FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Gingerich, O AF Gingerich, O TI The universe as theater for God's action SO THEOLOGY TODAY LA English DT Article 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 11 TC 0 Z9 0 U1 0 U2 0 PU SCIENCE PRESS PI EPHRATA PA 300 WEST CHESNUT ST, EPHRATA, PA 17522 USA SN 0040-5736 J9 THEOL TODAY JI Theol. Today PD OCT PY 1998 VL 55 IS 3 BP 305 EP 316 DI 10.1177/004057369805500302 PG 12 WC Religion SC Religion GA 126ZB UT WOS:000076324300002 ER PT J AU Laurance, WF AF Laurance, WF TI A crisis in the making: responses of Amazonian forests to land use and climate change SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Article ID BRAZILIAN AMAZON; EASTERN AMAZON; DEFORESTATION AB At least three global-change phenomena are having major impacts on Amazonian forests: (1) accelerating deforestation and logging; (2) rapidly changing patterns of forest loss; and (3) interactions between human land-use and climatic variability. Additional alterations caused by climatic change, rising concentrations of atmospheric carbon dioxide, mining, overhunting and other large-scale phenomena could also have important effects on the Amazon ecosystem. Consequently, decisions regarding Amazon forest use in the next decade are crucial to its future existence. C1 Natl Inst Res Amazon INPA, BR-69011970 Manaus, Amazonas, Brazil. Smithsonian Inst, Natl Museum Nat Hist, Biodivers Program, Washington, DC 20560 USA. RP Laurance, WF (reprint author), Natl Inst Res Amazon INPA, CP 478, BR-69011970 Manaus, Amazonas, Brazil. EM wfl@inpa.gov.br RI Laurance, William/B-2709-2012 NR 54 TC 121 Z9 129 U1 5 U2 32 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD OCT PY 1998 VL 13 IS 10 BP 411 EP 415 DI 10.1016/S0169-5347(98)01433-5 PG 5 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 121DR UT WOS:000075997500018 PM 21238369 ER PT J AU Harasewych, MG Adamkewicz, SL Plassmeyer, M Gillevet, PM AF Harasewych, MG Adamkewicz, SL Plassmeyer, M Gillevet, PM TI Phylogenetic relationships of the lower Caenogastropoda (Mollusca, Gastropoda, Architaenioglossa, Campaniloidea, Cerithioidea) as determined by partial 18S rDNA sequences SO ZOOLOGICA SCRIPTA LA English DT Article ID SYSTEMATICS AB Phylogenetic analyses of partial sequences spanning approximately 450 nucleotides near the 5' end of the 18S rDNA strongly support the monophyly of Apogastropoda and its constituent clades, Caenogastropoda and Heterobranchia. Representatives of the architaenioglossan groups Cyclophoroidea, Ampullariidae and Viviparidae invariably emerge within Caenogastropoda in all analyses. While the Cyclophoroidea and Ampullariidae are monophyletic, the varying position of Viviparidae in all outcomes contradicts its hypothesized sister group relationship with Ampullariidae, and thus the monophyly of Ampullarioidea. Because of the position of Viviparidae, Architaenioglossa does not emerge as a clade in any of our analyses. Campanile consistently emerges between Cyclophoroidea and Cerithioidea, or in a clade with Cyclophoroidea and Ampullariidae, a position not predicted by previous morphological studies. Maximum parsimony analyses of sequence data show Caenogastropoda to comprise a series of sequentially diverging higher taxa. However, maximum likelihood analyses as well as maximum parsimony analyses using only transversions divide Caenogastropoda into two clades, one containing the architaenioglossan taxa, Campaniloidea and Cerithioidea, the other containing the higher caenogastropod taxa included in Eucaenogastropoda (Haszprunar, 1988) [= Hypsogastropoda (Ponder & Lindberg 1997)]. Denser taxon sampling revealed insertions to be present in the 18S rDNA gene of several caenogastropod taxa. Earlier reports (Harasewych et nl. 1997b) of reduced sequence divergence levels in Caenogastropoda are shown to be restricted to Hypsogastropoda. Based on a broader taxonomic sampling, divergence levels within Caenogastropoda are comparable to those found within Heterobranchia. (C) 1998 The Norwegian Academy of Science and Letters. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. George Mason Univ, Dept Biol, Fairfax, VA 22030 USA. George Mason Univ, Inst Biosci Bioinformat & Biotechnol, Manassas, VA 20110 USA. RP Harasewych, MG (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 47 TC 30 Z9 30 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0300-3256 J9 ZOOL SCR JI Zool. Scr. PD OCT PY 1998 VL 27 IS 4 BP 361 EP 372 DI 10.1111/j.1463-6409.1998.tb00467.x PG 12 WC Evolutionary Biology; Zoology SC Evolutionary Biology; Zoology GA 137YP UT WOS:000076944900007 ER PT J AU Thiel, M AF Thiel, M TI Extended parental care in marine amphipods. I. Juvenile survival without parents SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE reproduction; extended parental care; amphipoda; soft-bottom; predation ID BONNELLII MILNE EDWARDS; LEMBOS-WEBSTERI BATE; LIFE-HISTORY; DYOPEDOS-MONACANTHUS; CAPRELLID AMPHIPODS; MATERNAL-CARE; TIDAL FLATS; CRUSTACEA; PREDATION; BEHAVIOR AB Extended parental care is found among a variety of marine peracarid species including endobenthic and epibenthic amphipods. After hatching from the female's brood pouch, small juveniles enjoy parental care for time periods of several days up to several weeks. This study examined whether small juvenile amphipods can survive without parental care to determine if this reproductive strategy is obligate or facultative. Juveniles of the burrow-dwelling species Leptocheirus pinguis (Stimpson 1853) and Casco bigelowi (Blake 1929) survived well in predator-free trays, indicating: that extended parental care in these species is a facultative reproductive strategy - juveniles can survive without their parents. Medium-sized juveniles of the epibenthic, suspension-feeding species Dyopedos monacanthus (Metzger 1875) survived relatively well in predator-free traps, but small juvenile D. monacanthus did not. This low survival rate of small D, monacanthus, even in predator-free trays, demonstrates that extended parental care is obligate for the survival of early juvenile stages in this epibenthic amphipod. When exposed to predators, juveniles of all three amphipod species were susceptible to predation, and reacted by emigration. Most juvenile L. pinguis and C. bigelowi emigrated or disappeared from sand shrimp Crangon septemspinosa treatments, but many remained in hermit crab Pagurus longicarpus treatments. Almost all juvenile D. monacanthus emigrated from both sand shrimp and hermit crab treatments, indicating that this epibenthic amphipod species is very susceptible to epibenthic predation. Survival of juvenile D. monacanthus was lower than that of L. pinguis and C. bigelowi both in predator-free and in predator trays. These results suggest that juveniles of this and other epibenthic peracarids depend on maternal care to a higher degree than juveniles of endobenthic burrow-dwelling species. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Maine, Darling Marine Ctr, Walpole, ME 04573 USA. RP Thiel, M (reprint author), Smithsonian Marine Stn, 5612 Old Dixie Highway, Ft Pierce, FL 34946 USA. EM thiel@sms.hboi.edu NR 64 TC 17 Z9 17 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 SEP 30 PY 1998 VL 227 IS 2 BP 187 EP 201 DI 10.1016/S0022-0981(97)00268-2 PG 15 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 120YB UT WOS:000075984400003 ER PT J AU Lukin, MD Hemmer, PR Loffler, M Scully, MO AF Lukin, MD Hemmer, PR Loffler, M Scully, MO TI Resonant enhancement of parametric processes via radiative interference and induced coherence SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; POPULATION-INVERSION; LASER; AMPLIFICATION; PULSE AB Nonlinear optical parametric processes are studied in a resonantly driven multilevel system displaying quantum interference effects. It is shown that in such systems a new regime of nonlinear amplification is possible, in which a pair of correlated Stokes and anti-Stokes fields can be generated from infinitesimally small initial values. An atomic coherence grating emerges during this process of efficient nonlinear amplification. The present analysis explains the results of recent optical phase conjugation experiments involving atomic phase coherence. [S0031-9007(98)01176-2]. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. USAF, Res Lab, Sensors Directorate, Bedford, MA 01731 USA. Univ Munich, Sekt Phys, D-85748 Garching, Germany. RP Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. NR 23 TC 147 Z9 150 U1 2 U2 10 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 SEP 28 PY 1998 VL 81 IS 13 BP 2675 EP 2678 DI 10.1103/PhysRevLett.81.2675 PG 4 WC Physics, Multidisciplinary SC Physics GA 123PJ UT WOS:000076133300014 ER PT J AU Orton, GS Fisher, BM Baines, KH Stewart, ST Friedson, AJ Ortiz, JL Marinova, M Ressler, M Dayal, A Hoffmann, W Hora, J Hinkley, S Krishnan, V Masanovic, M Tesic, J Tziolas, A Parija, KC AF Orton, GS Fisher, BM Baines, KH Stewart, ST Friedson, AJ Ortiz, JL Marinova, M Ressler, M Dayal, A Hoffmann, W Hora, J Hinkley, S Krishnan, V Masanovic, M Tesic, J Tziolas, A Parija, KC TI Characteristics of the Galileo probe entry site from Earth-based remote sensing observations SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INFRARED TELESCOPE FACILITY; LARGE PHASE ANGLES; JUPITER ATMOSPHERE; CLOUD STRUCTURE; UPPER TROPOSPHERE; EQUATORIAL BELT; JOVIAN PLANETS; ARRAY CAMERA; STRATOSPHERE; POLARIMETRY AB A reassessment of ground-based observations confirms to better than a 98% confidence level that the Galileo probe entered a 5-mu m hot spot, a region of unusual clarity and dryness, some 900 +/- 300 km north of its southern boundary. Cloud conditions at that point were similar to those in the center of this region, some 600 km further north. At the time of the probe entry, the region was evolving to a slightly larger size and even thinner cloud conditions, as evidenced by its rapidly brightening appearance at 4.78 mu m. The low reflectivity of the region in red light is highly anticorrelated with 4.78-mu m thermal emission, but this correlation breaks down in the blue. In general, the reflectivity of most hot spots is remarkably uniform, although the 4.78-mu m thermal emission is highly variable. A cloud structure most consistent with both the observed reflected sunlight and thermal emission properties consists of two layers: (1) a cloud layer above the 450-mbar level extending up to the 150-mbar level that probably consists of submicron sized particles and (2) a tropospheric cloud that is probably below the 1-bar level, possibly ammonia hydrosulfide, with low optical thickness in the infrared. A population of particles larger than similar to 3 mu m, clearly present at the NH3 ice cloud level outside hot spots, is absent inside them. The NH3 gas abundance near 300-400 mbar pressure does not appear to be unusually depleted in hot spots. Zonal structures in the tropospheric temperature field near the probe entry site were not correlated with the location of 5-mu m hot spots but moved at speeds closer to the internal rotation rate of the planet. The propel ties of the tropospheric thermal waves at the probe entry latitude show little correlation to the properties of the 5-mu m hot spot waves. Temperatures at the probe entry site derived from remote sensing are warmer than the Atmospheric Structure Instrument (ASI) experiment results near the tropopause, probably because the low-temperature ASI features are confined to regions smaller than the similar to 6000-km resolution characteristic of the remote sensing. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91125 USA. Reed Coll, Dept Phys, Portland, OR 97202 USA. Univ Arizona, Stewart Observ, Tucson, AZ 85721 USA. Univ Cambridge, Trinity Coll, Cambridge CB3 9EW, England. CALTECH, Dept Comp Sci, Pasadena, CA 91125 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Belgrade, Sch Elect Engn, YU-11000 Belgrade, Yugoslavia. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Exel Internet Serv, Madras 600014, Tamil Nadu, India. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. RP Orton, GS (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91125 USA. OI Hora, Joseph/0000-0002-5599-4650 NR 47 TC 53 Z9 53 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD SEP 25 PY 1998 VL 103 IS E10 BP 22791 EP 22814 DI 10.1029/98JE02380 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 168VC UT WOS:000078713000008 ER PT J AU Mueller, UG Rehner, SA Schultz, TR AF Mueller, UG Rehner, SA Schultz, TR TI The evolution of agriculture in ants SO SCIENCE LA English DT Article ID FUNGUS-GROWING ANTS AB Cultivation of fungi for food by fungus-growing ants (Attini: Formicidae) originated about 50 million years ago, The subsequent evolutionary history of this agricultural symbiosis was inferred from phylogenetic and population-genetic patterns of 553 cultivars isolated from gardens of "primitive" fungus-growing ants. These patterns indicate that fungus-growing ants succeeded at domesticating multiple cultivars, that the ants are capable of switching to novel cultivars, that single ant species farm a diversity of cultivars, and that cultivars are shared occasionally between distantly related ant species, probably by lateral transfer between ant colonies. C1 Univ Maryland, Dept Biol, College Pk, MD 20742 USA. Smithsonian Trop Res Inst, Balboa, Panama. Univ Puerto Rico, Dept Biol, Rio Piedras, PR 00931 USA. Smithsonian Inst, Natl Museum Nat Hist, Washington, DC 20560 USA. RP Mueller, UG (reprint author), Univ Maryland, Dept Biol, College Pk, MD 20742 USA. NR 15 TC 227 Z9 235 U1 8 U2 67 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 SEP 25 PY 1998 VL 281 IS 5385 BP 2034 EP 2038 DI 10.1126/science.281.5385.2034 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 124BV UT WOS:000076161800058 ER PT J AU Rodriguez, LF D'Alessio, P Wilner, DJ Ho, PTP Torrelles, JM Curiel, S Gomez, Y Lizano, S Pedlar, A Canto, J Raga, AC AF Rodriguez, LF D'Alessio, P Wilner, DJ Ho, PTP Torrelles, JM Curiel, S Gomez, Y Lizano, S Pedlar, A Canto, J Raga, AC TI Compact protoplanetary disks around the stars of a young binary system SO NATURE LA English DT Article ID MAIN-SEQUENCE STARS; L1551 IRS-5; MOLECULAR OUTFLOWS; FORMING REGIONS; HL TAURI; ACCRETION; MULTIPLICITY; SEARCH AB Planet formation is believed to occur in the disks of gas and dust that surround young salar-type stars(1). Most stars, however, form in multiple systems(2-5), where the presence of a close companion could affect the structure of the disk(6-8) and perhaps interfere with planet formation. It has been difficult to investigate this because of the resolution needed Here we report interferometric observations (at a wavelength of 7 mm) of the core of the star-forming region L1551. We have achieved a linear resolution of seven astronomical units (less than the diameter of Jupiter's orbit). The core of L1551 contains two distinct disks, with a separation of 45 AU; these appear to be associated with a binary system. Both disks are spatially resolved, with semi-major axes of about 10 AU, which is about a factor of ten smaller than disks around isolated stars(9-12). The disk masses are of order 0.05 solar masses, which could be enough to form planetary systems like our own. C1 Natl Autonomous Univ Mexico, Inst Astron, Mexico City 04510, DF, Mexico. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. UIB, CSIC, IMEDEA, Palma de Mallorca 07071, Spain. Univ Manchester, Nuffield Radio Astron Labs, Macclesfield SK11 9DL, Cheshire, England. RP Rodriguez, LF (reprint author), Natl Autonomous Univ Mexico, Inst Astron, Apartado Postal 70264, Mexico City 04510, DF, Mexico. OI Torrelles, Jose Maria/0000-0002-6896-6085 NR 30 TC 148 Z9 148 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD SEP 24 PY 1998 VL 395 IS 6700 BP 355 EP 357 DI 10.1038/26421 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 122QW UT WOS:000076083800044 ER PT J AU Pastorino, G Penchaszadeh, P AF Pastorino, G Penchaszadeh, P TI Epitonium fabrizioi (Gastropoda : Epitoniidae), a new species from Patagonia, Argentina SO NAUTILUS LA English DT Article AB Epitonium fabrizioi, a new species of gastropod mollusk belonging to the family Epitoniidae, is described from shallow waters of Puerto Piramides, Chubut Province, Argentina. This new species is similar to E. georgettinum from the same area, which was known only from its shell. It can be distinguished from E. georgettinum by its smaller size, more straight profile and, by its sharper, most numerous ribs. In addition, the protoconch of the new species consists of 4.25 whorls. Its radula has only marginal teeth, each with three cusps. The outermost cusp is larger and hook-like, the central and inner cusps are shorter and similar in size. An additional, obsolete, cusp is present near the base of the teeth. The egg capsules have a mean diameter of 76 mu m. The new species is compared with E. georgettinum, the species with which it co-occurs, and E, albidum. C1 Museo La Plata, Dept Paleozool Invertebrados, RA-1900 La Plata, Argentina. RP Pastorino, G (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Div Mollusks, Washington, DC 20560 USA. NR 20 TC 4 Z9 4 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 SEP 22 PY 1998 VL 112 IS 2 BP 63 EP 68 PG 6 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 126QL UT WOS:000076304600004 ER PT J AU Pelt, J Hjorth, J Refsdal, S Schild, R Stabell, R AF Pelt, J Hjorth, J Refsdal, S Schild, R Stabell, R TI Estimation of multiple time delays in complex gravitational lens systems SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE methods : statistical; quasars : individual : PG 1115+080; gravitational lensing ID QSO-0957+561 AB We generalize the nonparametric dispersion minimization method of time delay estimation for the case when more than two quasar images are available. This allows us to analyse time delays in complex gravitational lens systems in a model independent manner. We apply the new method to the recent observations of the quadruply imaged quasar PG 1115+080 and show that our nonparametric estimates roughly coincide with the values obtained with optimal filtering and smoothing techniques. Because our method uses a minimal set of assumptions and is computationally simpler it may be a method of choice, especially for the early stages of an investigation when the available data for a new lens system are scarce. C1 Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Ctr Adv Study, N-0271 Oslo, Norway. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Hamburger Sternwarte, D-21029 Hamburg, Germany. NORDITA, DK-2100 Copenhagen, Denmark. Tartu Observ, EE-2444 Toravere, Estonia. RP Stabell, R (reprint author), Univ Oslo, Inst Theoret Astrophys, POB 1029, N-0315 Oslo, Norway. RI Pelt, Jaan/G-4916-2010; Hjorth, Jens/M-5787-2014 OI Hjorth, Jens/0000-0002-4571-2306 NR 9 TC 14 Z9 14 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 SEP 20 PY 1998 VL 337 IS 3 BP 681 EP 684 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 123KJ UT WOS:000076124100005 ER PT J AU Bromley, BC Press, WH Lin, H Kirshner, RP AF Bromley, BC Press, WH Lin, H Kirshner, RP TI Spectral classification and luminosity function of galaxies in the Las Campanas Redshift Survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : fundamental parameters; galaxies : luminosity function, mass function; large-scale structure of universe; surveys ID EMISSION-LINE SPECTRA; NEARBY GALAXIES; DENSITY; FIELD; PARAMETERS; MORPHOLOGY; EVOLUTION; SEQUENCE; SAMPLE AB We construct a spectral classification scheme for the galaxies of the Las Campanas Redshift Survey (LCRS) based on a principal-component analysis of the measured galaxy spectra. We interpret the physical significance of our six spectral types and conclude that they are sensitive to morphological type and to the amount of active star formation. In this first analysis of the LCRS to include spectral classification, we estimate the general luminosity function, expressed as a weighted sum of the type-specific luminosity functions. In the R-band magnitude range of -23 < M less than or equal to -16.5 this function exhibits a broad shoulder centered on M approximate to -20 and an increasing faint-end slope that formally converges on alpha approximate to -1.8 in the faint limit. The Schechter parameterization does not provide a good representation in this case, a fact that may partly explain the reported discrepancy between the luminosity functions of the LCRS and other redshift catalogs such as the Century Survey. The discrepancy may also arise from environmental effects such as the density-morphology relationship for which we see strong evidence in the LCRS galaxies. However, the Schechter parameterization is more effective for the luminosity functions of the individual spectral types. The data show a significant, progressive steepening of the faint-end slope, from alpha approximate to +0.5 for early-type objects to alpha approximate to -1.8 for the extreme late-type galaxies. The extreme late-type population has a sufficiently high space density that its contribution to the general luminosity function is expected to dominate at magnitudes fainter than M = -16. We conclude that an evaluation of type dependence is essential to any assessment of the general luminosity function. C1 Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Toronto, Dept Astron, Toronto, ON, Canada. RP Bromley, BC (reprint author), Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. NR 33 TC 109 Z9 109 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 1998 VL 505 IS 1 BP 25 EP 36 DI 10.1086/306144 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152LA UT WOS:000077777900005 ER PT J AU Turner, A Ferrarese, L Saha, A Bresolin, F Kennicutt, RC Stetson, PB Mould, JR Freedman, WL Gibson, BK Graham, JA Ford, H Han, MS Harding, P Hoessel, JG Huchra, JP Hughes, SMG Illingworth, GD Kelson, DD Macri, L Madore, BF Phelps, R Rawson, D Sakai, S Silbermann, NA AF Turner, A Ferrarese, L Saha, A Bresolin, F Kennicutt, RC Stetson, PB Mould, JR Freedman, WL Gibson, BK Graham, JA Ford, H Han, MS Harding, P Hoessel, JG Huchra, JP Hughes, SMG Illingworth, GD Kelson, DD Macri, L Madore, BF Phelps, R Rawson, D Sakai, S Silbermann, NA TI The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. XI. The Cepheids in NGC 4414 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; galaxies : distances and redshifts; galaxies : individual (NGC 4414) ID IA SUPERNOVAE; PEAK BRIGHTNESS; STELLAR PHOTOMETRY; NEARBY GALAXIES; SPIRAL GALAXIES; VELOCITY-FIELD; LIGHT CURVES; CALIBRATION; DISCOVERY; CONSTANT AB We report the discovery of Cepheid variable stars in the galaxy NGC 4414, as part of the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale. Observations were obtained with the HST Wide-Field and Planetary Camera 2 (WFPC2) for 13 epochs at V (F555W) and 4 at I (F814W). Photometry was performed using two independent programs, DoPHOT and DAOPHOT/ALLFRAME. We find 11 Cepheids with high-quality light curves and well-determined periods of 19-70 days. Nine of these Cepheids are used in fitting the period-luminosity relation. Assuming an LMC distance modulus of 18.50 mag and E(B-V) = 0.10 mag, we derive a reddening-corrected distance modulus for NGC 4414 of 31.41 +/- 0.17 (random) +/- 0.16 (systematic) mag, corresponding to a distance of 19.1 +/- 1.5 (random) +/- 1.4 (systematic) Mpc. We derive a mean color excess for NGC 4414 of E(V-I) = 0.02 +/- 0.05 mag. NGC 4414 is a calibrator of the Tully-Fisher and Type Ia supernova secondary distance indicators, and we briefly discuss the implications of the new distance for these methods. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, Pasadena, CA 91125 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Inst Adv Studies, Weston, ACT 2611, Australia. Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Wisconsin, Madison, WI 53706 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Royal Greenwich Observ, Cambridge CB3 0EZ, England. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Turner, A (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 57 TC 47 Z9 47 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 1998 VL 505 IS 1 BP 207 EP 229 DI 10.1086/306150 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152LA UT WOS:000077777900017 ER PT J AU Forrey, RC Woo, JW Cho, KJ AF Forrey, RC Woo, JW Cho, KJ TI Model for astrophysical X-ray absorption fine structure SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; galaxies : ISM; techniques : spectroscopic; X-rays : galaxies ID MULTIPLE-SCATTERING CALCULATIONS; INTERSTELLAR GRAINS; STRUCTURE EXAFS; SPECTRA AB We present a theoretical model and database designed to provide analysis of astrophysical X-ray absorption fine structure (XAFS). The model includes spherical wave corrections and multiple-scattering contributions to the modification of the X-ray absorption coefficient. The model and database provide the basis for the astrophysical XAFS analysis (AXA) tool, which may be used to analyze properties of interstellar grains and molecules from high-resolution X-ray spectra expected to be observed by future satellite missions (e.g., the Advanced X-ray Astrophysics Facility). C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Stanford Univ, Dept Mech Engn, Mech & Computat Div, Stanford, CA 94305 USA. RP Forrey, RC (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 22 TC 9 Z9 9 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 1998 VL 505 IS 1 BP 236 EP 243 DI 10.1086/306133 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152LA UT WOS:000077777900019 ER PT J AU Seta, M Hasegawa, T Dame, TM Sakamoto, S Oka, T Handa, T Hayashi, M Morino, JI Sorai, K Usuda, KS AF Seta, M Hasegawa, T Dame, TM Sakamoto, S Oka, T Handa, T Hayashi, M Morino, JI Sorai, K Usuda, KS TI Enhanced Co J=2-1/J=1-0 ratio as a marker of supernova remnant-molecular cloud interactions: The cases of W44 and IC 443 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : individual (W44, IC 443); ISM : molecules; radio lines : ISM; supernova remnants ID 1ST GALACTIC QUADRANT; MILKY-WAY; H-I; INFRARED-SPECTROSCOPY; INTERSTELLAR-MEDIUM; SHOCK CHEMISTRY; NOVA REMNANT; ABSORPTION-MEASUREMENTS; J=2-1 SURVEY; IC-443 AB We present results of CO J = 2-1 line mapping of molecular clouds in the vicinity of the supernova remnants (SNRs) W44 and IC 443. Large areas spanning similar to 1.degrees 5 x 2 degrees were observed with the 9' beam of the University of Tokyo-Nobeyama Radio Observatory 60 cm Survey Telescope. We identified six giant molecular clouds (GMCs) with masses (0.3-3) x 10(5) M. around W44. Three show evidence of interaction with the SNR. In particular, one exhibits a line wing emission and an abrupt velocity shift at the position at which the cloud overlaps with the SNR. The CO J = 2-1/J = 1-0 line intensity ratio significantly exceeds unity (1.3) in the wing. In IC 443, a high-velocity line wing emission was detected in CO J = 2-1 with our 9' beam. The CO J = 2-1/J = 1-0 ratio is extremely high (>3) in the wing, which suggests that the emission comes from spatially extended optically thin (tau - 0.1), dense [n(H-2) similar to 10(5) cm(-3)], and warm (similar to 80 K) gas. W44 is established as a good example of an SNR interacting with GMCs, while IC 443 is in interaction with a low-mass dark cloud. The mass and kinetic energy of the shocked gas are, respectively, 1 x 10(3) M. and 4 x 10(48) ergs in W44, and 70 M. and 6 x 10(47) ergs in IC 443. A very high CO J = 2-1/J = 1-0 ratio in the line wings of a GMC may be a useful marker of interaction with an SNR. Such a marker would be extremely valuable for determining GMC-SNR associations in the inner Galaxy where numerous GMCs often lie along the line of sight. Such associations often provide the best means of determining SNR distances. C1 Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Astron Inst, Tokyo 1818588, Japan. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Astron Observ, Tokyo 1818588, Japan. RP Seta, M (reprint author), Commun Res Lab, Nukuikitamachi, Tokyo 1848795, Japan. RI Sorai, Kazuo/G-3347-2012 NR 72 TC 81 Z9 83 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 1998 VL 505 IS 1 BP 286 EP 298 DI 10.1086/306141 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152LA UT WOS:000077777900025 ER PT J AU Schou, J Antia, HM Basu, S Bogart, RS Bush, RI Chitre, SM Christensen-Dalsgaard, J Di Mauro, MP Dziembowski, WA Eff-Darwich, A Gough, DO Haber, DA Hoeksema, JT Howe, R Korzennik, SG Kosovichev, AG Larsen, RM Pijpers, FP Scherrer, PH Sekii, T Tarbell, TD Title, AH Thompson, MJ Toomre, J AF Schou, J Antia, HM Basu, S Bogart, RS Bush, RI Chitre, SM Christensen-Dalsgaard, J Di Mauro, MP Dziembowski, WA Eff-Darwich, A Gough, DO Haber, DA Hoeksema, JT Howe, R Korzennik, SG Kosovichev, AG Larsen, RM Pijpers, FP Scherrer, PH Sekii, T Tarbell, TD Title, AH Thompson, MJ Toomre, J TI Helioseismic studies of differential rotation in the solar envelope by the solar oscillations investigation using the Michelson Doppler Imager SO ASTROPHYSICAL JOURNAL LA English DT Review DE convection; Sun : interior; Sun : oscillations; Sun : rotation ID ANGULAR-MOMENTUM TRANSPORT; MODE FREQUENCY SPLITTINGS; STELLAR RADIATIVE ZONES; CONVECTION ZONE; INTERNAL-ROTATION; MAGNETIC-FIELDS; SPHERICAL-SHELL; COMPRESSIBLE CONVECTION; NUMERICAL SIMULATIONS; OUTER PLANETS AB The splitting of the frequencies of the global resonant acoustic modes of the Sun by large-scale flows and rotation permits study of the variation of angular velocity Omega with both radius and latitude within the turbulent convection zone and the deeper radiative interior. The nearly uninterrupted Doppler imaging observations, provided by the Solar Oscillations Investigation (SOI) using the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO) spacecraft positioned at the L-1 Lagrangian point in continuous sunlight, yield oscillation power spectra with very high signal-to-noise ratios that allow frequency splittings to be determined with exceptional accuracy. This paper reports on joint helioseismic analyses of solar rotation in the convection zone and in the outer part of the radiative core. Inversions have been obtained for a medium-l mode set (involving modes of angular degree l extending to about 250) obtained from the first 144 day interval of SOI-MDI observations in 1996. Drawing inferences about the solar internal rotation from the splitting data is a subtle process. By applying more than one inversion technique to the data, we get some indication of what are the more robust and less robust features of our inversion solutions. Here we have used seven different inversion methods. To test the reliability and sensitivity of these methods, we have performed a set of controlled experiments utilizing artificial data. This gives us some confidence in the inferences we can draw from the real solar data. The inversions of SOI-MDI data have confirmed that the decrease of Omega with latitude seen at the surface extends with little radial variation through much of the convection zone, at the base of which is an adjustment layer, called the tachocline, leading to nearly uniform rotation deeper in the radiative interior. A prominent rotational shearing layer in which Omega increases just below the surface is discernible at low to mid latitudes. Using the new data, we have also been able to study the solar rotation closer to the poles than has been achieved in previous investigations. The data have revealed that the angular velocity is distinctly lower at high latitudes than the values previously extrapolated from measurements at lower latitudes based on surface Doppler observations and helioseismology. Furthermore, we have found some evidence near latitudes of 75 degrees of a submerged polar jet which is rotating more rapidly than its immediate surroundings. Superposed on the relatively smooth latitudinal variation in Omega are alternating zonal bands of slightly faster and slower rotation, each extending some 10 degrees to 15 degrees in latitude. These relatively weak banded flows have been followed by inversion to a depth of about 5% of the solar radius and appear to coincide with the evolving pattern of "torsional oscillations" reported from earlier surface Doppler studies. C1 Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. Tata Inst Fundamental Res, Mumbai 400005, India. Aarhus Univ, Inst Fys & Astron, DK-8000 Aarhus C, Denmark. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Queen Mary Univ London, Astron Unit, London E1 4NS, England. Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. Aarhus Univ, Datalogisk Inst, DK-8000 Aarhus C, Denmark. Univ Catania, UdR Catania Ist Astron, CNR, Grp Nazl Astron, I-95125 Catania, Italy. Copernicus Astron Ctr, PL-03610 Warsaw, Poland. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. RP Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. RI Pijpers, Frank/A-1734-2009; Basu, Sarbani/B-8015-2014; OI Basu, Sarbani/0000-0002-6163-3472; Di Mauro, Maria Pia/0000-0001-7801-7484 NR 119 TC 605 Z9 612 U1 1 U2 14 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 SEP 20 PY 1998 VL 505 IS 1 BP 390 EP 417 DI 10.1086/306146 PN 1 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152LA UT WOS:000077777900035 ER PT J AU Wood, BE Karovska, M Cook, JW Brueckner, GE Howard, RA Korendyke, CM Socker, DG AF Wood, BE Karovska, M Cook, JW Brueckner, GE Howard, RA Korendyke, CM Socker, DG TI Search for brightness variations in Fe xiv Coronagraph observations of the quiescent solar corona SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona ID X-RAY TELESCOPE; TRANSIENT BRIGHTENINGS; LOOP INTERACTION; HIGH-RESOLUTION; ACTIVE REGIONS; FLARES; YOHKOH; RECONNECTION; OSCILLATIONS; MORPHOLOGY AB We use Fe XIV 5303 Angstrom green line images obtained by the Large Angle Spectrometric Coronagraph (LASCO) on board SOHO to search for variability in the quiescent solar corona in the shortest observable timescales. The observing program obtained Fe XIV images of a small area of the inner corona every 2 minutes over a period of 1 hr. We present results from two executions of this program taken several months apart. The most obvious variability observed in the two sequences is in the form of quasi-steady brightening on timescales of at least an hour. Of particular interest are two compact loops that are observed to vary significantly during the course of the observations. Superposed on the long-term brightening in these loops are statistically significant variations on timescales of about 30 minutes. In both loops, the overall brightening is greatest at the apparent loop tops, where the intensity increases by at least 25%. In one loop there appears to be a flow up one of the legs of the loop. We place these observations in context with earlier observations of coronal variability, and we discuss the energy requirements for the observed brightening. Emission measures computed from Fe XIV intensities measured within the two brightening loops are over an order of magnitude lower than those typically found for active regions on the solar disk, which suggests significantly lower average densities. For one of the loops, we measure densities in the range n(e) = (5.0-7.4) x 10(8) cm(-3). Lower than average densities are expected for the two loops, given that they reach more than 1 pressure scale height above the solar limb. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 46 TC 8 Z9 8 U1 0 U2 0 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 SEP 20 PY 1998 VL 505 IS 1 BP 432 EP 442 DI 10.1086/306159 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152LA UT WOS:000077777900037 ER PT J AU Reed, K Manning, RB AF Reed, K Manning, RB TI Horton H. Hobbs, Jr. (29 March 1914 22 March 1994). Biographical notes SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Biographical-Item AB The 211 papers and abstracts published by the late Horton H. Hobbs, Jr, are cited and annotated by a list of new taxa published in each paper. An alphabetical list of taxa named by Hobbs is provided; the repository and the catalogue number are cited for each holotype. Hobbs's reminiscences of his introduction to crayfishes and his early work are summarized from an oral interview. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Reed, K (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 0 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 SEP 18 PY 1998 VL 111 IS 3 BP 473 EP 503 PG 31 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 123EN UT WOS:000076113000001 ER PT J AU Lucas, SG Emry, RJ Tleuberdina, PA AF Lucas, SG Emry, RJ Tleuberdina, PA TI Franconictis (Mammalia : Carnivora) from the late Oligocene of eastern Kazakstan SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB The right dentary of a small carnivore from near Ayaguz in eastern Kazakstan is identified as Franconictis sp. aff. F. vireti (Dehm). Francoitictis has previously been reported only from the early Miocene of Europe. Previous reports of Plesictis from Asia are not well founded. Franconictis from Ayaguz extends the geographic range of the genus into Asia and its temporal range back to the late Oligocene. C1 New Mexico Museum Nat Hist & Sci, Albuquerque, NM 87104 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. Natl Acad Sci, Inst Zool, Alma Ata 480032, Kazakhstan. RP Lucas, SG (reprint author), New Mexico Museum Nat Hist & Sci, 1801 Mt Rd NW, Albuquerque, NM 87104 USA. NR 27 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 SEP 18 PY 1998 VL 111 IS 3 BP 504 EP 510 PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 123EN UT WOS:000076113000002 ER PT J AU Graves, GR AF Graves, GR TI Diagnoses of hybrid hummingbirds (Aves : Trochilidae). 6. An intergeneric hybrid, Aglaiocercus kingi x Metallura tyrianthina, from Venezuela SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID HYBRIDIZATION; SYSTEMATICS; HELIANGELUS; EVOLUTION AB An intergeneric hybrid hummingbird, Aglaiocercus kingi x Metallura tyrianthina, is described. External measurements of the hybrid are intermediate of those of the parental species. Back plumage iridescence is bluer (511 nm) in the hybrid than in either of the parental species (553-571 nm). This color shift is thought to be caused by a developmental aberrancy or mutation which affects melanin granules that produce iridescence in feather keratins. 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. NR 35 TC 15 Z9 16 U1 0 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 SEP 18 PY 1998 VL 111 IS 3 BP 511 EP 520 PG 10 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 123EN UT WOS:000076113000003 ER PT J AU Ahyong, ST Manning, RB AF Ahyong, ST Manning, RB TI Two new species of Erugosquilla from the Indo-West Pacific (Crustacea : Stomatopoda : Squillidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB The fifth and sixth species of Erugosquilla to be recognized are E. grahami, new species, from Australia and Taiwan; and E. serenei, new species, from Vietnam. Both species resemble E. woodmasoni (Kemp) in lacking distinct tubercles adjacent to the median carina of the telson, and in this feature differ from E. massavensis (Kossmann) and E. hesperia (Manning), both from the western Indian Ocean. The two new species differ from E. woodmasoni in having the anterior margin of the ophthalmic somite trapezoidal rather than rounded in shape; and the outer inferodistal angle of the raptorial merus produced into a blunt angle rather than a spine. Erugosquilla grahami and E. serenei can be distinguished by the length of the prelateral lobe of the telson and the color in life of the antennal peduncle. C1 Australian Museum, Dept Marine Invertebrates, Sydney, NSW 2000, Australia. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Ahyong, ST (reprint author), Australian Museum, Dept Marine Invertebrates, 6 Coll St, Sydney, NSW 2000, Australia. NR 12 TC 3 Z9 5 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 SEP 18 PY 1998 VL 111 IS 3 BP 653 EP 662 PG 10 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 123EN UT WOS:000076113000014 ER PT J AU Reid, M AF Reid, M TI Perspectives: Astrophysics - Shedding light on black holes SO SCIENCE LA English DT Editorial Material C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Reid, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 6 TC 1 Z9 1 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 SEP 18 PY 1998 VL 281 IS 5384 BP 1815 EP 1816 DI 10.1126/science.281.5384.1815 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 121HK UT WOS:000076007100037 ER PT J AU Hinz, PM Angel, JRP Hoffmann, WF McCarthy, DW McGuire, PC Cheselka, M Hora, JL Woolf, NJ AF Hinz, PM Angel, JRP Hoffmann, WF McCarthy, DW McGuire, PC Cheselka, M Hora, JL Woolf, NJ TI Imaging circumstellar environments with a nulling interferometer SO NATURE LA English DT Article ID PLANETS AB Extrasolar planets must be imaged directly if their nature is to be better understood. But this will be difficult, as the bright light from the parent star (or rather its diffracted halo in the imaging apparatus) can easily overwhelm nearby faint sources. Bracewell has proposed(1) a way of selectively removing: starlight before detection, by superposing the light from two telescopes so that the stellar wavefronts interfere destructively. Such a 'nulling' interferometer could be used in space to search for extrasolar Earth-like planets through their thermal emission and to determine through spectroscopic analysis if they possess the atmospheric signatures of life(2-4). Here we report mid-infrared observations using two co-mounted telescopes of the Multiple Mirror Telescope that demonstrate the viability of this technique. Images of unresolved stars are seen to disappear almost completely, while Light from a nearby source as dose as 0.2 arcsec remains, as shown by images of Betelgeuse. With this star cancelled, there remains the thermal image of its surrounding, small dust nebula. In the future, larger ground-based interferometers that correct for atmospheric distortions (using adaptive optics) should achieve better cancellation, allowing direct detection of warm, Jupiter-size planets and faint zodiacal dust around other nearby stars(5). C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Hinz, PM (reprint author), Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA. EM phinz@as.arizona.edu RI McGuire, Patrick/D-2962-2013; OI McGuire, Patrick/0000-0001-6592-4966; Hora, Joseph/0000-0002-5599-4650 NR 17 TC 71 Z9 71 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD SEP 17 PY 1998 VL 395 IS 6699 BP 251 EP 253 DI 10.1038/26172 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 120TZ UT WOS:000075974600042 ER PT J AU Riley, SM AF Riley, SM TI Model behavior. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC 20560 USA. RP Riley, SM (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 SEP 15 PY 1998 VL 123 IS 15 BP 112 EP 113 PG 2 WC Information Science & Library Science SC Information Science & Library Science GA 116YY UT WOS:000075754000294 ER PT J AU Plag, HP Ambrosius, B Baker, TF Beutler, G Bianco, G Blewitt, G Boucher, C Davis, JL Degnan, JJ Johansson, JM Kahle, HG Kumkova, I Marson, I Mueller, S Pavlis, EC Pearlman, MR Richter, B Spakman, W Tatevian, SK Tomasi, P Wilson, P Zerbini, S AF Plag, HP Ambrosius, B Baker, TF Beutler, G Bianco, G Blewitt, G Boucher, C Davis, JL Degnan, JJ Johansson, JM Kahle, HG Kumkova, I Marson, I Mueller, S Pavlis, EC Pearlman, MR Richter, B Spakman, W Tatevian, SK Tomasi, P Wilson, P Zerbini, S TI Scientific objectives of current and future WEGENER activities SO TECTONOPHYSICS LA English DT Review DE Space Geodesy; gravity; sea level; post-glacial rebound; African-Eurasian plate boundary; 3-D deformation of the Earth ID MEAN-SEA-LEVEL; GLACIAL ISOSTATIC-ADJUSTMENT; COMPUTING 3-DIMENSIONAL DEFORMATIONS; LINE INTERFEROMETRY MEASUREMENTS; VISCOELASTIC RELAXATION SPECTRA; SCALE CLIMATE VARIABILITY; GLOBAL POSITIONING SYSTEM; HORIZONTAL CRUSTAL MOTION; CURRENT PLATE MOTIONS; ATMOSPHERIC-PRESSURE AB The WEGENER group has promoted the development of scientific space-geodetic activities in the Mediterranean and in the European area for the last fifteen years and has contributed to the establishment of geodetic networks designed particularly for earth science research. WEGENER currently has three scientific objectives which are related to plate-boundary processes, sea-level and height changes, and postglacial rebound. Tn a full exploitation of the space-geodetic techniques, namely SLR, VLBI and GPS, the individual scientific projects do not only pursue these objectives but also contribute to improving and developing the observation techniques as well as the modelling theories. Tn the past, particularly SLR observations within WEGENER-MEDLAS have provided a fundamental contribution to determine the regional kinematics of the tectonic plates in the Mediterranean with high precision. With GPS, spatially denser site distributions are feasible, and in several WEGENER projects detailed studies of tectonically active areas were possible on the basis of repeated episodic GPS observations. Current projects associated with WEGENER are successful in separating crustal movements and absolute sea-level variations as well as in monitoring postglacial rebound. These tasks require high-precision height determinations, a problem central to all of the present WEGENER activities. In these projects, continuously occupied GPS sites are of increasing importance. Time series of heights observed with continuous GPS can be determined with a few centimeters RMS error thus enabling the reliable estimates of vertical rates over relatively shea time intervals. Regional networks of continuous GPS sites are already providing results relevant, for example, for the study of postglacial rebound. The Mediterranean area is an extraordinary natural laboratory for the study of seismotectonic processes, and the wealth of observations acquired in previous WEGENER projects together with new space-geodetic observations will allow the test of geophysical hypotheses linking three-dimensional deformations of the Earth's surface to the dynamics of the Earth's interior. In particular, it is anticipated that WEGENER projects will aim at a test of the slab-detachment hypothesis. The complex investigations on sea-level fluctuations presently carried out at basin scale from the Strait of Gibraltar to the Black Sea make it possible to study the present and recent past interactions of ocean, atmosphere and solid Earth, as well as to develop appropriate models to assess future aspects. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Norwegian Mapping Author, Honefoss, Norway. Delft Univ Technol, Fac Aerosp Engn, Delft, Netherlands. Proudman Oceanog Lab, Bidston, Merseyside, England. Astron Inst Berne, Bern, Switzerland. Agenzia Spaziale Italiana, Matera, Italy. Univ Newcastle Upon Tyne, Dept Surveying, Newcastle Upon Tyne, Tyne & Wear, England. Inst Geog Natl, St Mande, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. Chalmers Univ Technol, Onsala Space Observ, S-43900 Onsala, Sweden. ETH Honggerberg, Inst Geodasie & Photogrammetrie, Zurich, Switzerland. Russian Acad Sci, Inst Appl Astron, St Petersburg, Russia. Univ Trieste, DINMA, Trieste, Italy. Smithsonian Astrophys Observ, Cambridge, MA USA. Inst Angew Geodasie, Frankfurt, Germany. Univ Utrecht, Fac Earth Sci, Geodynam Res Inst, Utrecht, Netherlands. Russian Acad Sci, Astron Council, Space Geodesy Dept, Moscow, Russia. CNR, Ist Radioastron, Area Ric, Bologna, Italy. Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany. Univ Bologna, Dept Phys, I-40126 Bologna, Italy. RP Plag, HP (reprint author), Norwegian Mapping Author, Honefoss, Norway. RI Boucher, Claude/A-2843-2011; Davis, James/D-8766-2013; OI Davis, James/0000-0003-3057-477X; Bianco, Giuseppe/0000-0002-4538-6467 NR 166 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD SEP 15 PY 1998 VL 294 IS 3-4 BP 177 EP 223 DI 10.1016/S0040-1951(98)00100-0 PG 47 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 138GV UT WOS:000076964400003 ER PT J AU Scherneck, HG Johansson, JM Mitrovica, JX Davis, JL AF Scherneck, HG Johansson, JM Mitrovica, JX Davis, JL TI The BIFROST project: GPS determined 3-D displacement rates in Fennoscandia from 800 days of continuous observations in the SWEPOS network SO TECTONOPHYSICS LA English DT Article DE postglacial isostatic adjustment; satellite geodesy; global positioning system; regional networks ID GLACIAL ISOSTATIC-ADJUSTMENT; SIGNAL SCATTERING; MANTLE VISCOSITY; SITE POSITIONS; RELAXATION; MODELS; LOAD AB This presentation summarizes results obtained from 800 days of operation of SWEPOS, the Swedish permanent GPS array. Located in the area of the Fennoscandian land uplift, SWEPOS is the main measuring device for the BIFROST project, aiming primarily at determination of crustal motions and changes in global sea level in conjunction with postglacial rebound. As a future prospect the project will contribute to determine present-day changes in the oceanic water budget as well as strive for a more complete understanding of the viscoelastic structure of crust and mantle. We show solutions of site positions obtained from the daily processing of the GPS observations. We determine their variations in time, discerning them from plate or frame orientation, and discuss a number of perturbation effects. Among these the possibility of random walk monument motion is considered. The feasibility of single-site solutions rather than baseline pairs is demonstrated. On the basis of 800 days of operation of the permanent network, data analysis is able to confirm the general rebound pattern. Comparison with both modelling results and evidence from mareograph and precise levelling shows high rates of vertical surface displacement from GPS measurements in the centre of the Pleistocene glaciation region. We discuss the possibility of rate biases due to problems with the terrestrial reference frames. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Chalmers Univ Technol, Onsala Space Observ, S-43992 Onsala, Sweden. Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Scherneck, HG (reprint author), Chalmers Univ Technol, Onsala Space Observ, S-43992 Onsala, Sweden. RI Davis, James/D-8766-2013 OI Davis, James/0000-0003-3057-477X NR 27 TC 23 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD SEP 15 PY 1998 VL 294 IS 3-4 BP 305 EP 321 DI 10.1016/S0040-1951(98)00108-5 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 138GV UT WOS:000076964400011 ER PT J AU Au, CK AF Au, CK TI The van der Waals potential in the presence of weak screening SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter AB The van der Waals potential, including its leading multipole and recoil corrections, is computed in the presence of weak screening. The Casimir correction due to the exchange of transverse photons is neglected. The general result is expressed in terms of the screening length and London-analogue two centred atomic sum rules. Explicit results in terms of the screening length are given for a pair of massive H atoms, for a positronium and a massive H atom, and for a pair of positronium atoms. C1 Univ S Carolina, Dept Phys & Astron, Columbia, SC 29208 USA. Chinese Univ Hong Kong, Dept Phys, Hong Kong, Peoples R China. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Au, CK (reprint author), Univ S Carolina, Dept Phys & Astron, Columbia, SC 29208 USA. NR 5 TC 2 Z9 2 U1 1 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD SEP 14 PY 1998 VL 31 IS 17 BP L699 EP L703 DI 10.1088/0953-4075/31/17/003 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 121FF UT WOS:000076002100003 ER PT J AU Brasselet, E Galstian, G Galstyan, TV AF Brasselet, E Galstian, G Galstyan, TV TI Optical control of isothermal phase transitions in nematic liquid crystals: strong excitation regime SO PHYSICS LETTERS A LA English DT Article DE liquid crystal; dielectric torque; polarization; light angular momentum; phase transition; molecular reorientation; orientational nonlinearity; self-modulation; optical control ID ANGULAR-MOMENTUM; LIGHT; DRIVEN; FILM AB Circular and helicoidal standing electromagnetic field induced isothermal phase transitions are observed and studied in nematic liquid crystals. Significant deviations from the case of traveling wave induced transitions are experimentally detected as far as the dynamic and hysteresis character of the transition are concerned. Optical control, e.g., formation of molecular reorientation stable and asymmetric deformation modes in circularly symmetric light fields, is achieved in the strong excitation regime. Particular self-modulation of (1) the azimuthal symmetry of light-matter interaction and of (2) the angular momentum of excitation beams is responsible for the observed behavior. (C) 1998 Elsevier Science B.V. C1 Univ Laval, Dept Phys, Ctr Opt Photon & Laser, St Foy, PQ G1K 7P4, Canada. Harvard Univ, Smithsonian Inst, Ctr Astrophys, Cambridge, MA 02138 USA. RP Galstyan, TV (reprint author), Univ Laval, Dept Phys, Ctr Opt Photon & Laser, Pav A Vachon,Cite Univ, St Foy, PQ G1K 7P4, Canada. NR 22 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD SEP 14 PY 1998 VL 246 IS 3-4 BP 367 EP 373 DI 10.1016/S0375-9601(98)00513-1 PG 7 WC Physics, Multidisciplinary SC Physics GA 119DD UT WOS:000075879500027 ER PT J AU Pen, UL AF Pen, UL TI Constructing nonlinear stochastic bias from velocity space distortions SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; galaxies : formation; large-scale structure of universe; methods : statistical ID GALAXY FORMATION; COSMIC STRUCTURE; DENSITY AB We propose a strategy to measure the dark matter power spectrum using minimal assumptions about the galaxy distribution and the galaxy-dark matter cross-correlations. We argue that on large scales the central limit theorem generically assures Gaussianity of each smoothed density field, but not coherence. Asymptotically, the only surviving parameters on a given scale are galaxy variance sigma, bias b = Omega(0.6)/beta, and the galaxy-dark matter cross-correlation coefficient r. These can all be determined by measuring the quadrupole and hexadecapole velocity distortions in the power spectrum. Measuring them simultaneously may restore consistency between all. beta-determinations independent of galaxy type. The leading deviations from Gaussianity are conveniently parameterized by an Edgeworth expansion. In the mildly nonlinear regime, two additional parameters describe the full picture: the skewness parameter s and nonlinear bias b(2). They can both be determined from the measured skewness combined with second-order perturbation theory or from an N-body simulation. By measuring the redshift distortion of the skewness, one can measure the density parameter Omega with minimal assumptions about the galaxy formation process. This formalism also provides a convenient parameterization to quantify statistical galaxy formation properties. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NR 26 TC 83 Z9 83 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 1998 VL 504 IS 2 BP 601 EP 606 DI 10.1086/306098 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KW UT WOS:000077777500001 ER PT J AU Chartas, G Chuss, D Forman, W Jones, C Shapiro, I AF Chartas, G Chuss, D Forman, W Jones, C Shapiro, I TI X-ray detection of the primary lens galaxy cluster of the gravitational lens system Q0957+561 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; quasars : individual (Q0957+561); X-rays : galaxies ID TIME-DELAY; HUBBLE-CONSTANT; DARK MATTER; LIGHT-CURVE; SPECTRA; SYSTEM-0957+561; QUASARS; MODEL; GAS AB Analysis of several recent ROSAT High-Resolution Imager (HRI) observations of the gravitationally lensed system Q0957 + 561 has led to the detection at the 3 sigma level of the cluster lens containing the primary galaxy G1. The total mass was estimated by applying the equation of hydrostatic equilibrium to the detected hot intracluster gas for a range of cluster core radii, cluster sizes, and for different values of the Hubble constant. X-ray estimates of the lensing cluster mass provide a means to determine the cluster contribution to the deflection of rays originating from the quasar Q0957 + 561. The present mass estimates were used to evaluate the convergence parameter kappa, the ratio of the local surface mass density of the cluster to the critical surface mass density for lensing. The convergence parameter kappa, calculated in the vicinity of the lensed images, was found to range between 0.07 and 0.21, depending on the assumed cluster core radius and cluster extent. This range of uncertainty in kappa does not include possible systematic errors arising from the estimation of the cluster temperature through the use of the cluster luminosity-temperature relation and the assumption of spherical symmetry of the cluster gas. Applying this range of values of re to the lensing model of Grogin & Narayan for Q0957 + 561 but not accounting for uncertainties in that model yields a range of values for the Hubble constant: 67 < H-0 < 82 km s(-1) Mpc(-1), for a time delay of 1.1 yr. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Chartas, G (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RI Chuss, David/D-8281-2012; OI Forman, William/0000-0002-9478-1682 NR 37 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 1998 VL 504 IS 2 BP 661 EP 670 DI 10.1086/306110 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KW UT WOS:000077777500007 ER PT J AU Hardcastle, MJ Lawrence, CR Worrall, DM AF Hardcastle, MJ Lawrence, CR Worrall, DM TI Extended and compact X-ray emission from the powerful radio galaxy 3C 220.1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (3C 220.1); galaxies : jets; radio continuum : galaxies; X-rays : galaxies ID CLUSTERS; IDENTIFICATIONS; CYGNUS AB We report on ROSAT HRI observations of the z = 0.61 radio galaxy 3C 220.1. The X-ray emission from this object consists of an extended component, which we attribute to luminous cluster emission, and a compact central source. The compact component is too bright to be modeled as a cooling flow under some plausible assumptions for the hot gas temperature and distribution; we suggest instead that it is directly related to the core of the radio source. The X-ray flux of the compact component is consistent with the prediction of Worrall et al. that all powerful radio galaxies should have a central jet-related X-ray emission component that is proportional in strength to the radio-core flux density. Other observations of distant 3CR radio sources are consistent with this model. C1 Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. CALTECH, Jet Prop Lab 169 506, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Hardcastle, MJ (reprint author), Univ Bristol, Dept Phys, Tyndall Ave, Bristol BS8 1TL, Avon, England. RI Hardcastle, Martin/E-2264-2012 OI Hardcastle, Martin/0000-0003-4223-1117 NR 29 TC 17 Z9 17 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 1998 VL 504 IS 2 BP 743 EP 748 DI 10.1086/306121 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KW UT WOS:000077777500014 ER PT J AU Stauffer, JR Schild, R Navascues, DBY Backman, DE Angelova, AM Kirkpatrick, JD Hambly, N Vanzi, L AF Stauffer, JR Schild, R Navascues, DBY Backman, DE Angelova, AM Kirkpatrick, JD Hambly, N Vanzi, L TI Results of a deep imaging survey of one square degree of the Pleiades for low-luminosity cluster members SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; open clusters and associations : individual (Pleiades); stars : evolution; stars : low-mass, brown dwarfs ID LOW-MASS STARS; BROWN DWARF CANDIDATES; MODEL ATMOSPHERES; SPECTRAL SEQUENCE; MAIN-SEQUENCE; SPECTROSCOPY; PHOTOMETRY; LITHIUM; AGE; SEARCH AB We have obtained relatively deep imaging in two colors, with limiting magnitudes of V similar to 22.5 and I-c similar to 21, of about one square degree of the Pleiades open cluster. Our primary goal was to identify new candidate brown dwarf members of this similar to 100 Myr-old open cluster. In the process, we have also obtained V and I-c photometry for a large number of brighter proper-motion members of the cluster for which only photographic photometry had been available up until now. We identify six candidate objects whose locations in a V versus (V-I)(c) color-magnitude diagram are consistent with their being Pleiades members near or below the hydrogen-burning mass limit. We have obtained near-infrared photometry for several of these brown dwarf candidates, as well. as for a selection of previously identified very low mass Pleiades members, and we use this new photometry to help determine whether the objects identified in the visual are indeed Pleiades members or not. Finally, we have obtained a moderate-resolution spectrum of one of the new brown dwarf candidates with the Keck LRIS spectrograph The spectrum shows that the star has a spectral type of M7 which is compatible with its photometric colors, and that it has an H alpha equivalent width of about 14 Angstrom and a marginally detected lithium 6708 Angstrom absorption equivalent width of about 0.4 Angstrom. These spectroscopic characteristics suggest that this object (MHObd1) is indeed a Pleiades member with a mass at or slightly above the hydrogen-burning mass limit. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91125 USA. Royal Observ, Edinburgh EH9 3HJ, Midlothian, Scotland. Osserv Astrofis Arcetri, I-50125 Florence, Italy. RP Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. RI Vanzi, Leonardo/D-1381-2014; Barrado Navascues, David/C-1439-2017 OI Barrado Navascues, David/0000-0002-5971-9242 NR 55 TC 40 Z9 40 U1 0 U2 0 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 SEP 10 PY 1998 VL 504 IS 2 BP 805 EP 820 DI 10.1086/306095 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KW UT WOS:000077777500019 ER PT J AU Tafalla, M Mardones, D Myers, PC Caselli, P Bachiller, R Benson, PJ AF Tafalla, M Mardones, D Myers, PC Caselli, P Bachiller, R Benson, PJ TI L1544: A starless dense core with extended inward motions SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (L1544); ISM : kinematics and dynamics; stars : formation ID MOLECULAR CLOUD CORES; YOUNG STELLAR OBJECTS; DARK CLOUDS; INTERSTELLAR CLOUDS; AMBIPOLAR DIFFUSION; NH3 OBSERVATIONS; LINE FORMATION; INFALL; PROTOSTARS; COLLAPSE AB We present a multiline study of the dense core L1544 in the Taurus molecular complex. Although L1544 does not harbor an embedded star, it presents several characteristics of cores that have already undergone star formation, suggesting that it may be rather advanced in its evolution toward becoming a star-forming core. The spectral lines from L1544 present an interesting dichotomy, with the thick dense gas tracers suffering very strong self absorption while CO and its isotopes are not being absorbed at all. The presence of the self absorptions allows us to study both the density structure and kinematics of the gas in detail. A simple analysis shows that the core is almost isothermal and that the self absorptions are due to very subthermal excitation of the dense gas tracers in the outer layers. The density has to decrease outward rapidly, and a detailed radiative transfer calculation that simultaneously fits three isotopes of CO and two of CS shows that the density approximately follows a r(-1.5) power law. The self absorptions, in addition, allow us to measure the relative velocity between the inner and outer layers of the core, and we find that there is a global pattern of inward motions (background and foreground approaching each other). The relative speed between the foreground and background changes with position, and we use a simple two-layer model to deduce that while the foreground gas has a constant velocity, the background material presents systematic velocity changes that we interpret as arising from two velocity components. We explore the origin of the inward motions by comparing our observations with models of gravitational collapse. A model in which the infall starts at the center and propagates outward las in the inside-out collapse of Shu) is inconsistent with the large extension of the absorption (that suggests an advanced age) and the lack of a star at the core center (that suggests extreme youth). Ambipolar diffusion seems also ruled out because of the large amount of the inward speed (up to 0.1 km s(-1)) and the fact that ionized species move with speeds similar to those of the neutrals. Other infall models seem also to have problems fitting the data, so if L1544 is infalling, it seems to be doing so in a manner not contemplated by the standard theories of star formation. Our study of L1544 illustrates how little is still known about the physical conditions that precede star formation and how detailed studies of starless cores are urgently needed. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. Natl Astron Observ, E-28800 Madrid, Spain. Wellesley Coll, Whitin Observ, Wellesley, MA 02181 USA. RP Tafalla, M (reprint author), Natl Astron Observ, Campus Univ,Apartado 1143, E-28800 Madrid, Spain. RI Mardones, Diego/I-5719-2016 NR 88 TC 208 Z9 209 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 1998 VL 504 IS 2 BP 900 EP 914 DI 10.1086/306115 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KW UT WOS:000077777500026 ER PT J AU Riess, AG Nugent, P Filippenko, AV Kirshner, RP Perlmutter, S AF Riess, AG Nugent, P Filippenko, AV Kirshner, RP Perlmutter, S TI Snapshot distances to type Ia supernovae: All in "one" night's work SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : distances; stars : fundamental parameters; supernovae : general ID LIGHT-CURVE SHAPES; ABSOLUTE MAGNITUDE; HUBBLE CONSTANT; SN-1991T; DIAGRAM; LAMBDA; OMEGA; DUST AB We present an empirical method that measures the distance to a Type Ia supernova (SN Ia) with a precision of similar to 10% from a single night's data. This method measures the supernova's age and luminosity/light-curve parameter from a spectrum and the extinction and distance from an apparent magnitude and color. We are able to verify the precision of this method from error propagation calculations, Monte Carlo simulations of well-sampled SNe Ia, and the Hubble diagram of sparsely observed supernovae. With the reduction in telescope time needed, this method is 3-4 times more efficient for measuring cosmological parameters than conventional light-curve-based distance estimates. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Riess, AG (reprint author), Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RI Perlmutter, Saul/I-3505-2015 OI Perlmutter, Saul/0000-0002-4436-4661 NR 45 TC 46 Z9 48 U1 1 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 1998 VL 504 IS 2 BP 935 EP 944 DI 10.1086/306106 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KW UT WOS:000077777500030 ER PT J AU Kalogera, V Kolb, U King, AR AF Kalogera, V Kolb, U King, AR TI Supernova kicks, magnetic braking, and neutron star binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : evolution; stars : neutron; supernovae : general; X-rays : stars ID X-RAY BINARIES; BLACK-HOLE BINARIES; CATACLYSMIC VARIABLES; VELOCITY DISTRIBUTION; EVOLUTION; SYSTEMS; TRANSIENTS; COMPONENT; PULSARS; NOVAE AB We consider the formation of few-mass X-ray binaries (LMXBs) containing accreting neutron stars via the helium star supernova channel. The predicted relative number of short-period transients provides a sensitive test of the input physics in this process. We investigate the effect of varying mean kick velocities, orbital angular momentum loss efficiencies, and common-envelope ejection efficiencies on the subpopulation of short-period systems, both transient and persistent. Guided by the thermal-viscous disk instability model in irradiation-dominated disks, we posit that short-period transients have donors close to the end of core hydrogen burning. We find that with increasing mean kick velocity the overall short-period fraction, s, grows, while the fraction r of systems with evolved donors among short-period systems drops. This effect, acting in opposite directions on these two fractions, allows us to constrain models of LMXB formation through comparison with observational estimates of s and r. Without fine tuning or extreme assumptions about evolutionary parameters, consistency between models and current observations is achieved for a regime of intermediate average kick magnitudes of about 100-200 km s(-1) provided that (1) orbital braking for systems with donor masses in the range 1-1.5 M-. is weak, i.e., much less effective than a simple extrapolation of standard magnetic braking beyond 1.0 M-. would suggest, and (2) the efficiency of common-envelope ejection is low. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Leicester, Astron Grp, Leicester LE1 7RH, Leics, England. Max Planck Inst Astrophys, D-85740 Garching, Germany. RP Kalogera, V (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 52 TC 26 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 1998 VL 504 IS 2 BP 967 EP 977 DI 10.1086/306119 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KW UT WOS:000077777500032 ER PT J AU Dooley, PM Lewis, BR Gibson, ST Baldwin, KGH Cosby, PC Price, JL Copeland, RA Slanger, TG Thorne, AP Murray, JE Yoshino, K AF Dooley, PM Lewis, BR Gibson, ST Baldwin, KGH Cosby, PC Price, JL Copeland, RA Slanger, TG Thorne, AP Murray, JE Yoshino, K TI A comparative high-resolution study of predissociation linewidths in the Schumann-Runge bands of O-2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ABSORPTION CROSS-SECTIONS; OSCILLATOR-STRENGTHS; VACUUM-ULTRAVIOLET; HERZBERG CONTINUUM; VALENCE STATE; REGION; O2; SPECTROSCOPY; OXYGEN; COEFFICIENTS AB Results are presented of a comparative study in which three distinct high-resolution experimental techniques (vacuum-ultraviolet laser spectroscopy, laser-induced fluorescence spectroscopy and vacuum-ultraviolet Fourier-transform spectroscopy) were used to study predissociation in the Schumann-Runge bands of O-2 B (3)Sigma(u)(-)(upsilon')<--X (3)Sigma(g)(-)(upsilon ") with upsilon' = 13 and 14. Our measurements are the first to be performed at high resolution for these levels and represent a significant advance on previous knowledge, characterizing completely the fine-structure and rotation dependencies of the B (3)Sigma(u)(-)(upsilon = 13 and 14)-state predissociation for the first time. The measured fine-structure-specific linewidths will result in significant improvements in the parameterization of models describing predissociation of the B-state and will have an impact on the development of realistic photochemical models of the terrestrial atmosphere. Good agreement was found between linewidths measured using vacuum-ultraviolet laser spectroscopy and laser-induced fluorescence spectroscopy, but unexpected difficulties arose in determining quantitative linewidths using vacuum-ultraviolet Fourier-transform spectroscopy. For each experimental technique, the instrumental resolution had to be carefully controlled and monitored in order to ensure reliable interpretation of the measured spectra. (C) 1998 American Institute of Physics. [S0021-9606(98)00734-X]. C1 Australian Natl Univ, Res Sch Phys Sci & Engn, Canberra, ACT 0200, Australia. SRI Int, Mol Phys Lab, Menlo Park, CA 94025 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Dooley, PM (reprint author), Australian Natl Univ, Res Sch Phys Sci & Engn, Canberra, ACT 0200, Australia. RI Baldwin, Kenneth/A-4928-2008; Copeland, Richard/E-2201-2011 OI Baldwin, Kenneth/0000-0002-2043-5330; NR 39 TC 21 Z9 21 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD SEP 8 PY 1998 VL 109 IS 10 BP 3856 EP 3867 DI 10.1063/1.476986 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 116HY UT WOS:000075719900016 ER PT J AU Madore, BF Freedman, WL Silbermann, N Harding, P Huchrall, J Mould, JR Graham, JA Ferrarese, L Gibson, BK Han, MS Hoessel, JG Hughes, SM Illingworth, GD Phelps, R Sakai, S Stetson, P AF Madore, BF Freedman, WL Silbermann, N Harding, P Huchrall, J Mould, JR Graham, JA Ferrarese, L Gibson, BK Han, MS Hoessel, JG Hughes, SM Illingworth, GD Phelps, R Sakai, S Stetson, P TI A Cepheid distance to the Fornax cluster and local expansion rate of the Universe SO NATURE LA English DT Article ID HUBBLE-SPACE-TELESCOPE; TULLY-FISHER RELATION; VELOCITY-FIELD; NEARBY GALAXIES; SUPERCLUSTER; POPULATION; CONSTANT; CATALOG; MODEL AB Both galaxy distances and velocities are required for the determination of the expansion rate of the Universe, as described by the Hubble constant H-0. The radial velocities of galaxies arise not just from this expansion but also from random components and large-scale flows. To reach out to distances dominated by the overall cosmic expansion, it is necessary to probe large physical scales where galaxy-galaxy and galaxy-cluster interactions become less important. But accurate distances of nearby galaxies and clusters (commonly measured(1) using Cepheid variable stars) are nevertheless required to calibrate the indirect distance indicators generally used to measure these large scales. Here we report a Cepheid distance of 18.6 +/- 1.9 (statistical error) +/- 1.9 Mpe (systematic error) for the galaxy NGC1365 in Fornax, a cluster of galaxies in the Southern Hemisphere. We find a value of H-0 = 70 km s(-1) Mpc(-1) from Fornax alone, and 73 km s(-1) Mpc.(-1) from the intervening galaxy flow, each corrected for infall into the Virgo cluster. These values are consistent with the Hubble constant measured in the far field using secondary methods(2). Our data support previous suggestions(3-5) that the local small-scale velocity field has very small scatter (similar to+/-70km s(-1)). C1 CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, NASA IPAC Extragalact Database, Pasadena, CA 91125 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Harvard Smithsonian Inst, Ctr Astrophys, Cambridge, MA 02138 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Inst Adv Studies, Weston, ACT 2611, Australia. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. CALTECH, MS Robinson Lab 105 24, Pasadena, CA 91125 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Royal Greenwich Observ, Cambridge CB3 0HA, England. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. RP Madore, BF (reprint author), CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, NASA IPAC Extragalact Database, MS 100-22, Pasadena, CA 91125 USA. EM barry@ipac.caltech.edu RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 26 TC 46 Z9 46 U1 0 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD SEP 3 PY 1998 VL 395 IS 6697 BP 47 EP 50 DI 10.1038/25678 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 116JY UT WOS:000075722200040 ER PT J AU Walker, RA AF Walker, RA TI Olowe of Ise, "Anonymous" has a name (Yoruba sculptor) SO AFRICAN ARTS LA English DT Article C1 Smithsonian Inst, Museum Africa Art, Washington, DC 20560 USA. RP Walker, RA (reprint author), Smithsonian Inst, Museum Africa Art, Washington, DC 20560 USA. NR 14 TC 2 Z9 2 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 FAL PY 1998 VL 31 IS 4 BP 38 EP + DI 10.2307/3337647 PG 0 WC Art SC Art GA 154XE UT WOS:000077914700011 ER PT J AU Ross, M Post, JE AF Ross, M Post, JE TI Memorial of Daniel E. Appleman - 1931-1998 SO AMERICAN MINERALOGIST LA English DT Biographical-Item C1 US Geol Survey, Reston, VA 20192 USA. Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. RP Ross, M (reprint author), US Geol Survey, Reston, VA 20192 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 SEP-OCT PY 1998 VL 83 IS 9-10 BP 1133 EP 1135 PG 3 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 122QL UT WOS:000076082900025 ER PT J AU Langley, HD AF Langley, HD TI Those vulgar tubes: External sanitary accommodations aboard European ships of the fifteenth through seventeenth centuries SO AMERICAN NEPTUNE LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Langley, HD (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU PEABODY MUSEUM PI SALEM PA E INDIA MARINE HALL, SALEM, MA 01970 USA SN 0003-0155 J9 AM NEPTUNE JI Am. Neptune PD FAL PY 1998 VL 58 IS 4 BP 391 EP 392 PG 2 WC History SC History GA 188GV UT WOS:000079839200009 ER PT J AU Judd, DD AF Judd, DD TI Review of a bromeliad-ovipositing lineage in Wyeomyia and the resurrection of Hystatomyia (Diptera : Culicidae) SO ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA LA English DT Article DE Sabethine mosquitoes; cladistics; total evidence; partitioned analyses; classification ID TAXONOMY AB Problems associated with the monophyly of Wyomyia Theobald we discussed and. part of the classification is revised. One problematical component of the cladogram is a lineage of primarily bromeliad-ovipositing mosquitoes that include the type species Wyeomyia grayii Theobald. When the characters used in the cladistic analysis are partitioned by life stage the arrangement displayed by the combined data does not appear among the various topologies based on a single life stage. However, further analyses support the unique arrangement From the combined data and the following changes in classification are made to reflect the pattern of relationships implied by that cladogram. Phoniomyia Theobald is reduced to a subgenus in Wyeomyia, The name Hystatomyia Dyar is resurrected for 7 species currently without subgeneric placement. Two species representing 2 well-defined groups within Hystatomyia are redescribed and illustrated in larval, pupal, and adult stages. Wyecomyia esmeraldasi (Levi-Castillo) is transferred from W. (Phoniomyia) to W. (Hystatomyia). Wyeomyia into,lca Dyar and Knab is removed as a junior synonym of Wyeomyia circumcincta Dyar and Knab. C1 Smithsonian Inst, Dept Entomol, Washington, DC 20560 USA. RP Judd, DD (reprint author), Oregon State Univ, Dept Entomol, 2046 Cordley Hall, Corvallis, OR 97331 USA. NR 54 TC 23 Z9 25 U1 0 U2 0 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 SEP PY 1998 VL 91 IS 5 BP 572 EP 589 PG 18 WC Entomology SC Entomology GA 124YW UT WOS:000076211200007 ER PT J AU Tormos, J Krombein, KV Asis, JD Gayubo, SF AF Tormos, J Krombein, KV Asis, JD Gayubo, SF TI Descriptions of mature larvae of two Amiseginae, with a discussion of larval characters in the Chrysididae (Hymenoptera) SO ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA LA English DT Article DE Chrysididae; Amiseginae; preimaginal stages AB The mature larvae of 2 species of Amiseginae - Adelphe anisomorphae Krombein and Myrmecomimesis bispinosus (Riek) - are described. These larvae share with other Chrysididae and with Bethylidae a simple atrium and an opening toward the unarmed subatrium. As in the Bethylidae, they lack a coronal suture and parietal bands. Several characters are shared with Cleptinae and Chrysidinae (Chrysididae): a labrum with sensilla and a notched anterior margin, and a well-developed peritreme. The presence of 2 antennal sensilla. and the absence of setae on labrum and maxillae are, among the Chrysididae exclusive to Amiseginae. The phylogenetic importance of these preimaginal structures is discussed. C1 Univ Salamanca, Fac Biol, Unidad Zool, Salamanca 37071, Spain. Natl Museum Nat Hist, Dept Entomol, Smithsonian Inst, Washington, DC 20560 USA. RP Tormos, J (reprint author), Univ Salamanca, Fac Biol, Unidad Zool, Salamanca 37071, Spain. RI Asis, Josep/K-5623-2014; Tormos, Jose/K-5643-2014 OI Asis, Josep/0000-0001-8134-1875; Tormos, Jose/0000-0002-0568-4486 NR 11 TC 3 Z9 3 U1 0 U2 1 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 SEP PY 1998 VL 91 IS 5 BP 598 EP 601 PG 4 WC Entomology SC Entomology GA 124YW UT WOS:000076211200009 ER PT J AU Riess, AG Filippenko, AV Challis, P Clocchiatti, A Diercks, A Garnavich, PM Gilliland, RL Hogan, CJ Jha, S Kirshner, RP Leibundgut, B Phillips, MM Reiss, D Schmidt, BP Schommer, RA Smith, RC Spyromilio, J Stubbs, C Suntzeff, NB Tonry, J AF Riess, AG Filippenko, AV Challis, P Clocchiatti, A Diercks, A Garnavich, PM Gilliland, RL Hogan, CJ Jha, S Kirshner, RP Leibundgut, B Phillips, MM Reiss, D Schmidt, BP Schommer, RA Smith, RC Spyromilio, J Stubbs, C Suntzeff, NB Tonry, J TI Observational evidence from supernovae for an accelerating universe and a cosmological constant SO ASTRONOMICAL JOURNAL LA English DT Review DE cosmology : observations; supernovae : general ID CEPHEID DISTANCE SCALE; LIGHT-CURVE SHAPES; IA SUPERNOVAE; HUBBLE DIAGRAM; GLOBULAR-CLUSTERS; PEAK BRIGHTNESS; CCD PHOTOMETRY; GALAXIES; AGE; MAGNITUDE AB We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 less than or equal to z less than or equal to 0.62. The luminosity distances of these objects are determined by methods that employ relations between SN Ia luminosity and light curve shape. Combined with previous data from our High-z Supernova Search Team and recent results by Riess et al., this expanded set of 16 high-redshift supernovae and a set of 34 nearby supernovae are used to place constraints on the following cosmological parameters: the Hubble constant (H-o), the mass density (Omega(M)), the cosmological constant (i.e., the vacuum energy density, Omega(Lambda)), the deceleration parameter (q(o)), and the dynamical age of the universe (t(o)). The distances of the high-redshift SNe Ia are, on average, 10%-15% farther than expected in a low mass density (Omega(M) = 0.2) universe without a cosmological constant. Different light curve fitting methods, SN Ia subsamples, and prior constraints unanimously favor eternally expanding models with positive cosmological constant (i.e., Omega(Lambda) > 0) and a current acceleration of the expansion (i.e., q(o) < 0). With no prior constraint on mass density other than Omega(M) greater than or equal to 0, the spectroscopically confirmed SNe Ia are statistically consistent with q(o) < 0 at the 2.8 sigma and 3.9 sigma confidence levels, and with Omega(Lambda) > 0 at the 3.0 sigma and 4.0 sigma confidence levels, for two different fitting methods, respectively. Fixing a "minimal" mass density, Omega(M) = 0.2, results in the weakest detection, Omega(Lambda) > 0 at the 3.0 sigma confidence level from one of the two methods. For a flat universe prior (Omega(M) + Omega(Lambda) = 1), the spectroscopically confirmed SNe Ia require Omega(Lambda) > 0 at 7 sigma and 9 sigma formal statistical significance for the two different fitting methods. A universe closed by ordinary matter (i.e., Omega(M) = 1) is formally ruled out at the 7 sigma to 8 sigma confidence level for the two different fitting methods. We estimate the dynamical age of the universe to be 14.2 +/- 1.7 Gyr including systematic uncertainties in the current Cepheid distance scale. We estimate the likely effect of several sources of systematic error, including progenitor and metallicity evolution, extinction, sample selection bias, local perturbations in the expansion rate, gravitational lensing, and sample contamination. Presently, none of these effects appear to reconcile the data with Omega(Lambda) = 0 and q(o) greater than or equal to 0. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. European So Observ, D-85748 Garching, Germany. Cerro Tololo Interamer Observ, Natl Opt Astron Observ, La Serena, Chile. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Riess, AG (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Stubbs, Christopher/C-2829-2012; OI Stubbs, Christopher/0000-0003-0347-1724; Schmidt, Brian/0000-0001-6589-1287 NR 131 TC 8951 Z9 9041 U1 48 U2 264 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD SEP PY 1998 VL 116 IS 3 BP 1009 EP 1038 DI 10.1086/300499 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 121XG UT WOS:000076040700001 ER PT J AU Turner, JL Ho, PTP Beck, SC AF Turner, JL Ho, PTP Beck, SC TI The radio properties of NGC 5253 and its unusual H II regions SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : dwarf; galaxies : evolution; galaxies : individual (NGC 5253); galaxies : ISM; galaxies : starburst ID STARBURST GALAXY NGC-5253; STAR-FORMATION; MAGELLANIC CLOUDS; MASSIVE STARS; CONTINUUM; SPECTROSCOPY; ENRICHMENT; EMISSION; NGC-253; FIELD AB We present VLA. images of the radio continuum emission of the starburst in NGC 5253 at wavelengths of 6, 3.6, and 2 cm, with resolutions of 1 "-2 ", and at 20 cm with resolution of similar to 9 ". A spectral index map constructed from the 6 and 2 cm images indicates that thermal free-free emission from ionized gas, most of it from a single source, dominates the radio emission. The unusually high fraction of free-free emission suggests that the starburst is very young. Regions of diffuse nonthermal synchrotron emission and probable supernova remnants surround the central radio source. We detect several regions of rising spectral index in NGC 5253, suggesting that the free-free emission is optically thick at 2 cm. These nebulae are situated to the north of the central cluster/main radio source. The turnover frequencies require an emission measure (EM) similar to 10(8)-10(9) cm(-6) pc, and [n(e)(2)](1/2) similar to 10(4)-10(5) cm(-3). From the observed intensities, we infer diameters of a few tenths of a parsec for these regions, which is an order of magnitude larger than the diameters of H II regions of comparable density in the Galaxy. Lyman continuum rates of over N-Lyc similar to 10(51) s(-1) are required to ionize these high densities and volumes. Unlike Galactic compact H II regions, which contain no more than a few O stars, the optically thick H rr. regions in NGC 5253 are excited by an estimated 200-1000 O stars each. This is consistent with the idea that very large clusters are the mode of star formation in the central region of NGC 5253. The optically thick H II regions, located to the north of the dominant optical and radio sources, may well trace the very youngest parts of the starburst. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Tel Aviv Univ, Dept Astron & Astrophys, IL-69989 Tel Aviv, Israel. RP Turner, JL (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NR 41 TC 86 Z9 86 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD SEP PY 1998 VL 116 IS 3 BP 1212 EP 1220 DI 10.1086/300485 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 121XG UT WOS:000076040700015 ER PT J AU Noriega-Crespo, A Garnavich, PM Molinari, S AF Noriega-Crespo, A Garnavich, PM Molinari, S TI Isocam molecular hydrogen images of the Cepheus E outflow SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; ISM : jets and outflows; stars : formation; stars : pre-main-sequence ID CEP-E; DUST; EMISSION; OBJECTS; CLOUD AB The physical characteristics of the Cepheus E "embedded" outflow are analyzed using ISOCAM images in the upsilon = 0-0 S(5) 6.91 mu m and S(3) 9.66 mu m molecular hydrogen lines. We find that the morphology of the Cep E outflow in the ground vibrational H-2 lines is similar to that in the near-infrared upsilon = 1-0 2.12 mu m line. At these mid-infrared wavelengths, we detect neither the second H-2 outflow that is almost perpendicular to the Cep E 2.12 mu m flow nor traces of H-2 emission along the second (CO)-C-12 J = 2-1 outflow, at an angle of similar to 52 degrees, down to a surface brightness of 12-46 mu Jy arcsec(-2). We do detect at 6.91 mu m the likely source of the main H-2 and CO outflows, IRAS 23011 + 6126, and show that the source is easily seen in all IRAS bands using HIRES images. The source is not detected at 9.66 mu m, but we think this agrees with the interstellar extinction curve, which has a minimum at similar to 7 mu m but rises at similar to 9.7 mu m as a result of the strong absorption silicate feature, enhanced in this case by a cocoon surrounding the Class 0 object. This idea is supported by our models of the spectral energy distribution (SED) of the central object. The models assume that the main source of opacity is due to bare silicates, and our best fit for the SED yields a total envelope mass of 17 M. and a dust temperature of 18 K. C1 CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Noriega-Crespo, A (reprint author), CALTECH, Ctr Infrared Proc & Anal, Mail Stop 100-22, Pasadena, CA 91125 USA. RI Molinari, Sergio/O-4095-2016 OI Molinari, Sergio/0000-0002-9826-7525 NR 21 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD SEP PY 1998 VL 116 IS 3 BP 1388 EP 1395 DI 10.1086/300521 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 121XG UT WOS:000076040700032 ER PT J AU Franz, OG Henry, TJ Wasserman, LH Benedict, GF Ianna, PA Kirkpatrick, JD McCarthy, DW Bradley, AJ Duncombe, RL Fredrick, LW Hemenway, PD Jefferys, WH McArthur, BE Nelan, EP Shelus, PJ Story, DB van Altena, WF Whipple, AL AF Franz, OG Henry, TJ Wasserman, LH Benedict, GF Ianna, PA Kirkpatrick, JD McCarthy, DW Bradley, AJ Duncombe, RL Fredrick, LW Hemenway, PD Jefferys, WH McArthur, BE Nelan, EP Shelus, PJ Story, DB van Altena, WF Whipple, AL TI The first definitive binary orbit determined with the Hubble Space Telescope Fine Guidance Sensors: Wolf 1062 (Gliese 748) SO ASTRONOMICAL JOURNAL LA English DT Article DE astrometry; binaries : close; stars : fundamental parameters; stars : individual (Wolf 1062); stars : low-mass, brown dwarfs ID LOW-MASS STARS; SEQUENCE AB The M dwarf binary, Wolf 1062 (Gliese 748), has been observed with the Hubble Space Telescope (HST) Fine Guidance Sensor 3 in the transfer function scan mode to determine the apparent orbit. This is the first orbit defined fully and exclusively with HST, and is the most accurate definitive orbit for any resolved, noneclipsing system. The orbital period is 2.4490 +/- 0.0119 yr and the semimajor axis is 0." 1470 +/- 0." 0007-both quantities are now known to better than 1%. Using the weighted mean of seven parallax measurements and these HST data, we find the system mass to be 0.543 +/- 0.031 M., where the error of 6% is due almost entirely to the parallax error. An estimated fractional mass from the infrared brightness ratio and infrared mass-luminosity relation yields a mass for the primary of 0.37 M., and the secondary falls in the regime of very low mass stars, with a mass of only 0.17 M.. C1 Lowell Observ, Flagstaff, AZ 86001 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Allied Signal Aerosp Co, Greenbelt, MD 20770 USA. Univ Texas, Dept Aerosp Engn, Austin, TX 78712 USA. Univ Rhode Isl, Dept Phys, Kingston, RI 02881 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Jackosn & Tull Chartered Engineers, Lanham, MD 20706 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. RP Franz, OG (reprint author), Lowell Observ, 1400 W Mars Hill Rd, Flagstaff, AZ 86001 USA. NR 22 TC 30 Z9 30 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD SEP PY 1998 VL 116 IS 3 BP 1432 EP 1439 DI 10.1086/300500 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 121XG UT WOS:000076040700036 ER PT J AU Barmby, P Huchra, JP AF Barmby, P Huchra, JP TI Kinematics of the Hercules supercluster (vol 115, pg 6, 1998) SO ASTRONOMICAL JOURNAL LA English DT Correction C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 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 1 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD SEP PY 1998 VL 116 IS 3 BP 1508 EP 1508 DI 10.1086/300487 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 121XG UT WOS:000076040700045 ER PT J AU Gomez, M Lada, CJ AF Gomez, M Lada, CJ TI From head to sword: The clustering properties of stars in Orion (vol 115, pg 1524, 1998) SO ASTRONOMICAL JOURNAL LA English DT Correction C1 Univ Nacl Cordoba, Astron Observ, RA-5000 Cordoba, Argentina. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Gomez, M (reprint author), Univ Nacl Cordoba, Astron Observ, RA-5000 Cordoba, Argentina. NR 1 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD SEP PY 1998 VL 116 IS 3 BP 1508 EP 1508 DI 10.1086/300486 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 121XG UT WOS:000076040700046 ER PT J AU Markevitch, M AF Markevitch, M TI The L-x-T relation and temperature function for nearby clusters revisited SO ASTROPHYSICAL JOURNAL LA English DT Article DE cooling flows; galaxies : clusters : general; intergalactic medium; X-rays : galaxies ID FLUX-LIMITED SAMPLE; POWER SPECTRUM; COOLING FLOWS; RICH CLUSTERS; RAY-CLUSTERS; GALAXIES; EVOLUTION; CONDENSATION; ENRICHMENT; OMEGA AB The X-ray luminosity-temperature relation for nearby T similar or equal to 3.5-10 keV clusters is rederived using new ASCA temperatures and ROSAT luminosities. Both quantities are derived by directly excluding the cooling how regions. This correction results in a greatly reduced scatter in the L-X-T relation; cooling how clusters are similar to others outside the small cooling how regions. For a fit of the form L-bol infinity T-alpha, we obtain alpha = 2.64 +/- 0.27 (90%) and a residual rms scatter in log L-bol of 0.10. The derived relation can be directly compared to theoretical predictions that do not include radiative cooling. It also provides an accurate reference point for future evolution searches and comparison to cooler clusters. The new temperatures and L-X-T relation together with a newly selected cluster sample are used to update the temperature function at z similar to 0.05. The resulting function is generally higher and flatter than, although within the errors of, the previous estimates by Edge and coworkers and Henry and Arnaud (as rederived by Eke and coworkers). For a qualitative estimate of constraints that the new data place on the density fluctuation spectrum, we apply the Press-Schechter formalism for Omega(0) = 1 and 0.3. For Omega(0) = 1, assuming cluster isothermality, the temperature function implies sigma(8) = 0.55 +/- 0.03, while taking into account the observed cluster temperature profiles, sigma(8) = 0.51 +/- 0.03, consistent with the previously derived range. The dependence of sigma(8) on Omega(0) is different from the earlier results because of our treatment of the slope of the fluctuation spectrum, n, as a free parameter. For the considered values of Omega(0), n = -(2.0-2.3)+/- 0.3, somewhat steeper than that derived from the earlier temperature function data, in agreement with the local slope of the galaxy fluctuation spectrum from the Automatic Plate Measuring Facility (APM) survey, and significantly steeper than the standard cold dark matter prediction. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Markevitch, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 46 TC 480 Z9 482 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP 27 EP 34 DI 10.1086/306080 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KT UT WOS:000077777200004 ER PT J AU Pinsonneault, MH Stauffer, J Soderblom, DR King, JR Hanson, RB AF Pinsonneault, MH Stauffer, J Soderblom, DR King, JR Hanson, RB TI The problem of Hipparcos distances to open clusters. I. Constraints from multicolor main-sequence fitting SO ASTROPHYSICAL JOURNAL LA English DT Article DE Hertzsprung-Russell diagram; open clusters and associations : general; stars : abundances; stars : distances; stars : evolution ID LOW-MASS STARS; ALPHA-PERSEI CLUSTER; H-BETA PHOTOMETRY; PLEIADES CLUSTER; ROTATIONAL VELOCITIES; CHEMICAL-COMPOSITION; HELIUM ABUNDANCE; B-TYPE; HYADES; EVOLUTION AB Parallax data from the Hipparcos mission allow the direct distance to open clusters to be compared with the distance inferred from main-sequence (RIS) fitting. There are surprising differences between the two distance measurements, indicating either the need for changes in the cluster compositions or reddening, underlying problems with the technique of MS fitting, or systematic errors in the Hipparcos parallaxes at the 1 mas level. We examine the different possibilities, focusing on MS fitting in both metallicity-sensitive B-V and metallicity-insensitive V-I for five well-studied systems (the Hyades, Pleiades, alpha Per, Praesepe, and Coma Ber). The Hipparcos distances to the Hyades and alpha Per are within 1 sigma of the MS-fitting distance in B-V and V-I, while the Hipparcos distances to Coma Ber and the Pleiades are in disagreement with the MS-fitting distance at more than the 3 sigma level. There are two Hipparcos measurements of the distance to Praesepe; one is in good agreement with the MS-fitting distance and the other disagrees at the 2 sigma level. The distance estimates from the different colors are in conflict with one another for Coma but in agreement for the Pleiades. Changes in the relative cluster metal abundances, age related effects, helium, and reddening are shown to be unlikely to explain the puzzling behavior of the Pleiades. We present evidence for spatially dependent systematic errors at the 1 mas level in the parallaxes of Pleiades stars. The implications of this result are discussed. C1 Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. RP Ohio State Univ, Dept Astron, 174 W 18Th Ave, Columbus, OH 43210 USA. NR 85 TC 194 Z9 195 U1 0 U2 0 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 SEP 1 PY 1998 VL 504 IS 1 BP 170 EP 191 DI 10.1086/306077 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KT UT WOS:000077777200017 ER PT J AU Soderblom, DR King, JR Hanson, RB Jones, BF Fischer, D Stauffer, JR Pinsonneault, MH AF Soderblom, DR King, JR Hanson, RB Jones, BF Fischer, D Stauffer, JR Pinsonneault, MH TI The problem of Hipparcos distances to open clusters. II. Constraints from nearby field stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE open clusters and associations : individual (Pleiades); solar neighborhood; stars : distances; stars : evolution; stars : Hertzsprung-Russell diagram ID SOLAR-TYPE STARS; CHROMOSPHERIC EMISSION; FE/H DETERMINATIONS; MAIN-SEQUENCE; NEIGHBORHOOD; PLEIADES; PHOTOMETRY; CATALOG; EDITION AB This paper examines the discrepancy between distances to nearby open clusters as determined by parallaxes from Hipparcos compared to traditional main-sequence fitting. The biggest difference is seen for the Pleiades, and our hypothesis is that if the Hipparcos distance to the Pleiades is correct, then similar subluminous zero-age main-sequence (ZAMS) stars should exist elsewhere, including in the immediate solar neighborhood. We examine a color-magnitude diagram of very young and nearby solar-type stars and show that none of them lie below the traditional ZAMS, despite the fact that the Hipparcos Pleiades parallax would place its members 0.3 mag below that ZAMS. We also present analyses and observations of solar-type stars that do lie below the ZAMS, and are show that they are subluminous because of low metallicity and that they have the kinematics of old stars. