BP 4189 EP 4189 DI 10.1103/PhysRevLett.86.4189 PG 1 WC Physics, Multidisciplinary SC Physics GA 429PJ UT WOS:000168525900068 PM 11328129 ER PT J AU Haiman, Z Abel, T Madau, P AF Haiman, Z Abel, T Madau, P TI Photon consumption in minihalos during cosmological reionization SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; early universe; galaxies : evolution; galaxies : formation ID LIMIT ABSORPTION SYSTEMS; HIGH-REDSHIFT; INTERGALACTIC MEDIUM; GALAXY FORMATION; PRIMORDIAL GAS; UNIVERSE; DENSITY; QUASAR; SIGNATURES; DISCOVERY AB At the earliest epochs of structure formation in cold dark matter (CDM) cosmologies, the smallest nonlinear objects are the numerous small halos that condense with virial temperatures below similar to 10(4) K. Such "minihalos" are not yet resolved in large-scale three-dimensional cosmological simulations. Here we employ a semianalytic method, combined with three-dimensional simulations of individual minihalos, to examine their importance during cosmological reionization. We show that, depending on when reionization takes place, they potentially play an important role as sinks of ionizing radiation. If reionization occurs at sufficiently high redshifts (z(r) greater than or similar to 20), the intergalactic medium is heated to similar to 10(4) K and most minihalos never form. On the other hand, if z(r) less than or similar to 20, a significant fraction (greater than or similar to 10%) of all baryons have already collapsed into minihalos, and are subsequently removed from the halos by photoevaporation as the ionizing background flux builds up. We show that this process can require a significant budget of ionizing photons, exceeding the production by straightforward extrapolations back in time of known quasar and galaxy populations by a factor of up to similar to 10 and similar to3, respectively. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. RP Haiman, Z (reprint author), Princeton Univ Observ, Ivy Lane, Princeton, NJ 08544 USA. NR 44 TC 93 Z9 93 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 APR 26 PY 2001 VL 551 IS 2 BP 599 EP 607 DI 10.1086/320232 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 427AX UT WOS:000168383600001 ER PT J AU Jansen, RA Frankx, M Fabricant, D AF Jansen, RA Frankx, M Fabricant, D TI [O II] as a tracer of current star formation SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : ISM; stars : formation ID NEARBY FIELD GALAXIES; CFA REDSHIFT SURVEY; LUMINOSITY FUNCTION; SOUTHERN GALAXIES; DUST EXTINCTION; REGIONS; EMISSION; SPECTROSCOPY; ULTRAVIOLET; DIAGNOSTICS AB [O II] lambda 3727 is often used as a tracer of star formation at intermediate redshifts (z greater than or similar to 0.4), where H alpha is not easily observed. We use the spectrophotometric data of the Nearby Field Galaxy Survey to investigate the range and systematic variation in the observed [O II]/H alpha emission-line ratio as a function of galaxy luminosity at low redshift. We find that the observed [O II]/H alpha ratio varies by a factor of 7 at luminosities near M-B*. The [O II]/H alpha ratio is inversely correlated with luminosity. The scatter in the [O II]/H alpha ratio and the dependence of the ratio on luminosity are due in equal parts to reddening and to the metallicity-dependent excitation of the interstellar medium. The uncertainty in star formation rates derived from [O II] fluxes is therefore large. If H alpha cannot be observed, high signal-to-noise ratio H beta fluxes are much preferable to [O II] fluxes for deriving star formation rates. We present several purely empirical corrections for extinction. C1 Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. European Space Agcy, European Space Res & Technol Ctr, Dept Space Sci, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. Leiden Observ, NL-2300 RA Leiden, Netherlands. RP Jansen, RA (reprint author), Univ Groningen, Kapteyn Astron Inst, Postbus 800, NL-9700 AV Groningen, Netherlands. EM rjansen@astro.estec.esa.nl; franx@strw.leidenuniv.nl; dfabricant@cfa.harvard.edu NR 30 TC 89 Z9 89 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 APR 26 PY 2001 VL 551 IS 2 BP 825 EP 832 DI 10.1086/320228 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 427AX UT WOS:000168383600019 ER PT J AU Stoker, CR Cabrol, NA Roush, TR Moersch, J Aubele, J Barlow, N Bettis, EA Bishop, J Chapman, M Clifford, S Cockell, CS Crumpler, L Craddock, R De Hon, R Foster, T Gulick, V Grin, E Horton, K Hovde, G Johnson, JR Lee, PC Lemmon, MT Marshall, J Newsom, HE Ori, GG Reagan, M Rice, JW Ruff, SW Schreiner, J Sims, M Smith, PH Tanaka, K Thomas, HJ Thomas, G Yingst, RA AF Stoker, CR Cabrol, NA Roush, TR Moersch, J Aubele, J Barlow, N Bettis, EA Bishop, J Chapman, M Clifford, S Cockell, CS Crumpler, L Craddock, R De Hon, R Foster, T Gulick, V Grin, E Horton, K Hovde, G Johnson, JR Lee, PC Lemmon, MT Marshall, J Newsom, HE Ori, GG Reagan, M Rice, JW Ruff, SW Schreiner, J Sims, M Smith, PH Tanaka, K Thomas, HJ Thomas, G Yingst, RA TI The 1999 Marsokhod rover mission simulation at Silver Lake, California: Mission overview, data sets, and summary of results SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID PATHFINDER LANDING SITE; INFRARED MULTISPECTRAL SCANNER; NATURAL SURFACES; DEATH-VALLEY; MARS; FIELD; ROCKS; VOLCANISM; GEOLOGY; CLIMATE AB We report on a field experiment held near Silver Lake playa in the Mojave Desert in February 1999 with the Marsokhod rover. The payload (Descent Imager, PanCam, Mini-TES, and Robotic Arm Camera), data volumes, and data transmission/receipt windows simulated those planned for the Mars Surveyor mission selected for 2001. A central mast with a pan and tilt platform at 150 cm height carried a high-resolution color stereo imager to simulate the PanCam and a visible/near-infrared fiberoptic spectrometer (operating range 0.35-2.5 mum). Monochrome stereo navigation cameras were mounted on the mast and the front and rear of the rover near the wheels. A field portable infrared spectroradiometer (operating range 8-14 mum) simulated the Mini-TES. A Robotic Arm Camera, capable of close-up color imaging at 23 mum/pixel resolution, was used in conjunction with the excavation of a trench into the subsurface. The science team was also provided with simulated images from the Mars Descent Imager and orbital panchromatic and multispectral imaging of the site obtained with the French SPOT, airborne Thermal Infrared Mapping Spectrometer, and Landsat Thematic Mapper instruments. Commands sequences were programmed and sent daily to the rover, and data returned were limited to 40 Mbits per communication cycle. During the simulated mission, 12 commands were uplinked to the rover, it traversed similar to 90 m, six sites were analyzed, 11 samples were collected for laboratory analysis, and over 5 Gbits of data were collected. Twenty-two scientists, unfamiliar with the location of the field site, participated in the science mission from a variety of locations, accessing data via the World Wide Web. Remote science interpretations were compared with ground truth from the field and laboratory analysis of collected samples. Using this payload and mission approach, the science team synergistically interpreted orbital imaging and infrared spectroscopy, descent imaging, rover-based imaging, infrared spectroscopy, and microscopic imaging to deduce a consistent and largely correct interpretation of the geology, mineralogy, stratigraphy, and exobiology of the site. Use of imaging combined with infrared spectroscopy allowed source outcrops to be identified for local rocks on an alluvial fan. Different lithologies were distinguished both near the rover and at distances of hundreds of meters or more. Subtle differences such as a contact between dolomite and calcite were identified at a distance of 0.5 km. A biomarker for endolithic microbiota, a plausible life form to be found on Mars, was successfully identified. Microscopic imaging of soils extracted from the surface and subsurface allowed the mineralogy and fluvial history of the trench site to be deduced. The scientific productivity of this simulation shows that this payload and mission approach has high science value and would contribute substantially to achieving the goals of Mars exploration. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. New Mexico Museum Nat Hist & Sci, Albuquerque, NM 87104 USA. Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. Univ Iowa, Dept Geosci, Iowa City, IA 52242 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. Smithsonian Inst, Washington, DC 20560 USA. NE Louisiana Univ, Dept Geosci, Monroe, LA 71209 USA. Univ Hawaii Manoa, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. Univ Annunzio, Dipartimento Sci, I-65127 Pescara, Italy. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Univ Iowa, Dept Ind Engn, Iowa City, IA 52242 USA. RP Stoker, CR (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Lemmon, Mark/E-9983-2010; Moersch, Jeffrey/F-7189-2010; Craddock, Robert/B-3884-2013; Johnson, Jeffrey/F-3972-2015; OI Lemmon, Mark/0000-0002-4504-5136; ORI, Gian Gabriele/0000-0002-6460-1476 NR 54 TC 11 Z9 11 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 2001 VL 106 IS E4 BP 7639 EP 7663 DI 10.1029/1999JE001178 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 425JW UT WOS:000168288300008 ER PT J AU Knowlton, N AF Knowlton, N TI Sea urchin recovery from mass mortality: New hope for Caribbean coral reefs? SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Editorial Material ID DIADEMA-ANTILLARUM; PHASE-SHIFTS; COMMUNITY; RECRUITMENT; DISTURBANCE; DYNAMICS; DENSITY; BLOOMS; STATES; SCALE C1 Univ Calif San Diego, Scripps Inst Oceanog, Marine Biol Res Div 0202, La Jolla, CA 92093 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Knowlton, N (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Marine Biol Res Div 0202, La Jolla, CA 92093 USA. NR 28 TC 26 Z9 27 U1 3 U2 16 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 APR 24 PY 2001 VL 98 IS 9 BP 4822 EP 4824 DI 10.1073/pnas.091107198 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 425VC UT WOS:000168311500003 PM 11320228 ER PT J AU Arce, HG Goodman, AA AF Arce, HG Goodman, AA TI The mass-velocity and position-velocity relations in episodic outflows SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : jets and outflows; stars : formation; stars : mass loss ID MOLECULAR OUTFLOWS; BIPOLAR OUTFLOWS; STAR FORMATION; STELLAR JETS; DRIVEN; OUTBURSTS; MODELS; CLOUDS AB While observational evidence for the episodic nature of young stellar outflows continues to mount, existing numerical and theoretical models of molecular outflows assume that they are formed by the interaction of a nonepisodic wind from a young stellar object with an ambient cloud. In this Letter, we estimate and discuss the effects of episodicity on the mass-velocity and position-velocity relations observed in molecular outflows. We explain how many recent observational results disagree with the predictions of nonepisodic outflow models, and we offer simple explanations for the discrepancies. In particular, we discuss how an episodic stellar outflow can steepen the power-law slope of the mass-velocity relation in a molecular outflow. And we illustrate how an episodic outflow can produce multiple "Hubble wedges" in the position-velocity distribution of a molecular outflow. With a little more information than we have now, it may be possible to use the "fossil record" embedded in a molecular outflow's mass-velocity and position-velocity relations to reconstruct the history of a young stellar object's mass ejection episodes. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Arce, HG (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM harce@cfa.harvard.edu; agoodman@cfa.harvard.edu RI Goodman, Alyssa/A-6007-2010 OI Goodman, Alyssa/0000-0003-1312-0477 NR 27 TC 27 Z9 27 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 APR 20 PY 2001 VL 551 IS 2 BP L171 EP L174 DI 10.1086/320031 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 427BJ UT WOS:000168384700012 ER PT J AU McClintock, JE Garcia, MR Caldwell, N Falco, EE Garnavich, PM Zhao, P AF McClintock, JE Garcia, MR Caldwell, N Falco, EE Garnavich, PM Zhao, P TI A black hole greater than 6 M(circle dot) in the X-ray nova XTE J1118+480 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : individual (XTE J1118+480); X rays : stars ID OPTICAL COUNTERPART; ACCRETION DISC; XTE J1118+480; TRANSIENT; MASS; A0620-00; BINARY; DISCOVERY; CYGNI; STAR AB Observations of the quiescent X-ray nova XTE J1118+480 with the new 6.5 m Multiple Mirror Telescope have revealed that the velocity amplitude of the dwarf secondary is 698 +/- 14 km s(-1) and the orbital period of the system is 0.17013 +/- 0.00010 days. The implied value of the mass function, f(M) = 6.00 +/- 0.36 M., provides a hard lower limit on the mass of the compact primary that greatly exceeds the maximum allowed mass of a neutron star (similar to3 M.). Thus, we conclude that the compact primary is a black hole. Among the 11 dynamically established black hole X-ray novae, the large mass function of XTE J1118+480 is rivaled only by that of V404 Cyg. We estimate that the secondary supplies 34% +/- 8% of the total light at 5900 Angstrom and that its spectral type is in the range from K5 V to M1 V. A double-humped I-band light curve is probably due to ellipsoidal modulation, although this interpretation is not entirely secure because of an unusual 12 minute offset between the spectroscopic and photometric ephemerides. Assuming that the light curve is ellipsoidal, we present a provisional analysis that indicates that the inclination of the system is high and the mass of the black hole is correspondingly modest (M(1) less than or similar to 10 M.). The broad Balmer emission lines (FWHM = 2300-2900 km s(-1)) also suggest a high inclination. For the range of spectral types given above, we estimate a distance of kpc. 1.8 +/- 0.6 kpc. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Smithsonian Inst, FL Whipple Observ, Amado, AZ 85645 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RP McClintock, JE (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM jem@cfa.harvard.edu; mgarcia@cfa.harvard.edu; caldwell@flwo99.sao.arizona.edu; falco@cfa.harvard.edu; pgarnavi@nd.edu; pzhao@cfa.harvard.edu NR 30 TC 66 Z9 67 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 APR 20 PY 2001 VL 551 IS 2 BP L147 EP L150 DI 10.1086/320030 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 427BJ UT WOS:000168384700006 ER PT J AU Anderson, RP Handley, CO AF Anderson, RP Handley, CO TI A new species of three-toed sloth (Mammalia : Xenarthra) from Panama, with a review of the genus Bradypus SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID TORQUATUS XENARTHRA; BIOGEOGRAPHY; BRADYPODIDAE; EVOLUTION; PATTERNS; RATES AB Morphological and morphometric analyses of three-toed sloths (Bradypus) from the islands of Bocas del Toro reveal rapid differentiation of several populations during the Holocene. These islands, lying off the Caribbean coast of western Panama, were separated from the adjacent mainland by rising sea levels during the past 10,000 years. The sequence of island formation and the approximate ages of the islands are known. In at least four independent events, sloths on five of the islands evolved smaller size following insularization. Sloths on the younger islands remain conspecific with mainland populations of Bradypus variegatus. On Isla Escudo de Veraguas-the oldest and most remote island of the archipelago-however, the three-toed sloth has differentiated to the species level, and we here describe it as Bradypus pygmaeus. We provide updated diagnoses and distributions for the species of Bradypus, including a key to the genus. C1 Univ Kansas, Museum Nat Hist, Lawrence, KS 66045 USA. Univ Kansas, Biodivers Res Ctr, Lawrence, KS 66045 USA. Univ Kansas, Dept Ecol & Evolutionary Biol, Lawrence, KS 66045 USA. Smithsonian Inst, Natl Museum Nat Hist, Div Mammals, Washington, DC 20560 USA. RP Anderson, RP (reprint author), Univ Kansas, Museum Nat Hist, 1345 Jayhawk Blvd, Lawrence, KS 66045 USA. NR 72 TC 39 Z9 45 U1 4 U2 73 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 1 EP 33 PG 33 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000001 ER PT J AU Suarez, W Olson, SL AF Suarez, W Olson, SL TI A remarkable new species of small falcon from the Quaternary of Cuba (Aves : Falconidae : Falco) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB An enigmatic small falcon, Falco kurochkini, new species, is described from postcranial bones from several Quaternary sites in western and central Cuba. It was approximately intermediate in size between F. sparverius and F. columbarius but had proportionately longer and more slender leg elements than any living species of Falco. It is hypothesized that F. kurochkini may have been terrestrial, pursuing prey on foot, and that its extinction could have been related to terrestrial nesting habits as well. C1 Museo Nacl Hist Nat, La Habana 10100, Cuba. Natl Museum Nat Hist, Dept Vertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. RP Suarez, W (reprint author), Museo Nacl Hist Nat, Obispo 61,Plaza Armas, La Habana 10100, Cuba. NR 14 TC 6 Z9 6 U1 0 U2 1 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 34 EP 41 PG 8 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000002 ER PT J AU Graves, GR AF Graves, GR TI Diagnoses of hybrid hummingbirds (Aves : Trochilidae). 9. Confirmation of the hybrid origin of Coeligena purpurea Gould, 1854 SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID INTERGENERIC HYBRID AB Coeligena purpurea Gould, 1854 is shown to be a hybrid between Coeligena coeligena and Coeligena prunellei. The geographic distribution of the parental species suggests that the two hybrid specimens were collected in the Eastern Cordillera of the Colombian Andes. The hybrids exhibit a blended mosaic of plumage characters of the postulated parental species. External measurements of the hybrids fall within the cumulative ranges of characters of the parental species. C1 Smithsonian Inst, Museum Natl Hist Nat, Dept Vertebrate Zool, Washington, DC 20560 USA. RP Graves, GR (reprint author), Smithsonian Inst, Museum Natl Hist Nat, Dept Vertebrate Zool, Washington, DC 20560 USA. NR 32 TC 0 Z9 0 U1 0 U2 2 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 42 EP 50 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000003 ER PT J AU Liao, YL Pawson, DL AF Liao, YL Pawson, DL TI Dendrochirote and dactylochirote sea cucumbers (Echinodermata : Holothuroidea) of China, with descriptions of eight new species SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB The dendrochirote and dactylochirote holothurian fauna of China is now known to comprise 56 species in 16 genera. An annotated checklist of species is included here. Eight species are described as new: Actinocucumis chinensis, Phyllophorus (Phyllothuria) donghaiensis, P. (Isophyllophorus) orientalis, Neothyonidium spiniferum, Stolus crassus, S. micronodosus, Thyone purpureopunctata and T. sinensis. Phyllophorus (Isophyllophorus), a new subgenus, is also diagnosed. Preliminary analysis reveals that affinities of the dendrochirote/dactylochirote fauna lie with the tropical Indo-West-Pacific, for approximately 70% of the species are more or less widely distributed in the Indo-West-Pacific. Ten species are now known from the Yellow Sea, 26 from the East China Sea, and 39 from the South China Sea. C1 Acad Sinica, Inst Oceanol, Qingdao 266071, Peoples R China. Smithsonian Inst, Natl Museum Nat Hist, Washington, DC 20560 USA. RP Liao, YL (reprint author), Acad Sinica, Inst Oceanol, 7 Nanhai Rd, Qingdao 266071, Peoples R China. NR 56 TC 5 Z9 6 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X EI 1943-6327 J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 58 EP 90 PG 33 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000005 ER PT J AU Flint, OS AF Flint, OS TI Diplectroninae of Sri Lanka (Trichoptera : Hydropsychidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB The subfamily Diplectroninae of Sri Lanka is revised. The male genitalia of the lectotypes of the three described species, Diplectrona papilionacea (Hagen), D. maligna (Hagen) and D. taprobanes (Hagen), are figured and diagnostic notes and distributions given. Three new species, D. malickyi, D. longistyla and D, ingens are described, figured and distributions presented, and D. kirimaduhela Schmid is newly synonymized with D. maligna. The genus Diplectronella Ulmer, type species D. taprobanes, is synonymized with Diplectrona Westwood, type species D. felix McLachlan. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, Washington, DC 20560 USA. RP Flint, OS (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, Washington, DC 20560 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 91 EP 103 PG 13 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000006 ER PT J AU Galil, BS Manning, RB AF Galil, BS Manning, RB TI A new geryonid crab from the Amirante Basin, western Indian Ocean (Crustacea : Decapoda : Brachyura) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Two deep water geryonid crabs, Chaceon crosnieri Manning & Holthuis, and C. goreni, a new species, are reported from the Amirante Basin. Chaceon goreni, the seventh species of the genus to be recognized from the western Indian Ocean, is described from material collected in 1400 m off Alphonse Island. It most closely resembles C. collettei Manning, in having a spine externally on the carpus of the cheliped; but it is distinguished in having longer, more slender frontal and anterolateral spines, and proportionately longer, more slender pereopods. C1 Israel Oceanog & Limnol Res, Natl Inst Oceanog, IL-31080 Haifa, Israel. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Galil, BS (reprint author), Israel Oceanog & Limnol Res, Natl Inst Oceanog, POB 8030, IL-31080 Haifa, Israel. NR 7 TC 1 Z9 2 U1 1 U2 1 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 104 EP 108 PG 5 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000007 ER PT J AU Kensley, B Bruce, NL AF Kensley, B Bruce, NL TI Redescription of Dynameniscus carinatus (Richardson, 1900) (Crustacea : Isopoda : Sphaeromatidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID AUSTRALIA AB Dynameniscus carinatus, originally described one hundred years ago from a single female from deep water off Georgia, U.S.A., is redescribed, based on an additional male and two females, all from the Caribbean. The genus is redefined, and its affinities briefly discussed. Its subfamilial placement remains uncertain, however, given a number of unusual features in the mouthparts, pleopods, and uropods. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. Natl Inst Water & Atmospher Res, Wellington, New Zealand. RP Kensley, B (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 18 TC 2 Z9 2 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 188 EP 196 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000016 ER PT J AU Ivanenko, VN Ferrari, FD Smurov, AV AF Ivanenko, VN Ferrari, FD Smurov, AV TI Nauplii and copepodids of Scottomyzon gibberum (Copepoda : Siphonostomatoida : Scottomyzotidae, a new family), a symbiont of Asterias rubens (Asteroidea) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID SCOTT; SEA; ASTEROCHERIDAE; NUMBERS; BELIZE AB Naupliar and copepodid stages of Scottomyzon gibberum (Scott & Scott, 1894) associated with the starfish Asterias rubens Linnaeus, 1767 in the North and White Seas were collected from the host or reared in the laboratory. There are six copepodid stages and four naupliar stages. Changes in size and proportions of the prosome of adult females result from an expansion of unsclerotized integument along the margins of the shield of the cephalothorax and tergites of the second and third thoracic somites. The monotypic genus Scottomyzon Giesbrecht, 1897 is transferred to a new family Scottomyzontidae on the basis of a S-segmented abdomen for adults of both sexes, paired dorsolateral gonopores near the posterior margin of somite, paired ventral copulatory pores near the middle of somite, and sexual dimorphism in oral siphon. C1 Moscow MV Lomonosov State Univ, Fac Biol, Dept Invertebrate Zool, Moscow 119899, Russia. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Ivanenko, VN (reprint author), Moscow MV Lomonosov State Univ, Fac Biol, Dept Invertebrate Zool, Moscow 119899, Russia. RI Ivanenko, Viatcheslav/B-8198-2008 OI Ivanenko, Viatcheslav/0000-0003-1255-0491 NR 63 TC 16 Z9 17 U1 0 U2 1 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 237 EP 261 PG 25 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000021 ER PT J AU Hershler, R Gustafson, DL AF Hershler, R Gustafson, DL TI First record for springsnails (Mollusca : Hydrobiidae : Pyrgulopsis) from the northern Rocky Mountains SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID YELLOWSTONE HOTSPOT WAKE; SOUTHWESTERN MONTANA; TECTONICS AB Pyrgulopsis bedfordensis, new species, from southwest Montana, differs from other congeners having an enlarged genial lobe by its unique pattern of genial ornament, consisting of a transverse terminal gland and a raised gland on the inner edge of the lobe. This species is locally endemic in the headwater region of the Missouri River basin. Origin of this novelty is attributed to vicariance associated with Neogene migration of the continental divide. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. Montana State Univ, Dept Ecol, Bozeman, MT 59717 USA. RP Hershler, R (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 35 TC 7 Z9 7 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 19 PY 2001 VL 114 IS 1 BP 297 EP 308 PG 12 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 428MG UT WOS:000168465000026 ER PT J AU Vikhlinin, A Markevitch, M Murray, SS AF Vikhlinin, A Markevitch, M Murray, SS TI A moving cold front in the intergalactic medium of A3667 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general galaxies : clusters : individual (Abell 3667); magnetic fields; shock waves; X-rays : galaxies ID EXTENDED RADIO-EMISSION; TEMPERATURE STRUCTURE; CLUSTER; MERGER; ABELL-3667 AB We present results from a Chandra observation of the central region of the galaxy cluster A3667 with emphasis on the prominent sharp X-ray brightness edge spanning 0.5 Mpc near the cluster core. Our temperature map shows large-scale nonuniformities characteristic of the ongoing merger, in agreement with earlier ASCA results. The brightness edge turns out to be a boundary of a large cool gas cloud moving through the hot ambient gas, very similar to the "cold fronts" discovered by Chandra in A2142. The higher quality of the A3667 data allows the direct determination of the cloud velocity. At the leading edge of the cloud, the gas density abruptly increases by a factor of 3.9 +/- 0.8, while the temperature decreases by a factor of 1.9 +/- 0.2 (from 7.7 to 4.1 keV). The ratio of the gas pressures inside and outside the front shows that the cloud moves through the ambient gas at near-sonic velocity, M = 1 +/- 0.2 or v = 1400 +/- 300 km s(-1). In front of the cloud, we observe the compression of the ambient gas with an amplitude expected for such a velocity. A smaller surface brightness discontinuity is observed further ahead, similar to 350 kpc in front of the cloud. We suggest that it corresponds to a weak bow shock, implying that the cloud velocity may be slightly supersonic. Given all the evidence, the cold front appears to delineate the remnant of a cool subcluster that recently has merged with A3667. The cold front is remarkably sharp. The upper limit on its width, 3."5 or 5 kpc, is several times smaller than the Coulomb mean free path. This is a direct observation of suppression of the transport processes in the intergalactic medium, most likely by magnetic fields. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Space Res Inst, Moscow, Russia. RP Vikhlinin, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 23 TC 281 Z9 281 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 APR 18 PY 2001 VL 551 IS 1 BP 160 EP 171 DI 10.1086/320078 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AF UT WOS:000168152200014 ER PT J AU Worrall, DM Birkinshaw, M AF Worrall, DM Birkinshaw, M TI The X-ray emission of 3C 346 and its environment SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (3C 346); galaxies : jets; radiation mechanisms : nonthermal; X-rays : galaxies ID RADIO GALAXIES; VLBI OBSERVATIONS; COMPLETE SAMPLE; GAS; PKS-0637-752; CLUSTERS; NUCLEI; JET AB We present a detailed spectral and spatial analysis of the X-ray properties of the compact and unusual radio galaxy 3C 346, combining information from ROSAT and ASCA. The dominant component of X-ray emission (similar to 10(44) ergs s(-1) in each of the 0.5-3 keV and 2-10 keV bands) is unresolved and not heavily absorbed (intrinsic N-H less than or similar to 2 x 10(21) cm(-2)), with evidence for variability of 32% +/- 13% over 18 months. We relate the X-ray emission to radio structures on both milliarcsecond scales and the arcsecond scales which Chandra can resolve. The absence of X-ray absorption, and the radio/optical/X-ray colors, when combined with previous radio evidence that the source is a foreshortened FR II, suggest that the radio jets are seen at an angle to the line of sight of about 30 degrees, intermediate between the radio galaxy and quasar classes. Roughly a third of the soft X-ray emission is from a cluster atmosphere, for which we measure a temperature of 1.9(-0.7)(+1.3) keV, making this the second low-redshift (z < 0.2) powerful radio galaxy, after Cyg A, with a measured cluster temperature. At a jet angle of 30 degrees, all the radio structures lie within the core radius of the cluster, for which the cooling time is sufficiently long that there is no reason to expect the presence of a cooling flow. The radio lobes of 3C 346 are roughly in pressure balance with the external medium under the assumptions that the energy densities in the magnetic field and radiating particles balance and that a source of excess pressure in the radio lobes, commonly invoked in other radio galaxies, is absent here. C1 Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. RP Worrall, DM (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 35 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 APR 18 PY 2001 VL 551 IS 1 BP 178 EP 185 DI 10.1086/320068 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AF UT WOS:000168152200016 ER PT J AU Alexander, T Loeb, A AF Alexander, T Loeb, A TI Enhanced microlensing by stars around the black hole in the Galactic center SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxy : center; galaxy : stellar content; gravitational lensing; infrared : stars ID LUMINOSITY FUNCTION; GRAVITATIONAL LENS; PROPER MOTIONS; LIGHT CURVES; MILKY-WAY; PLANETS; GALAXY; EVENTS; BULGE; MODEL AB The effect of stars on the lensing properties of the supermassive black hole in the Galactic center is similar to the effect of planets on microlensing by a star. We show that the dense stellar cluster around Sgr A* increases by factors of a few the probability of high-magnification lensing events of a distant background source by the black hole. Conversely, the gravitational shear of the black hole changes and enhances the microlensing properties of the individual stars. The effect is largest when the source image lies near the Einstein radius of the black hole for a source at infinity). We estimate that the (1."75+/-0."20 probability of observing at least one distant background star, which is magnified by a factor greater than 5 in any infrared snapshot of the inner similar to2" of the Galactic center, is similar to1% with a K-band detection threshold of 20 mag. The largest source of uncertainty in this estimate is the luminosity function of the background stars. The gravitational shear of the black hole lengthens the duration of high-magnification events near the Einstein radius up to a few months and introduces a large variety of light-curve shapes that are different from those of isolated microlenses. Identification of such events by image subtraction can be used to probe the mass function, density, and velocity distributions of faint stars near the black hole, which are not detectable otherwise. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Alexander, T (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 32 TC 25 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 18 PY 2001 VL 551 IS 1 BP 223 EP 230 DI 10.1086/320087 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AF UT WOS:000168152200020 ER PT J AU Wright, MCH Coil, AL McGary, RS Ho, PTP Harris, AI AF Wright, MCH Coil, AL McGary, RS Ho, PTP Harris, AI TI Molecular tracers of the central 12 parsecs of the Galactic center SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy : center; ISM : molecules; radio lines : ISM; techniques : interferometric ID SAGITTARIUS-A COMPLEX; APERTURE SYNTHESIS OBSERVATIONS; HIGH-RESOLUTION OBSERVATIONS; CENTER REGION; ROTATION CURVE; NEUTRAL-GAS; SGR-A; CLOUDS; GALAXY; SUBMILLIMETER AB We have used the BIMA array to image the Galactic center with a 19 pointing mosaic in HCN(1-0), HCO+ (1-0), and H 42 alpha emission with 5 km s(-1) velocity resolution and 13" x 4" angular resolution. The 5' field includes the circumnuclear ring (CND) and parts of the 20 and 50 km s(-1) clouds. HCN(1-0) and HCO+ trace the CND and nearby giant molecular clouds, while the H 42 alpha emission traces the ionized gas in Sgr A West. We find that the CND has a definite outer edge in HCN and HCO+ emission at similar to 45" radius and appears to be composed of two or three distinct streams of molecular gas rotating around the nucleus. Outside the CND, HCN and HCO+ trace dense clumps of high-velocity gas in addition to optically thick emission from the 20 and 50 km s(-1) clouds. A molecular ridge of compressed gas and dust, traced in NH3 emission and self-absorbed HCN and HCO+, wraps around the eastern edge of Sgr A East. Just inside this ridge are several arcs of gas that have been accelerated by the impact of Sgr A East with the 50 km s(-1) cloud. HCN and HCO+ emission trace the extension of the northern arm of Sgr A West, which appears to be an independent stream of neutral and ionized gas and dust originating outside the CND. Broad line widths and OH maser emission mark the intersection of the northern arm and the CND. Comparison to previous NH3 and 1.2 mm dust observations shows that HCN and HCO+ preferentially trace the CND and are weaker tracers of the GMCs than NH3 and dust. We discuss possible scenarios for the emission mechanisms and environment at the Galactic center that could explain the differences in these images. C1 Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Maryland, College Pk, MD 20742 USA. RP Wright, MCH (reprint author), Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. NR 48 TC 52 Z9 53 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 APR 18 PY 2001 VL 551 IS 1 BP 254 EP 268 DI 10.1086/320089 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AF UT WOS:000168152200024 ER PT J AU Di Stefano, R Greiner, J Murray, S Garcia, M AF Di Stefano, R Greiner, J Murray, S Garcia, M TI A new way to detect massive black holes in galaxies: The stellar remnants of tidal disruption SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (M31); X-rays : stars ID X-RAY OUTBURST; MAGELLANIC CLOUD; HELIUM STARS; EVOLUTION; NGC-5905; IC-3599; GIANT; RATES AB We point out that the tidal disruption of a giant may leave a luminous (10(35)-10(39) ergs s(-1)), hot (10-100 eV) stellar core. The "supersoft" source detected by Chandra at the center of M31 may be such a core; whether or not it is, the observations have shown that such a core is detectable, even in the center of a galaxy. We therefore explore the range of expected observational signatures and how they may be used to (1) test the hypothesis that the M31 source is a remnant of tidal stripping and (2) discover evidence of black holes and disruption events in other galaxies. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Tufts Univ, Dept Phys & Astron, Medford, MA 02155 USA. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. RP Di Stefano, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 39 TC 19 Z9 19 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 APR 18 PY 2001 VL 551 IS 1 BP L37 EP L40 DI 10.1086/319835 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AR UT WOS:000168153300009 ER PT J AU Granot, J Loeb, A AF Granot, J Loeb, A TI Chromatic signatures in the microlensing of gamma-ray burst afterglows SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; gravitational lensing ID COSMOLOGICAL DENSITY; LIGHT CURVES; OBJECTS; SPECTRA; SIZE AB We calculate the radial surface brightness profile of the image of a gamma-ray burst (GRB) afterglow. The afterglow spectrum consists of several power-law segments separated by breaks. The image profile changes considerably across each of the spectral breaks. It also depends on the density profile of the ambient medium into which the GRB fireball propagates. Gravitational microlensing by an intervening star can resolve the afterglow image. We calculate the predicted magnification history of GRB afterglows as a function of observed frequency and ambient medium properties. We find that intensive monitoring of a microlensed afterglow light curve can be used to reconstruct the parameters of the fireball and its environment and provide constraints on particle acceleration and magnetic field amplification in relativistic blast waves. C1 Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Granot, J (reprint author), Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. NR 22 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 APR 18 PY 2001 VL 551 IS 1 BP L63 EP L66 DI 10.1086/319843 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AR UT WOS:000168153300015 ER PT J AU Groot, PJ AF Groot, PJ TI Evolution of spiral shocks in U Geminorum during outburst SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; line : profiles; novae, cataclysmic variables; shock waves; stars : individual (U Geminorum) ID ACCRETION DISKS AB Time-resolved spectroscopic observations of U Geminorum during its 2000 March outburst show strong spiral shocks in the accretion disk. During the plateau at maximum brightness, the spiral shocks contribute similar to 14% to the total He II flux. The two arms of the spiral show a distinctly different evolution during the outburst and decline, which indicates an asymmetric evolution in the disk. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Groot, PJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Groot, Paul/K-4391-2016 OI Groot, Paul/0000-0002-4488-726X NR 15 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 APR 18 PY 2001 VL 551 IS 1 BP L89 EP L92 DI 10.1086/319826 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AR UT WOS:000168153300021 ER PT J AU Joy, M LaRoque, S Grego, L Carlstrom, JE Dawson, K Ebeling, H Holzapfel, WL Nagai, D Reese, ED AF Joy, M LaRoque, S Grego, L Carlstrom, JE Dawson, K Ebeling, H Holzapfel, WL Nagai, D Reese, ED TI Sunyaev-Zeldovich effect imaging of massive clusters of galaxies at redshift z > 0.8 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; galaxies : clusters : individual (Cl J0152.7-1357, Cl J1226.9+3332, MS 1054.4-0321); techniques : interferometric ID X-RAY-CLUSTERS; MS-1054-03; DENSITY; ABUNDANCE; UNIVERSE; Z=0.83 AB We present Sunyaev-Zeldovich effect (SZE) imaging observations of three distant (z > 0.8) and highly X-ray luminous clusters of galaxies, Cl J1226.9+3332, Cl J0152.7-1357, and MS 1054.4-0321. Two of the clusters, Cl J1226.9+3332 and Cl J0152.7-1357, were recently discovered in deep ROSAT X-ray images. Their high X-ray luminosity suggests that they are massive systems, which, if confirmed, would provide strong constraints on the cosmological parameters of structure formation models. Our SZE data provide confirmation that they are massive clusters similar to the well-studied cluster MS 1054.4-0321. Assuming the clusters have the same gas mass fraction as that derived from SZE measurements of 18 known massive clusters, we are able to infer their mass and electron temperature from the SZE data. The derived electron temperatures are 9.8(-1.9)(+4.7), 8.7(-1.8)(+4.1), and 10.4(-2.0)(+5.0) keV, respectively, and we infer total masses of similar to2 x 10(14) h(100)(-1) M. within a radius of 65 " (340 h(100)(-1) kpc) for all three clusters. For Cl J0152.7-1357 and MS 1054.4-0321, we find good agreement between our SZE-derived temperatures and those inferred from X-ray spectroscopy. No X-ray-derived temperatures are available for Cl J1226.9+3332, and thus the SZE data provide the first confirmation that it is indeed a massive system. The demonstrated ability to determine cluster temperatures and masses from SZE observations without access to X-ray data illustrates the power of using deep SZE surveys to probe the distant universe. C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Joy, M (reprint author), NASA, George C Marshall Space Flight Ctr, Dept Space Sci, SD50, Huntsville, AL 35812 USA. RI Holzapfel, William/I-4836-2015 NR 32 TC 32 Z9 32 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 APR 18 PY 2001 VL 551 IS 1 BP L1 EP L4 DI 10.1086/319833 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AR UT WOS:000168153300001 ER PT J AU Mathur, S Matt, G Green, PJ Elvis, M Singh, KP AF Mathur, S Matt, G Green, PJ Elvis, M Singh, KP TI Surprises from a deep ASCA spectrum of the broad absorption line quasar PHL 5200 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : absorption lines; quasars : individual (PHL 5200); X-rays : galaxies ID X-RAY-ABSORPTION; PHL-5200 AB We present a deep (similar to 85 ks) ASCA observation of the prototype broad absorption line quasar (BALQSO) PHL 5200. This is the best X-ray spectrum of a BALQSO yet. We find the following: (1) The source is not intrinsically X-ray weak. (2) The line-of-sight absorption is very strong, with N-H = 5 x 10(23) cm(-2). (3) The absorber does not cover the source completely; the covering fraction is approximate to 90%. This is consistent with the large optical polarization observed in this source, implying multiple lines of sight. The most surprising result of this observation is that (4) the spectrum of this BALQSO is not exactly similar to other radio-quiet quasars. The hard X-ray spectrum of PHL 5200 is steep, with the power-law spectral index alpha approximate to 1.5. This is similar to the steepest hard X-ray slopes observed so far. At low redshifts, such steep slopes are observed in narrow-line Seyfert 1 (NLS1) galaxies, believed to be accreting at a high Eddington rate. This observation strengthens the analogy between BALQSOs and NLS1 galaxies and supports the hypothesis that BALQSOs represent an early evolutionary state of quasars. It is well accepted that the orientation to the line of sight determines the appearance of a quasar; age seems to play a significant role as well. C1 Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Roma Tre, Dept Fis, I-00146 Rome, Italy. Tata Inst Fundamental Res, Dept Astron & Astrophys, Mumbai 400005, India. RP Mathur, S (reprint author), Ohio State Univ, Dept Astron, 140 W 18th Ave, Columbus, OH 43210 USA. NR 28 TC 10 Z9 10 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 APR 18 PY 2001 VL 551 IS 1 BP L13 EP L16 DI 10.1086/319841 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423AR UT WOS:000168153300004 ER PT J AU Theron, E Hawkins, K Bermingham, E Ricklefs, RE Mundy, NI AF Theron, E Hawkins, K Bermingham, E Ricklefs, RE Mundy, NI TI The molecular basis of an avian plumage polymorphism in the wild: A melanocortin-1-receptor point mutation is perfectly associated with the melanic plumage morph of the bananaquit, Coereba flaveola SO CURRENT BIOLOGY LA English DT Article ID STIMULATING HORMONE; COAT COLOR; MSH RECEPTOR; RED HAIR; PIGMENTATION; MC1R; GENE; 1-RECEPTOR; EXTENSION; LOCUS AB Background: Evolution depends on natural selection acting on phenotypic variation, but the genes responsible for phenotypic variation in natural populations of vertebrates are rarely known. The molecular genetic basis for plumage color variation has not been described in any wild bird. Bananaquits (Coereba flaveola) are small passerine birds that occur as two main plumage variants, a widespread yellow morph with dark back and yellow breast and a virtually all black melanic morph. A candidate gene for this color difference is the melanocortin-1 receptor (MC1R), a key regulator of melanin synthesis in feather melanocytes. Results: We sequenced the MC1R gene from four Caribbean populations of the bananaquit; two populations of the yellow morph and two populations containing both the yellow morph and the melanic morph. A point mutation resulting in the replacement of glutamate with lysine was present in at least one allele of the MC1R gene in all melanic birds and was absent in all yellow morph birds. This substitution probably causes the color variation, as the same substitution is responsible for melanism in domestic chickens and mice. The evolutionary relationships among the MC IR haplotypes show that the melanic alleles on Grenada and St. Vincent had a single origin. The low prevalence of nonsynonymous substitutions among yellow haplotypes suggests that they have been under stabilizing selection, whereas strong selective constraint on melanic haplotypes is absent. Conclusions: We conclude that a mutation in the MC1R is responsible for the plumage polymorphism in a wild bird population and that the melanic MC1R alleles in Grenada and St. Vincent bananaquit populations have a single evolutionary, origin from a yellow allele. C1 Univ Oxford, Dept Biol Anthropol, Oxford OX2 6QS, England. Smithsonian Trop Res Inst, Balboa, Panama. Univ Missouri, Dept Biol, St Louis, MO 63121 USA. RP Mundy, NI (reprint author), Univ Oxford, Dept Biol Anthropol, Oxford OX2 6QS, England. NR 26 TC 172 Z9 178 U1 4 U2 41 PU CELL PRESS PI CAMBRIDGE PA 1100 MASSACHUSETTES AVE,, CAMBRIDGE, MA 02138 USA SN 0960-9822 J9 CURR BIOL JI Curr. Biol. PD APR 17 PY 2001 VL 11 IS 8 BP 550 EP 557 DI 10.1016/S0960-9822(01)00158-0 PG 8 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 433ET UT WOS:000168746800018 PM 11369199 ER PT J AU Kalfatovic, MR AF Kalfatovic, MR TI Eric ischl, 1970-2000. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC 20560 USA. RP Kalfatovic, MR (reprint author), Smithsonian Inst Lib, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD APR 15 PY 2001 VL 126 IS 7 BP 82 EP 82 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 422ZX UT WOS:000168151400029 ER PT J AU Stewart, ED Cohn, JD AF Stewart, ED Cohn, JD TI Inflationary models with a flat potential enforced by non-Abelian discrete gauge symmetries SO PHYSICAL REVIEW D LA English DT Article ID COSMOLOGICAL MODULI PROBLEM; SUPERHEAVY DARK-MATTER; SUPERSYMMETRY BREAKING THEORIES; AFFLECK-DINE BARYOGENESIS; LARGE-SCALE STRUCTURE; THERMAL INFLATION; HYBRID INFLATION; OBSERVATIONAL CONSTRAINTS; DENSITY PERTURBATIONS; QUANTUM CORRECTIONS AB Non-Abelian discrete gauge symmetries can provide the inflaton with a flat potential even when one takes into account gravitational strength effects. The discreteness of the symmetries also provide special field values where inflation can end via a hybrid-type mechanism. An interesting feature of this method is that it can naturally lead to extremely flat potentials and so, in principle, to inflation at unusually low energy scales. Two examples of effective field theories with this mechanism are given: one with a hybrid exit and one with a mutated hybrid exit. They include an explicit example in which the single field consistency condition is violated. C1 NASA, Fermilab Astrophys Grp, FNAL, Batavia, IL 60510 USA. Korea Adv Inst Sci & Technol, Dept Phys, Taejon 305701, South Korea. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Stewart, ED (reprint author), NASA, Fermilab Astrophys Grp, FNAL, Batavia, IL 60510 USA. EM ewan@kaist.ac.kr; jcohn@cfa.harvard.edu RI Stewart, Ewan/C-1565-2011 NR 70 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 2001 VL 63 IS 8 AR 083519 DI 10.1103/PhysRevD.63.083519 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 423XQ UT WOS:000168203400028 ER PT J AU Cherepkov, NA Semenov, SK AF Cherepkov, NA Semenov, SK TI Non-dipole effects in spin polarization of photoelectrons from Xe 4p and 5p shells SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ANGULAR-DISTRIBUTION; PHOTOIONIZATION; PHOTOEMISSION; MULTIPOLE; ATOMS AB The contribution of electric-dipole-electric-quadrupole interference terms (the lowest-order non-dipole corrections) to the spin polarization of photoelectrons ejected from atomic np-shells is analysed theoretically. The numerical calculations in the non-relativistic random phase approximation with exchange for Xe 4p and 5p shells show that these corrections even at low photon energies (below 350 eV) can be observed, especially in the regions where the spin polarization parameters in the electric-dipole approximation are approaching zero values. For the 5p shell the contribution of non-dipole terms to the spin polarization of photoelectrons is of the order of a few per cent, while for the 4p shell it can be as large as 15%. This changes completely the shapes of the corresponding angular dependences near the ionization threshold of the 4p shell. Possible experimental geometries are proposed, which allow an easy observation of these non-dipole effects. C1 Harvard Smithsonian Ctr Astrophys, ITAMP, Cambridge, MA 02138 USA. State Univ Aerosp Instrumentat, St Petersburg 190000, Russia. RP Cherepkov, NA (reprint author), Harvard Smithsonian Ctr Astrophys, ITAMP, 60 Garden St, Cambridge, MA 02138 USA. NR 21 TC 15 Z9 15 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD APR 14 PY 2001 VL 34 IS 7 BP L211 EP L217 DI 10.1088/0953-4075/34/7/102 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 428JE UT WOS:000168457900002 ER PT J AU Murray, N Holman, M AF Murray, N Holman, M TI The role of chaotic resonances in the Solar System SO NATURE LA English DT Review ID MEAN MOTION RESONANCES; OUTER ASTEROID BELT; UPSILON ANDROMEDAE; 3/1 COMMENSURABILITY; PLANETARY SYSTEM; EARTHS OBLIQUITY; KIRKWOOD GAP; ORIGIN; METEORITES; STABILITY AB Our understanding of the Solar System has been revolutionized over the past decade by the finding that the orbits of the planets are inherently chaotic. In extreme cases, chaotic motions can change the relative positions of the planets around stars, and even eject a planet from a system. Moreover, the spin axis of a planet-Earth's spin axis regulates our seasons-may evolve chaotically, with adverse effects on the climates of otherwise biologically interesting planets. Some of the recently discovered extrasolar planetary systems contain multiple planets, and it is likely that some of these are chaotic as well. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. RP Holman, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM mholman@cfa.harvard.edu NR 56 TC 34 Z9 35 U1 1 U2 4 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 12 PY 2001 VL 410 IS 6830 BP 773 EP 779 DI 10.1038/35071000 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 420TT UT WOS:000168021900044 PM 11298438 ER PT J AU Allen, SW Fabian, AC Johnstone, RM Arnaud, KA Nulsen, PEJ AF Allen, SW Fabian, AC Johnstone, RM Arnaud, KA Nulsen, PEJ TI ASCA and ROSAT observations of nearby cluster cooling flows SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : clusters : general; cooling flows; intergalactic medium; X-rays : galaxies ID INTRACLUSTER MEDIUM ENRICHMENT; RAY-LUMINOUS CLUSTERS; FAR-INFRARED EMISSION; FLUX-LIMITED SAMPLE; X-RAY; STAR-FORMATION; GALAXY CLUSTERS; COLD CLOUDS; METALLICITY GRADIENTS; PERSEUS CLUSTER AB We present a detailed analysis of the X-ray properties of the cooling flows in a sample of nearby, X-ray-bright clusters of galaxies using high-quality ASCA spectra and ROSAT X-ray images. We demonstrate the need for multiphase models to consistently explain the spectral and imaging X-ray data for the clusters. The mass deposition rates of the cooling flows, independently determined from the ASCA spectra and ROSAT images, exhibit reasonable agreement. We confirm the presence of intrinsic X-ray absorption in the clusters using a variety of spectral models. We also report detections of 100-mum infrared emission, spatially coincident with the cooling flows, in several of the systems studied. The observed infrared fluxes and flux limits are in good agreement with the predicted values owing to reprocessed X-ray emission from the cooling flows. We present precise measurements of the abundances of iron, magnesium, silicon and sulphur in the central regions of the Virgo and Centaurus clusters, Our results firmly favour models in which a high mass fraction (70-80 per cent) of the iron in the X-ray gas in these regions originates from Type Ia supernovae. Finally, we present a series of methods which may be used to estimate the ages of cooling flows from Xray data. The results for the present sample of clusters indicate ages of between 2.5 and 7 Gyr. If the ages of cooling flows are primarily set by subcluster merger events, then our results suggest that in the largest clusters, mergers with subclusters with masses of similar to 30 per cent of the final cluster mass are likely to disrupt cooling flows. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Wollongong, Dept Engn Phys, Wollongong, NSW 2522, Australia. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Allen, SW (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. NR 94 TC 88 Z9 89 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 11 PY 2001 VL 322 IS 3 BP 589 EP 613 DI 10.1046/j.1365-8711.2001.04135.x PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 422NZ UT WOS:000168126300014 ER PT J AU Hussain, GAJ Jardine, M Collier Cameron, A AF Hussain, GAJ Jardine, M Collier Cameron, A TI Mapping potential fields on the surfaces of rapidly rotating stars SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE polarization; stars : activity; stars : imaging; stars : late-type; stars : magnetic fields ID ACTIVITY CYCLE PERIOD; DIFFERENTIAL ROTATION; DOPPLER IMAGES; TIME EVOLUTION; MAGNETIC-FIELD; MAIN-SEQUENCE; AB DORADUS; COOL STARS; SOLAR-TYPE; BP STARS AB We present a technique that combines Zeeman Doppler imaging (ZDI) principles with a potential field mapping prescription in order to gain more information about the surface field topology of rapid rotators. This technique is an improvement on standard ZDI, which can sometimes suffer from the suppression of one vector component because of the effects of stellar inclination, poor phase coverage or lack of flux from dark areas on the surface. Defining a relationship between the different vector components allows information from one component to compensate for reduced information in another. We present simulations demonstrating the capability of this technique and discuss its prospects. C1 Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Hussain, GAJ (reprint author), Univ St Andrews, Sch Phys & Astron, North Haugh, St Andrews KY16 9SS, Fife, Scotland. NR 35 TC 20 Z9 20 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 11 PY 2001 VL 322 IS 3 BP 681 EP 688 DI 10.1046/j.1365-8711.2001.04149.x PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 422NZ UT WOS:000168126300021 ER PT J AU Rahbek, C Graves, GR AF Rahbek, C Graves, GR TI Multiscale assessment of patterns of avian species richness SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID LATITUDINAL GRADIENTS; GLOBAL PATTERNS; MOIST FORESTS; AREA RELATIONSHIP; SCALE DEPENDENCE; NULL MODEL; DIVERSITY; TREE; ENERGY; BIRDS AB The search for a common cause of species richness gradients has spawned more than 100 explanatory hypotheses in just the past two decades. Despite recent conceptual advances, further refinement of the most plausible models has been stifled by the difficulty of compiling high-resolution databases at continental scales. We used a database of the geographic ranges of 2,869 species of birds breeding in South America (nearly a third of the world's living avian species) to explore the influence of climate, quadrat area, ecosystem diversity, and topography on species richness gradients at 10 spatial scales (quadrat area, approximate to 12,300 to approximate to1,225,000 km(2)). Topography, precipitation, topography x latitude, ecosystem diversity, and cloud cover emerged as the most important predictors of regional variability of species richness in regression models incorporating 16 independent variables, although ranking of variables depended on spatial scale. Direct measures of ambient energy such as mean and maximum temperature were of ancillary importance. Species richness values for 1 degrees x 1 degrees latitude-longitude quadrats in the Andes (peaking at 845 species) were approximate to 30-250% greater than those recorded at equivalent latitudes in the central Amazon basin. These findings reflect the extraordinary abundance of species associated with humid montane regions at equatorial latitudes and the importance of orography in avian speciation. In a broader context, our data reinforce the hypothesis that terrestrial species richness from the equator to the poles is ultimately governed by a synergism between climate and coarse-scale topographic heterogeneity. C1 Univ Copenhagen, Museum Zool, DK-2100 Copenhagen O, Denmark. Natl Museum Nat Hist, Smithsonian Inst, Dept Vertebrate Zool, Washington, DC 20560 USA. RP Rahbek, C (reprint author), Univ Copenhagen, Museum Zool, Univ Parken 15, DK-2100 Copenhagen O, Denmark. RI Rahbek, Carsten/D-9372-2013; Rahbek, Carsten/L-1129-2013; publist, CMEC/C-3010-2012; publicationpage, cmec/B-4405-2017 NR 59 TC 487 Z9 518 U1 20 U2 171 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 APR 10 PY 2001 VL 98 IS 8 BP 4534 EP 4539 DI 10.1073/pnas.071034898 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 421HV UT WOS:000168059700050 PM 11296292 ER PT J AU Machado, CA Jousselin, E Kjellberg, F Compton, SG Herre, EA AF Machado, CA Jousselin, E Kjellberg, F Compton, SG Herre, EA TI Phylogenetic relationships, historical biogeography and character evolution of fig-pollinating wasps SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE fig wasp; pollination; biogeography; coevolution; Gondwana; mutualism ID FICUS-CARICA L; MAXIMUM-LIKELIHOOD; MITOCHONDRIAL-DNA; NUCLEOTIDE SUBSTITUTIONS; MOLECULAR PHYLOGENIES; MUTUALISM; SEQUENCES; AGAONIDAE; CHALCIDOIDEA; SPECIFICITY AB Nucleotide sequences from the cytochrome oxidase I (COI) gene were used to reconstruct phylogenetic relationships among 15 genera of fig-pollinating wasps. We present evidence supporting broad-level co-cladogenesis with respect to most but not all of the corresponding groups of figs. Using fossil evidence for calibrating a molecular clock for these data, we estimated the origin of the fig-wasp mutualism to have occurred ca. 90 million years ago. The estimated divergence times among the pollinator genera and their current geographical distributions corresponded well with several features of the break-up of the southern continents during the Late Cretaceous period. We then explored the evolutionary trajectories of two characteristics that hold profound consequences for both partners in the mutualism: the breeding system of the host (monoecious or dioecious) and pollination behaviour of the wasp (passive or active). The fig-wasp mutualism exhibits extraordinarily long-term evolutionary stability despite clearly identifiable conflicts of interest between the interactors, which are reflected by the very distinct variations found on the basic mutualistic theme. C1 Smithsonian Trop Res Inst, Balboa, Panama. CNRS, CEFE, F-34293 Montpellier 5, France. Univ Leeds, Sch Biol, Ctr Ecol & Evolut, Leeds LS2 9JT, W Yorkshire, England. RP Machado, CA (reprint author), Rutgers State Univ, Nelson Biol Labs, Dept Genet, 604 Allison Rd, Piscataway, NJ 08854 USA. EM machado@mbcl.rutgers.edu RI Machado, Carlos/B-8855-2009 OI Machado, Carlos/0000-0003-1546-7415 NR 86 TC 145 Z9 166 U1 7 U2 50 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8452 EI 1471-2954 J9 P ROY SOC B-BIOL SCI JI Proc. R. Soc. B-Biol. Sci. PD APR 7 PY 2001 VL 268 IS 1468 BP 685 EP 694 PG 10 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA 422DU UT WOS:000168103900003 PM 11321056 ER PT J AU Kress, WJ DePriest, P AF Kress, WJ DePriest, P TI What's in a PhyloCode name? SO SCIENCE LA English DT Letter C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol Bot, Washington, DC 20560 USA. RP Kress, WJ (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol Bot, Washington, DC 20560 USA. RI DePriest, Paula/K-6633-2015 NR 0 TC 0 Z9 1 U1 0 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 6 PY 2001 VL 292 IS 5514 BP 52 EP 52 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 420FU UT WOS:000167995200022 PM 11294213 ER PT J AU Schulze, A AF Schulze, A TI Ultrastructure of opisthosomal chaetae in Vestimentifera (Pogonophora, Obturata) and implications for phylogeny SO ACTA ZOOLOGICA LA English DT Article DE chaetae; setae; Pogonophora; Monilifera; Vestimentifera; Polychaeta; ultrastructure ID SOUTHWEST PACIFIC-OCEAN; ELONGATION FACTOR-1-ALPHA; ANNELID PHYLOGENY; HYDROTHERMAL VENT; HOOKED SETAE; TUBE WORMS; POLYCHAETA; POSITION; PERVIATA; GUT AB The posterior segmented body region of Vestimentifera bears rows of uncini that function to anchor the animal within its tube. SEM studies of five vestimentiferan species reveal intraspecific and interspecific variation in the number of chaetigerous segments and the arrangement of uncini within a given segment. The portion of an uncinus that extends beyond the epidermis comprises two opposing groups of teeth that probably correspond to the capitium and subrostral process of polychaete uncini, and a distinct protuberance between them, interpreted as a rostrum. In Ridgeia piscesae, the uncini are formed by chaetal follicles, consisting of a chaetoblast, a follicle cell and an epidermis cell. The chaetal shaft is elongate and composed of up to 40 hollow cylinders that are invaded at their base by microvilli from the apical part of the chaetoblast. Opisthosomal chaetae in perviate Pogonophora are usually restricted to four per segment and are of a rod-shaped type. It is hypothesized that the rod-shaped chaetae represent reduced hooked chaetae probably derived from a condition such as found in Monilifera. Uncini of Pogonophora, Sabellida,Terebellida and Oweniida are considered homologous but details of chaetal design may be due to functional adaptations and thus do not represent reliable characters for phylogenetic studies on higher taxonomic levels than genera or potentially families. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RP Schulze, A (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. RI Schulze, Anja/I-4215-2012 NR 40 TC 14 Z9 16 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0001-7272 J9 ACTA ZOOL-STOCKHOLM JI Acta Zool. PD APR PY 2001 VL 82 IS 2 BP 127 EP 135 DI 10.1046/j.1463-6395.2001.00074.x PG 9 WC Zoology SC Zoology GA 425AN UT WOS:000168266300004 ER PT J AU Helgen, KM Wilson, DE AF Helgen, KM Wilson, DE TI Additional material of the enigmatic golden mole Cryptochloris zyli, with notes on the genus Cryptochloris (Mammalia : Chrysochloridae) SO AFRICAN ZOOLOGY LA English DT Article DE Chrysochloridae; systematics; South Africa AB Van Zyl's golden mole (Cryptochloris zyli) is a distinctive but little-known species from the northwestern Cape Province of South Africa. Many authors have mentioned that it is known only by the holotype. Two other specimens are now known to exist; one was discovered in the Museum of Comparative Zoology at Harvard University, and the other, which has been mentioned in publication but overlooked, is in the Natural History Museum in London. Differentiation of C. zyli from sympatric chrysochlorids, and from its congener C, wintoni, are discussed. C1 Harvard Univ, Museum Comparat Zool, Dept Mammal, Cambridge, MA 02138 USA. Smithsonian Inst, Natl Museum Nat Hist, Div Mammals, Washington, DC 20560 USA. RP Helgen, KM (reprint author), Harvard Univ, Museum Comparat Zool, Dept Mammal, Cambridge, MA 02138 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU ZOOLOGICAL SOC SOUTHERN AFRICA PI PRETORIA PA AFRICAN ZOOLOGY CIRCULATION OFFICE, PO BOX 11663,, PRETORIA 0028, SOUTH AFRICA SN 1562-7020 J9 AFR ZOOL JI Afr. Zool. PD APR PY 2001 VL 36 IS 1 BP 110 EP 112 PG 3 WC Zoology SC Zoology GA 442ED UT WOS:000169271500014 ER PT J AU Kudoh, H Whigham, DF AF Kudoh, H Whigham, DF TI A genetic analysis of hydrologically dispersed seeds of Hibiscus moscheutos (Malvaceae) SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE allozyme variation; gene flow; Hibiscus moscheutos; hydrochory; Malvaceae; metapopulation approach; seed dispersal; wetland plants ID NATURAL-POPULATIONS; PLANT-COMMUNITIES; FLOW; DYNAMICS; DISTANCE; WETLAND; MARSH; HYDROCHORY; HISTORY; BANK AB The dispersal of floating seeds in wetland habitats should influence the genetic characteristics of plant metapopulations. we examined gene how of a hydrochorous wetland macrophyte, Hibiscus moscheutos L. (Malvaceae), by analyzing allozyme variation in current-year Boating-seed populations. The genetic composition of Rooting seeds was compared to the genetic composition of established populations of H. moscheutos that had been previously analyzed in the same areas. The F statistics demonstrated that genetic structuring among floating-seed populations was weak or absent, indicating that seeds from source populations were thoroughly mixed. Floating-seed populations had an excess of homozygotes. a different situation than had previously been found in established populations. The exchange of seeds was greatest among H. moscheutos populations that were adjacent to a tidal stream. We conclude that populations adjacent to the tidal streams are part of a metapopulation that serves as a reserve of genetic variation in the system. Although established populations of H. moscheutos that are not close to the tidal stream are relatively isolated genetically, we found evidence that they also contribute to the floating-seed population within the estuary. C1 Tokyo Metropolitan Univ, Grad Sch Sci, Dept Biol Sci, Hachioji, Tokyo 1920397, Japan. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Kudoh, H (reprint author), Tokyo Metropolitan Univ, Grad Sch Sci, Dept Biol Sci, Minami Osawa 1-1, Hachioji, Tokyo 1920397, Japan. OI Whigham, Dennis/0000-0003-1488-820X NR 54 TC 30 Z9 37 U1 0 U2 10 PU BOTANICAL SOC AMER INC PI COLUMBUS PA OHIO STATE UNIV-DEPT BOTANY, 1735 NEIL AVE, COLUMBUS, OH 43210 USA SN 0002-9122 J9 AM J BOT JI Am. J. Bot. PD APR PY 2001 VL 88 IS 4 BP 588 EP 593 DI 10.2307/2657057 PG 6 WC Plant Sciences SC Plant Sciences GA 422GY UT WOS:000168111200005 PM 11302843 ER PT J AU Ortner, DJ Butler, W Cafarella, J Milligan, L AF Ortner, DJ Butler, W Cafarella, J Milligan, L TI Evidence of probable scurvy in subadults from archeological sites in North America SO AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY LA English DT Article DE subadult scurvy; porotic lesions; hypertrophic lesions; North America; Native American nutrition AB The authors surveyed subadult human skeletons from Native American archeological sites in the United States for evidence of skeletal lesions associated with scurvy. Geographic regions surveyed include the Midatlantic area, the Southeast (Florida), the Southwest, and the Plains. The prevalence of probable subadult scurvy ranged from zero in the Plains samples to 38% in a small sample from Florida. These data indicate the likelihood that scurvy was a significant childhood disease in many Native American groups. Reasons for variation in prevalence remain speculative but include regional and seasonal variation in food types and abundance, cultural patterns of storage and utilization, periodic food shortages, and the relative importance of corn in the diet. These factors are part of a nutritional complex that is related to disease prevalence which can be studied through evidence seen in archeological human remains. (C) 2001 Wiley-Liss, Inc. C1 Smithsonian Inst, Museum Natl Hist Nat, Dept Anthropol, Washington, DC 20560 USA. Univ Bradford, Dept Archaeol Sci, Bradford BD7 1DP, W Yorkshire, England. RP Ortner, DJ (reprint author), Smithsonian Inst, Museum Natl Hist Nat, Dept Anthropol, Washington, DC 20560 USA. NR 19 TC 64 Z9 66 U1 2 U2 10 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0002-9483 J9 AM J PHYS ANTHROPOL JI Am. J. Phys. Anthropol. PD APR PY 2001 VL 114 IS 4 BP 343 EP 351 DI 10.1002/ajpa.1046 PG 9 WC Anthropology; Evolutionary Biology SC Anthropology; Evolutionary Biology GA 418NP UT WOS:000167898500006 PM 11275963 ER PT J AU Mochejska, BJ Kaluzny, J Stanek, KZ Sasselov, DD Szentgyorgyi, AH AF Mochejska, BJ Kaluzny, J Stanek, KZ Sasselov, DD Szentgyorgyi, AH TI Direct distances to nearby galaxies using detached eclipsing binaries and Cepheids. VII. Additional variables in the field M33A discovered with image subtraction SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : eclipsing; Cepheids; distance scale; galaxies : individual (M33); stars : variables : other ID LARGE-MAGELLANIC-CLOUD; STARS; MODE; M31; IV AB DIRECT is a project to directly obtain the distances to two Local Group galaxies, M31 and M33, which occupy a crucial position near the bottom of the cosmological distance ladder. As the first step of the DIRECT project, we have searched for detached eclipsing binaries (DEBs) and new Cepheids in the M31 and M33 galaxies with 1 m class telescopes. In this paper, we present a catalog of variable stars discovered in the data from the follow-up observations of the DEB system D33J013346.2+304439.9 in field M33A (alpha = 23.degrees 55, delta = 30.degrees 72; J2000.0), collected with the Kitt Peak National Observatory's 2.1 m telescope. In our search covering an area of 108 arcmin(2), we have found 434 variable stars : 63 eclipsing binaries, 305 Cepheids, and 66 other periodic, possible long-period, or nonperiodic variables. Of these variables, 280 are newly discovered, mainly short-period and/or faint Cepheids. Their light curves were extracted using the ISIS image subtraction package. For 85% of the variables, we present light curves in standard V and B magnitudes, with the remaining 15% expressed in units of differential flux. We have discovered a population of first-overtone Cepheid candidates, and for eight of them we present strong arguments in favor of this interpretation. We also report on the detection of a nonlinearity in the KPNO T2KA and T1KA cameras. The catalog of variables, as well as their photometry (similar to7.8 x 10(4) BV measurements) and finding charts, is available electronically via anonymous ftp and the World Wide Web. The complete set of the CCD frames is available upon request. C1 N Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mochejska, BJ (reprint author), N Copernicus Astron Ctr, Bartycka 18, PL-00716 Warsaw, Poland. NR 33 TC 35 Z9 35 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 2001 VL 121 IS 4 BP 2032 EP 2052 DI 10.1086/319970 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420UA UT WOS:000168022600018 ER PT J AU Adams, JD Stauffer, JR Monet, DG Skrutskie, MF Beichman, CA AF Adams, JD Stauffer, JR Monet, DG Skrutskie, MF Beichman, CA TI The mass and structure of the Pleiades star cluster from 2MASS SO ASTRONOMICAL JOURNAL LA English DT Article DE astrometry; celestial mechanics; open clusters and associations : individual (Pleiades); stars : low-mass, brown dwarfs ID N-BODY SIMULATIONS; PROPER-MOTION MEMBERSHIP; SOLAR-TYPE STARS; BROWN DWARFS; UNEQUAL MASSES; FAINT MEMBERS; EVOLUTION; SEARCH; FIELD; PROBABILITIES AB We present the results of a large-scale search for new members of the Pleiades star cluster using 2MASS near-infrared photometry and proper motions derived from POSS plates digitized by the USNO PMM program. The search extends to a 10 degrees radius around the cluster, well beyond the presumed tidal radius, to a limiting magnitude of R similar to 20, corresponding to similar to0.07 M-. at the distance and age of the Pleiades. Multiobject spectroscopy for 528 candidates verifies that the search was extremely effective at detecting cluster stars in the 1-0.1 M-. mass range using the distribution of H alpha emission strengths as an estimate of sample contamination by field stars. When combined with previously identified, higher mass stars, this search provides a sensitive measurement of the stellar mass function and dynamical structure of the Pleiades. The degree of tidal elongation of the halo agrees well with current N-body simulation results. Tidal truncation affects masses below similar to1 M-.. The cluster contains a total mass similar to 800 M-.. Evidence for a flatter mass function in the core than in the halo indicates the depletion of stars in the core with mass less than similar to0.5 M-., relative to stars with mass similar to1-0.5 M-., and implies a preference for very low-mass objects to populate the halo or escape. The overall mass function is best fitted with a lognormal form that becomes flat at similar to0.1 M-.. Whether sufficient dynamical evaporation has occurred to detectably flatten the initial mass function, via preferential escape of very low-mass stars and brown dwarfs, is undetermined, pending better membership information for stars at large radial distances. C1 Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Boston Univ, Inst Astrophys Res, 725 Commonwealth Ave, Boston, MA 02215 USA. EM jdadams@bu.edu; stauffer@ipac.caltech.edu; dgm@nofs.navy.mil; skrutski@astro.umass.edu; chas@pop.jpl.nasa.gov NR 73 TC 50 Z9 53 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD APR PY 2001 VL 121 IS 4 BP 2053 EP 2064 DI 10.1086/319965 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420UA UT WOS:000168022600019 ER PT J AU Haisch, KE Lada, EA Lada, CJ AF Haisch, KE Lada, EA Lada, CJ TI Circumstellar disks in the IC 348 cluster SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; open clusters and associations : individual (IC 348); stars : formation ID YOUNG STELLAR OBJECTS; MAIN-SEQUENCE STARS; LOW-MASS STARS; T-TAURI STARS; IC 348; MOLECULAR CLOUD; INTRINSIC COLORS; IMAGING SURVEY; PHOTOMETRY; SPECTROSCOPY AB We report the results of the first sensitive L-band (3.4 mum) imaging survey of the young IC 348 cluster in Perseus. In conjunction with previously acquired JHK (1.25, 1.65, and 2.2 mum) observations, we use L-band data to obtain a census of the circumstellar disk population to m(K) = m(L) less than or equal to 120 in the central similar to 110 arcmin(2) region of the cluster. An analysis of the JHKL colors of 107 sources indicates that 65% +/- 8% of the cluster membership possesses (inner) circumstellar disks. This fraction is lower than those (86% +/- 8% and 80% +/- 7%) obtained from similar JHKL surveys of the younger NGC 2024 and Trapezium clusters, suggesting that the disk fraction in clusters decreases with cluster age. Sources with circumstellar disks in IC 348 have a median age of 0.9 Myr, while the diskless sources have a median age of 1.4 Myr, for a cluster distance of 320 pc. Although the difference in the median ages between the two populations is only marginally significant, our results suggest that over a timescale of similar to2-3 Myr more than a third of the disks in the IC 348 cluster disappear. Moreover, we find that at a very high confidence level the disk fraction is a function of spectral type. All stars earlier than G appear diskless, while stars with spectral types G and later have a disk fraction ranging between 50%-67%, with the latest-type stars having the higher disk fraction. This suggests that the disks around stars with spectral types G and earlier have evolved more rapidly than those with later spectral types. The L-band disk fraction for sources with similar ages in both IC 348 and Taurus is the same within the errors, suggesting that at least in clusters with no O stars the disk lifetime is independent of environment. C1 Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Haisch, KE (reprint author), Univ Florida, Dept Astron, 211 SSRB, Gainesville, FL 32611 USA. NR 45 TC 112 Z9 112 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 2001 VL 121 IS 4 BP 2065 EP 2074 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420UA UT WOS:000168022600020 ER PT J AU Torres, G AF Torres, G TI The change in the inclination angle of the noneclipsing binary ss lacertae: Future eclipses SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : eclipsing; binaries : spectroscopic; stars : fundamental parameters; stars : individual (SS Lacertae) ID PROGRAM; STAR AB Eclipses in the 14.4 day-period double-lined binary SS Lac were observed photographically and visually early in the twentieth century but stopped some 50 or 60 yr ago. This has been explained by the presence of a distant third star in the system, which has now been detected spectroscopically, with a period of 679 days. The plane of the orbit of the binary is changing relative to the line of sight in response to perturbations from this third object. A recent analysis by Milone et al. of all photometric material available for the system, including a remeasurement of original Harvard plates, has confirmed earlier reports of changes in the depth of the eclipses as a function of time, which are due to the third star. In this paper we discuss our detailed analysis of the eclipse amplitude measurements and extract from them information on the change in the inclination angle of the binary over the last century. Our use of a much improved ephemeris for the system by Torres & Stefanik was found to be crucial, and it prompted us to redetermine all the amplitudes from the historical data at our disposal, including the Harvard material used by Milone et al. Systematically lower measurements on the branches of the minima were properly accounted for, and we made use of both a linear approximation to the time variation of the inclination angle and a more realistic model based on the theory of three-body interactions ("regression of the nodes" effect). The nodal cycle is found to be similar to 600 yr, within which two eclipse "seasons" occur, each lasting about 100 yr. The noneclipsing status of the system is expected to continue until the beginning of the twenty-third century. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Torres, G (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 27 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 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 2001 VL 121 IS 4 BP 2227 EP 2238 DI 10.1086/319942 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420UA UT WOS:000168022600034 ER PT J AU Maraston, C Kissler-Patig, M Brodie, JP Barmby, P Huchra, JP AF Maraston, C Kissler-Patig, M Brodie, JP Barmby, P Huchra, JP TI The AGB phase-transition outside the local group: K-band observations of young star clusters in NGC 7252 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : star clusters : stellar content : interactions; stars : AGB and post-AGB; stars : evolution ID ASYMPTOTIC GIANT BRANCH; EARLY-TYPE GALAXIES; REMNANT NGC 7252; STELLAR POPULATIONS; GLOBULAR-CLUSTERS; ELLIPTIC GALAXIES; EVOLUTIONARY SYNTHESIS; KECK SPECTROSCOPY; MAGELLANIC CLOUDS; SYSTEMS AB We have extended the study of the young star clusters observed in the merger remnant galaxy NGC 7252 by obtaining K band photometry for these clusters. Our K band data significantly complement the optical photometry and spectroscopy in the literature: K band data are fundamental to study the Asymptotic Giant Branch (AGB) population of these clusters, since the AGE phase transition (occuring between the age of similar to 200 Myr and similar to1 Gyr) causes abrupt changes in the near-infrared luminosity of the clusters while producing only small changes in the optical. Therefore, the e.g. V-K colour is ideal to study this evolutionary phase of stellar populations. For the present analysis we present models for Simple Stellar Populations which include the contribution of the AGE stellar phase, calibrated with the young and intermediate age star clusters of the Magellanic Clouds. The comparison with the colour distribution of the NGC 7252 star clusters shows that they are indeed intermediate age clusters undergoing the AGE phase transition. The AGE phase transition is observed for the first time outside the Local Group. Most of the studied clusters span the very narrow age range 300-500 Myr, and likely base metallicities 0.5-1 Z(circle dot). A very important exception is the cluster W32, which has already completed its AGE epoch, its colours being consistent with an age of similar to1-2 Gyr. This impacts on the duration of the merger-induced starburst. The strengths of the magnesium and iron lines in the spectrum of the best observed cluster W3, and in the spectrum of the diffuse central light of NGC 7252, do not show an overabundance in alpha -elements, in contrast to the bulk stellar population of elliptical galaxies. C1 Univ Munich, Univ Sternwarte, D-81679 Munich, Germany. European So Observ, D-85748 Garching, Germany. Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Munich, Univ Sternwarte, Scheinerstr 1, D-81679 Munich, Germany. EM maraston@usm.uni-muenchen.de; mkissler@eso.org; brodie@ucolick.org; pbarmby@cfa.harvard.edu; huchra@cfa.harvard.edu RI Barmby, Pauline/I-7194-2016 OI Barmby, Pauline/0000-0003-2767-0090 NR 61 TC 54 Z9 54 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2001 VL 370 IS 1 BP 176 EP 193 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 432FW UT WOS:000168682400024 ER PT J AU Santos-Lleo, M Clavel, J Schulz, B Altieri, B Barr, P Alloin, D Berlind, P Bertram, R Crenshaw, DM Edelson, RA Giveon, U Horne, K Huchra, JP Kaspi, S Kriss, GA Krolik, JH Malkan, MA Malkov, YF Netzer, H O'Brien, PT Peterson, BM Pogge, RW Pronik, VI Qian, BC Reichert, GA Rodriguez-Pascual, PM Sergeev, SG Tao, J Tokarz, S Wagner, RM Wamsteker, W Wilkes, BJ AF Santos-Lleo, M Clavel, J Schulz, B Altieri, B Barr, P Alloin, D Berlind, P Bertram, R Crenshaw, DM Edelson, RA Giveon, U Horne, K Huchra, JP Kaspi, S Kriss, GA Krolik, JH Malkan, MA Malkov, YF Netzer, H O'Brien, PT Peterson, BM Pogge, RW Pronik, VI Qian, BC Reichert, GA Rodriguez-Pascual, PM Sergeev, SG Tao, J Tokarz, S Wagner, RM Wamsteker, W Wilkes, BJ TI Monitoring of the optical and 2.5-11.7 mu m spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk 279 with ISO SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : individual : Mrk 279; galaxies : nuclei; galaxies : Seyfert; infrared : galaxies ID ACTIVE GALACTIC NUCLEI; BROAD-LINE REGION; ADAPTIVE OPTICS; X-RAY; INFRARED VARIABILITY; HOMOGENEOUS SAMPLE; HOT DUST; EMISSION; QUASARS; SPECTROSCOPY AB Mid-infrared images of the Seyfert 1 galaxy Mrk 279 obtained with the ISO satellite are presented together with the results of a one-year monitoring campaign of the 2.5-11.7 mum spectrum. Contemporaneous optical photometric and spectrophotometric observations are also presented. The galaxy appears as a point-like source at the resolution of the ISOCAM instrument (4-5 "). The 2.5-11.7 mum average spectrum of the nucleus in Mrk 279 shows a strong power law continuum with alpha = -0.80 +/- 0.05 (F nu proportional to nu (alpha)) and weak PAK emission features. The Mrk 279 spectral energy distribution shows a mid-IR bump, which extends from 2 to 15-20 mum The mid-IR bump is consistent with thermal emission from dust grains at a distance of greater than or similar to 100 It-d. No significant variations of the mid-IR flux have been detected during our observing campaign, consistent with the relatively low amplitude (similar to 10% rms) of the optical variability during the campaign. The time delay for H beta line emission in response to the optical continuum variations is tau = 16.7(-5.6)(+5.3), days, consistent with previous measurements. C1 ESA, Dept Space Sci, Div Astrophys, Sci Operat Ctr XMM, E-28080 Madrid, Spain. ESA, Dept Space Sci, Div Astrophys, Sci Operat Ctr ISO, E-28080 Madrid, Spain. European Space Agcy, Estec, Dept Space Sci, Astrophys Div,Integral Sci Operat Ctr, NL-2200 AG Noordwijk, Netherlands. European So Observ, Santiago 19, Chile. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Comp Sci Corp, Greenbelt, MD 20771 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90024 USA. Crimean Astrophys Observ, UA-334413 Nauchnyi, Ukraine. Shanghai Astron Observ, Shanghai 200030, Peoples R China. NASA, Goddard Space Flight Ctr, Space Sci Data Operat Off, Raytheon ITSS, Greenbelt, MD 20771 USA. Univ Europea Madrid, Dept Fis, Madrid 28670, Spain. ESA, IUE Observ, Madrid 28080, Spain. RP ESA, Dept Space Sci, Div Astrophys, Sci Operat Ctr XMM, POB 50727, E-28080 Madrid, Spain. EM msantos@xmm.vilspa.esa.es OI Wilkes, Belinda/0000-0003-1809-2364; Altieri, Bruno/0000-0003-3936-0284 NR 47 TC 24 Z9 24 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2001 VL 369 IS 1 BP 57 EP 64 DI 10.1051/0004-6361:20010103 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 423UH UT WOS:000168195800009 ER PT J AU Nevalainen, J Kaastra, J Parmar, AN Markevitch, M Oosterbroek, T Colafrancesco, S Mazzotta, P AF Nevalainen, J Kaastra, J Parmar, AN Markevitch, M Oosterbroek, T Colafrancesco, S Mazzotta, P TI Temperature and total mass profiles of the A3571 cluster of galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE cosmology : observations; dark matter; X-rays : clusters of galaxies ID BEPPOSAX OBSERVATION; COOLING FLOWS; DARK-MATTER; RAY; ABELL-2256; ENERGY; ASCA AB We present BeppoSAX results of a spatially resolved spectral analysis of A3571, a relaxed nearby cluster of galaxies. In the central 2 ' (130 h(50)(-1) kpc) radius the metal abundance is 0.49 +/- 0.08 solar and the absorption (1.13 +/- 0.28) 10(21) atom cm(-2), whereas elsewhere within an 8 ' (520 h(50)(-1) kpc) radius the abundance is 0.32 +/- 0.05 solar and she absorption consistent with the galactic value of 4.4 10(20) atom cm(-2). The significant central metal abundance enhancement is consistent with the supernova enrichment scenario. The excess absorption may be attributed to the cooling flow, whose mass flow rate is 80 +/- 40 M-circle dot yr(-1) from our spectral fit. The BeppoSAX and ASCA radial temperature profiles agree over the entire overlapping radial range r < 25 = 1.6 h(50)(-1) Mpc. The combined BeppoSAX and ASCA temperature profile exhibits a constant value out to a radius of similar to 10 ' (650 h(50)(-1) kpc) and a significant decrease (T proportional to r(-0.55), corresponding to gamma = 1.28) at larger radii. These temperature data are used to derive the total mass profile. The best fit NFW dark matter density model results in a temperature profile that is not convectively stable, but the model is acceptable within the uncertainties of the data. The temperature profile is acceptably modeled with a "core" model for the dark matter density, consisting of a core radius with a constant slope at larger radii. With this model the total mass and for mal 90% confidence errors within the virial radius r(178) (2.5 h(50)(-1) Mpc) are 9.1(-1.5)(+3.6) 10(14) h(50)(-1) M-circle dot, by a factor of 1.4 smaller than the isothermal value. The gas mass fraction increases with radius, reaching f(gas) (r(178)) = 0.26(-0.10)(+0.05) x h(50)(-3/2). Assuming that the measured gas mass fraction is the lower limit to the primordial baryonic fraction gives Omega (m) < 0.4. at 90% confidence. C1 European Space Agcy, Estec, Dept Space Sci, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron Roma, I-00040 Monte Porzio Catone, Italy. RP Nevalainen, J (reprint author), European Space Agcy, Estec, Dept Space Sci, Div Astrophys, Postbus 299, NL-2200 AG Noordwijk, Netherlands. EM jnevalai@astro.estec.esa.nl RI Mazzotta, Pasquale/B-1225-2016; OI Mazzotta, Pasquale/0000-0002-5411-1748; Parmar, Arvind/0000-0002-3307-6517 NR 45 TC 12 Z9 12 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2001 VL 369 IS 2 BP 459 EP 466 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 426GZ UT WOS:000168342600013 ER PT J AU van den Ancker, ME Meeus, G Cami, J Waters, LBFM Waelkens, C AF van den Ancker, ME Meeus, G Cami, J Waters, LBFM Waelkens, C TI The composition of circumstellar gas and dust in 51 Oph SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE circumstellar matter; stars : emission-line; stars : evolution; stars : 51 Oph; infrared : stars ID WAVELENGTH SPECTROMETER; BETA-PICTORIS; AE/BE STARS; SPECTROSCOPY; SOUTHERN; SYSTEM; 51-OPHIUCHI; VELOCITIES; ATMOSPHERE; EMISSION AB We analyze ISO archive data of the nearby bright emission-line star 51 Oph, previously classified as a proto-planetary system similar to P Pie. The infrared spectrum reveals the presence of gas-phase emission bands of hot (similar to 850 K) CO, CO(2), H(2)O and NO. In addition to this, partially crystalline silicate dust is present. The solid-state bands and the energy distribution are indicative of dust that has: formed recently, rather than of debris dust. The presence of hot molecular gas and the composition of the circumstellar dust are highly unusual for a young star and are reminiscent of what is found around evolved (AGB) stars, although we exclude the possibility of 51 Oph belonging to this group. We suggest several explanations for the nature of 51 Oph, including a recent episode of mass loss from a Be star, and the recent destruction of a planet-sized body around a young star. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Katholieke Univ Leuven, Inst Sterrenkunde, B-3001 Heverlee, Belgium. SRON, NL-9700 AV Groningen, Netherlands. RP van den Ancker, ME (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 42, Cambridge, MA 02138 USA. EM mvandenancker@cfa.harvard.edu NR 35 TC 26 Z9 26 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2001 VL 369 IS 2 BP L17 EP L21 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 426GZ UT WOS:000168342600003 ER PT J AU Puchnarewicz, EM Mason, KO Siemiginowska, A Fruscione, A Comastri, A Fiore, F Cagnoni, I AF Puchnarewicz, EM Mason, KO Siemiginowska, A Fruscione, A Comastri, A Fiore, F Cagnoni, I TI Constraining the black hole mass and accretion rate in the narrow-line Seyfert 1 galaxy RE J1034+396 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies : active; galaxies : individual (RE J1034+396); galaxies : nuclei; galaxies : Seyfert; X-rays : galaxies ID RAY ASTRONOMY SATELLITE; ENERGY CONCENTRATOR SPECTROMETER; EXTREME-ULTRAVIOLET EXPLORER; BIG BLUE BUMP; ON-BOARD; VARIABILITY; QUASARS; SPECTRA; MODELS; DISKS AB We present a comprehensive study of the spectrum of the narrow-line Seyfert 1 (NLS1) galaxy RE J1034+396, summarizing the information obtained from the optical to X-rays with observations from the William Herschel 4.2 m Telescope, the Hubble Space Telescope, the Extreme Ultraviolet Explorer, ROSAT, ASCA, and BeppoSAX. The BeppoSAX spectra reveal a soft component which is well represented by two blackbodies with kT(eff) = 60 and 160 eV, mimicking that expected from a hot, optically thick accretion disk around a low-mass black hole. This is borne out by our modeling of the optical-to- X-ray nuclear continuum, which constrains the physical parameters of a NLS1 for the first time. The models demonstrate that RE J1034+396 is likely to be a system with a nearly edge-on accretion disk (60 degrees -75 degrees from the disk axis), accreting at nearly Eddington rates (0.3-07L(Edd)) onto a low-mass black hole (M-bh similar to 2-10 x 10(6) M.). This is consistent with the hypothesis that NLS1s are Seyfert-scale analogies of galactic black hole candidates. The unusually high temperature of the big blue bump reveals a flat power-law-like continuum in the optical/UV which is consistent with an extrapolation to the hard X-ray power law, and which we speculate may be similar to the continuum component observed in BL Lac objects in their quiescent periods. From the BeppoSAX and ASCA data, we find that the slope of the hard X-ray power law depends very much on the form of the soft component which is assumed. For our best-fitting models, it lies somewhere between alpha = 0.7 and 1.3 and thus may not be significantly softer than active galactic nuclei in general. C1 UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron Bologna, I-40127 Bologna, Italy. Osserv Astron Roma, I-00040 Monte Porzio Catone, Rm, Italy. Scuola Int Super Studi Avanzati, I-34014 Trieste, Italy. RP UCL, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. EM emp@mssl.ucl.ac.uk; kom@mssl.ucl.ac.uk; aneta@head-cfa.harvard.edu; antonell@head-cfa.harvard.edu; comastri@astbo3.bo.astro.it; fiore@quasar.mporzio.astro.it; ilaria@head-cfa.harvard.edu RI Comastri, Andrea/O-9543-2015; OI Comastri, Andrea/0000-0003-3451-9970; Fiore, Fabrizio/0000-0002-4031-4157 NR 35 TC 38 Z9 38 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 APR 1 PY 2001 VL 550 IS 2 BP 644 EP 654 DI 10.1086/319775 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FM UT WOS:000167993900012 ER PT J AU Muzerolle, J Calvet, N Hartmann, L AF Muzerolle, J Calvet, N Hartmann, L TI Emission-line diagnostics of T tauri magnetospheric accretion. II. Improved model tests and insights into accretion physics SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; radiative transfer; stars : formation; stars : pre-main-sequence ID MAGNETIC NEUTRON STARS; YOUNG STELLAR OBJECTS; DISK ACCRETION; BP-TAURI; VARIABILITY; FLOWS; EVOLUTION; PROFILES; ROTATION AB We present new radiative transfer models of magnetospheric accretion in T Tauri stars. Hydrogen and Na I line profiles were calculated, including line damping and continuum opacity for a grid of models spanning a large range of infall rates, magnetospheric geometries, and gas temperatures. We also calculated models for rotating magnetospheres and show that for typical T Tauri rotation rates, the line profiles are not significantly affected. We show that line-damping wings can produce significant high-velocity emission at Ha, and to a lesser extent in higher Balmer lines, in much better agreement with observations than previous models. We present comparisons to specific objects spanning a wide range of accretion activity and find that in most cases the models successfully reproduce the observed emission profile features. Blueshifted absorption components cannot be explained without including a wind outside of the magnetosphere, and true P Cygni Balmer line profiles in the few objects with extreme accretion activity indicate both absorption and emission from a wind. We constrain the range of gas temperatures required to explain observational diagnostics like profile shapes, line ratios, and continuum emission. The exact heating mechanism remains unclear but is probably linked to the accretion process itself. In order to explain observed correlations between line emission and accretion luminosity, we find that the size of the emitting region must be correlated with the accretion rate. We suggest that such a correlation may manifest itself in reality via nonaxisymmetric accretion, where the number and/or width of discrete funnel flows increase with increasing accretion rate, a scenario also indicated by accretion shock models. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Ctr Invest Astron, Merida 5101A, Venezuela. RP Muzerolle, J (reprint author), Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA. NR 47 TC 256 Z9 256 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 APR 1 PY 2001 VL 550 IS 2 BP 944 EP 961 DI 10.1086/319779 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FM UT WOS:000167993900038 ER PT J AU Belczynski, K Kalogera, V AF Belczynski, K Kalogera, V TI A new formation channel for double neutron stars without recycling: Implications for gravitational wave detection SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; gravitational waves; stars : evolution; stars : formation; star : neutron ID PRESUPERNOVA EVOLUTION; HELIUM STAR; BINARIES; MASS; SYSTEMS; SUPERNOVAE; ACCRETION; PULSARS; MODELS; KICKS AB We report on a new evolutionary path leading to the formation of close double neutron stars (NSs), with the unique characteristic that none of the two NSs ever had the chance to be recycled by accretion. The existence of this channel stems from the evolution of helium-rich stars (cores of massive NS progenitors), which has been neglected in most previous studies of double compact object formation. We find that these nonrecycled NS-NS binaries are formed from bare carbon-oxygen cores in tight orbits, with formation rates comparable to or maybe even higher than those of recycled NS-NS binaries. On the other hand, their detection probability as binary pulsars is greatly reduced (by similar to 10(3)) relative to recycled pulsars because of their short lifetimes. We conclude that, in the context of gravitational wave detection of NS-NS in-spiral events, this new type of binaries calls for an increase of the rate estimates derived from the observed NS-NS systems with recycled pulsars, typically by factors of 1.5-3 or even higher. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Nicolaus Copernicus Astron Ctr, PL-00716 Warsaw, Poland. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM kbelczynski@cfa.harvard.edu; vkalogera@cfa.harvard.edu NR 36 TC 51 Z9 51 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 APR 1 PY 2001 VL 550 IS 2 BP L183 EP L187 DI 10.1086/319641 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FN UT WOS:000167994000015 ER PT J AU Chartas, G Bautz, M Garmire, G Jones, C Schneider, DP AF Chartas, G Bautz, M Garmire, G Jones, C Schneider, DP TI Chandra observations of the gravitationally lensed system 2016+112 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : clusters : general; gravitational lensing; X-rays : galaxies ID DARK CLUSTER; REDSHIFT; GALAXY; IMAGE AB An observation of the gravitationally lensed system 2016 + 112 with the Chandra X-Ray Observatory has resolved a mystery regarding the proposed presence of a dark matter object in the lens plane of this system. The Chandra Advanced CCD Imaging Spectrometer observation has clearly detected the lensed images of 2016 + 112 with positions in good agreement with those reported in the optical and also detects 13 additional X-ray sources within a radius of 3'.5. Previous X-ray observations in the direction of 2016 + 112 with the ROSAT HRI and ASCA Solid-State Imaging Spectrometer have interpreted the X-ray data as arising from extended emission from a dark cluster. However, the present Chandra observation can account for all the X-ray emission as originating from the lensed images and additional point X-ray sources in the field. Thus, cluster parameters based on previous X-ray observations are unreliable. We place a 3 sigma upper limit on the 2-10 keV flux and luminosity of the cluster of 1.6 x 10(-14) ergs s(-1) cm(-2) and 1.7 x 10(44) ergs s(-1), respectively. We estimate an upper limit on the mass-to-light within a radius of 800 h(50)(-1) kpc of M/L-V < 190 h(50) (M/L-V)(). None of the additional point X-ray sources are associated with the galaxy cluster members recently detected in deep optical and IR observations. The lensed object is quite unusual, with reported narrow emission lines in the optical that suggest it may be a type 2 quasar. Our modeling of the X-ray spectrum of the lensed object implies that the column density of an intrinsic absorber must lie between 3 and 85 x 10(22) cm(-2) (3 sigma confidence level). The 2-10 keV luminosity of 22 85 # 10 the lensed object, corrected for the lens magnification effect and using the above range of intrinsic absorption, is from 3 x 10(43) to 1.4 x 10(44) erts s(-1). C1 Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Chartas, G (reprint author), Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA. NR 19 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 APR 1 PY 2001 VL 550 IS 2 BP L163 EP L167 DI 10.1086/319632 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FN UT WOS:000167994000011 ER PT J AU Jayawardhana, R Wolk, SJ Navascues, DBY AF Jayawardhana, R Wolk, SJ Navascues, DBY TI Protoplanetary disks in the nearest star-forming cloud: Mid-infrared imaging and optical spectroscopy of MBM 12 members SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; circumstellar matter; open clusters and associations : individual (MBM 12); planetary systems; stars : formation; stars : pre-main-sequence ID T-TAURI STARS; EMISSION; SEARCH AB The recent identification of several groups of young stars within 100 pc of the Sun has generated widespread interest. Given their proximity and possible age differences, these systems are ideally suited for detailed studies of star and planet formation. Here we report on the first investigation of protoplanetary disks in one such group, the high-latitude cloud MBM 12 at a distance of similar to 65 pc. We present mid-infrared observations of the eight candidate pre-main-sequence (PMS) members and the two main-sequence (MS) stars in the same line of sight, which may or may not be associated with the group. We have also derived H alpha and Li line widths from medium-resolution optical spectra. We report the discovery of significant mid-infrared excess from six PMS stars-LkH alpha 262, LkH alpha 263, LkH alpha 264, E02553 + 2018, RX J0258.3 + 1947, and S18-presumably due to optically thick circumstellar disks. Our flux measurements for the other two PMS stars and the two MS stars are consistent with photospheric emission, allowing us to rule out dusty inner disks. The disks we have found in MBM 12 represent the nearest known sample of very young protoplanetary systems and thus are prime targets for high-resolution imaging at infrared and millimeter wavelengths. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Autonoma Madrid, Dept Fis Teor, E-28049 Madrid, Spain. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jayawardhana, R (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Barrado Navascues, David/C-1439-2017; OI Barrado Navascues, David/0000-0002-5971-9242; Wolk, Scott/0000-0002-0826-9261 NR 20 TC 25 Z9 25 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 APR 1 PY 2001 VL 550 IS 2 BP L197 EP L200 DI 10.1086/319647 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FN UT WOS:000167994000018 ER PT J AU Kastner, JH Vrtilek, SD Soker, N AF Kastner, JH Vrtilek, SD Soker, N TI Discovery of extended X-ray emission from the planetary nebula NGC 7027 by the Chandra x-ray observatory SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary nebulae : individual (NGC 7027); stars : mass loss; stars : winds, outflows; X-rays : ISM ID PHOTODISSOCIATION REGION; CENTRAL STARS; NGC-7027; H-2 AB We report the discovery of X-ray emission from NGC 7027,a prototypical object for the study of the formation and evolution of planetary nebulae. Observations with the Advanced CCD Imaging Spectrometer (ACIS) aboard the Chandra X-Ray Observatory show that the X-ray emission from NGC 7027 is extended and is bipolar in morphology. The ACIS spectrum displays strong emission from highly ionized Ne and weaker emission features, which we attribute to O, Mg, and Si. Model fits to this spectrum suggest a characteristic temperature T-X similar to 3 x 10(6) K and an intrinsic (unabsorbed) X-ray luminosity of L-X similar to 1.3 x 10(32) ergs s(-1). The intranebular absorption of X-ray emission is highly nonuniform, but the modeling indicates an average column density N-H similar to 6 x 10(21) cm(-2), consistent with previous measurements of relatively large visual extinction within the nebula. We suggest that the X-ray emission from NGC 7027 is or was generated by a hitherto undetected fast wind from the central star of NGC 7027 or from a companion to this star. Chandra's detection of extended, high-temperature X-ray emission from BD +30 degrees 3639, NGC 6543, and now NGC 7027 suggests that such emission is a common feature of young planetary nebulae. C1 Rochester Inst Technol, Chester F Carlson Ctr Imaging Sci, Rochester, NY 14623 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Haifa, Dept Phys, IL-36006 Oranim, Tivon, Israel. RP Kastner, JH (reprint author), Rochester Inst Technol, Chester F Carlson Ctr Imaging Sci, 54 Lomb Mem Dr, Rochester, NY 14623 USA. NR 25 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 APR 1 PY 2001 VL 550 IS 2 BP L189 EP L192 DI 10.1086/319651 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FN UT WOS:000167994000016 ER PT J AU Macri, LM Sasselov, DD Stanek, KZ AF Macri, LM Sasselov, DD Stanek, KZ TI A Cepheid is no more: Hubble's variable 19 in M33 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cepheids; galaxies : individual (M33)evolution ID DETACHED ECLIPSING BINARIES; SPIRAL GALAXY M33; NEARBY GALAXIES; DIRECT DISTANCES; RADIAL-VELOCITY; STELLAR CONTENT; STARS; PHOTOMETRY AB We report on the remarkable evolution in the light curve of a variable star discovered by Hubble in M33 and classified by him as a Cepheid. Early in the 20th century, the variable, designated as V19, exhibited a 54.7 day period, an intensity-weighted mean B magnitude of 10.59 +/- 0.23 mag, and a B amplitude of 1.1 mag. Its position in the period-luminosity plane was consistent with the relation derived by Hubble from a total of 35 variables. Modern observations by the DIRECT project show a dramatic change in the properties of V19: its mean B magnitude has risen to 19.08 +/- 0.05 mag, and its B amplitude has decreased to less than 0.1 mag. V19 does not appear to be a classical (Population I) Cepheid variable at present, and its nature remains a mystery. It is not clear how frequent such objects are or how often they could be mistaken for classical Cepheids. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Macri, LM (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Macri, Lucas/0000-0002-1775-4859 NR 31 TC 10 Z9 10 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 APR 1 PY 2001 VL 550 IS 2 BP L159 EP L162 DI 10.1086/319637 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FN UT WOS:000167994000010 ER PT J AU White, M Hernquist, L Springel, V AF White, M Hernquist, L Springel, V TI The halo model and numerical simulations SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; large-scale structure of universe ID HYDRODYNAMICAL SIMULATIONS; SUPERNOVA FEEDBACK; GALAXY FORMATION; UNIVERSE; PROFILES; DENSITY; GAS AB Recently there has been a lot of attention focused on a virialized halo-based approach to understanding the properties of the matter and galaxy power spectrum. A key ingredient in this model is the number and distribution of galaxies within dark matter halos as a function of mass. This quantity has been predicted from semianalytic modeling and from fits to observational data. Here we present predictions for the occupation number and spatial distribution of subhalos based on a high-resolution hydrodynamical simulation including cooling, star formation, and feedback. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP White, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI White, Martin/I-3880-2015; OI White, Martin/0000-0001-9912-5070; Springel, Volker/0000-0001-5976-4599 NR 34 TC 37 Z9 37 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2001 VL 550 IS 2 BP L129 EP L132 DI 10.1086/319644 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FN UT WOS:000167994000003 ER PT J AU Witt, AN Smith, RK Dwek, E AF Witt, AN Smith, RK Dwek, E TI X-ray halos and large grains in the diffuse interstellar medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; ISM : abundances; scattering; X-rays : ISM ID IN-SITU MEASUREMENTS; SIZE DISTRIBUTION; OPTICAL-PROPERTIES; DUST PARTICLES; SCATTERING; POLARIZATION; GRAPHITE; CARBON; METEORITES; EVOLUTION AB Recent observations with dust detectors on board the interplanetary spacecrafts Ulysses and Galileo have recorded a substantial flux of large interstellar grains with radii between 0.25 and 2.0 mum entering the solar system from the local interstellar cloud. The most commonly used interstellar grain size distribution is characterized by an a(-3.5) power law in grain radii a and extends to a maximum grain radius of 0.25 mum. The extension of the interstellar grain size distribution to such large radii will have a major effect on the median grain size and on the amount of mass needed to be tied up in dust for a given visual optical depth. It is therefore important to investigate whether this population of larger dust particles prevails in the general interstellar medium or whether it is merely a local phenomenon. The presence of large interstellar grains can be inferred mainly from their effect on the intensity and radial profile of scattering halos around X-ray sources. In this Letter, we examine the grain size distribution that gives rise to the X-ray halo around Nova Cygni 1992. The results of our study confirm the need to extend the interstellar grain size distribution in the direction of this source to and possibly beyond 2 mum. The model that gives the best fit to the halo data is characterized by (1) a grain size distribution that follows an power law up to a(-3.)5 a 0.50 mum, followed by an a(-4.0) extension from 0.50 to 2.0 mum, and (2) silicate and graphite (carbon) dust-to-gas mass ratios of 0.0044 and 0.0022, respectively, consistent with solar abundance constraints. Additional observations of X-ray halos probing other spatial directions are badly needed to test the general validity of this result. C1 Univ Toledo, Ritter Astrophys Res Ctr, Toledo, OH 43606 USA. Harvard Smithsonian Ctr Astrophys, High Energy Astrophys Div, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Witt, AN (reprint author), Univ Toledo, Ritter Astrophys Res Ctr, 2801 W Bancroft St, Toledo, OH 43606 USA. OI Witt, Adolf/0000-0003-0760-4483 NR 39 TC 28 Z9 29 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 APR 1 PY 2001 VL 550 IS 2 BP L201 EP L205 DI 10.1086/319630 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420FN UT WOS:000167994000019 ER PT J AU Abu-Asab, MS Peterson, PM Shetler, SG Orli, SS AF Abu-Asab, MS Peterson, PM Shetler, SG Orli, SS TI Earlier plant flowering in spring as a response to global warming in the Washington, DC, area SO BIODIVERSITY AND CONSERVATION LA English DT Article DE first-flowering; global warming; minimum temperature; spring-flowering; Washington DC ID CLIMATE AB Evidence for global warming is inferred from spring advances in first-flowering in plants. The trend of average first-flowering times per year for the study group shows a significant advance of 2.4 days over a 30-year period. When 11 species that exhibit later first-flowering times are excluded from the data set, the remaining 89 show a significant advance of 4.5 days. Significant trends for earlier-flowering species range from -3.2 to -46 days, while those for later-flowering species range from +3.1 to +10.4 days. Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (T-min). C1 NCI, Sect Ultrastruct Pathol, Pathol Lab, Bethesda, MD 20892 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, Washington, DC 20560 USA. RP Abu-Asab, MS (reprint author), NCI, Sect Ultrastruct Pathol, Pathol Lab, Bethesda, MD 20892 USA. OI Abu-Asab, Mones/0000-0002-4047-1232 NR 10 TC 137 Z9 162 U1 5 U2 52 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0960-3115 J9 BIODIVERS CONSERV JI Biodivers. Conserv. PD APR PY 2001 VL 10 IS 4 BP 597 EP 612 DI 10.1023/A:1016667125469 PG 16 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 426AR UT WOS:000168327400008 ER PT J AU Pernet, B AF Pernet, B TI Escape hatches for the clonal offspring of serpulid polychaetes SO BIOLOGICAL BULLETIN LA English DT Article ID ASEXUAL REPRODUCTION AB Serpulid polychaetes in the genera Filograna and Salmacina reproduce asexually by releasing a single bud at a time from their posterior ends into their calcareous tubes. Here I show that buds of Salmacina amphidentata gain access to the exterior of these tubes via escape hatches built into the tubes by the parent worms. Each escape hatch consists of a hole in the tube blocked by a calcareous disc that is supported in place by an organic membrane. After buds detach from their parents, the calcareous discs are dislodged, and buds begin to form their own tubes from the resulting openings. Repeated bouts of asexual reproduction result in the formation of aggregations of branched tubes. A survey of Filograna and Salmacina spp. from the Atlantic, Indian, and Pacific oceans suggests that the formation of escape hatches for clonal offspring is common to many members of these genera. C1 Smithsonian Marine Stn Ft Pierce, Ft Pierce, FL 34949 USA. RP Pernet, B (reprint author), Oregon Inst Marine Biol, POB 5389,63466 Boat Basin Dr, Charleston, OR 97420 USA. OI Pernet, Bruno/0000-0002-6200-5654 NR 44 TC 15 Z9 16 U1 0 U2 2 PU MARINE BIOLOGICAL LABORATORY PI WOODS HOLE PA 7 MBL ST, WOODS HOLE, MA 02543 USA SN 0006-3185 J9 BIOL BULL JI Biol. Bull. PD APR PY 2001 VL 200 IS 2 BP 107 EP 117 DI 10.2307/1543304 PG 11 WC Biology; Marine & Freshwater Biology SC Life Sciences & Biomedicine - Other Topics; Marine & Freshwater Biology GA 427YT UT WOS:000168434900002 PM 11341572 ER PT J AU Basset, Y Aberlenc, HP Barrios, H Curletti, G Berenger, JM Vesco, JP Causse, P Haug, A Hennion, AS Lesobre, L Marques, F O'Meara, R AF Basset, Y Aberlenc, HP Barrios, H Curletti, G Berenger, JM Vesco, JP Causse, P Haug, A Hennion, AS Lesobre, L Marques, F O'Meara, R TI Stratification and diel activity of arthropods in a lowland rainforest in Gabon SO BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY LA English DT Article DE Agrilus; insect herbivores; species richness; understorey; upper canopy ID BORNEAN RAIN-FOREST; TROPICAL FOREST; CANOPY; DIVERSITY; TREES; COMMUNITIES; ABUNDANCE; SEASONALITY; SEEDLINGS; PATTERNS AB (The abundance, activity and species richness of arthropods, particularly of insect herbivores, were investigated in the upper canopy and understorey of a lowland rainforest at La Makande, Gabon. In total 14 161 arthropods were collected with beating, night interception and sticky traps, from six canopy sites, during the day and at night, from mid-January to mid-March 1999. The effects of stratum were most important, representing between 40 and 70% of the explained variance in arthropod distribution. Site effects represented between 20 and 40% of the variance and emphasized the need for replication of sampling among canopy sites. Time effects (diel activity) explained a much lower percentage of variance (6-9%). The density and abundance of many arthropod taxa and species were significantly higher in the upper canopy than in the understorey. Arthropod activity was also higher during the day than at night. In particular, insect herbivores were 2.5 times more abundant and twice as speciose in the upper canopy than in the understorey, a probable response to the greater and more diverse food resources in the former stratum. Faunal overlap between the upper canopy and understorey was low. The most dissimilar herbivore communities foraged in the understorey at night and the upper canopy during the day. Further, a taxonomic study of a species-rich genus of herbivore collected there (Agrilus, Coleoptera Buprestidae) confirmed that the fauna of the upper canopy was different, diverse and very poorly known in comparison to that of the understorey. Herbivore turnover between day and night was rather high in the upper canopy and no strong influx of insect herbivores from lower foliage to the upper canopy was detected at night. This suggests that insect herbivores of the upper canopy may be resident and well adapted to environmental conditions there. (C) 2001 The Linnean Society of London. C1 Smithsonian Trop Res Inst, Balboa, Ancon, Panama. Univ Panama, Programa Centroamer Maestria & Entomol, Balboa, Panama. CIRAD, F-34398 Montpellier 5, France. Museo Civ Storia Nat, I-10022 Carmagnola, TO, Italy. Clos Florette, F-13320 Bouc Bel Air, France. Chemin Houle, F-84820 Visan, France. Ctr Sante, Grand Santi 97340, French Guiana. Univ Montpellier 2, F-34000 Montpellier, France. ICIPE, Biodivers & Conservat Programme, Nairobi, Kenya. RP Basset, Y (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Ancon, Panama. RI Basset, Yves/B-6642-2014 NR 79 TC 65 Z9 70 U1 1 U2 18 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0024-4066 J9 BIOL J LINN SOC JI Biol. J. Linnean Soc. PD APR PY 2001 VL 72 IS 4 BP 585 EP 607 DI 10.1111/j.1095-8312.2001.tb01340.x PG 23 WC Evolutionary Biology SC Evolutionary Biology GA 437RM UT WOS:000169007400008 ER PT J AU Olson, SL AF Olson, SL TI Why so many kinds of passerine birds? SO BIOSCIENCE LA English DT Letter ID EVOLUTION; DIVERSITY; EOCENE C1 Natl Museum Nat Hist, Dept Vertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. RP Olson, SL (reprint author), Natl Museum Nat Hist, Dept Vertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. NR 14 TC 7 Z9 9 U1 1 U2 3 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD APR PY 2001 VL 51 IS 4 BP 268 EP 269 DI 10.1641/0006-3568(2001)051[0268:WSMKOP]2.0.CO;2 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 436XA UT WOS:000168960100002 ER PT J AU Von Sternberg, R Cumberlidge, N AF Von Sternberg, R Cumberlidge, N TI On the Heterotreme-Thoracotreme distinction in the Eubrachyura De Saint Laurent, 1980 (decapoda, brachyura) SO CRUSTACEANA LA English DT Article ID CRUSTACEA; CRABS; PHYLOGENY AB Eubrachyurans are currently divided into two subsections based on the anatomical position of the seminal duct termini. Heterotremes have the seminal ducts passing through the pereiopod 5 coxae, emerging externally in the form of "penes" to contact the basal segments of the gonopods. Thoracotrematous crabs, on the other hand, have the "male openings" located on sternite 8 and the ejaculatory ducts never pass through the pereiopod 5 coxae. Some brachyurologists maintain in the literature that the heterotreme-thoracotreme distinction reflects the extremes of two evolutionary grades. According to this speculation, "advanced" thoracotrematous crabs probably arose from intermediate goneplacid forms which, in turn, originated out of the Heterotremata in response to selection pressures for improved locomotion. The cladistic hypothesis of De Saint Laurent (1980), in contrast, positions Heterotremata and Thoracotremata as sister groups. Indeed, the heterotremethoracotreme difference considered alone does support two discrete types as no truly intermediate seminal duct condition bridges the subsections. Nor is there any evidence to suggest that the heterotrematous state is the anatomical precursor of sternal openings for the seminal ducts. The fact that basal members of the Pinnotheroidea De Haan are thoracotremes whereas more derived forms have an heterotrematous morphology, refutes De Saint Laurent's hypothesis of a deep phylogenetic cleavage between the two subsections. In addition to this information, the 850+ species of freshwater crabs (many of which are semi-terrestrial) share an array of somatic apomorphies with thoracotremes and yet belong to the Heterotremata. And the cladistic hypothesis of De Saint Laurent (1980) is also falsified by previous parsimony analyses which place a monophyletic taxon Thoracotremata within a paraphyletic group Heterotremata. It is therefore possible that Heterotremata is synonomous with Eubrachyura, with Thoracotremata remaining as a distinct eubrachyuran subclade. One trenchant conclusion is that the functional explanation for the heterotreme-thoracotreme distinction lacks empirical support. C1 Smithsonian Inst, Dept Invertebrate Zool, Washington, DC 20560 USA. No Michigan Univ, Dept Biol, Marquette, MI 49855 USA. RP Von Sternberg, R (reprint author), Smithsonian Inst, Dept Invertebrate Zool, NHB-163, Washington, DC 20560 USA. NR 30 TC 10 Z9 10 U1 0 U2 6 PU BRILL ACADEMIC PUBLISHERS PI LEIDEN PA PLANTIJNSTRAAT 2, P O BOX 9000, 2300 PA LEIDEN, NETHERLANDS SN 0011-216X J9 CRUSTACEANA JI Crustaceana PD APR PY 2001 VL 74 BP 321 EP 338 DI 10.1163/156854001300104417 PN 4 PG 18 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 439EC UT WOS:000169097000001 ER PT J AU Zalucki, MP Brower, LP Alonso, A AF Zalucki, MP Brower, LP Alonso, A TI Detrimental effects of latex and cardiac glycosides on survival and growth of first-instar monarch butterfly larvae Danaus plexippus feeding on the sandhill milkweed Asclepias humistrata SO ECOLOGICAL ENTOMOLOGY LA English DT Article DE catalepsis; co-evolutionary arms race; experimental study; feeding behaviour; miring; mortality; novel technique; petiole notching; plant defences; toxicosis ID CARDENOLIDE CONTENT; PLANT DEFENSE; LEPIDOPTERA; OVIPOSITION; BEHAVIOR; POPULATION; CALIFORNIA; ERIOCARPA; LEAVES; ENERGY AB 1. A novel experimental method was developed to study negative physical and chemical effects of latex and cardiac glycosides on first-instar monarch butterfly larvae in their natural environment in north central Florida. Forceps were used to nibble through the petioles of leaves of the sandhill milkweed Asclepias humistrata, mimicking the behaviour of mature monarch larvae. This notching cut off the supply-of latex to the leaves without significantly reducing either their cardiac glycoside concentration or water content. 2. The mean cardiac glycoside concentration in larvae that fed on intact leaves was nearly two: and a half times greater than in larvae that fed on notched leaves. This was probably because more latex is present in the gut of the larvae that fed on the intact leaves. Supporting this is the fact that the mean concentration of cardiac glycosides in the latex was 34-47 times that in the leaves. 3. Wet weights, dry weights, and growth rates of first-instar larvae that fed on intact leaves over a 72-h period were less than half those of larvae that fed on notched leaves. 4. Mortality due to miring in the latex was 27% on the intact leaves compared with 2% on the notched leaves. 5. Latex, cardiac glycosides, and other as yet undetermined plant factors all have a negative effect on:first-instar larval survival. 6. Video-analyses indicated that ingestion of latex caused the larvae to become cataleptic and increased their chances of being mired on the leaf by the setting latex glue. Dysfunction resulting from latex ingestion may lead to the larvae falling off the plant and being killed by invertebrate predators. 7. The difficulty of neonate monarch larvae surviving on A. humistrata - one of the principal milkweed species fed on each spring as monarchs remigrate from Mexico into the southern U.S.A. - is evidence that a co-evolutionary arms race is operating in this plant-herbivore system. C1 Sweet Briar Coll, Dept Biol, Sweet Briar, VA 24595 USA. Univ Queensland, Dept Zool & Entomol, St Lucia, Qld 4067, Australia. Smithsonian Inst, Washington, DC 20560 USA. RP Brower, LP (reprint author), Sweet Briar Coll, Dept Biol, Sweet Briar, VA 24595 USA. RI Zalucki, Myron/G-7983-2012 OI Zalucki, Myron/0000-0001-9603-7577 NR 56 TC 80 Z9 82 U1 6 U2 34 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0307-6946 J9 ECOL ENTOMOL JI Ecol. Entomol. PD APR PY 2001 VL 26 IS 2 BP 212 EP 224 DI 10.1046/j.1365-2311.2001.00313.x PG 13 WC Entomology SC Entomology GA 424WB UT WOS:000168256000014 ER PT J AU Dalling, JW Winter, K Nason, JD Hubbell, SP Murawski, DA Hamrick, JL AF Dalling, JW Winter, K Nason, JD Hubbell, SP Murawski, DA Hamrick, JL TI The unusual life history of Alseis blackiana: A shade-persistent pioneer tree? SO ECOLOGY LA English DT Article DE Alseis blackiana; functional group; Miconia argentea; ontogeny; pioneer; regeneration guild; seed germination; seedling growth; shade tolerance; Tetragastris panamensis ID LOWLAND TROPICAL FOREST; GAP-PHASE REGENERATION; SOIL SEED BANK; RAIN-FOREST; RELATIVE IMPORTANCE; NEOTROPICAL FOREST; GROWTH-RESPONSES; LIGHT GRADIENT; GUILD CONCEPT; LIVED LEAVES AB Classifications of tree species into regeneration guilds or functional groups are often based on a limited number of life history characteristics indicative of requirements for early establishment, with the assumption that these traits are correlated with growth requirements of larger individuals. We tested the validity of this assumption for Alseis blackiana, a common canopy tree in central Panama, by examining its seed germination, seedling growth, and sapling distribution, growth, and mortality. We found that the early life history of Alseis is characteristic of pioneer species: the seed germination rate was much higher in forest gaps than in the forest understory, small seedlings were absent from the understory, and seedlings showed strong plastic responses to variation in light. Seedling relative growth rate, leaf area production rate, and maximum carbon assimilation rates of Alseis are much more similar to those of the pioneer tree Miconia argentea than to those of the non-pioneer tree Tetragastris panamensis. However, in contrast to Miconia, established seedlings of Alseis are capable of remarkable persistence in the understory; in a 1-ha plot on Barro Colorado Island, the mortality rate for 722 saplings <1 cm dbh was <4% per year between 1986 and 1998. We suspect that shade tolerance in Alseis is achieved by both physiological and morphological adaptations, e.g., efficient light interception by thin, nonoverlapping leaves, tolerance to litterfall damage, and a high resprouting capacity. These results show that existing functional group classifications do not account for the full range of seedling trait combinations found in tropical trees and indicate that a gap requirement for seedling establishment need not limit the abundance of adult individuals in a stand. C1 Univ Georgia, Dept Bot, Athens, GA 30602 USA. Harvard Univ Hebaria, Cambridge, MA 02138 USA. Smithsonian Tropic Res Inst, Washington, DC 20560 USA. Univ Iowa, Dept Sci Biol, Iowa City, IA 52242 USA. RP Dalling, JW (reprint author), Dept Plant Biol, 505 S Goodwin Ave, Urbana, IL 61801 USA. EM dallingj@life.uiuc.edu NR 72 TC 51 Z9 59 U1 1 U2 19 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 0012-9658 J9 ECOLOGY JI Ecology PD APR PY 2001 VL 82 IS 4 BP 933 EP 945 PG 13 WC Ecology SC Environmental Sciences & Ecology GA 422TJ UT WOS:000168135100003 ER PT J AU Aguilar, S Condit, R AF Aguilar, S Condit, R TI Use of native tree species by an Hispanic community in Panama SO ECONOMIC BOTANY LA English DT Article DE native trees; Panama; local plant uses; Hispanic community AB We investigated the use of plants collected in the wild by a small farming community in Central Panama to document the importance of noncultivated plants by tropical, nonforest-dwelling, nonindigenous people. Ve visited the community to observe what wood was used to build houses and interviewed local people about medicinal and edible plants collected in the wild state. The community reported use of 119 noncultivated plant species, including 108 tree species, three shrubs, two herbs, four lianas, and two vines. The majority (71) of the species were used for building homes. Other products built with wood collected in the wild were diverse kinds of tools, containers, cages, and fences. The second most important use of wild plants, in terms of number of species, was firewood, for which 40 species were mentioned by the community. Other uses included fruit for human consumption (20 species). Most of the species (82 of 119) were collected in secondary forests near the community, whereas another large group (47 species) were collected in mature forest. Fewer species were harvested in shrubby regrowth or from isolated trees in farm land. Nearly all the species (111 of 119) were native to the area, and never cultivated locally, but 15 species were considered especially valuable, and were often protected when found as juveniles. Only six of the species are commonly used in reforestation programs in Panama. We conclude that even hispanic communities in tropical Latin America, living outside the forest, with no Amerindian inhabitants, make frequent use of the great diversity of trees native to the region. C1 Smithsonian Trop Res Inst, Ctr Trop Forest Sci, Unit 0948, APO, AA 34002 USA. RP Aguilar, S (reprint author), Smithsonian Trop Res Inst, Ctr Trop Forest Sci, Unit 0948, APO, AA 34002 USA. NR 52 TC 24 Z9 24 U1 4 U2 9 PU NEW YORK BOTANICAL GARDEN PI BRONX PA PUBLICATIONS DEPT, BRONX, NY 10458 USA SN 0013-0001 J9 ECON BOT JI Econ. Bot. PD APR-JUN PY 2001 VL 55 IS 2 BP 223 EP 235 DI 10.1007/BF02864560 PG 13 WC Plant Sciences SC Plant Sciences GA 457QY UT WOS:000170149300007 ER PT J AU Ogden, JC AF Ogden, JC TI Maintaining diversity in the oceans - Issues for the new US administration SO ENVIRONMENT LA English DT Article ID SEA OTTERS; BIODIVERSITY; ECOSYSTEMS; ECOLOGY; FUTURE C1 Univ S Florida, Tampa, FL 33620 USA. Smithsonian Trop Res Inst, Balboa, Panama. Florida Inst Oceanog, St Petersburg, FL USA. NR 34 TC 4 Z9 4 U1 0 U2 2 PU HELDREF PUBLICATIONS PI WASHINGTON PA 1319 EIGHTEENTH ST NW, WASHINGTON, DC 20036-1802 USA SN 0013-9157 J9 ENVIRONMENT JI Environment PD APR PY 2001 VL 43 IS 3 BP 28 EP 37 PG 10 WC Environmental Sciences; Environmental Studies SC Environmental Sciences & Ecology GA 450XE UT WOS:000169769500004 ER PT J AU Hakenkamp, CC Ribblett, SG Palmer, MA Swan, CM Reid, JW Goodison, MR AF Hakenkamp, CC Ribblett, SG Palmer, MA Swan, CM Reid, JW Goodison, MR TI The impact of an introduced bivalve (Corbicula fluminea) on the benthos of a sandy stream SO FRESHWATER BIOLOGY LA English DT Article DE Corbicula; meiofauna; protists; stream benthos ID MUSSEL DREISSENA-POLYMORPHA; FRESH-WATER ECOSYSTEMS; ZEBRA MUSSEL; ASIATIC CLAM; MACROINVERTEBRATE COMMUNITIES; BIOLOGICAL INVASIONS; PIEDMONT STREAM; POTOMAC RIVER; NORTH-AMERICA; HUDSON-RIVER AB 1. The effect of an exotic, burrowing bivalve (Corbicula fluminea) on the benthic fauna of a sandy-bottomed stream was assessed by field and laboratory experiments. Corbicula differs from other freshwater, non-native bivalves in that it both filter- and pedal-feeds and thus has the potential to influence the streambed community in different ways. 2. In the field, cages were used to vary the abundance of Corbicula in the streambed. Increasing abundance of Corbicula was negatively associated with the abundance of benthic bacteria and flagellates but had no apparent effect on other protists or meiofauna. 3. In the laboratory, we compared the effect of Corbicula on the benthic community when the bivalves were able both to filter- and pedal-feed with that when they were able only to filter-feed. Bivalves restricted to filter-feeding were placed in sediment lacking benthic fauna and organic matter, then the benthos in nearby natural sediment was compared with the community present when Corbicula was able to move freely through the sediment and both to filter- and pedal-feed. Corbicula able to pedal-feed were again associated with a decreased abundance of benthic flagellates and bacteria, as well as diatoms. C1 James Madison Univ, Dept Biol, Harrisonburg, VA 22807 USA. Univ Maryland, Dept Biol, College Pk, MD USA. Smithsonian Inst, Museum Natl Hist Nat, Dept Invertebrate Zool, Washington, DC USA. RP Hakenkamp, CC (reprint author), James Madison Univ, Dept Biol, MSC7801, Harrisonburg, VA 22807 USA. RI Ross, Donald/F-7607-2012; OI Ross, Donald/0000-0002-8659-3833; Swan, Christopher/0000-0002-9763-9630 NR 58 TC 58 Z9 58 U1 3 U2 36 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0046-5070 J9 FRESHWATER BIOL JI Freshw. Biol. PD APR PY 2001 VL 46 IS 4 BP 491 EP 501 DI 10.1046/j.1365-2427.2001.00700.x PG 11 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 426ZU UT WOS:000168380900005 ER PT J AU MacLeod, KG Huber, BT Fullagar, PD AF MacLeod, KG Huber, BT Fullagar, PD TI Evidence for a small (similar to 0.000030) but resolvable increase in seawater Sr-87/Sr-86 ratios across the Cretaceous-Tertiary boundary SO GEOLOGY LA English DT Article DE Cretaceous-Tertiary boundary; reworking; foraminifera; extinction; strontium; chemostratigraphy ID STRONTIUM ISOTOPE STRATIGRAPHY AB Previous studies of Sr-87/Sr-86 patterns across the Cretaceous-Tertiary (K-T) boundary have generated inconsistent results. Analyses of samples from Ocean Drilling Program Hole 1049C provide better taphonomic and diagenetic control than has been previously achieved and indicate (1) that there was a rapid increase of similar to0.000 030 in seawater Sr-87/Sr-86 ratios across the K-T boundary, (2) that post-K-T Cretaceous foraminifera at this site are reworked, and (3) that subtle diagenetic overprinting affects the basal similar to 15 cm of the Danian ooze. These conclusions are consistent with the asteroid impact hypothesis. Reworking rather than survivorship confirms nearly complete extinction of Cretaceous Tethyan planktic foraminifera; the Sr-87/Sr-86 excursion can be explained by enhanced continental weathering, perhaps related to acid rain in the aftermath of the K-T impact. C1 Univ Missouri, Dept Geol Sci, Columbia, MO 65211 USA. Smithsonian Inst, Dept Paleobiol, MRC, Washington, DC 20560 USA. Univ N Carolina, Dept Geol Sci, Chapel Hill, NC 27599 USA. RP MacLeod, KG (reprint author), Univ Missouri, Dept Geol Sci, Columbia, MO 65211 USA. RI MacLeod, Kenneth/C-4042-2017 OI MacLeod, Kenneth/0000-0002-6016-0837 NR 13 TC 23 Z9 24 U1 0 U2 1 PU GEOLOGICAL SOC AMERICA, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD APR PY 2001 VL 29 IS 4 BP 303 EP 306 DI 10.1130/0091-7613(2001)029<0303:EFASBR>2.0.CO;2 PG 4 WC Geology SC Geology GA 414YP UT WOS:000167694000004 ER PT J AU Zimbelman, JR AF Zimbelman, JR TI Image resolution and evaluation of genetic hypotheses for planetary landscapes SO GEOMORPHOLOGY LA English DT Article DE Earth; planetary landscape; genetic hypothesis ID THERMAL EMISSION SPECTROMETER; LUNAR SURFACE FEATURES; MARS GLOBAL SURVEYOR; IMPACT CRATERS; LASER ALTIMETER; MARTIAN SURFACE; SINUOUS RILLES; MAGELLAN DATA; VENUS; WATER AB The spatial resolution of image data tends to constrain the horizontal length scale of genetic hypotheses that are addressable by those data. No 'simple' formula exists when image resolution is sufficient to test a given geomorphic process, which is dependent on what characteristics are diagnostic of the particular process. Genetic hypotheses should be formulated along the lines of the "multiple working hypotheses" concept as described in a classic paper by Chamberlin [J, Geol, 5 (1897) 837]. An essential element of a viable working hypothesis is a clear indication of the characteristics predicted by, or a consequence of, the hypothesis. An untestable hypothesis is not an effective working hypothesis. The history of the study of lunar sinuous rilles is outlined as an illustration of the influence of image resolution and the formulation of genetic hypotheses on the subsequent advancement of understanding of the problem. Sinuous rilles on Venus and Mars, and controversial sinuous ridges on Mars are also reviewed. In the lunar case, the three-order-of-magnitude improvement in spatial resolution provided by Lunar Orbiter photographs over Earth-based telescopic photographs did nor result in definitive examination and elimination of published hypotheses for the formation of sinuous rilles. Topographic data obtained from cartographically controlled Apollo orbital photographs, along with important observations and samples obtained by the astronauts on the lunar surface, did test and exclude several hypotheses. The formulation of a genetic hypothesis, including testable consequences of that hypothesis, is a greater determinant of its ultimate utility to the scientific community than is the image resolution available at any,given time. Published by Elsevier Science B.V. C1 Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, Washington, DC 20560 USA. RP Zimbelman, JR (reprint author), Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, Washington, DC 20560 USA. EM jrz@ceps.nasm.edu NR 82 TC 24 Z9 24 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-555X J9 GEOMORPHOLOGY JI Geomorphology PD APR PY 2001 VL 37 IS 3-4 SI SI BP 179 EP 199 DI 10.1016/S0169-555X(00)00082-9 PG 21 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 413YF UT WOS:000167638600002 ER PT J AU von Sternberg, R Cumberlidge, N AF von Sternberg, R Cumberlidge, N TI Notes on the position of the true freshwater crabs within the brachyrhynchan Eubrachyura (Crustacea : Decapoda : Brachyura) SO HYDROBIOLOGIA LA English DT Article DE Crustacea; freshwater crabs; Pseudothelphusidae; Potamoidea; Thoracotremata; Eubrachyura; cladistics; phenetics ID WATER CRABS; GECARCINUCOIDEA AB Cladistic and phenetic relationships of 51 eubrachyuran crab genera, comprising 36 genera of marine crabs and 18 genera of true freshwater crabs from 7 families, were investigated using 121 parsimony-informative adult morphological characters. The data matrix was subjected to four different treatments: (1) a cladistic analysis with a combination of unordered and ordered characters, (2) a cladistic analysis with all characters unordered, (3) neighbour-joining, and (4) UPGMA phenetic analyses. The parsimony analysis conducted with a combination of ordered and unordered characters produced a set of hypotheses which supported monophyly of a Pseudothelphusidae+Potamoidea clade. Furthermore, exemplar genera of the Bythograeidae and Pinnotheridae formed an unresolved polytomy with the Pseudothelphusidae+Potamoidea group, the Thoracotremata. The trichodactylid freshwater crabs were positioned as the sister taxon of the basal portunoid Carcinus, but were unresolved relative to other portunoids and geryonids. Second, the parsimony analysis conducted with all characters unordered resulted in a [bythograeid, pseudothelphusid+potamoid, pinnotherid, thoracotreme] group with no hierarchical resolution, which in turn formed a polytomy with a goneplacid+portunoid clade and a polyphyletic Xanthoidea. And third, phenetic groupings of the eubrachyuran genera invariably placed the pseudothelphusids with the potamoids, and this clustered with a group containing the thoracotremes (either in whole or part). Support was thus found for morphological connections among the nontrichodactylid freshwater crabs, thoracotremes, bythograeids, and pinnotherids, and for the placement of the trichodactylids within the Portunoidea. These two latter findings (that used a range of genera from each family) are broadly congruent with a previous cladistic analysis of selected eubrachyuran familial groundpatterns that used a basal exemplar of each marine and freshwater crab family (Sternberg et al., 1999). However, it is clear that the large scale homoplasy identified here may nullify any reliable hypothesis of brachyrhynchan groupings at this stage. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, Washington, DC 20560 USA. No Michigan Univ, Dept Biol, Marquette, MI 49855 USA. RP von Sternberg, R (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Systemat Biol, NHB-163, Washington, DC 20560 USA. NR 27 TC 11 Z9 11 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD APR PY 2001 VL 449 IS 1-3 BP 21 EP 39 PG 19 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 456AK UT WOS:000170059800002 ER PT J AU Ceruzzi, P AF Ceruzzi, P TI Systems, experts, and computers: The systems approach in management and engineering, World War II and after SO IEEE ANNALS OF THE HISTORY OF COMPUTING LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Ceruzzi, P (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 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 90720-1314 USA SN 1058-6180 J9 IEEE ANN HIST COMPUT JI IEEE Ann. Hist. Comput. PD APR-JUN PY 2001 VL 23 IS 2 BP 74 EP 75 DI 10.1109/MAHC.2001.929914 PG 2 WC Computer Science, Theory & Methods; History & Philosophy Of Science SC Computer Science; History & Philosophy of Science GA 441ET UT WOS:000169218600008 ER PT J AU Lubar, S AF Lubar, S TI Robe Sapiens: Evolution of a new species SO IEEE ANNALS OF THE HISTORY OF COMPUTING LA English DT Book Review C1 Smithsonian Inst, NMAH, Washington, DC 20560 USA. RP Lubar, S (reprint author), Smithsonian Inst, NMAH, Washington, DC 20560 USA. NR 1 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 90720-1314 USA SN 1058-6180 J9 IEEE ANN HIST COMPUT JI IEEE Ann. Hist. Comput. PD APR-JUN PY 2001 VL 23 IS 2 BP 77 EP 77 PG 1 WC Computer Science, Theory & Methods; History & Philosophy Of Science SC Computer Science; History & Philosophy of Science GA 441ET UT WOS:000169218600010 ER PT J AU Leps, J Novotny, V Basset, Y AF Leps, J Novotny, V Basset, Y TI Habitat and successional status of plants in relation to the communities of their leaf-chewing herbivores in Papua New Guinea SO JOURNAL OF ECOLOGY LA English DT Article DE Euphorbiaceae; host specificity; Moraceae; plant palatability; rain forest ID TROPICAL RAIN-FOREST; LEAFHOPPERS AUCHENORRHYNCHA; SECONDARY SUCCESSION; INSECT HERBIVORES; SPECIES-DIVERSITY; EUPHORBIACEAE; BUTTERFLIES; SIZE; PALATABILITY; FICUS AB 1 The spatial distribution of 30 woody species (15 species each of Euphorbiaceae and Moraceae) and their associated leaf-chewing communities (Orthoptera, Phasmatodea, Coleoptera and Lepidoptera) were studied in coastal, riverine and rain forest habitats. A successional series, from abandoned gardens to primary forest, was examined. Host plant records for more than 27 000 insects, all verified by feeding experiments, and spatial distribution of almost 9000 plant specimens were evaluated. 2 Phylogenetic (taxonomic) relatedness of host plants explained 56% of the variability in the composition of their herbivore communities, while the ecological (distribution) similarity of plants explained only 4%. 3 The successional optimum of plant species was not an important determinant of the composition of their herbivore communities. 4 Neither plant successional optimum nor plant palatability to a generalist herbivore were correlated with the number of species, abundance or host specificity of its herbivores, nor was there a correlation between a plant's palatability to a generalist herbivore and its successional optimum. 5 Herbivore communities became dominated increasingly by a few abundant species in later stages of succession. 6 On average, Ficus species had lower palatability and supported more species of herbivores than species of Euphorbiaceae. The abundance of herbivores and their dominance index were not significantly different between the two plant families. 7 These results contradict several previous studies of successional trends in temperate regions. Many tropical successions, however, start with pioneer trees, rather than with annual herbs, and may present a permanent and predictable habitat for insects even at the earliest stages, with no advantage for polyphagous species. Numerous pioneer trees in the tropics possess anti-herbivore defences, resulting in their low palatability to generalists, increased host specificity of herbivores, and often idiosyncratic composition of herbivore communities. Even plant traits such as species richness of their herbivores or palatability may have a phylogenetic component which should not be ignored. C1 Univ S Bohemia, Fac Biol, Ceske Budejovice 37005, Czech Republic. Acad Sci Czech Republic, Inst Entomol, CR-37005 Ceske Budejovice, Czech Republic. Bernice P Bishop Museum, Dept Nat Sci, Honolulu, HI USA. Smithsonian Trop Res Inst, Balboa, Ancon, Panama. RP Univ S Bohemia, Fac Biol, Branisovska 31, Ceske Budejovice 37005, Czech Republic. EM suspa@entu.cas.cz RI Leps, Jan/B-6913-2013; Basset, Yves/B-6642-2014; Novotny, Vojtech/G-9434-2014 OI Leps, Jan/0000-0002-4822-7429; Novotny, Vojtech/0000-0001-7918-8023 NR 77 TC 56 Z9 58 U1 4 U2 28 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0022-0477 EI 1365-2745 J9 J ECOL JI J. Ecol. PD APR PY 2001 VL 89 IS 2 BP 186 EP 199 DI 10.1046/j.1365-2745.2001.00540.x PG 14 WC Plant Sciences; Ecology SC Plant Sciences; Environmental Sciences & Ecology GA 432LC UT WOS:000168692200005 ER PT J AU Jett, JA AF Jett, JA TI Recent literature on foraminifera SO JOURNAL OF FORAMINIFERAL RESEARCH LA English DT Bibliography C1 Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. RP Jett, JA (reprint author), Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CUSHMAN FOUNDATION FORAMINIFERAL RES PI CAMBRIDGE PA MUSEUM COMPARATIVE ZOOLOGY, DEPT INVERTEBRATE PALEONTOLOGY 26 OXFORD ST, HARVARD UNIV, CAMBRIDGE, MA 02138 USA SN 0096-1191 J9 J FORAMIN RES JI J. Foraminifer. Res. PD APR PY 2001 VL 31 IS 2 BP 164 EP 167 DI 10.2113/0310164 PG 4 WC Paleontology SC Paleontology GA 434XK UT WOS:000168841000008 ER PT J AU Kensley, B Chan, TY AF Kensley, B Chan, TY TI Two species of deep-sea flabelliferan isopods from Taiwan (Crustacea : Peracarida : Aegidae, Anuropidae) SO JOURNAL OF NATURAL HISTORY LA English DT Article DE Isopoda; Flabellifera; Aegidae; Anuropidae; Taiwan ID CIROLANIDAE; CYMOTHOIDAE; PACIFIC; FISHES AB Aega falcata sp. nov. is described from two female specimens from about 500 m off Taiwan. The species' most distinctive feature, which readily distinguishes it from all others described, is the flattened falcate plates of the two basal articles of the antennular peduncle. Three specimens of Anuropus pacificus Lincoln and Jones, 1973, are recorded from 400 to 500 m. These include a male, an ovigerous and a larvigerous female having numerous manca in the broodpouch. Given the rarity of specimens of Anuropus, all three forms, as well as the manca, are described in some detail. C1 Smithsonian Inst, Museum Natl Hist Nat, Dept Invertebrate Zool, Washington, DC 20560 USA. Natl Taiwan Ocean Univ, Inst Marine Biol, Chilung 20224, Taiwan. RP Kensley, B (reprint author), Smithsonian Inst, Museum Natl Hist Nat, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 37 TC 9 Z9 11 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0022-2933 J9 J NAT HIST JI J. Nat. Hist. PD APR PY 2001 VL 35 IS 4 BP 481 EP 496 DI 10.1080/00222930151098152 PG 16 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 424YK UT WOS:000168261400002 ER PT J AU Ruiz, M Pelaez, J Lorenzini, EC AF Ruiz, M Pelaez, J Lorenzini, EC TI On the stability of a tethered system with a free end in elliptic orbit SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article ID INJECTION; DYNAMICS AB The transverse oscillations of a tethered system with a free end in elliptic Orbit are considered. These are important in certain momentum transfer maneuvers with tethers. To first approximation, transverse and longitudinal oscillations are decoupled. The equations for the former lead to a Sturm-Liouville problem, so that the eigenvalues and eigenfunctions can be determined. A specific example is chosen to reduce the number of free parameters and provide numerical evidence for the theory developed. For this case, eigenvalues are computed and the time equations are numerically integrated for each mode, finding instabilities in some modes. Some are due to resonance, some to loss of tether tension. Small changes in the system mass distribution can improve stability. C1 Univ Politecn Madrid, ETSI Aeronaut, E-28040 Madrid, Spain. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Ruiz, M (reprint author), Univ Politecn Madrid, ETSI Aeronaut, Pza Cardenal Cisneros,3, E-28040 Madrid, Spain. RI Pelaez, Jesus/M-7806-2016 OI Pelaez, Jesus/0000-0001-9755-1674 NR 34 TC 3 Z9 3 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 2001 VL 49 IS 2 BP 237 EP 253 PG 17 WC Engineering, Aerospace SC Engineering GA 510AE UT WOS:000173185900002 ER PT J AU Mair, RW Hurlimann, MD Sen, PN Schwartz, LM Patz, S Walsworth, RL AF Mair, RW Hurlimann, MD Sen, PN Schwartz, LM Patz, S Walsworth, RL TI Tortuosity measurement and the effects of finite pulse widths on xenon gas diffusion NMR studies of porous media SO MAGNETIC RESONANCE IMAGING LA English DT Article; Proceedings Paper CT 5th International Meeting on Recent Advances in Magnetic Resonance Applications to Porous Media CY OCT 09-11, 2000 CL UNIV BOLOGNA, BOLOGNA, ITALY HO UNIV BOLOGNA DE xenon; diffusion; PGSE; tortuosity; porous media ID FIELD-GRADIENT NMR; TO-VOLUME RATIO; RESTRICTED DIFFUSION; COEFFICIENT; PROBE; FLUIDS; ROCKS AB We have extended the utility of NMR as a technique to probe porous media structure over length scales of similar to 100-2000 mum by using the spin 1/2 noble gas Xe-129 imbibed into the system's pore space. Such length scales are much greater than can be probed with NMR diffusion studies of water-saturated porous media. We utilized Pulsed Gradient Spin Echo NMR measurements of the time-dependent diffusion coefficient, D(t), of the xenon gas filling the pore space to study further the measurements of both the pore surface-area-to-volume ratio, S/V-p, and the tortuosity (pore connectivity) of the medium. In uniform-size glass bead packs, we observed D(t) decreasing with increasing t, reaching an observed asymptote of similar to0.62-0.65D(0) that could be measured over diffusion distances extending over multiple bead diameters. Measurements of D(t)/D-0 at differing gas pressures showed this tortuosity Emit was not affected by changing the characteristic diffusion length of the spins during the diffusion encoding gradient pulse. This was not the case at the short time limit, where D(t)/D-0 was noticeably affected by the gas pressure in the sample. Increasing the gas pressure, and hence reducing D-0 and the diffusion during the gradient pulse served to reduce the previously observed deviation of D(t)/D-0 from the S/V-p relation. The Fade approximation is used to interpolate between the long and short time limits in D(t). While the short time D(t) points lay above the interpolation line in the case of small beads, due to diffusion during the gradient pulse on the order of the pore size, it was also noted that the experimental D(t) data fell below the Fade line in the case of large beads, most likely due to finite size effects. (C) 2001 Elsevier Science Inc. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Schlumberger Doll Res, Ridgefield, CT 06877 USA. Brigham & Womens Hosp, Dept Radiol, Boston, MA 02115 USA. RP Mair, RW (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Patz, Samuel/I-2879-2012 FU NCRR NIH HHS [R21 RR014297-01A18280, R21 RR014297-01A1] NR 23 TC 38 Z9 38 U1 1 U2 9 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0730-725X J9 MAGN RESON IMAGING JI Magn. Reson. Imaging PD APR-MAY PY 2001 VL 19 IS 3-4 BP 345 EP 351 DI 10.1016/S0730-725X(01)00247-8 PG 7 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 455YU UT WOS:000170056000011 PM 11445310 ER PT J AU Sikaroodi, M Lawrey, JD Hawksworth, DL Depriest, PT AF Sikaroodi, M Lawrey, JD Hawksworth, DL Depriest, PT TI The phylogenetic position of selected lechenicolous fungi: Hobsonia, Illosporium, and Marchandiomyces SO MYCOLOGICAL RESEARCH LA English DT Article ID RIBOSOMAL-RNA GENES; SACCHAROMYCES CEREVISIAE; LICHENICOLOUS FUNGI; PCR PRIMERS; SYMBIOSES; SEQUENCE; RDNA; DNA AB The genera Hobsonia. Illosporium, and Marchandiomyces include several common lichenicolous (lichen-inhabiting) species that have been taxonomically linked in the past. These mitosporic genera are frequently misidentified because of a paucity of morphological characters, which has led to some confusion about their relationships. We examined the phylogenetic positions of species in these genera using complete sequences of the small subunit (SSU) and internal transcribed spacer (ITS) ribosomal DNA (rDNA), and portions of the mitochondrial (mt) SSU rDNA obtained from isolated cultures of freshly collected specimens. Phylogenetic analysis of the sequence data indicated that Marchandiomyces corallinus and M. aurantiacus are closely related members of a basidiomycete clade. In addition, the clade includes an undescribed non-lichenicolous species that is morphologically similar to M, corallinus. Another undescribed species with marchandiomyces-like sclerotia, appears to be in a separate basidiomycete clade. The three recognized species of Hobsonia are unrelated, with H. christiansenii appearing to be a hypocrealean ascomycete closely related to a sample of Illosporium carneum. H. santessonii an ascomycete of unknown affinity, and H. mirabilis a basidiomycete. The latter, a plant pathogen, is the type species of Hobsonia. The new generic names Illosporiopsis and Hobsoniopsis gene. nov. are described for the lichenicolous species H. christiansenii and H. santessonii, respectively, and the necessary new combinations made. C1 Smithsonian Inst, Dept Bot, Washington, DC 20560 USA. George Mason Univ, Dept Biol, Fairfax, VA 22030 USA. Univ Complutense, Fac Farm, Dept Biol Vegetal 2, E-28040 Madrid, Spain. RP Depriest, PT (reprint author), Smithsonian Inst, Dept Bot, Washington, DC 20560 USA. RI DePriest, Paula/K-6633-2015 NR 31 TC 25 Z9 28 U1 0 U2 3 PU CAMBRIDGE UNIV PRESS PI PORT CHESTER PA 110 MIDLAND AVE, PORT CHESTER, NY 10573-9863 USA SN 0953-7562 J9 MYCOL RES JI Mycol. Res. PD APR PY 2001 VL 105 BP 453 EP 460 DI 10.1017/S0953756201003768 PN 4 PG 8 WC Mycology SC Mycology GA 432DT UT WOS:000168677500010 ER PT J AU Ahti, T DePriest, PT AF Ahti, T DePriest, PT TI New combinations of Cladina epithets in Cladonia (Ascomycotina : Cladoniaceae) SO MYCOTAXON LA English DT Article DE lichen-forming fungi; Lecanoromycetes; Lecanorales; nomenclature AB On the basis of our molecular phylogenetic results we propose that specific and infraspecific epithets currently placed in the segregate genus Cladina be transferred to the genus Cladonia, and that Cladina become a synonym of Cladonia. Of the almost fifty species and infraspecific taxa currently recognized as accepted names, we have identified 14 epithets at specific or infraspecific ranks that require transfer into the genus Cladonia. Of these, eight have never been placed in the genus and six have not been recognized at their proposed rank or position in Cladonia. In addition, the author citation of the name Cladina mills is corrected. C1 Univ Helsinki, Dept Systemat & Ecol, FIN-00014 Helsinki, Finland. Natl Museum Nat Hist, Dept Bot, Smithsonian Inst, Washington, DC 20560 USA. RP Ahti, T (reprint author), Univ Helsinki, Dept Systemat & Ecol, POB 47, FIN-00014 Helsinki, Finland. RI DePriest, Paula/K-6633-2015 NR 22 TC 14 Z9 15 U1 0 U2 0 PU MYCOTAXON LTD PI ITHACA PA PO BOX 264, ITHACA, NY 14851-0264 USA SN 0093-4666 J9 MYCOTAXON JI Mycotaxon PD APR-JUN PY 2001 VL 78 BP 499 EP 502 PG 4 WC Mycology SC Mycology GA 441NX UT WOS:000169237400034 ER PT J AU Fletcher, JD McShea, WJ Shipley, LA Shumway, D AF Fletcher, JD McShea, WJ Shipley, LA Shumway, D TI Use of common forest forbs to measure browsing pressure by white-tailed deer (Odocoileus virginianus Zimmerman) in Virginia, USA SO NATURAL AREAS JOURNAL LA English DT Article DE browse monitoring; foraging behavior; Odocoileus virginianus; understory plants; white-tailed deer ID FRAGMENTED DECIDUOUS FORESTS; POPULATIONS; INDICATORS; INTENSITY; L. AB The effect of browsing by white-tailed deer (Odocoileus virginianus Zimmerman) on reproductive activity of five understory plant taxa was examined using two deer exclosures in the Blue Ridge Mountains of Virginia, USA. Surveys were conducted within and outside of deer exclosures using 250-m(2) strip transects. Uvularia L. spp., Smilacina Desf. spp., Polygonatum Mill. spp., Orchis spectabilis L., and Arisaema triphyllum (L.) Schott were identified and counted, and noted for reproductive activity (presence of flowering and/or fruiting plants). Smilacina and Uvularia had more plants inside than outside of exclosures, whereas no significant differences in abundance were recorded for the other taxa. Reproductive activity of all taxa observed was greater inside than outside of exclosures. The survey method was field tested by determining the abundance and percent of plants reproductive at 11 sites along the Blue Ridge. Reproductive activity, for all taxa, was negatively correlated with deer abundance. This study demonstrates the potential for deer herbivory to affect herbaceous plant community composition and indicates that a measure of reproductive activity in common forest forbs would provide a rapid means to measure the severity of deer browsing on herbaceous species. C1 Smithsonian Inst, Conservat & Res Ctr, Front Royal, VA 22630 USA. Frostburg State Univ, Dept Biol, Frostburg, MD 21532 USA. Washington State Univ, Dept Nat Resource Sci, Pullman, WA 99164 USA. Frostburg State Univ, Dept Biol, Frostburg, MD 21532 USA. RP McShea, WJ (reprint author), Smithsonian Inst, Conservat & Res Ctr, 1500 Remount Rd, Front Royal, VA 22630 USA. NR 16 TC 25 Z9 25 U1 5 U2 23 PU NATURAL AREAS ASSOCIATION PI ROCKFORD PA 320 SOUTH THIRD STREET, ROCKFORD, IL 61104 USA SN 0885-8608 J9 NAT AREA J JI Nat. Areas J. PD APR PY 2001 VL 21 IS 2 BP 172 EP 176 PG 5 WC Ecology; Forestry SC Environmental Sciences & Ecology; Forestry GA 422VN UT WOS:000168140100007 ER PT J AU Wing, SL AF Wing, SL TI Hot times in the Bighorn Basin SO NATURAL HISTORY LA English DT Article C1 Smithsonian Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. RP Wing, SL (reprint author), Smithsonian Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER MUSEUM NAT HISTORY PI NEW YORK PA ATTN: LIBRARY SERIALS UNIT CENTRAL PK WEST AT 79TH ST, NEW YORK, NY 10024-5192 USA SN 0028-0712 J9 NAT HIST JI Nat. Hist. PD APR PY 2001 VL 110 IS 3 BP 48 EP 54 PG 7 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 415YW UT WOS:000167752000015 ER PT J AU MacLeod, KG Huber, BT Pletsch, T Rohl, U Kucera, M AF MacLeod, KG Huber, BT Pletsch, T Rohl, U Kucera, M TI Maastrichtian foraminiferal and paleoceanographic changes on Milankovitch timescales SO PALEOCEANOGRAPHY LA English DT Article ID CRETACEOUS PLANKTONIC-FORAMINIFERA; INOCERAMID EXTINCTION; ENVIRONMENTAL-CHANGES; EVOLUTIONARY HISTORY; TERTIARY BOUNDARY; CLIMATE; CIRCULATION; ATLANTIC; MODEL; OCEAN AB Milankovitch-scale alternations in Maastrichtian hemipelagic strata from Ocean Drilling Program Hole 1050C (Blake Nose) provide a natural experiment of paleoceanography and foraminiferal paleoecology in a tropical/subtropical greenhouse ocean. Cycles are 30-50 cm thick and thought to reflect the similar to 21 kyr precessional cycle. High planktic delta O-18 values are correlated with high planktic but low benthic delta C-13 values, indicating that cooler and/or more saline surface waters were associated with higher productivity. High-productivity intervals are also characterized by high Ca concentrations; enrichment in feldspar and kaolinite; and high relative abundance of Heterohelix spp., Globigerinelloides spp., and Laeviheterohelix glabrans, Conversely, low-productivity intervals have low planktic delta O-18 values; high Fe and Ti concentrations; enrichment in quartz, illite, and chlorite; and relative increases in Globotruncana spp, and Pseudoguembelina spp. Potential forcing mechanisms for observed covariation include cyclic variation in water column stratification, variation in continental nutrient fluxes, and changes in the intensity of upwelling. C1 Univ Missouri, Dept Geol Sci, Columbia, MO 65211 USA. Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. Univ Kiel, Inst Geowissensch, Kiel, Germany. Univ Bremen, Dept Geosci, D-28334 Bremen, Germany. Univ Calif Santa Barbara, Dept Geol Sci, Santa Barbara, CA 93106 USA. RP MacLeod, KG (reprint author), Univ Missouri, Dept Geol Sci, Columbia, MO 65211 USA. EM macleodk@missouri.edu; Huber.Brian@nmnh.si.edu; thomas.pletsch@uni-koeln.de; uroehl@allgeo.uni-bremen.de; kucera@mail.gl.rhul.ac.uk RI Kucera, Michal/B-9277-2009; Rohl, Ursula/G-5986-2011; MacLeod, Kenneth/C-4042-2017 OI Kucera, Michal/0000-0002-7817-9018; Rohl, Ursula/0000-0001-9469-7053; MacLeod, Kenneth/0000-0002-6016-0837 NR 92 TC 37 Z9 38 U1 4 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0883-8305 EI 1944-9186 J9 PALEOCEANOGRAPHY JI Paleoceanography PD APR PY 2001 VL 16 IS 2 BP 133 EP 154 DI 10.1029/2000PA000514 PG 22 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA 414YG UT WOS:000167693300001 ER PT J AU Duncan, BC Sanchez-Villicana, V Gould, PL Sadeghpour, HR AF Duncan, BC Sanchez-Villicana, V Gould, PL Sadeghpour, HR TI Measurement of the Rb(5D(5/2)) photoionization cross section using trapped atoms SO PHYSICAL REVIEW A LA English DT Article ID DIODE-LASER SYSTEM; ALKALI ATOMS; MAGNETOOPTICAL TRAP; EXCITED-STATES; VAPOR CELL; RB; CESIUM; CS AB We report on measurements of the cross section for photoionization of Rb atoms in the highly excited 5D(5/2) level at wavelengths ranging from 1064 to 532 nm (photoelectron energies of 0.175 to 1.33 eV). We efficiently populate the 5D(5/2) level using coherent two-photon excitation of trapped atoms with pulses in the counterintuitive order. The absolute photoionization cross sections are then measured via the increased loss of atoms from the magneto-optical trap when it is illuminated by the photoionizing light. Out results are in good agreement with new calculations based on the valence-electron parametric potential method. C1 Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Inst Astrofis Opt & Elect, Puebla 72840, Mexico. RP Duncan, BC (reprint author), Univ Connecticut, Dept Phys, U-3046, Storrs, CT 06269 USA. NR 30 TC 20 Z9 21 U1 2 U2 5 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 APR PY 2001 VL 63 IS 4 AR 043411 DI 10.1103/PhysRevA.63.043411 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 422AG UT WOS:000168095300084 ER PT J AU Korobov, VI AF Korobov, VI TI Relativistic corrections to the dipole polarizability of the ground state of the molecular ion H-2(+) SO PHYSICAL REVIEW A LA English DT Article ID MICROWAVE SPECTROSCOPY; RYDBERG STATES AB The recently reported precise experimental determination of the dipole polarizability of the H-2(+) molecular ion ground state [P.L. Jacobson, R.A. Komara, W.G. Sturrus, and S.R. Lundeen, Phys. Rev. A 62, 012509 (2000)] reveals a discrepancy between theory and experiment of about 0.0007a(0)(3), which has been attributed to relativistic and QED effects. In the present work we analyze an influence of the relativistic effects on the scalar dipole polarizability of an isolated H-2(+) molecular ion. Our conclusion is that it accounts for only 1/5 of the measured discrepancy. C1 Harvard Univ, Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Joint Inst Nucl Res, Dubna 141980, Russia. RP Korobov, VI (reprint author), Harvard Univ, Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RI Korobov, Vladimir/D-7849-2013 OI Korobov, Vladimir/0000-0003-3724-0270 NR 12 TC 17 Z9 17 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 2001 VL 63 IS 4 AR 044501 DI 10.1103/PhysRevA.63.044501 PG 3 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 422AG UT WOS:000168095300134 ER PT J AU Kink, I Laming, JM Takacs, E Porto, JV Gillaspy, JD Silver, E Schnopper, H Bandler, SR Barbera, M Brickhouse, N Murray, S Madden, N Landis, D Beeman, J Haller, EE AF Kink, I Laming, JM Takacs, E Porto, JV Gillaspy, JD Silver, E Schnopper, H Bandler, SR Barbera, M Brickhouse, N Murray, S Madden, N Landis, D Beeman, J Haller, EE TI Analysis of broadband x-ray spectra of highly charged krypton from a microcalorimeter detector of an electron-beam ion trap SO PHYSICAL REVIEW E LA English DT Article ID FE-XVII; NE-LIKE; PLASMAS; ATOMS; KR; COEFFICIENTS; ULTRAVIOLET; DENSITY; REGION; LINES AB Spectra of highly charged Kr ions, produced in an electron-beam ion trap (EBIT), have been recorded in a broad x-ray energy band (0.3 keV to 4 keV) with a microcalorimeter detector. Most of the spectral lines have been identified as transitions of B- to Al-like Kr. The transition energies have been determined with 0.2% uncertainty. A semi-empirical EBIT plasma model has been created to calculate a synthetic spectrum of highly charged Kr and to determine a charge state distribution of Kr ions inside the EBIT. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. USN, Res Lab, Washington, DC 20375 USA. MIT, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron GS Vaiana, Palermo, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Kink, I (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Bandler, Simon/A-6258-2010; OI Bandler, Simon/0000-0002-5112-8106; Brickhouse, Nancy/0000-0002-8704-4473 NR 48 TC 11 Z9 12 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD APR PY 2001 VL 63 IS 4 AR 046409 DI 10.1103/PhysRevE.63.046409 PN 2 PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 424CT UT WOS:000168215100065 PM 11308958 ER PT J AU Kirby, K Czujko, R Mulvey, P AF Kirby, K Czujko, R Mulvey, P TI The physics job market: From bear to bull in a decade SO PHYSICS TODAY LA English DT Article C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Stat Res Ctr, Amer Inst Phys, College Pk, MD USA. RP Kirby, K (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD APR PY 2001 VL 54 IS 4 SI SI BP 36 EP 41 DI 10.1063/1.1372112 PG 6 WC Physics, Multidisciplinary SC Physics GA 417QA UT WOS:000167844600017 ER PT J AU Schmidt, G Stuntz, S Zotz, G AF Schmidt, G Stuntz, S Zotz, G TI Plant size: an ignored parameter in epiphyte ecophysiology? SO PLANT ECOLOGY LA English DT Article; Proceedings Paper CT Meeting of the European-Science-Foundation Canopy Research Programme CY 1998 CL ST ANNES COLL, OXFORD, ENGLAND SP European Sci Fdn HO ST ANNES COLL DE allometry; inter-/intraspecific variability; nitrogen; photosynthetic capacity ID CRASSULACEAN ACID METABOLISM; HABITAT PREFERENCE; DIMERANDRA-EMARGINATA; VASCULAR EPIPHYTES; WATER RELATIONS; CARBON BALANCE; LIFE-FORMS; BROMELIACEAE; CAM; PHOTOSYNTHESIS AB A central objective of many ecophysiological investigations is the establishment of mechanistic explanations for plant distributions in time and space. The important, albeit mostly ignored, question arises as to the nature of the organisms that should be used as representative in pertinent experiments. We suggest that it is essential to use a 'demographic approach' in physiological ecology, because physiological parameters such as photosynthetic capacity (PC, determined under non-limiting conditions with the oxygen electrode) may change considerably with plant size. A survey of ten vascular epiphyte species from Central Panama revealed an up to fivefold continuous increase in PC from small to large conspecifics. Moreover, the intraspecific variation in PC was almost always higher than the interspecific variation when comparing only large individuals. Theoretical considerations and additional evidence from other ecophysiological experiments corroborate the conclusion that size must be taken into account in the design of ecophysiological experiments with vascular epiphytes. In the past, most studies have ignored plant size, which may now lead to complications in the hitherto unambiguous interpretation of their results. C1 Univ Wurzburg, Lehrstuhl Bot 2, D-97082 Wurzburg, Germany. Smithsonian Trop Res Inst, Balboa, Panama. RP Schmidt, G (reprint author), Univ Wurzburg, Lehrstuhl Bot 2, D-97082 Wurzburg, Germany. NR 31 TC 26 Z9 27 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1385-0237 J9 PLANT ECOL JI Plant Ecol. PD APR PY 2001 VL 153 IS 1-2 BP 65 EP 72 DI 10.1023/A:1017521204284 PG 8 WC Plant Sciences; Ecology; Forestry SC Plant Sciences; Environmental Sciences & Ecology; Forestry GA 471TA UT WOS:000170943700007 ER PT J AU Basset, Y AF Basset, Y TI Invertebrates in the canopy of tropical rain forests - How much do we really know? SO PLANT ECOLOGY LA English DT Article; Proceedings Paper CT Meeting of the European-Science-Foundation Canopy Research Programme CY 1998 CL ST ANNES COLL, OXFORD, ENGLAND SP European Sci Fdn HO ST ANNES COLL DE biodiversity; biogeography; collecting methods; conservation; predator-prey relationships; species richness ID PAPUA-NEW-GUINEA; VERTICAL-DISTRIBUTION; SOUTHERN CAMEROON; INSECT HERBIVORES; SPECIES-DIVERSITY; ARTHROPOD FAUNA; FLYING INSECTS; COSTA-RICA; ANT FAUNA; COMMUNITIES AB The current state of knowledge of canopy invertebrates in tropical rain forests is reviewed using data drawn, without bias toward taxon, collecting method or biogeographical region, from 89 studies concerned with mass-collecting (> 1000 individuals). The review is intended to identify the most serious gaps and biases in the distribution of higher taxa among forest types and biogeographical regions. With respect to knowledge, biogeographical regions can be ranked as Neotropical > Australian > Oriental > Afrotropical. The canopy of lowland wet and subtropical forests has been studied in greater detail, whereas the canopy of lowland dry and montane forests is much less well known. Collecting techniques influence greatly the present knowledge of canopy invertebrates. Invertebrates other than arthropods, often abundant in epiphytic habitats, phytotelmata and perched litter, are virtually unknown. The abundance of several groups, such as Acari, Collembola and Isoptera, is almost certainly seriously underestimated. Densities of invertebrate individuals in the canopy of tropical rain forests appear to be lower than in temperate forests, although invertebrate abundance is dissipated by the high standing-biomass of rain forests. Coleoptera, particularly Staphylinidae, Curculionidae and Chrysomelidae, along with Hymenoptera, Lepidoptera and Araneae appear to be the most speciose taxa in the canopy, and it is probable that this reflects their range of feeding habits and exploitation of rain forests habitats. The distribution of individuals among the major arthropod orders and across the studies examined is complex and depends on many factors. The amount of variance that can be directly explained by biogeography, forest types (subtropical, wet, dry or montane), or collecting methods appears to be about 11%. The explained variance increases when considering major families of Coleoptera (28%) or subfamilies of Chrysomelidae (40%). In all cases, the variance explained by the type of forest is much higher than by that explained by biogeography. These conclusions are similar when considering various prey-predator relationships in the canopy. This suggests that, at the higher taxa level, the composition of the invertebrate fauna in the canopy may vary comparatively more across forest types than across biogeographical regions and this is discussed briefly from a conservation viewpoint. C1 Smithsonian Trop Res Inst, Balboa, Ancon, Panama. RP Basset, Y (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Ancon, Panama. EM bassety@tivoli.si.edu RI Basset, Yves/B-6642-2014 NR 158 TC 74 Z9 86 U1 3 U2 32 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1385-0237 EI 1573-5052 J9 PLANT ECOL JI Plant Ecol. PD APR PY 2001 VL 153 IS 1-2 BP 87 EP 107 DI 10.1023/A:1017581406101 PG 21 WC Plant Sciences; Ecology; Forestry SC Plant Sciences; Environmental Sciences & Ecology; Forestry GA 471TA UT WOS:000170943700009 ER PT J AU Kalko, EKV Handley, CO AF Kalko, EKV Handley, CO TI Neotropical bats in the canopy: diversity, community structure, and implications for conservation SO PLANT ECOLOGY LA English DT Article; Proceedings Paper CT Meeting of the European-Science-Foundation Canopy Research Programme CY 1998 CL ST ANNES COLL, OXFORD, ENGLAND SP European Sci Fdn HO ST ANNES COLL DE Brazil; Chiroptera; guild; inventory methods; mistnetting; vertical stratification ID DIPTEROCARP RAIN-FOREST; FRENCH-GUIANA; ECHOLOCATION CALLS; FORAGING BEHAVIOR; INSECTIVOROUS BATS; SPECIES-DIVERSITY; SOUTHERN AFRICA; EATING BATS; FRUIT BATS; PHYLLOSTOMIDAE AB We compare results of parallel ground and canopy netting of bats (Microchiroptera) in three adjacent forest sites near Belem, Brazil, to document possible differences in vertical distribution of species. We caught 1871 individuals representing 49 species of three families (Emballonuridae, Phyllostomidae, Vespertilionidae). Capture effort, totaling 1955.5 mistnet hours in several cycles over a two-year period, was similar for ground and canopy nets. The canopy rigs yielded more species (n = 41) than the ground nets (n = 35), but both samples were characterized by rank abundance curves with similar shape and with a dominance of frugivores (Phyllostomidae). Nearly half (n = 24) of the species were captured in numbers too small (n < 6) to allow firm classification, but differences in capture frequencies of some of the better-sampled species in high and low nets reveal vertical stratification. Species-specific differences in diet, foraging strategies, roost sites, and sampling bias contribute to this pattern. As a result of the differential use of space among bats, alterations of forest structure are likely to result in changes in structure and function of local bat communities, but our limited knowledge of natural history and ecology of many species limits definition of changes. We see a critical need for further research into the extent to which habitat complexity influences species richness and abundance of bats. This information is especially important in view of the need to develop and apply conservation-oriented programs to maintain biodiversity. A review of recent improvements in techniques for inventorying bats shows that a combination of methods, including mistnetting and acoustic monitoring, is mandatory for such studies. C1 Univ Ulm, Dept Expt Ecol Bio 3, D-89069 Ulm, Germany. Natl Museum Nat Hist, Washington, DC 20560 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Kalko, EKV (reprint author), Univ Ulm, Dept Expt Ecol Bio 3, Albert Einstein Allee 11, D-89069 Ulm, Germany. NR 87 TC 103 Z9 127 U1 3 U2 41 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1385-0237 J9 PLANT ECOL JI Plant Ecol. PD APR PY 2001 VL 153 IS 1-2 BP 319 EP 333 DI 10.1023/A:1017590007861 PG 15 WC Plant Sciences; Ecology; Forestry SC Plant Sciences; Environmental Sciences & Ecology; Forestry GA 471TA UT WOS:000170943700027 ER PT J AU Gehrig, H Gaussmann, O Marx, H Schwarzott, D Kluge, M AF Gehrig, H Gaussmann, O Marx, H Schwarzott, D Kluge, M TI Molecular phylogeny of the genus Kalanchoe (Crassulaceae) inferred from nucleotide sequences of the ITS-1 and ITS-2 regions SO PLANT SCIENCE LA English DT Article DE Crassulacean acid metabolism (CAM); ecophysiology; Internal Transcribed Spacer (ITS); Kalanchoe; Madagascar; molecular phylogeny ID ACID METABOLISM; DNA POLYMORPHISMS; MADAGASCAR AB The study presents an analysis of genotypic diversity in the genus Kalanchoe (Crassulaceae) on the level of Internal Transcribed Spacer (ITS) sequences and the attempt to correlate this diversity with previous findings on ecophysiological behavior, habitat preference. infrageneric taxonomic position of the species and DNA polymorphism derived from RAPD-PCR data. The Kalanchoe species are mainly abundant in Madagascar and eastern continental Africa and perform in situ diverse modes of crassulacean acid metabolism (CAM), an ecophysiologically relevant adaptation of photosynthesis. Total DNA was extracted from 68 kalanchoe species and varieties. The ITS-1 and ITS-2 regions of the nuclear RNA genes were amplified by polymerase chain reaction, cloned and sequenced. The alignments of the sequences were evaluated by distance (neighbor joining) and character state (maximum parsimony) methods. The main topologies of the obtained ITS phylogenetic trees were quite similar irrespective of the mode of evaluation and show: (A) within the Crassulaceae the genus Kalanchoe forms a monophyletic clade: and (B) within the genus the species form three main clusters which coincide well with the previously reported three infrageneric sections of the species distinguishable by classical taxonomic criteria, the mode of in situ CAM performance, and DNA fragment pattern obtained by RAPD-PCR analyses. Moreover, the ITS phylogenetic trees show that all African Kalanchoe species form a distinct group within the most derived of the three main clusters. This is consistent with the view that the center of phylogenetic radiation of the genus is located in Madagascar from where the species have spread into the continental Africa. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved. C1 Smithsonian Trop Res Inst, Unit 0948, APO 340020948, AA, Panama. Darmstadt Univ Technol, D-64287 Darmstadt, Germany. RP Gehrig, H (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO 340020948, AA, Panama. NR 24 TC 29 Z9 35 U1 2 U2 20 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0168-9452 J9 PLANT SCI JI Plant Sci. PD APR PY 2001 VL 160 IS 5 BP 827 EP 835 DI 10.1016/S0168-9452(00)00447-7 PG 9 WC Biochemistry & Molecular Biology; Plant Sciences SC Biochemistry & Molecular Biology; Plant Sciences GA 425VL UT WOS:000168312300006 ER PT J AU Roubik, DW Wolda, H AF Roubik, DW Wolda, H TI Do competing honey bees matter? Dynamics and abundance of native bees before and after honey bee invasion SO POPULATION ECOLOGY LA English DT Article DE African Apis; impact studies; neotropical bees ID AFRICANIZED HONEYBEES; TROPICAL FOREST; APIS-MELLIFERA; STINGLESS BEES; POLLINATORS; IMPACT; HYMENOPTERA; ECOSYSTEMS; COMMUNITY; APIDAE AB To provide replicate samples of local bee populations in a nature preserve, Light traps operated continuously on Barro Colorado Island (BCI), Panama, collected bees for 17 years, including 10 years following invasion by African Apis mellifera. Honey bees appeared in light traps as the first swarms colonized the Panama Canal area. Their numbers followed seasonal trends shown in independent studies, thus indicating bee abundance and activity in a large area. No measurable population-level impact of competition between this invading honey bee and native bees, despite many demonstrations of resource competition at flower patch and colony levels, changed annual abundances of all 15 native bee species. Native bee abundance did not decrease, nor did native bees show substantial reciprocal yearly change with honey bee abundance. One strong negative correlation of bee catches with an extremely rainy year was found. However, multiple regression using rainfall and honey bee abundance as the independent variables showed that neither was responsible for bee population change over 17 years. Nearly half the native species declined during a year that displayed peak honey bee number. That competition from honey bees on an island the size of BCI was necessarily reduced below impact levels expected on the mainland is discussed using a model of resource and consumer density, foraging range, and island size. C1 Smithsonian Inst, Smithsonian Trop Res Inst, Washington, DC 20560 USA. RP Roubik, DW (reprint author), Smithsonian Inst, Smithsonian Trop Res Inst, Washington, DC 20560 USA. NR 59 TC 55 Z9 62 U1 5 U2 54 PU SPRINGER-VERLAG TOKYO PI TOKYO PA 3-3-13, HONGO, BUNKYO-KU, TOKYO, 113, JAPAN SN 1438-3896 J9 POPUL ECOL JI Popul. Ecol. PD APR PY 2001 VL 43 IS 1 BP 53 EP 62 DI 10.1007/PL00012016 PG 10 WC Ecology SC Environmental Sciences & Ecology GA 439YN UT WOS:000169145300008 ER PT J AU Sakai, S AF Sakai, S TI Phenological diversity in tropical forests SO POPULATION ECOLOGY LA English DT Review DE plant reproductive phenology; general flowering; pollination; predator satiation; resource availability; phylogenetic constraint ID LOWLAND DIPTEROCARP FOREST; MAST-FRUITING DIPTEROCARPACEAE; LEAF LIFE-SPAN; RAIN-FOREST; REPRODUCTIVE PHENOLOGY; COSTA-RICA; FLOWERING PHENOLOGIES; ASEASONAL TROPICS; SEED PRODUCTION; DRY FOREST AB One of the most intriguing and complex characteristics of reproductive phenology in tropical forests is high diversity within and among forests. To understand such diversity, Newstrom et al. provided a systematic framework for the classification of tropical flowering phenology. They adopted frequency and regularity as criteria with priority, and classified plants in La Selva, Costa Rica, where most plants reproduced more than once a year irregularly. Many other studies have demonstrated annual cycles corresponding to rainfall patterns at the community level in Neotropical forests, including La Selva. On the other hand, supraannual flowering synchronized among various plant species, called general flowering, is known from aseasonal lowland dipterocarp forests in Southeast Asia. Within both forests, a wide spectrum of flowering patterns is found. This range of patterns suggests the great potential of tropical phenological studies to explore the selective pressures on phenology. Various abiotic and biotic factors can be selective agents. The shared pollinators hypothesis suggests that plant species sharing pollinators segregate flowering temporarily to minimize interspecific overlap in flowering times and thus minimize ineffective pollination or competition for pollinators, indicating strong phylogenetic constraints in timing and variation of flowering. Comparison of phenology within and among forests may help our understanding of phenological diversity. Attempts are now being made to develop a common language to communicate concepts and render interpretations of data more compatible among investigators and to create a network to promote comparative studies. C1 Smithsonian Trop Res Inst, Ancon, Panama. RP Sakai, S (reprint author), Kyoto Univ, Grad Sch Human & Environm Studies, Sakyo Ku, Yoshida Nihonmatsu Cho, Kyoto 6068501, Japan. NR 117 TC 64 Z9 70 U1 5 U2 42 PU SPRINGER-VERLAG TOKYO PI TOKYO PA 3-3-13, HONGO, BUNKYO-KU, TOKYO, 113, JAPAN SN 1438-3896 J9 POPUL ECOL JI Popul. Ecol. PD APR PY 2001 VL 43 IS 1 BP 77 EP 86 DI 10.1007/PL00012018 PG 10 WC Ecology SC Environmental Sciences & Ecology GA 439YN UT WOS:000169145300010 ER PT J AU Krombein, KV Norden, BB AF Krombein, KV Norden, BB TI Notes on trap-nesting Sri Lankan wasps and bees (Hymenoptera : Vespidae, Pompilidae, Sphecidae, Colletidae, Megachtlidae) SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE Sri Lanka; trap-nest; stem-nesting; Hymenoptera; Vespidae; Pompilidae; Sphecidae; Colletidae; Megachilidae AB A trap-nesting study was conducted in Kandy, Sri Lanka, during February to June 1997. Wooden pieces ca. 17 cm long with central grooves of either 3 or 5 mm in diameter were placed outside our residence, providing nesting sites for stem-nesting Hymenoptera. A diversity of solitary wasps and bees, including two new species of Anthidiellum, were found nesting in these "artificial stems." Evidence of supersedure was noted, and we give the first report of a probable new subgenus of Hylaeus that uses a mixture of resin and sand for cell construction. Notes on nest architecture are provided for the observed trap-nesters belonging to the families Vespidae, Pompilidae, Sphecidae, Colletidae, and Megachilidae. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, Washington, DC 20560 USA. RP Krombein, KV (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, Washington, DC 20560 USA. NR 5 TC 1 Z9 1 U1 1 U2 8 PU ENTOMOL SOC WASHINGTON PI WASHINGTON PA SMITHSONIAN INSTITUTION DEPT ENTOMOLOGY, WASHINGTON, DC 20560 USA SN 0013-8797 J9 P ENTOMOL SOC WASH JI Proc. Entomol. Soc. Wash. PD APR PY 2001 VL 103 IS 2 BP 274 EP 281 PG 8 WC Entomology SC Entomology GA 417LP UT WOS:000167836700003 ER PT J AU Davis, DR AF Davis, DR TI A new species of Prototheora from Malawi, with additional notes on the distribution and morphology of the genus (Lepidoptera : Prototheoridae) SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE Africa; biogeography; Hepialoidea; South Africa AB A new species, Prototheora malawiensis, of the endemic southern African family Prototheoridae is described and illustrated from the Mulanje Massif of Malawi. This constitutes only the second species to be collected outside of South Africa, the first being Prototheora angolae Davis from Angola. Also noted are additional collecting records for Prototheora cooperi Janse, P. corvifera (Meyrick), P. petrosema Meyrick, P. quadricornis Meyrick, and the first record from Cape Province, South Africa, of Prototheora parachlora Meyrick. C1 Smithsonian Inst, Dept Entomol, Natl Museum Nat Hist, Washington, DC 20560 USA. RP Davis, DR (reprint author), Smithsonian Inst, Dept Entomol, Natl Museum Nat Hist, Washington, DC 20560 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU ENTOMOL SOC WASHINGTON PI WASHINGTON PA SMITHSONIAN INSTITUTION DEPT ENTOMOLOGY, WASHINGTON, DC 20560 USA SN 0013-8797 J9 P ENTOMOL SOC WASH JI Proc. Entomol. Soc. Wash. PD APR PY 2001 VL 103 IS 2 BP 452 EP 456 PG 5 WC Entomology SC Entomology GA 417LP UT WOS:000167836700027 ER PT J AU Geller, MJ AF Geller, MJ TI The unexplored redshift survey SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Editorial Material ID SURFACE-BRIGHTNESS GALAXIES; STAR-FORMATION; SKY SURVEY; UNIVERSE AB Redshift surveys remain an important constraint on cosmological parameters and a key to characterizing the nature and evolution of the large-scale distribution of galaxies. I discuss redshift surveys as a route to exploration of other issues associated with large-scale structure including the low surface brightness universe and the links between star formation and the galaxy distribution. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6280 EI 1538-3873 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD APR PY 2001 VL 113 IS 782 BP 405 EP 408 DI 10.1086/319534 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 420HF UT WOS:000167999000001 ER PT J AU Montali, RJ Mikota, SK Cheng, LI AF Montali, RJ Mikota, SK Cheng, LI TI Mycobacterium tuberculosis in zoo and wildlife species SO REVUE SCIENTIFIQUE ET TECHNIQUE DE L OFFICE INTERNATIONAL DES EPIZOOTIES LA English DT Article DE animal diseases; mycobacteria; Mycobacterium tuberculosis; tuberculosis; wildlife; zoo animals; zoonoses ID PUBLIC-HEALTH IMPLICATIONS; INFECTION; ELEPHANTS; ANIMALS; COMPLEX; COLONY; SEALS; BOVIS AB Tuberculosis caused by Mycobacterium tuberculosis and M. tuberculosis-like organisms has been identified in a wide range of species, including non-human primates, elephants and other exotic ungulates, carnivores, marine mammals and psittacine birds. Disease associated with M. tuberculosis has occurred mostly within captive settings and does not appear to occur naturally in free-living mammals. Mycobacterium tuberculosis probably originated as an infection of humans, but from the zoonotic standpoint, non-human primates, Asian elephants and psittacine birds have the potential to transmit this disease to humans. However, the overall prevalence of disease in these susceptible species is low and documented transmissions of M. tuberculosis between animals and humans are uncommon. Mycobacterium tuberculosis causes progressive pulmonary disease in mammals and a muco-cutaneous disease in parrots. In all cases, the disease can disseminate and be shed into the environment. Diagnosis in living animals is biased on intradermal tuberculin testing in non-human primates, culturing trunk secretions in elephants, and biopsy and culture of external lesions in parrots. Ancillary testing with deoxyribonucleic acid probes and nucleic acid amplification, and enzyme-linked immunosorbent assays have been adapted to some of these species with promising results. Additionally, new guidelines for controlling tuberculosis in elephants in the United States of America, and programmes for tuberculosis prevention in animal handlers have been established. C1 Smithsonian Natl Zool Pk, Dept Pathol, Washington, DC 20008 USA. Audubon Ctr Res Endangered Species, New Orleans, LA 70131 USA. RP Montali, RJ (reprint author), Smithsonian Natl Zool Pk, Dept Pathol, 3001 Connecticut Ave NW, Washington, DC 20008 USA. NR 78 TC 92 Z9 94 U1 1 U2 26 PU OFFICE INT EPIZOOTIES PI PARIS PA 12 RUE DE PRONY, 75017 PARIS, FRANCE SN 0253-1933 J9 REV SCI TECH OIE JI Rev. Sci. Tech. Off. Int. Epizoot. PD APR PY 2001 VL 20 IS 1 BP 291 EP 303 PG 13 WC Veterinary Sciences SC Veterinary Sciences GA 415FX UT WOS:000167711200015 PM 11288517 ER PT J AU Funk, VA Robinson, H AF Funk, VA Robinson, H TI A bully new genus from the Andes (Compositae : Liabeae) SO SYSTEMATIC BOTANY LA English DT Article AB Dillandia (Compositae, Liabeae) is described as new on the basis of three species: D. perfoliata (S. E Blake) V. A. Funk and Fl. Rob. (= Liabum perfoliatum), D. chachapoyensis (H. Rob.) V. A. Funk and Fl. Rob. (=Munnozia charhapoyensis), and D. subumbellata V. A. Funk and H. Rob. Phylogenetic analysis of Liabeae using data from the nuclear ribosomal DNA internal transcribed spacer (Kim et al. unpublished data) places two of the Dillandia species outside the subtribe Munnoziinae and separates them from all other clades in the tribe as well. Irregular spine groupings on the pollen confirm the separation of these species from the Munnoziinae. Morphological analysis suggests that these two and one additional species form a monophyletic group defined by their possession of bullate leaf surfaces and pale anther thecae. This study is an example of how molecular and morphological data, when used together, can lead to a better classification. C1 Smithsonian Inst, US Natl Herbarium, Washington, DC 20560 USA. RP Funk, VA (reprint author), Smithsonian Inst, US Natl Herbarium, Washington, DC 20560 USA. NR 13 TC 8 Z9 9 U1 0 U2 0 PU AMER SOC PLANT TAXONOMISTS PI BRONX PA NEW YORK BOTANICAL GARDEN, BRONX, NY 10458-5126 USA SN 0363-6445 J9 SYST BOT JI Syst. Bot. PD APR-JUN PY 2001 VL 26 IS 2 BP 216 EP 225 PG 10 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA 442GH UT WOS:000169276500003 ER PT J AU Kress, WJ Larsen, K AF Kress, WJ Larsen, K TI Smithatris, a new genus of Zingiberaceae from southeast Asia SO SYSTEMATIC BOTANY LA English DT Article ID BORNEO AB Smithatris supraneanae W. J. Kress & K. Larsen, gen. et sp. nov. is described and illustrated. The new taxon was first collected in the limestone hills in the Saraburi Province north of Bangkok, Thailand, and probably ranges into adjacent Burma as well. Smithatris is most closely allied with several genera in the tribe Hedychieae including Curcuma, Stahlianthus, and Hitchenia. It most closely resembles the latter genus sharing the petiolate leaves and long pedunculate inflorescence with congested, pouched bracts, but differing in the deeply split labellum and hood-like structure formed by the lateral staminodes and dorsal corolla lobe that partially encloses the anther. In a separate analysis of the phylogenetic relationships of the genera of the Zingiberaceae based on molecular sequence data, Smithatris forms a nested assemblage with the above three genera thereby supporting recognition of this new taxon at the generic level. Smithatris is commonly used in ceremonies during the Buddhist lent, is sold as a cut flower in local markets in Saraburi, Thailand, and recently has become widespread in commercial nurseries. The fact that this ethnobotanically important plant has remained unknown to taxonomists until now suggests that our knowledge of the flora of tropical Asia is still rudimentary. C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Bot, Washington, DC 20560 USA. Aarhus Univ, Dept Syst Bot, DK-8240 Risskov, Denmark. RP Kress, WJ (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Bot, MRC-166, Washington, DC 20560 USA. NR 9 TC 10 Z9 11 U1 1 U2 2 PU AMER SOC PLANT TAXONOMISTS PI BRONX PA NEW YORK BOTANICAL GARDEN, BRONX, NY 10458-5126 USA SN 0363-6445 J9 SYST BOT JI Syst. Bot. PD APR-JUN PY 2001 VL 26 IS 2 BP 226 EP 230 PG 5 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA 442GH UT WOS:000169276500004 ER PT J AU Roalson, EH Columbus, JT Friar, EA AF Roalson, EH Columbus, JT Friar, EA TI Phylogenetic relationships in cariceae (Cyperaceae) based on ITS (nrDNA) and trnT-L-F (cpDNA) region sequences: Assessment of subgeneric and sectional relationships in Carex with emphasis on section Acrocystis SO SYSTEMATIC BOTANY LA English DT Article ID NUCLEAR RIBOSOMAL DNA; CHLOROPLAST DNA; GENUS CAREX; CLASSIFICATION; INCONGRUENCE; SYSTEMATICS; CONFIDENCE; EVOLUTION; POSITION; GENERA AB With approximately 2,000 species, Carex is the largest genus in the Cyperaceae and is one of the most widespread genera in the world. Relationships within Carer and among the genera of the Cariceae (Carex, Cymophyllus, Kobresia, Schoenoxiphium, and Uncinia) are unclear. For this reason, a molecular phylogenetic study employing nrDNA ITS and cpDNA trnT-L-F spacer sequences was undertaken. In addition to creating hypotheses of relationship for the Cariceae and testing classifications of this tribe, a primary goal of this study was to assess relationships within Carer section Acrocystis and identify a monophyletic group for more detailed study. These analyses suggest that Cymophyllus, Kobresia, Schoenoxiphium, and Uncinia are nested within Care x. Three primary clades are suggested: a Carer subgenus Vignea clade. a clade including Carer subgenus Primocarex (for the most part) and the other genera of Cariceae, and a clade predominately comprised of Carer subgenera Carer and Indocarex. A large part of Carer section Acrocystis forms a monophyletic group but several Eurasian species are more closely related to other groups rather than to this core clade. Assessment of chromosome number variation across the Cariceae clade suggests that the ancestor of the Cariceae had a moderate to high chromosome number. In addition, these analyses suggest the sister group of the Cariceae is a clade including Scirpus sensu stricto, Amphiscirpus, and Dulichium. C1 Rancho Santa Ana Bot Garden, Claremont, CA 91711 USA. RP Roalson, EH (reprint author), Smithsonian Inst, LMS, MSC, MRC534,4210 Silver Hill Rd, Suitland, MD 20746 USA. RI Molina, Ana/F-6475-2010 OI Molina, Ana/0000-0002-8958-7033 NR 58 TC 81 Z9 100 U1 1 U2 9 PU AMER SOC PLANT TAXONOMISTS PI BRONX PA NEW YORK BOTANICAL GARDEN, BRONX, NY 10458-5126 USA SN 0363-6445 J9 SYST BOT JI Syst. Bot. PD APR-JUN PY 2001 VL 26 IS 2 BP 318 EP 341 PG 24 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA 442GH UT WOS:000169276500011 ER PT J AU Ryan, MJ Phelps, SM Rand, AS AF Ryan, MJ Phelps, SM Rand, AS TI How evolutionary history shapes recognition mechanisms SO TRENDS IN COGNITIVE SCIENCES LA English DT Editorial Material ID FEMALE TUNGARA FROGS; PHYSALAEMUS-PUSTULOSUS; SEXUAL SELECTION; MATE-QUALITY; RESPONSES; BIASES; CALLS AB Evolutionary psychologists have emphasized the importance of natural selection in shaping cognitive functions, but historical contingency has not received direct study. This is crucial because in response to selection, complex traits tend to be fins-tuned or jury-rigged rather than totally reconstructed. We hypothesize that the neural and cognitive strategies an animal employs in signal recognition are influenced by the strategies used by its ancestors. The responses of female tungara frogs to ancestral calls and to calls of other closely related species are influenced by history. By training artificial neural networks with a series of calls that mimic the species' past history of call evolution or various control histories, we have shown that only networks that evolved through the mimetic history predict the response biases of tungara frogs. C1 Univ Texas, Sect Integrat Biol C0930, Austin, TX 78712 USA. Emory Univ, Ctr Behav Neurosci, Atlanta, GA 30329 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Ryan, MJ (reprint author), Univ Texas, Sect Integrat Biol C0930, Austin, TX 78712 USA. NR 40 TC 30 Z9 30 U1 0 U2 7 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 1364-6613 J9 TRENDS COGN SCI JI TRENDS COGN. SCI. PD APR PY 2001 VL 5 IS 4 BP 143 EP 148 DI 10.1016/S1364-6613(00)01616-8 PG 6 WC Behavioral Sciences; Neurosciences; Psychology, Experimental SC Behavioral Sciences; Neurosciences & Neurology; Psychology GA 420CJ UT WOS:000167986100007 ER PT J AU Petit, RE AF Petit, RE TI A note on Lucina multilineata "Tuomey and Holmes" (Bivalvia : Lucinidae) SO NAUTILUS LA English DT Article C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Petit, RE (reprint author), 806 St Charles Rd, N Myrtle Beach, SC 29852 USA. NR 13 TC 1 Z9 2 U1 0 U2 0 PU BAILEY-MATTHEWS SHELL MUSEUM PI SANIBEL PA C/O DR JOSE H LEAL, ASSOCIATE/MANAGING EDITOR, 3075 SANIBEL-CAPTIVA RD, SANIBEL, FL 33957 USA SN 0028-1344 J9 NAUTILUS JI Nautilus PD MAR 31 PY 2001 VL 115 IS 1 BP 35 EP 36 PG 2 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 419JH UT WOS:000167945200005 ER PT J AU Springel, V Yoshida, N White, SDM AF Springel, V Yoshida, N White, SDM TI GADGET: a code for collisionless and gasdynamical cosmological simulations SO NEW ASTRONOMY LA English DT Article DE methods : numerical; galaxies : interactions; dark matter ID SMOOTHED PARTICLE HYDRODYNAMICS; N-BODY SIMULATIONS; SPECIAL-PURPOSE COMPUTER; DARK-MATTER HALOS; TREE-CODE; GALAXY FORMATION; PARALLEL COMPUTER; GRAVITY SOLVER; ERROR ANALYSIS; TIDAL TAILS AB We describe the newly written code GADGET which is suitable both for cosmological simulations of structure formation and for the simulation of interacting galaxies. GADGET evolves self-gravitating collisionless fluids with the traditional N-body approach, and a collisional gas by smoothed particle hydrodynamics. Along with the serial version of the code, we discuss a parallel version that has been designed to run on massively parallel supercomputers with distributed memory. While both versions use a tree algorithm to compute gravitational forces, the serial version of GADGET can optionally employ the special-purpose hardware GRAPE instead of the tree. Periodic boundary conditions are supported by means of an Ewald summation technique. The code uses individual and adaptive timesteps for all particles, and it combines this with a scheme for dynamic tree updates. Due to its Lagrangian nature, GADGET thus allows a very large dynamic range to be bridged, both in space and time. So far, GADGET has been successfully used to run simulations with up to 7.5 x 10(7) particles, including cosmological studies of large-scale structure formation, high-resolution simulations of the formation of clusters of galaxies, as well as workstation-sized problems of interacting galaxies. In this study, we detail the numerical algorithms employed, and show various tests of the code. We publicly release both the serial and the massively parallel version of the code. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Max Planck Inst Astrophys, D-85740 Munich, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Springel, V (reprint author), Max Planck Inst Astrophys, Karl Schwarzschild Str 1, D-85740 Munich, Germany. RI Yoshida, Naoki/A-4305-2011; OI Springel, Volker/0000-0001-5976-4599 NR 98 TC 982 Z9 987 U1 2 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1384-1092 J9 NEW ASTRON JI New Astron. PD MAR 28 PY 2001 VL 6 IS 2 BP 79 EP 117 DI 10.1016/S1384-1076(01)00042-2 PG 39 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 432TC UT WOS:000168710900003 ER PT J AU Milne, GA Davis, JL Mitrovica, JX Scherneck, HG Johansson, JM Vermeer, M Koivula, H AF Milne, GA Davis, JL Mitrovica, JX Scherneck, HG Johansson, JM Vermeer, M Koivula, H TI Space-geodetic constraints on glacial isostatic adjustment in Fennoscandia SO SCIENCE LA English DT Article ID SEA-LEVEL CHANGE; COMPUTING 3-DIMENSIONAL DEFORMATIONS; PLEISTOCENE DEGLACIATION; SPECTRAL FORMALISM; NORTH-AMERICA; SURFACE LOADS; RISE; VISCOSITY; RECORDS; MANTLE AB Analysis of Global Positioning System (GPS) data demonstrates that ongoing three-dimensional crustal deformation in Fennoscandia is dominated by glacial isostatic adjustment. Our comparison of these CPS observations with numerical predictions yields an Earth model that satisfies independent geologic constraints and bounds both the average viscosity in the upper mantle (5 x 10(20) to 1 X 10(21) pascal seconds) and the elastic thickness of the Lithosphere (90 to 170 kilometers), We combined GPS-derived radial motions with Fennoscandian tide gauge records to estimate a regional sea surface rise of 2.1 +/- 0.3 mm/year. furthermore, ongoing horizontal tectonic motions greater than similar to1 mm/year are ruled out on the basis of the CPS-derived three-dimensional crustal velocity field. C1 Univ Durham, Dept Geol Sci, Durham DH1 3LE, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Chalmers, Onsala Space Observ, SE-43992 Onsala, Sweden. Finnish Geodet Inst, FI-02431 Masala, Finland. RP Milne, GA (reprint author), Univ Durham, Dept Geol Sci, Durham DH1 3LE, England. EM g.a.milne@durham.ac.uk RI Davis, James/D-8766-2013; Vermeer, Martin/G-2468-2013 OI Davis, James/0000-0003-3057-477X; Vermeer, Martin/0000-0003-3107-6342 NR 40 TC 218 Z9 219 U1 2 U2 18 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 MAR 23 PY 2001 VL 291 IS 5512 BP 2381 EP 2385 DI 10.1126/science.1057022 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 413UH UT WOS:000167618700047 PM 11264528 ER PT J AU Balakrishnan, N Dalgarno, A AF Balakrishnan, N Dalgarno, A TI On the quenching of rovibrationally excited molecular oxygen at ultracold temperatures SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID POTENTIAL-ENERGY SURFACE; VIBRATIONAL-RELAXATION; COLLISIONAL ALIGNMENT; SUPERSONIC EXPANSIONS; AB-INITIO; SCATTERING; PHOTOASSOCIATION; O-2; HE-O-2; ATOMS AB We report quantum mechanical scattering calculations of zero temperature quenching rate coefficients for vibrationally and rotationally excited O-2 in collisions with He-3. It is found that vibrational energy is channeled into more specific rotational levels in the ultracold regime than at thermal energies where a broad range of rotational levels are populated. The influence of the van der Waals interaction on the low-temperature quenching rate coefficients and the possibility of trapping vibrationally excited O-2 by the buffer gas cooling technique are also discussed. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Balakrishnan, N (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 40 TC 34 Z9 35 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 22 PY 2001 VL 105 IS 11 BP 2348 EP 2351 DI 10.1021/jp0034224 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 413VN UT WOS:000167632400029 ER PT J AU Li, QJ Xu, ZF Kress, WJ Xia, YM Zhang, L Deng, XB Gao, JY Bai, ZL AF Li, QJ Xu, ZF Kress, WJ Xia, YM Zhang, L Deng, XB Gao, JY Bai, ZL TI Pollination - Flexible style that encourages outcrossing SO NATURE LA English DT Article C1 Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Mengla 666303, Yunnan, Peoples R China. Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, Washington, DC 20560 USA. Chinese Acad Sci, Kunming Inst Bot, Kunming 650204, Yunnan, Peoples R China. RP Li, QJ (reprint author), Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Mengla 666303, Yunnan, Peoples R China. NR 9 TC 68 Z9 109 U1 1 U2 20 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAR 22 PY 2001 VL 410 IS 6827 BP 432 EP 432 DI 10.1038/35068635 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 412YX UT WOS:000167583800031 PM 11260703 ER PT J AU Zheng, XW Zhang, QZ Ho, PTP Pratap, P AF Zheng, XW Zhang, QZ Ho, PTP Pratap, P TI Multifield mosaic of the NGC 7538 region SO ASTROPHYSICAL JOURNAL LA English DT Article DE HII regions; ISM : clouds; ISM : individual (NGC 7538); ISM : kinematics and dynamics; masers; stars : formation ID H-II REGIONS; MOLECULAR CLOUD; YOUNG STARS; OUTFLOWS; ORION; CO; MASERS AB We present mosaics of six Very Large Array images made in the NH(3) (1, 1) and (2, 2) lines toward NGC 7538. Both the NH(3) (1, 1) and (2, 2) emissions show clumpy and filamentary structures. The dense clumps are found near water maser emission or near the youngest member of groups of infrared sources. At the edges of clumps, temperature enhancements indicate external heating possibly by the nearby H II regions. The outflows in this region are conspicuously located in the voids between the clumps. Because there is more mass in the dense clumps than in the outflows, we suggest that the dense medium shapes the outflows and channels the swept-up material to the low-density regions. C1 Nanjing Univ, Dept Astron, Nanjing 210093, Peoples R China. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. MIT, Haystack Observ, Westford, MA 01886 USA. RP Zheng, XW (reprint author), Nanjing Univ, Dept Astron, Nanjing 210093, Peoples R China. OI Zhang, Qizhou/0000-0003-2384-6589 NR 25 TC 20 Z9 20 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 MAR 20 PY 2001 VL 550 IS 1 BP 301 EP 313 DI 10.1086/319709 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 417YN UT WOS:000167863200028 ER PT J AU Di Matteo, T Johnstone, RM Allen, SW Fabian, AC AF Di Matteo, T Johnstone, RM Allen, SW Fabian, AC TI Accretion onto nearby supermassive black holes: Chandra constraints on the dominant cluster galaxy NGC 6166 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; X-ray : galaxies ID ELLIPTIC GALAXIES; RADIO GALAXIES; FLOWS; CONVECTION; MODEL AB Chandra observations of low-luminosity supermassive black holes in nearby elliptical galaxies provide tight limits on both their nuclear luminosities and their Bondi accretion rates. We examine Chandra constraints on NGC 6166, the dominant galaxy in the cluster Abell 2199, which hosts an similar to 10(9) M-., black hole. We measure a nuclear X-ray luminosity of L-X,L- 1 keV similar to 10(40) ergs s(-1) and show that the density and temperature profiles of the hot interstellar medium imply a Bondi accretion rate of (M) over dot(Bondi) less than or similar to 3 x 10(-2) M-. yr(-1). This accretion rate predicts a nuclear luminosity of similar to 10(44) ergs s(-1) for a canonical radiative efficiency of 10%. Unless the Bondi estimate is inappropriate and/or the accretion rate onto the black hole is significantly reduced, the observed nuclear flux constrains the radiative efficiency of the accretion flow to be eta similar to 10(-5). We show that low radiative efficiency accretion flows can explain the observed nuclear X-ray luminosity but that the power output from the jets in NGC 6166 is also important to the energetics of the system. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Di Matteo, T (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Di Matteo, Tiziana/O-4762-2014 OI Di Matteo, Tiziana/0000-0002-6462-5734 NR 25 TC 38 Z9 38 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2001 VL 550 IS 1 BP L19 EP L23 DI 10.1086/319489 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413GZ UT WOS:000167605400005 ER PT J AU Wilner, DJ De Pree, CG Welch, WJ Goss, WM AF Wilner, DJ De Pree, CG Welch, WJ Goss, WM TI Hot cores in W49N and the timescale for hot core evolution SO ASTROPHYSICAL JOURNAL LA English DT Article DE HII regions; ISM : individual (W49N); stars : formation ID RECOMBINATION LINE OBSERVATIONS; FORMING REGION W49A; H-II REGIONS; METHYL CYANIDE; CLOUD CORE; MASSIVE STARS; ORION; EMISSION; KINEMATICS AB We present subarcsecond resolution observations of the star-forming region W49N made with the Berkeley-Illinois-Maryland Association array at 1.4 mm wavelength in the continuum and CH3CN lines. The J = 12-11 continuum image, at a resolution of 0".18 (2000 AU), shows many of the previously identified ultracompact H II regions and at least one new source whose steep spectrum to short wavelengths indicates dust emission. This compact dust concentration also shows the strongest CH3CN emission in the region. Additional peaks of CH3CN emission likely mark hot cores produced by other deeply embedded young massive stars that may be precursors to O-type stars like those that power the ultracompact H II regions. The number ratio of hot cores to ultracompact H II regions found in W49N provides a measure of the relative timescales of these early evolutionary phases. Although the samples are small, the source counts suggest that the hot core lifetime is most likely shorter than, but comparable to, the ultracompact H II region lifetime. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Agnes Scott Coll, Dept Phys & Astron, Decatur, GA 30030 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. RP Wilner, DJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 29 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 MAR 20 PY 2001 VL 550 IS 1 BP L81 EP L85 DI 10.1086/319498 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413GZ UT WOS:000167605400018 ER PT J AU Spurr, RJD Kurosu, TP Chance, KV AF Spurr, RJD Kurosu, TP Chance, KV TI A linearized discrete ordinate radiative transfer model for atmospheric remote-sensing retrieval SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID OZONE PROFILES; TROPOSPHERIC OZONE; SCATTERING; ALGORITHM; GOMETRAN AB The radiative transfer forward model simulation of intensities and associated parameter derivatives (weighting functions) is a vital part of the retrieval of earth atmospheric constituent information from measurements of backscattered light. The discrete ordinate method is the most commonly used approach for the determination of solutions to the radiative transfer equation. In this paper, we carry out an internal perturbation analysis of the complete discrete ordinate solution in a plane parallel multi-layered multiple-scattering atmosphere. Perturbations in layer atmospheric quantities will translate into small changes in the single-scatter albedos and optical depth values. In addition, we consider perturbations in layer thermal emission source terms and in the surface albedo. It is shown that the solution of the boundary value problem for the perturbed intensity field leads in a natural way to the weighting function associated with the parameter causing the perturbation. We have developed a numerical model LIDORT (linearized discrete ordinate radiative transfer) for the simultaneous generation of backscatter intensities and weighting function output at arbitrary elevation angles, for a user-defined set of atmospheric variations. Results for a 5-layer test atmosphere with two scatterers and thermal emission terms are shown. Intensities are validated against benchmark discrete ordinate results, while weighting functions are checked for consistency against finite difference results based on external perturbations. A second example is presented for a 60-layer terrestrial atmosphere with molecular and aerosol scattering and ozone trace gas absorption in the UV spectral range; weighting functions are shown to correspond closely with results derived from another radiative transfer model. Published by Elsevier Science Ltd. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Spurr, RJD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Chance, Kelly/0000-0002-7339-7577 NR 36 TC 121 Z9 124 U1 1 U2 14 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 MAR 15 PY 2001 VL 68 IS 6 BP 689 EP 735 DI 10.1016/S0022-4073(00)00055-8 PG 47 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 400YL UT WOS:000166900200007 ER PT J AU Thaddeus, P McCarthy, MC AF Thaddeus, P McCarthy, MC TI Carbon chains and rings in the laboratory and in space SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE microwave spectroscopy; laser spectroscopy; interstellar molecules ID COUPLED-CLUSTER CALCULATIONS; LINEAR SILICON CARBIDES; AB-INITIO THEORY; ISOTOPIC-SUBSTITUTION; ROTATIONAL SPECTRA; C5H2 ISOMERS; MOLECULES; RADICALS; SIC3; ASTROCHEMISTRY AB Seventy-seven reactive organic molecules of astrophysical interest have been identified in a supersonic molecular beam, 73 in the radio band by Fourier-transform microwave spectroscopy, four in the optical by laser cavity ringdown spectroscopy. Most are linear carbon chains, but six consist of carbon chains attached to the compact, highly polar C-3 ring, and two are rhomboidal cyclic configurations of SiC3. The laboratory astrophysics of the radio molecules is complete for the time being, in the sense that essentially all the rotational transitions of current interest to radio astronomy (including hyperfine structure when present) can now be calculated to a small fraction of 1 km s(-1) in equivalent radial velocity; six of the radio molecules have already been detected in space on the basis of the present data. The FTM spectrometer employed in this work is far from fundamental limits of sensitivity, so many more molecules can probably be found by refinements of present techniques. The density of reactive molecules in our supersonic beam is generally high by the standards of laser spectroscopy, and many of the radio molecules probably have detectable optical transitions which we are attempting to find, largely motivated by the long-standing problem of the diffuse interstellar bands. Our most interesting result to date is the detection of a fairly strong molecular band at 443 nm in a benzene discharge, in exact coincidence with the strongest and best known interstellar band. Isotopic shifts measured with partially and totally deuterated benzene suggest that the carrier of the laboratory band is a hydrocarbon molecule with the elemental formula CnH5, with n most likely in the range 3-6. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM pthaddeus@cfa.harvard.edu OI McCarthy, Michael/0000-0001-9142-0008 NR 48 TC 86 Z9 88 U1 0 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD MAR 15 PY 2001 VL 57 IS 4 SI SI BP 757 EP 774 DI 10.1016/S1386-1425(00)00442-X PG 18 WC Spectroscopy SC Spectroscopy GA 418RY UT WOS:000167906200012 PM 11345252 ER PT J AU Lassiter, JC Luhr, JF AF Lassiter, JC Luhr, JF TI Osmium abundance and isotope variations in mafic Mexican volcanic rocks: Evidence for crustal contamination and constraints on the geochemical behavior of osmium during partial melting and fractional crystallization SO GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS LA English DT Article DE Os isotopes; sulfides; bulk partition coefficient; crustal contamination; oxygen fugacity; composition of the mantle; isotopic composition/chemistry; trace elements; igneous petrology ID RE-OS ISOTOPE; IONIZATION MASS-SPECTROMETRY; SAN-LUIS-POTOSI; SUBDUCTION ZONES; WESTERN MEXICO; EXPERIMENTAL GLASSES; LITHOSPHERIC MANTLE; SULFUR SPECIATION; OXIDATION-STATE; SILICATE MELT AB Primitive lavas and scoriae from the western Mexican Volcanic Belt (MVB) and the Mexican Basin and Range Province (MBRP) display a large range in Os concentrations and Os isotopes, with [Os] ranging from similar to 10 to 320 ppt and Os-187/Os-188 ranging from similar to0.128 to 0.207. Os concentrations and Os isotopes are correlated with abundances of MgO and Ni and with other indices of fractional crystallization, indicating that Os behaved as a compatible element during fractional crystallization. The high oxygen fugacity of subduction-related calc-alkaline and lamprophyric magmas from the western MVB precludes significant sulfide fractionation. Therefore Os must be compatible in at least one phase other than sulfide (e.g., olivine and/or Cr-spinel). The similarity of Os abundance trends in arc and nonarc suites suggests that Os concentrations are controlled primarily by equilibrium partitioning between melt with residual sulfide and silicate or oxide phases, and that D-Os (sulfide/melt) is less than similar to 2x10(5). Three chemically distinct Mexican volcanic suites, calc-alkaline basalts and lamprophyres from the western MVB and intraplate-type alkalic basalts from the MBRP, all display similar ranges in Os isotopes. Assimilation/fractional crystallization modeling suggests that the observed isotopic variations can be generated by minor (<12%) assimilation of Triassic age mafic lower crust. The least radiogenic samples still possess Os isotopes that are elevated relative to normal mantle peridotite. This difference may reflect variable input of radiogenic slab-derived fluids or melts into the source region of the Mexican magmas, with the slab signature strongest in the lamprophyres and calc-alkaline basalts and weakest in the intraplate-type alkalic basalts. Correlations between Os isotopes and Os concentrations in other arc suites and mid-ocean ridge basalts are unlikely to reflect mixing of distinct mantle components but instead reflect pervasive crustal (or seawater) contamination of magmas with low Os abundances. C1 Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. RP Lassiter, JC (reprint author), Max Planck Inst Chem, Postfach 3060, D-55020 Mainz, Germany. RI Lassiter, John/P-1892-2015 OI Lassiter, John/0000-0001-5249-168X NR 75 TC 16 Z9 16 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 1525-2027 J9 GEOCHEM GEOPHY GEOSY JI Geochem. Geophys. Geosyst. PD MAR 14 PY 2001 VL 2 AR 2000GC000116 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 458LG UT WOS:000170195400001 ER PT J AU Springel, V White, M Hernquist, L AF Springel, V White, M Hernquist, L TI Hydrodynamic simulations of the Sunyaev-Zeldovich effect(s) SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : theory; galaxies : clusters : general; large-scale structure of universe; methods : numerical ID MICROWAVE BACKGROUND ANISOTROPIES; SCALE ANISOTROPY; POWER SPECTRUM; CLUSTERS; GALAXIES; UNIVERSE; GHZ; SUPERCLUSTERS; FLUCTUATIONS; RADIATION AB We have performed a sequence of high-resolution hydrodynamic simulations of structure formation in a Lambda CDM model to study the thermal and kinetic Sunyaev-Zeldovich (SZ) effects. Including only adiabatic gas physics, we demonstrate that our simulations for the thermal effect are converged down to subarcminute scales. In this model, the angular power spectrum of cosmic microwave background (CMB) anisotropies induced by the thermal effect peaks at iota similar or equal to 10(4), and reaches an amplitude just below current observational upper limits. Fluctuations due to the kinetic effect are a factor of similar or equal to 30 lower in power and peak at slightly smaller angular scales. We identify individual SZ sources and compute their counts as a function of source strength and angular size. We present a preliminary investigation of the consequences of an early epoch of energy injection, which tends to suppress power on small angular scales, while giving rise to additional power on large scales from the reheated intergalactic matter (IGM) at high redshift. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. San Diego Supercomp Ctr, La Jolla, CA 92093 USA. RP Springel, V (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI White, Martin/I-3880-2015; OI White, Martin/0000-0001-9912-5070; Springel, Volker/0000-0001-5976-4599 NR 39 TC 156 Z9 156 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 MAR 10 PY 2001 VL 549 IS 2 BP 681 EP 687 DI 10.1086/319473 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413GX UT WOS:000167605200002 ER PT J AU Macri, LM Calzetti, D Freedman, WL Gibson, BK Graham, JA Huchra, JP Hughes, SMG Madore, BF Mould, JR Persson, SE Stetson, PB AF Macri, LM Calzetti, D Freedman, WL Gibson, BK Graham, JA Huchra, JP Hughes, SMG Madore, BF Mould, JR Persson, SE Stetson, PB TI NICMOS observations of extragalactic Cepheids. I. Photometry database and a test of the standard extinction law SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; distance scale; galaxies : stellar content ID HUBBLE-SPACE-TELESCOPE; SCALE KEY PROJECT; DISTANCE SCALE; PEAK BRIGHTNESS; DISCOVERY; CALIBRATION AB We present the results of near-infrared observations of extragalactic Cepheids made with the Near-Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST). The variables are located in the galaxies IC 1613, IC 4182, M31, M81, M101, NGC 925, NGC 1365, NGC 2090, NGC 3198, NGC 3621, NGC 4496A, and NGC 4536. All fields were observed in the F160W bandpass; additional images were obtained in the F110W and F205W filters. Photometry was performed using the DAOPHOT II/ALLSTAR package. Self-consistent distance moduli and color excesses were obtained by fitting period-luminosity relations in the H, I, and V bands. Our results support the assumption of a standard reddening law adopted by the HST Key Project on the Extragalactic Distance Scale. A companion paper will determine true distance moduli and explore the effects of metallicity on the Cepheid distance scale. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Swinburne Univ Technol, Ctr Astrophys & Supercomp, Hawthorn, Vic 3122, Australia. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Royal Greenwich Observ, Cambridge CB3 0EZ, England. CALTECH, NASA, IPAC, Pasadena, CA 91125 USA. Australian Natl Univ, Inst Adv Studies, Res Sch Astron & Astrophys, Mt Stromlo Observ, Weston Creek, ACT 2611, Australia. Natl Res Council Canada, Herzberg Inst Astrophys, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. RP Macri, LM (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 20, Cambridge, MA 02138 USA. RI Gibson, Brad/M-3592-2015; OI Gibson, Brad/0000-0003-4446-3130; Macri, Lucas/0000-0002-1775-4859 NR 28 TC 59 Z9 59 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2001 VL 549 IS 2 BP 721 EP 744 DI 10.1086/319465 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413GX UT WOS:000167605200007 ER PT J AU Soker, M White, RE David, LP McNamara, BR AF Soker, M White, RE David, LP McNamara, BR TI A moderate cluster cooling flow model SO ASTROPHYSICAL JOURNAL LA English DT Article DE cooling flows; galaxies : clusters : general; intergalactic medium ID EMISSION-LINE NEBULAE; RAY LUMINOUS CLUSTERS; H-I ABSORPTION; GALAXY HYDRA-A; MAGNETIC-FIELDS; RADIO JETS; FARADAY-ROTATION; INTRACLUSTER MEDIUM; STAR-FORMATION; MOLECULAR GAS AB We propose that the outer portions of cooling flows in clusters of galaxies are frequently disrupted by radio jets and that their effective ages are much shorter than the cluster ages. The inner regions, where the gas density is higher, are more difficult to disrupt and may continue to harbor cooling flows even after disruption events. The main assumption of the proposed scenario is that, on a timescale of similar to2-4 x 10(9) yr, the cD galaxies in cooling flow clusters undergo powerful bursts of active galactic nucleus (AGN) activity that produce strong radio jets. The radio jets excite shocks in the inner regions (r less than or similar to 100 kpc) of cooling flow clusters. A radio burst may result from the accretion of cooling material by the central black hole or from a collision with a subcluster. We assume that the jets remain strong, with kinetic powers of similar to 10(47) ergs s(-1) for similar to 10(7) yr. The jets excite shock waves moving at several times 10(3) km s(-1) and heat the cooling flow region, hence terminating it in the outer regions. The proposed scenario predicts that the total accreted mass due to the cooling flow is an order of magnitude lower than the mass accreted according to the "standard" cooling flow model (which assumes an undisturbed cooling flow for a time equal to the age of the cluster). The scenario, therefore, brings into agreement the observations that (1) a large fraction of clusters harbor cooling flows, (2) strong optical and radio activity are present only in the very inner regions of cooling flows, and (3) there is a lack of a satisfactory reservoir of the expected (in the standard cooling flow model) large mass that has been cooling over the life of the cluster. C1 Univ Haifa Oranim, Dept Phys, IL-36006 Tivon, Israel. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Soker, M (reprint author), Univ Haifa Oranim, Dept Phys, IL-36006 Tivon, Israel. NR 66 TC 9 Z9 9 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2001 VL 549 IS 2 BP 832 EP 839 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413GX UT WOS:000167605200014 ER PT J AU Chou, Y Grindlay, JE Bloser, PF AF Chou, Y Grindlay, JE Bloser, PF TI Timing analysis of the light curve of the dipping-bursting X-ray binary X1916-053 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (X1916-053); X-rays : stars ID AM-CANUM-VENATICORUM; ACCRETION DISKS; 4U 1915-05; SUPERHUMPS; SIMULATIONS; 4U-1915-05; ABSORPTION; DISCOVERY; GINGA AB We present the timing analysis results for our observations of the X-ray dip source X1916-053 conducted with RXTE between February and October of 1996. Our goal was to finally measure the binary period-as either the X-ray dip period or the similar to1% longer optical modulation period-thereby establishing whether the binary has a precessing disk (SU UMa model) or a third star (triple model). Combined with historical data (1979-1996), the X-ray dip period is measured to be 3000.6508 +/- 0.0009 s with a 2 sigma upper limit \(P)over dot\ less than or equal to 2.06 x 10(-11). From our quasi-simultaneous optical observations (1996 May 14-23) and historical data (1987-1996), we measure the optical modulation period to be 3027.5510 +/- 0.0052 s with a 2 sigma upper limit \(P)over dot\ less than or equal to 2.28 x 10(-10). The two periods are therefore each stable (over all recorded data) and require a 3.9087 +/- 0.0008 day beat period. This beat period, and several of its harmonics, is also observed as variations in the dip shape. Phase modulation of X-ray dips, observed in a 10 consecutive day observation, is highly correlated with the similar to3.9 day dip shape modulation. The 1987-1996 optical observations show that the optical phase fluctuations are a factor of 3 larger than those in the X-ray. We discuss SU UMa versus triple models to describe the X1916-053 light-curve behavior and conclude that the X-ray dip period, with smaller phase jitter, is probably the binary period, so that the required precession is most likely similar to that observed in SU UMa and X-ray nova systems. However, the "precession" period stability, and especially the fact that the times of X-ray bursts may partially cluster to occur just after X-ray dips, continues to suggest that this system may be a hierarchical triple. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Chou, Y (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Chou, Yi/C-4922-2008 OI Chou, Yi/0000-0002-8584-2092 NR 33 TC 30 Z9 30 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2001 VL 549 IS 2 BP 1135 EP 1144 DI 10.1086/319443 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413GX UT WOS:000167605200038 ER PT J AU Habbal, SR Woo, R AF Habbal, SR Woo, R TI Connecting the sun and the solar wind: Comparison of the latitudinal profiles of coronal and Ulysses measurements of the fast wind SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : corona ID MAGNETIC-FIELD; INTERPLANETARY SPACE; HOLE; POLE AB A quantitative comparison of the latitudinal profile of polarized brightness (pB) measurements nearest the Sun at 1.15 R. by the Mauna Loa Solar Observatory K-Coronameter and Ulysses interplanetary measurements of the fast solar wind during its first south polar pass, at the declining phase of the solar cycle, is made for the first time to identify the sources of the fast solar wind in the context of coronal density structure. Both profiles are found to have the same shape. At the Sun, the minimum coincides with the radial extension of the coronal hole boundaries. The slight rise and plateau following this minimum toward lower latitudes are identified with the coronal extension of the quiet Sun. The corresponding profile of the in situ measured velocity has a maximum within the angular extent of the polar coronal hole and decreases gradually beyond its boundaries. The latitudinal profile of the proton flux mimics the density profile, implying that the mass-loss rate is lowest within the angular extent of the polar coronal hole. The association of the fast wind with a density profile that reflects the polar coronal hole and the surrounding quiet Sun suggests that the fast wind observed by Ulysses originates from both regions. That these conclusions differ from earlier published analyses of the same Ulysses measurements is a consequence of the quantitative and systematic comparison made between Ulysses and coronal measurements at 1.15 R.. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Habbal, SR (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 29 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 MAR 10 PY 2001 VL 549 IS 2 BP L253 EP L256 DI 10.1086/319172 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 417JB UT WOS:000167830900023 ER PT J AU Marshall, HL Harris, DE Grimes, JP Drake, JJ Fruscione, A Juda, M Kraft, RP Mathur, S Murray, SS Ogle, PM Pease, DO Schwartz, DA Siemiginowska, AL Vrtilek, SD Wargelin, BJ AF Marshall, HL Harris, DE Grimes, JP Drake, JJ Fruscione, A Juda, M Kraft, RP Mathur, S Murray, SS Ogle, PM Pease, DO Schwartz, DA Siemiginowska, AL Vrtilek, SD Wargelin, BJ TI Structure of the X-ray emission from the jet of 3C 273 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : jets; quasars : individual (3C 273); X-rays : galaxies ID HUBBLE-SPACE-TELESCOPE; 3C-273; PKS-0637-752 AB We present images from five observations of the quasar 3C 273 with the Chandra X-Ray Observatory. The jet has at least four distinct features that are not resolved in previous observations. The first knot in the jet (A1) is very bright in X-rays. Its X-ray spectrum is well fitted with a power law with alpha = 0.60 +/- 0.05 (where S, proportional to nu (-alpha)). Combining this measurement with lower frequency data shows that a pure synchrotron model can fit the spectrum of this knot from 1.647 GHz to 5 keV (over nine decades in energy) with alpha = 0.76 +/- 0.02, similar to the X-ray spectral slope. Thus, we place a lower limit on the total power radiated by this knot of 1.5 x 10(43) ergs s(-1); substantially more power may be emitted in the hard X-ray and gamma -ray bands. Knot A2 is also detected and is somewhat blended with knot B1. Synchrotron emission may also explain the X-ray emission, but a spectral bend is required near the optical band. For knots A1 and B1, the X-ray flux dominates the emitted energy. For the remaining optical knots (C through H), localized X-ray enhancements that might correspond to the optical features are not clearly resolved. The position angle of the jet ridge line follows the optical shape with distinct, aperiodic excursions of +/- 1 degrees from a median value of -138.degrees0. Finally, we find X-ray emission from the "inner jet" between 5" and 10" from the core. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Marshall, HL (reprint author), MIT, Ctr Space Res, 70 Vassar St, Cambridge, MA 02139 USA. OI Juda, Michael/0000-0002-4375-9688 NR 9 TC 105 Z9 106 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 MAR 10 PY 2001 VL 549 IS 2 BP L167 EP L171 DI 10.1086/319161 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 417JB UT WOS:000167830900004 ER PT J AU Miralles, MP Cranmer, SR Panasyuk, AV Romoli, M Kohl, JL AF Miralles, MP Cranmer, SR Panasyuk, AV Romoli, M Kohl, JL TI Comparison of empirical models for polar and equatorial coronal holes SO ASTROPHYSICAL JOURNAL LA English DT Article DE line : profiles; solar wind; Sun : corona; Sun : UV radiation; techniques : spectroscopic ID SOLAR-WIND; STRAY-LIGHT; SPECTROMETER; UVCS/SOHO; OUTFLOW AB We present a self-consistent empirical model for several plasma parameters of a large equatorial coronal hole observed on 1999 November 12 near solar maximum. The model was derived from observations with the Ultraviolet Coronagraph Spectrometer on the Solar and Heliospheric Observatory. In this Letter, we compare the observations of O VI lambda lambda 1032, 1037 emission lines with previous observations of a polar coronal hole observed near solar minimum. At the time of the 1999 observations, there was no evidence of large polar coronal holes. The resulting empirical model for the equatorial coronal hole describes the outflow velocities and most probable speeds for O5+, and we compared the derived ion properties with the empirical model for a solar minimum polar coronal hole. The comparison of the empirical models shows that the 1999 equatorial hole has lower O5+ outflow speeds and perpendicular temperatures than its polar counterpart from 1996 to 1997 at heights between 2 and 3 R.. However, in situ asymptotic speeds of the wind streams coming from the 1996-1997 polar hole and from the 1999 equatorial hole are only similar to 15% different. Thus, the bulk of the solar wind acceleration must occur above 3 R. for the equatorial coronal hole. The equatorial hole also has a higher density than the polar hole at similar heights. It is not yet known whether the higher densities are responsible for the seeming inhibition of the fast ion outflow speeds and extremely large perpendicular temperatures that occur in polar coronal holes at solar minimum. We discuss the constraints and implications on various theoretical models of coronal heating and acceleration. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. RP Miralles, MP (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 50, Cambridge, MA 02138 USA. RI Romoli, Marco/H-6859-2012 NR 21 TC 36 Z9 36 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 MAR 10 PY 2001 VL 549 IS 2 BP L257 EP L260 DI 10.1086/319166 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 417JB UT WOS:000167830900024 ER PT J AU Arnoldi, MJ AF Arnoldi, MJ TI Photo essay: Somono Puppet Masquerades in Kirango, Mali (Performances organized on fishing boats on the banks of the Niger River) SO AFRICAN ARTS LA English DT Article C1 Smithsonian Inst, Washington, DC 20560 USA. RP Arnoldi, MJ (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CALIF PI LOS ANGELES PA AFRICAN STUDIES CNTR, LOS ANGELES, CA 90024 USA SN 0001-9933 J9 AFR ARTS JI Afr. Arts PD SPR PY 2001 VL 34 IS 1 BP 72 EP 77 PG 6 WC Art SC Art GA 446AY UT WOS:000169491800013 ER PT J AU Mullen Kreamer, C AF Mullen Kreamer, C TI Body art: Marks of identity SO AFRICAN ARTS LA English DT Art Exhibit Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Mullen Kreamer, C (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU UNIV CALIF PI LOS ANGELES PA AFRICAN STUDIES CNTR, LOS ANGELES, CA 90024 USA SN 0001-9933 J9 AFR ARTS JI Afr. Arts PD SPR PY 2001 VL 34 IS 1 BP 83 EP 85 PG 3 WC Art SC Art GA 446AY UT WOS:000169491800015 ER PT J AU Mullen Kreamer, C AF Mullen Kreamer, C TI Hair in African art and culture SO AFRICAN ARTS LA English DT Art Exhibit Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Mullen Kreamer, C (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU UNIV CALIF PI LOS ANGELES PA AFRICAN STUDIES CNTR, LOS ANGELES, CA 90024 USA SN 0001-9933 J9 AFR ARTS JI Afr. Arts PD SPR PY 2001 VL 34 IS 1 BP 85 EP 86 PG 2 WC Art SC Art GA 446AY UT WOS:000169491800016 ER PT J AU Whitney, CA AF Whitney, CA TI Stellar engines SO AMERICAN SCIENTIST LA English DT Letter C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Whitney, CA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 USA SN 0003-0996 J9 AM SCI JI Am. Scientist PD MAR-APR PY 2001 VL 89 IS 2 BP 107 EP 108 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 400YH UT WOS:000166899900005 ER PT J AU Grand, TI Barboza, FS AF Grand, TI Barboza, FS TI Anatomy and development of the koala, Phascolarctos cinereus: an evolutionary perspective on the superfamily Vombatoidea SO ANATOMY AND EMBRYOLOGY LA English DT Article DE locomotor anatomy; life history; lactation energetics; brain and muscle growth; wombats ID HAIRY-NOSED WOMBAT; FIELD METABOLIC-RATE; LASIORHINUS-LATIFRONS; HINDGUT FERMENTATION; TISSUE COMPOSITION; FOOD-CONSUMPTION; MOTOR FUNCTION; BODY-WEIGHT; WATER FLUX; MARSUPIALIA AB Fifteen koalas (Phascolarctos cinereus) - pouched young from 4 to 6.5 months and 10 adults from 5 to 16.5 years - were analyzed for functional parameters (body composition, limb segment and muscle mass, post-cranial skeletal characters) and developmental expressions (growth of body, brain, musculature). These data were compared with a convergent eutherian, the three-toed sloth, Bradypus infuscatus, and with the koala's distant (Macropodid; wallabies) and proximate (Vombatid; wombats) marsupial relatives. Musculoskeletal structures correlated with sitting and climbing, the growth of the young and the physiological demands of adulthood correlated with the low-quality diet of Eucalyptus foliage. The gestalt of the ancestral Vombatoids (pronograde quadrupeds, generalist browsers and social conservatives with low basal metabolism and attenuated development) provided the baseline essential for their locomotor and nutritional divergence into arboreal browsers, the koalas, and fossorial grazers, the wombats. C1 Smithsonian Inst, Natl Zool Pk, Dept Pathol, Washington, DC 20008 USA. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Grand, TI (reprint author), Smithsonian Inst, Natl Zool Pk, Dept Pathol, Washington, DC 20008 USA. NR 95 TC 10 Z9 11 U1 7 U2 41 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-2061 J9 ANAT EMBRYOL JI Anat. Embryol. PD MAR PY 2001 VL 203 IS 3 BP 211 EP 223 DI 10.1007/s004290000153 PG 13 WC Anatomy & Morphology; Developmental Biology SC Anatomy & Morphology; Developmental Biology GA 411WV UT WOS:000167523200006 PM 11303907 ER PT J AU Vrsansky, P Storozhenko, SY Labandeira, CC Ihringova, P AF Vrsansky, P Storozhenko, SY Labandeira, CC Ihringova, P TI Galloisiana olgae sp nov (Grylloblattodea : Grylloblattidae) and the paleobiology of a relict order of insects SO ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA LA English DT Article DE Galloisiana olgae; Grylloblattodea; rock crawlers; new species; paleobiology; Ussuri River Basin ID CRYPTOCERCUS-CLEVELANDI; BIOGEOGRAPHY; DICTYOPTERA AB An extant species of the relict insect order Grylloblattodea is described from the Ussuri River Basin of southeastern Russia. This species, Galloisiana olgae, is a member of the family Grylloblattidae that probably originated as a lineage during the mid-Cenozoic and experienced subsequent range constriction associated with Pleistocene glaciation. The Grylloblattodea have a richer fossil history in warm-temperate habitats during the Late Paleozoic than the four confamilial genera of today would suggest. These modern taxa represent a specialized Cenozoic lineage that adapted to cool-temperate habitats in northwestern North America and northeastern Asia, and parallel other similar distributions of seed plants and insects. C1 Comenius Univ, Dept Zool, Bratislava 84215, Slovakia. Inst Paleontol, Moscow 117647, Russia. Inst Biol & Pedol, Vladivostok 690022, Russia. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. Univ Maryland, Dept Entomol, College Pk, MD 20742 USA. AMBA Projects, Bratislava 81102, Slovakia. RP Vrsansky, P (reprint author), Comenius Univ, Dept Zool, Mlynska Dolina B1, Bratislava 84215, Slovakia. NR 45 TC 18 Z9 19 U1 0 U2 3 PU ENTOMOL SOC AMER PI LANHAM PA 9301 ANNAPOLIS RD, LANHAM, MD 20706 USA SN 0013-8746 J9 ANN ENTOMOL SOC AM JI Ann. Entomol. Soc. Am. PD MAR PY 2001 VL 94 IS 2 BP 179 EP 184 DI 10.1603/0013-8746(2001)094[0179:GOSNGG]2.0.CO;2 PG 6 WC Entomology SC Entomology GA 416RJ UT WOS:000167793700004 ER PT J AU Willmott, KR Constantino, LM Hall, JPW AF Willmott, KR Constantino, LM Hall, JPW TI A review of Colobura (Lepidoptera : Nymphalidae) with comments on larval and adult ecology and description of a sibling species SO ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA LA English DT Review DE Colobura; early stages; hostplants; Neotropical; taxonomy AB The taxonomy of the genus Colobura Billberg, 1820, one of the most common members of the Neotropical lowland forest butterfly fauna, is critically reviewed in light of available information on the morphology of both the immature stages and adults. Although regarded by almost all authors to date as monotypic, Colobura contains two species, one of which is described here as Colobura annulata sp, n. The immature stages of both the new species and Colobura dirce (Linnaeus, 1758) are described, compared, and figured. Both larval and adult phenotypes of the two species may be readily separated. and a key to identification is provided. A review of published and unpublished information on the immature stages, hostplants, and adult behavior of both species reveals a possible case of ecological niche partitioning; larvae of C. dirce are solitary or occur in small groups on predominantly young trees or saplings, whereas those of C. annulata are highly gregarious on mature canopy trees. There is some evidence to suggest that adult night height may, in part be correlated with the height of preferred hostplants. C1 Univ Florida, Dept Zool, Gainesville, FL 32611 USA. Fdn Herencia Verde, Cali 32802, Colombia. Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, Washington, DC 20560 USA. RP Willmott, KR (reprint author), Univ Florida, Dept Zool, Gainesville, FL 32611 USA. NR 59 TC 5 Z9 7 U1 0 U2 3 PU ENTOMOL SOC AMER PI LANHAM PA 9301 ANNAPOLIS RD, LANHAM, MD 20706 USA SN 0013-8746 J9 ANN ENTOMOL SOC AM JI Ann. Entomol. Soc. Am. PD MAR PY 2001 VL 94 IS 2 BP 185 EP 196 DI 10.1603/0013-8746(2001)094[0185:AROCLN]2.0.CO;2 PG 12 WC Entomology SC Entomology GA 416RJ UT WOS:000167793700005 ER PT J AU Barmby, P Huchra, JP Brodie, JP AF Barmby, P Huchra, JP Brodie, JP TI The M31 globular cluster luminosity function SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (M31); galaxies : star clusters; globular clusters : general ID INFRARED STANDARD STARS; HUBBLE CONSTANT; SELF-ENRICHMENT; GALACTIC HALO; VIRGO CLUSTER; MASS FUNCTION; INNER REGION; SYSTEM; GALAXIES; EVOLUTION AB We combine our compilation of photometry of M31 globular clusters and probable cluster candidates with new near-infrared photometry for 30 objects. Using these data we determine the globular cluster luminosity function (GCLF) in multiple filters for the M31 halo clusters. We find a GCLF peak and dispersion V-0(0) = 16.84 +/- 0.11, sigma (iota) =0.93 +/- 0.13 (Gaussian sigma = 1.20 +/- 0.14), consistent with previous results. The halo GCLF peak colors (e.g., B-0(0) - V-0(0)) are consistent with the average cluster colors. We also measure V-band GCLF parameters for several other subsamples of the M31 globular cluster population. The inner third of the clusters have a GCLF peak significantly brighter than that of the outer clusters (DeltaV(0) approximate to 0.5 mag). Dividing the sample by both galactocentric distance and metallicity, we find that the GCLF also varies with metallicity, as the metal-poor clusters are on average 0.36 mag fainter than the metal-rich clusters. Our modeling of the catalog selection effects suggests that they are not the cause of the measured GCLF differences, but a more complete, less contaminated M31 cluster catalog is required for confirmation. Our results imply that dynamical destruction is not the only factor causing variation in the M31 GCLF: metallicity, age, and cluster initial mass function may also be important. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. RP Barmby, P (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Barmby, Pauline/I-7194-2016 OI Barmby, Pauline/0000-0003-2767-0090 NR 74 TC 66 Z9 66 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 MAR PY 2001 VL 121 IS 3 BP 1482 EP 1496 DI 10.1086/319389 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 412YL UT WOS:000167582800021 ER PT J AU Blair, WP Fesen, RA Schlegel, EM AF Blair, WP Fesen, RA Schlegel, EM TI Hubble Space Telescope images of the ultraluminous supernova remnant complex in NGC 6946 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 6946); supernova remnants ID SPECTRAL ENERGY-DISTRIBUTIONS; MAGELLANIC CLOUD; SPIRAL GALAXIES; CYGNUS-LOOP; X-RAY; NGC-6946; DISTANCE; N132D; M33 AB We present Hubble Space Telescope (HST) narrow-passband H alpha and [S II] images and broadband continuum images of the region around an extremely luminous optical and X-ray supernova remnant complex in the spiral galaxy NGC 6946. These images, obtained with the PC1 CCD of the Wide Field Planetary Camera 2, show a circular, limb-brightened shell of diameter 0.35 " [9 d/(5.1 Mpc) pc] superposed on the edge of a larger, lower surface brightness elliptical shell (1.4 " x 0.8 ", or similar or equal to 34 pc x 20 pc). The HST images allow us to see that the [S II]:H alpha ratio remains high across both shells, indicating that both are collisionally heated. A brightening of the H alpha and [S II] line emission arises on the eastern side of the smaller shell, where it is apparently interacting with the western edge of the larger shell. Our HST V image includes the nebula's strong [O III] lambda 5007 emission in the blue wing of the filter, providing a glimpse at the [O III] nebular morphology. The smaller shell looks similar, but the extended structure looks sharper than in H alpha and [S II] images, reminiscent of a cavity wall. The HST and ground-based continuum images show the brightest members of the underlying and adjacent stellar population, indicating the presence of massive OB stars in and near the region. A new optical ground-based spectrum confirms that the [N II]:H alpha ratio is enhanced in the region, consistent with mass loss from massive stars. These data show an average ([S II] lambda lambda 6716, 6731): Ha ratio across both shells of similar to1 and a mean electron density of similar to 400 cm(-3), indicating preshock densities of order 10 cm(-3). We interpret this nebular morphology and supporting information as an indication of multiple supernova explosions in relatively close temporal and spatial proximity. We discuss possible scenarios for this complex region and the reasons for its extreme luminosity. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Dartmouth Coll, Dept Phys & Astron, Wilder Lab 6127, Hanover, NH 03755 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Blair, WP (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 26 TC 24 Z9 24 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 2001 VL 121 IS 3 BP 1497 EP 1506 DI 10.1086/319426 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 412YL UT WOS:000167582800022 ER PT J AU Haisch, KE Lada, EA Pina, RK Telesco, CM Lada, CJ AF Haisch, KE Lada, EA Pina, RK Telesco, CM Lada, CJ TI A mid-infrared study of the young stellar population in the NGC 2024 cluster SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; open clusters and associations : individual (NGC 2024); stars : formation ID AURIGA MOLECULAR CLOUD; T-TAURI STARS; CIRCUMSTELLAR DISKS; LUMINOSITY FUNCTIONS; INFRARED IMAGES; OPHIUCHI CLOUD; EVOLUTION; OBJECTS; PROTOSTARS; MASSES AB We present the results of the first broadband N (10.8 mum) survey of the NGC 2024 cluster. The mid-infrared data were combined with our previously published JHKL photometry to construct spectral energy distributions for all detected sources. The main scientific goals were to investigate the nature of the young stellar objects (YSOs) in the cluster and to examine the efficiency of detecting circumstellar disk sources from near-infrared JHKL color-color diagrams. Out of 59 sources surveyed having K-band (2.2 mum) magnitudes m(K) less than or equal to 10.5, we detected 35 (similar to 59%) at 10 mum. Combining these detections and upper limits for the nondetections with existing JHKL data, we identify one Class I, six flat-spectrum, 28 Class II, and five Class III sources. We find a circumstellar disk fraction for NGC 2024 of similar to 85% +/- 15%, which confirms earlier published suggestions that the majority, if not all, of the stars in the NGC 2024 cluster formed with disks, and these disks still exist at the present time. In addition, all but one of the disk sources identified in our survey lie in the infrared-excess region of the JHKL color-color diagram for the NGC 2024 cluster. This demonstrates that JHKL color-color diagrams are extremely efficient in identifying YSOs with circumstellar disks. Of the 14 sources in our survey with K - L colors suggestive of protostellar objects, similar to 29% are protostellar in nature, while similar to7% are true Class I sources. This may be due to extinction producing very red K - L colors in Class II YSOs, thus making them appear similar in color to protostars. This suggests that caution must be applied when estimating the sizes and lifetimes of protostellar populations within star-forming regions based on K - L colors alone. A comparison of the ratio of the number of Class I and flat-spectrum sources to the number of Class II and III sources in NGC 2024, rho Oph, and Taurus-Auriga indicates that NGC 2024 and rho Oph have similar ages, while Taurus-Auriga is an older region of star formation, consistent with published T Tauri star ages in each region. Finally, we calculate the luminosities of the Class II sources in NGC 2024, rho Oph, and Taurus and discuss the results. C1 Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Haisch, KE (reprint author), Univ Florida, Dept Astron, 211 SSRB, Gainesville, FL 32611 USA. NR 29 TC 44 Z9 44 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 2001 VL 121 IS 3 BP 1512 EP 1521 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 412YL UT WOS:000167582800024 ER PT J AU Kaluzny, J Olech, A Stanek, KZ AF Kaluzny, J Olech, A Stanek, KZ TI Image-subtraction photometry of variable stars in the field of the globular cluster NGC 6934 SO ASTRONOMICAL JOURNAL LA English DT Article DE color-magnitude diagrams; globular clusters : individual (NGC 6934); methods : data analysis; stars : oscillations; stars : variables : other ID RR-LYRAE STARS; DETACHED ECLIPSING BINARIES; DIRECT DISTANCES; METALLICITY; PARAMETERS; PULSATION; CEPHEIDS; NGC-6362; SYSTEM; LIGHT AB We present CCD BV I photometry of 85 variable stars from the field of the globular cluster NGC 6934. The photometry was obtained with the image subtraction package ISIS. 35 variables are new identifications : 24 RRab stars, five RRc stars, two eclipsing binaries of W UMa-type, one SX Phe star, and three variables of other types. Both detected contact binaries are foreground stars. The SX Phe variable belongs most likely to the group of cluster blue stragglers. Large number of newly found RR Lyr variables in this cluster, as well as in other clusters recently observed by us, indicates that total RR Lyr population identified up to date in nearby galactic globular clusters is significantly (>30%) incomplete. Fourier decomposition of the light curves of RR Lyr variables was used to estimate the basic properties of these stars. From the analysis of RRc variables we obtain a mean mass of M = 0.63 M ., luminosity log L/L. = 1.72, effective temperature T-eff = 7300 and helium abundance Y = 0.27. The mean values of the absolute magnitude, metallicity (on Zinn's scale) and effective temperature for RRab variables are M-V = 0.81, [Fe/H] = -1.53 and T-eff = 6450, respectively. From the B-V color at minimum light of the RRab variables we obtained the color excess to NGC 6934 equal to E(B-V) = 0.09 +/- 0.01. Different calibrations of absolute magnitudes of RRab and RRc available in literature were used to estimate apparent distance modulus of the cluster : (m-M)(V) = 16.09 +/- 0.06. We note a likely error in the zero point of the HST-based V-band photometry of NGC 6934 recently presented by Piotto et al. Among analyzed sample of RR Lyr stars we have detected a short period and low amplitude variable which possibly belongs to the group of second overtone pulsators (RRe subtype variables). The BVI photometry of all variables is available electronically via anonymous ftp. The complete set of the CCD frames is available upon request. C1 Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Warsaw Univ Observ, PL-00478 Warsaw, Poland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kaluzny, J (reprint author), Copernicus Astron Ctr, Ul Bartycka 18, PL-00716 Warsaw, Poland. NR 45 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 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 2001 VL 121 IS 3 BP 1533 EP 1550 DI 10.1086/319411 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 412YL UT WOS:000167582800026 ER PT J AU Beltran, MT Estalella, R Anglada, G Rodriguez, LF Torrelles, JM AF Beltran, MT Estalella, R Anglada, G Rodriguez, LF Torrelles, JM TI Radio spectral indices of the powering sources of outflows SO ASTRONOMICAL JOURNAL LA English DT Article DE ISM : jets and outflows; radio continuum; stars : formation ID YOUNG STELLAR OBJECTS; STAR-FORMING REGIONS; FREE-FREE RADIATION; H-II REGIONS; IRAS SOURCES; CONTINUUM EMISSION; AMMONIA OBSERVATIONS; MOLECULAR OUTFLOWS; WATER MASERS; RHO-OPHIUCHI AB Eight regions containing molecular or HH outflows (Mon R2E, S287, L1654, L483, PV Cephei, L1203, L1251A, and CB 247) have been observed with the VLA at 6 cm, and a total of 55 sources have been detected above a 5 sigma level. By combining our observations at 6 cm with previous data obtained at 3.6 cm, we estimate the spectral indices of the sources in the fields. For 32 of the sources we discriminate the sign of the spectral index and thus, we obtain information about the nature of the emission. For seven outflows (Mon R2E, S287-B, L1654, L483, PV Cephei, L1203, and L1251A) we found at least a central source with an spectral index consistent with thermal free-free emission from thermal radio jets. Multiple sources, separated similar to 10 ", are found near the center of the Mon R2E, S287-B, L1654, and L1251A outflows. In the case of S287-B we found two sources that are valid candidates to drive the S287-B molecular outflow and could be related to the outflow excitation. Under the assumption that the observed emission arises from thermal radio jets, we discuss the mechanism responsible for the ionization and the constraints that introduces on their physical parameters, and we estimate that the flow of ionized material has to originate at a few AU from the exciting star. Most of the remaining, noncentral, sources are characterized by negative spectral indices (alpha < -0.1) and are probably nonthermal background objects unrelated to the studied star-forming regions. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Barcelona, Dept Astron & Meteorol, E-08028 Barcelona, Spain. CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain. Univ Nacl Autonoma Mexico, Inst Astron, Morelia 58089, Michoacan, Mexico. CSIC, IEEC, E-08034 Barcelona, Spain. CSIC, Inst Ciencias Espacio, E-08034 Barcelona, Spain. RP Beltran, MT (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM mbeltran@cfa.harvard.edu; robert.estalella@am.ub.es; guillem@iaa.es; luisfr@astrosmo.unam.mx; torrelles@ieec.fcr.es OI Beltran Sorolla, Maria Teresa/0000-0003-3315-5626; Torrelles, Jose Maria/0000-0002-6896-6085 NR 59 TC 41 Z9 41 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 2001 VL 121 IS 3 BP 1556 EP 1568 DI 10.1086/319394 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 412YL UT WOS:000167582800028 ER PT J AU Matheson, T Filippenko, AV Li, WD Leonard, DC Shields, JC AF Matheson, T Filippenko, AV Li, WD Leonard, DC Shields, JC TI Optical spectroscopy of type Ib/c supernovae SO ASTRONOMICAL JOURNAL LA English DT Review DE gamma rays; stars : mass loss; supernovae : general ID GAMMA-RAY BURSTS; HELIUM STAR MODELS; 25 APRIL 1998; SPECTRAL ENERGY-DISTRIBUTIONS; HE-I LINES; HYPERNOVA MODEL; RADIO-EMISSION; STANDARD STARS; LOW-RESOLUTION; IIB SUPERNOVA AB We present 84 spectra of Type Ib/c and Type IIb supernovae (SNe), describing the individual SNe in detail. The relative depths of the helium absorption lines in the spectra of the SNe Ib appear to provide a measurement of the temporal evolution of the SN, with He I lambda 5876 and He I lambda 7065 growing in strength relative to He I lambda 6678 over time. Light curves for three of the SNe Ib provide a sequence for correlating the helium line strengths. We find that some SNe Ic show evidence for weak helium absorption, but most do not. Aside from the presence or absence of the helium lines, there are other spectroscopic differences between SNe Ib and SNe Ic. On average, the O I lambda 7774 line is stronger in SNe Ic than in SNe Ib. In addition, the SNe Ic have distinctly broader emission lines at late times, indicating a consistently larger explosion energy and/or lower envelope mass for SNe Ic than for SNe Ib. While SNe Ib appear to be basically homogeneous, the SNe Ic are quite heterogeneous in their spectroscopic characteristics. Three SNe Ic that may have been associated with gamma-ray bursts are also discussed; two of these have clearly peculiar spectra, while the third seems fairly typical. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Ohio Univ, Dept Phys & Astron, Athens, OH 45701 USA. RP Matheson, T (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM matheson@astron.berkeley.edu; alex@astron.berkeley.edu; weidong@astron.berkeley.edu; leonard@astron.berkeley.edu; shields@phy.ohiou.edu NR 185 TC 120 Z9 120 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 2001 VL 121 IS 3 BP 1648 EP 1675 DI 10.1086/319390 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 412YL UT WOS:000167582800037 ER PT J AU Groot, PJ Rutten, RGM van Paradijs, J AF Groot, PJ Rutten, RGM van Paradijs, J TI SW Sextantis in an excited, low state SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, accretion disks; binaries : eclipsing; stars : individual : SW Sex; novae, cataclysmic variables ID UX-URSAE-MAJORIS; ACCRETION DISK; CATACLYSMIC VARIABLES; V1315 AQUILAE; ECLIPSE MAPS; PG 1012-029; V-PERSEI; MASS; SPECTROSCOPY; ABSORPTION AB We present low-resolution spectrophotometric optical observations of the eclipsing nova-like cataclysmic variable SW Sex, the prototype of the SW Sex stars. We observed the system when it was in an unusual low state. The spectrum is characterized by the presence of strong HeII and CIV emission lines as well as the normal single peaked Palmer emission lines. The radial temperature profile of the disk follows the expected T proportional to R-3/4 only in the outer parts and flattens off inside 0.5 times the white dwarf Roche lobe radius. The single peaked emission lines originate in a region above the plane of the disk, at the position of the hot spot. C1 CHEAF, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Isaac Newton Grp Telescopes, Sta Cruz De La Palma 38700, Islas Canarias, Spain. UAH, Dept Phys, Huntsville, AL 35899 USA. RP Groot, PJ (reprint author), CHEAF, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. EM pgroot@cfa.harvard.edu RI Groot, Paul/K-4391-2016 OI Groot, Paul/0000-0002-4488-726X NR 36 TC 25 Z9 25 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2001 VL 368 IS 1 BP 183 EP 196 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 421GZ UT WOS:000168057800016 ER PT J AU de Jong, JA Henrichs, HF Kaper, L Nichols, JS Bjorkman, K Bohlender, DA Cao, H Gordon, K Hill, G Jiang, Y Kolka, I Morrison, N Neff, J O'Neal, D Scheers, B Telting, JH AF de Jong, JA Henrichs, HF Kaper, L Nichols, JS Bjorkman, K Bohlender, DA Cao, H Gordon, K Hill, G Jiang, Y Kolka, I Morrison, N Neff, J O'Neal, D Scheers, B Telting, JH TI A search for the cause of cyclical wind variability in O stars - Simultaneous UV and optical observations including magnetic field measurements of the O7.5III star epsilon Persei SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars; early-type; atmospheres; winds, outflows; magnetic fields ID COROTATING INTERACTION REGIONS; SHORT-TERM VARIABILITY; IUE MEGA CAMPAIGN; STELLAR WIND; TIME-SERIES; MASS-LOSS; ABSORPTION COMPONENTS; XI-PERSEI; H-ALPHA; SPECTRA AB We present the results of an extensive observing campaign on the 07.5 III star xi Persei. The UV observations were obtained with the International Ultraviolet. Explorer. xi Per was monitored continuously in October 1994 during 10 days at ultraviolet and visual wavelengths. The ground-based optical observations include magnetic field measurements, H alpha and He I lambda 6678 spectra, and were partially covered by photometry and polarimetry. We describe a method to automatically remove the variable contamination of telluric lines in the groundbased spectra. The aim of this campaign was to search for the origin of the cyclical wind variability in this star. We determined a very accurate period of 2.086(2) d in the resonance lines of Si IV and in the subordinate N IV and Ha line profiles. The epochs of maximum absorption in the UV resonance lines due to discrete absorption components (DACs) coincide in phase with the maxima in blue-shifted H alpha absorption. This implies that the periodic variability originates close to the stellar surface. The phase-velocity relation shows a maximum at -1400 km s(-1) The general trend of these observations can be well explained by the corotating interaction region (CIR) model. In this model the wind is perturbed by one or more fixed patches: on the stellar surface, which are most probably due to small magnetic field structures. Our magnetic field measurements gave however, only a null-detection with a 1 sigma errorbar of 70 G in the longitudinal component. Some observations are more difficult to fit into this picture. The 2-day period is not detected in the photospheric/transition region line He I lambda 6678. The dynamic spectrum of this line shows a pattern indicating the presence of non-radial pulsation, consistent with the previously reported period of 3.5 h. The edge variability around -2300 km s(-1) in the saturated wind lines of C IV and N V is nearly identical to the edge variability in the unsaturated Si rv Line, supporting the view that this: type of variability is also due to the moving DACs. A detailed analysis using Fourier reconstructions reveals that each DAC actually consists of 2 different components: a "fast" and a "slow" one which merge at higher velocities. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Leiden Univ, Leiden Observ, NL-2333 CA Leiden, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Toledo, Ritter Astrophys Res Ctr, Toledo, OH 43606 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7, Canada. Beijing Astron Observ, Beijing 100012, Peoples R China. Univ Arizona, Steward Observ, Tucson, AZ 85712 USA. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Tartu Observ, F-61602 Toravere, Estonia. Coll Charleston, Dept Phys & Astron, Charleston, SC 29424 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. NWO, Netherlands Org Sci Res, Isaac Newton Grp Telescopes, Santa Cruz de La Palma 38700, Spain. RP Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. EM jdj@astro.uva.nl NR 38 TC 47 Z9 50 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2001 VL 368 IS 2 BP 601 EP 621 DI 10.1051/0004-6361:20000570 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 425RV UT WOS:000168306200023 ER PT J AU Huang, JS Thompson, D Kummel, MW Meisenheimer, K Wolf, C Beckwith, SVW Fockenbrock, R Fried, JW Hippelein, H von Kuhlmann, B Phelps, S Roser, HJ Thommes, E AF Huang, JS Thompson, D Kummel, MW Meisenheimer, K Wolf, C Beckwith, SVW Fockenbrock, R Fried, JW Hippelein, H von Kuhlmann, B Phelps, S Roser, HJ Thommes, E TI The Calar Alto Deep Imaging Survey: K-band galaxy number counts SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE cosmology : observations; galaxies : evolution; galaxy : formation; surveys; infrared : galaxies ID STAR-FORMING GALAXIES; SOUTH GALACTIC POLE; REDSHIFT SURVEY; LUMINOSITY FUNCTION; SPECTRAL EVOLUTION; FAINT GALAXIES; FIELD; COLORS; SPECTROSCOPY; ULTRAVIOLET AB We present K-band number counts for the faint galaxies in the Calar Alto Deep Imaging Survey (CADIS). We covered 4 CADIS fields, a total area of 0.2 deg(2), in the broad band filters B, R and K. We detect about 4000 galaxies in the K-band images, with a completeness limit of K = 19.75 mag, and derive the K-band galaxy number counts in the range of 14.25 < K < 19.75 mag. This is the largest medium deep K-band survey to date in this magnitude range. The B- and R-band number counts are also derived, down to completeness limits of B = 24.75 mag and R = 23.25 mag. The K-selected galaxies in this magnitude range are of particular interest, since some medium deep near-infrared surveys have identified breaks of both the slope of the K-band number counts and the mean B - K color at K = 17 similar to 18 mag. There is, however, a significant disagreement in the K-band number counts among the existing surveys. Our large near-infrared selected galaxy sample allows us to establish the presence of a clear break in the slope at K = 17.0 mag from dlog N/dm = 0.64 at brighter magnitudes to dlog N/dm = 0.36 at the fainter end; We construct no-evolution and passive evolution models, and find that the passive evolution model can simultaneously fit the B-, R- and K-band number counts well. The B - K colors show a clear trend to bluer colors for K > 18 mag. We also find that most of the K = 18-20 mag galaxies have a B - K color bluer than the prediction of a no-evolution model for an L* Sbc galaxy, implying either significant evolution, even for massive galaxies, or the existence of an extra population of small galaxies. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. RP Huang, JS (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM jhuang@cfa.harvard.edu NR 55 TC 49 Z9 50 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2001 VL 368 IS 3 BP 787 EP 796 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 421PH UT WOS:000168072400012 ER PT J AU Mewe, R Raassen, AJJ Drake, JJ Kaastra, JS van der Meer, RLJ Porquet, D AF Mewe, R Raassen, AJJ Drake, JJ Kaastra, JS van der Meer, RLJ Porquet, D TI CHANDRA-LETGS X-ray observations of Capella - Temperature, density and abundance diagnostics SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : individual : Capella; stars : coronae; stars : late-type; stars : activity; X-rays : stars; atomic processes vspace-1mm ID TRANSMISSION GRATING SPECTROMETER; FE-XVII; CORONAL STRUCTURE; SOLAR; STARS; LINES; SPECTRUM; SPECTROSCOPY; LOOPS; EUVE AB We report an analysis of the X-ray spectrum of Capella from 6 to 175 Angstrom obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board of the X-ray space observatory CHANDRA. Many emission line features appear that can be resolved much better as compared to former instruments (EUVE and ASCA). Coronel electron densities (n(e)) and temperatures (T) of brightly emitting regions are constrained by an analysis of ratios of density- and temperature-sensitive lines of helium-like ions and highly ionized iron atoms. Lines emitted by e.g., O VII & VIII, Mg X-XII, Si XII-XIV, Fe IX, X & XV-XXIII are used to derive T. Line ratios in the helium-like triplets of C V, N VI, O VIE, Mg XI, and Si XIII yield T in the range 0.5-10 MK, and n(e) in the range 10(9)-10(13) cm(-3). The Fe IX/X ratio yields T similar or equal to 0.9 MK, while lines from Fe XVIII to XXII give T similar to 6-10 MK. Flux ratios of Fe XX-XXII lines indicate for the electron densities an upper limit in the range n(e) less than or similar to (2-5) 10(12) cm(-3). From line ratios of Fe XVII and Fe XVIII we derive constraints on the optical depth tau of similar to1-1.5. An emission measure distribution is derived from Fe line intensities. Results for element abundances (relative to Fe) from a 4-T model are: O and Ne/Fe about solar, N, Mg and Si/Fe similar to 2x solar. The results for T and n(e) are described in terms of quasi-static coronal loop models and it is shown that the X-fay emission originates from compact structures much smaller than the stellar radii. C1 SRON, NL-3584 CA Utrecht, Netherlands. Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. CEA, Serv Astrophys, DAPNIA, DSM, F-91191 Gif Sur Yvette, France. RP SRON, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands. EM R.Mewe@sron.nl OI Porquet, Delphine/0000-0001-9731-0352 NR 37 TC 74 Z9 74 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2001 VL 368 IS 3 BP 888 EP 900 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 421PH UT WOS:000168072400021 ER PT J AU Kervella, P du Foresto, VC Perrin, G Scholler, M Traub, WA Lacasse, MG AF Kervella, P du Foresto, VC Perrin, G Scholler, M Traub, WA Lacasse, MG TI The angular diameter and distance of the Cepheid zeta Geminorum SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : distances; stars : individual : zeta Gem; stars : oscillations; stars : Cepheids; techniques : interferometric ID FUNDAMENTAL PARAMETERS; IOTA INTERFEROMETER; STELLAR PULSATIONS; GALACTIC CEPHEIDS; HR DIAGRAM; SPECTRA; RADII; CALIBRATION; SCALE; BAND AB Cepheids are the primary distance indicators for extragalactic astronomy and therefore are of very high astrophysical interest. Unfortunately, they are rare stars, situated very far from Earth. Though they are supergiants, their typical angular diameter is only a few milliareseconds, making them very challenging targets even for long-baseline interferometers. We report observations that were obtained in the K' band (2-2.3 mum), on the Cepheid zeta Geminorum with the FLUOR beam combiner, installed at the IOTA interferometer. The mean uniform disk angular diameter was measured to be 1.64 +/-0.14 0.16 mas. Pulsational variations are not detected at a significant statistical level, but future observations with longer baselines should allow a much better estimation of their amplitude. The distance to zeta Gem is evaluated using Baade-Wesselink diameter determinations, giving a distance of 502 +/- 88 pc. C1 European So Observ, D-85748 Garching, Germany. Observ Paris, F-92195 Meudon, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kervella, P (reprint author), European So Observ, Karl Schwarzschildstr 2, D-85748 Garching, Germany. EM pkervell@eso.org NR 40 TC 33 Z9 33 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2001 VL 367 IS 3 BP 876 EP 883 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 419FG UT WOS:000167938200017 ER PT J AU Wilkes, BJ Mathur, S Fiore, F Antonelli, A Nicastro, F AF Wilkes, BJ Mathur, S Fiore, F Antonelli, A Nicastro, F TI BeppoSAX observations of the maser Seyfert 2 galaxy ESO 103-G35 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (ESO 103-G35); galaxies : nuclei; galaxies : Seyfert; X-rays : galaxies; masers ID ACTIVE GALACTIC NUCLEI; X-RAY SAMPLE; ESO 103-G35; ASCA OBSERVATIONS; ABSORPTION; NGC-4258; SPECTRUM; MODEL AB We have made BeppoSAX observations of the Seyfert 2/1.9 galaxy ESO 103-G35, which contains a nuclear maser source and is known to be heavily absorbed in the X-rays. Analysis of the X-ray spectra observed by BeppoSAX in 1996 October and 1997 October yields a spectral index alpha (E) = 0.74 +/- 0.07 (F(v) proportional to v(-alphaE)), which is typical of Seyfert galaxies and consistent with earlier observations of this source. The strong, soft X-ray absorption has a column density N(H) of 1.79 +/- 0.09 x 10(23) cm(-2), again consistent with earlier results. The best-fitting spectrum is that of a power law with a high-energy cutoff at 29 +/- 10 keV, a cold (E = 6.3 +/- 0.1 keV, rest frame), marginally resolved (sigma = 0.35 +/- 0.14 keV, FWHM similar to 31 +/- 12 x 10(3) km s(-1)) Fe K alpha line with EW 290(-80)(+100) eV (1996), and a mildly ionized Fe K edge at 7.37(-0.21)(+0.15) keV, tau = 0.24(-0.09)(+0.06). The K alpha line and cold absorption are consistent with origin in an accretion disk/torus through which our line of sight passes at a radial distance of similar to 50 pc. The Fe K edge is mildly ionized, suggesting the presence of ionized gas, probably in the inner accretion disk close to the central source or in a separate warm absorber. The data quality is too low to distinguish between these possibilities, but the edge-on geometry implied by the water maser emission favors the former. Comparison with earlier observations of ESO 103-G35 shows little or no change in spectral parameters while the flux changes by factors of a few on timescales of a few months. The 2-10 keV flux decreased by a factor of similar to2.7 between 1996 October and 1997 October with no detectable change in the count rate greater than 20 keV (i.e., the Phoswich Detector System data). Spectral fits to the combined data sets indicate either a significant hardening of the spectrum (alpha (E) similar to 0.5) or an approximately constant or delayed response reflection component. The high-energy cutoff (29 +/- 10 keV) is lower than the typical similar to 300 keV values seen in Seyfert galaxies. A significant subset of similar sources would affect current models of the active galactic nucleus contribution to the cosmic X-ray background which generally assume a high-energy cutoff of similar to 300 keV. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Ohio State Univ, Columbus, OH 43210 USA. BeppoSAX Sci Data Ctr, I-00131 Rome, Italy. Osserv Astron Roma, I-00040 Monte Porzio Catone, Italy. RP Wilkes, BJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Nicastro, Fabrizio/0000-0002-6896-1364; Wilkes, Belinda/0000-0003-1809-2364; Fiore, Fabrizio/0000-0002-4031-4157 NR 23 TC 11 Z9 11 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2001 VL 549 IS 1 BP 248 EP 253 DI 10.1086/319063 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413DG UT WOS:000167594200019 ER PT J AU Navascues, DBY Deliyannis, CP Stauffer, JR AF Navascues, DBY Deliyannis, CP Stauffer, JR TI WIYN open cluster study. V. Lithium depletion and metallicity in G and K dwarfs of the open cluster M35 SO ASTROPHYSICAL JOURNAL LA English DT Article DE open clusters and associations : individual (M35,NGC 2168); stars : abundances; stars : evolution; stars : late-type ID SOLAR-TYPE STARS; LOW-MASS STARS; CHROMOSPHERICALLY ACTIVE BINARIES; YOUNG OPEN CLUSTERS; AGE MAIN-SEQUENCE; STELLAR EVOLUTION; PRECISE DETERMINATION; ABUNDANCE DISPERSION; KECK SPECTRA; HALO STARS AB We present an analysis of high-quality spectra of members of the young cluster M35. By using a multifiber spectrograph, we are able to collect high signal-to-noise ratio, high-resolution spectra of a sample of photometric candidate members. Accurate radial velocities are used to establish the membership status, and rotational velocities are measured using cross-correlation. We also derive the metal content of the cluster, [Fe/H](M35) = -0.21 +/- 0.10, based on spectral synthesis. Finally, we derive the lithium abundances of the bona fide cluster members and compare the results with members of other clusters. For example, M35 shows a smaller range in both rotation rates and lithium abundances as compared to the Pleiades. We discuss possible roles of various parameters. Our high-quality M35 data-base of lithium abundances and rotational velocities is perfectly suited to be used as a laboratory to test theoretical models dealing with the lithium depletion phenomenon. We discuss the role of stellar inhomogeneities and rotation on the lithium depletion phenomenon. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Indiana Univ, Dept Astron, Bloomington, IN 47405 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Navascues, DBY (reprint author), Univ Autonoma Madrid, Dept Fis Teor, C-XI, E-28049 Madrid, Spain. RI Barrado Navascues, David/C-1439-2017 OI Barrado Navascues, David/0000-0002-5971-9242 NR 84 TC 34 Z9 34 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2001 VL 549 IS 1 BP 452 EP 466 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413DG UT WOS:000167594200037 ER PT J AU Menou, K Perna, R Raymond, JC AF Menou, K Perna, R Raymond, JC TI X-ray lines from hot flows around white dwarfs: Application to SS Cygni SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; white dwarfs; X-rays : stars ID DIELECTRONIC SATELLITE SPECTRA; ADVECTION-DOMINATED ACCRETION; DISK BOUNDARY-LAYERS; NOVA HT-CASSIOPEIAE; HELIUM-LIKE IONS; CATACLYSMIC VARIABLES; BLACK-HOLES; RATE COEFFICIENTS; EMISSION; EXCITATION AB Rather than accreting via a disk, some white dwarfs (WDs) in quiescent dwarf novae (DN) could accrete via an advection-dominated accretion flow (ADAF) possibly responsible for the X-ray bremsstrahlung emission observed. Such a hot accretion flow is also expected to produce characteristic thermal line emission. Using SS Cyg as a specific example, we show that knowing a priori the inclination and the WD mass in quiescent DN makes X-ray line diagnostics powerful probes of the flow structure in these systems. Current X-ray instruments can discriminate, from their width, between lines emitted from a flow with a Keplerian rotation rate and those emitted at a substantially sub-Keplerian rate. This could be used to observationally test the property of energy advection, which is at the origin of the partial radial pressure support by the hot gas and the sub-Keplerian rotation rate in an ADAF. C1 Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Menou, K (reprint author), Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. NR 49 TC 3 Z9 3 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 MAR 1 PY 2001 VL 549 IS 1 BP 509 EP 515 DI 10.1086/319074 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413DG UT WOS:000167594200041 ER PT J AU Vrtilek, SD Quaintrell, H Boroson, B Still, M Fiedler, H O'Brien, K McCray, R AF Vrtilek, SD Quaintrell, H Boroson, B Still, M Fiedler, H O'Brien, K McCray, R TI Multiwavelength studies of hercules X-1 during short high and anomalous low states: On-again, off-again SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; pulsars : individual (Hercules X-1); ultraviolet : stars; X-rays : stars ID X-RAY BINARIES; TELESCOPE IMAGING SPECTROGRAPH; EXTREME-ULTRAVIOLET EXPLORER; ALL-SKY MONITOR; ACCRETION DISKS; CLOCK MECHANISM; TIMING-EXPLORER; 35-DAY CYCLE; PULSE-PHASE; HZ-HERCULIS AB We present results from multiwavelength observations of the Hercules X-1 system during a short high state (SHS) and during an anomalous low state (ALS). The magnitude of deviation from spin-up appears to be positively correlated with duration of the ALS. Such a correlation is consistent with an interpretation of the ALS in terms of a change in mass accretion rate that causes the disk to tilt and twist beyond the normal deviations that cause the 35 day cycle. A larger deviation from the average (M)over dot results in a stronger disruption of the disk and causes the disk to take longer to settle back to its "normal" 35 day behavior. Our model-which includes X-ray heating of the disk and companion star, shadowing of the X-ray flux by the disk, and a contribution to the continuum emission from the accretion stream or hot spot-can consistently explain the observed changes in X-ray, ultraviolet (UV), and optical continuum light curves for both the SHS and ALS. The Hubble Space Telescope (HST) and Space Telescope Imaging Spectrograph (STIS) observations presented here are the first UV observations of sufficient spectral and temporal resolution to construct Doppler tomograms of the line emission. Doppler tomograms of the UV emission lines during SHS and ALS show the majority of the emission coming from the surface of the companion star rather than from the accretion disk. Tomograms made after separating the N V emission lines into broad and narrow components suggests that while the narrow component is associated with emission from the companion star, the broad component may be associated with emission from a distorted disk. The Doppler maps also show that heating over the inner face of HZ Her is not uniform and imply partial eclipse of the UV line emission by an accretion stream and/or hot spot. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Open Univ, Milton Keynes MK7 6AA, Bucks, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Munich, Univ Sternwarte Munchen, D-81679 Munich, Germany. Univ St Andrews, St Andrews KY16 9SS, Fife, Scotland. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RP Vrtilek, SD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 64 TC 19 Z9 19 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 MAR 1 PY 2001 VL 549 IS 1 BP 522 EP 536 DI 10.1086/319071 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413DG UT WOS:000167594200043 ER PT J AU Ayres, TR Brown, A Osten, RA Huenemoerder, DP Drake, JJ Brickhouse, NS Linsky, JL AF Ayres, TR Brown, A Osten, RA Huenemoerder, DP Drake, JJ Brickhouse, NS Linsky, JL TI Chandra, EUVE, HST, and VLA multiwavelength campaign on HR 1099: Instrumental capabilities, data reduction, and initial results SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : coronae; stars : individual (HR 1099); ultraviolet : stars; X-rays : stars ID RS CANUM-VENATICORUM; HIGH-RESOLUTION SPECTROGRAPH; V711 TAURI; TRANSITION REGION; ROTATIONAL MODULATION; EXPLOSIVE EVENTS; MAGNETIC-FIELDS; SYSTEM HR-1099; FE-XXI; STARS AB In mid-September of 1999, a multiwavelength campaign was carried out on the coronally active RS Canum Venaticorum binary HR 1099 (K1 IV + G5 V; P = 2.84 days), during commissioning of the High Energy Transmission Grating Spectrometer (HETGS) of the Chandra X-ray Observatory (CXO). The coordinated program involved the Extreme Ultraviolet Explorer (EUVE), the Hubble Space Telescope Imaging Spectrograph (STIS), and the Very Large Array (VLA). The objective was to study the system in quiescence, across as much of the electromagnetic spectrum as practical, and to catch any flares that might occur. The EUVE 80-180 Angstrom light curve of HR 1099, covering the period September 13-22, showed only a single impulsive outburst, which occurred at the very end of the 9 day pointing. The 3-25 Angstrom bremsstrahlung continuum displayed an overall decay during the 1.5 day Chandra observation on September 14-16, with a few superimposed mild enhancements. The VLA 3.5 cm and 20 cm radio light curves, obtained during a 10 hr period on September 15 immediately before the HST pointing, similarly revealed normal quiescent gyrosynchrotron emission and an absence of impulsive events. In contrast, the 7 hr STIS time series later on September 15 contained two distinct flares. The first was accompanied by intensification of the preexisting broad wings of the medium excitation species (e.g., Si IV lambda 1393 and C IV lambda 1548), while the second involved primarily the narrow cores of the lines, and even cooler temperatures. The Fe XXI lambda 1354 forbidden line showed little response to either flare, consistent with the contemporaneous soft X-ray and EUV light curves. The lack of coronal counterparts to the ultraviolet flares is unusual and suggests that they belong to a separate class of outbursts, sharing some similarities with the "transition zone explosive events" seen on the Sun. The density sensitive O IV lambda 1400 multiplet was not affected by either flare. The density sensitive Si III lambda 1300 multiplet showed little response to the first flare, but a dramatic brightening in the second, likely due to the lower peak temperature of that event. The O IV line ratios were near their low-density limits and suggest n(e) similar to 10(10) cm(-3) for the duration of the HST observations. The Si III ratios during the second flare rise indicate n(e) similar to 7 x 10(10) cm(-3). The far-UV diagnostics jointly imply electron pressures of n(e) T similar to 2 x 10(15) K cm(-3), if formed close to their respective ionization equilibrium temperatures. The helium-like triplets of O VII, NeIX, and Mg XI in the HETGS spectra have forbidden-tointercombination line ratios consistent with average coronal electron densities of less than or similar to 10(11) cm(-3) at T similar to 0.3-1 x 10(7) K over the duration of the Chandra pointing. Fe XXI lambda 102/lambda 128 and lambda 142/lambda 128 ratios from EUVE suggest n(e) less than or similar to 10(12)-10(13) cm(-3), near 10(7) K. Thus, the coronal electron pressures could be as much as several orders of magnitude larger than those of the lower atmosphere. We constructed time-resolved spectra from the HETGS event lists and measured the centroids of the three brightest X-ray lines of HR 1099 in 60 minute bins. In high-S/N Ne x lambda 12.1, we believe that we can see the changing radial velocity of the K1 IV star over the half an orbital cycle recorded by Chandra. The amplitude of the velocity change is only similar to 100 km s(-1) over the 1.5 day interval, a small fraction of the 300-500 km s(-1) resolution of the HETGS at 12 Angstrom. Ne x lambda 12.1 also displayed a transient blueshift of similar to 60 km s(-1) immediately prior to the first STIS flare, during which the far-UV lines briefly exhibited blueshifts of similar magnitude. The apparent displacement of Ne x appears independently in the -1 and +1 orders of the medium energy band (MEG), but there was no confirmation in the redundant high energy band (HEG), nor in other X-ray lines. Fe XXI lambda 1354 showed a blueshift about 30 minutes later at the beginning of the second HST orbit, but only at the 20 km s(-1) level. Analogous HETGS time series of the brightest lines of comparison star Capella (alpha Aurigae; G8 III + G1 III) exhibited steady behavior, consistent with measurement uncertainties, without the transient Doppler "bursts" seen in HR 1099. Although the reality of the Ne x Ly alpha blueshift is in doubt, there is no question that the Chandra HETGS velocity scales are stable and free from large systematic errors. C1 Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RP Ayres, TR (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, 389 UCB CASA, Boulder, CO 80309 USA. OI Brickhouse, Nancy/0000-0002-8704-4473 NR 87 TC 68 Z9 68 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 MAR 1 PY 2001 VL 549 IS 1 BP 554 EP 577 DI 10.1086/319051 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 413DG UT WOS:000167594200045 ER PT J AU Vikhlinin, A Markevitch, M Murray, SS AF Vikhlinin, A Markevitch, M Murray, SS TI Chandra estimate of the magnetic field strength near the cold front in A3667 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : clusters : individual (Abell 3667); magnetic fields; X rays : galaxies ID CLUSTERS; GALAXIES; GAS AB We use the Chandra observation of the cold front in the intracluster gas of A3667 to estimate the magnetic field strength near the front. The front is seen in the Chandra data as a sharp discontinuity in the gas density that delineates a large body of dense cool gas moving with near-sonic velocity through the less dense, hotter gas. Without a magnetic field, the front should be quickly disturbed by the Kelvin-Helmholtz instability arising from tangential motion of gas layers. However, the Chandra image shows that the front is stable within a +/-30 degrees sector in the direction of the cloud motion, beyond which it gradually disappears. We suggest that the Kelvin-Helmholtz instability within the +/-30 degrees sector is suppressed by the surface tension of the magnetic field whose field lines are parallel to the front. The required field strength is B similar to 10 muG. The magnetic field near the front is expected to be stronger and to have a very different structure compared with the bulk of the intergalactic medium because the field lines are stretched by the tangential gas motions. Such a magnetic configuration, once formed, would effectively stop the plasma diffusion and heat conduction across the front and may inhibit gas mixing during the subcluster merger. We note that even the increased magnetic field near the front contributes only 10%-20% to the total gas pressure, and therefore magnetic pressure is unimportant for hydrostatic cluster mass estimates. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Moscow Space Res Inst, Moscow 117810, Russia. RP Vikhlinin, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 20 TC 119 Z9 119 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 MAR 1 PY 2001 VL 549 IS 1 BP L47 EP L50 DI 10.1086/319126 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 406HK UT WOS:000167208700011 ER PT J AU Bonnet, X Lagarde, F Henen, BT Corbin, J Nagy, KA Naulleau, G Balhoul, K Chastel, O Legrand, A Cambag, R AF Bonnet, X Lagarde, F Henen, BT Corbin, J Nagy, KA Naulleau, G Balhoul, K Chastel, O Legrand, A Cambag, R TI Sexual dimorphism in steppe tortoises (Testudo horsfieladii): influence of the environment and sexual selection on body shape and mobility SO BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY LA English DT Article DE body shape; sexual dimorphism; sexual selection; Testudo; tortoises; Uzbekistan ID SIZE DIMORPHISM; GOPHERUS-AGASSIZII; DESERT TORTOISES; EVOLUTION; SNAKES; POPULATIONS; ALLOMETRY; ABUNDANCE; PROXIMATE; ANIMALS AB Selective forces shape sexes differently, with male body proportions facing strong selection to enhance mate searching and male-to-male combat traits, and female fitness being influenced by the ability to assimilate large amounts of nutrients necessary for vitellogenesis (and/or gestation), and their ability to carry the eggs or embryos. We evaluated the sexual dimorphism of body proportion of more than 800 wild steppe tortoises (Testudo horsfieldii) in Uzbekistan. The thick, well-developed shell offers protection from predators but pronounced digging habits probably also constrain body shape (e.g. a shell that is dorso-ventrally flattened, although round from a dorsal view helps to penetrate into, and move within the soil). Thus, in this species, natural selection might favour a heavy and flat shell that is 'closed' with small openings for appendages. In males, these environmental influences appear to be countered by sexual selection. Compared to females, they weigh less (absolutely and relative to shell dimensions), have longer legs, have shell structure allowing wider movements for their legs, and they walk faster. Males were also able to right themselves more quickly than females did in experimental tests. This quick righting ability is critical because intra-sexual combats frequently result in males being flipped onto their backs and becoming prone to hyperthermia or predation. Females are heavily built, with wide shells (relative to male shells), which may provide space for carrying eggs. From our results, a number of simple hypotheses can be tested on a wide range of chelonian species. (C) 2001 The Linnean Society of London. C1 CNRS, CEBC, Conseil Gen Deux Sevres, F-79360 Villiers En Bois, France. Univ Rochelle, Dept Biol, F-17000 La Rochelle, France. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. Univ Calif Los Angeles, Dept Organism Biol Ecol & Evolut, Los Angeles, CA 90095 USA. RP Bonnet, X (reprint author), CNRS, CEBC, Conseil Gen Deux Sevres, F-79360 Villiers En Bois, France. RI Henen, Brian/S-6552-2016 OI Henen, Brian/0000-0003-3412-4944 NR 77 TC 66 Z9 67 U1 3 U2 24 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0024-4066 J9 BIOL J LINN SOC JI Biol. J. Linnean Soc. PD MAR PY 2001 VL 72 IS 3 BP 357 EP 372 DI 10.1006/bjls.2000.0504 PG 16 WC Evolutionary Biology SC Evolutionary Biology GA 423PZ UT WOS:000168187100002 ER PT J AU Jarken, E Zheng, XW AF Jarken, E Zheng, XW TI Does the masing gas fall inward VYCMa? SO CHINESE PHYSICS LETTERS LA English DT Article ID VY-CANIS-MAJORIS; WATER; EMISSION; STARS AB The water maser emission from the unusual supergiant, VY CMa, has been observed with the Urumqi 25m radio telescope. A simple redshifted maser spectrum was detected in the 1.6 Jy noise level during our monitoring observations. All of the H2O maser features are redshifted with respect to the VY CMa stellar velocity of I 7.6 km .s(-1). The spectrum appears to consist of two striking like groups and each group has three features. The appearances and the ratio of these three features in the two maser groups are very similar. The H2O maser emission arises from a region close to the supergiant, about 10 stellar radii of the star. The simple redshifted spectrum could be due to infall masing gas on the near side of the disk. Pulsation of the central star causes oscillations in this portion of the envelope, with the shock wave propagating outward and with material falling inward. The masing gas motions are very complex, by which the dramatic changes or the quasi-sinusoidal fluctuation in Aux may be explained. C1 Chinese Acad Sci, Urumqi Astron Observ, Urumqi 830011, Peoples R China. Nanjing Univ, Dept Astron, Nanjing 210093, Peoples R China. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Jarken, E (reprint author), Chinese Acad Sci, Urumqi Astron Observ, Urumqi 830011, Peoples R China. RI Lin, Aoxiang/C-9978-2009 NR 12 TC 0 Z9 0 U1 0 U2 1 PU ALLERTON PRESS INC PI NEW YORK PA 18 WEST 27TH ST, NEW YORK, NY 10001 USA SN 0256-307X J9 CHINESE PHYS LETT JI Chin. Phys. Lett. PD MAR PY 2001 VL 18 IS 3 BP 458 EP 460 PG 3 WC Physics, Multidisciplinary SC Physics GA 417RM UT WOS:000167848000050 ER PT J AU Grativol, AD Ballou, JD Fleischer, RC AF Grativol, A. D. Ballou, J. D. Fleischer, R. C. TI Microsatellite variation within and among recently fragmented populations of the golden lion tamarin (Leontopithecus rosalia) SO CONSERVATION GENETICS LA English DT Article DE conservation genetics; endangered species; genetic management; microsatellite primers; Leontopithecus AB Four variable microsatellite loci were used to examine the genetic diversity and differentiation of golden lion tamarins (Leontopithecus rosalia) in four populations recently isolated by habitat fragmentation. Using Rst estimates of genetic differentiation, a considerable genetic divergence was detected among these populations, with an average differentiation of 31%. Significant differences in allele number among these populations were found. However, the heterozygosity among these populations was not statistically different. These results suggest that loss in allele diversity was faster than loss in heterozygosity. Conservation implications, particularly for golden lion tamarins, are then discussed. Loss of allelic diversity might be as serious a concern to endangered species as heterozygosity or inbreeding. C1 [Grativol, A. D.; Ballou, J. D.; Fleischer, R. C.] Smithsonian Inst, Natl Zool Pk, Washington, DC 20008 USA. [Grativol, A. D.] American Univ, Dept Biol, Washington, DC 20016 USA. RP Grativol, AD (reprint author), Univ Estadual Norte Fluminense, Lab Ciencias Ambientais, Rua Alberto Lamego 2000, BR-28015620 Campos Dos Goytacazes, RJ, Brazil. EM ADG@ROL.COM.BR FU Smithsonian Institution Latino Initiative FX We thank D. Kleiman, J. Dietz, A. Baker, C. Kierulf, P. Oliveira, and C. Ruiz-Miranda for logistic assistance and/or samples. A. Grativol was supported by a Smithsonian Institution Latino Initiative Fellowship. Fieldwork was generously supported by the World Wildlife Fund-Brasil. Supply expenses were provided by the Smithsonian Institution and Friends of the National Zoo. We thank C. Schaeff and three anonymous referees for their helpful comments on an earlier draft of the manuscript. NR 40 TC 38 Z9 39 U1 3 U2 28 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1566-0621 J9 CONSERV GENET JI Conserv. Genet. PD MAR PY 2001 VL 2 IS 1 BP 1 EP 9 DI 10.1023/A:1011543401239 PG 9 WC Biodiversity Conservation; Genetics & Heredity SC Biodiversity & Conservation; Genetics & Heredity GA V22NN UT WOS:000208282000001 ER PT J AU Barbosa, P Segarra, AE Gross, P Caldas, A Ahlstrom, K Carlson, RW Ferguson, DC Grissell, EE Hodges, RW Marsh, PM Poole, RW Schauff, ME Shaw, SR Whitfield, JB Woodley, NE AF Barbosa, P Segarra, AE Gross, P Caldas, A Ahlstrom, K Carlson, RW Ferguson, DC Grissell, EE Hodges, RW Marsh, PM Poole, RW Schauff, ME Shaw, SR Whitfield, JB Woodley, NE TI Differential parasitism of macrolepidopteran herbivores on two deciduous tree species SO ECOLOGY LA English DT Article DE Acer negundo; black willow; box elder; differential parasitism; insect assemblages; Lepidoptera; macrolepidoptera; niche-specificity; parasitoids; plant influences on parasitism; Salix nigra ID HOST; HYMENOPTERA; SELECTION; PATTERNS; LARVAE; PLANTS; BRACONIDAE; VOLATILES; BEHAVIOR; HABITAT AB Patterns of larval parasitism among species in the macrolepidopteran assemblages on two riparian tree species, Acer negundo L. (box elder) and Salix nigra (Marsh) (black willow) were examined. Larvae were collected throughout the growing season for five years and reared for parasitoid emergence. Total parasitism of larvae on box elder was significantly higher than that of larvae on black willow. Comparisons of parasitism levels among lepidopteran families showed that in five of seven families larval parasitism on box elder was significantly higher than on black willow. For species whose larvae were found on both tree species, total parasitism was significantly higher when the larvae were on box elder than when larvae of the same species were on black willow. In comparisons of species found on both tree species, larvae in three of seven families suffered significantly higher levels of parasitism when on box elder than when on black willow. The roles of the functional/numerical responses of parasitoids, common and numerically dominant parasitoid species, and plant volatiles are considered as causal mechanisms underlying differential parasitism but are not supported by the data. C1 Univ Maryland, Dept Entomol, College Pk, MD 20742 USA. Natl Louis Univ, Evanston, IL 60201 USA. N Carolina Dept Agr, Div Plant Ind, Raleigh, NC 27611 USA. Commun & Taxon Serv Unit, Systemat Entomol Lab, Beltsville, MD 20705 USA. Smithsonian Inst, Natl Museum Nat Hist, Systemat Entomol Lab, Washington, DC 20560 USA. Entomol Informat Serv, Rockville, MD 20849 USA. Univ Wyoming, Dept Plant Soil & Insect Sci, Laramie, WY 82071 USA. Univ Arkansas, Dept Entomol, Fayetteville, AR 72701 USA. RP Barbosa, P (reprint author), Univ Maryland, Dept Entomol, College Pk, MD 20742 USA. RI Woodley, Norman/M-6160-2014 NR 51 TC 34 Z9 36 U1 0 U2 3 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 0012-9658 EI 1939-9170 J9 ECOLOGY JI Ecology PD MAR PY 2001 VL 82 IS 3 BP 698 EP 704 DI 10.1890/0012-9658(2001)082[0698:DPOMHO]2.0.CO;2 PG 7 WC Ecology SC Environmental Sciences & Ecology GA 405BW UT WOS:000167138200007 ER PT J AU Krijger, CL Sevenster, JG AF Krijger, CL Sevenster, JG TI Higher species diversity explained by stronger spatial aggregation across six neotropical Drosophila communities SO ECOLOGY LETTERS LA English DT Article DE aggregation model; community stability; disturbance; fragmented resources; interspecific competition; local diversity; saturation ID EPHEMERAL RESOURCE; COMPETITIVE-EXCLUSION; PATCHY ENVIRONMENT; SIMULATION-MODEL; COEXISTENCE; DIPTERA; SIZE AB Spatial aggregation of competitors over resource patches is generally accepted as an important mechanism maintaining coexistence of species in insect communities exploiting fragmented resources. However, its quantitative effects on local diversity, i.e. the relationship between the degree of aggregation in a community and community diversity, remain unexplored. In this paper, we tested whether stronger spatial aggregation does lead to the predicted higher local diversity. We compared six species rich Drosophila communities exploiting decaying fruits in central Panama, monitored over one full year (>25 generations). We found a clear positive relationship between the overall degree of aggregation and community diversity. In addition, aggregation over fruit trees was found to contribute greatly to the overall degree of aggregation and was largely responsible for the observed relationship between aggregation and diversity across communities. In addition, both diversity and aggregation strength were lower in communities in disturbed habitats, which was explained by altered spatial distribution of fruiting trees. This study. shows that the aggregation model cannot only explain coexistence, but also differences in local diversity. C1 Leiden Univ, Inst Evolutionary & Ecol Sci, Sect Anim Ecol, NL-2300 RA Leiden, Netherlands. Panama STRI, Smithsonian Trop Res Inst, Balboa, Panama. RP Krijger, CL (reprint author), Leiden Univ, Inst Evolutionary & Ecol Sci, Sect Anim Ecol, POB 9516, NL-2300 RA Leiden, Netherlands. EM krijger@rulsfb.leidenuniv.nl NR 47 TC 33 Z9 35 U1 2 U2 9 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1461-023X J9 ECOL LETT JI Ecol. Lett. PD MAR PY 2001 VL 4 IS 2 BP 106 EP 115 PG 10 WC Ecology SC Environmental Sciences & Ecology GA 415PH UT WOS:000167731300003 ER EF