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94132 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Soderblom, DR (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM soderblom@stsci.edu; jking@stsci.edu; hanson@ucolick.org; jones@ucolick.org; fischer@stars.sfsu.edu; stauffer@cfa.harvard.edu; pinsono@astronomy.ohio-state.edu OI Fischer, Debra/0000-0003-2221-0861 NR 29 TC 46 Z9 46 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP 192 EP 199 DI 10.1086/306073 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KT UT WOS:000077777200018 ER PT J AU Goodman, AA Barranco, JA Wilner, DJ Heyer, MH AF Goodman, AA Barranco, JA Wilner, DJ Heyer, MH TI Coherence in dense cores. II. The transition to coherence SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : kinematics and dynamics; ISM : structure; line : profiles ID MOLECULAR CLOUD COMPLEXES; MAGNETIC-FIELD STRENGTH; AMBIPOLAR DIFFUSION; STAR-FORMATION; DARK CLOUDS; INTERSTELLAR CLOUDS; LINE-WIDTH; AXISYMMETRICAL SOLUTIONS; STATISTICAL-ANALYSIS; HYDROMAGNETIC-WAVES AB After studying how line width depends on spatial scale in low-mass star-forming regions, we propose that "dense cores" (Myers & Benson 1983) represent an inner scale of a self-similar process that characterizes larger scale molecular clouds. In the process of coming to this conclusion, we define four distinct types of line width-size relation (Delta upsilon proportional to R-ai), which have power-law slopes a(1), a(2), a(3), and a(4), as follows: Type 1-multitracer, multicloud intercomparison; Type 2-single-tracer, multicloud intercomparison; Type 3-multitracer study of a single cloud; and Type 4-single-tracer study of a single cloud. Type 1 studies (of which Larson 1981 is the seminal example) are compendia of Type 3 studies which illustrate the range of variation in the line width-size relation from one region to another. Using new measurements of the OH and (CO)-O-18 emission emanating from the environs of several of the dense cores studied in NH3 by Barranco & Goodman (1998; Paper I), we show that line width increases with size outside the cores with a(4) similar to 0.2. On scales larger than those traced by (CO)-O-18 or OH, (CO)-C-12 and (CO)-C-13 observations indicate that a(4) increases to similar to 0.5 (Heyer & Schloerb 1997). By contrast, within the half-power contour of the NH3 emission from the cores, line width is virtually constant, with a(4) similar to 0. We interpret the correlation between increasing density and decreasing Type 4 power-law slope as a "transition to coherence." Our data indicate that the radius R-coh at which the gas becomes coherent (i.e., a(4) --> 0) is of order 0.1 pc in regions forming primarily low-mass stars. The value of the nonthermal line width at which "coherence" is established is always less than but still of order of the thermal line width of H-2. Thus coherent cores are similar to, but not exactly the same as, isothermal balls of gas. Two other results bolster our proposal that a transition to coherence takes place at similar to 0.1 pc. First, the OH, (CO)-O-18, and NH3 maps show that the dependence of column density on size is much steeper (N proportional to R-0.9) inside R-coh than outside of it (N proportional to R-0.2), Which implies that the volume filling factor of coherent cores is much larger than in their surroundings. Second, Larson (1995) has recently found a break in the power law characterizing the clustering of stars in Taurus at 0.04 pc, just inside of R-coh. Larson and we interpret this break in slope as the point at which stellar clustering properties change from being determined by the (fractal) gas distribution (on scales greater than 0.04 pc) to being determined by fragmentation processes within coherent cores (on scales less than 0.04 pc). We speculate that the transition to coherence takes place when a dissipation threshold for the MHD turbulence that characterizes the larger scale medium is crossed at the critical inner scale R-coh. We suggest that the most likely explanation for this threshold is the marked decline in the coupling of the magnetic field to gas motions due to a decreased ion/neutral ratio in dense, high filling factor gas. C1 Harvard Univ, Dept Astron, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Massachusetts, Five Coll Radio Astron Observ, Amherst, MA 01003 USA. RP Goodman, AA (reprint author), Harvard Univ, Dept Astron, Cambridge, MA 02138 USA. RI Goodman, Alyssa/A-6007-2010 OI Goodman, Alyssa/0000-0003-1312-0477 NR 87 TC 229 Z9 229 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP 223 EP 246 DI 10.1086/306045 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KT UT WOS:000077777200021 ER PT J AU Magnani, L Onello, JS Adams, NG Hartmann, D Thaddeus, P AF Magnani, L Onello, JS Adams, NG Hartmann, D Thaddeus, P TI The variation of the CO to H-2 conversion factor in two translucent clouds SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : molecules; radio lines : ISM ID LATITUDE MOLECULAR CLOUDS; DIFFUSE INTERSTELLAR CLOUDS; INTER-STELLAR CLOUDS; RADIO OBSERVATIONS; ZETA-OPHIUCHI; CH; ABSORPTION; ABUNDANCES; CHEMISTRY; HYDROGEN AB The conversion factor, X-CO, between the velocity-integrated CO(1-0) antenna temperature, W(CO), and the H-2 column density, N(H-2), is determined for 32 positions in two translucent high-latitude molecular clouds. MBM 40 and MBM 16. X-CO is calculated using CH observations of the (2)Pi(1/2) F = 1-1 hyperfine transition to infer N(H-2). The latter quantity, divided by W(CO) yields X-CO for various positions across the clouds. We observed 24 positions in MBM 16, and X-CO values were derived in the range (1.6-17.3)x 10(20) cm(-2) O( km s(-1))(-1), with a mean value of 7.6 x 10(20). Eleven lines of sight were sampled in MBM 40 yielding values of X-CO in the range (0.7-9.7)x 10(20), with a mean value of 2.6 x 10(20). An inverse relationship between X-CO and W(CO) may exist, suggesting that the variation in X-CO for these two translucent clouds arises from varying CO abundances. This paper also reports the existence of a broad component in the CH spectra observed throughout much of MBM 16. This component possibly originates in the disturbed outer regions of the cloud where the gas is not gravitationally bound to the core of the cloud. It is unclear how sensitive the CO rotational transitions are to this component, but it is likely that the CO/H-2 ratio in this broad-line gas is less than 10(-5). However, if the CH/H-2 ratio is the same for the gas in the extended wings as it is for the typical cloud gas, then up to 40% of the cloud mass could be contained in this difficult to trace molecular component. C1 Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. SUNY Coll Cortland, Dept Phys, Cortland, NY 13045 USA. Univ Georgia, Dept Chem, Athens, GA 30602 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Magnani, L (reprint author), Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. NR 49 TC 23 Z9 23 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP 290 EP 299 DI 10.1086/306062 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KT UT WOS:000077777200025 ER PT J AU Goetz, JA Pipher, JL Forrest, WJ Watson, DM Raines, SN Woodward, CE Greenhouse, MA Smith, HA Hughes, VA Fischer, J AF Goetz, JA Pipher, JL Forrest, WJ Watson, DM Raines, SN Woodward, CE Greenhouse, MA Smith, HA Hughes, VA Fischer, J TI Cepheus A East: Unraveling the mysteries SO ASTROPHYSICAL JOURNAL LA English DT Article DE H II regions; infrared : stars; ISM : individual (Cepheus A East); ISM : molecules; stars : formation; stars : pre-main-sequence ID STAR-FORMING REGION; HERBIG-HARO OBJECTS; THERMAL RADIO JET; NEAR-INFRARED EMISSION; MOLECULAR OUTFLOWS; REFLECTION NEBULAE; VELOCITY; CLOUDS; POLARIMETRY; ARRAYS AB New infrared images of Cep A East are presented that show two regions of shock-excited line emission from separate bipolar hows. We identify the dominant sources powering the outflows and argue that the results support a multiple outflow model (Narayanan gr Walker) as opposed to a quadrupolar outflow scenario. The images include near-infrared broadband (jr [2.158 mu m], L " [3.81 mu m], and M' [4.67 mu m]) and spectral line ([Fe II] emission line at 1.644 mu m and H-2 1-0 S[1] line at 2.122 mu m) observations, as well as continuum emission, at 1.644 mu m and 2.122 mu m. Considering our data and other results, we present a unified, self-consistent picture of the disk and shock structure. The northern emission region appears to be the result of the ablation of a dense molecular clump (coincident with HW 6) in the path of a diverting jet from YSO HW 2 and subsequent multiple bow shocks with prompt entrainment arising from the interaction of the jet with the molecular cloud Cep A-2. The southern line emission region near HW 7 resembles the "artillery shell" bow shocks found in Orion and is most likely a J-type shock caused by a jet from another YSO, possibly HW 3(d)ii. C1 Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. Univ Rochester, CEK Mees Observ, Rochester, NY 14627 USA. Univ Wyoming, Wyoming Infrared Observ, Dept Phys & Astron, Laramie, WY 82071 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Queens Univ, Dept Phys, Astron Grp, Kingston, ON K7L 3N6, Canada. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. RP Goetz, JA (reprint author), Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. NR 69 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP 359 EP 374 DI 10.1086/306058 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KT UT WOS:000077777200030 ER PT J AU Popham, R Gammie, CF AF Popham, R Gammie, CF TI Advection-dominated accretion flows in the Kerr metric. II. Steady state global solutions SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; relativity ID BLACK-HOLES; VISCOUS ACCRETION; DISKS AB In a previous paper, we have written equations describing steady state, optically thin, advection-dominated accretion onto a Kerr black hole. In this paper, we survey the numerical solutions to these equations. We find that the temperature and density of the gas in the inner part of the accretion how depend strongly on the black hole spin parameter a. The rate of angular momentum accretion is also shown to depend on a; for a greater than an equilibrium spin parameter a(eq), the black hole is de-spun by the accretion how. We also investigate the dependence of the how on the angular momentum transport efficiency alpha, the advected fraction of the dissipated energy f, and the adiabatic index gamma. We find solutions for -1 < a < 1, 10(-4) less than or equal to alpha less than or equal to 0.44, 0.01 less than or equal to f less than or equal to 1, and 4/3 < gamma < 5/3. For low values of alpha and f, the inner part of the flow exhibits a pressure maximum and appears similar to equilibrium thick disk solutions. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Max Planck Inst Astrophys, D-85740 Garching, Germany. Isaac Newton Inst, Cambridge CB3 0EH, England. RP Popham, R (reprint author), Harvard Smithsonian Ctr Astrophys, MS-51,60 Garden St, Cambridge, MA 02138 USA. NR 30 TC 82 Z9 83 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP 419 EP 430 DI 10.1086/306054 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KT UT WOS:000077777200035 ER PT J AU Luhman, ML Satyapal, S Fischer, J Wolfire, MG Cox, P Lord, SD Smith, HA Stacey, GJ Unger, SJ AF Luhman, ML Satyapal, S Fischer, J Wolfire, MG Cox, P Lord, SD Smith, HA Stacey, GJ Unger, SJ TI Infrared Space Observatory measurements of a [C II] 158 micron line deficit in ultraluminous infrared galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : ISM; galaxies : starburst; infrared : galaxies; infrared : ISM : lines and bands; ISM : atoms ID LONG-WAVELENGTH SPECTROMETER; PHOTODISSOCIATION REGIONS; INTERSTELLAR-MEDIUM; GALACTIC NUCLEI; MOLECULAR GAS; EMISSION; SPECTROSCOPY; TRANSITION; ORIGIN; FIELD AB We report measurements of the [C II] 157.74 mu m fine-structure line in a sample of seven ultraluminous infrared galaxies (ULIGs) (L-1R > 10(12) L-.) with the Long Wavelength Spectrometer on the Infrared Space Observatory. The [C II] line is an important coolant in galaxies and arises in interstellar gas exposed to far-ultraviolet photons (hv greater than or equal to 11.26 eV); in ULIGs, this radiation stems from the bursts of star formation and/or from the active galactic nuclei that power the tremendous infrared luminosity. The [C II] 158 mu m line is detected in four of the seven ULIGs; the absolute line flux (about a few times 10(-20) W cm(-2)) represents some of the faintest extragalactic [C II] emission yet observed. Relative to the far-infrared continuum, the [C II] flux from the observed ULIGs is similar to 10% of that seen from nearby normal and starburst galaxies. We discuss possible causes for the [C II] deficit, namely (1) self-absorbed or optically thick [C II] emission, (2) saturation of the [C II] emission in photodissociated gas with high gas density n (much greater than 3 x 10(3) cm(-3)) or with a high ratio of incident W flux G(o) to n (G(o)/n greater than or similar to 10 cm(3)), or (3) the presence of a soft ultraviolet radiation field caused, for example, by a stellar population deficient in massive main-sequence stars. As nearby examples of colliding galaxies, ULIGs may resemble high-redshift protogalaxies in both morphology and spectral behavior. If true, the suggested [C II] deficit in ULIGs poses limitations on the detection rate of high-z sources and on the usefulness of [C II] as an eventual tracer of protogalaxies. C1 USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Towson State Univ, Dept Phys, Towson, MD 21252 USA. Univ Paris 11, Inst Astrophys Spatiale, Orsay, France. CALTECH, IPAC, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ London Queen Mary & Westfield Coll, London, England. RP Luhman, ML (reprint author), USN, Res Lab, Remote Sensing Div, Code 7217, Washington, DC 20375 USA. NR 48 TC 120 Z9 120 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP L11 EP L15 DI 10.1086/311562 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KV UT WOS:000077777400003 ER PT J AU Wijnands, R Mendez, M van der Klis, M Psaltis, D Kuulkers, E Lamb, FK AF Wijnands, R Mendez, M van der Klis, M Psaltis, D Kuulkers, E Lamb, FK TI Discovery of kilohertz quasi-periodic oscillations in the Z source GX 5-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (GX 5 -1); stars : neutron; X-rays : stars ID X-RAY FLUX; BEHAVIOR; GX5-1 AB We discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the bright low-mass X-ray binary and Z source GX 5-1 with the Rossi X-ray Timing Explorer. In the X-ray color-color and hardness-intensity diagram a clear Z track is traced out, which shifted between observations. The frequencies of the two kHz QPOs increased from similar to 215 and similar to 500 Hz on the left part of the horizontal branch to similar to 700 and similar to 890 Hz, respectively, on the upper part of the normal branch. With increasing frequency the FWHM and rms amplitude (8.6-60 keV) of the higher frequency 1kHz QPO decreased from 300 to 30 Hz, and from 6.6% to 2.4%, respectively. The FWHM and amplitude of the lower frequency kHz QPO (50-100 Hz and 3%-4% rms) did not correlate with the position of the source on the Z track. The kHz QPO separation was consistent with being constant at 298 +/- 11 Hz. Simultaneously with the kHz QPOs horizontal branch oscillations were detected with frequencies between 18 and 56 Hz. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Natl Univ La Plata, Fac Ciencias Astron & Geofis, RA-1900 La Plata, Argentina. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Oxford, Nucl & Astrophys Lab, Oxford OX1 3RH, England. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. RP Wijnands, R (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. RI Mendez, Mariano/C-8011-2012 OI Mendez, Mariano/0000-0003-2187-2708 NR 22 TC 35 Z9 35 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 1 PY 1998 VL 504 IS 1 BP L35 EP L38 DI 10.1086/311564 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KV UT WOS:000077777400008 ER PT J AU Radick, RR Lockwood, GW Skiff, BA Baliunas, SL AF Radick, RR Lockwood, GW Skiff, BA Baliunas, SL TI Patterns of variation among sun-like stars SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE stars, activity; stars, late-type; stars, variables, other ID MAIN-SEQUENCE STARS; CA-II H; COOL STARS; CHROMOSPHERIC VARIATIONS; MAGNETIC-STRUCTURE; SOLAR; EMISSION; IRRADIANCE; ROTATION AB We examine the patterns of variation among a sample of 35 stars that includes the Sun, particularly on the timescale of the 11 yr solar activity cycle. Our investigation uses contemporaneous photometric and chromospheric HK emission time series measurements from the Lowell and Mount Wilson Observatories, and comparable solar data. We find that the photometric and HK variability of the stars in our sample can be related to their average level of chromospheric activity by power laws. The photometric variability of the Sun may be somewhat subdued for its average activity level. We find that the younger, more active stars in our sample tend to become fainter as their HK emission increases, whereas the older, less active stars tend to become brighter as their HK emission increases, as the Sun does during its activity cycle. C1 Natl Solar Observ, Air Force Lab, Space Hazards Branch, Sunspot, NM 88349 USA. Lowell Observ, Flagstaff, AZ 86001 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Radick, RR (reprint author), Natl Solar Observ, Air Force Lab, Space Hazards Branch, Sunspot, NM 88349 USA. EM radick@sunspot.noao.edu; gwl@lowell.edu; bas@lowell.edu; baliunas@cfa.harvard.edu NR 25 TC 177 Z9 178 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD SEP PY 1998 VL 118 IS 1 BP 239 EP 258 DI 10.1086/313135 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 119UE UT WOS:000075915400006 ER PT J AU Travers, SE Gilbert, GS Perry, EF AF Travers, SE Gilbert, GS Perry, EF TI The effect of rust infection on reproduction in a tropical tree (Faramea occidentalis) SO BIOTROPICA LA English DT Article DE Aecidium faramea; Faramea occidentalis; fruit abortion; fruit production; plant-pathogen interactions ID ANTHER-SMUT INFECTION; SILENE-ALBA; USTILAGO-VIOLACEA; DISEASE; POPULATION; FUNGUS AB Fungal pathogens that infect reproductive structures of plants (e.g., flowers and fruits) can reduce the seed production and seedling recruitment of host plants. We report here on the effects of a rust, Aecidium farameae that infects the ovaries and pedicels of mature flowers on Faramea occidentalis (Rubiaceae), a small tree common on Barro Colorado Island, Republic of Panama. Rust infection of ovaries reduced the number of maturing fruit on infected trees. Trees with low rust incidence in June of 1992 had 68 percent fruit survival, compared to 17 percent fruit survival for those with high rust incidence. Infected fruits developed abnormally and were usually aborted long before uninfected fruits were mature. One hundred percent of the infected ovaries marked in July were diseased or missing in August. We conclude that infection by A. farameae has the potential to seriously decrease the reproductive output of Faramea occidentalis and may represent an important source of variation in the relative fitness of individual plants. C1 Univ Calif Santa Barbara, Dept Ecol Evolut & Marine Biol, Santa Barbara, CA 93106 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Gilbert, GS (reprint author), Univ Calif Berkeley, Dept Environm Sci Policy & Management, 151 Hilgard Hall 3110, Berkeley, CA 94720 USA. NR 22 TC 4 Z9 6 U1 1 U2 5 PU ASSOC TROPICAL BIOLOGY INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0006-3606 J9 BIOTROPICA JI Biotropica PD SEP PY 1998 VL 30 IS 3 BP 438 EP 443 DI 10.1111/j.1744-7429.1998.tb00077.x PG 6 WC Ecology SC Environmental Sciences & Ecology GA 127ZZ UT WOS:000076381900010 ER PT J AU Smith, RW AF Smith, RW TI An autobiography and other recollections, 2nd edition SO BRITISH JOURNAL FOR THE HISTORY OF SCIENCE LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Smith, RW (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0007-0874 J9 BRIT J HIST SCI JI Br. J. Hist. Sci. PD SEP PY 1998 VL 31 IS 110 BP 372 EP 373 PN 3 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA 136VM UT WOS:000076879900014 ER PT J AU Diaz, GA Manning, RB AF Diaz, GA Manning, RB TI The last pelagic stage and juvenile of Lysiosquilla scabricauda (Lamarck, 1818) (Crustacea, Stomatopoda) SO BULLETIN OF MARINE SCIENCE LA English DT Article C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, Miami, FL 33149 USA. Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. RP Diaz, GA (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. NR 9 TC 1 Z9 3 U1 0 U2 1 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 EI 1553-6955 J9 B MAR SCI JI Bull. Mar. Sci. PD SEP PY 1998 VL 63 IS 2 BP 453 EP 457 PG 5 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 161BV UT WOS:000078268900015 ER PT J AU Aronson, RB Precht, WF Macintyre, IG AF Aronson, RB Precht, WF Macintyre, IG TI Extrinsic control of species replacement on a Holocene reef in Belize: the role of coral disease SO CORAL REEFS LA English DT Article DE Acropora; carbonate sedimentology; community structure; coral reef; disease; succession ID DISTURBANCE; COMMUNITIES; STABILITY; ECOLOGY; FACIES AB Well-preserved, Holocene coral reefs provide the opportunity to discriminate between models of intrinsically driven succession and extrinsically driven species replacement, especially when paleontological patterns can be combined with ecological observations of the underlying mechanisms. Rhomboid shoals in the central shelf lagoon of the Belizean Barrier Reef experienced a recent and dramatic change in community composition. Agaricia tenuifolia replaced Acropora cervicornis as the dominant coral species at 3-15 m depth along the flanks of the reefs. We tested the hypothesis that shallowing upward caused this shift in dominance. A core extracted from 0.5 m water depth on one of the shoals, Channel Gay, revealed a shallowing-upward shift in dominance from Acropora to Porites divaricata. This successional sequence was quite different from the Acropora-to-Agaricia transition observed in four cores from 6-11 m water depth. Ecological observations showed that Agaricin became the dominant at greater than or equal to 3 m depth after Acropora populations were decimated by a regional outbreak of white-band disease. The Acropora-to-Agaricia transition was clearly a case of extrinsically driven species replacement rather than an intrinsically driven, successional, shallowing-upward sequence. C1 Dauphin Isl Sea Lab, Dauphin Island, AL 36528 USA. Univ S Alabama, Dept Marine Sci, Mobile, AL 36688 USA. Law Engn & Environm Serv Inc, Miami Lakes, FL 33014 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. RP Aronson, RB (reprint author), Dauphin Isl Sea Lab, POB 369, Dauphin Island, AL 36528 USA. NR 50 TC 76 Z9 82 U1 0 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD SEP PY 1998 VL 17 IS 3 BP 223 EP 230 DI 10.1007/s003380050122 PG 8 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 128FD UT WOS:000076394300005 ER PT J AU Greenstein, BJ Curran, HA Pandolfi, JM AF Greenstein, BJ Curran, HA Pandolfi, JM TI Shifting ecological baselines and the demise of Acropora cervicornis in the western North Atlantic and Caribbean Province: a Pleistocene perspective SO CORAL REEFS LA English DT Article DE Acropora cervicornis; shifting baseline syndrome; Pleistocene fossil coral reef assemblages ID GREAT-BARRIER-REEF; BLACK BAND DISEASE; CORAL-REEFS; COMMUNITY STRUCTURE; MASS MORTALITY; DIADEMA-ANTILLARUM; PHASE-SHIFTS; DISTURBANCE; HURRICANES; CONSTANCY AB In recent years, marine scientists have become increasingly alarmed over the decline of live coral cover throughout the Caribbean and tropical western Atlantic region. The Holocene and Pleistocene fossil record of coral reefs from this region potentially provides a wealth of long-term ecologic information with which to assess the historical record of changes in shallow water coral reef communities. Before fossil data can be applied to the modern reef system, critical problems involving fossil preservation must be addressed. Moreover, it must be demonstrated that the classic reef coral zonation patterns described in the early days of coral reef ecology, and upon which "healthy" versus "unhealthy" reefs are determined, are themselves representative of reefs that existed prior to any human influence. To address these issues, we have conducted systematic censuses of life and death assemblages on modern "healthy" patch reefs in the Florida reef tract that conform to the classic Caribbean model of reef coral zonation, and a patch reef in the Bahamas that is currently undergoing a transition in coral dominance that is part of a greater Caribbean-wide phenomenon. Results were compared to censuses of ancient reef assemblages preserved in Pleistocene limestones in close proximity to each modern reef. We have determined that the Pleistocene fossil record of coral reefs may be used to calibrate an ecological baseline with which to compare modern reef assemblages, and suggest that the current and rapid decline of Acropora cervicornis observed on a Bahamian patch reef may be a unique event that contrasts with the long-term persistence of this taxon during Pleistocene and Holocene time. C1 Cornell Coll, Dept Geol, Mt Vernon, IA 52314 USA. Smith Coll, Dept Geol, Northampton, MA 01063 USA. Smithsonian Inst, Museum Natl Hist Nat, Dept Paleobiol, Washington, DC 20560 USA. RP Greenstein, BJ (reprint author), Cornell Coll, Dept Geol, 600 1st St W, Mt Vernon, IA 52314 USA. RI Pandolfi, John/A-3121-2009 OI Pandolfi, John/0000-0003-3047-6694 NR 72 TC 75 Z9 84 U1 5 U2 24 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD SEP PY 1998 VL 17 IS 3 BP 249 EP 261 DI 10.1007/s003380050125 PG 13 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 128FD UT WOS:000076394300008 ER PT J AU Chance, K AF Chance, K TI Analysis of BrO measurements from the Global Ozone Monitoring Experiment SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID BROMINE; RELEASE AB The Global Ozone Monitoring Experiment (GOME), launched on the ESA ERS-2 satellite in April 1995, measures solar back scatter spectra from which atmospheric BrO columns may be derived globally with high precision (slant column uncertainties of +/-3x10(13) cm(-2) or less). Obtaining such precision requires additional characterization of GOME spectra, reference spectra that are well calibrated in wavelength, and a fitting method capable of reproducing measurements to several parts in 10(4). This paper describes these elements of the data processing and gives examples of BrO distributions in the stratosphere and enhanced tropospheric BrO in the polar springtime. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Chance, K (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Chance, Kelly/0000-0002-7339-7577 NR 12 TC 114 Z9 114 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD SEP 1 PY 1998 VL 25 IS 17 BP 3335 EP 3338 DI 10.1029/98GL52359 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 116TC UT WOS:000075739800033 ER PT J AU Buckley, PA Francis, CM Blancher, P DeSante, DF Robbins, CS Smith, G Cannell, P AF Buckley, PA Francis, CM Blancher, P DeSante, DF Robbins, CS Smith, G Cannell, P TI The North American Bird Banding Program: Into the 21st century SO JOURNAL OF FIELD ORNITHOLOGY LA English DT Article AB The authors examined the legal, scientific, and philosophical underpinnings of the North American Bird Banding Program [BBP], with emphasis on the U.S. Bird Banding Laboratory [BBL], but also considering the Canadian Bird Banding Office [BBO]. In this report, we review the value of banding data, enumerate and expand on the principles under which any modern BBP should operate, and from them derive our recommendations. These are cast into a Mission Statement, a Role and Function Statement, and a series of specific recommendations addressing five areas: (1) permitting procedures and practices; (2) operational issues; (3) data management; (4) BBL organization and staffing; and (5) implementation. Our major tenets and recommendations are as follows: banding provides valuable data for numerous scientific, management, and educational purposes, and its benefits far outweigh necessary biological and fiscal costs, especially those incurred by the BBL and BBO; because of the value of banding data for management of avian resources, including both game and nongame birds, government supper; of the program is fully justified and appropriate; all banding data, if collected to appropriate standards, are potentially valuable; there are many ways to increase the value of banding data such as by endorsing, promoting, and applying competence and/or training standards for permit issuance; promoting bander participation in well-designed projects; and by encouraging the use of banding data for meta-analytical approaches; the BBL should apply, promote, and encourage such standards, participation, and approaches; the BBP should be driven by the needs of users, including scientists and managers; all exchange of data and most communication between banders and the BBL should become electronic in the near future; the computer system at the BBL should be modernized to one designed for a true client-server relationship and storage of data in on-line relational databases; the BBL should continue to maintain high quality control and editing standards and should strive to bring all data in the database up to current standards; however, the BBL should transfer a major portion of the responsibility for editing banding data to the bander by providing software that will permit the bander to edit his/her own data electronically before submission to the BBL; the BBL should build the capacity to store additional data tied to original band records able to be pre-edited and submitted electronically, such as recapture data, appropriate data from auxiliary marking (e.g., resightings of color-marked birds), and other data that gain value when pooled from many banders (e.g., measurements); however, the BBL should only accept such data if they are collected using standardized methods and as part of an established program designed to utilize such data; now is the time to consider options for implementing a Western Hemisphere banding program, with leadership from the BBL; the Patuxent Electronic Data Processing Section should become part of the BBL; additional scientific and technical staff must be added to the BBL; an Implementation Team should be formed to expedite our recommendations, following timetables outlined in this document. C1 Univ Rhode Isl, Grad Sch Oceanog, USGS, Patuxent Wildlife Res Ctr, Narragansett, RI 02882 USA. Long Point Bird Observ, Port Rowan, ON N0E 1M0, Canada. Canadian Wildlife Serv, Natl Wildlife Res Ctr, Hull, PQ K1A 0H3, Canada. Inst Bird Populat, Pt Reyes Stn, CA 94956 USA. USGS, Patuxent Wildlife Res Ctr, Laurel, MD 20708 USA. US Fish & Wildlife Serv, Patuxent Wildlife Res Ctr, Henshaw Lab, Laurel, MD 20708 USA. Smithsonian Inst Press, Washington, DC 20560 USA. RP Buckley, PA (reprint author), Univ Rhode Isl, Grad Sch Oceanog, USGS, Patuxent Wildlife Res Ctr, Box 8, Narragansett, RI 02882 USA. NR 1 TC 10 Z9 10 U1 2 U2 11 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 FAL PY 1998 VL 69 IS 4 BP 511 EP 529 PG 19 WC Ornithology SC Zoology GA 151YU UT WOS:000077748900001 ER PT J AU Rappole, JH Winker, K Powell, GVN AF Rappole, JH Winker, K Powell, GVN TI Migratory bird habitat use in southern Mexico: Mist nets versus point counts SO JOURNAL OF FIELD ORNITHOLOGY LA English DT Article ID POPULATIONS; DENSITY; RATES AB Most previous studies of habitat use by migratory birds in the tropics have used either mist nets or point counts to assess relative densities of migrants among habitats. We used both methods on the same 30 sites in southern Veracruz: 10 sites in forest (canopy >10 m), 10 sites in second growth (canopy 3-10 m), and 10 sites in the open (canopy <3 m). Results demonstrate that either method used alone is likely to underestimate or miss whole categories of species. Three aerial or canopy-foraging species found on point counts were missed by mist netting, while several others in these categories were under-represented in mist net samples, especially in forest habitats. Nine species represented in mist net samples were not recorded in point counts, probably because of low density and/or secretive habits. The strengths of one method tend to offset the weaknesses of the other, and we propose a methodology that combines both procedures to provide a more accurate assessment of avian habitat use. C1 Smithsonian Inst, Conservat & Res Ctr, Natl Zool Pk, Front Royal, VA 22630 USA. Univ Alaska Museum, Fairbanks, AK 99775 USA. RARE, San Jose 1000, Costa Rica. RP Rappole, JH (reprint author), Smithsonian Inst, Conservat & Res Ctr, Natl Zool Pk, Front Royal, VA 22630 USA. RI Winker, Kevin/M-2042-2014 OI Winker, Kevin/0000-0002-8985-8104 NR 16 TC 44 Z9 50 U1 1 U2 12 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 FAL PY 1998 VL 69 IS 4 BP 635 EP 643 PG 9 WC Ornithology SC Zoology GA 151YU UT WOS:000077748900014 ER PT J AU Galera, V Ubelaker, DH Hayek, LC AF Galera, V Ubelaker, DH Hayek, LC TI Comparison of macroscopic cranial methods of age estimation applied to skeletons from the Terry Collection SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; forensic anthropology; physical anthropology; Terry Collection; cranial age estimation; macroscopic methods ID DEATH AB A total of 963 skeletons (408 Whites and 555 Blacks) from the Terry Collection were studied to examine macroscopic cranial methods of age estimation. The methods of Acsidi and Nemeskeri, Masser, Baker and Meindl and Lovejoy were applied to every skull. The results indicate that the most accurate techniques in this application were those that consider endocranial suture closure. The methods of Acsidi and Nemeskeri and Masset were the most accurate in all the subsamples (by population, sex, sex within population and in total), although the relative accuracy could vary in application to other populations. C1 Univ Alcala de Henares, Fac Sci, Dept Anthropol, E-28871 Alcala De Henares, Spain. Natl Museum Nat Hist, Dept Anthropol, Smithsonian Inst, Washington, DC 20560 USA. RP Galera, V (reprint author), Univ Alcala de Henares, Dept Biol Anim, E-28871 Alcala De Henares, Spain. NR 20 TC 31 Z9 33 U1 0 U2 9 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD SEP PY 1998 VL 43 IS 5 BP 933 EP 939 PG 7 WC Medicine, Legal SC Legal Medicine GA 113UW UT WOS:000075572900001 PM 9729807 ER PT J AU Lounibos, LP Wilkerson, RC Conn, JE Hribar, LJ Fritz, GN Danoff-Burg, JA AF Lounibos, LP Wilkerson, RC Conn, JE Hribar, LJ Fritz, GN Danoff-Burg, JA TI Morphological, molecular, and chromosomal discrimination of cryptic Anopheles (Nyssorhynchus) (Diptera : Culicidae) from South America SO JOURNAL OF MEDICAL ENTOMOLOGY LA English DT Article DE accessory glands; chromosomes; DNA; egg morphology; isomorphic species; isoenzymes ID POLYMERASE CHAIN-REACTION; RIBOSOMAL DNA; NUNEZTOVARI DIPTERA; POPULATIONS AB Based on similarity of male genitalia, the malaria vector Anopheles trinkae Faran from the eastern Andean piedmont of Colombia, Ecuador, Peru, and Bolivia was determined by Peyton (1993) to be a junior synonym of An. dunhami Causey, then known from a single locality ill Amazonian Brazil. Following an appraisal of molecular, chromosomal, and. morphological characters, we conclude herein that the 2 taxa are specifically distinct and remove An. trinkae from synonymy with An. dunhami. Eggs of the 2 species are distinguished easily by the anterior crown, long floats, and closed deck that occur only in An. trinkae. The X chromosome of larval polytenes is divisible into R and L arms in An. dunhami, but not in An. trinkae. A phenogram based an banding pattern scores from 18 random amplified polymorphic DNA primers separated with 100% resolution An. dunhami, An. trinkae, Anopheles nuneztovari Gabaldon and Anopheles darlingi Root. In the ITS2 region of rDNA, 25% of base sites distinguished An. trinkae from An. dunhami and 21% from the related An. nuneztovari; males of these 3 species had accessory glands of significantly different sizes. Preliminary isoenzyme screening indicated that 3 of 11 loci were diagnostic for separating An. trinkae from An. dunhami. The results indicate that An. dunhami is related more closely to An. nuneztovari than to An. trinkae and illustrate the merits of a multidisciplinary approach to mosquito systematics. C1 Univ Florida, Florida Med Entomol Lab, Vero Beach, FL 32962 USA. Smithsonian Inst, Museum Support Ctr, Walter Reed Biosystemat Unit, Washington, DC 20560 USA. Univ Vermont, Dept Biol, Burlington, VT 05405 USA. Eastern Illinois Univ, Dept Zool, Charleston, IL 61920 USA. Amer Museum Nat Hist, Dept Entomol, New York, NY 10024 USA. RP Lounibos, LP (reprint author), Univ Florida, Florida Med Entomol Lab, 200 9th St SE, Vero Beach, FL 32962 USA. OI Danoff-Burg, James/0000-0002-0685-6948; Conn, Jan/0000-0002-5301-7020 FU NIAID NIH HHS [AI-40116, AI-31034] NR 41 TC 30 Z9 31 U1 0 U2 0 PU ENTOMOL SOC AMER PI LANHAM PA 9301 ANNAPOLIS RD, LANHAM, MD 20706 USA SN 0022-2585 J9 J MED ENTOMOL JI J. Med. Entomol. PD SEP PY 1998 VL 35 IS 5 BP 830 EP 838 PG 9 WC Entomology; Veterinary Sciences SC Entomology; Veterinary Sciences GA 124YN UT WOS:000076210500036 PM 9775617 ER PT J AU Parenti, LR Thomas, KR AF Parenti, LR Thomas, KR TI Pharyngeal jaw morphology and homology in sicydiine gobies (Teleostei : Gobiidae) and allies SO JOURNAL OF MORPHOLOGY LA English DT Article DE sicydiine gobies; pharyngeal jaws; pharyngeal teeth ID GOBIOID FISHES; SYSTEMATICS; OSTEOLOGY; APPARATUS; ONTOGENY; TOOTH AB An extremely large number of fifth ceratobranchial teeth, with highly modified, striated, and hooked tips were observed in the central and western Pacific sicydiine goby genus Stiphodon. A scanning electron microscopic study of the form and arrangement of fifth ceratobranchial teeth was conducted to assess the distribution of these modifications in sicydiine gobies and their putative close relatives. Our goals were to explore a new set of characters in gobioid systematics, to test sicydiine monophyly, and to test hypotheses of relationships of sicydiine gobies. Sicydiines are hypothesized herein to be most closely related to the western Pacific Tukugobius and Rhinogobius, freshwater genera with which they share thickened pelvic-fin rays, no teeth on the anterior portion of the fifth ceratobranchial bones, fifth ceratobranchial teeth with differentiated and striated tips, and overlapping anterior rami of the fifth ceratobranchial bones. The latter two characters occur in some, but not all, sicydiines. The pantropical freshwater goby Awaous, often classified with sicydiines, is not considered the closest relative of the subfamily. The highly modified fifth ceratobranchials of Stiphodon are similar to, and concluded here to be homoplasious with, those of the mudflat-dwelling New World goby Evorthodus and the Indo-west Pacific oxudercine gobies, represented in this study by Pseudapocryptes. (C) 1998 Wiley-Liss, Inc.(dagger). C1 Smithsonian Inst, Natl Museum Nat Hist, Div Fishes, Washington, DC 20560 USA. Samford Univ, Dept Biol, Birmingham, AL USA. RP Parenti, LR (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Div Fishes, Washington, DC 20560 USA. EM parenti.lynne@nmnh.si.edu NR 39 TC 31 Z9 32 U1 0 U2 9 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0362-2525 J9 J MORPHOL JI J. Morphol. PD SEP PY 1998 VL 237 IS 3 BP 257 EP 274 PG 18 WC Anatomy & Morphology SC Anatomy & Morphology GA 114RR UT WOS:000075623100004 ER PT J AU Oliver, WA AF Oliver, WA TI Nomenclatural problems of Breviphrentis Stumm, 1949 and Contophrentis new genus (Devonian rugose corals) SO JOURNAL OF PALEONTOLOGY LA English DT Article C1 Smithsonian Inst, US Geol Survey, Washington, DC 20560 USA. Smithsonian Inst, Museum Natl Hist Nat, Dept Paleobiol, Washington, DC 20560 USA. RP Oliver, WA (reprint author), Smithsonian Inst, US Geol Survey, MRC 137, Washington, DC 20560 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 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 SEP PY 1998 VL 72 IS 5 BP 932 EP 934 PG 3 WC Paleontology SC Paleontology GA 121AD UT WOS:000075989200011 ER PT J AU Early, E Thompson, A Johnson, C DeLuisi, J Disterhoft, P Wardle, D Wu, E Mou, WF Ehramjian, J Tusson, J Mestechkina, T Beaubian, M Gibson, J Hayes, D AF Early, E Thompson, A Johnson, C DeLuisi, J Disterhoft, P Wardle, D Wu, E Mou, WF Ehramjian, J Tusson, J Mestechkina, T Beaubian, M Gibson, J Hayes, D TI The 1996 North American Interagency Intercomparison of Ultraviolet Monitoring Spectroradiometers SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE environmental monitoring; intercomparison; solar ultraviolet; spectroradiometers ID MERCURY PENCIL LAMPS; STANDARD LAMPS; SPECTRAL-LINES AB Concern over stratospheric ozone depletion has prompted several government agencies in North America to establish networks of spectroradiometers for monitoring solar ultraviolet irradiance at the surface of the Earth. To assess the ability of spectroradiometers to accurately measure solar ultraviolet irradiance, and to compare the results between instruments of different monitoring networks, the third North American Interagency Intercomparison of Ultraviolet Monitoring Spectroradiometers was held June 17-25, 1996 at Table Mountain outside Boulder, Colorado, USA. This Intercomparison was coordinated by the National Institute of Standards and Technology (NIST) and the National Oceanic and Atmospheric Administration (NOAA). Participating agencies were the Environmental Protection Agency; the National Science Foundation; the Smithsonian Environmental Research Center; the Department of Agriculture; and the Atmospheric Environment Service, Canada. The spectral irradiances of participants' calibrated standard lamps were measured at NIST prior to the Intercomparison. The spectral irradiance scales used by the participants agreed with the NIST scale within the combined uncertainties, and for all lamps the spectral irradiance in the horizontal position was lower than that in the vertical position. Instruments were characterized for wavelength uncertainty, bandwidth, stray-light rejection, and spectral irradiance responsivity, the latter with NIST standard lamps operating in specially designed field calibration units. The spectral irradiance responsivity demonstrated instabilities for some instruments. Synchronized spectral scans of the solar irradiance were performed over several days. Using the spectral irradiance responsivities determined with the NIST standard lamps, the measured solar irradiances had some unexplained systematic differences between instruments. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NOAA, R E ARX1, Boulder, CO 80303 USA. Environm Canada, Atomospher Environm Serv, Toronto, ON M3H 5T4, Canada. Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. Biospher Inc, San Diego, CA 92110 USA. Yankee Environm Syst Inc, Turners Falls, MA 01376 USA. Colorado State Univ, USDA, UV B Radiat Monitoring Program, Nat Resource Ecol Lab, Ft Collins, CO USA. Smithsonian Inst, Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Early, E (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 9 TC 8 Z9 8 U1 0 U2 1 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD SEP-OCT PY 1998 VL 103 IS 5 BP 449 EP 482 DI 10.6028/jres.103.028 PG 34 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 143JZ UT WOS:000077253200001 PM 28009358 ER PT J AU Reid, RP MacIntyre, IG AF Reid, RP MacIntyre, IG TI Carbonate recrystallization in shallow marine environments: A widespread diagenetic process forming micritized grains SO JOURNAL OF SEDIMENTARY RESEARCH LA English DT Article ID MAGNESIAN CALCITE; NANNOBACTERIA; BACTERIA; SEDIMENTS; DISSOLUTION; CHEMISTRY; CEMENT; WATER; SEM AB Integrated morphologic, petrographic, and mineralogic analyses of sediment grains of the miliolid foraminifer Archaias and the green alga Halimeda from shallow marine environments in Florida, the Bahamas, and Belize document pervasive syndepositional recrystallization in these grains. Scanning electron microscopy shows that original skeletal rods and needles recrystallize on the sea floor to a variety of equant micritic fabrics. In thin section, this textural alteration corresponds to progressive micritization, with loss of the familiar golden brown color exhibited by fresh miliolids and Halimeda and gradual development of gray cryptocrystalline carbonate. X-ray diffraction and electron microprobe studies show that this textural alteration may be accompanied by mineralogical changes from Mg-calcite to aragonite or from aragonite to Mg-calcite. Our findings support petrographic studies that reported syndepositional recrystallization in a wide variety of carbonate grains about thirty years ago, but which have been largely ignored. Together, these studies indicate that carbonate recrystallization is a widespread process of early diagenesis, Extensive recrystallization in shallow tropical seas challenges basic principles regarding the setting and timing of textural and mineralogic alteration of metastable carbonate grains. In addition, recognition of recrystallization as an important process of micritization contradicts prevailing theories that micritization results solely by infilling of microborings. Finally, our findings raise fundamental questions concerning the nature of carbonate crystal structure, mechanisms of crystal growth, and driving forces for recrystallization, Answering these questions will require sedimentologists to step beyond traditional bounds into fields such as biomineralization and materials science. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. RP Reid, RP (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. NR 54 TC 77 Z9 82 U1 1 U2 9 PU SEPM-SOC SEDIMENTARY GEOLOGY PI TULSA PA 1731 E 71ST STREET, TULSA, OK 74136-5108 USA SN 1073-130X J9 J SEDIMENT RES JI J. Sediment. Res. PD SEP PY 1998 VL 68 IS 5 BP 928 EP 946 PN A PG 19 WC Geology SC Geology GA 125JC UT WOS:000076233600022 ER PT J AU Heald, S Ash-Milby, KE AF Heald, S Ash-Milby, KE TI Woven by the grandmothers: Twenty-Four blankets travel to the Navajo nation SO JOURNAL OF THE AMERICAN INSTITUTE FOR CONSERVATION LA English DT Article; Proceedings Paper CT General Session on Collaboration in the Visual Arts, at the American-Institute-for-Conservation 24th Annual Meeting CY JUN 10-16, 1996 CL NORFOLK, VIRGINIA SP Amer Inst Conservat C1 Smithsonian Inst, Natl Museum Amer Indian, Dept Conservat, Suitland, MD 20746 USA. RP Heald, S (reprint author), Smithsonian Inst, Natl Museum Amer Indian, Dept Conservat, Suitland, MD 20746 USA. NR 10 TC 1 Z9 1 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 FAL-WIN PY 1998 VL 37 IS 3 BP 334 EP 345 DI 10.2307/3179817 PG 12 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA 180GT UT WOS:000079378300006 ER PT J AU Fraver, S Brokaw, NVL Smith, AP AF Fraver, S Brokaw, NVL Smith, AP TI Delimiting the gap phase in the growth cycle of a Panamanian forest SO JOURNAL OF TROPICAL ECOLOGY LA English DT Article DE average daily global radiation; Desmopsis; gap phase regeneration; Panama; Protium; Tetragastris; treefall gap; tropical forest ID TROPICAL MOIST FOREST; RAIN-FOREST; TREEFALL GAPS; CANOPY GAPS; NEOTROPICAL FOREST; SEEDLING GROWTH; SURVIVAL; DEFINITION; LIGHT; ENVIRONMENTS AB Despite the importance of treefall gaps in tropical forest dynamics, few studies have followed gap-phase processes for more than 2 y. We monitored, for five years, the growth and survival of many seedlings of Tetragastris panamensis (Engler) O. Kuntze, Protium panamense (Rose) I. M. Johnston, and Desmopsis panamensis (Rob.) Saff. (three common tree species of the Panamanian tropical moist forest) in artificially created treefall gaps and under intact-canopy control plots. On these same plots, we also monitored light levels using hemispherical photographs taken over an 8-y period. Seedling height growth was faster in gaps than under intact canopies during the first 42 mo of regrowth, then declined to rates similar to those under intact canopies. Light levels in gaps similarly rose and fell, returning to pre-gap levels by month 48. Only Tetragastris panamensis showed higher survival in gaps, contrary to the general assumption that seedling survival is enhanced by gap creation. Our results document important transition points that mark the conclusion of the gap phase, suggesting an estimate of dry for the duration of the gap phase in this tropical forest. C1 N Carolina State Univ, Dept Forestry, Raleigh, NC 27695 USA. Manomet Ctr Conservat Sci, Manomet, MA 02345 USA. Smithsonian Trop Res Inst, Balboa, Panama. Univ Miami, Dept Biol, Coral Gables, FL 33124 USA. RP Fraver, S (reprint author), N Carolina State Univ, Dept Forestry, Box 8002, Raleigh, NC 27695 USA. NR 40 TC 22 Z9 27 U1 1 U2 6 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0266-4674 J9 J TROP ECOL JI J. Trop. Ecol. PD SEP PY 1998 VL 14 BP 673 EP 681 DI 10.1017/S0266467498000479 PN 5 PG 9 WC Ecology SC Environmental Sciences & Ecology GA 139GQ UT WOS:000077020100008 ER PT J AU Dalling, JW Wirth, R AF Dalling, JW Wirth, R TI Dispersal of Miconia argentea seeds by the leaf-cutting ant Atta colombica SO JOURNAL OF TROPICAL ECOLOGY LA English DT Article DE Atta colombica; leaf-cutter ant; Miconia argentea; seed dispersal; seed germination ID PIONEER TREE; RAIN-FOREST; REGENERATION; PREDATORS; SELECTION C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Kaiserslautern, Fachbereich Biol, Abt Allgemeine Bot, D-67663 Kaiserslautern, Germany. RP Dalling, JW (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. RI Wirth, Rainer/I-1552-2013 OI Wirth, Rainer/0000-0001-8042-3123 NR 19 TC 29 Z9 30 U1 1 U2 10 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0266-4674 J9 J TROP ECOL JI J. Trop. Ecol. PD SEP PY 1998 VL 14 BP 705 EP 710 DI 10.1017/S0266467498000492 PN 5 PG 6 WC Ecology SC Environmental Sciences & Ecology GA 139GQ UT WOS:000077020100010 ER PT J AU Steppan, SJ Pardinas, UFJ AF Steppan, SJ Pardinas, UFJ TI Two new fossil muroids (Sigmodontinae : Phyllotini) from the early Pleistocene of Argentina: Phylogeny and paleoecology SO JOURNAL OF VERTEBRATE PALEONTOLOGY LA English DT Article ID CRICETIDAE; RODENTIA AB Two new species and genera of extinct muroid rodents are described from fossil material dating to the early Pleistocene of Argentina (Sanandresian Substage/Subage). They are both tetralophodont forms belonging to the tribe Phyllotini (Sigmodontinae) and are assigned to Ichthyurodon ameghinoi, gen, et sp. nov., and Olympicomys vossi, gen. et sp. nov. Phylogenetic analyses involving extant phyllotines, the two new species, and two other newly discovered extinct phyllotines result in a refined and expanded concept of the clade consisting of Loxodontomys and the Reithrodon generic group. The generic diversity of this clade is thus doubled from four to eight. Several of the fossil genera appear to represent transitional forms, although Ichthyurodon, gen. nov., possesses dental traits unique among the members of the subfamily Sigmodontinae. The significance of the new species and their faunal context For our understanding of the paleoecology of the southern cone of South America is discussed. C1 Smithsonian Inst, Div Mammals, Washington, DC 20560 USA. Smithsonian Inst, Lab Mol Systemat, Washington, DC 20560 USA. Museo La Plata, Dept Cient Paleontol Vertebrados, RA-1900 La Plata, Argentina. RP Steppan, SJ (reprint author), Smithsonian Inst, Div Mammals, MRC 534, Washington, DC 20560 USA. NR 51 TC 13 Z9 15 U1 0 U2 0 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 SEP PY 1998 VL 18 IS 3 BP 640 EP 649 PG 10 WC Paleontology SC Paleontology GA 122HE UT WOS:000076065400018 ER PT J AU Shrestha, SP Ullrey, DE Bernard, JB Wemmer, C Kraemer, DC AF Shrestha, SP Ullrey, DE Bernard, JB Wemmer, C Kraemer, DC TI Plasma vitamin E and other analyte levels in nepalese camp elephants (Elephas maximus) SO JOURNAL OF ZOO AND WILDLIFE MEDICINE LA English DT Article DE Asian elephant; Elephas maximus; alpha-tocopherol; retinol; Nepal ID PERFORMANCE LIQUID-CHROMATOGRAPHY; SERUM BIOCHEMISTRY VALUES; TISSUE ALPHA-TOCOPHEROL; SRI-LANKA; SELENIUM; RETINOL; SUPPLEMENTATION; HEMATOLOGY; CEYLONICUS; PERIOD AB Plasma concentrations of alpha-tocopherol (vitamin E) and other analytes in Asian elephants (Elephas maximus) in Nepal were determined during typical work camp management of the elephants. Elephants foraged for food for 4-6 hr each day under the control of mahouts and were also provided daily with cut forage and supplements of unhusked rice, cane molasses, and salt. Blood samples were taken monthly for 1 yr without chemical restraint from 26 female elephants in four camps. Elephants were 6-60+ yr of age. Mean (+/-SEM) alpha-tocopherol concentration was 0.77 +/- 0.047 mu g/ml, with a range of 0.23-1.57 mu g/ml. Subadults had lower concentrations than did older elephants, and there were significant differences in mean concentrations from different camps and in mean monthly concentrations. Plasma alpha-tocopherol concentration appears to vary widely between individuals, and a single value of <0.3 mu g/ml is not sufficient to diagnose incipient vitamin E deficiency. Mean (+/-SEM) plasma retinol (vitamin A) concentration was 0.063 +/- 0.003 mu g/ml with a range of 0.01-0.12 mu g/ml. Subadults had higher concentrations than did older elephants, and mean retinal values differed significantly among camps. Beta-carotene was not found in plasma. Twenty-five other analytes determined or derived were generally similar to those reported in other Asian and African (Loxodonta africana) elephants. Estimates of nutrient intake, based upon diet composition, suggested that dietary concentrations of zinc and sodium may have been marginal, but the absence of signs of any nutrient deficiencies Indicates that dietary husbandry in these elephant camps was generally satisfactory. C1 Texas A&M Univ, Dept Vet Physiol, College Stn, TX 77843 USA. Michigan State Univ, Dept Anim Sci, Comparat Nutr Grp, E Lansing, MI 48824 USA. Smithsonian Inst, Natl Zool Pk Conservat & Res Ctr, Front Royal, VA 22630 USA. RP Shrestha, SP (reprint author), Univ Florida, Div Comparat Med, Box 100006, Gainesville, FL 32610 USA. NR 54 TC 4 Z9 5 U1 0 U2 3 PU AMER ASSOC Z00 VETERINARIANS PI MEDIA PA 6 NORTH PENNELL ROAD, MEDIA, PA 19063 USA SN 1042-7260 J9 J ZOO WILDLIFE MED JI J. Zoo Wildl. Med. PD SEP PY 1998 VL 29 IS 3 BP 269 EP 278 PG 10 WC Veterinary Sciences SC Veterinary Sciences GA 129VQ UT WOS:000076485100002 PM 9809597 ER PT J AU Cohen, AC Martin, JW Kornicker, LS AF Cohen, AC Martin, JW Kornicker, LS TI Homology of Holocene ostracode biramous appendages with those of other crustaceans: the protopod, epipod, exopod and endopod SO LETHAIA LA English DT Article DE Ostracoda; Myodocopa; crustacea; Podocopa; homology; morphology ID MYODOCOPID OSTRACODES; JAPAN; MORPHOLOGY; PHYLOGENY; POSITION; BEARING; ORIGIN AB Unambiguously biramous appendages with a proximal precoxa, well-defined coxa and basis, setose plate-like epipod originating on the precoxa, and both an endopod and exopod attached to the terminal end of the basis are described from several living Ostracoda of the order Halocyprida (Myodocopa). These limbs are proposed as the best choice for comparison of ostracode limbs with those of other crustaceans and fossil arthropods with preserved limbs, such as the Cambrian superficially ostracode-like Kunmingella and Hesslandona. The 2nd maxilla of Metapolycope (Cladocopina) and 1st trunk limb of Spelaeoecia, Deeveya and Thaumatoconcha (all Halocypridina) are illustrated, and clear homologies are shown between the parts of these limbs and those of some general crustacean models as well as some of the remarkable crustacean s.s. Orsten fossils. No living ostracodes exhibit only primitive morphology; all have at least some (usually many) derived characters. Few have the probably primitive attribute of trunk segmentation (two genera of halocyprid Myodocopa, one order plus one genus of Podocopa, and the problematic Manawa); unambiguously biramous limbs are limited to a few halocyprids. Homologies between podocopid limbs and those of the illustrated primitive myodocopid limbs are tentatively suggested. A setose plate like extension, often attached basally to a podocopid protopod, is probably homologous to the myodocopid epipod, which was present at least as early as the Triassic. Somewhat more distal, less setose, and plate-like extensions, present on some podocopid limbs (e.g., mandible), may be homologous instead to the exopod (clearly present on myodocopid mandibles). The coxa (or precoxa) is by definition the most basal part of the limb. A molar-like tooth is present proximally on the mandibular protopod of many ostracodes; it is the coral endite and projects medially from the coxa (or proximal protopod). The Ostracoda is probably a monophyletic crustacean group composed of Myodocopa and Podocopa. All have a unique juvenile (not a larva) initially with three or more limbs. Except that juveniles lack some setae and limbs, they are morphologially similar to the adult. Thus the following suite of characters in all instars may be considered a synapomorphy uniting all Ostracoda: (1) Each pair of limbs is uniquely different from the others. (2) The whole body is completely enclosed within a bivalved carapace that lacks growth lines. (3) No more than nine pairs of limbs are present in any instar. (4) The body shows little or no segmentation, with no more than ten dorsally defined trunk segments. No other crustaceans have this suite of characters. A probable synapomorphy uniting the Podocopa is a 2nd antenna with exopod reduced relative to the endopod. C1 Univ Calif Davis, Bodega Marine Lab, Bodega Bay, CA 94923 USA. Natl Hist Museum Los Angeles Cty, Res & Collect, Los Angeles, CA 90007 USA. Natl Museum Nat Hist, Dept Invertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. RP Cohen, AC (reprint author), Univ Calif Davis, Bodega Marine Lab, POB 247, Bodega Bay, CA 94923 USA. NR 80 TC 20 Z9 23 U1 0 U2 4 PU SCANDINAVIAN UNIVERSITY PRESS PI OSLO PA PO BOX 2959 TOYEN, JOURNAL DIVISION CUSTOMER SERVICE, N-0608 OSLO, NORWAY SN 0024-1164 J9 LETHAIA JI Lethaia PD SEP PY 1998 VL 31 IS 3 BP 251 EP 265 PG 15 WC Paleontology SC Paleontology GA 126QP UT WOS:000076304900010 ER PT J AU Symmes, M AF Symmes, M TI Drawings for the great fountains of Rome and Paris SO MAGAZINE ANTIQUES LA English DT Article C1 Smithsonian Inst, Cooper Hewitt Natl Design Museum, Drue Heinz Study Ctr Drawings & Prints, New York, NY USA. RP Symmes, M (reprint author), Smithsonian Inst, Cooper Hewitt Natl Design Museum, Drue Heinz Study Ctr Drawings & Prints, New York, NY USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU BRANT PUBL, INC PI NEW YORK PA 575 BROADWAY, NEW YORK, NY 10012 USA SN 0161-9284 J9 MAG ANTIQUES JI Mag. Antiq. PD SEP PY 1998 VL 154 IS 3 BP 346 EP 355 PG 10 WC Art SC Art GA 115HC UT WOS:000075657200018 ER PT J AU Thiel, M AF Thiel, M TI Population biology of Dyopedos monacanthus (Crustacea : Amphipoda) on estuarine soft-bottoms: importance of extended parental care and pelagic movements SO MARINE BIOLOGY LA English DT Article ID COROPHIUM-VOLUTATOR PALLAS; LIFE-HISTORY PATTERNS; GAMMARIDEAN AMPHIPOD; REPRODUCTIVE-BIOLOGY; CAPRELLID AMPHIPODS; SELECTIVE PREDATION; MATERNAL-CARE; ST-LAWRENCE; SHELF; COMMUNITY AB The suspension-feeding amphipod Dyopedos monacanthus (Metzger, 1875) is a common epibenthic amphipod that lives on self-constructed "mud whips" (built from filamentous algae, detritus and sediment particles) in estuaries of the northern North Atlantic Ocean. The population biology of D. monacanthus at a shallow subtidal site in the Damariscotta River Estuary (Maine, USA) was examined between July 1995 and July 1997. The resident population at the study site was dominated by adult females during most months of the year. High percentages of subadults were found in late summer/early fall. Often, between 10 and 20% of the adult females were paired with males, and the percentage of ovigerous females varied between 40 and 100%, indicating continuous reproduction. The percentage of parental females varied between 40 and 80% during most months, but dropped to levels below 20% during summer:early fall. The average size of amphipods on their own mud whips was similar to 4 mm during the summer/ early fall, after which it increased continuously to >7.0 mm in March or April, and then dropped again. In March and April, the average number of eggs and juveniles female(-1) was similar to 100 eggs and 55 juveniles, while during the summer/early fall the average number of eggs female(-1) was < 20 and that of juveniles female(-1) war < 10. Many juveniles grew to large sizes ( > 1.4 mm) on their mothers' whips in winter/early spring but not in the summer/fall. The average number of amphipods at the study site was low in late summer/early fall (< 50 individuals m(-2)), increased steadily during the winter? and reached peak densities of > 3000 individuals m(-2) in April 1996 (>1600 individuals m(-2) in May 1997), after which densities decreased again. The decrease of the D. monacanthus population at the study site coincided with a strong increase of amphipods found pelagic in the water column. This behavioural shift occurred when temperatures increased and benthic predators became more abundant and active on shallow soft-bottoms, suggesting that D. monacanthus at the study site is strongly affected by predation. The effects are direct (by predation on amphipods) and indirect (by reducing duration of extended parental care and enhancing pelagic movements). Both extended parental care and pelagic movements are important behavioural traits of D. monacanthus land other marine amphipods), and significantly affect its population dynamics. C1 Univ Maine, Darling Marine Ctr, Walpole, ME 04573 USA. RP Thiel, M (reprint author), Smithsonian Marine Stn, 5612 Old Dixie Highway, Ft Pierce, FL 34946 USA. NR 62 TC 11 Z9 12 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD SEP PY 1998 VL 132 IS 2 BP 209 EP 221 DI 10.1007/s002270050387 PG 13 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 129FT UT WOS:000076453700005 ER PT J AU Krot, AN Petaev, MI Scott, ERD Choi, BG Zolensky, ME Keil, K AF Krot, AN Petaev, MI Scott, ERD Choi, BG Zolensky, ME Keil, K TI Progressive alteration in CV3 chondrites: More evidence for asteroidal alteration SO METEORITICS & PLANETARY SCIENCE LA English DT Article; Proceedings Paper CT Workshop on Parent Body and Nebular Modification of Chrondritic Materials CY JUL 16-19, 1997 CL UNIV HAWAII, MAUI, HAWAII HO UNIV HAWAII ID ALLENDE CARBONACEOUS CHONDRITE; HIGH-TEMPERATURE CONDENSATION; AQUEOUS ALTERATION; SOLAR NEBULA; REFRACTORY INCLUSIONS; THERMAL METAMORPHISM; DARK INCLUSIONS; VIGARANO TYPE; PARENT BODY; METEORITE AB The oxidized CV3 chondrites can be divided into two major subgroups or lithologies, Ball-like (CV3(oxB)) and Allende-like (CV3(oxA)), in which chondrules, calcium-aluminum-rich inclusions (CAIs) and matrices show characteristic alteration features (Weisberg et al., 1997; Krot et al., 1997d; Kimura and Ikeda, 1997). The CV3(oxB) lithology is present in Bail, Kaba, parts of the Mokoia breccia and, possibly, in Grosnaja and Allan Hills (ALH) 85006. It is characterized by the presence of the secondary low-Ca phyllosilicates (saponite and sodium phlogopite), magnetite, Ni-rich sulfides, fayalite (Fa(>90)), Ca-Fe-rich pyroxenes (Fs(10-50)Wo(45-50)) and andradite. Phyllosilicates replace primary Ca-rich minerals in chondrules and CAIs, which suggests mobilization of Ca during aqueous alteration. Magnetite nodules are replaced to various degrees by fayalite, Ca-Fe-rich pyroxenes and minor andradite. Fayalite veins crosscut fine-grained rims around chondrules and extend into the matrix. Thermodynamic analysis of the observed reactions indicates that they could have occurred at relatively low temperatures (<300 degrees C) in the presence of aqueous solutions. Oxygen isotopic compositions of the coexisting magnetite and fayalite plot close to the terrestrial fractionation line with large Delta(18)O(fyalite-magnetite) fractionation (similar to 20 parts per thousand). We infer that phyllosilicates, magnetite, fayalite, Ca-Fe-rich pyroxenes and andradite formed at relatively low temperatures (<300 degrees C) by fluid-rock interaction in an asteroidal environment. Secondary fayalite and phyllosilicates are virtually absent in chondrules and CAIs in the CV3(oxA) lithology, which is present in Allende and its dark inclusions, Axtell, ALHA81258, ALH 84028, Lewis Cliff(LEW) 86006, and parts of the Mokoia and Vigarano breccias. Instead secondary nepheline, sodalite, and fayalitic olivine are common. Fayalitic olivine in chondrules replaces low-Ca pyroxenes and rims and veins forsterite grains; it also forms coarse lath-shaped grains in matrix. Secondary Ca-Fe-rich pyroxenes are abundant. We infer that the CV3(oxA) lithology experienced alteration at higher temperatures than the CV3(oxB) lithology. The presence of the reduced and CV3(oxA) lithologies in the Vigarano breccia and CV3(oxA) and CV3(oxB) lithologies in the Mokoia breccia indicates that all CV3 chondrites came from one heterogeneously altered asteroid. The metamorphosed clasts in Mokoia (Krot and Hutcheon, 1997) may be rare samples of the hotter interior of the CV asteroid. We conclude that the alteration features observed in the oxidized CV3 chondrites resulted from the fluid-rock interaction in an asteroid during progressive metamorphism of a heterogeneous mixture of ices and anhydrous materials mineralogically similar to the reduced CV3 chondrites. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Los Angeles, Dept Earth & Planetary Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. NASA, Earth Sci & Solar Syst Explorat Div, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Hawaii Ctr Volcanol, Honolulu, HI USA. RP Krot, AN (reprint author), Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. EM sasha@pgd.hawaii.edu NR 94 TC 164 Z9 166 U1 1 U2 18 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 SEP PY 1998 VL 33 IS 5 BP 1065 EP 1085 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 131BD UT WOS:000076555100013 ER PT J AU Petaev, MI Wood, JA AF Petaev, MI Wood, JA TI The condensation with partial isolation (CWPI) model of condensation in the solar nebula SO METEORITICS & PLANETARY SCIENCE LA English DT Article; Proceedings Paper CT Workshop on Parent Body and Nebular Modification of Chrondritic Materials CY JUL 16-19, 1997 CL UNIV HAWAII, MAUI, HAWAII HO UNIV HAWAII ID MODERATELY VOLATILE ELEMENTS; ORDINARY CHONDRITES; BEARING CHONDRULES; ABUNDANCES; CLASTS; ORIGIN AB We have developed a nebular condensation model and a computational routine that potentially can account for the unequilibrated mineral assemblages in chondritic meteorites. The model assumes that as condensation proceeds, a specified fraction (called the isolation degree, xi) of the existing condensate is steadily withdrawn from reactive contact with the residual gas, presumably as a result of the growth and aggregation of condensed mineral grains. The isolated condensates may remain in the condensing system as coarse inert objects; whereas, the mineral grains that are still in reactive contact with residual nebular gases are in the form of fine dust. This paper describes the condensation with partial isolation (CWPI) model of condensation and uses it to study condensation in a nebula of solar composition at a total pressure of 10(-5) bar. The systematic isolation of condensates from residual nebular gases has profound effects on the condensation sequence. At xi values <0.2%, the condensation sequence is essentially independent of the isolation degree and identical to the classic condensation sequence. At xi values >2.5%, the condensation sequence is also independent of the isolation degree and closely resembles the "inhomogeneous accretion model" or "chemical disequilibrium model" of condensation. In the intermediate range of xi values, the character of the condensation sequence is very sensitive to the degree of chemical fractionation caused by condensate isolation. The mineralogy of chondritic meteorites is not consistent with condensation sequences having xi > 2.5; this is an upper limit on the xi values that is characteristic of condensation in the solar nebula. The mineralogy and chemistry of carbonaceous and enstatite chondrites can be explained by accretion of isolated condensates formed at xi values of less than or equal to 0.1% and 0.7-1.5%, respectively, providing that segregation of the inert coarse objects and fine reactive dust occurred in the nebula. Segregation of these two categories of condensate may have been responsible for the observed volatility-based chemical fractionations among chondritic meteorites. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Petaev, MI (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM mpetaev@cfa.harvard.edu NR 41 TC 80 Z9 80 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 SEP PY 1998 VL 33 IS 5 BP 1123 EP 1137 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 131BD UT WOS:000076555100017 ER PT J AU Weil, SE AF Weil, SE TI Exhibiting authenticity SO MUSEUM NEWS LA English DT Book Review C1 Smithsonian Inst, Ctr Museum Studies, 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 SEP-OCT PY 1998 VL 77 IS 5 BP 25 EP + PG 0 WC Art SC Art GA 114UU UT WOS:000075628200006 ER PT J AU Ferrucci, MS Acevedo-Rodriguez, P AF Ferrucci, MS Acevedo-Rodriguez, P TI Cardiospermum cuchujaquense (Sapindaceae), a new species from Sonora, Mexico SO NOVON LA English DT Article AB A new species, Cardiospermum cuchujaquense from Sonora, Mexico, is described and illustrated. The new species belongs to C. sect. Carphospermum, which is characterized by the presence of chaffy or scaly trichomes. With the discovery of C. cuchujaquense, a pattern of disjunct distribution is documented for C. sect. Carphospermum. C1 Inst Bot Nordeste, RA-3400 Corrientes, Argentina. Smithsonian Inst, Dept Bot, Natl Museum Nat Hist, Washington, DC 20560 USA. RP Ferrucci, MS (reprint author), Inst Bot Nordeste, CC 209, RA-3400 Corrientes, Argentina. NR 5 TC 6 Z9 6 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 FAL PY 1998 VL 8 IS 3 BP 235 EP 238 DI 10.2307/3392008 PG 4 WC Plant Sciences SC Plant Sciences GA 121PG UT WOS:000076022100007 ER PT J AU Wagner, WL AF Wagner, WL TI Species status for a Sonoran Desert annual member of Oenothera sect. Anogra (Onagraceae) SO NOVON LA English DT Article AB The taxon most recently known as Oenothera avita W. Klein subsp. arizonica (Munz) Klein is here elevated to species level. It is easily distinguished from the perennial taxa of this complex, currently treated as three subspecies of O. californica, by its annual habit with a taproot, stems thickened near the base and tapering toward the apex, buds with conspicuous purple spots, each spot at the base of a long hair, longer attenuate capsules, and pinnatifid leaves. C1 Natl Museum Nat Hist, Smithsonian Inst, Dept Bot, MRC 166, Washington, DC 20560 USA. RP Wagner, WL (reprint author), Natl Museum Nat Hist, Smithsonian Inst, Dept Bot, MRC 166, Washington, DC 20560 USA. NR 11 TC 3 Z9 3 U1 2 U2 3 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 FAL PY 1998 VL 8 IS 3 BP 307 EP 310 DI 10.2307/3392027 PG 4 WC Plant Sciences SC Plant Sciences GA 121PG UT WOS:000076022100026 ER PT J AU Wagner, WL Lorence, DH AF Wagner, WL Lorence, DH TI A new, dioecious species of Hedyotis (Rubiaceae) from Kaua'i, Hawaiian Islands, and the taxonomy of Kaua'i Hedyotis schlechtendahliana resolved SO NOVON LA English DT Article AB A new, cliff-dwelling species, Hedyotis flynnii, is described from the Hawaiian island of Kaua'i. It is distinguished by its conspicuously reticulate leaf venation, reduced leaves, and greenish yellow or sometimes white corollas. Based on morphological observations, it appears to be the first species in the genus known to have a dioecious breeding system. Hedyotis flynnii also expresses a strong corolla size dimorphism, with staminate flowers much larger than the pistillate. The taxonomy of the polymorphic species Hedyotis schlechtendahliana also is reconsidered recognizing the north-western Kaua'i populations as Hedyotis schlechtendahliana subsp. waimeae, characterized by stiffly chartaceous to coriaceous reticulate leaves, open inflorescences, and subulate bracts and calyx lobes. C1 Natl Museum Nat Hist, Smithsonian Inst, Dept Bot, Washington, DC 20560 USA. Natl Trop Bot Garden, Lawai, HI 96765 USA. RP Wagner, WL (reprint author), Natl Museum Nat Hist, Smithsonian Inst, Dept Bot, MRC-166, Washington, DC 20560 USA. NR 5 TC 5 Z9 7 U1 1 U2 3 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 FAL PY 1998 VL 8 IS 3 BP 311 EP 317 DI 10.2307/3392028 PG 7 WC Plant Sciences SC Plant Sciences GA 121PG UT WOS:000076022100027 ER PT J AU Wagner, WL Lorence, DH AF Wagner, WL Lorence, DH TI A new species of Wikstroemia (Thymelaeaceae) from Hiva Oa, Marquesas Islands SO NOVON LA English DT Article AB A new species, Wikstroemia johnplewsii, is described and illustrated. This distinctive species is restricted to upper montane mesic to wet forest on the island of Hiva Oa (Marquesas Islands in French Polynesia); it differs from the only other Wikstroemia species in the Marquesas, W. coriacea, which occurs widely in Polynesia, by its ovate-elliptic to suborbicular, subsessile leaves and long, 9-27-flowered, racemose inflorescences with an elongate peduncle and inflorescence axis. C1 Natl Museum Nat Hist, Smithsonian Inst, Dept Bot, Washington, DC 20560 USA. Natl Trop Bot Garden, Lawai, HI 96765 USA. RP Wagner, WL (reprint author), Natl Museum Nat Hist, Smithsonian Inst, Dept Bot, MRC-166, Washington, DC 20560 USA. NR 3 TC 0 Z9 1 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 FAL PY 1998 VL 8 IS 3 BP 318 EP 320 DI 10.2307/3392029 PG 3 WC Plant Sciences SC Plant Sciences GA 121PG UT WOS:000076022100028 ER PT J AU Naraschewski, M Stamper-Kurn, DM AF Naraschewski, M Stamper-Kurn, DM TI Analytical description of a trapped semi-ideal Bose gas at finite temperature SO PHYSICAL REVIEW A LA English DT Article ID EINSTEIN CONDENSATION; FRACTION AB Present experiments with Bose condensed gases can be largely described by a semi-ideal two-gas model. In this model, the condensate is influenced only by the mean-field repulsion among condensed atoms, while the thermal cloud is considered an ideal gas confined by an effective potential that consists of the external trap and the mean-field repulsion by the condensate. This simple, intuitive model provides explicit analytical expression for the density distributions of the condensate and the thermal component. It describes the reduction of the condensate fraction relative to that of an ideal gas as a consequence of the positive chemical potential due to interactions in the condensate. C1 Harvard Univ, Dept Phys, Jefferson Lab, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Elect Res Lab, Cambridge, MA 02139 USA. RP Naraschewski, M (reprint author), Harvard Univ, Dept Phys, Jefferson Lab, Cambridge, MA 02138 USA. RI Stamper-Kurn, Dan/B-5442-2015 OI Stamper-Kurn, Dan/0000-0002-4845-5835 NR 16 TC 57 Z9 60 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD SEP PY 1998 VL 58 IS 3 BP 2423 EP 2426 DI 10.1103/PhysRevA.58.2423 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 116MY UT WOS:000075730200098 ER PT J AU Timmermans, E Trammell, GT Hannon, JP AF Timmermans, E Trammell, GT Hannon, JP TI Spin holography SO PHYSICAL REVIEW B LA English DT Article ID POLARIZED PHOTOELECTRON DIFFRACTION; SCATTERING; EMISSION AB The interference of the directly emitted photoelectron wave and the wave scattered coherently by neighboring atoms gives holographic fringes in the photoelectron emission intensity I((R) over cap). In the electron-emission holography technique in surface physics, I((R) over cap) is inverted holographically to give a three-dimensional image of the environment of the source atom. Earlier [E. M. E. Timmermans, G. T. Trammell, and J. P. Hannon, Phys. Rev. Lett. 72, 832 (1994); J. Appl. Phys. 73, 6138 (1993)], we pointed out that the polarization pattern P((R) over cap) similarly can be viewed as a hologram of the spin environment of the source atom by virtue of the exchange scattering of the photoelectron by the neighboring atoms. In this paper, we point out that spin-orbit correlations in the photoelectron initial state are responsible for holographic spin-dependent contributions to the intensity hologram I((R) over cap), even if the directly emitted photoelectrons are unpolarized. This remarkable result implies that the emission intensity contains spin information just as the polarization pattern P((R) over cap). Although the spin-dependent signal in the hologram is rather small (similar to 5% in most cases of interest), we show how spin information can be extracted from the intensity hologram, making use of the point symmetry of the environment of the source atom. This way of analyzing photoelectron intensity holograms to extract short-range spin information opens up a new avenue for surface magnetism studies. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Rice Univ, Dept Phys, Houston, TX 77251 USA. RP Timmermans, E (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 29 TC 3 Z9 3 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 1 PY 1998 VL 58 IS 9 BP 5637 EP 5648 DI 10.1103/PhysRevB.58.5637 PG 12 WC Physics, Condensed Matter SC Physics GA 116JA UT WOS:000075720100077 ER PT J AU Krist, JE Golimowski, DA Schroeder, DJ Henry, TJ AF Krist, JE Golimowski, DA Schroeder, DJ Henry, TJ TI Characterization and subtraction of well-exposed HST NICMOS camera 2 point-spread functions for a survey of very low mass companions to nearby stars SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID HUBBLE-SPACE-TELESCOPE; BROWN DWARFS; SEARCH; PHASE; IMAGE AB conducting a search for very low mass (M < 0.2 M.) companions of stars within IO pc of the Sun using the NICMOS infrared camera on the Hubble Space Telescope. Thr highly exposed images ol each target star are subtracted from the NICMOS Camera 2 (NIC2) field using previously observed stars so that faint companions may be detected. We have characterized the NIC2 point-spread function (PSF) at large angles and measured encircled energies useful for point-source aperture photometry corrections. The Camera 2 PSFs have elliptical diffraction rings and asymmetric diffraction spike banding patterns that appear to be caused by a misalignment of the NICMOS cold mask relative to the telescope obscurations. The mask's position appears to vary about a general offset. creating a time-dependent diffraction pattern. We have devised a procedure for selecting target star images that provide the best PSF subtractions. The ultimate detection limits of our survey are F110W similar to 21 and F222M similar to 19.5, roughly approximating J and K measurements, respectively. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Ctr Astrophys Sci, Baltimore, MD 21218 USA. Beloit Coll, Dept Phys & Astron, Beloit, WI 53511 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Krist, JE (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 17 TC 46 Z9 46 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD SEP PY 1998 VL 110 IS 751 BP 1046 EP 1058 DI 10.1086/316221 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 125CM UT WOS:000076219900007 ER PT J AU Asaki, Y Shibata, KM Kawabe, R Roh, DG Saito, M Morita, KI Sasao, T AF Asaki, Y Shibata, KM Kawabe, R Roh, DG Saito, M Morita, KI Sasao, T TI Phase compensation experiments with the paired antennas method - 2. Millimeter-wave fringe correction using centimeter-wave reference SO RADIO SCIENCE LA English DT Article ID ANGULAR SEPARATION; SPACE GEODESY; RADIO-SOURCES; ARRAY; INTERFEROMETRY; TROPOSPHERE; ASTROMETRY AB An experiment for compensating interferometer phase fluctuations due to the turbulent troposphere was conducted with the paired antennas method (PAM) using different sky frequencies for a target and reference source. A celestial source 3C279 was observed at 146.81 GHz with the Nobeyama millimeter array (NMA), while a geostationary satellite was observed as a reference source at 19.45 GHz with commercially available antennas. Each of the antennas was installed near one of the NMA antennas, thus giving us 10 pairs of nearly parallel baselines up to 316 m. Large fluctuations in the interferometer phase of 3C279 were mostly eliminated on almost all baselines by subtracting the reference phase multiplied by a ratio of the observing frequencies. The standard deviations of the compensated interferometer phase were under the level of 20 degrees where the angular separation between the two sources was within 2 degrees, while those of the original phase were typically at the level of 40 degrees-50 degrees. The phase compensation was much improved to the level of the differential excess path length of 0.06-mm rms (11 degrees at 146.81 GHz) in inserting a time lag proportional to the separation angle to the reference phase time series. These results have practical significance for the millimeter- or submillimeter-wave interferometry because there is rarely a suitable reference source in the vicinity of scientifically interesting sources at such high frequencies. The present experiment shows that it is quite effective in the PAM to use the reference phase at centimeter-wave for compensating the millimeter-wave phase for future large millimeter-wave arrays. C1 Natl Astron Observ, Tokyo 181, Japan. Natl Astron Observ, Nobeyama Radio Observ, Minamisa Ku, Nagano 38413, Japan. Korea Astron Observ, Taeduk Radio Astron Observ, Yusong Ku, Taejon 305348, South Korea. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Astron Observ, Mizusawa Astrogeodynam Observ, Iwate 023, Japan. RP Asaki, Y (reprint author), Natl Astron Observ, 2-21-1 Osawa, Tokyo 181, Japan. NR 32 TC 29 Z9 29 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD SEP-OCT PY 1998 VL 33 IS 5 BP 1297 EP 1318 DI 10.1029/98RS01607 PG 22 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 125UL UT WOS:000076255400004 ER PT J AU Parsons, WFJ Ehrenfeld, JG Handel, SN AF Parsons, WFJ Ehrenfeld, JG Handel, SN TI Vertical growth and mycorrhizal infection of woody plant roots as potential limits to the restoration of woodlands on landfills SO RESTORATION ECOLOGY LA English DT Article ID ECTOMYCORRHIZA FORMATION; SOUTHWEST OREGON; CLEAR-CUTS; SOIL; SURVIVAL; FUNGI; SEEDLINGS AB We assessed the vertical growth and mycorrhizal infection of woody plant roots on a closed landfill, using tree and shrub clusters that had been previously installed in patches of increasing size to establish protocols for woodland restoration. The density of the fine roots of shrubs, which had poor-to-moderate mycorrhizal infection, decreased strongly with increasing depth. Oak (Quercus) seedlings planted within and outside patches were assessed for ectomycorrhizal infection. Oak root systems were mycorrhizal, but root-tip proliferation was improved and ectomycorrhizal composition was influenced by woody debris in the mineral soil. Most surviving oaks were found within patches, but all seedlings showed poor growth: most taproots were deflected horizontally above the boundary between surface soil and subsoil layers (greater than or equal to-15 cm). Abrupt decreases in pH between surface and subsurface horizons (6.9 versus 5.3), together with poor drainage and aeration of the latter soil, were probably responsible for poor root growth. Root growth of greenhouse-grown pine and maple seedlings was similarly restricted in pots packed with top-soil over subsoil material. Our results suggest that many current specifications for the cover of closed landfills will not permit restoration of native woody plant communities because of physical limitations to root growth and infectivity. The structure of the engineered soil must address basic plant growth requirements as well as traditional concerns of drainage and barrier protection. C1 Rutgers State Univ, Dept Ecol Evolut & Nat Resources, New Brunswick, NJ 08903 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Parsons, WFJ (reprint author), Rutgers State Univ, Dept Ecol Evolut & Nat Resources, New Brunswick, NJ 08903 USA. NR 35 TC 10 Z9 10 U1 3 U2 12 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1061-2971 J9 RESTOR ECOL JI Restor. Ecol. PD SEP PY 1998 VL 6 IS 3 BP 280 EP 289 DI 10.1046/j.1526-100X.1998.06310.x PG 10 WC Ecology SC Environmental Sciences & Ecology GA 119XJ UT WOS:000075927800007 ER PT J AU Guzman, HM Guevara, CA AF Guzman, HM Guevara, CA TI Bocas del Toro, Panama coral reefs: I. Distribution, structure and conservation state of continental reefs in Laguna de Chiriqui and Bahia Almirante SO REVISTA DE BIOLOGIA TROPICAL LA Spanish DT Article DE coral reef; biodiversity; Caribbean; reef assessment; ecology ID SCLERACTINIAN CORALS; COMMUNITY STRUCTURE; CARIBBEAN COAST; PATCH REEFS; WEST-INDIES; COSTA-RICA; EUTROPHICATION; SEDIMENT; POLLUTION; MORTALITY AB The distribution of continental reefs is presented along 83 km of shore within Bahia Almirante and 125 km within the Chiriqui Lagoon, Bocas del Toro, Panama. Reef community structure (diversity, cover, zonation) is described on 15 coral reefs for both regions, representing the diversity of hydrological and orographical conditions affecting the coastal tone. The coral reefs found in Bahia Almirante are well developed down to a maximum depth of 23 m, and a diversity of hard corals of 33 species, which represents approximately a 53% of the total diversity known for Panama. Coral cover observed for the studied region ranged between 20% and 50% depending on the depth, and a total average of 35% is estimated, nearly twice the cover informed for other regions of Panama (San Bias), where it is presumed that the reefs are better protected from human disturbances. Vertical distribution and composition of species are similar across the area; Porites furcata dominates shallow reefs down to 2 m depth, with a cover estimated at 90%, followed by a zone dominated by Agaricia tenuifolia (40%) down to 6 m depth, followed by a tone composed mainly of A. tenuifolia (15%), Madracis mirabilis (7%), and Siderastrea siderea (5%) down to 15 m deep, and finishing in a deeper zone dominated by coralline algae and the coral S. siderea. The existence of a semi-continuous Porites furcata fringing reef of ca. 22 km in length, borders the entire coastal zone of Ensenada Grande de Almirante, is informed for the first time for the region. Sponges, second sessile organisms in importance, ate widely distributed in all reefs with a diversity of 31 species and average cover of 6%. Curiously, the highest algae coverage was found in one reef (10%) while the remaining reefs presented an average cover of 4%. Only one coral reef was found in the Chiriqui Lagoon with development limited to 3 m, a diversity of corals no higher than 7 species, and coral cover of 24% (Porites furcata). The coast of the Chiriqui Lagoon is affected by continuous sediment discharges coming from various rivers, mainly the Cricamola, Mananti, Uyama, Guarumo, and Cauchero, whose plumes of freshwater and silt extend for many kilometers, limiting the distribution and development of coral reef communities. The vertical distribution, composition, and dominance of certain coral species in the reefs described here (e.g., Siderastrea siderea, Porites furcata, Agaricia tenuifolia, Madracis decactis, and M. mirabilis) indicate that these communities were formed adapting gradually to unfavorable conditions in water quality (lower salinity, low light penetration) which has limited a more vigorous reef development, and perhaps more diverse community. These species, in spite of being quite resistant to environmental changes and building healthy reefs in waters of low clarity presently live near their limits of ecophysiological tolerance, which makes them particularly vulnerable to punctuated changes in me environment. It is expected that any unplanned development project in the region might increase sedimentation toward the coastal zone, which could weaken all reef organisms, affecting ecosystem function. C1 Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 65 TC 43 Z9 47 U1 1 U2 17 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 SEP PY 1998 VL 46 IS 3 BP 601 EP 623 PG 23 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 174XZ UT WOS:000079063000014 ER PT J AU Tucker, W AF Tucker, W TI X-ray telescope SO SMITHSONIAN LA English DT Letter C1 AXAF Sci Ctr, Smithsonian Astrophys Observ, Cambridge, MA USA. RP Tucker, W (reprint author), AXAF Sci Ctr, Smithsonian Astrophys Observ, Cambridge, MA USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU SMITHSONIAN ASSOCIATES PI WASHINGTON PA 900 JEFFERSON DRIVE, WASHINGTON, DC 20560 USA SN 0037-7333 J9 SMITHSONIAN JI Smithsonian PD SEP PY 1998 VL 29 IS 6 BP 18 EP 18 PG 1 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA 113KN UT WOS:000075550300010 ER PT J AU Briscoe, NL AF Briscoe, NL TI Praise from the Smithsonian SO SOLID STATE TECHNOLOGY LA English DT Letter C1 Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. RP Briscoe, NL (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PENNWELL PUBL CO SOLID STATE TECHNOLOGY OFFICE PI NASHUA PA TEN TARA BLVD 5TH FLOOR, NASHUA, NH 03062-2801 USA SN 0038-111X J9 SOLID STATE TECHNOL JI Solid State Technol. PD SEP PY 1998 VL 41 IS 9 BP 18 EP 18 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 115VK UT WOS:000075686500002 ER PT J AU Huelsenbeck, JP AF Huelsenbeck, JP TI Systematic bias in phylogenetic analysis: Is the Strepsiptera problem solved? SO SYSTEMATIC BIOLOGY LA English DT Editorial Material ID MAXIMUM-LIKELIHOOD ALIGNMENT; DNA-SEQUENCES; EVOLUTIONARY RATES; GUINEA-PIG; PARSIMONY; SUBSTITUTION; MODEL; SIMULATION; INFERENCE; SUCCESS C1 Smithsonian Museum Support Ctr, Lab Mol Systemat, Suitland, MD 20746 USA. RP Huelsenbeck, JP (reprint author), Smithsonian Museum Support Ctr, Lab Mol Systemat, 4210 Silver Hall Rd, Suitland, MD 20746 USA. RI Huelsenbeck, John/C-6398-2013 NR 52 TC 117 Z9 118 U1 1 U2 6 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 1063-5157 J9 SYST BIOL JI Syst. Biol. PD SEP PY 1998 VL 47 IS 3 BP 519 EP 537 PG 19 WC Evolutionary Biology SC Evolutionary Biology GA 124FZ UT WOS:000076172900012 PM 12066692 ER PT J AU McDaniel, CJ Dunn, BJ Weldon, PJ AF McDaniel, CJ Dunn, BJ Weldon, PJ TI Citronellol and citronellyl esters from the paracloacal glands of the broad-snouted caiman, Caiman latirostris (Crocodylia, reptilia) SO ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES LA English DT Article ID LIPIDS; SECRETIONS; TRIGONATUS AB The secretions of the paracloacal glands of an adult male broad-snouted caiman (Caiman latirostris) were analyzed by GC/MS. 3,7-Dimethyl-6-octen-1-ol (citronellol) and four citronellyl esters, with acid moieties ranging from two to five carbons, were identified. Squalene, beta-farnesene, and straight-chain esters also were observed. C1 Smithsonian Inst, Conservat & Res Ctr, Front Royal, VA 22630 USA. So Forest Expt Stn, Forestry Sci Lab, Gulfport, MS 39505 USA. RP Weldon, PJ (reprint author), Smithsonian Inst, Conservat & Res Ctr, 1500 Remount Rd, Front Royal, VA 22630 USA. NR 7 TC 3 Z9 4 U1 0 U2 0 PU VERLAG Z NATURFORSCH PI TUBINGEN PA POSTFACH 2645, W-7400 TUBINGEN, GERMANY SN 0939-5075 J9 Z NATURFORSCH C JI Z.Naturforsch.(C) PD SEP-OCT PY 1998 VL 53 IS 9-10 BP 932 EP 934 PG 3 WC Biochemistry & Molecular Biology; Pharmacology & Pharmacy SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy GA 135FJ UT WOS:000076790000026 ER PT J AU Geller, MJ AF Geller, MJ TI The black ribbon SO SCIENCE LA English DT Editorial Material C1 Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Geller, MJ (reprint author), Harvard Smithsonian Ctr Astrophys, Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. NR 0 TC 0 Z9 0 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 AUG 28 PY 1998 VL 281 IS 5381 BP 1278 EP 1279 DI 10.1126/science.281.5381.1278 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 115LQ UT WOS:000075666800013 ER PT J AU Baker, MT AF Baker, MT TI Thermal history studies in ancient and modern rubber. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Smithsonian Ctr Mat Res & Educ, Suitland, MD 20746 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 23 PY 1998 VL 216 MA 624-POLY BP U202 EP U202 PN 3 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 107WZ UT WOS:000075235100621 ER PT J AU Heller, EJ Harai, K AF Heller, EJ Harai, K TI New insights into the dynamics of polyatomic molecules as seen through vibrogram spectral analysis. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Dept Phys, Cambridge, MA 02138 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 23 PY 1998 VL 216 MA 395-PHYS BP U774 EP U774 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 107WY UT WOS:000075235002328 ER PT J AU Tumosa, CS McCormick-Goodhart, MH Mecklenburg, MF AF Tumosa, CS McCormick-Goodhart, MH Mecklenburg, MF TI The physical properties of photographic film polymers subjected to cold storage environments. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Smithsonian Ctr Mat Res & Educ, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 23 PY 1998 VL 216 MA 620-POLY BP U201 EP U201 PN 3 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 107WZ UT WOS:000075235100617 ER PT J AU Tumosa, CS Erhardt, D Mecklenburg, MF AF Tumosa, CS Erhardt, D Mecklenburg, MF TI Chemical and physical changes in naturally and artificially aged cellulose. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Smithsonian Ctr Mat Res & Educ, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 23 PY 1998 VL 216 MA 037-CELL BP U341 EP U341 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 107WX UT WOS:000075234900953 ER PT J AU Botschwina, P Heyl, A Chen, W McCarthy, MC Grabow, JU Travers, MJ Thaddeus, P AF Botschwina, P Heyl, A Chen, W McCarthy, MC Grabow, JU Travers, MJ Thaddeus, P TI The isocyanopolyynes HC4NC and HC6NC: Microwave spectra and ab initio calculations SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULES; ISOCYANOACETYLENE; ASTROCHEMISTRY; TMC-1; HC5N AB Rotational spectra of HC4NC and HC6NC, linear molecules' of interest to interstellar cloud chemistry, were recorded by Fourier transform microwave spectroscopy, and the ground state rotational constants were determined to be 1401.18227(7) and 582.5203(1) MHz. Nitrogen quadrupole hyperfine structure could be observed for HC4NC. On the basis of coupled cluster calculations including connected triple substitutions accurate equilibrium structures (uncertainty in bond lengths ca. 0.0065 Angstrom) could be established for both species. The equilibrium dipole moments,: predicted to be -3-25 and -3.49 D for HC4NC and HC6NC, respectively, exhibit large correlation effects of 30% and 33% (C) 1998 American Institute of Physics. [S0021-9606(98)01032-0]. C1 Univ Gottingen, Inst Phys Chem, D-37077 Gottingen, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Botschwina, P (reprint author), Univ Gottingen, Inst Phys Chem, Tammannstr 6, D-37077 Gottingen, Germany. EM pbotsch@gfwdg.de OI McCarthy, Michael/0000-0001-9142-0008 NR 34 TC 27 Z9 27 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 22 PY 1998 VL 109 IS 8 BP 3108 EP 3115 DI 10.1063/1.476515 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 114ZN UT WOS:000075639200020 ER PT J AU Hameury, JM Menou, K Dubus, G Lasota, JP Hure, JM AF Hameury, JM Menou, K Dubus, G Lasota, JP Hure, JM TI Accretion disc outbursts: a new version of an old model SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; instabilities; binaries : close; novae, cataclysmic variables ID DWARF NOVA OUTBURSTS; INSTABILITY MODEL; CATACLYSMIC VARIABLES; BLACK-HOLES; VERTICAL STRUCTURE; OPACITY TABLES; BINARY-SYSTEMS; COOLING FRONTS; LIMIT-CYCLE; IP-PEGASI AB We have developed 1D time-dependent numerical models of accretion discs, using an adaptive grid technique and an implicit numerical scheme, in which the disc size is allowed to vary with time. The code fully resolves the cooling and heating fronts propagating in the disc, We show that models in which the radius of the outer edge of the disc is fixed produce incorrect results, from which probably incorrect conclusions about the viscosity law have been inferred. In particular we show that outside-in outbursts are possible when a standard bimodal behaviour of the Shakura-Sunyaev viscosity parameter alpha is used. We also discuss to what extent insufficient grid resolution has limited the predictive power of previous models, We find that the global properties (magnitudes, etc.) of transient discs can be addressed by codes using a high, but reasonable, number of fixed grid points. However, the study of the detailed physical properties of the transition fronts generally requires resolutions which are out of reach of fixed grid codes. It appears that most time-dependent models of accretion discs published in the literature have been limited by resolution effects, improper outer boundary conditions, or both. C1 Observ Strasbourg, UMR 7550 CNRS, F-67000 Strasbourg, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Observ Paris, Dept Astrophys Relativiste & Cosmol, Meudon Sect, UPR 176 CNRS, F-92195 Meudon, France. Observ Paris, Dept Astrophys Relativiste & Cosmol, Meudon Sect, UPR 173 CNRS, F-92195 Meudon, France. RP Hameury, JM (reprint author), Observ Strasbourg, UMR 7550 CNRS, 11 Rue Univ, F-67000 Strasbourg, France. NR 53 TC 142 Z9 142 U1 1 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 AUG 21 PY 1998 VL 298 IS 4 BP 1048 EP 1060 DI 10.1046/j.1365-8711.1998.01773.x PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 117LA UT WOS:000075781700009 ER PT J AU Schlegel, EM AF Schlegel, EM TI Serendipitous discovery of a bright narrow line X-ray galaxy SO NEW ASTRONOMY LA English DT Article DE X-rays; galaxies : individual ID MEDIUM SENSITIVITY SURVEY; ROSAT SURVEY; EMISSION; CATALOG; SPECTRA AB I report on the discovery of a bright (similar to 0.15 counts s(-1), ROSAT band) serendipitous X-ray source in the ROSAT PSPC field of the cataclysmic variable EP Dra. The apparent optical counterpart shows the required optical characteristics of a Narrow Line X-ray Galaxy (NLXG) with a redshift of similar to 0.107. The X-ray luminosity can not be explained by starbursts. The H-beta luminosity is similar to 1041 ergs s(-1). (C) 1998 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Schlegel, EM (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 33 TC 0 Z9 0 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 21 PY 1998 VL 3 IS 7 BP 427 EP 434 DI 10.1016/S1384-1076(98)00023-2 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 119FR UT WOS:000075885800001 ER PT J AU Pelt, J Schild, R Refsdal, S Stabell, R AF Pelt, J Schild, R Refsdal, S Stabell, R TI Microlensing on different timescales in the lightcurves of QSO 0957+561 A,B SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE methods : statistical; methods : data analysis; quasars : individual : 0957+561A,B; gravitational lensing ID GRAVITATIONAL LENS 0957+561; TIME-DELAY; LIGHT-CURVE; QSO-0957+561; PHOTOMETRY; STARS; EVENT AB A statistical analysis of an extended data set on a time basis of 17 years of optical observations of the gravitationally lensed quasar 0957+561 is presented. We use all available photometry to estimate the time delay between A and B images as 416.3 +/- 1.7 days. Using this refined value we investigate basic statistical properties of the difference curve between the A and the time shifted B image. We find a significant variability of 0.25 mag on a time scale of 5 years, which we interpret as microlensing by compact objects in the lensing galaxy. We show that masses down to about 10(-5)M(.) may explain this microlensing event. Solar mass objects alone can more or less be excluded. However, a distribution of compact objects with a small fraction (less than or similar to 5%) in solar mass objects, seems to be possible. The best constrained parameter is the radius of the source which roughly should be 3 x 10(15)cm (within a factor of 3). With the present noise level an additional variability due to the microlensing on shorter time scales (days to months) is difficult to prove with a reasonable significance. All steps of the analysis are carried out by using simple statistical tests and with as few a priori assumptions as possible. C1 Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Tartu Astrophys Observ, EE-2444 Toravere, Estonia. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Hamburger Sternwarte, D-21029 Hamburg, Germany. Ctr Adv Study, N-0271 Oslo, Norway. RP Stabell, R (reprint author), Univ Oslo, Inst Theoret Astrophys, POB 1029, N-0315 Oslo, Norway. RI Pelt, Jaan/G-4916-2010 NR 25 TC 55 Z9 55 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 20 PY 1998 VL 336 IS 3 BP 829 EP 839 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 118FL UT WOS:000075827700018 ER PT J AU Tieftrunk, AR Megeath, ST Wilson, TL Rayner, JT AF Tieftrunk, AR Megeath, ST Wilson, TL Rayner, JT TI A survey for dense cores and young stellar clusters in the W 3 giant molecular cloud SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : W 3; W 3(OH); infrared : ISM : continuum; radio lines : ISM; ISM : clouds; structure ID STAR-FORMING REGION; VLA OBSERVATIONS; COMPLEX W3; SUBMILLIMETER OBSERVATIONS; RADIO-CONTINUUM; METHANOL MASERS; W3(OH); EMISSION; AMMONIA; LINES AB We simultaneously mapped the metastable (J,K) = (1,1) and (2,2) inversion lines of NH3 toward W 3 Main, W 3(OH), and the region between these two star-forming clouds with a 40 " angular resolution using the 100-m Effelsberg telescope. We observed a 120 square-arcminute region with 20 " spacing and a significantly higher sensitivity than previous maps. We also measured the (J,K) = (3,3) line of NH3 in 28 positions toward W 3 Main. For comparison with our NH3 survey, we present a K'-band (2.1 mu m) survey conducted by J. T. Rayner. The K'-band survey detects five distinct stellar clusters within the mapped region. In addition, we compare the NH3 survey to the CO (1-0) maps of the FCRAO 2nd quadrant survey (Heyer et al. 1998) and to the distribution of H II regions. The goals of this new survey are to a) map the extent of dense gas in the W 3 Main and W 3(OH) molecular clouds, b) search for previously undetected molecular cores in the intervening molecular cloud, c) measure column densities and T-kin for regions of strong NH3 emission, d) compare the distribution of the NH3 emission to that of the CO emission and e) study the relationship between the ammonia gas and sites of star formation as traced by stellar clusters and H II regions. In the W 3 Main cloud, we find strong and extended NH3 emission toward the relatively quiescent western core, but only weak and non-extended emission toward the highly active, star-forming, eastern core. We argue that the NH3 relative abundance in the eastern core is an order of magnitude lower than that in the western core. Southeast of W 3 Main we detect a new NH3 core, which we denote W 3 SE. From our NIR images we detect a jet toward this core. Toward the W 3(OH) cloud, we find an extended (2 x 1.3 pc), cold ammonia gas component. We show that the narrow plume of NH3(1,1), detected toward W 3(OH) in VLA maps, is part of a larger NH3 structure extending toward a chain of stellar clusters and nebulosities found in our NIR images. We find that the strong NH3 emission detected in the three cores covers 9% of the surveyed region. We estimate virial masses for each NH3 core and find that the total sum of the virial masses is 3300 MO. The total mass measured from the CO emission surveyed in this region is 1.6 x 10(4) Mo, thus 20% of the molecular gas in the surveyed region is found in the dense cores. This indicates that the dense cores fill only a small fraction of the total GMC and are concentrated in regions of active star formation. We also find extensive weak NH3 emission which covers one fourth of the surveyed region. This weak emission may trace gas with densities just sufficient to excite the NH3 emission (10(4) cm(-3)) as well as strongly beam-diluted knots and filaments. We compare in detail the distribution of NH3 cores, young stellar clusters, and H II regions, and discuss the effects of star formation on the NH3 cores. We also compare the results of our survey to those discussed by Lada (1992) from the CS (2-1) and 2.2 mu m surveys obtained for the Orion B giant molecular cloud by Lada et al. (1991a,1991b). C1 Max Planck Inst Radioastron, D-53121 Bonn, Germany. ESO La Silla, Santiago 19, Chile. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. MIT, Haystack Observ, Westford, MA 01886 USA. Univ Arizona, Sub Millimeter Telescope Observ, Tucson, AZ 85721 USA. Univ Hawaii, Astron Inst, Honolulu, HI 96822 USA. RP Tieftrunk, AR (reprint author), Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany. NR 76 TC 38 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 20 PY 1998 VL 336 IS 3 BP 991 EP 1006 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 118FL UT WOS:000075827700036 ER PT J AU Zehavi, I Riess, AG Kirshner, RP Dekel, A AF Zehavi, I Riess, AG Kirshner, RP Dekel, A TI A local Hubble bubble from type Ia supernovae? SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; cosmology : theory; galaxies : distances and redshifts; large-scale structure of universe; supernovae : general ID LIGHT-CURVE SHAPES; CAMPANAS REDSHIFT SURVEY; SPACE-TELESCOPE; GALAXY REDSHIFTS; VELOCITY-FIELD; TULLY-FISHER; CONSTANT; UNIVERSE; DIAGRAM; DISTANCE AB We analyze the monopole in the peculiar velocities of 44 Type Ia supernovae (SNe Ia) to test for a local void. The sample extends from 20 to 300 h(-1) Mpc, with distances, deduced from light-curve shapes, accurate to similar to 6%. Assuming Omega(m) = I and Omega(Lambda) = 0, the most significant deviation we find from the Hubble law is an outward how of 6.5% +/- 2.2% inside a sphere of radius 70 h(-1) Mpc, as would be produced by a void of similar to 20% underdensity surrounded by a dense shell. This shell roughly coincides with the local great walls. Monte Carlo analyses, using Gaussian errors or bootstrap resampling, show the probability for chance occurrence of this result out of a pure Hubble how to be similar to 2%. The monopole could be contaminated by higher moments of the velocity held, especially a quadrupole, which are not properly probed by the current limited sky coverage. The void would be less significant if Omega(m) is low and Omega(Lambda), is high. It would be more significant if one outlier is removed from the sample, or if the size of the void is constrained a priori. This putative void is not in significant conflict with any of the standard cosmological scenarios. It suggests that the Hubble constant as determined within 70 h(-1) Mpc could be overestimated by similar to 6%, and the local value of Omega may be underestimated by similar to 20%. While the present evidence for a local void is marginal in this data set, the analysis shows that the accumulation of SN Ia distances will soon provide useful constraints on elusive and important aspects of regional cosmic dynamics. C1 Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. RP Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. NR 64 TC 127 Z9 127 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 20 PY 1998 VL 503 IS 2 BP 483 EP 491 DI 10.1086/306015 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700001 ER PT J AU Seljak, U AF Seljak, U TI Cosmography and power spectrum estimation: A unified approach SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; large-scale structure of universe; methods : analytical ID SKY MAPS; RECONSTRUCTION AB We present a unified approach to the problems of reconstruction of large-scale structure distribution in the universe and determination of the underlying power spectrum. These have often been treated as two separate problems, and different analysis techniques have been developed for both. We show that there exists a simple relation between the optimal solutions to the two problems, allowing us to solve for both within the same formalism. This allows one to apply computational techniques developed for one method to the other, which often leads to a significant reduction in the computational time. It also provides a self-consistent treatment of linear reconstruction by first computing the power spectrum from the data themselves. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 21 TC 20 Z9 20 U1 0 U2 0 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 20 PY 1998 VL 503 IS 2 BP 492 EP 501 DI 10.1086/306019 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700002 ER PT J AU Fiore, F Laor, A Elvis, M Nicastro, F Giallongo, E AF Fiore, F Laor, A Elvis, M Nicastro, F Giallongo, E TI The variability properties of X-ray-steep and X-ray-flat quasars SO ASTROPHYSICAL JOURNAL LA English DT Article DE quasars : emission lines; quasars : general; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; OPTICALLY SELECTED QUASARS; ACCRETION DISKS; COMPLETE SAMPLE; SPECTRUM; CONSTRAINTS; ULTRAVIOLET; GALAXY; BUMP AB We have studied the variability of six low-redshift, radio-quiet PG quasars on three timescales (days, weeks, and months) using the ROSAT HRI. The quasars were chosen to lie at the two extreme ends of the ROSAT PSPC spectral index distribution and hence also of the H beta FWHM distribution. The observation strategy has been carefully designed to provide even sampling on these three basic timescales and to provide a uniform sampling among the quasars. We have found clear evidence that the X-ray-steep, narrow-H beta quasars systematically show larger amplitude variations than the X-ray-flat, broad-H beta quasars on timescales from 2 to 20 days. On longer timescales, we do not fmd significant differences between steep and flat quasars, although the statistics are poorer. We suggest that the above correlation between variability properties and spectral steepness can be explained by a scenario in which the X-ray-steep, narrow-line objects are in a higher L/L-Edd state with respect to the X-ray-flat, broad-line objects. We evaluated the power spectrum of PG 1440+356 (the brightest quasar in our sample) between 2 x 10(-7) and similar to 10-3 Hz, where it goes into the noise. The power spectrum is roughly consistent with a 1/f law between 10(-3) and 2 x 10(-6) Hz. Below this frequency it flattens significantly. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron Roma, I-00040 Rome, Italy. SAX Sci Data Ctr, Rome, Italy. Technion Israel Inst Technol, Dept Phys, IL-32000 Haifa, Israel. RP Fiore, F (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Nicastro, Fabrizio/0000-0002-6896-1364; Giallongo, Emanuele/0000-0003-0734-1273; Fiore, Fabrizio/0000-0002-4031-4157 NR 36 TC 37 Z9 37 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP 607 EP 616 DI 10.1086/306031 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700012 ER PT J AU Marzke, RO da Costa, LN Pellegrini, PS Willmer, CNA Geller, MJ AF Marzke, RO da Costa, LN Pellegrini, PS Willmer, CNA Geller, MJ TI The galaxy luminosity function at z <= 0.05: Dependence on morphology SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : luminosity function, mass function; galaxies : structure ID CFA REDSHIFT SURVEY; NUMBER COUNTS; CCD CALIBRATION; MAGNITUDE SCALE; FIELD GALAXIES; POWER SPECTRUM; DEEP SURVEY; EVOLUTION; DENSITY; SAMPLE AB We investigate the dependence of the local galaxy luminosity function on morphology using 5404 galaxies from the recently enlarged Second Southern Sky Redshift Survey (SSRS2). Over the range -22 less than or equal to M-B less than or equal to - 14 (H-0 = 100 km s(-1) Mpc(-1)), the luminosity function of early-type galaxies is well fitted by a Schechter function with parameters M-* = -19.37(-0.11)(+0.10), alpha = -1.00(-0.09)(+0.09), and phi(*) = 4.4 +/- 0.8 x 10(-3) Mpc(-3). The spiral luminosity function is very similar and is well fitted by the parameters M-* = -19.43(-0.08)(+0.08), alpha = -1.11(-0.06)(+0.07), and phi(*) = 8.0 +/- 1.4 x 10(-3) Mpc(-3) over the same range in absolute magnitude. The flat faint end of the early-type luminosity function is consistent with earlier measurements from the CfA Redshift Survey (Marzke et al.) but is significantly steeper than the slope measured in the Stromlo-APM survey (Loveday et al.). Combined with the increased normalization of the overall LF measured from intermediate-redshift surveys, the flat faint-end slope of the E/S0 LF produces no-evolution models that reproduce the deep Hubble Space Telescope (HST) counts of early-type galaxies remarkably well. However, the observed normalization of the SSRS2 LF is consistent with the low value measured in other local redshift surveys. The cause of this lo-redshift anomaly remains unknown. The luminosity function of irregular and peculiar galaxies in the SSRS2 is very steep: M-* -19.78(-0.50)(+0.40) alpha = -1.81(-0.24)(+0.24), and phi(*) = 0.2 +/- 0.08 x 10(-3) Mpc(-3). The steep slope at the faint end is consistent with the LFs measured for Sm-Im galaxies in the CfA survey, UV-selected galaxies (Treyer et al.), star-forming held galaxies (Bromley et al.), and the bluest galaxies in the SSRS2 (Marzke & da Costal. As shown by Driver, Windhorst, & Griffiths, the steep LF reduces the observed excess of faint irregulars over no-evolution predictions but cannot explain it entirely. C1 Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. European So Observ, D-85748 Garching, Germany. CNPq, Observ Nacl, Dept Astron, BR-20921 Rio De Janeiro, Brazil. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Marzke, RO (reprint author), Carnegie Inst Washington Observ, 813 Santa Barbara St, Pasadena, CA 91101 USA. RI da Costa, Luiz Alberto/I-1326-2013 OI da Costa, Luiz Alberto/0000-0002-7731-277X NR 70 TC 199 Z9 200 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP 617 EP 631 DI 10.1086/306011 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700013 ER PT J AU Williams, JP Bergin, EA Caselli, P Myers, PC Plume, R AF Williams, JP Bergin, EA Caselli, P Myers, PC Plume, R TI The ionization fraction in dense molecular gas. I. Low-mass cores SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; ISM : abundances; ISM : clouds; ISM : magnetic fields; ISM : molecules; stars : formation ID INTER-STELLAR CLOUDS; TAURUS DARK CLOUDS; INTERSTELLAR CLOUDS; STAR FORMATION; INFRARED-SPECTROSCOPY; AMBIPOLAR DIFFUSION; CARBON-MONOXIDE; THERMAL BALANCE; CHEMISTRY; DEUTERIUM AB Observations of (CO)-O-18, (HCO+)-C-13, and DCO+ toward 23 low-mass cores are used to constrain the fractional ionization (electron abundance) within them. Chemical models have been run over a wide range of densities, cosmic-ray ionization rates, and elemental depletions, and we find that we can fit 20 of the 23 cores for densities of n(H2) = (1-3) x 10(4) cm(-3), moderate C and O abundance variations, and a cosmic-ray ionization rate of zeta(H2) = 5 x 10(-17) s(-1). The derived ionization fractions lie within the range 10(-7.5) to 10(-6.5), with a median value of x(e,m) = 9 x 10(-8) and typical errors for each individual core equal to a factor of 3. These Values imply that the cores are weakly coupled to the magnetic field and that MHD waves can propagate within them. The ambipolar diffusion timescale is about an order of magnitude greater than the free-fall time, and the cores can be considered to be in quasi-static equilibrium. There is no significant difference between the ionization fraction for cores with and without embedded stars, which suggests that the molecular ionization in cores is primarily governed by cosmic rays alone. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osserv Astrofis Arcetri, I-50125 Florence, Italy. RP Williams, JP (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Williams, Jonathan/B-1643-2009; OI Williams, Jonathan/0000-0001-5058-695X NR 60 TC 126 Z9 126 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP 689 EP 699 DI 10.1086/306034 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700018 ER PT J AU Hillas, AM Akerlof, CW Biller, SD Buckley, JH Carter-Lewis, DA Catanese, M Cawley, MF Fegan, DJ Finley, JP Gaidos, JA Krennrich, F Lamb, RC Lang, MJ Mohanty, G Punch, M Reynolds, PT Rodgers, AJ Rose, HJ Rovero, AC Schubnell, MS Sembroski, GH Vacanti, G Weekes, TC West, M Zweerink, J AF Hillas, AM Akerlof, CW Biller, SD Buckley, JH Carter-Lewis, DA Catanese, M Cawley, MF Fegan, DJ Finley, JP Gaidos, JA Krennrich, F Lamb, RC Lang, MJ Mohanty, G Punch, M Reynolds, PT Rodgers, AJ Rose, HJ Rovero, AC Schubnell, MS Sembroski, GH Vacanti, G Weekes, TC West, M Zweerink, J TI The spectrum of TeV gamma rays from the Crab Nebula SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : observations; ISM : individual (Crab Nebula); ISM : magnetic fields; radiation mechanisms : nonthermal; supernova remnants ID CHERENKOV TELESCOPES; HIGH-ENERGY; PULSAR; MODEL; RADIATION AB The spectrum of gamma rays from the Crab Nebula has been measured in the energy range 500 GeV-8 TeV at the Whipple Observatory by the atmospheric Cerenkov technique. Two methods of analysis that were used to derive spectra, in order to reduce the chance of calibration errors, gave good agreement, as did analysis of observations made with changed equipment several years apart. It is concluded that stable and reliable energy spectra can now be made in the TeV range. The spectrum can be represented in this energy range by the power-law fit, J = (3.20 +/- 0.17 +/- 0.6) x 10(-7) x (E/1 TeV)(-2.49+/-0.06+/-0.04) m(-2) s(-1) TeV-1, or by the following form, which extends much better to the GeV domain: J = (3.25 +/- 0.14 +/- 0.6) x 10(-7)E(-2.44+/-0.06+/-0.04-0.151 log10 E) m(-2) s(-1) TeV-1 (E in TeV). The integral flux above 1 TeV is (2.1 +/- 0.2 +/- 0.3) x 10(-7) m(-2) s(-1). Using the complete spectrum of the Crab Nebula, the spectrum of relativistic electrons is deduced, and the spectrum of the inverse Compton emission that they would generate is in good agreement with the observed gamma-ray flux from 1 GeV to many TeV, if the magnetic field in the region where these scattered photons originate (essentially the X-ray-emitting region, around 0.4 pc from the pulsar) is similar to 16 nT (160 mu G), in reasonable agreement with the held deduced by Aharonian & Atoyan. If the same field strength were present throughout the nebula, there would be no clear need for an additional radiation source in the GeV domain such as has recently been suggested; the results give an indication that the magnetic field is well below the often-assumed equipartition strength (35-60 nT). Further accurate gamma-ray spectral measurements over the range from 1 GeV to tens of TeV have the potential to probe the growth in the magnetic field in the inner region of the nebula. C1 Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Univ Michigan, Randall Lab Phys, Ann Arbor, MI 48109 USA. Harvard Smithsonian Ctr Astrophys, Whipple Observ, Amado, AZ 85645 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. St Patricks Coll, Dept Phys, Maynooth, Kildare, Ireland. Natl Univ Ireland Univ Coll Dublin, Dept Expt Phys, Dublin 4, Ireland. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. CALTECH, Space Sci Lab, Pasadena, CA 91125 USA. European Space Agcy, ESTEC, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. Natl Univ Ireland Univ Coll Galway, Dept Phys, Galway, Ireland. Consejo Nacl Invest Cient & Tecn, Inst Astron & Fis Espacio, RA-1428 Buenos Aires, DF, Argentina. RP Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. OI Punch, Michael/0000-0002-4710-2165; Lang, Mark/0000-0003-4641-4201 NR 48 TC 195 Z9 197 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 20 PY 1998 VL 503 IS 2 BP 744 EP 759 DI 10.1086/306005 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700022 ER PT J AU Spaans, M Neufeld, D Lepp, S Melnick, GJ Stauffer, J AF Spaans, M Neufeld, D Lepp, S Melnick, GJ Stauffer, J TI Search for interstellar water in the translucent molecular cloud toward HD 154368 SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : ISM : lines and bands; ISM : molecules; molecular processes; stars : individual (HD 154368); ultraviolet : ISM ID HIGH-RESOLUTION OBSERVATIONS; DISSOCIATIVE RECOMBINATION; NA-I; ABSORPTION; MODELS; ASSOCIATION; ABUNDANCES; EXTINCTION; HD-154368; RATIOS AB We report an upper limit of 9 x 10(12) cm(-2) on the column density of water in the translucent cloud along the line of sight toward HD 154368. This result is based on a search for the C-X band of water near 1240 Angstrom carried out using the Goddard High-Resolution Spectrograph (GHRS) of the Hubble Space Telescope. Our observational Limit on the water abundance, together with detailed chemical models of translucent clouds and previous measurements of OH along the line of sight, constrains the branching ratio in the dissociative recombination of H3O+ to form water. We find at the 3 sigma level that no more than 30% of dissociative recombinations of H3O+ can lead to H2O. The observed spectrum also yielded high-resolution observations of the Mg II doublet at 1239.9 Angstrom and 1240.4 Angstrom, allowing the velocity structure of the dominant ionization state of magnesium to be studied along the line of sight. The Mg II spectrum is consistent with GHRS observations at lower spectral resolution that were obtained previously but allow an additional velocity component to be identified. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Nevada, Las Vegas, NV 89154 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 37 TC 12 Z9 12 U1 0 U2 0 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 20 PY 1998 VL 503 IS 2 BP 780 EP 784 DI 10.1086/306033 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700024 ER PT J AU Kraemer, KE Jackson, JM Lane, AP AF Kraemer, KE Jackson, JM Lane, AP TI [O I] 63 micron absorption in NGC 6334 SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : ISM : continuum; H II regions; ISM : individual (NGC 6334); stars : formation ID FAR-INFRARED OBSERVATIONS; PHOTODISSOCIATION REGIONS; MOLECULAR CLOUDS; NGC-6334; EMISSION; LINE; SPECTROSCOPY; MODEL; DISK; GAS AB The [O I] 63 mu m transition has been imaged around five far-infrared (FIR) and radio continuum sources in the southern massive star formation region NGC 6334. The [O I] 63 mu m line is found in absorption toward the FIR continuum source NGC 6334V. This is only the second case in which the [O I] 63 mu m line has been seen in absorption against a continuum source. From the depth of the absorption line, the minimum column density of oxygen is calculated to be N(O-0) greater than or similar to 5 x 10(18) cm(-2). This amount of oxygen is consistent with [O I] 63 mu m absorption due to atomic gas in the foreground molecular cloud. The [O I] 63 mu m line is found in emission toward the other four sources observed: NGC 6334, sources A, C, D, and E. Single-component photodissociation region (PDR) models suggest densities of n similar to 10(4) cm(-3) for these sources, based on previously observed [O I] 145 mu m and [C II] 158 mu m intensities. However, unphysically large far-ultraviolet (FUV) fields are implied for three of the sources, particularly for NGC 6334A. Neither one- nor two-component photodissociation region models can explain the anomalously low [O I] 63 mu m intensity toward NGC 6334A nor the absorption toward NGC 6334V. We suggest that self-absorption of the [O I] 63 mu m line, such as has been suggested toward DR 21, is suppressing the observed [O I] 63 mu m intensity. This underestimate leads to an overestimate of the derived FUV field strengths throughout NGC 6334. The discovery of several more star-forming sites in which the [O I] 63 mu m is in absorption or is self-absorbed implies that this line is not always a reliable PDR diagnostic because the PDR models do not treat the radiative transfer through the molecular cloud. C1 Boston Univ, Dept Astron, Boston, MA 02215 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kraemer, KE (reprint author), Boston Univ, Dept Astron, 725 Commonwealth Ave, Boston, MA 02215 USA. OI Kraemer, Kathleen/0000-0002-2626-7155 NR 37 TC 27 Z9 27 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP 785 EP 791 DI 10.1086/306002 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700025 ER PT J AU Smith, RK Dwek, E AF Smith, RK Dwek, E TI Soft X-ray scattering and halos from dust SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; ISM : abundances; novae, cataclysmic variables; stars : individual (Nova Cygni 1992); X-rays : general; X-rays : ISM ID INTERSTELLAR DUST; OPTICAL-PROPERTIES; GRAINS; CARBON; PARTICLES; GRAPHITE; EMISSION AB Small-angle scatterings of X-rays by interstellar dust particles create halos around X-ray sources. The halo intensity and its projected radial distribution around a source can provide important information on the spatial distribution of the dust along the line of sight to the source and on the physical properties of the scattering dust particles. Halos around X-ray point sources have been used by several authors to infer that the scattering dust particles are fluffy in nature, consisting of aggregates of smaller refractory particles with vacuum occupying a significant fraction of their volume. The nature and morphology of interstellar dust particles has recently gained new importance, since huffy, composite dust particles have been suggested as a possible solution to the interstellar carbon "crisis." This crisis results from the discrepancy between the abundance of carbon in the interstellar medium available for creating dust and the significantly larger amount of carbon that must be in dust in order to account for the UV-optical interstellar extinction in the diffuse ISM. Previous studies of X-ray scattering have used the Rayleigh-Gans (RG) approximation to the differential scattering cross section to calculate halo properties. However, the validity of the RG approximation fails for energies below 1 keV. We use the exact Mie solution for the differential scattering cross section and find that, for these energies, the scattering becomes much less efficient than is predicted by the RG approximation. Furthermore, the effects of K and L shell absorption by atoms in the dust become important. The net effect is that the RG approximation systematically and substantially overestimates the intensity of the halo below 1 keV, relative to the Mie solution result. In particular, Mathis and coworkers used the weaker than expected halo intensity observed around Nova Cygni 1992 to conclude that interstellar dust must be fluffy. Using the Mie solution to the scattering intensity and including the effects of absorption, we find that, contrary to the conclusion of Mathis and coworkers, the halo around Nova Cygni 1992 does not require interstellar dust grains to be fluffy in nature and that the data are consistent with scattering from a mixture of bare refractory silicate and carbon grains as well. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, RK (reprint author), Smithsonian Astrophys Observ, High Energy Astrophys Div, 60 Garden St, Cambridge, MA 02138 USA. NR 27 TC 69 Z9 69 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP 831 EP 842 DI 10.1086/306018 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KN UT WOS:000077776700030 ER PT J AU Perna, R Loeb, A AF Perna, R Loeb, A TI X-ray absorption by the hot intergalactic medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE X-rays : ISM ID IONIZATION EQUILIBRIUM; GALAXIES; CLUSTERS; ELEMENTS; EINSTEIN AB The current census of observed baryons in the local universe is still missing a significant fraction of them according to standard big bang nucleosynthesis. Numerical simulations predict that most of the missing baryons are in a hot intergalactic medium, which is difficult to observe through its X-ray emission or the Sunyaev-Zeldovich effect. We show that the next generation of X-ray satellites will be able to detect this gas through the X-ray absorption lines imprinted by its highly ionized metals on the spectrum of a background quasar. For the metallicity typically found in intracluster gas, up to 70% of the baryons produce O VIII absorption lines with an equivalent width greater than or similar to 0.1 eV. The spectrum of any high-redshift quasar is expected to show several such lines per unit redshift due to intervening gaseous hares of galaxy groups. These lines will be detectable at a signal-to-noise ratio of greater than or similar to 5 after a day of integration with the future Constellation-X telescope for any of the several tens of the brightest quasars across the sky. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Perna, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 26 TC 35 Z9 35 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP L135 EP L138 DI 10.1086/311544 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KQ UT WOS:000077777000008 ER PT J AU Schachter, JF Fiore, F Elvis, M Mathur, S Wilson, AS Morse, JA Awaki, H Iwasawa, K AF Schachter, JF Fiore, F Elvis, M Mathur, S Wilson, AS Morse, JA Awaki, H Iwasawa, K TI NGC 7582: The prototype narrow-line X-ray galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : general; galaxies : active; galaxies : Seyfert; X-rays : galaxies ID ROSAT SERENDIPITY SURVEY; SEYFERT-GALAXIES; ASCA OBSERVATIONS; ACTIVE GALAXIES; EMISSION; CLASSIFICATION; CONSTRAINTS; NGC-4151; FIELDS; AGN AB NGC 7582 is a candidate prototype of the narrow line X-ray galaxies (NLXGs) found in deep X-ray surveys. An ASCA observation shows the hard (>3 keV) X-ray continuum of NGC 7582 drops 40% in similar to 6 ks, implying an active galactic nucleus (AGN), while the soft band (<3 keV) does not drop in concert with the hard continuum, requiring a separate component. The X-ray spectrum of NGC 7582 also shows a clear 0.5-2 keV soft (kT = 0.8(-0.3)(+0.9) keV or Gamma = 2.4 +/- 0.6; L-x = 6 x 10(40) ergs s(-1)) low-energy component, in addition to a heavily absorbed [N-H = (6 +/- 2) x 10(22) cm(-2)] and variable 2-10 keV power law [Gamma = 0.7(-0.4)(+0.3); L-x = (1.7-2.3) x 10(42) ergs s(-1)]. This is one of the flattest 2-10 keV slopes in any AGN observed with ASCA. (The ROSAT HRI image of NGC 7582 further suggests extent to the SE.) These observations make it clear that the hard X-ray emission of NGC 7582, the most "narrow-line" of the NLXGs, is associated with an AGN. The strong suggestion is that all NLXGs are obscured AGNs, as hypothesized to explain the X-ray background spectral paradox. The separate soft X-ray component makes NGC 7582 land by extension other NLXGs) detectable as a ROSAT source. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Maryland, Dept Astron, College Pk, MD 21218 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Kyoto Univ, Fac Sci, Dept Phys, Sakyo Ku, Kyoto 60601, Japan. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Schachter, JF (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Fiore, Fabrizio/0000-0002-4031-4157 NR 41 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP L123 EP L126 DI 10.1086/311537 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KQ UT WOS:000077777000005 ER PT J AU Stanek, KZ Garnavich, PM AF Stanek, KZ Garnavich, PM TI Distance to M31 with the Hubble Space Telescope and Hipparcos red clump stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : distances and redshifts; galaxies : individual (M31); Galaxy : center; solar system : general; stars : horizontal-branch ID COLOR-MAGNITUDE DIAGRAMS; I-BAND OBSERVATIONS; HST V-BAND; GALACTIC BAR; GLOBULAR-CLUSTERS; BAADES-WINDOW; POPULATIONS; CALIBRATION; BULGE; HALO AB Following the approach by Paczynski & Stanek, we compare the red clump stars with parallaxes known to better than 10% in the Hipparcos catalog with the red clump stars observed in three fields in M31 using the Hubble Space Telescope. There are similar to 600 and similar to 6300 such stars in the two data sets, respectively. The local red clump luminosity function is well represented by a Gaussian with the peak at M-l,M-m = -0.23 and the dispersion sigma(RC) approximate to 0.2 mag. This allows a single-step determination of the distance modulus to M31, mu(0,M31) = 24.471 +/- 0.035 +/- 0.045 mag (statistical plus systematic error), and the corresponding distance, R-M31 = 784 +/-. 13 +/- 17 kpc. The number of red clump stars is large enough that the formal statistical error in the distance is only less than or similar to 2%. We also correct the treatment of the local interstellar extinction by Paczynski & Stanek, and we obtain the Galactocentric distance modulus, mu(0,GC) = 14.57 +/- 0.04 +/- 0.04 mag (statistical plus systematic error), and the corresponding Galactocentric distance, R-0 = 8.2 +/- 0.15 +/- 0.15 kpc. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Stanek, KZ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 20, Cambridge, MA 02138 USA. NR 31 TC 233 Z9 236 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1998 VL 503 IS 2 BP L131 EP L134 DI 10.1086/311539 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KQ UT WOS:000077777000007 ER PT J AU Jordan, HL Howard, J Barr, MC Kennedy-Stoskopf, S Levy, JK Tompkins, WA AF Jordan, HL Howard, J Barr, MC Kennedy-Stoskopf, S Levy, JK Tompkins, WA TI Feline immunodeficiency virus is shed in semen from experimentally and naturally infected cats SO AIDS RESEARCH AND HUMAN RETROVIRUSES LA English DT Article ID DOMESTIC CATS; SEXUAL TRANSMISSION; SEMINAL PLASMA; UNITED-STATES; TYPE-1; HIV-1; AIDS; INSEMINATION; DISEASE; MODEL AB Although a laboratory isolate of feline immunodeficiency virus (FIV), FIV-NCSU(1), has been transmitted by artificial insemination in domestic cats, transmission by naturally infected males during mating has not been reported. In order to determine whether virus shedding in semen is unique to the NCSU(1) isolate, we analyzed electroejaculates from four specific-pathogen-free males infected with another laboratory strain, FIV-Petaluma, and eight random source males with naturally acquired infections. Seminal cell lysates from the cats infected with the Petaluma isolate were screened by nested polymerase chain reaction amplification for FIV gag DNA, Seminal cells and seminal plasma from these FIV-Petaluma cats were further analyzed for the presence of virus by cocultivation with a feline CD(4+) T cell line and Crandell feline kidney cells. Electroejaculates from the naturally infected cats were cocultivated with the T cell line. Our results demonstrated that cell-free FIV was present in seminal plasma from two FIV-Petaluma cats and two naturally infected cats. Cell-associated seminal virus was detected in all of the FIV-Petaluma infected cats and one naturally infected cat. Secretion of viral gag p26 antigen, an indication of active viral replication, was evident in cocultures containing motile sperm purified by a swim-up procedure from a FIV-Petaluma cat. These results confirm that FIV shedding in semen is not restricted to a specific virus isolate, Furthermore, swim-up sperm from FIV-infected cats may be infectious in vitro. C1 N Carolina State Univ, Pylon Res Labs, Coll Vet Med, Raleigh, NC 27606 USA. Harvard Univ, Sch Med, Beth Israel Deaconess Med Ctr, Div Viral Pathogenesis, Boston, MA 02215 USA. Smithsonian Inst, Natl Zool Pk, Washington, DC 20008 USA. Scripps Res Inst, La Jolla, CA 92307 USA. Univ Florida, Coll Vet Med, Gainesville, FL 32610 USA. RP Tompkins, WA (reprint author), N Carolina State Univ, Pylon Res Labs, Coll Vet Med, 617 Hutten St, Raleigh, NC 27606 USA. FU NCRR NIH HHS [7 K01RR00109-02] NR 44 TC 19 Z9 19 U1 1 U2 1 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 0889-2229 J9 AIDS RES HUM RETROV JI Aids Res. Hum. Retrovir. PD AUG 10 PY 1998 VL 14 IS 12 BP 1087 EP 1092 DI 10.1089/aid.1998.14.1087 PG 6 WC Immunology; Infectious Diseases; Virology SC Immunology; Infectious Diseases; Virology GA 112VP UT WOS:000075515600009 PM 9718125 ER PT J AU Bouvier, J Stauffer, JR Martin, EL Navascues, DBY Wallace, B Bejar, VJS AF Bouvier, J Stauffer, JR Martin, EL Navascues, DBY Wallace, B Bejar, VJS TI Brown dwarfs and very low-mass stars in the Pleiades cluster: a deep wide-field imaging survey SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : low-mass, brown dwarfs; stars : luminosity function, mass function; Galaxy : open clusters and associations :; individual : Pleiades = Melotte 22; Galaxy : open clusters and associations : general ID RADIAL-VELOCITIES; FAINT MEMBERS; SEARCH; CANDIDATES; LITHIUM; HYADES AB We have performed a deep, wide-field imaging survey of the Pleiades cluster (Melotte 22) in the R and I-bands to search for very low-mass stars and brown dwarfs. The survey extends over similar to 2.5 square degrees around the cluster's center down to a similar to 90% completeness limit of R similar to 23 and I similar to 22. We find 26 objects whose location in the (I, R-I) color-magnitude diagram is consistent with them being Pleiades members. Of these, 17 have extremely red (R-I) colors and low I luminosity, which make them prime brown dwarf candidates. We present the luminosity function of the Pleiades cluster down to M(I)similar to 15. Using current-generation theoretical models, we compute the mass of the brown dwarf candidates which is found to range from the hydrogen-burning limit down to about 0.045 M.. Based on these results, a preliminary estimate of the Pleiades mass function is presented. While the stellar portion of the Pleiades mass function is well approximated by the log-normal IMF of Miller & Scale (1979), the substellar part of it is found to be slightly higher than predicted by Miller & Scale's IMF In a log-log plot, the IMF is found to be still rising in the substellar domain, with a slope consistent with dN/dM similar to M-0.6 if a power-law functional form is assumed. We estimate a total of about 250 objects below the hydrogen burning mass limit in the Pleiades which nevertheless make up only a few per cent of the mass of the cluster. C1 Univ Grenoble 1, Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Tenerife, Spain. Univ Victoria, Victoria, BC V8W 2Y2, Canada. RP Univ Grenoble 1, Observ Grenoble, Astrophys Lab, BP 53, F-38041 Grenoble 9, France. EM jbouvier@laog.obs.ujf-grenoble.fr RI Barrado Navascues, David/C-1439-2017 OI Barrado Navascues, David/0000-0002-5971-9242 NR 54 TC 182 Z9 182 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 AUG 10 PY 1998 VL 336 IS 2 BP 490 EP 502 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 110RQ UT WOS:000075394500013 ER PT J AU Bartelmann, M Loeb, A AF Bartelmann, M Loeb, A TI Effects of disks on gravitational lensing by spiral galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; galaxies : spiral; gravitational lensing; quasars : absorption lines ID LYMAN-ALPHA SYSTEMS; LUMINOSITY FUNCTION; SURFACE-BRIGHTNESS; MASS FLUCTUATIONS; EINSTEIN RING; ABSORPTION; EVOLUTION; DUST; STATISTICS; POPULATION AB Gravitational lensing of a quasar by a spiral galaxy should often be accompanied by damped Ly alpha absorption and dust extinction due to the intervening gaseous disk. In nearly edge-on configurations, the surface mass density of the gas and stars in the disk could by itself split the quasar image and contribute significantly to the overall lensing cross section. We calculate the lensing probability of a disk-plus-halo mass model for spiral galaxies, including the cosmic evolution of the lens parameters. A considerable fraction of the lens systems produce two images with subarcsecond separation, straddling a nearly edge-on disk. Because of that, extinction by dust together with observational selection effects (involving a minimum separation and a maximum flux ratio for the lensed images) suppress the detection efficiency of spiral lenses in optical wave bands by at least an order of magnitude. The missing lenses could be recovered in radio surveys. In modifying the statistics of damped Lya absorbers, the effect of extinction dominates over the magnification bias due to lensing. C1 Max Planck Inst Astrophys, D-85740 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Bartelmann, M (reprint author), Max Planck Inst Astrophys, POB 1523, D-85740 Garching, Germany. RI Bartelmann, Matthias/A-5336-2014 NR 67 TC 25 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1998 VL 503 IS 1 BP 48 EP 60 DI 10.1086/305989 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KK UT WOS:000077776400004 ER PT J AU Markevitch, M Forman, WR Sarazin, CL Vikhlinin, A AF Markevitch, M Forman, WR Sarazin, CL Vikhlinin, A TI The temperature structure of 30 nearby clusters observed with ASCA: Similarity of temperature profiles SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : clusters : general; hydrodynamics; X-rays : galaxies ID X-RAY OBSERVATIONS; GALAXY CLUSTERS; COOLING FLOWS; DARK-MATTER; INTRACLUSTER GAS; EMITTING GAS; COMA CLUSTER; ROSAT; MAP; EVOLUTION AB We present an analysis of ASCA spatially resolved spectroscopic data for a nearly complete sample of bright clusters with redshifts between 0.04 and 0.09. Together with several clusters analyzed elsewhere using the same method, this sample consists of 30 objects with T-e greater than or equal to 3.5 keV for which we obtained projected temperature profiles and, when possible, crude two-dimensional temperature maps. The clusters are A85, A119, A399, A401, A478, A644, A754, A780, A1650, A1651, A1795, A2029, A2065, A2142, A2256, A2319, A2597, A2657, A3112, A3266, A3376, A3391, A3395, A3558, A3571, A3667, A4059, Cygnus A, MKW 3S, and Triangulum Australis. All clusters, with the possible exception of a few with insufficiently accurate data, are found to be nonisothermal with spatial temperature variations (apart from cooling flows) by a factor of 1.3-2. ASCA temperature maps for many clusters reveal merger shocks. The most notable of these are A754, A2065, A3558, A3667, and Cygnus A; merging can also be inferred with lower confidence from the A85, A119, and A2657 temperature maps and from the A3395 and Triangulum Australis entropy maps. About one-half of the sample show signs of merging; in about 60% of the sample, we detect cooling flows. Nearly all clusters show a significant radial temperature decline at large radii. For a typical 7 keV cluster, the observed temperature decline between 1 and 6 X-ray core radii (0.15 and 0.9 h(-1) Mpc) can be approximately quantified by a polytropic index of 1.2-1.3. Assuming such a polytropic temperature profile and hydrostatic equilibrium, the gravitating masses within 1 and within 6 core radii are approximately 1.35 and 0.7 times the isothermal beta-model estimates, respectively. Most interestingly, we find that temperature profiles, excluding those for the most asymmetric clusters, appear remarkably similar when the temperature is plotted against the radius in units of the estimated virial radius. We compare the composite temperature profile to a host of published hydrodynamic simulations. The observed profiles appear steeper than predictions of most simulations. The predictions for Omega = 1 cosmological models are most discrepant, while models with low Omega are closer to our data. We note, however, that at least two high-resolution Omega = 1 simulations produced clusters with temperature profiles similar to or steeper than those observed. Our results thus provide a new constraint for adjusting numerical simulations and, potentially, discriminating among models of cluster formation. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Russian Acad Sci, Space Res Inst, Moscow 117901, Russia. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. RP Markevitch, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 89 TC 404 Z9 405 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1998 VL 503 IS 1 BP 77 EP 96 DI 10.1086/305976 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KK UT WOS:000077776400007 ER PT J AU Siemiginowska, A Bechtold, J Aldcroft, TL McLeod, KK Keeton, CR AF Siemiginowska, A Bechtold, J Aldcroft, TL McLeod, KK Keeton, CR TI Q1208+1011: Search for the lensing galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; quasars : absorption lines; quasars : individual (Q1208+1101) ID REDSHIFT 3.8; EVOLUTION; ABSORPTION; SPECTROSCOPY; STATISTICS; TELESCOPE; SPECTRUM; LENSES; QUASAR; QSO AB We present a high-resolution spectrum of the high-redshift, lensed quasar Q1208 + 1101, obtained with the echellette spectrograph on the Multiple Mirror Telescope. We examine the new and published spectra and provide an updated list of high-confidence metal-line absorption systems at z = 1.1349, 2.8626, 2.9118, 2.9136, and 2.9149. Combining this with a simple model of the gravitational lens system allows us to constrain the possible lens redshifts. The high-redshift (z > 2.5) and low-redshift (z < 0.4) candidates can be ruled out with high confidence. The current spectra effectively probe about 40% of the redshift range in which the lens is expected. In that range, there is only one known metal-line absorption system, an Mg II absorber at z = 1.1349. We consider the possibility that this system is the lensing galaxy and discuss the implied parameters of the galaxy. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Wellesley Coll, Whitin Obser, Wellesley, MA 02181 USA. RP Siemiginowska, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS-70, Cambridge, MA 02138 USA. EM asiemiginowska@cfa.harvard.edu; jbechtold@as.arizona.edu; taldcroft@cfa.harvard.edu; kmcleod@wellesley.edu; ckeeton@cfa.harvard.edu NR 28 TC 7 Z9 7 U1 0 U2 0 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 1998 VL 503 IS 1 BP 118 EP 124 DI 10.1086/305983 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KK UT WOS:000077776400010 ER PT J AU Kashyap, V Drake, JJ AF Kashyap, V Drake, JJ TI Markov-chain Monte Carlo reconstruction of emission measure distributions: Application to solar extreme-ultraviolet spectra SO ASTROPHYSICAL JOURNAL LA English DT Review DE atomic processes; radiative transfer; Sun : corona; Sun : UV radiation ID WAVE COLLISION STRENGTHS; STELLAR CORONAL ABUNDANCES; ELECTRON-IMPACT EXCITATION; FINE-STRUCTURE TRANSITIONS; BE-LIKE IONS; N = 1; LINE-INTENSITIES; ATOMIC DATA; TEMPERATURE STRUCTURE; OSCILLATOR-STRENGTHS AB We have developed a new method for the reconstruction of differential emission measure distributions based on a Metropolis Markov-chain Monte Carlo (MCMC[M]) method. This technique allows us to (1) relax nonphysical smoothness constraints generally imposed on DEMs, (2) determine confidence bounds on the computed values, and (3) include extra information in the form of upper limits. Using the MCMC[M] algorithm, we reanalyze extreme ultraviolet spectral line fluxes obtained from Solar Extreme Ultraviolet Rocket Telescope and Spectrograph observations by Brosius et al. to obtain differential emission measure (DEM) distributions for active and quiet regions on the Sun. Both active- and quiet-region DEMs show a probable minimum near log T approximate to 5.6; the quiet-region DEM drops off beyond log T = 6.4, while the active-region DEM does not show evidence of a significant downturn even at log T = 7. The most striking aspect of our results is that the latter also shows several sharp peaks (of width similar to 0.1 dex), notably at log T = 6 and 6.3, and a broad feature, beyond log T = 6.5. We also explore the limitations on DEM reconstruction imposed by imperfect atomic data, choice of spectral lines, uncertainties in abundances, and other systematic errors. Within these limitations, we discuss the derived emission measure distribution and comment on its implications to coronal structure. We conclude that calculation of uncertainties on the DEM are crucial in the interpretation of structure seen in reconstructions. Further, a careful selection of the spectral lines used to infer the DEM is needed in order to avoid "artificially" generating structure in the DEM. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM kashyap@head-cfa.harvard.edu; jdrake@head-cfa.harvard.edu NR 109 TC 122 Z9 122 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 AUG 10 PY 1998 VL 503 IS 1 BP 450 EP 466 DI 10.1086/305964 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KK UT WOS:000077776400043 ER PT J AU Jayawardhana, R Fisher, S Hartmann, L Telesco, C Pina, R Fazio, G AF Jayawardhana, R Fisher, S Hartmann, L Telesco, C Pina, R Fazio, G TI A dust disk surrounding the Young A star HR 4796a SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; circumstellar matter; stars : formation; stars : pre-main-sequence ID BETA-PICTORIS; CIRCUMSTELLAR DISK; ACCRETION DISKS; EVOLUTION; HR-4796; PLANETS; MODELS; DEBRIS; CLOUDS AB We report the codiscovery of the spatially resolved dust disk of the Vega-like star HR 4796A. Images of the thermal dust emission at lambda = 18 mu m show an elongated structure approximately 200 AU in diameter surrounding the central A0V star. The position angle of the disk (30 degrees +/- 10 degrees) is consistent to the position angle of the M companion star (225 degrees), suggesting that the disk-binary system is being seen nearly along its orbital plane. The surface brightness distribution of the disk is consistent with the presence of an inner disk hole of approximately 50 AU radius, as was originally suggested by Jura et al. on the basis of the infrared spectrum. HR 4796 is a unique system among the Vega-like or beta Pictoris stars in that the hi star companion (a weak-emission T Tauri star) shows that the system is relatively young, similar to 8 +/- 3 Myr. The inner disk hole may provide evidence for coagulation of dust into larger bodies on a timescale similar to that suggested for planet formation in the solar system. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. RP Jayawardhana, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM rjayawardhana@cfa.harvard.edu; telesco@astro.ufl.edu NR 30 TC 125 Z9 125 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1998 VL 503 IS 1 BP L79 EP L82 DI 10.1086/311524 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KL UT WOS:000077776500019 ER PT J AU Loeb, A Perna, R AF Loeb, A Perna, R TI Are H I supershells the remnants of gamma-ray bursts? SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; gamma rays : bursts; ISM : bubbles ID SUPERNOVA-REMNANTS; OB ASSOCIATIONS; STAR-FORMATION; BLACK-HOLES; EVOLUTION; AFTERGLOW; GALAXIES; MODELS AB Gamma-ray bursts (GRBs) are thought to originate at cosmological distances from the most powerful explosions in the universe. If GRBs are not beamed, then the distribution of their number as a function of gamma-ray flux implies that they occur once per similar to(0.3-40) million pears per bright galaxy and that they deposit greater than or similar to 10(53) ergs into their surrounding interstellar medium. The blast wave generated by a GRB explosion would be washed out by interstellar turbulence only after tens of millions of years when it finally slows down to a velocity of similar to 10 km s(-1). This rather long lifetime implies that there could be up to several tens of active GRB remnants in each galaxy at any given time. For many years, radio observations have revealed the enigmatic presence of expanding neutral-hydrogen (H I) supershells of near-kiloparsec radius in the Milky Way and in other nearby galaxies. The properties of some supershells cannot be easily explained in terms of conventional sources such as stellar winds or supernova explosions. However, the inferred energy and frequency of the explosions required to produce most of the observed supershells agree with the above GRB parameters. More careful observations and analysis might reveal which fraction of these supershells are GRB remnants. We show that if this link is established, the data on H I supershells can be used to constrain the energy output, the rate per galaxy, the beaming factor, and the environment of GRB sources in the universe. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 28 TC 67 Z9 71 U1 0 U2 0 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 1998 VL 503 IS 1 BP L35 EP L37 DI 10.1086/311536 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KL UT WOS:000077776500009 ER PT J AU Mathur, S Wilkes, B Elvis, M AF Mathur, S Wilkes, B Elvis, M TI Discovery of associated absorption lines in an X-ray warm absorber: Hubble Space Telescope observations of PG 1114+435 SO ASTROPHYSICAL JOURNAL LA English DT Article DE quasars : absorption lines; quasars : individual (PG 1114+445); ultraviolet : galaxies ID ULTRAVIOLET; NGC-5548; NUCLEI; QUASAR AB The unified picture of X-ray/UV absorbers offers a unique opportunity to probe the nuclear environment of active galactic nuclei. To test the unified absorber scenario and to understand the physical properties of the absorber, we obtained the first UV spectrum of PG 1114+445 using the Hubble Space Telescope (HST) Faint Object Spectrograph. PG 1114+445 is known to have an X-ray ionized ("warm") absorber, so that UV absorption is predicted. The HST spectrum clearly shows strong UV absorption lines due to Ly alpha, C IV, and N V, blueshifted by similar to 530 km s(-1) with respect to the quasar redshift. Since both X-ray and UV absorbers an rare in radio-quiet quasars, these observations argue strongly that the X-ray and UV absorbers are closely physically related, perhaps identical. We place constraints on the parameters of the absorber and conclude that the mass outflow rate is comparable to the accretion rate in PG 1114+445. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mathur, S (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Wilkes, Belinda/0000-0003-1809-2364 NR 19 TC 26 Z9 26 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1998 VL 503 IS 1 BP L23 EP L26 DI 10.1086/311520 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KL UT WOS:000077776500006 ER PT J AU Mediavilla, E Arribas, S Del Burgo, C Oscoz, A Serra-Ricart, M Alcalde, D Falco, EE Goicoechea, LJ Garcia-Lorenzo, B Buitrago, J AF Mediavilla, E Arribas, S Del Burgo, C Oscoz, A Serra-Ricart, M Alcalde, D Falco, EE Goicoechea, LJ Garcia-Lorenzo, B Buitrago, J TI Two-dimensional spectroscopy reveals an arc of extended emission in the gravitational lens system Q2237+0305 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; quasars : individual (Q2237+0305); techniques : spectroscopic ID SPATIALLY RESOLVED SPECTROSCOPY; EINSTEIN-CROSS; C-IV; FIELD; TELESCOPE; MODELS; GALAXY; SPECTROGRAPH; REGION; ALPHA AB We present two-dimensional spectroscopy of the gravitational lens system Q2237+0305 (Einstein Cross) obtained with the INTEGRAL fiber system in subarcsecond seeing conditions. The four components of the system appear clearly separated in the continuum intensity maps. However, the intensity map of the C III] lambda 1909 line exhibits an are of extended emission connecting the A, D, and B components. This result can be explained if, as is usually assumed, the continuum arises from a compact source less than or similar to 0.05 pc in extent in the nucleus of the object while the line emission comes from a much larger region. A lens model fitted to the positions of the four compact images also accounts for the are morphology. In the framework of this model, the region generating the C III] lambda 1909 emission would have dimensions of about 400 h(-1) pc across. We interpret the observed are as a gravitational lens image of the extended narrow line region of the source. C1 Inst Astrofis Canarias, E-38200 La Laguna, Tennerife, Spain. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cantabria, Dept Fis Moderna, E-39005 Santander, Spain. RP Mediavilla, E (reprint author), Inst Astrofis Canarias, E-38200 La Laguna, Tennerife, Spain. RI Garcia-Lorenzo, Maria Begona/E-7011-2010 OI Garcia-Lorenzo, Maria Begona/0000-0002-7228-7173 NR 29 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1998 VL 503 IS 1 BP L27 EP L30 DI 10.1086/311533 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KL UT WOS:000077776500007 ER PT J AU Wood, JA AF Wood, JA TI Meteoritic evidence for the infall of large interstellar dust aggregates during the formation of the solar system SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; solar system : formation ID HIBONITE INCLUSIONS; NEBULA; ALLENDE; GRAINS; CHONDRULES; CHONDRITES; OXYGEN; ORIGIN; AL-26; HAL AB The presence of the short-lived radionuclide Al-26 in some of the refractory inclusions of chondritic meteorites but not in others appears to mean that the substance of the Al-26-free inclusions was brought together in the presolar interstellar medium, before the astrophysical event occurred that synthesized solar system Al-26. The Al-26-free inclusions can be understood as evaporation residues that formed from presolar just aggregations when they were intensely heated by gas drag as they fell into the solar nebula during the collapse phase of solar system formation. The inclusions containing Al-26 were formed from dust that had been seeded with that nuclide prior to aggregation and thermal processing. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Wood, JA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 34 TC 26 Z9 26 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1998 VL 503 IS 1 BP L101 EP L104 DI 10.1086/311517 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KL UT WOS:000077776500023 ER PT J AU Koga, T Backwell, PRY Jennions, MD Christy, JH AF Koga, T Backwell, PRY Jennions, MD Christy, JH TI Elevated predation risk changes mating behaviour and courtship in a fiddler crab SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE fiddler crabs; female choice; mating tactics; predation; sexual selection; Uca ID UCA-BEEBEI; MATE CHOICE; POECILIA-RETICULATA; FEMALE CHOICE; PUGILATOR; LEKKING; SYSTEM AB The fiddler crab, Uca beebei, lives in individually defended burrows, in mixed-sex colonies on intertidal mud flats. Avian predation is common, especially of crabs unable to escape into burrows. Mating pairs form in two ways. Females either mate on the surface at their burrow entrance ('surface mating') or leave their own burrow and sequentially enter and leave ('sample') courting males' burrows, before staying in one to mate underground ('burrow mating'). We tested whether perceived predation risk affects the relative frequency of these mating modes. We first observed mating under natural levels of predation during one biweekly, semi-lunar cycle. We then experimentally increased the perceived predation risk by attracting grackles (Quiscalus mexicanus) to each half of the study site in two successive biweekly cycles. In each experimental cycle, crabs were significantly less likely to mate on the side with more birds. Moreover, on the side with elevated predation risk, the number of females leaving burrows to sample was greatly reduced relative to the number of females that surface-mated. Males waved less and built fewer mud pillars, which attract females, when birds were present. We discuss several plausible proximate explanations for these results and the effect of changes in predation regime on sexual selection. C1 Kyushu Univ, Fac Sci, Dept Biol, Hakazaki, Japan. Smithsonian Trop Res Inst, Balboa, Ancon, Panama. RP Jennions, MD (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. EM gam128@gamboa.si.edu RI Jennions, Michael/C-7560-2009; Backwell, Patricia/C-8883-2009 OI Jennions, Michael/0000-0001-9221-2788; NR 31 TC 97 Z9 99 U1 6 U2 38 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 AUG 7 PY 1998 VL 265 IS 1404 BP 1385 EP 1390 PG 6 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA 113HA UT WOS:000075543600003 ER PT J AU Oliver, R Ballester, JL Baudin, F AF Oliver, R Ballester, JL Baudin, F TI Emergence of magnetic flux on the Sun as the cause of a 158-day periodicity in sunspot areas SO NATURE LA English DT Article ID SOLAR-FLARES; FUNDAMENTAL PERIOD; 154-DAY; COMPLEX; 155-DAY AB The temporal behaviour of solar activity (as manifested in sunspots) has long been debated. The 11-year periodicity in the total number of sunspots is well established observationally, as is a periodicity of 152-158 days in the occurrence of high-energy solar flares that was seen during cycle 21 (refs 1-7). The cause of the latter periodicity is not clear, although several mechanisms have been proposed(8-10). Here we report a time-frequency analysis, using the wavelet technique, of sunspot areas between 1874 and 1993, which reveals a 158-day periodicity coincident with that of energetic solar flares. The signature of this periodicity is strongest in cycle 19, which was the most intense cycle of the century. The periodicity disappears after cycle 21. The analysis shows that the 158-day periodicity in both high-energy solar flares and sunspots is related to a periodic emergence of magnetic flux which only appears near the maxima of some solar cycles. C1 Univ Illes Balears, Dept Fis, E-07071 Palma de Mallorca, Spain. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Ballester, JL (reprint author), Univ Illes Balears, Dept Fis, E-07071 Palma de Mallorca, Spain. EM dfsjlb0@ps.uib.es RI Ballester, Jose /A-2637-2011; Oliver, Ramon/K-1841-2014 OI Ballester, Jose /0000-0001-8921-9225; Oliver, Ramon/0000-0003-4162-7240 NR 23 TC 78 Z9 81 U1 0 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 AUG 6 PY 1998 VL 394 IS 6693 BP 552 EP 553 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 107YN UT WOS:000075238700038 ER PT J AU Glenn, TC Dessauer, HC Braun, MJ AF Glenn, TC Dessauer, HC Braun, MJ TI Characterization of microsatellite DNA loci in American alligators SO COPEIA LA English DT Article ID POPULATION-STRUCTURE; GENETIC-VARIABILITY; F-STATISTICS; SEQUENCES; MARKERS; CONSERVATION; DYNAMICS; PROTOCOL; GENOME AB Microsatellite loci of American alligators were identified from small insert DNA libraries. The average length of microsatellites (18.4 repeats) was similar to that observed in mammals. Polymerase chain reaction (PCR) primers were developed and tested for 20 microsatellite loci that contained at least 10 uninterrupted AC or AG repeats. Genotypes for the 15 loci that could be scored readily were obtained for alligators from Louisiana and Florida. Eleven of the 15 loci were polymorphic. For the polymorphic loci, the number of alleles per locus ranged from 4-17 (average = 8.5), and observed heterozygosity within populations ranged from 0.231-0.865 (average = 0.466). Heterozygosity of these loci is almost 20 times higher than values obtained using isozymes. Populations from Louisiana and Florida differed substantially at these loci (overall F-ST = 0.137, theta(P) = 0.239, and R-ST = 0.387). The PCR primers also produced single amplicons from species of Alligatoridae, Gavialidae, and Crocodilidae, indicating that they may be useful for genetic studies in other crocodilians. C1 Smithsonian Inst, Lab Mol Systemat, Washington, DC 20560 USA. Louisiana State Univ, Dept Biochem, New Orleans, LA 70119 USA. RP Glenn, TC (reprint author), Univ S Carolina, Dept Biol Sci, Columbia, SC 29208 USA. EM Travis.Glenn@sc.edu RI Glenn, Travis/A-2390-2008 NR 43 TC 47 Z9 49 U1 2 U2 4 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS BUSINESS OFFICE PI CARBONDALE PA SOUTHERN ILLINOIS UNIV, DEPT ZOOLOGY, CARBONDALE, IL 62901-6501 USA SN 0045-8511 J9 COPEIA JI Copeia PD AUG 3 PY 1998 IS 3 BP 591 EP 601 DI 10.2307/1447789 PG 11 WC Zoology SC Zoology GA 109WU UT WOS:000075348000005 ER PT J AU Armbruster, JW AF Armbruster, JW TI Phylogenetic relationships of the suckermouth armored catfishes of the Rhinelepis group (Loricariidae : Hypostominae) SO COPEIA LA English DT Article AB The loricariid catfish genera Pogonopoma, Pogonopomoides, Pseudorineleis, aud Rhi nelepis form a monophyletic clade within the subfamily Hypostominae. Phylogenetic analysis of morphologicaI characters reveals the following. relationships: (Pseudorinelepis + (Rhinelepis + (Pogonopoma + Pogonopomoides))). These nodes are strongly supported with several synapomorphies, and each genus is redescribed and diagnosed. Phylogenetic analysis revealed a split between the Amazonian genus (Pseudorinelepis) and the remainder of the genera which occur in southeastern Brazil. C1 Illinois Nat Hist Survey, Champaign, IL 61820 USA. RP Armbruster, JW (reprint author), Smithsonian Inst, Div Fishes, Natl Museum Nat Hist, Washington, DC 20560 USA. EM armbruster.jonathan@nmnh.si.edu NR 19 TC 18 Z9 22 U1 1 U2 2 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS BUSINESS OFFICE PI CARBONDALE PA SOUTHERN ILLINOIS UNIV, DEPT ZOOLOGY, CARBONDALE, IL 62901-6501 USA SN 0045-8511 J9 COPEIA JI Copeia PD AUG 3 PY 1998 IS 3 BP 620 EP 636 DI 10.2307/1447792 PG 17 WC Zoology SC Zoology GA 109WU UT WOS:000075348000008 ER PT J AU Armbruster, JW AF Armbruster, JW TI Modifications of the digestive tract for holding air in loricariid and scoloplacid catfishes SO COPEIA LA English DT Article ID RESPIRATORY MODE; FISHES; RHINELEPIS AB Loricariid catfishes have evolved several modifications of the digestive tract that appear to function as accessory respiratory organs or hydrostatic organs. Adaptations include an enlarged stomach in Pterygoplichthys, Liposarcus, Glyptoperichthys, Hemiancistrus annectens, Hemiancistrus maracaiboensis, Hypostomus panamensis, and Lithoxus; a U-shaped diverticulum in Rhinelepis, Pseudorinelepis, Pogonopoma, and Pogonopomoides; and a ringlike diverticulum in Otocinclus. Scoloplacids, closely related to loricariids, have enlarged, clear, air-filled stomachs similar to that of Lithoxus. The ability to breathe air in Otocinclus was confirmed; the ability of Lithoxus and Scoloplax to breathe air is inferred from morphology. The diverticula of Pogonopomoides and Pogonopoma are similar to swim bladders and may be used as hydrostatic organs. The various modifications of the stomach probably represent characters that define monophyletic clades. The ovaries of Lithoxus were also examined and were shown to have very few (15-17) mature eggs that were large (1.6-2.2 mm) for the small size of the fish (38.6-41.4 mm SL.). C1 Illinois Nat Hist Survey, Champaign, IL 61820 USA. RP Armbruster, JW (reprint author), Smithsonian Inst, Div Fishes, Natl Museum Nat Hist, Washington, DC 20560 USA. EM armbruster.jonathan@nmnh.si.edu NR 39 TC 34 Z9 41 U1 0 U2 2 PU AMER SOC ICHTHYOLOGISTS & HERPETOLOGISTS PI MIAMI PA MAUREEN DONNELLY, SECRETARY FLORIDA INT UNIV BIOLOGICAL SCIENCES, 11200 SW 8TH STREET, MIAMI, FL 33199 USA SN 0045-8511 EI 1938-5110 J9 COPEIA JI Copeia PD AUG 3 PY 1998 IS 3 BP 663 EP 675 DI 10.2307/1447796 PG 13 WC Zoology SC Zoology GA 109WU UT WOS:000075348000012 ER PT J AU Brodie, JP Schroder, LL Huchra, JP Phillips, AC Kissler-Patig, M Forbes, DA AF Brodie, JP Schroder, LL Huchra, JP Phillips, AC Kissler-Patig, M Forbes, DA TI Keck spectroscopy of candidate proto-globular clusters in NGC 1275 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : elliptical and lenticular, cD; galaxies : individual (NGC 1275); galaxies : nuclei ID OLD STELLAR POPULATIONS; MERGER REMNANT NGC-7252; YOUNG STAR-CLUSTERS; PERSEUS CLUSTER; TELESCOPE OBSERVATIONS; GALAXIES; NGC-1275; DISCOVERY; CORE; SPECTROMETER AB Keck spectroscopy of five proto-globular cluster candidates in NGC 1275 has been combined with Hubble Space Telescope Wide Field Planetary Camera 2 photometry to explore the nature and origin of these objects and discriminate between merger and cooling-flow scenarios for globular cluster formation. The objects we have studied are not H II regions, but rather star clusters, yet their integrated spectral properties do not resemble young or intermediate-age Magellanic Cloud clusters or Milky Way open clusters. The clusters' Balmer absorption appears to be too strong to be consistent with any of the standard Bruzual & Chariot evolutionary models at any metallicity. If the Bruzual & Chariot models are adopted, an initial mass function (IMF) that is skewed to high masses provides a better fit to the data of the proto-globular cluster candidates. A truncated IMF with a mass range of 2-3 M-. reproduces the observed Balmer equivalent widths and colors at similar to 450 Myr. Formation in a continuous cooling flow appears to be ruled out since the age of the clusters is much larger than the cooling time, the spatial scale of the clusters is much smaller than the cooling-flow radius, and the deduced star formation rate in the cooling flow favors a steep rather than a flat IMF. A merger would have to produce clusters only in the central few kiloparsecs, presumably from gas in the merging galaxies that was channeled rapidly to the center. Widespread shocks in merging galaxies cannot have produced these clusters. If these objects are confirmed to have a relatively flat, or truncated, IMF, it is unclear whether they will evolve into objects that we would regard as bona fide globular clusters. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 01238 USA. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. RP Brodie, JP (reprint author), Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. EM brodie@ucolick.org; linda@ucolick.org; huchra@cfa.harvard.edu; phillips@ucolick.org; mkissler@ucolick.org; forbes@star.sr.bham.ac.uk NR 67 TC 54 Z9 54 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 1998 VL 116 IS 2 BP 691 EP 706 DI 10.1086/300442 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 115CW UT WOS:000075646800009 ER PT J AU Lopez, R Rosado, M Riera, A Noriega-Crespo, A Raga, AC Estalella, R Anglada, G Le Coarer, E Langarica, R Tinoco, S Canto, J AF Lopez, R Rosado, M Riera, A Noriega-Crespo, A Raga, AC Estalella, R Anglada, G Le Coarer, E Langarica, R Tinoco, S Canto, J TI HH 262: The red lobe of the L1551 IRS 5 outflow SO ASTRONOMICAL JOURNAL LA English DT Article DE ISM : individual (HH 262, L1551 IRS 5); ISM : jets and outflows ID HERBIG-HARO OBJECTS; PROPER MOTIONS; HL TAURI; REGION; FLOW; CLOUD; JET; CO AB HH 262 is a group of emitting knots located approximately 3.'5 to the northeast of the L1551 IRS 5 source. We present a detailed study of the kinematic properties of HH 262, based on proper-motion measurements and on high-resolution imaging Fabry-Perot observations in the [S II] 6717 Angstrom line. From these observations, we conclude that it indeed appears to be the case that HH 262 is associated with the red lobe of the L1551 IRS 5 outflow. C1 Univ Barcelona, Dept Astron & Meteorol, E-08028 Barcelona, Spain. Univ Nacl Autonoma Mexico, Inst Astron, Mexico City 04510, DF, Mexico. Univ Politecn Catalunya, Dept Fis & Engn Nucl, Vilanova I La Geltru, Spain. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Observ Grenoble, F-38041 Grenoble 9, France. RP Lopez, R (reprint author), Univ Barcelona, Dept Astron & Meteorol, Ave Diagonal 647, E-08028 Barcelona, Spain. NR 27 TC 11 Z9 11 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 1998 VL 116 IS 2 BP 845 EP 853 DI 10.1086/300455 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 115CW UT WOS:000075646800023 ER PT J AU Smith, GH Dupree, AK AF Smith, GH Dupree, AK TI Hubble Space Telescope observations of chromospheric emission from the Population II red giant HD 216143 SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : chromospheres; stars : individual (HD 216143); stars : mass loss; stars : Population II ID NORTHERN-HEMISPHERE OBSERVATIONS; METAL-POOR STARS; MASS-LOSS; ALPHA EMISSION; SPECTROSCOPY; LINE; NGC-6752 AB Spectra of the H alpha and Ca II K Line of Population II red giants exhibit evidence for chromospheric mass outflows only among stars brighter than M-V = -1.7. In order to determine whether this phenomenon is indicative of a true physical onset in mass outflow, spectra of the 2800 Angstrom Mg II lines of the metal-poor halo red giant HD 216143 have been obtained with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. This star has shown no H alpha emission when observed on two separate occasions and has an absolute magnitude of M-V = - 1.5, placing it below the intrinsic brightness level at which H alpha emission is seen among other Population II giants. In addition, a high-resolution Ca II K line spectrum shows no significant K-3 velocity shift. Thus the H alpha and Ca II K lines show no evidence of chromospheric outflow. Nonetheless, HD 216143 exhibits clear Mg II h and k emission profiles. These profiles are asymmetric in the sense expected for mass outflow from the chromosphere. The combined surface flux of these two emission lines is similar to fluxes of other Population II red giants for which the Mg II lines have been observed. The central k(3) absorption feature is blueshifted with respect to the midpoint of the k emission profile by similar to 20 km s(-1). The h(3) feature shows a smaller blueshift, evidence possibly for an accelerated outflow in the outer atmosphere of HD 216143. It appears that outflows set in among halo red giants at brightnesses comparable to or fainter than M-V = -1.5. Halo giants fainter than this tend to show no H alpha emission and no significant velocity shifts in the K-3 central absorption component of the Ca II K line. It seems that the search for the onset of mass outflows from such stars is best conducted using the Mg II line. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Smith, GH (reprint author), Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. NR 30 TC 7 Z9 7 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 1998 VL 116 IS 2 BP 931 EP 935 DI 10.1086/300468 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 115CW UT WOS:000075646800032 ER PT J AU Guirado, JC Marcaide, JM Ros, E Ratner, MI Shapiro, II Quirrenbach, A Witzel, A AF Guirado, JC Marcaide, JM Ros, E Ratner, MI Shapiro, II Quirrenbach, A Witzel, A TI Submilliarcsecond shift of the brightness peak of the radio sources 1928+738 and 2007+777 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE astrometry; techniques : interferometric; quasars : individual : 1928+738; quasars : individual : 2007+777 ID VLBI DIFFERENTIAL ASTROMETRY; PROPER MOTION; 1038+528-A AB From two sets of very-long-baseline interferometry (VLBI) observations, one each at 5 GHz (1985.77) and at 2.3 and 8.4 GHz simultaneously (1988.83), of the quasar 1928+738 phase-referenced to the BLLac object 2007+777, we infer a change in their relative position of 0.74+/-0.22 milliarcseconds (mas) along a position angle of -9 degrees +/-25 degrees, where the quoted standard errors account for errors in our models of the geometry of the interferometric array, the atmosphere, and the source structure. This change is interpreted as an (inadvertent) shift of the reference point selected in the structure of 1928+738, due to the presence of an emerging component; different opacity effects in the three observing frequency bands may also be a significant contributor. C1 Univ Valencia, Dept Astron, E-46100 Valencia, Spain. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Max Planck Inst Radioastron, D-53010 Bonn, Germany. RP Guirado, JC (reprint author), Univ Valencia, Dept Astron, E-46100 Valencia, Spain. NR 18 TC 8 Z9 8 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 1 PY 1998 VL 336 IS 1 BP 385 EP 392 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 110RP UT WOS:000075394400044 ER PT J AU Vikhlinin, A McNamara, BR Forman, W Jones, C Quintana, H Hornstrup, A AF Vikhlinin, A McNamara, BR Forman, W Jones, C Quintana, H Hornstrup, A TI A catalog of 203 galaxy clusters serendipitously detected in the ROSAT PSPC pointed observations SO ASTROPHYSICAL JOURNAL LA English DT Article DE catalogs; galaxies : clusters : general; surveys; X-rays : galaxies ID MEDIUM-SENSITIVITY SURVEY; X-RAY DATA; COOLING FLOWS; EVOLUTION; UNIVERSE; COUNTS; SAMPLE AB We present a catalog of 203 clusters of galaxies serendipitously detected in 647 ROSAT PSPC high Galactic latitude pointings covering 158 deg(2). This is one of the largest X-ray-selected cluster samples, comparable in size only to the ROSAT All-Sky Survey sample of nearby clusters (Ebeling et al. 1997). We detect clusters in the inner 17.'5 of the ROSAT PSPC field of view using the spatial extent of their X-ray emission. Fluxes of detected clusters range from 1.6 x 10(-14) to 8 x 10(-12) ergs s(-1) cm(-2) in the 0.5-2 keV energy band. X-ray luminosities range from 10(42) ergs s(-1), corresponding to very poor groups, to similar to 5 x 10(44) ergs s(-1), corresponding to rich clusters. The cluster redshifts range from z = 0.015 to z > 0.5. The catalog lists X-ray fluxes, core radii, and spectroscopic redshifts for 73 clusters and photometric redshifts for the remainder. Our detection method, optimized for finding extended sources in the presence of source confusion, is described in detail. Selection effects necessary for a statistical analysis of the cluster sample are comprehensively studied by Monte Carlo simulations. We have optically confirmed 203 of 223 X-ray sources as clusters of galaxies. Of the remaining 20 sources, 19 are likely false detections arising from blends of unresolved point X-ray sources. Optical identifications of the remaining object are hampered by a bright nearby star. Above a flux of 2 x 10(-13) ergs s(-1) cm(-2), 98% of extended X-ray sources are optically confirmed clusters. The number of false detections and their flux distribution are in perfect agreement with simulations. The log N-log S relation for clusters derived from our catalog shows excellent agreement with counts of bright clusters derived from the Einstein Extended Medium Sensitivity Survey and ROSAT All-Sky Survey. At fainter fluxes, our log N-log S relation agrees with the smaller area WARPS survey. Our cluster counts appear to be systematically higher than those from a 50 deg(2) survey by Rosati et al. In particular, at a flux of 2 x 10(-13) ergs s(-1) cm(-2), we find a surface density of clusters of 0.57 +/- 0.07 deg(-2), which is a factor of 1.3 more than was found-by Rosati et al. This difference is marginally significant at the similar to 2 sigma level. The large area of our survey makes it possible to study the evolution of the X-ray luminosity function in the high luminosity range inaccessible with other, smaller area ROSAT surveys. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrophys, Santiago 22, Chile. Danish Space Res Inst, Copenhagen 2100 O, Denmark. Russian Acad Sci, Inst Space Res, Moscow V71, Russia. RP Vikhlinin, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM avikhlinin@cfa.harvard.edu; bmcnamara@cfa.harvard.edu; wforman@cfa.harvard.edu; cjones@cfa.harvard.edu NR 58 TC 271 Z9 272 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1998 VL 502 IS 2 BP 558 EP 581 DI 10.1086/305951 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KF UT WOS:000077776000006 ER PT J AU Spaans, M Carollo, CM AF Spaans, M Carollo, CM TI Effective star formation rates for cosmological applications SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : ISM; methods : numerical; stars : formation ID PHOTON-DOMINATED REGIONS; INTERMEDIATE-MASS STARS; HIGH-REDSHIFT; ELLIPTICAL GALAXIES; INTERSTELLAR CLOUDS; EVOLUTION; MODELS; DISKS; FIELD; PHASE AB Effective star formation rates in tabular form are computed that yield a prescription for the star formation activity in model galaxies as a function of ambient density, metallicity, and stellar feedback. The effects of supernova explosions on the thermal balance of the interstellar medium (ISM) and the presence of a multiphase ISM are explicitly included. The resulting grid of models can be implemented easily in N-body codes for the computation of star formation processes in merging galaxies and cosmological simulations. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Spaans, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 47 TC 5 Z9 5 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1998 VL 502 IS 2 BP 640 EP 651 DI 10.1086/305944 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KF UT WOS:000077776000011 ER PT J AU Wiseman, JJ Ho, PTP AF Wiseman, JJ Ho, PTP TI Large-scale structure, kinematics, and heating of the Orion ridge. I. VLA NH3 (1,1) and (2,2) mosaics SO ASTROPHYSICAL JOURNAL LA English DT Review DE ISM : clouds; ISM : individual (OMC-1); ISM : jets and outflows; ISM : kinematics and dynamics; ISM : structure; techniques : interferometric ID APERTURE SYNTHESIS OBSERVATIONS; ELONGATED CYLINDRICAL CLOUDS; FILAMENTARY MOLECULAR CLOUDS; HERBIG-HARO OBJECTS; STAR-FORMATION; MAGNETIC-FIELDS; INTERSTELLAR AMMONIA; HYDROGEN EMISSION; QUIESCENT GAS; KL AB We present high-resolution VLA mosaics of 18 adjacent fields in OMC-1 covering an 8' x 4' (1.2 x 0.6 pc) region surrounding the Orion-KL core. The NH3 (J, K) = (1, 1) and (2, 2) inversion transitions were observed; the resulting maps were produced with both high spectral (0.3 km s(-1)) and high angular (8 ") resolution. Both linear and nonlinear (maximum entropy method) techniques were employed to create the mosaics; we compare the challenges and results of each method. The complex effects of chemical excitation are discussed. We find extended clumpy filaments throughout the 0.5 pc region extending to the north and west from Orion-KL. The structure of filaments composed of chains of condensations appears to be hierarchical in OMC-1, as it is found on several scales. The filaments are separated into at least two major velocity components that appear to overlap in the central Orion-KL core region, suggesting interaction between cloud components as a possible triggering mechanism for the active high-mass star formation occurring there. The overlapping nature of the velocity components complicates simple global rotation models for OMC-1. The filaments appear to be fragmented into beadlike chains of dense clumps, which may show a continuing pattern of structural instabilities and star formation in the region. Some of these fragments may be sites, or future sites, of young stars. Some have very large velocity gradients and may be collapsing cores that have not yet shed their angular momentum. We also present a high-resolution NH3 (2, 2) to (1, 1) ratio map of the region, representing the temperature. Striking patterns of heating are apparent: around the central Orion-KL core, strong heating is found in a patchy ring surrounding the Orion bipolar outflow source, possibly delineating the paths by which the outflowing gas exits the central dense region and heats the gas along the way. Heating is evident along the edges of the filaments and clumps that face the path of the outflow, showing direct impact of outflows and radiation on the molecular environment. Other clumps along the filaments show slight temperature enhancements along their outer sheaths, which may be the result of radiation from external stars penetrating the clumpy medium and heating the core sheaths. The complex combination presented here of filaments, fragmentation, kinematical interaction, and heating along the OMC-1 ridge provides evidence for extensive and long-range interaction between a core of high-mass star formation and its surrounding cloud environment. C1 Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Wiseman, JJ (reprint author), Natl Radio Astron Observ, 520 Edgemont Rd, Charlottesville, VA 22903 USA. NR 121 TC 54 Z9 54 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1998 VL 502 IS 2 BP 676 EP 694 DI 10.1086/305930 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KF UT WOS:000077776000014 ER PT J AU Brickhouse, NS Dupree, AK AF Brickhouse, NS Dupree, AK TI Extreme Ultraviolet Explorer observations of the W ursae majoris contact binary 44i Bootis: Coronal structure and variability SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; binaries : eclipsing; stars : coronae; stars : individual (44i Bootis); stars : late-type; ultraviolet : stars ID LOCAL INTERSTELLAR-MEDIUM; COOL STARS; IUE OBSERVATIONS; LYMAN-ALPHA; LINE; EMISSION; HYDROGEN; SOLAR; ABUNDANCES; ROTATION AB EUVE observations of 44i Boo (HD 133640), the first W UMa-type active binary observed with EUVE, give evidence for localized coronal structure. An EUV light curve has been obtained with the EUVE Deep Survey (DS) detector and Lexan/boron filter during the 6 day observation (19.5 continuous epochs) in 1994. A period search on the DS data stream reveals a period corresponding to 0.272652 +/- 0.00141 days, longer than the optical period (0.267817 days) by 428 s. Since the DS flux originates predominantly from high-temperature plasma (T(e) similar to 10(7) K), this observation demonstrates for the first time an orbital phase-dependent component of the hot coronal emission of a contact binary, indicates the presence of an active region on the primary star, and signals a different rotation rate of the corona with respect to the photosphere. The high-temperature plasma shows no correspondence with the two partial eclipses per orbit found in the optical and in the chromospheric and transition-region emission. A flaring enhancement appears associated with maximum brightness. The EUV spectrum shows strong emission from highly ionized Fe. Like the emission measure distributions of Capella and other RS CVn binaries observed with EUVE, the spectrum of 44i Boo requires a continuous distribution of plasma temperatures to account for the relative Fe emission line fluxes. A local enhancement of emission measure at about T(e) similar to 8 x 10(6) K is reminiscent of the narrow feature found in Capella at T(e) similar to 6 x 10(6) K, although substantially broader. Line ratio diagnostics indicate extremely high densities, N(e) similar to 2 x 10(13) cm(-3)-higher than has been observed for other EUVE coronal sources. We place a hard lower limit on the Fe/H abundance ratio of Fe/H > 0.46 with respect to the solar photospheric value. We compare our results with those derived from the ROSAT PSPC and conclude that the soft X-ray band in ROSAT observations does not give reliable abundances or low-temperature emission measures. The high electron density and peak emission measure together imply a small emitting volume, L(3) (L similar to 0.004R(star)). If all the EUV emission arises from such a volume, the EUV light curve places tight constraints on the possible location of a "hot spot," namely that it must be located at high latitudes (> 72 degrees) on the primary star. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Brickhouse, NS (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Brickhouse, Nancy/0000-0002-8704-4473 NR 54 TC 54 Z9 54 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 AUG 1 PY 1998 VL 502 IS 2 BP 918 EP 931 DI 10.1086/305916 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152KF UT WOS:000077776000032 ER PT J AU Brown, TM Kotak, R Horner, SD Kennelly, EJ Korzennik, S Nisenson, P Noyes, RW AF Brown, TM Kotak, R Horner, SD Kennelly, EJ Korzennik, S Nisenson, P Noyes, RW TI Exoplanets or dynamic atmospheres? The radial velocity and line shape variations of 51 Pegasi and tau Bootis SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE line, profiles; planetary systems; stars, individual (51 Pegasi, tau Bootis); stars, oscillations ID NONRADIAL PULSATIONS; PLANETARY COMPANION; PROFILE VARIATIONS; STARS; 51-PEGASI; MODES AB The stars 51 Pegasi and tau Bootis show radial velocity variations that have been interpreted as resulting from companions with roughly Jovian mass and orbital periods of a few days. Gray and Gray & Hatzes reported that the radial velocity signal of 51 Peg is synchronous with variations in the shape of the line lambda 6253 Fe I; thus, they argue that the velocity signal arises not from a companion of planetary mass but from dynamic processes in the atmosphere of the star, possibly nonradial pulsations. Here we seek confirming evidence for line shape or strength variations in both 51 Peg and tau Boo, using R = 50,000 observations taken with the Advanced Fiber Optic Echelle. Because of our relatively low spectral resolution, we compare our observations with Gray's line bisector data by fitting observed line profiles to an expansion in terms of orthogonal (Hermite) functions. To obtain an accurate comparison, we model the emergent line profiles from rotating and pulsating stars, taking the instrumental point-spread function into account. We describe this modeling process in detail. We find no evidence for line profile or strength variations at the radial velocity period in either 51 Peg or in tau Boo. For 51 Peg, our upper limit for line shape variations with 4.23 day periodicity is small enough to exclude with 10 sigma confidence the bisector curvature signal reported by Gray & Hatzes; the bisector span and relative line depth signals reported by Gray are also not seen, but in this case with marginal (2 sigma) confidence. We cannot, however, exclude pulsations as the source of 51 Peg's radial velocity variation because our models imply that line shape variations associated with pulsations should be much smaller than those computed by Gray & Hatzes; these smaller signals are below the detection limits both for Gray & Hatzes's data and for our own. tau Boo's large radial velocity amplitude and upsilon sin i make it easier to test for pulsations in this star. Again we find no evidence for periodic line shape changes, at a level that rules out pulsations as the source of the radial velocity variability. We conclude that the planet hypothesis remains the most likely explanation for the existing data. C1 Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Brown, TM (reprint author), Natl Ctr Atmospher Res, High Altitude Observ, POB 3000, Boulder, CO 80307 USA. OI Kotak, Rubina/0000-0001-5455-3653 NR 29 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD AUG PY 1998 VL 117 IS 2 BP 563 EP 585 DI 10.1086/313123 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 111QM UT WOS:000075449200007 ER PT J AU Wilcove, DS Rothstein, D Dubow, J Phillips, A Losos, E AF Wilcove, DS Rothstein, D Dubow, J Phillips, A Losos, E TI Quantifying threats to imperiled species in the United States SO BIOSCIENCE LA English DT Article ID CONSERVATION C1 Environm Def Fund, Washington, DC 20009 USA. Eastern Res Grp, Arlington, VA 22201 USA. Nat Conservancy, Arlington, VA 22209 USA. Wilderness Soc, Denver, CO 80221 USA. Smithsonian Trop Res Inst, Ctr Trop Forest Sci, Washington, DC USA. RP Wilcove, DS (reprint author), Environm Def Fund, Washington, DC 20009 USA. NR 26 TC 1516 Z9 1647 U1 48 U2 394 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 AUG PY 1998 VL 48 IS 8 BP 607 EP 615 DI 10.2307/1313420 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 103GR UT WOS:000075150200007 ER PT J AU Carpenter, SR Caraco, NF Correll, DL Howarth, RW Sharpley, AN Smith, VH AF Carpenter, SR Caraco, NF Correll, DL Howarth, RW Sharpley, AN Smith, VH TI Nonpoint pollution of surface waters with phosphorus and nitrogen SO ECOLOGICAL APPLICATIONS LA English DT Article DE agriculture; estuary; eutrophication; lake; nitrogen; nonpoint pollution; phosphorus; river; runoff; stream ID NORTH-ATLANTIC OCEAN; LAKES; WETLANDS; QUALITY; TOXINS AB Agriculture and urban activities are major sources of phosphorus and nitrogen to aquatic ecosystems. Atmospheric deposition further contributes as a source of N. These nonpoint inputs of nutrients are difficult to measure and regulate because they derive from activities dispersed over wide areas of land and are variable in time due to effects of weather. In aquatic ecosystems, these nutrients cause diverse problems such as toxic algal blooms, loss of oxygen, fish kills, loss of biodiversity (including species important for commerce and recreation), loss of aquatic plant beds and coral reefs, and other problems. Nutrient enrichment seriously degrades aquatic ecosystems and impairs the use of water for drinking, industry, agriculture, recreation, and other purposes. Based on our review of the scientific literature, we are certain that (1) eutrophication is a widespread problem in rivers, lakes, estuaries, and coastal oceans, caused by over-enrichment with P and N; (2) nonpoint pollution, a major source of P and N to surface waters of the United States, results primarily from agriculture and urban activity, including industry; (3) inputs of P and N to agriculture in the form of fertilizers exceed outputs in produce in the United States and many other nations; (4) nutrient flows to aquatic ecosystems are directly related to animal stocking densities, and under high livestock densities, manure production exceeds the needs of crops to which the manure is applied; (5) excess fertilization and manure production cause a P surplus to accumulate in soil, some of which is transported to aquatic ecosystems; and (6) excess fertilization and manure production on agricultural lands create surplus N, which is mobile in many soils and often leaches to downstream aquatic ecosystems, and which can also volatilize to the atmosphere, redepositing elsewhere and eventually reaching aquatic ecosystems. If current practices continue, nonpoint pollution of surface waters is virtually certain to increase in the future. Such an outcome is not inevitable, however, because a number of technologies, land use practices, and conservation measures are capable of decreasing the flow of nonpoint P and N into surface waters. From our review of the available scientific information, we are confident that: (1) nonpoint pollution of surface waters with P and N could be reduced by reducing surplus nutrient flows in agricultural systems and processes, reducing agricultural and urban runoff by diverse methods, and reducing N emissions from fossil fuel burning; and (2) eutrophication can be reversed by decreasing input rates of P and N to aquatic ecosystems, but rates of recovery are highly variable among water bodies. Often, the eutrophic state is persistent, and recovery is slow. C1 Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. Inst Ecosyst Studies, Millbrook, NY 12545 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. Cornell Univ, Ecol & Systemat Sect, Ithaca, NY 14853 USA. ARS, USDA, Pasture Syst & Watershed Management Res Lab, University Pk, PA 16802 USA. Univ Kansas, Dept Systemat & Ecol, Lawrence, KS 66045 USA. RP Carpenter, SR (reprint author), Univ Wisconsin, Ctr Limnol, 680 N Pk St, Madison, WI 53706 USA. RI Rodrigues, Flavio/A-8724-2014 OI Rodrigues, Flavio/0000-0001-8538-0089 NR 74 TC 2276 Z9 2441 U1 362 U2 2353 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 USA SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD AUG PY 1998 VL 8 IS 3 BP 559 EP 568 DI 10.2307/2641247 PG 10 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 107PZ UT WOS:000075219300001 ER PT J AU Lovelock, CE Kursar, TA Skillman, JB Winter, K AF Lovelock, CE Kursar, TA Skillman, JB Winter, K TI Photoinhibition in tropical forest understorey species with short- and long-lived leaves SO FUNCTIONAL ECOLOGY LA English DT Article DE acclimation in shade-tolerant species; chlorophyll fluorescence; leaf lifetimes; tolerance of high light levels ID INDUCED ABSORBENCY CHANGES; XANTHOPHYLL-CYCLE; PHOTOSYSTEM-II; CHLOROPHYLL FLUORESCENCE; ZEAXANTHIN FORMATION; ELECTRON-TRANSPORT; LIGHT STRESS; GROWTH-RATE; LIFE-SPAN; PLANT AB 1. Shade-tolerant species that inhabit the understorey have a range of leaf lifetimes (from 1 to 8 years), which may indicate a variety of strategies for dealing with increases in light associated with tree-fall gaps. We hypothesized that species with long-lived leaves should be more tolerant of an increase in light levels than species with short-lived leaves. 2, In understorey plants of 12 shade-tolerant rain-forest species, photoinhibition, measured as a reduction in the chlorophyll fluorescence parameter F-v/F-m when leaf discs were exposed to 1 h at 1000 mu mol m(-2)s(-1), was greater in species with short-lived leaves than species with long-lived leaves. 3, Less photoinhibition in species with long-lived leaves was not associated with higher levels of non-photochemical dissipation (NPQ) of absorbed light, but may be the result of a higher yield of photosystem II compared with short-lived leaves. 4, Thus, species with long-lived leaves are more tolerant of abrupt increases in light that occur when tree-fall gaps are formed than species with short-lived leaves. 5, Discs from leaves of all species growing in tree-fall gaps had higher levels of NPQ, yield of photosystem II and more rapid recovery from photoinhibition than leaves developed in the understorey; however, there were no differences among species with short- and long-lived leaves. C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Utah, Dept Biol, Salt Lake City, UT 84112 USA. Penn State Univ, Dept Plant Pathol, Buckhout Lab 209, University Pk, PA 16802 USA. RP Lovelock, CE (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. RI Lovelock, Catherine/G-7370-2012 OI Lovelock, Catherine/0000-0002-2219-6855 NR 36 TC 30 Z9 31 U1 0 U2 5 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 AUG PY 1998 VL 12 IS 4 BP 553 EP 560 DI 10.1046/j.1365-2435.1998.00235.x PG 8 WC Ecology SC Environmental Sciences & Ecology GA 126DD UT WOS:000076276900007 ER PT J AU Shepard, MK Campbell, BA AF Shepard, MK Campbell, BA TI Shadows on a planetary surface and implications for photometric roughness SO ICARUS LA English DT Article DE photometry; surfaces; planets; computer techniques ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; RADAR SCATTERING; TOPOGRAPHY AB We advocate the use of fractal surface statistics as a simple, quantitative, and general model for planetary surface roughness. We determine the shadowing behavior of a wide range of fractal surfaces using computer simulations, and present an empirical function that reproduces their observed behavior within statistical uncertainties. We compare the shadowing behavior of fractal surfaces to four analytic shadowing models for random surfaces and find that three of these, including the Hapke (1984, Icarus 59, 41-59) model, are well approximated by specific cases of a general fractal surface model. In addition, we demonstrate that a fractal surface model provides a way of quantitatively verifying and extending previous interpretations of the Hapke (1984) roughness parameter. We hypothesize that the scale which dominates surface shadowing, and by extension photometric roughness, is the smallest surface scale for which shadows exist and that this scale is a function of intrinsic physical parameters such as the single scattering albedo and particle phase function. If correct, a major implication of this hypothesis is that photometric roughness may have different physical meanings on different surfaces. (C) 1998 academic Press. C1 Bloomsburg Univ Penn, Dept Geog & Earth Sci, Bloomsburg, PA 17815 USA. Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, MRC 315, Washington, DC 20560 USA. RP Shepard, MK (reprint author), Bloomsburg Univ Penn, Dept Geog & Earth Sci, 400 E 2nd St, Bloomsburg, PA 17815 USA. NR 31 TC 50 Z9 51 U1 1 U2 4 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 AUG PY 1998 VL 134 IS 2 BP 279 EP 291 DI 10.1006/icar.1998.5958 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 117AP UT WOS:000075757800009 ER PT J AU Piperno, DR Holst, I AF Piperno, DR Holst, I TI The presence of starch grains on prehistoric stone tools from the humid neotropics: Indications of early tuber use and agriculture in Panama SO JOURNAL OF ARCHAEOLOGICAL SCIENCE LA English DT Article DE starch grains; tubers; plant grinding stones ID PERU; REMAINS C1 Smithsonian Tropical Res Inst, Balboa, Panama. RP Piperno, DR (reprint author), Smithsonian Tropical Res Inst, Box 2072, Balboa, Panama. NR 49 TC 112 Z9 128 U1 2 U2 7 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0305-4403 J9 J ARCHAEOL SCI JI J. Archaeol. Sci. PD AUG PY 1998 VL 25 IS 8 BP 765 EP 776 DI 10.1006/jasc.1997.0258 PG 12 WC Anthropology; Archaeology; Geosciences, Multidisciplinary SC Anthropology; Archaeology; Geology GA 110YP UT WOS:000075409400004 ER PT J AU Odo, FS AF Odo, FS TI Beyond loyalty: The story of a Kibei. SO JOURNAL OF ASIAN STUDIES LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Odo, FS (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ASSN ASIAN STUDIES INC PI ANN ARBOR PA UNIV MICH 1 LANE HALL, ANN ARBOR, MI 48109 USA SN 0021-9118 J9 J ASIAN STUD JI J. Asian Stud. PD AUG PY 1998 VL 57 IS 3 BP 885 EP 886 DI 10.2307/2658798 PG 2 WC Area Studies; Asian Studies SC Area Studies; Asian Studies GA 128PD UT WOS:000076414400070 ER PT J AU Yoshino, K Esmond, JR Parkinson, WH Thorne, AP Murray, JE Learner, RCM Cox, G Cheung, ASC Leung, KWS Ito, K Matsui, T Imajo, T AF Yoshino, K Esmond, JR Parkinson, WH Thorne, AP Murray, JE Learner, RCM Cox, G Cheung, ASC Leung, KWS Ito, K Matsui, T Imajo, T TI The application of a VUV Fourier transform spectrometer and synchrotron radiation source to measurements of: I. The beta(9,0) band of NO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SCHUMANN-RUNGE BANDS; CROSS-SECTION MEASUREMENTS; HIGH-RESOLUTION; OSCILLATOR-STRENGTHS; NITRIC-OXIDE; VACUUM-ULTRAVIOLET; SPECTROSCOPY; O-2; PHOTOABSORPTION; DISSOCIATION AB State-of-the-art models of the vacuum ultraviolet (VUV) absorbing properties of the atmosphere call for absorption cross sections with detail on the scale of the Doppler widths. As a consequence, spectroscopic data at resolving powers of the order of 10(6) are needed. To meet these requirements in the vacuum ultraviolet region, we have used the VUV Fourier transform spectrometer from Imperial College, London, at the synchrotron radiation facility at Photon Factory, KEK, Japan, to measure photoabsorption cross sections of NO from 195 to 160 nm; and of O-2 from 185 to 175 rrm. The analysis of the beta(9,0) band (B (2)Pi(r),- X-(2)Pi(r),) Of NO provides accurate rotational line positions and term values. Molecular constants of the-B(9) (2)Pi level-are T-0=54 205.097+/-.0.012-cm(-1), A =45.320+/- 0.021 cm(-1), B-v= 1.016 72+/- 0.000 16 cm(-1), D-v(10.61+/- 0.32) X 10(-6) cm(-1), and AD = 0.001 22 +/- 0.000 11 cm(-1). The rotational line strengths and the branching ratios are also presented. The band oscillator strength is obtained as f = 2.65 x 10(-4) . (C) 1998 American Institute of Physics. [S0021-9606(98)01529-3] : C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Univ Hong Kong, Hong Kong, Peoples R China. KEK, Photon Factory, Tsukuba, Ibaraki 305, Japan. Kyushu Univ, Fukuoka 812, Japan. RP Yoshino, K (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Cheung, Allan/D-3059-2009 NR 35 TC 23 Z9 22 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 1 PY 1998 VL 109 IS 5 BP 1751 EP 1757 DI 10.1063/1.476750 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 105HH UT WOS:000075066300022 ER PT J AU Ferrari, FD AF Ferrari, FD TI Setal developmental patterns of thoracopods of the Cyclopidae (Copepoda : Cyclopoida) and their use in phylogenetic inference SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Article ID SEGMENTS; BELIZE; LEGS AB Thoracopod development was analyzed for 25 species from 18 genera among the Cyclopidae. One species from each of 7 genera of presumed older cyclopoids, 5 poecilostomatoid genera, 3 harpacticoid genera, 5 calanoid genera, and a siphonostomatoid were studied to help establish ancestral patterns of thoracopod development. Ancestral character states were inferred from the presence of identical states in species from presumed older families, from the presence of states which show di verse and frequent occurrence among the Copepoda, or from the presence of states shared by serially homologous structures presumed to be determined by the same pleiotropic regulatory process. Developmental patterns of the 4 swimming legs were assumed to result from the action of 2 different regulatory processes. A pleiotropic process acting early in development determines the morphology of all 8 rami together and results in 3 states among cyclopids, ancestral, and the independently derived delayed and truncated patterns. A second set of up to 8 regulatory processes acts later and one of the 8 determines the morphology of each individual ramus. The ancestral states of the resulting individual rami are, by default, the morphology that results from the pleiotropic regulatory process. Variations in developmental patterns were used to generate a phylogenetic hypothesis. Cyclopids have separated into a lineage of 10 species which has delayed the development of the swimming legs or has modified some individual rami from the delayed condition, and a lineage of 8 species which has truncated the development of the swimming legs or has modified some individual rami from that truncated condition. Four species have retained the ancestral process regulating swimming-leg development and 3 species have modified development of some individual rami from the ancestral condition. C1 Natl Museum Nat Hist, Smithsonian Inst, Washington, DC 20560 USA. RP Ferrari, FD (reprint author), Natl Museum Nat Hist, Smithsonian Inst, MRC 534, Washington, DC 20560 USA. NR 29 TC 16 Z9 17 U1 0 U2 0 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD AUG PY 1998 VL 18 IS 3 BP 471 EP 489 DI 10.2307/1549412 PG 19 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 109VH UT WOS:000075344200007 ER PT J AU Ortiz, M Rueda, RL Lemaitre, R AF Ortiz, M Rueda, RL Lemaitre, R TI Antonio Osvaldo Gomez Hernandez - 29 February 1928 25 December 1996 SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Biographical-Item C1 Univ La Habana, Ctr Invest Marinas, La Habana, Cuba. Natl Museum Nat Hist, Smithsonian Inst, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Ortiz, M (reprint author), Univ La Habana, Ctr Invest Marinas, La Habana, Cuba. NR 1 TC 0 Z9 0 U1 0 U2 0 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD AUG PY 1998 VL 18 IS 3 BP 616 EP 618 PG 3 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 109VH UT WOS:000075344200020 ER PT J AU Lemaitre, R AF Lemaitre, R TI Austin Beatty Williams - Recipient of Award for Excellence in Research SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Biographical-Item C1 Natl Museum Nat Hist, Smithsonian Inst, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Lemaitre, R (reprint author), Natl Museum Nat Hist, Smithsonian Inst, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD AUG PY 1998 VL 18 IS 3 BP 619 EP 620 PG 2 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 109VH UT WOS:000075344200021 ER PT J AU Davies, SJ Palmiotto, PA Ashton, PS Lee, HS Lafrankie, JV AF Davies, SJ Palmiotto, PA Ashton, PS Lee, HS Lafrankie, JV TI Comparative ecology of 11 sympatric species of Macaranga in Borneo: tree distribution in relation to horizontal and vertical resource heterogeneity SO JOURNAL OF ECOLOGY LA English DT Review DE microenvironment; rain forest; shade tolerance; species coexistence; tree allometry; tree spatial distribution ID TROPICAL RAIN-FORESTS; GAP-PHASE REGENERATION; DIPTEROCARP FOREST; SEEDLING ECOLOGY; PIONEER TREE; WET FOREST; ALLOMETRY; GROWTH; PHOTOSYNTHESIS; UNDERSTOREY AB 1 Horizontal and vertical heterogeneity of resource availability, coupled with the specialized use of resources by tree species, results in complex patterns of tree species distributions in tropical rain forests. We studied the horizontal and vertical distributions of 4014 individuals in 11 species of early successional Macaranga (Euphorbiaceae) in tropical rain forest in Sarawak, Malaysia. 2 The horizontal distribution of individual trees was assessed with respect to crown light levels, establishment microsites, and broader scale variation in soil textural properties. Vertical distribution was assessed using an allometric approach to estimate maximum tree height (H-max) and the slope of the sapling height-diameter relationship. 3 Average light levels intercepted and the proportion of individuals in each of five crown illumination classes varied significantly among the 11 species. Species ranged from extremely high-light demanding, to quite shade tolerant. Average light levels intercepted by trees generally increased through ontogeny, but the ranking of species did not change significantly. 4 Fewer individuals of the more shade-tolerant species established on disturbed microsites, irrespective of light levels. Among the more high-light demanding species, the proportion of trees on different types of disturbed sites varied. 5 Trees of seven species were significantly more common on clay-rich soils, two preferred sand-rich soils, and two were not strongly affected by soil texture. 6 H-max ranged from 5.5 to 31.3 m and was negatively correlated with shade tolerance among species, although among the more high-light demanding species there was a wide range of tree sizes. Among species, H-max was negatively correlated with both the slope and gamma-intercept of the sapling height-diameter relationship, indicating that small-statured species (also more shade tolerant) had more slender saplings than larger statured species. 7 Heterogeneity of resource availability leads to differences in horizontal and vertical tree distribution, which are important for the coexistence of 11 Macaranga species. C1 Harvard Univ Hebaria, Cambridge, MA 02138 USA. Yale Univ, Sch Forestry & Environm Studies, New Haven, CT 06511 USA. Sarawak Forest Dept, Res Sect, Kuching, Sarawak, Malaysia. Smithsonian Trop Res Inst, CTFS, Singapore, Singapore. RP Davies, SJ (reprint author), Univ Malaysia Sarawak, Inst Biodivers & Environm Conservat, Kota Samarahan 94300, Sarawak, Malaysia. EM sjdavies@ibec.unimas.my NR 75 TC 161 Z9 164 U1 6 U2 39 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0022-0477 J9 J ECOL JI J. Ecol. PD AUG PY 1998 VL 86 IS 4 BP 662 EP 673 DI 10.1046/j.1365-2745.1998.00299.x PG 12 WC Plant Sciences; Ecology SC Plant Sciences; Environmental Sciences & Ecology GA 115ZB UT WOS:000075695300011 ER PT J AU Dalling, JW Hubbell, SP Silvera, K AF Dalling, JW Hubbell, SP Silvera, K TI Seed dispersal, seedling establishment and gap partitioning among tropical pioneer trees SO JOURNAL OF ECOLOGY LA English DT Article DE dispersal limitation; establishment limitation; gap; gap light environment; seedling establishment ID NEOTROPICAL RAIN-FOREST; PHASE REGENERATION; SPECIES-RICHNESS; CANOPY OPENINGS; WET FOREST; DRY FOREST; FALL GAPS; GROWTH; BANK; GERMINATION AB 1 We examined the abundance and distribution patterns of pioneer seeds in the soil seed bank, and of pioneer seedlings in 53 recently formed gaps, in a 50-ha forest dynamics plot on Barro Colorado Island (BCI), Panama. The aim was to assess the importance of dispersal limitation (failure of seeds to arrive at all sites suitable for their germination) and establishment limitation (failure of seeds having reached a site to germinate successfully and establish as seedlings) in determining patterns of gap occupancy. 2 The abundance of seeds in the soil seed bank was strongly negatively correlated with seed size? but was not correlated with the abundance of reproductive-sized adult trees in the plot. In contrast, the abundance of pioneer seedlings > 10 cm height in natural gaps was strongly correlated with adult abundance, but was not correlated with seed size. 3 Seedlings were non-randomly distributed among gaps, but seedling abundance was not directly related to gap size, and there was no evidence of partitioning of the light environment of gaps by small seedlings. Large differences in growth and mortality rates among species were observed after 1 year, and this may result in the gap size partitioning previously found in saplings of the same species. 4 Seedlings of most species, particularly those with large seeds, were relatively more abundant than expected in gaps close to their conspecific adults. Proximity to reproductives, and by inference dispersal limitation, therefore exerts some effect on seedling distribution. None the less, large differences between seed and seedling abundances for some species, and low seedling occupancy rates in some gaps close to adult conspecifics, suggest that seedling emergence probabilities and species-specific establishment requirements may also be important determinants of local abundance. C1 Smithsonian Trop Res Inst, Balboa, Panama. Princeton Univ, Dept Ecol & Evolutionary Biol, Princeton, NJ 08544 USA. Univ Panama, Dept Bot, Panama City, Panama. RP Dalling, JW (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. EM dallingj@bci.si.edu NR 68 TC 160 Z9 178 U1 2 U2 45 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0022-0477 J9 J ECOL JI J. Ecol. PD AUG PY 1998 VL 86 IS 4 BP 674 EP 689 DI 10.1046/j.1365-2745.1998.00298.x PG 16 WC Plant Sciences; Ecology SC Plant Sciences; Environmental Sciences & Ecology GA 115ZB UT WOS:000075695300012 ER PT J AU West, SA Herre, EA AF West, SA Herre, EA TI Partial local mate competition and the sex ratio: A study on non-pollinating fig wasps SO JOURNAL OF EVOLUTIONARY BIOLOGY LA English DT Article DE fig wasps; parasitoid; sex ratio; Local Mate Competition; wing dimorphism ID HIERARCHICAL SELECTION THEORY; MATING STRUCTURE; NEW-WORLD; INDEPENDENT CONTRASTS; OFFSPRING ALLOCATION; NASONIA-VITRIPENNIS; PARASITIC WASP; HOST QUALITY; CLUTCH SIZE; POPULATION AB In many species, mating takes place in temporary patches where only a small number of females produce offspring. In this situation Local Mate Competition (LMC) theory predicts that the optimal sex ratio (defined as proportion males) should become increasingly female biased as the number of females contributing offspring to a patch decreases. However, in a large number of these species, some mating is also likely to occur away from the natal patch (termed partial LMC). In this case the degree of LMC is reduced, and theory predicts a relatively less female biased sex ratio. We tested these two predictions with field data from 17 species of New World non-pollinating fig wasps representing three genera. We present a model which suggests that the average number of females ovipositing in a fruit (i.e. patch) is positively correlated with the proportion of fruit of a given tree species in which that species of wasp occurs. Across species, the overall sex ratio was positively correlated with the proportion of fruit in which that species occurs. Furthermore, the males of some species are wingless, and in these species all mating must take place before females disperse from their natal fruit. In contrast, the males of other species are winged, and in these species mating may also take place away from the natal fruit. Species with winged males had less female biased sex ratios than species with wingless males that occurred in a similar proportion of fruit. Finally, the correlation between sex ratio and the proportion of fruit in which a species occurs was also observed within species when comparing between the fruit crops of different trees. This suggests that individual females facultatively adjust the sex ratio of their offspring in response to variable LMC. C1 Univ London Imperial Coll Sci Technol & Med, Dept Biol, Ascot SL5 7PY, Berks, England. Smithsonian Trop Res Inst, Balboa, Panama. RP West, SA (reprint author), Univ Edinburgh, Inst Cell Anim & Populat Biol, W Mains Rd, Edinburgh EH9 3JT, Midlothian, Scotland. RI West, Stuart/M-3608-2014 OI West, Stuart/0000-0003-2152-3153 NR 62 TC 52 Z9 59 U1 2 U2 14 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1010-061X J9 J EVOLUTION BIOL JI J. Evol. Biol. PD AUG PY 1998 VL 11 IS 5 BP 531 EP 548 DI 10.1007/s000360050104 PG 18 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 116CC UT WOS:000075704600001 ER PT J AU Boness, DJ Craig, MP Honigman, L Austin, S AF Boness, DJ Craig, MP Honigman, L Austin, S TI Fostering behavior and the effect of female density in Hawaiian monk seals, Monachus schauinslandi SO JOURNAL OF MAMMALOGY LA English DT Article DE Monachus schauinslandi; Hawaiian monk seals; fostering; non-offspring nursing; maternal care; density effects; pinnipeds ID NORTHERN ELEPHANT SEAL; BAT MATERNITY COLONIES; HARBOR SEAL; PHOCA-VITULINA; ALLOPARENTAL CARE; BUBALUS-BUBALIS; WATER-BUFFALO; GREY SEAL; ADOPTION; MOTHER AB Frequent nursing of pups by non-filial females (fostering) has been reported in Hawaiian monk seals (Monachus schauinslandi) at French Frigate Shoals in the Northwestern-Hawaiian Islands. We present data on the occurrence of fostering at Laysan Island, NWHI, and compare spatial patterns and behavior of seals at Laysan Island and East Island, French Frigate Shoals, to investigate the importance of density in frequency of fostering. Fostering was common at Laysan Island; 53% of 17 females nursed pups other than their own for some part of their lactation period. This level of fostering was significantly less than that at East Island, where ca. 90% of females fostered pups in 2 separate years (n = 30 in 1987 and 10 in 1989). Density of females was significantly lower at Laysan Island than East Island (0.5 versus 1.5 femaIes/1,000 m(2)), and nearest female neighbors were significantly farther away (58 versus 27 m) at Laysan Island. Stage of lactation at which fostering started, the total duration of foster care and the duration of fostering episodes did not differ between colonies. However, mean number of pups fostered per female at the denser colony (2.3 pups, East Island) was greater than at the less dense colony (1.3 pups, Laysan Island). No difference occurred between islands in relative frequency of aggressive interactions between females, which are known to result in females exchanging pups. High female density does appear to increase fostering frequency but not through female-female aggression as expected. Instead, high density increases the likelihood that separated females and pups will encounter another potential partner before reuniting. C1 Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. NOAA, Natl Marine Fisheries Serv, Honolulu, HI 96822 USA. RP Boness, DJ (reprint author), Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. NR 49 TC 27 Z9 28 U1 2 U2 12 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 1998 VL 79 IS 3 BP 1060 EP 1069 DI 10.2307/1383115 PG 10 WC Zoology SC Zoology GA 114TJ UT WOS:000075624900037 ER PT J AU Harasewych, MG AF Harasewych, MG TI Trauma-induced, in utero hyperstrophy in Melanoides tuberculata (Muller, 1794) SO JOURNAL OF MOLLUSCAN STUDIES LA English DT Article C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Harasewych, MG (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0260-1230 J9 J MOLLUS STUD JI J. Molluscan Stud. PD AUG PY 1998 VL 64 BP 404 EP 405 DI 10.1093/mollus/64.3.404 PN 3 PG 2 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 120KY UT WOS:000075956700014 ER PT J AU Hillis, LW Engman, JA Kooistra, WHCF AF Hillis, LW Engman, JA Kooistra, WHCF TI Morphological and molecular phylogenies of Halimeda (Chlorophyta, Bryopsidales) identify three evolutionary lineages SO JOURNAL OF PHYCOLOGY LA English DT Article DE Bryopsidales; coral reef algae; 18S rDNA; Flabellia; fossil record; Halimeda; insertion; morphology; phylogeny; taxonomy ID SUBUNIT RNA SEQUENCES; GREEN-ALGA-HALIMEDA; RIBOSOMAL-RNA; MAXIMUM-LIKELIHOOD; RELATIVE EFFICIENCIES; DNA-SEQUENCES; NUCLEAR; PHOTOSYNTHESIS; CALCIFICATION; PARSIMONY AB Halimeda Lamouroux 1812 colonizes most benthic euphotic habitats of tropical reefs worldwide; yet, despite its ecological importance and long fossil record, little is known about the evolutionary history of this complex of 33 described species. This report is the first within a developing; comprehensive study of the genus, of which the goals were to determine the major lineages within the genus, compare them with current taxonomic circumscriptions, and begin to evaluate the phylogenetic information that can be gleaned from morphology. We present the first formal phylogenetic analysis based on 23 morphological characters and the last 723 nucleotides of the 3' end of the rDNA 18S gene including an insertion of approximately 102 bp. Fourteen samples from 10 species representing four sections were included. Independent analysis of both data sets yielded congruent topologies, with the molecular data set offering more resolution. Thirteen of the 23 morphological characters were phylogenetically informative. Holdfast type, cortical branching pattern, and nodal configuration were the key synapomorphies. The 18S rDNA sequence including secondary structural analysis revealed 139 variable positions, of which 58 (42 %) were informative. Thirty-two of the informative positions (55 %) were found in the insertion. Three principal lineages were identified corresponding to sections Opuntia and Micronesicae, Rhipsalis, and Halimeda. In the molecular analyses, Flabellia petiolata (Turra) Nizamuddin was included as outgroup but did not resolve relationships among the lineages. Our results provide the basis for detailed phylogenetic and biogeographic studies within specific sections of the genus and for exploration of the evolutionary diversification of large complexes such as H. opuntia and H, discoidea. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Hillis, LW (reprint author), 20 Brooks Rd, Woods Hole, MA 02543 USA. OI Kooistra, Wiebe/0000-0002-8641-9739 NR 58 TC 22 Z9 26 U1 1 U2 4 PU PHYCOLOGICAL SOC AMER INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0022-3646 J9 J PHYCOL JI J. Phycol. PD AUG PY 1998 VL 34 IS 4 BP 669 EP 681 DI 10.1046/j.1529-8817.1998.340669.x PG 13 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA 116FB UT WOS:000075712400015 ER PT J AU Riley, SM AF Riley, SM TI The Lazarus child. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC 20560 USA. RP Riley, SM (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 AUG PY 1998 VL 123 IS 13 BP 132 EP 132 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 108XR UT WOS:000075291800333 ER PT J AU Thiel, M AF Thiel, M TI Reproductive biology of a deposit-feeding amphipod, Casco bigelowi with extended parental care SO MARINE BIOLOGY LA English DT Article ID LIFE-HISTORY; DYOPEDOS-MONACANTHUS; CAPRELLID AMPHIPOD; MATERNAL-CARE; CRUSTACEA; BEHAVIOR; MARINE; PREDATION; PATTERNS; DYNAMICS AB The reproductive traits of a deposit-feeding amphipod that engages in extended parental care were examined. At the study site in Lowes Cove, Maine, USA, Casco bigelowi (Blake, 1929) occurred in highest densities in soft sediments just below mean low water (MLW). During most months, the sex ratio was similar or equal to 1. Many females hosted males in their burrows throughout the summer, but after fertilization of females in September, all adult males disappeared from the study area. In October almost 80% of the females were ovigerous, and in November about the same percentage was parental, i.e. caring for juveniles in their burrows. The females produced only one brood each in late fall which they accommodated in their burrows for 2 mo or longer. The average number of juveniles per female was similar to 20 in November, and continuously decreased until January. Juveniles reached sizes >10 mm length in the maternal burrows. In early December the first juveniles were found in their own burrows, but major recruitment took place in late December and January. It is concluded that for C. bigelowi, the delay of recruitment into the winter months with low predation pressure and the large offspring size at this time are major advantages gained by extended parental care. C. bigelowi is host to the peritrich ciliate Cothurnia sp. on its gills, and during the summer months >70% of all amphipods had ciliates on their gills. Juveniles still living in their mother's burrows showed infestation rates similar to that of the parent; those of highly infested mothers were more heavily infested than those of "clean" mothers. Facilitated epibiont transmission during intimate and long-lasting (2 mo) parent-offspring associations may be a consequence of extended parental care. C1 Univ Maine, Darling Marine Ctr, Walpole, ME 04573 USA. RP Thiel, M (reprint author), Smithsonian Marine Stn, 5612 Old Dixie Highway, Ft Pierce, FL 34946 USA. EM thiel@sms.hboi.edu NR 49 TC 9 Z9 10 U1 2 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD AUG PY 1998 VL 132 IS 1 BP 107 EP 116 DI 10.1007/s002270050376 PG 10 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 118XK UT WOS:000075866100011 ER PT J AU Poe, S AF Poe, S TI The effect of taxonomic sampling on accuracy of phylogeny estimation: Test case of a known phylogeny SO MOLECULAR BIOLOGY AND EVOLUTION LA English DT Letter DE accuracy; known phylogeny; T7 bacteriophage; taxonomic sampling; phylogeny estimation ID TAXA; FOSSILS; TREES; EVOLUTION; PARSIMONY; NUMBERS C1 Univ Texas, Dept Zool, Austin, TX 78712 USA. Univ Texas, Texas Mem Museum, Austin, TX 78712 USA. RP Poe, S (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Div Amphibians & Reptiles, MRC 162, Washington, DC 20560 USA. NR 22 TC 39 Z9 39 U1 1 U2 3 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 1998 VL 15 IS 8 BP 1086 EP 1090 PG 5 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 109PR UT WOS:000075332400017 ER PT J AU Aldrich, PR Hamrick, JL Chavarriaga, P Kochert, G AF Aldrich, PR Hamrick, JL Chavarriaga, P Kochert, G TI Microsatellite analysis of demographic genetic structure in fragmented populations of the tropical tree Symphonia globulifera SO MOLECULAR ECOLOGY LA English DT Article DE demography; fragmentation; genetic diversity; genetic structure; microsatellites; tropical trees ID ACER-SACCHARUM; FOREST FRAGMENTATION; SEED DISPERSAL; DIPTEROCARPACEAE; CONSERVATION; FREQUENCIES; BIOLOGY; FLOW AB We developed genetic markers for three microsatellite loci in the tropical tree Symphonia globulifera and used them to examine the demographic genetic consequences of forest fragmentation. High levels of genetic variation were revealed in samples of adults, saplings, and seedlings. The more-variable loci exhibited less stability in allelic composition across sites and stages. The number of alleles per hectare (ha) of forest was similar when continuous forest plots were compared to plots from fragmented forest for all three stages. This pattern also held for the number of unique multilocus adult and sapling genotypes, but the number of unique seedling genotypes per ha of fragmented forest greatly exceeded expectations based on continuous forest data, probably due to the concentration of seeds into remnant forest patches by foraging bats. Significant inbreeding and genetic differentiation were most often associated with the fragmented forest and the seedlings. Finally, principal component analysis reaffirmed that a bottleneck, acting in concert with pre-existing genetic structure in the adults, had led to enhanced and rapid divergence in the seedlings following deforestation, a result that is of central interest for landscape management. C1 Univ Georgia, Dept Bot, Athens, GA 30605 USA. Univ Georgia, Dept Bot, Athens, GA 30605 USA. Univ Georgia, Dept Genet, Athens, GA 30605 USA. RP Aldrich, PR (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, NHB-166, Washington, DC 20560 USA. NR 44 TC 127 Z9 141 U1 0 U2 19 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD AUG PY 1998 VL 7 IS 8 BP 933 EP 944 DI 10.1046/j.1365-294x.1998.00396.x PG 12 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA 108HR UT WOS:000075260700001 PM 9711860 ER PT J AU Ward, SJ Macek, JH Ovchinnikov, SY AF Ward, SJ Macek, JH Ovchinnikov, SY TI Hidden crossing theory applied to positronium formation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT Workshop on Low Energy Positron and Positronium Physics CY JUL 15-18, 1997 CL UNIV NOTTINGHAM, NOTTINGHAM, ENGLAND HO UNIV NOTTINGHAM DE positronium formation; positron-hydrogen collisions; hidden crossing theory ID CLOSE-COUPLING CALCULATION; S-WAVE POSITRON; HYDROGEN SCATTERING; THRESHOLD IONIZATION; LOW ENERGIES; SECTIONS; COLLISIONS; IMPACT; ATOMS; CHANNEL AB The hidden crossing theory that employs the hyperspherical representation has been applied to Ps-formation in positron-hydrogen collisions in the Ore gap. S-, P- and D-wave cross-sections have been computed. For S-wave scattering, there occurs almost complete destructive interference between the two amplitudes that correspond to different paths leading to Ps-formation, However, for the D-wave there occurs almost complete constructive interference. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ N Texas, Dept Phys, Denton, TX 76203 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA USA. RP Ward, SJ (reprint author), Univ N Texas, Dept Phys, POB 305370, Denton, TX 76203 USA. RI Ovchinnikov, Serguei/C-4994-2014 NR 46 TC 4 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD AUG PY 1998 VL 143 IS 1-2 BP 175 EP 183 DI 10.1016/S0168-583X(97)00989-0 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 113UY UT WOS:000075573100025 ER PT J AU Wurth, MKR Winter, K Korner, C AF Wurth, MKR Winter, K Korner, C TI Leaf carbohydrate responses to CO2 enrichment at the top of a tropical forest SO OECOLOGIA LA English DT Article DE Anacardium; Cecropia; Ficus; elevated CO2; light climate ID ELEVATED ATMOSPHERIC CO2; PLANT-RESPONSES; CARBON; TREES; GROWTH; MODEL AB The accumulation of non-structural leaf carbohydrates is one of the most consistent plant responses to elevated CO2. It has been found in both fast-and slow-growing plants and is largely independent of the duration of exposure. Changes in leaf quality are thus to be expected, irrespective of other plant responses to atmospheric CO2 enrichment. However, there is no experimental evidence from tropical forests, the biome with the largest biomass carbon pool. Here we report in situ mesophyll responses of mature tropical trees to a doubling of CO2, Individually CO2-enriched leaves on 25 to 35-m-tall forest trees living at 26-35 degrees C can be assumed to experience little sink limitation, and so, may be expected to exhibit no or very little carbohydrate accumulation. We tested this hypothesis using the leaf cup method on leaves accessible via the canopy crane of the Smithsonian Tropical Research Institute in a semi-deciduous tropical forest in Panama. We also investigated the influence of the leaf-specific light regime, another possible environmental determinant of leaf carbon gain and mobile leaf carbohydrates. Total non-structural carbohydrates (TNC) reached a new steady state concentration after less than 4 days of exposure to twice ambient CO2 concentration. Against expectation, all four tree species investigated (Anacardium excelsum, Cecropia longipes, C. peltata, Ficus insipida) accumulated significant amounts of TNC (+41 to +61%) under elevated CO2. The effect was stronger at the end of the daylight period (except for Ficus), but was still significant in all four species at the end of the dark period. In contrast, neither artificial nor natural shading affected leaf TNC. Taken together, these observations suggest that TNC accumulation reflects a mesophyll-bound tissue response specific to elevated CO2, presumably unrelated to sink limitations. Thus, leaves of tropical forests seem not to be an exception, and will most likely contain more non-structural carbohydrates in a CO2-rich world. C1 Univ Basel, Inst Bot, CH-4056 Basel, Switzerland. Smithsonian Trop Res Inst, Balboa, Panama. RP Korner, C (reprint author), Univ Basel, Inst Bot, Schonbeinstr 6, CH-4056 Basel, Switzerland. RI Korner, Christian/B-6592-2014 NR 22 TC 33 Z9 36 U1 2 U2 13 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0029-8549 J9 OECOLOGIA JI Oecologia PD AUG PY 1998 VL 116 IS 1-2 BP 18 EP 25 PG 8 WC Ecology SC Environmental Sciences & Ecology GA 118JR UT WOS:000075835200003 PM 28308524 ER PT J AU Lovelock, CE Winter, K Mersits, R Popp, M AF Lovelock, CE Winter, K Mersits, R Popp, M TI Responses of communities of tropical tree species to elevated CO2 in a forest clearing SO OECOLOGIA LA English DT Article DE elevated CO2; biomass allocation; successional status; leaf chemistry; tropical forest tree species ID ATMOSPHERIC CARBON-DIOXIDE; PLANT FUNCTIONAL TYPES; SOIL NUTRIENT; DECOMPOSITION RATES; GROWTH ENHANCEMENT; ORGANIC-MATTER; LEAF-LITTER; RAIN-FOREST; ENRICHMENT; ECOSYSTEMS AB Communities of ten species of tropical forest tree seedlings from three successional classes were grown at ambient and elevated CO2 in large open-top chambers on the edge of a forest in Panama. Communities grew from 20 cm to approximately 2 m in height in 6 months. No enhancements in plant biomass accumulation occurred under elevated CO2 either in the whole communities or in growth of individual species. Reductions in leaf area index under elevated CO2 were observed, as were decreases in leaf nitrogen concentrations and increases in the C:N ratio of leaf tissue. Species tended to respond individualistically to elevated CO2, but some generalizations of how successional groupings responded could be made. Early and mid-successional species generally showed greater responses to elevated CO2 than late-successional species, particularly with respect to increases in photosynthetic rates and leaf starch concentrations, and reductions in leaf area ratio. Late-successional species showed greater increases in C:N ratios in response to elevated CO2 than did other species. Our results indicate that there may not be an increase in the growth of regenerating tropical forest under elevated CO2, but that there could be changes in soil nutrient availability because of reductions in leaf tissue quality, particularly in late-successional species. C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Vienna, Inst Plant Physiol, A-1091 Vienna, Austria. RP Lovelock, CE (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. EM lovelock@serc.si.edu RI Popp, Marianne/E-7559-2012; Lovelock, Catherine/G-7370-2012 OI Lovelock, Catherine/0000-0002-2219-6855 NR 70 TC 31 Z9 38 U1 0 U2 11 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0029-8549 J9 OECOLOGIA JI Oecologia PD AUG PY 1998 VL 116 IS 1-2 BP 207 EP 218 DI 10.1007/s004420050581 PG 12 WC Ecology SC Environmental Sciences & Ecology GA 118JR UT WOS:000075835200025 PM 28308528 ER PT J AU Frazin, RA AF Frazin, RA TI Optical path stability and fringe tracking in optical stellar interferometry SO OPTICS COMMUNICATIONS LA English DT Article DE statistical optics; optical stellar interferometry; fringe tracking ID GROUP-DELAY TRACKING; LOW LIGHT LEVELS; PARAMETER-ESTIMATION; NOISE AB We analyze the problems of fringe pattern estimation in optical stellar interferometry that are associated with optical path errors. Our first finding is that an optimal fringe tracking system must track with path length errors of less than about one-eighth of the coherence length. The second is that if phase closure estimation is to be achieved at the lowest possible light levels, the time scale of fringe wander must not be less than about 10% of the total observation time. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA. RP Frazin, RA (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. RI Frazin, Richard/J-2625-2012 NR 22 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD AUG 1 PY 1998 VL 153 IS 4-6 BP 323 EP 330 DI 10.1016/S0030-4018(98)00250-8 PG 8 WC Optics SC Optics GA 112FC UT WOS:000075482600026 ER PT J AU Yan, ZC Babb, JF AF Yan, ZC Babb, JF TI Long-range interactions of metastable helium atoms SO PHYSICAL REVIEW A LA English DT Article ID QUADRUPOLE POLARIZABILITIES; DIPOLE POLARIZABILITIES; DISPERSION COEFFICIENTS; STATES; FORCE; S-1; GAS AB The electric dipole, quadrupole, and octupole polarizabilities of a helium atom and the associated dispersion coefficients for the interaction of two helium atoms are calculated for the atomic n = 2 singlet and triplet states, respectively, He(2 S-1) and He(2 S-3). The calculations utilize highly accurate, variationally determined, wave functions composed of doubled basis sets. The effects of retardation due to the finite speed of light are calculated for the dispersion potentials of two He(2 S-1) or two He(2 S-3) atoms and for the atom-surface interaction potentials of a He(2 S-1) or a He(2 S-3) atom with a perfectly conducting or a dielectric wall. [S1050-2947(98)06208-8]. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Yan, ZC (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. RI Yan, Zong-Chao/F-6668-2014; OI Babb, James/0000-0002-3883-9501 NR 31 TC 53 Z9 53 U1 3 U2 10 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 1998 VL 58 IS 2 BP 1247 EP 1252 DI 10.1103/PhysRevA.58.1247 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 110NA UT WOS:000075386200056 ER PT J AU Kurtz, MJ Mink, DJ AF Kurtz, MJ Mink, DJ TI RVSAO 2.0: Digital redshifts and radial velocities SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID SPECTROSCOPIC BINARIES; DISPERSIONS; GALAXIES; SPECTRA; SLICE; IRAF AB RVSAO is a set of programs to obtain redshifts and radial velocities from digital spectra. RVSAO operates in the IRAF environment. The heart of the system is xcsao, which implements the cross-con-elation method and is a direct descendant of the system built by Tonry & Davis. emsao uses intelligent heuristics to search for emission lines in spectra, and then fits them to obtain a redshift. sumspec shifts and sums spectra to build templates for cross-correlation. linespec builds synthetic spectra given a list of spectral lines. bcvcorr corrects velocities for the motion of the Earth. We discuss in detail the parameters necessary to run xcsao and emsao properly. We discuss the reliability and error associated with xcsao-derived redshifts. We develop an internal error estimator, and we show how large, stable surveys can be used to develop more accurate error estimators. We also develop a new methodology for building spectral templates for galaxy redshifts, using the new templates for the FAST spectrograph as an example. We show how to obtain correlation velocities using emission-line templates. Emission-line correlations ate substantially more efficient than the previous standard technique, automated emission-line fitting. Using this machinery, the blunder rate for redshift measurements can be kept near zero. the automation rate for FAST spectra is similar to 95%. We use emsao to measure the instrumental zero-point offset and instrumental stability of the Z-Machine and FAST spectrographs. We compare the use of RVSAO with new methods, which use singular value decomposition and chi(2) fitting techniques, and conclude that the methods we use are either equal or superior. We show that a two-dimensional spectral classification of galaxy spectra can be developed using our emission- and absorption-line templates as physically orthogonal basis vectors. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kurtz, MJ (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 305 Z9 305 U1 0 U2 4 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD AUG PY 1998 VL 110 IS 750 BP 934 EP 977 DI 10.1086/316207 PG 44 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 113WW UT WOS:000075577700009 ER PT J AU Nowicke, JW Takahashi, M Webster, GL AF Nowicke, JW Takahashi, M Webster, GL TI Pollen morphology, exine structure and systematics of Acalyphoideae (Euphorbiaceae) - Part 1. Tribes Clutieae (Clutia), Pogonophoreae (Pogonophora), Chaetocarpeae (Chaetocarpus, Trigonopleura), Pereae (Pera), Cheiloseae (Cheilosa, Neoscortechinia), Erismantheae pro parte (Erismanthus, Moultonianthus), Dicoelieae (Dicoelia), Galearieae (Galearia, Microdesmis, Panda) and Ampereae (Amperea, Monotaxis) SO REVIEW OF PALAEOBOTANY AND PALYNOLOGY LA English DT Article DE pollen; Euphorbiaceae; exine structure; systematics ID ULTRASTRUCTURE AB This is the first paper of an extensive study of pollen morphology and exine structure of the Euphorbiaceae. To date, the pollen of more than 600 species has been examined, most of them in transmission electron microscopy as well as light microscopy and scanning electron microscopy. Pollen of Acalyphoideae, tribes Clutieae, Pogonophoreae, Chaetocarpeae, Pereae, Cheiloseae, Erismantheae pro parte, Dicoelieae, Galearieae, and Ampereae is described, documented by electron micrographs, and the systematic implications of the data are discussed. Almost all members of the above tribes have pollen that is 3-corporate in which the endoaperture frequently has well-defined polar margins but diffuse lateral ones. The tectum and exine structure are more variable. Pollen of Clutia has branched columellae and a tectum in which the 'floors' of the lumina are formed not by the foot layer but by the fusion of the distal tips of columellae. Pollen of Pogonophora has large columellae and a thick punctate tectum, characteristics that are shared with Trigonopleura, a genus assigned to Chaetocarpeae. The genus Chaetocarpus has pollen with small columellae and microrugulose tecta. Most species of Pera have thin exines characterized by small columellae; pollen of P. arborea is intectate; pollen of P. distichophylla is thick-walled with massive columellae and a thick foot layer-endexine. Grains of Cheilosa and Neoscortechinia (Cheiloseae) have echinate tecta, a distinction reinforced by an almost identical exine structure. The single species of Moultonianthus (Erismantheae) has pollen with reticulate tecta and well-developed columellae while Erismanthus has a punctate tectum and small irregular columellae. Pollen of Dicoelia has a weakly suprareticulate tectum and columellae that are poorly differentiated from a channeled tectum. Grains of Galearia and Microdesmis have thin exines with deeply punctate tecta in contrast to pollen of the third genus of Galearieae, Panda, which has a thick exine with and a reticulate tectum. The two genera of Ampereae, Amperea and Monotaxis, have pollen with reticulate tecta, but the former genus has large elongate columellae and partially covered lumina, and the latter has smaller columellae and an unmodified reticulate tectum. The data from exine structure: support the monogeneric concept of Clutieae; show that Pogonophora is not closely related to Clutia, suggest that Trigonopleura may be more closely related to Pogonophoreae than to Chaetocarpeae; are anomalously, sometimes conspicuously, variable within Pei-a; support the present concept of Cheiloseae and the close relationship between and the isolation of Cheilosa and Neoscortechinia; support a close relationship between Galearia and Microdesmis, but not with Panda; suggest that the biovulate genus Dicoelia is isolated in the uniovulate Acalyphoideae; and indicate that the similarity in SEM between pollen of Amperea and that of Monotaxis is superficial, and that the two genera are not as closely related as previously thought. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, NHB 166, Washington, DC 20560 USA. Kagawa Univ, Dept Biol, Takamatsu, Kagawa 760, Japan. Univ Calif Davis, Herbarium, Plant Biol Sect, Davis, CA 95616 USA. RP Nowicke, JW (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, NHB 166, Washington, DC 20560 USA. NR 29 TC 22 Z9 27 U1 2 U2 5 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 1998 VL 102 IS 3-4 BP 115 EP 152 DI 10.1016/S0034-6667(98)00018-9 PG 38 WC Plant Sciences; Paleontology SC Plant Sciences; Paleontology GA 107FA UT WOS:000075195400001 ER PT J AU Manchester, SR Dilcher, DL Wing, SL AF Manchester, SR Dilcher, DL Wing, SL TI Attached leaves and fruits of myrtaceous affinity from the middle Eocene of Colorado SO REVIEW OF PALAEOBOTANY AND PALYNOLOGY LA English DT Article DE palaeobotany; Eocene; Myrtaceae; Colorado; Green River Formation; leaves; fruits AB A new myrtaceous genus, Syzygioides Manchester, Dilcher et Wing, gen. nov., is established based upon compressed twigs showing the attachment of leaves, with axillary panicles of flowers and fruits from the Eocene of the Rocky Mountain region. The new combination Syzygioides americana (Lesquereux) Manchester, Dilcher et Wing, comb. nov. applies to leaves that formerly were attributed to Eucalyptus and Eugenia. The opposite, decussately arranged leaves are similar in architecture to those of extant Syzygium fluviatilis (Hemsley) Merrill et Ferry and S. jambos (L.) Alston, but the attached leathery fruits, with incurved persistent calyx and short capitate stigmas, are unlike those of extant Eucalyptus, Syzygium, Eugenia and other extant genera. Syzygioides americana first appears in the Lower Eocene of the Rocky Mountain region and is common in the Middle Eocene. The improved understanding of this fossil shows the presence of an extinct myrtaceous genus in the Eocene and demonstrates the need for caution in attempting to identify isolated fossil leaves to extant genera of the Myrtaceae. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Florida, Florida Museum Nat Hist, Dept Nat Sci, Gainesville, FL 32611 USA. Smithsonian Inst, Museum Natl Hist Nat, Dept Paleobiol, Washington, DC 20560 USA. RP Manchester, SR (reprint author), Univ Florida, Florida Museum Nat Hist, Dept Nat Sci, Gainesville, FL 32611 USA. EM steven@flmnh.ufl.edu OI Wing, Scott/0000-0002-2954-8905 NR 25 TC 20 Z9 20 U1 0 U2 2 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 1998 VL 102 IS 3-4 BP 153 EP 163 DI 10.1016/S0034-6667(97)00056-0 PG 11 WC Plant Sciences; Paleontology SC Plant Sciences; Paleontology GA 107FA UT WOS:000075195400002 ER PT J AU Ball, AS Drake, BG AF Ball, AS Drake, BG TI Stimulation of soil respiration by carbon dioxide enrichment of marsh vegetation SO SOIL BIOLOGY & BIOCHEMISTRY LA English DT Article ID ELEVATED ATMOSPHERIC CO2; NITROGEN; PLANTS; INSITU C1 Univ Essex, Dept Biol Sci, Colchester CO4 3SQ, Essex, England. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Ball, AS (reprint author), Univ Essex, Dept Biol Sci, Wivenhoe Pk, Colchester CO4 3SQ, Essex, England. NR 18 TC 23 Z9 34 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-0717 J9 SOIL BIOL BIOCHEM JI Soil Biol. Biochem. PD AUG PY 1998 VL 30 IS 8-9 BP 1203 EP 1205 DI 10.1016/S0038-0717(97)00253-8 PG 3 WC Soil Science SC Agriculture GA ZY151 UT WOS:000074591400027 ER PT J AU Nicolson, DH AF Nicolson, DH TI First taxonomic assessment of George Forster's botanical artwork at Gotha (Thuringia, Germany) SO TAXON LA English DT Article AB The three repositories of botanical art of G. Forster, artist and author of works underlying South Pacific botany, are reviewed. Identifications are given of the 6 paintings and 78 drawings held in Gotha. C1 Smithsonian Inst, Natl Museum Nat Hist, Bot Dept MRC166, Washington, DC 20560 USA. RP Nicolson, DH (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Bot Dept MRC166, Washington, DC 20560 USA. NR 20 TC 1 Z9 1 U1 0 U2 1 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 1998 VL 47 IS 3 BP 581 EP 592 DI 10.2307/1223579 PG 12 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA 114KC UT WOS:000075607100002 ER PT J AU Rogers, PG Zuber, MT AF Rogers, PG Zuber, MT TI Tectonic evolution of Bell Regio, Venus: Regional stress, lithospheric flexure, and edifice stresses SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SURFACE DEFORMATION; KILAUEA VOLCANO; CALDERA; MECHANICS; GRAVITY; MODEL; DEPTH; MARS; TERRESTRIAL; FERNANDINA AB In order to understand the relationship between volcanic and tectonic processes and the stress state in the lithosphere of Venus, we analyzed the stress environments and resulting tectonic features associated with the major volcanic edifices in Bell Regio, using Magellan synthetic aperture radar (SAR) images and altimeter measurements of topography. The major volcanoes of Bell Regio, Tepev Mons and Nyx Mons, exhibit tectonic characteristics that are unique relative to other volcanic edifices on Venus, The most prominent distinction is the lack of large rift zones within the over all highland uplift, which characterize many other highland rises on Venus. Also, previous studies have determined that many large Venus volcanoes exhibit radial tectonic structures on their flanks but generally lack the circumferential graben which surround volcanoes on Earth and Mars, Tepev and Nyx Montes exhibit both the radial tectonic features associated with other Venusian edifices and numerous concentric graben. Nyx Mons implies a more distributed magmatic system by its broad shape, radial chains of pit craters, and expansive flow fields, whereas Tepev Mons is a more centralized volcanic system, with limited associated long flows. We investigate the regional stresses associated with Bell Regio and structural features believed to be a consequence of lithospheric flexure due to volcanic loading, modeling both Nyx Mons and Tepev Mons as axisymmetric loads with Gaussian mass distributions on an elastic plate. The relationship between the tectonic features surrounding Tepev Mons and stresses associated with magma chamber inflation are also examined through finite element analysis. Using topography data to model the shape of the volcano, we determine that a horizontally ellipsoidal or tabular reservoir at a range of depths from approximately 20 to 40 km can satisfy the locations of graben formation observed in Magellan images. These results imply a shift in volcanic style within Bell Regio from an early phase of broad, low shield formation to later steep-sided, more centralized edifice development, Such changes are consistent with an increase in the thickness of the lithosphere over time. C1 Rand Corp, Washington, DC USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Rogers, PG (reprint author), Smithsonian Inst, MRC 315, Washington, DC 20560 USA. EM rogers@ceps.nasm.edu; zuber@tharsis.gsfc.nasa.gov NR 61 TC 6 Z9 6 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUL 25 PY 1998 VL 103 IS E7 BP 16841 EP 16853 DI 10.1029/98JE00585 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 138KA UT WOS:000076970000005 ER PT J AU Fiore, F Matt, G Cappi, M Elvis, M Leighly, KM Nicastro, F Piro, L Siemiginowska, A Wilkes, BJ AF Fiore, F Matt, G Cappi, M Elvis, M Leighly, KM Nicastro, F Piro, L Siemiginowska, A Wilkes, BJ TI ASCA observations of two steep soft X-ray quasars SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE line : formation; line : identification; galaxies : individual : NAB 0205+024; galaxies : individual : PG 1244+026; galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; ACCRETION DISKS; ULTRAVIOLET; SPECTRUM; BUMP; PLASMA; HOT AB Steep soft X-ray (0.1-2 keV) quasars share several unusual properties: narrow Balmer lines, strong Fell emission, large and fast X-ray variability, and a rather steep 2-10 keV spectrum. These intriguing objects have been suggested to be the analogues of Galactic black hole candidates in the high, soft state. We present here results from ASCA observations for two of these quasars: NAB 0205 + 024 and PG 1244 + 026. Both objects show similar variations (factor of similar to 2 in 10 ks), despite a factor of similar to 10 difference in the 0.5-10 keV luminosity (7.3 x 10(43) erg s(-1) for PG 1244 + 026 and 6.4x10(44) erg s(-1) for NAB 0205 +024, assuming isotropic emission, H-o = 50.0 and q(o) = 0.0). The X-ray continuum of the two quasars flattens by 0.5-1 going from the 0.1-2 keV band towards higher energies, strengthening recent results on another half-dozen steep soft X-ray active galactic nuclei. PG 1244 + 026 shows a significant feature in the '1-keV' region, which can be described either as a broad emission line centred at 0.95 keV (quasar frame) or as edge or Line absorption at 1.17 (1.22) keV. The line emission could be a result of reflection from a highly ionized accretion disc, in line with the view that steep soft X-ray quasars are emitting close to the Eddington luminosity. Photoelectric edge absorption or resonant line absorption could be produced by gas outflowing at a large velocity (0.3-0.6 c). C1 Osservatorio Astron Roma, I-00044 Monte Porzio Catone, Italy. SAX Sci Data Ctr, I-00131 Rome, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Roma Tre, Dipartimento Fis, I-00146 Rome, Italy. CNR, ITESRE, I-40129 Bologna, Italy. RIKEN, Cosm Radiat Lab, Wako, Saitama 351, Japan. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. CNR, Ist Astrofis Spaziale, I-00044 Frascati, Italy. RP Fiore, F (reprint author), Osservatorio Astron Roma, Via Osservatorio, I-00044 Monte Porzio Catone, Italy. RI PIRO, LUIGI/E-4954-2013; Cappi, Massimo/F-4813-2015; OI PIRO, LUIGI/0000-0003-4159-3984; Cappi, Massimo/0000-0001-6966-8920; Nicastro, Fabrizio/0000-0002-6896-1364; Wilkes, Belinda/0000-0003-1809-2364; Fiore, Fabrizio/0000-0002-4031-4157 NR 47 TC 35 Z9 36 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 1998 VL 298 IS 1 BP 103 EP 113 DI 10.1046/j.1365-8711.1998.01721.x PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 108CE UT WOS:000075247800015 ER PT J AU West-Eberhard, MJ AF West-Eberhard, MJ TI Evolution in the light of developmental and cell biology, and vice versa SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Editorial Material ID PHENOTYPIC PLASTICITY; SELECTION; EVOLVABILITY; VARIABILITY; ADAPTATIONS C1 Smithsonian Trop Res Inst, Unit 2511, APO, AA 34020 USA. RP West-Eberhard, MJ (reprint author), Smithsonian Trop Res Inst, Unit 2511, APO, AA 34020 USA. NR 44 TC 55 Z9 59 U1 1 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 JUL 21 PY 1998 VL 95 IS 15 BP 8417 EP 8419 DI 10.1073/pnas.95.15.8417 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 103EA UT WOS:000075143900002 PM 9671691 ER PT J AU Doebeli, M Knowlton, N AF Doebeli, M Knowlton, N TI The evolution of interspecific mutualisms SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID TIT-FOR-TAT; PRISONERS-DILEMMA; COOPERATION; CHAOS; SYMBIOSIS; BEHAVIOR; MODEL; GAME AB Interspecific mutualisms are widespread, but how they evolve is not clear. The Iterated Prisoner's Dilemma is the main theoretical tool to study cooperation, but this model ignores ecological differences between partners and assumes that amounts exchanged cannot themselves evolve. A more realistic model incorporating these features shows that strategies that succeed with fixed exchanges (e.g., Tit-for-Tat) cannot explain mutualism when exchanges vary because the amount exchanged evolves to 0. For mutualism to evolve, increased investments in a partner must yield increased returns, and spatial structure in competitive interactions is required. Under these biologically plausible assumptions, mutualism evolves with surprising ease. This suggests that, contrary to the basic premise of past theoretical analyses, overcoming a potential host's initial defenses may be a bigger obstacle for mutualism than the subsequent recurrence and spread of noncooperative mutants. C1 Univ Basel, Inst Zool, CH-4051 Basel, Switzerland. Smithsonian Trop Res Inst, Balboa, Panama. RP Doebeli, M (reprint author), Univ Basel, Inst Zool, Rheinsprung 9, CH-4051 Basel, Switzerland. RI Doebeli, Michael/D-5391-2012 NR 29 TC 280 Z9 291 U1 4 U2 74 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 JUL 21 PY 1998 VL 95 IS 15 BP 8676 EP 8680 DI 10.1073/pnas.95.15.8676 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 103EA UT WOS:000075143900048 PM 9671737 ER PT J AU Wojdowski, P Clark, GW Levine, AM Woo, JW Zhang, SN AF Wojdowski, P Clark, GW Levine, AM Woo, JW Zhang, SN TI Quasi-periodic occultation by a precessing accretion disk and other variabilities of SMC X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : general; galaxies : Magellanic Clouds; pulsars : individual (SMC X-1) ID SMALL MAGELLANIC CLOUD; X-RAY SOURCES; ROSAT OBSERVATIONS; PROPORTIONAL COUNTER; WIND DYNAMICS; TURN-ON; GINGA; HERCULES-X-1; SPECTROSCOPY; DISCOVERY AB We have investigated the variability of the binary X-ray pulsar SMC X-l in data from several X-ray observatories. We confirm the similar to 60 day cyclic variation of the X-ray flux in the long-term monitoring data from the RXTE and CGRO observatories. X-ray light curves and spectra from the ROSAT, Ginga, and ASCA observatories show that the uneclipsed flux varies by as much as a factor of 20 between a high-flux state when 0.71 s pulses are present and a low-flux state when pulses are absent. In contrast, during eclipses when the X-rays consist of radiation scattered from circumsource matter, the fluxes and spectra in the high and low states are approximately the same. These observations prove that the low state of SMC X-1 is not caused by a reduction in the intrinsic luminosity of the source or a spectral redistribution thereof, but rather by a quasi-periodic blockage of the line of sight, most likely by a precessing tilted accretion disk. In each of two observations in the midst of low states a brief increase in the X-ray flux and reappearance of 0.71 s pulses occurred near orbital phase 0.2. A similar brief flux increase near orbital phase 0.2 was observed during a low-state observation that did not have sufficient time resolution to detect 0.71 s pulses. These brief increases result from an opening of the line of sight to the pulsar that may be caused by wobble in the precessing accretion disk. The records of spin-up of the neutron star and decay of the binary orbit are extended during 1991-1996 by pulse-timing analysis of ROSAT, ASCA, and RXTE PCA data. The pulse profiles in various energy ranges from 0.1 to greater than 21 keV are well represented as a combination of a pencil beam and a fan beam. Finally, there is a marked difference between the power spectra of random fluctuations in the high-state data from the RXTE PCA below and above 3.4 keV. In the higher energy range the spectrum has a sharp break at 3.3 Hz, with fitted power-law indices of 0.45 and 1.76 below and above the break. No break is evident in the power spectrum below 3.4 keV, and the fitted power-law index is 0.51. In both spectra there is a positive deviation from the fitted power law around 0.06 Hz that may be quasi-periodic oscillation. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Wojdowski, P (reprint author), MIT, Dept Phys, Cambridge, MA 02139 USA. NR 56 TC 70 Z9 70 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1998 VL 502 IS 1 BP 253 EP 264 DI 10.1086/305893 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 151WH UT WOS:000077743300022 ER PT J AU Kallman, T Boroson, B Vrtilek, SD AF Kallman, T Boroson, B Vrtilek, SD TI Simultaneous Hubble Space Telescope/Rossi X-Ray Timing Explorer observations of Scorpius X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; stars : individual (Scorpius X-1); ultraviolet : stars; X-rays : stars ID ACCRETION DISKS; BLACK-HOLES; EMISSION; IUE; ULTRAVIOLET; ABSORPTION; DISTANCE; CORONAE; SPECTRA; LINES AB Scorpius X-1 is the brightest extrasolar point source of X-rays and may serve as a prototype for low-mass X-ray binaries as a class. It has been suggested that the UV and optical emission arise as a result of reprocessing of X-rays and that a likely site for such reprocessing is an accretion disk around the X-ray source. If UV and optical emission are enhanced by the reprocessing of X-rays, the X-ray variability may be manifest in UV emission. We test this by using high temporal resolution UV data obtained simultaneously with high temporal resolution X-ray data collected by the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope and by the X-Ray Timing Explorer. We analyze the variability behavior of the UV spectrum and of the X-rays, and we also measure the properties of the emission-line profiles as viewed at high resolution (resolving power similar or equal to 25,000) with the echelle gratings. The variability behavior does not provide direct support for the reprocessing scenario, although the correlated variability between UV and X-rays does not conflict with this hypothesis. Furthermore, the emission-line profiles do not fit with simple models for disk emission lines. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kallman, T (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM tim@xstar.gsfc.nasa.gov; bboroson@riva.harvard.edu; svrtilek@cfa.harvard.edu NR 49 TC 10 Z9 10 U1 0 U2 0 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 20 PY 1998 VL 502 IS 1 BP 441 EP 454 DI 10.1086/305873 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 151WH UT WOS:000077743300038 ER PT J AU Szalewicz, K Jeziorski, B AF Szalewicz, K Jeziorski, B TI Comment on "On the importance of the fragment relaxation energy terms in the estimation of the basis set superposition error correction to the intermolecular interaction energy" [J Chem Phys 104, 8821 (1996)] SO JOURNAL OF CHEMICAL PHYSICS LA English DT Letter ID FUNCTION COUNTERPOISE METHOD; AB-INITIO CALCULATIONS; GEOMETRY; DIMER; BOYS; HF; OH C1 Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Warsaw, Dept Chem, PL-02093 Warsaw, Poland. RP Szalewicz, K (reprint author), Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA. NR 19 TC 83 Z9 85 U1 0 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 15 PY 1998 VL 109 IS 3 BP 1198 EP 1200 DI 10.1063/1.476667 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FN UT WOS:000075255500042 ER PT J AU Turok, N Pen, UL Seljak, U AF Turok, N Pen, UL Seljak, U TI Scalar, vector, and tensor contributions to CMB anisotropies from cosmic defects SO PHYSICAL REVIEW D LA English DT Article ID MICROWAVE AB Recent work has emphasised the importance of vector and tensor contributions to the large scale microwave anisotropy fluctuations produced by cosmic defects. In this paper we provide a general discussion of these contributions, and how their magnitude is constrained by the fundamental assumptions of causality, scaling, and statistical isotropy. We discuss an analytic model which illustrates and explains how the ratios of isotropic and anisotropic scalar, vector and tensor stress-energy sources are determined. This provides a check of the results from large scale numerical simulations, confirming the numerical finding that vector and tensor modes provide substantial contributions to the large angle anisotropies. We show that the qualitative features of the stress-energy tensor carry over to the microwave background anisotropies. This leads to a suppression of the scalar normalization and consequently of the Doppler peaks. [S0556-2821(98)03514-0]. C1 Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. Harvard Coll Observ, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Turok, N (reprint author), Univ Cambridge, Dept Appl Math & Theoret Phys, Silver St, Cambridge CB3 9EW, England. EM N.G.Turok@damtp.cam.ac.uk; upen@cfa.harvard.edu; useljak@cfa.harvard.edu NR 10 TC 50 Z9 50 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 JUL 15 PY 1998 VL 58 IS 2 AR 023506 DI 10.1103/PhysRevD.58.023506 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 106ZG UT WOS:000075180900014 ER PT J AU Zaldarriaga, M Seljak, U AF Zaldarriaga, M Seljak, U TI Gravitational lensing effect on cosmic microwave background polarization SO PHYSICAL REVIEW D LA English DT Article ID FLUCTUATIONS; ANISOTROPIES; RADIATION; UNIVERSE AB We investigate the effect of gravitational lensing by matter distribution in the universe on the cosmic microwave background polarization power spectra and temperature-polarization cross-correlation spectrum. As in the case of the temperature spectrum, gravitational lensing leads to a smoothing of narrow features and the enhancement of power on the damping tail of the power spectrum. Because the acoustic peaks in polarization spectra are narrower than in the temperature spectrum the smoothing effect is significantly larger and can reach up to 10% for l<1000 and even more above that. A qualitatively new feature is the generation of B type polarization even when only E is intrinsically present, such as in the case of pure scalar perturbations. This may be directly observed with Planck and other future small scale polarization experiments. The gravitational lensing effect is incorporated in the new version (2.4) of the CMBFAST code. [S0556-2821(98)05214-X]. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Zaldarriaga, M (reprint author), MIT, Dept Phys, Cambridge, MA 02139 USA. NR 21 TC 266 Z9 266 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 EI 1550-2368 J9 PHYS REV D JI Phys. Rev. D PD JUL 15 PY 1998 VL 58 IS 2 AR 023003 DI 10.1103/PhysRevD.58.023003 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 106ZG UT WOS:000075180900006 ER PT J AU Churazov, E Sunyaev, R Gilfanov, M Forman, W Jones, C AF Churazov, E Sunyaev, R Gilfanov, M Forman, W Jones, C TI The 6.4-keV fluorescent iron line from 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 X-RAY SOURCES; ABSORBING MATTER; PERSEUS CLUSTER; GALAXIES; GAS; EMISSION; ACCRETION; EINSTEIN; SOLAR; COLD AB The fate of the cooling gas in the central regions of rich clusters of galaxies is not well understood. In one plausible scenario clouds of atomic or molecular gas are formed. However the mass of the cold gas, inferred from measurements of low-energy X-ray absorption, is hardly consistent with the absence of powerful CO or 21-cm emission lines from the cooling flow region. Among the factors which may affect the detectability of the cold clouds are their optical depth, shape and covering fraction. Thus, alternative methods to determine the mass in cold clouds, which are less sensitive to these parameters, are important. For the inner region of the cooling flow (e.g. within a radius of similar to 50-100 kpc) the Thomson optical depth of the hot gas in a massive cooling flow can be as large as similar to 0.01. Assuming that the cooling time in the inner region is few times shorter than the lifetime of the cluster, the Thomson depth of the accumulated cold gas can be accordingly higher (if most of the gas remains in the form of clouds). The illumination of the cold clouds by the X-ray emission of the hot gas should lead to the appearance of a 6.4-keV iron fluorescent line, with an equivalent width proportional to tau(T). The equivalent width only weakly depends on the detailed properties of the clouds, e.g. on the column density of individual clouds, as long as the column density is less than a few 10(23) cm(-2). Another effect also associated exclusively with the cold gas is a flux in the Compton shoulder of bright X-ray emission lines. It also scales linearly with the Thomson optical depth of the cold gas. With the new generation of X-ray telescopes, combining large effective area and high spectral resolution, the mass of the cold gas in cooling flows (and its distribution) can be measured. C1 MPI Astrophys, D-85740 Garching, Germany. Moscow Space Res Inst, Moscow 117810, Russia. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Churazov, E (reprint author), MPI Astrophys, Karl Schwarzschild Str 1, D-85740 Garching, Germany. RI Churazov, Eugene/A-7783-2013; OI Forman, William/0000-0002-9478-1682 NR 38 TC 6 Z9 6 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 11 PY 1998 VL 297 IS 4 BP 1274 EP 1278 DI 10.1046/j.1365-8711.1998.01685.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 105DP UT WOS:000075057700031 ER PT J AU Perna, R Loeb, A AF Perna, R Loeb, A TI Identifying the environment and redshift of gamma-ray burst afterglows from the time dependence of their absorption spectra SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; gamma rays : bursts AB The discovery of gamma-ray burst (GRB) afterglows revealed a new class of variable sources at optical and radio wavelengths. At present, the environment and precise redshift of the detected afterglows are still unknown. We show that if a GRB source resides in a compact (less than or similar to 100 pc) gas-rich environment, the afterglow spectrum will show time-dependent absorption features due to the gradual ionization of the surrounding medium by the afterglow radiation. Detection of this time dependence can be used to constrain the size and density of the surrounding gaseous system. For example, the Mg II absorption line detected in GRB 970508 should have weakened considerably during the first month if the absorption occurred in a gas cloud of size less than or similar to 100 pc around the source. The time-dependent H I or metal absorption features provide a precise determination of the GRB redshift. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Perna, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 34 TC 102 Z9 102 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1998 VL 501 IS 2 BP 467 EP 472 DI 10.1086/305865 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101DB UT WOS:000074853400004 ER PT J AU Giampapa, MS Prosser, CF Fleming, TA AF Giampapa, MS Prosser, CF Fleming, TA TI X-ray activity in the open cluster IC 4665 SO ASTROPHYSICAL JOURNAL LA English DT Article DE open clusters and associations : individual (IC 4665); stars : evolution; stars : rotation; X-rays : stars ID LOW-MASS STARS; ALPHA-PERSEI CLUSTER; MAIN-SEQUENCE STARS; ROTATIONAL VELOCITIES; MAGNETIC ACTIVITY; BINARY FREQUENCY; STELLAR ROTATION; SPECTRAL TYPES; ROSAT SURVEY; PLEIADES AB We present the results of a joint ROSAT High Resolution Imager (HRI) and optical investigation of the open cluster IC 4665. The ROSAT data contains detections for 28 stellar sources in the held, including 22 cluster members and candidate members spanning the color range -0.18 less than or equal to (B-V)(0) less than or equal to 1.63 (similar to B3-M3). Upper limits are given for the remaining members (or candidate members) in the HRI field. Keck HIRES spectra have been obtained that yield radial and rotational velocity measures, respectively, for faint, low-mass candidate members located within the held of the ROSAT HRI observation. In addition, photometry of possible optical counterparts to previously uncataloged X-ray sources in the HRI held is presented. The trends in X-ray properties With B-V color in IC 4665 are found to be quite similar to that for other, more nearby young clusters such as the Pleiades and alpha Persei. In particular a maximum in normalized X-ray luminosity of log (L-X/L-bol) similar or equal to -3 is observed, beginning in the color range of(B-V)(0) = 0.7-0.8. This is similar to the corresponding color range among Pleiades members, in agreement with the earlier estimate by Presser & Giampapa that the age of IC 4665 is similar to the age of the Pleiades. The correlation of rotation and X-ray emission levels is consistent with that in other young clusters. Among the high-mass stars in IC 4665, five B stars are detected as X-ray sources. Of these, one is a spectroscopic binary while the remaining objects are apparently single stars. The level of intrinsic X-ray emission observed in the rapidly rotating (v sin i > 200 km s(-1)), single B stars is consistent with an origin due to shock heating of the ambient medium by radiatively driven, rotationally enhanced winds. On the basis of these observations and the results for other clusters, we argue that observed levels of X-ray emission in high-mass stars of log (L-X/L-bol) > - 6.0 are likely due to intrinsic emission associated with the B star itself rather than emission from a late-type secondary. Finally, our results suggest that the initial angular momentum distributions and the subsequent evolution of rotation, L-X, and (L-X/L-bol) occur in practically identical fashions in clusters with ages less than or similar to 100 Myr. C1 Natl Opt Astron Observ, Natl Solar Observ, Tucson, AZ 85726 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Giampapa, MS (reprint author), Natl Opt Astron Observ, Natl Solar Observ, POB 26732, Tucson, AZ 85726 USA. NR 63 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1998 VL 501 IS 2 BP 624 EP 642 DI 10.1086/305831 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101DB UT WOS:000074853400019 ER PT J AU Rots, AH Jahoda, K Macomb, DJ Kawai, N Saito, Y Kaspi, VM Lyne, AG Manchester, RN Backer, DC Somer, AL Marsden, D Rothschild, RE AF Rots, AH Jahoda, K Macomb, DJ Kawai, N Saito, Y Kaspi, VM Lyne, AG Manchester, RN Backer, DC Somer, AL Marsden, D Rothschild, RE TI Rossi X-ray timing explorer absolute timing results for the pulsars B1821-24 and B1509-58 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : general; pulsars : individual (PSR B1509-58, PSR B1821-24); radio continuum : stars; X-rays : stars ID CRAB PULSAR; PSR B1509-58; GAMMA-RAY; VELA; EPHEMERIDES AB Observations with the Rossi X-Ray Timing Explorer and the Jodrell Bank, Parkes, and Green Bank telescopes have enabled us to determine the time delay between radio and X-ray pulses in the two isolated pulsars B1821-24 and B1509-58. For the former we find that the narrow X-ray and radio pulse components are close to being coincident in time, with the radio peak leading by 0.02 period (60 +/- 20 mu s), while the wide X-ray pulse component lags the last of the two wider radio components by about 0.08 period. For the latter pulsar we find, using the standard value for the dispersion measure, that the X-ray pulse lags the radio by about 0.27 period, with no evidence for any energy dependence in the range 2-100 keV. However, uncertainties in the history of the dispersion measure for this pulsar make a comparison to previous results difficult. It is clear that there are no perceptible variations in either the lag or the dispersion measure at timescales of a year or less. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RIKEN, Inst Phys & Chem Res, Wako, Saitama 35101, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Space Res Ctr, Cambridge, MA 02139 USA. Univ Manchester, Dept Phys, Macclesfield SK11 9DL, Cheshire, England. CSIRO, Australia Telescope Natl Facil, Epping, NSW 2121, Australia. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, San Diego, CA 92093 USA. RP Rots, AH (reprint author), Harvard Smithsonian Ctr Astrophys, MS 81,60 Garden St, Cambridge, MA 02138 USA. RI Jahoda, Keith/D-5616-2012 NR 27 TC 60 Z9 61 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1998 VL 501 IS 2 BP 749 EP 757 DI 10.1086/305836 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101DB UT WOS:000074853400029 ER PT J AU van Ballegooijen, AA Cartledge, NP Priest, ER AF van Ballegooijen, AA Cartledge, NP Priest, ER TI Magnetic flux transport and the formation of filament channels on the Sun SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : filaments; Sun : magnetic fields ID SOLAR PROMINENCES; SUNSPOT CYCLE-21; CORONAL HOLES; FIELD; EVOLUTION; MODEL; REGIONS; ERUPTION; PATTERNS; ROTATION AB Observations of filaments and filament channels on the Sun indicate that the magnetic fields in these structures exhibit a large-scale organization: filament channels in the northern hemisphere predominantly have axial fields directed to the right when viewed from the positive polarity side of the channel (dextral orientation), while those in the south have axial fields directed to the left (sinistral orientation). In this paper we attempt to explain this pattern in terms of the most natural mechanism, namely, solar differential rotation acting on already emerged magnetic fields. We develop a model of global magnetic flux transport that includes the effects of differential rotation, meridional how, and magnetic diffusion on photospheric and coronal fields. The model is applied to National Solar Observatory/Kitt Peak data(1) on the photospheric magnetic flux distribution. We also present results from a simulation of solar activity over a period of two solar cycles, which gives a buildup of flux at the poles of a magnitude, in agreement with observations. We find that differential rotation acting on initially north-south oriented polarity inversion lines (PILs) does produce axial fields consistent with the observed hemispheric pattern. The fields associated with switchbacks in the PILs are predicted to have a definite orientation: the high-latitude "lead" arms of the switchbacks are preferentially sinistral (dextral) in the north (south), while the lower latitude "return" arms are, in agreement with observations, preferentially dextral (sinistral). The predicted orientation of fields at the polar crown, however, appear to be in conflict with observations. Further observational studies are needed to determine whether the model can explain the observed hemispheric pattern. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ St Andrews, Dept Math & Computat Sci, St Andrews KY16 9SS, Fife, Scotland. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM vanballe@cfa.harvard.edu; eric@dcs.st-and.ac.uk OI van Ballegooijen, Adriaan/0000-0002-5622-3540 NR 52 TC 141 Z9 141 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 1998 VL 501 IS 2 BP 866 EP 881 DI 10.1086/305823 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101DB UT WOS:000074853400042 ER PT J AU Mazeh, T Goldberg, D Latham, DW AF Mazeh, T Goldberg, D Latham, DW TI The mass distribution of extrasolar planet candidates and spectroscopic binary low-mass companions SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : spectroscopic; planetary systems ID SOLAR NEIGHBORHOOD; STAR AB Spectroscopic orbits have been reported for nine unseen companions orbiting solar-type stars with minimum possible masses in the range 0.5-10 Jupiter masses. We compare the mass distribution of these nine planet candidates with the distribution of low-mass secondaries in spectroscopic binaries. Although we still have only a very small number of systems, the two distributions suggest two distinctive populations. The transition region between the two populations might be at the range of 10-30 Jupiter masses. C1 Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mazeh, T (reprint author), Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. EM mazeh@wise.tau.ac.il; dorit@wise.tau.ac.il; dlatham@cfa.harvard.edu NR 35 TC 22 Z9 22 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1998 VL 501 IS 2 BP L199 EP L203 DI 10.1086/311464 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101DG UT WOS:000074853900010 ER PT J AU Hoelzel, AR Potter, CW Best, PB AF Hoelzel, AR Potter, CW Best, PB TI Genetic differentiation between parapatric 'nearshore' and 'offshore' populations of the bottlenose dolphin SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE population genetics; marine mammals; resource specialization ID DNA AB The existence of nearshore and offshore populations of the bottlenose dolphin has been documented throughout its range. In several cases the two regional forms have been shown to be morphologically distinct, although there is considerable overlap for most characters. The populations off the eastern coast of North America have been the subject of a long-term programme of research on their distribution and movements. In this study, we compare mitochondrial and nuclear genetic markers between dolphins classified as either nearshore or offshore type. These putative populations were found to be distinct at both nuclear and mitochondrial genetic markers. Further, the level of variation among the nearshore dolphins was reduced compared with the offshore population. A broader geographical comparison suggests a shared lineage between offshore dolphins from the western North Atlantic and both offshore and nearshore dolphins from the eastern Atlantic. These results are consistent with local differentiation based on habitat or resource specialization in the western North Atlantic, and suggest differences in the character of the nearshore/offshore distinction in different parts of the world. C1 Univ Durham, Dept Biol Sci, Durham DH1 3LE, England. Smithsonian Inst, Museum Nat Hist, Washington, DC 20560 USA. Univ Pretoria, Mammal Res Inst, ZA-0002 Pretoria, South Africa. NCI, Lab Genom Divers, Frederick, MD 21701 USA. RP Hoelzel, AR (reprint author), Univ Durham, Dept Biol Sci, South Rd, Durham DH1 3LE, England. NR 29 TC 105 Z9 112 U1 5 U2 17 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 JUL 7 PY 1998 VL 265 IS 1402 BP 1177 EP 1183 PG 7 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA 102RR UT WOS:000074938500006 PM 9699311 ER PT J AU Aldrich, PR Hamrick, JL AF Aldrich, PR Hamrick, JL TI Reproductive dominance of pasture trees in a fragmented tropical forest mosaic SO SCIENCE LA English DT Article ID RAIN-FOREST; PATTERN; LIGHT AB Tropical forest fragmentation threatens biodiversity, yet basic information on population responses for major groups such as plants is lacking. Hypervariable genetic markers were used to reconstruct a population-level pedigree in fragmented tropical forest for the tree Symphonia globulifera. Though seedlings occurred only in remnant forest, the pedigree showed that most seedlings had been produced by sequentially fewer adults in pasture, creating a genetic bottleneck. The pedigree also implicated shifts in the foraging of animals that disperse pollen and seed in a secondary constriction of the bottleneck. These results suggest that tropical conservation strategies should anticipate complex, cryptic responses to fragmentation. C1 Univ Georgia, Dept Bot, Athens, GA 30602 USA. Univ Georgia, Dept Genet, Athens, GA 30602 USA. RP Aldrich, PR (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, MRC-166, Washington, DC 20560 USA. EM aldrich.preston@nmnh.si.edu NR 21 TC 199 Z9 216 U1 2 U2 17 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 JUL 3 PY 1998 VL 281 IS 5373 BP 103 EP 105 DI 10.1126/science.281.5373.103 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZZ009 UT WOS:000074685800047 ER PT J AU Rodman, JE Soltis, PS Soltis, DE Sytsma, KJ Karol, KG AF Rodman, JE Soltis, PS Soltis, DE Sytsma, KJ Karol, KG TI Parallel evolution of glucosinolate biosynthesis inferred from congruent nuclear and plastid gene phylogenies SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE Capparales sl; DNA sequencing; glucosinolates; phylogeny; rDNA (18S) ID SEQUENCE DATA; NUCLEOTIDE-SEQUENCES; TAXONOMIC ANALYSIS; AKANIA AKANIACEAE; SPECIES TREES; LARGE SUBUNIT; RBCL; MYROSINASE; PLANTS; CLASSIFICATION AB zThe phytochemical system of mustard-oil glucosides (glucosinolates) accompanied by the hydrolytic enzyme myrosinase (beta-thioglucosidase), the latter usually compartmented in special myrosin cells, characterizes plants in 16 families of angiosperms. Traditional classifications place these taxa in many separate orders and thus imply multiple convergences in the origin of this chemical defense system. DNA sequencing of the chloroplast rbcL gene for representatives of all 16 families and several putative relatives, with phylogenetic analyses by parsimony and maximum likelihood methods, demonstrated instead a single major clade of mustard-oil plants and one phylogenetic outlier. In a further independent test, DNA sequencing of the nuclear 18S ribosomal RNA gene for all these exemplars has yielded the same result, a major mustard-oil clade of 15 families (Akaniaceae, Bataceae, Brassicaceae, Bretschneideraceae, Capparaceae, Caricaceae, Gyrostemonaceae, Koeberliniaceae, Limnanthaceae, Moringaceae, Pentadiplandraceae, Resedaceae, Salvadoraceae, Tovariaceae, and Tropaeolaceae) and one outlier, the genus Drypetes, traditionally placed in Euphorbiaceae. Concatenating the two gene sequences (for a total of 3254 nucleotides) in a data set for 33 taxa, we obtain robust support for this finding of parallel origins of glucosinolate biosynthesis. From likely cyanogenic ancestors, the "mustard oil bomb" was invented twice. C1 Natl Sci Fdn, Div Environm Biol, Arlington, VA 22230 USA. Washington State Univ, Dept Bot, Pullman, WA 99164 USA. Univ Wisconsin, Dept Bot, Madison, WI 53706 USA. Smithsonian Inst, Lab Mol Systemat, Washington, DC 20560 USA. RP Rodman, JE (reprint author), Natl Sci Fdn, Div Environm Biol, Arlington, VA 22230 USA. EM jrodman@nsf.gov RI Soltis, Pamela/L-5184-2015 NR 68 TC 128 Z9 136 U1 0 U2 15 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 JUL PY 1998 VL 85 IS 7 BP 997 EP 1006 DI 10.2307/2446366 PG 10 WC Plant Sciences SC Plant Sciences GA 104DQ UT WOS:000074998000012 PM 21684983 ER PT J AU da Costa, LN Willmer, CNA Pellegrini, PS Chaves, OL Rite, C Maia, MAG Geller, MJ Latham, DW Kurtz, MJ Huchra, JP Ramella, M Fairall, AP Smith, C Lipari, S AF da Costa, LN Willmer, CNA Pellegrini, PS Chaves, OL Rite, C Maia, MAG Geller, MJ Latham, DW Kurtz, MJ Huchra, JP Ramella, M Fairall, AP Smith, C Lipari, S TI The southern sky redshift survey SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : distances and redshifts; galaxies : photometry ID LUMINOSITY FUNCTION; GALAXY REDSHIFTS; CCD CALIBRATION; MAGNITUDE SCALE; CFA; UNIVERSE; CATALOG; SAMPLE; SLICE AB We report redshifts, magnitudes, and morphological classifications for 5369 galaxies with m(B) less than or equal to 15.5 and for 57 galaxies fainter than this limit, in two regions covering a total of 1.70 sr in the southern celestial hemisphere. The galaxy catalog is drawn primarily from the list of nonstellar objects identified in the Hubble Space Telescope Guide Star Catalog (GSC). The galaxies have positions accurate to similar to 1 " and magnitudes with an rms scatter of similar to 0.3 mag. We compute magnitudes (m(SSRS2)) from the relation between instrumental GSC magnitudes and the photometry by Lauberts & Valentijn. From a comparison with CCD photometry, we find that our system is homogeneous across the sky and corresponds to magnitudes measured at the isophotal level similar to 26 mag arcsec(-2). The precision of the radial velocities is similar to 40 km s(-1), and the redshift survey is more than 99% complete to the m(SSRS2) = 15.5 mag limit. This sample is in the direction opposite that of the CfA2; in combination the two surveys provide an important database for studies of the properties of galaxies and their large-scale distribution in the nearby universe. C1 European So Observ, D-85748 Munchen, Germany. Observ Nacl, Dept Astron, BR-20921030 Sao Cristovao, RJ, Brazil. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron Trieste, I-34131 Trieste, Italy. Univ Cape Town, Dept Astron, ZA-7735 Rondebosch, South Africa. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Observ Astron Cordoba, RA-5000 Cordoba, Argentina. RP da Costa, LN (reprint author), Observ Nacl, Dept Astron, Rua Gen Jose Cristino 77, BR-20921030 Sao Cristovao, RJ, Brazil. RI KURTZ, Michael /B-3890-2009; OI Kurtz, Michael/0000-0002-6949-0090 NR 39 TC 126 Z9 126 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1998 VL 116 IS 1 BP 1 EP 7 DI 10.1086/300410 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500001 ER PT J AU Maoz, D Koratkar, A Shields, JC Ho, LC Filippenko, AV Sternberg, A AF Maoz, D Koratkar, A Shields, JC Ho, LC Filippenko, AV Sternberg, A TI The ultraviolet spectra of LINERs: A comparative study SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : nuclei; galaxies : star clusters; ultraviolet emission ID GALACTIC NUCLEI; EXTINCTION LAW; EMISSION-LINES; O-STARS; GALAXIES; STARBURST; DUST; SPECTROSCOPY; DIAGNOSTICS; SEARCH AB Imaging studies have shown that similar to 25% of LINER galaxies display a compact nuclear UV source. As part of a program to study the nature of LINERs and their connection to the active galaxy phenomenon, we compare the Hubble Space Telescope UV (1150-3200 Angstrom) spectra of seven such UV-bright LINERs. Data for three of the galaxies (NGC 404, 4569, and 5055) are presented for the first time, while data for four others (M81, NGC 4594, NGC 4579, and NGC 6500) have been recently published. The spectra of NGC 404, 4569, and 5055 show clear absorption-line signatures of massive stars, indicating a stellar origin for the UV continuum. Similar features are probably present in NGC 6500. The same stellar signatures may be present but undetectable in NGC 4594, because of the low signal-to-noise ratio of the spectrum, and in M81 and NGC 4579, because of superposed strong, broad emission lines. The compact central UV continuum source that is observed in these galaxies is a nuclear star cluster rather than a low-luminosity active galactic nucleus (AGN), at least in some cases. Except for the two LINERs with broad emission lines (M81 and NGC 4579), the LINERs have weak or no detectable UV emission lines. The UV emission-line spectrum strength shows no relation to the UV continuum strength. Furthermore, at least four of the LINERs suffer from an ionizing photon deficit in the sense that the ionizing photon flux inferred from the observed far-UV continuum is insufficient to drive the optical H I recombination lines. Examination of the nuclear X-ray flux of each galaxy shows a high X-ray-to-UV ratio in the four "UV photon-starved" LINERs. In these four objects, a separate component, emitting predominantly in the extreme-UV, is the likely ionizing agent and is perhaps unrelated to the observed nuclear UV emission. Future observations can determine whether the UV continuum in LINERs is always dominated by a starburst or, alternatively, that there are two types of UV-bright LINERs: starburst dominated and AGN dominated. C1 Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, IL-69978 Tel Aviv, Israel. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Ohio Univ, Dept Phys & Astron, Athens, OH 45701 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Maoz, D (reprint author), Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. NR 67 TC 136 Z9 136 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1998 VL 116 IS 1 BP 55 EP 67 DI 10.1086/300403 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500009 ER PT J AU Tyson, JA Fischer, P Guhathakurta, P McIlroy, P Wenk, R Huchra, J Macri, L Neuschaefer, L Sarajedini, V Glazebrook, K Ratnatunga, K Griffiths, R AF Tyson, JA Fischer, P Guhathakurta, P McIlroy, P Wenk, R Huchra, J Macri, L Neuschaefer, L Sarajedini, V Glazebrook, K Ratnatunga, K Griffiths, R TI Deep optical imaging of the bright Seyfert galaxy NGC 5548: A long, very low surface brightness tail SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : individual (NGC 5548); galaxies : Seyfert ID PLANETARY CAMERA OBSERVATIONS; YOUNG GLOBULAR-CLUSTERS; MERGER REMNANT NGC-7252; ACTIVE GALACTIC NUCLEI; H-I OBSERVATIONS; INTERACTING GALAXIES; STAR-CLUSTERS; ELLIPTICAL GALAXIES; TIDAL TAILS; HUBBLE AB Deep Hubble Space Telescope Wide Field Camera (WFC-1) imaging of a region 3.'7 east of the V = 13 mag Seyfert galaxy NGC 5548 in the F555W and F785LP bands, and deep ground-based V and I imaging, show a new extended, blue, low surface brightness structure, apparently a remnant of a tidal interaction associated with NGC 5548. If this straight, low surface brightness (V similar to 27-28 mag arcsec(-2)) tidal tail is associated with NGC 5548, it extends at least 80 kpc from it and has an absolute magnitude of M-V approximate to -16.4 (H-0 = 65 km s(-1) Mpc(-1)). Previous imaging surveys of Seyfert galaxies would have missed such low surface brightness tails. Morphologically similar to some brighter tails seen in other interacting systems and in simulations of merging galaxies, this faint tail is a useful diagnostic of an earlier interaction and of the progenitors' halo-to-disk mass ratios. Luminous ripples and a brighter tail wrapped around the galaxy are seen in the inner 1-10 kpc region. Unresolved blue objects in the long tail have the colors and absolute magnitudes of young globular clusters. Taken together, the two tails and other features suggest that two spirals merged less than approximate to 1 Gyr ago. The inner luminosity profile of NGC 5548 is a good fit to a de Vaucouleurs profile with r(eff) = 5.8 kpc. Recent simulations of merged galaxies with high-mass halos fail to form lasting tidal tails, suggesting that the NGC 5548 progenitor spirals had modest halo masses. C1 AT&T Bell Labs, Lucent TEchnol, Murray Hill, NJ 07974 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Calif Santa Cruz, UCO Lick Observ, Santa Cruz, CA 95064 USA. Rutgers State Univ, Dept Comp Sci, Piscataway, NJ 08855 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. BCSi Inc, Colorado Springs, CO 80908 USA. Univ Arizona, Steward Observ, Tucson, AZ 85719 USA. Anglo Australian Observ, Epping, NSW 2121, Australia. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. RP Tyson, JA (reprint author), AT&T Bell Labs, Lucent TEchnol, 700 Mt Ave, Murray Hill, NJ 07974 USA. RI Glazebrook, Karl/N-3488-2015; OI Glazebrook, Karl/0000-0002-3254-9044; Macri, Lucas/0000-0002-1775-4859 NR 54 TC 19 Z9 19 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1998 VL 116 IS 1 BP 102 EP 110 DI 10.1086/300395 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500012 ER PT J AU Bresolin, F Kennicutt, RC Ferrarese, L Gibson, BK Graham, JA Macri, LM Phelps, RL Rawson, DM Sakai, S Silbermann, NA Stetson, PB Turner, AM AF Bresolin, F Kennicutt, RC Ferrarese, L Gibson, BK Graham, JA Macri, LM Phelps, RL Rawson, DM Sakai, S Silbermann, NA Stetson, PB Turner, AM TI A Hubble Space Telescope study of extragalactic OB associations SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : stellar content ID MASSIVE STARS; ANDROMEDA GALAXY; NEARBY GALAXIES; LUMINOSITY; PHOTOMETRY; COMPLEXES; CLUSTERS; SAMPLE; IMAGES; HST AB We present a study of OB associations, identified by objective means, in seven spiral galaxies observed with the Hubble Space Telescope as part of the Key Project on the distance scale. The properties of the associations, including their size distribution and average diameter, and the luminosity function of their brightest stars, do not vary significantly among galaxies, even for changes in Hubble type. These findings support previous suggestions about the existence of similarly sized elementary cells of star formation in galaxies, and the conclusion, obtained by others with more extensive data, that the upper stellar mass function does not vary significantly. The data suggest that the average number of stars in associations changes with morphological type, confirming previous studies of the integrated magnitudes of OB associations in H II regions. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. European So Observ, D-85748 Munich, Germany. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Inst Adv Studies, Weston, ACT 2611, Australia. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. RP Bresolin, F (reprint author), Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA. RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 37 TC 38 Z9 38 U1 0 U2 0 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 JUL PY 1998 VL 116 IS 1 BP 119 EP 130 DI 10.1086/300424 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500014 ER PT J AU Adams, NR Walter, FM Wolk, SJ AF Adams, NR Walter, FM Wolk, SJ TI Rotation periods of low-mass stars of the Upper Scorpius OB association SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : evolution; stars : pre-main-sequence; stars : rotation; stars : spots ID T-TAURI STARS; MAIN-SEQUENCE STARS; TRAPEZIUM CLUSTER; ORION NEBULA; YOUNG STARS; VARIABILITY; MODEL; DISKS; CONVECTION; VELOCITIES AB We present results from a rotation period study of 21 pre-main-sequence stars in the Upper Scorpius OB association. Eleven stars have periodic variability consistent with stellar rotation. We discuss the period-searching methods and false-alarm probability calculations. Since the pre-main-sequence population of the Upper Sco region has not been examined as thoroughly as those of other star-forming regions, we compare our results with the Taurus-Auriga and Trapezium star-forming regions. We note a different distribution of P-rot in Upper Sco. We use the P-rot distribution to estimate the stellar spin-up times in this association. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. SUNY Stony Brook, Astron Program, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. RP Adams, NR (reprint author), SUNY Stony Brook, Astron Program, Stony Brook, NY 11794 USA. OI Wolk, Scott/0000-0002-0826-9261 NR 35 TC 8 Z9 8 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1998 VL 116 IS 1 BP 237 EP 244 DI 10.1086/300393 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500021 ER PT J AU Soderblom, DR King, JR Henry, TJ AF Soderblom, DR King, JR Henry, TJ TI High-resolution spectroscopy of some very active southern stars SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : spectroscopic; stars : abundances; stars : chromospheres; stars : kinematics; stars : late-type; stars : rotation ID EINSTEIN-SLEW SURVEY; SOLAR-TYPE STARS; RS CVN BINARIES; CA-II H; CHROMOSPHERIC EMISSION; STROMGREN PHOTOMETRY; LOCAL ASSOCIATION; UVBY PHOTOMETRY; SOURCE CATALOG; MAIN-SEQUENCE AB We have obtained high-resolution echelle spectra of 18 solar-type stars that an earlier survey showed to have very high levels of Ca II H and K emission. Most of these stars belong to close binary systems, but five remain as probable single stars or well-separated binaries that are younger than the Pleiades on the basis of their lithium abundances and Ha emission. Three of these probable single stars also lie more than 1 mag above the main sequence in a color-magnitude diagram, and appear to have ages of 10 to 15 Myr. Two of them, HD 202917 and HD 222259, also appear to have a kinematic association with the pre-main-sequence multiple system HD 98800. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Soderblom, DR (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 46 TC 37 Z9 37 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1998 VL 116 IS 1 BP 396 EP 413 DI 10.1086/300423 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500034 ER PT J AU Muzerolle, J Hartmann, L Calvet, N AF Muzerolle, J Hartmann, L Calvet, N TI Emission-line diagnostics of T Tauri magnetospheric accretion. I. Line profile observations SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : pre-main-sequence; techniques : spectroscopic ID YOUNG STARS; MASS-LOSS; FORBIDDEN-LINE; DISK ACCRETION; WINDS; MODELS; SPECTRA; FLOWS AB We present high-resolution spectra of classical T Tauri stars in Taurus in the range 5800-9000 Angstrom to critically examine the current theories of magnetospheric accretion. In this paper, we focus on the emission lines of hydrogen (the higher Paschen series and H alpha), He I lambda 5876, O I lambda 7773 and lambda 8446, the Na D lines, and the Ca II infrared triplet. We argue that the magnetospheric infall zone is the likely source of emission for the hydrogen, oxygen, and sodium lines for most of the stars in our sample. As has been previously shown, the calcium and helium lines have a narrow and a broad component; focusing on the broad components, we find that they are likely formed in the magnetosphere for at least several of the stars in the sample. Preliminary calculations indicate that the magnetospheric models developed to explain the Balmer lines predict significant Ca II, Paschen, and O I emission, roughly comparable to what is observed. However, in some of the stars, especially at high veilings, the case for line formation in the accretion flow is not clear. Finally, our results suggest that the Ca II IR triplet lines are good indicators of the accretion rate for all but the most weakly accreting T Tauri stars. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Massachusetts, Five Coll Astron Dept, Amherst, MA 01003 USA. Ctr Invest Astron, Merida, Venezuela. RP Muzerolle, J (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,Mail Stop 42, Cambridge, MA 02138 USA. NR 44 TC 171 Z9 171 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1998 VL 116 IS 1 BP 455 EP 468 DI 10.1086/300428 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500041 ER PT J AU Jurgens, RF Rojas, F Slade, MA Standish, EM Chandler, JF AF Jurgens, RF Rojas, F Slade, MA Standish, EM Chandler, JF TI Mercury radar ranging data from 1987 to 1997 SO ASTRONOMICAL JOURNAL LA English DT Article DE ephemerides; planets and satellites : individual (Mercury) AB This is a brief report on radar ranging data to the subradar point on Mercury. This report makes available 10 years of such data, from 1987 to 1997. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Jurgens, RF (reprint author), CALTECH, Jet Prop Lab, Mail Stop 238-420, Pasadena, CA 91109 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 1998 VL 116 IS 1 BP 486 EP 488 DI 10.1086/300439 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 104KB UT WOS:000075012500044 ER PT J AU Durret, F Forman, W Gerbal, D Jones, C Vikhlinin, A AF Durret, F Forman, W Gerbal, D Jones, C Vikhlinin, A TI The rich cluster of galaxies ABCG 85 - III. Analyzing the ABCG 85/87/89 complex SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : clusters : general; clusters : individual : ABCG 85; X-rays : galaxies ID RAY AB We present a combined X-ray and optical analysis of the ABCG 85/87/89 complex of clusters of galaxies, based on the ROSAT PSPC image, optical photometric catalogues (Slezak et al. 1998), and an optical redshift catalogue (Durret et al. 1998). From this combined data set, we find striking alignments at all scales at PA similar or equal to 160 degrees. At small scales, the cD galaxy in ABCG 85 and the brightest galaxies in the cluster are aligned along this PA. At a larger scale, X-ray emission defines a comparable PA south-southeast of ABCG 85 towards ABCG 87, with a patchy X-ray structure very different from the regular shape of the optical galaxy distribution in ABCG 87. The galaxy velocities in the ABCG 87 region show the existence of subgroups, which all have an X-ray counterpart, and seem to be falling onto ABCG 85 along a filament almost perpendicular to the plane of the sky. To the west of ABCG 85, ABCG 89 appears as a significant galaxy density enhancement, but is barely detected at X-ray wavelengths. The galaxy velocities reveal that in fact this is not a cluster but two groups with very different velocities superimposed along the line of sight. These two groups appear to be located in intersecting sheets on opposite sides of a large bubble. These data and their interpretation reinforce the cosmological scenario in which matter, including galaxies, groups and gas, falls onto the cluster along a filament. C1 Univ Pierre & Marie Curie, Inst Astrophys Paris, CNRS, F-75014 Paris, France. Univ Paris 07, Observ Paris, DAEC, CNRS,UA 173, F-92195 Meudon, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Durret, F (reprint author), Univ Pierre & Marie Curie, Inst Astrophys Paris, CNRS, 98 Bis Bd Arago, F-75014 Paris, France. NR 29 TC 38 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 JUL 1 PY 1998 VL 335 IS 1 BP 41 EP 48 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ318 UT WOS:000074717400012 ER PT J AU Bouchy, F Lestrade, JF Ransom, RR Bartel, N Ratner, MI Shapiro, II AF Bouchy, F Lestrade, JF Ransom, RR Bartel, N Ratner, MI Shapiro, II TI Possible superluminal motion between two stationary components in the high-redshift quasar 1338+381 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : jets; cosmology : observations; galaxies : distances and redshifts; quasars : individual : 1338+381 ID RADIO; MAPS AB VLBI maps of the high-redshift quasar 1338+381 (z = 3.1) have been made at five epochs between September 1992 and May 1994. They reveal structure with two well defined components separated by 3.6 milliarcseconds and suggest at one epoch a third weaker component in between. We have significant evidence that the two main components are stationary over the 1.7 year period of observations and might result from a bent jet structure, as in 4C 39.25. We propose a scenario in which the weaker third component moves between the two stationnary components at the high apparent velocity of 27 +/- 17 h(-1) c. We discuss briefly the location of this new compact F double source in the mu - z diagram. C1 Observ Meudon, F-92195 Meudon, France. York Univ, Dept Phys & Astron, N York, ON M3J 1P3, Canada. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Bouchy, F (reprint author), Observ Meudon, F-92195 Meudon, France. NR 25 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 JUL 1 PY 1998 VL 335 IS 1 BP 145 EP 151 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ318 UT WOS:000074717400021 ER PT J AU Silverman, JD Harris, DE Junor, W AF Silverman, JD Harris, DE Junor, W TI Multiwavelength observations of 26W20, a radio galaxy which displays BL Lacertae characteristics SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE radio continuum : galaxies; X-rays : galaxies; BL Lacertae objects : individual : 26W20; galaxies : jets ID CLUSTERS AB 26W20, a radio galaxy located at a projected distance of 2.2 Mpc from the center of Abell 754 (z = 0.054) exhibits core emission properties similar to those of a BL Lac object. New radio observations and VLA archival data show parsec scale features in the core (L-r similar to 10(41) ergs s(-1)) with a flat spectrum. From observations with ROSAT, we demonstrate that the X-ray core emission (L-x = 3 x 10(43) ergs s(-1)) is nonthermal and variable. An 18% increase in the X-ray luminosity was observed in two observations separated by five days. The optical morphology is that of a large, normal elliptical galaxy (m(v) = 15.6) and the optical spectrum lacks strong emission lines. If the innermost segment of the radio jet is close to our line of sight, Doppler boosting could explain both the observed X-ray intensity and the absence of emitting line regions. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. RP Harris, DE (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 12 TC 7 Z9 7 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 JUL PY 1998 VL 335 IS 2 BP 443 EP 448 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101MX UT WOS:000074873700011 ER PT J AU Henkel, C Wang, YP Falcke, H Wilson, AS Braatz, JA AF Henkel, C Wang, YP Falcke, H Wilson, AS Braatz, JA TI H2O megamaser emission from FRI radio galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE masers; ISM : molecules; galaxies : elliptical and lenticular; galaxies : ISM; galaxies : active; radio lines : galaxies ID H-I ABSORPTION; ACTIVE GALAXIES; BLACK-HOLE; NGC-4258; CALIBRATORS; NUCLEUS; MASER; DISK AB A systematic search for 22 GHz H2O megamaser emission is reported for 50 nearby (z less than or similar to 0.15) FRI galaxies. No detection was obtained, implying that ultraluminous H2O masers (L-H2O > 10(3) L-.) must be rare in early-type galaxies with FR I radio morphology. Despite higher radio core luminosities the detection rate for our sample is lower than in similar surveys of late-type Seyfert galaxies. This puzzling difference between Seyferts and low-power radio galaxies could be explained in several ways: a) the maser emission is saturated and therefore independent of the radio core luminosity, b) the masers are unsaturated and originate in a thin circumnuclear gas disk, so the 'seed' radio continuum would come from the far jet which is relativistically dimmed or c) the amount, kinematics, or the distribution of the molecular gas in the nuclei of Seyferts and radio galaxies is different. Further studies of maser properties may provide clues to the differences between radio-loud and radio-quiet AGN. C1 Max Planck Inst Radioastron, D-53121 Bonn, Germany. European So Observ, Santiago 19, Chile. Acad Sinica, Purple Mt Observ, Nanjing 210008, Peoples R China. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Henkel, C (reprint author), Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany. EM p220hen@mpifr-bonn.mpg.de RI Falcke, Heino/H-5262-2012 OI Falcke, Heino/0000-0002-2526-6724 NR 25 TC 30 Z9 32 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 JUL PY 1998 VL 335 IS 2 BP 463 EP 466 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101MX UT WOS:000074873700013 ER PT J AU Hughes, JP Birkinshaw, M AF Hughes, JP Birkinshaw, M TI A measurement of the Hubble constant from the X-ray properties and the Sunyaev-Zeldovich effect of CL 0016+16 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; distance scale; galaxies : clusters : individual (CL0016+16); intergalactic medium ID COMA CLUSTER; HOT PLASMA; GALAXIES; DISTANCE; TEMPERATURE; SUPERNOVAE; ABELL-665; IRON AB A value of the Hubble constant has been determined from a comparison of the X-ray properties and Sunyaev-Zeldovich effect of the distant rich cluster of galaxies CL 0016 + 16. The cluster, as imaged by the ROSAT PSPC, is significantly elliptical, and we present the techniques we have developed to include this in our analysis. Assuming a smooth, isothermal gas distribution, we obtain a value H-0 = 47(-15)(+23) km s(-1) Mpc(-1), where the errors include systematic and random uncertainties but are purely observational. Systematic errors in deprojecting the elliptical surface brightness distribution due to prolate and oblate geometries as well as arbitrary inclination angles, introduce an additional fractional error of +/-17% in H-0. At the redshift of CL 0016 + 16 (z = 0.5455) the effect of the cosmological parameters on the derived H-0 value is of order 10%-20%; we quote results for q(0) = 0.1. Combining this result with X-ray/SZ effect H-0 determinations from seven other clusters and taking account of systematic uncertainties in our models for the cluster atmosphere, we find an ensemble value of H-0 = 42-61 km s(-1) Mpc(-1) with an additional random error of +/-16%. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Hughes, JP (reprint author), Rutgers State Univ, Dept Phys & Astron, 136 Frelinghuysen Rd, Piscataway, NJ 08854 USA. NR 58 TC 95 Z9 95 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP 1 EP 14 DI 10.1086/305788 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ946 UT WOS:000074785300001 ER PT J AU Hughes, SMG Han, MS Hoessel, J Freedman, WL Kennicutt, RC Mould, JR Saha, A Stetson, PB Madore, BF Silberman, NA Harding, P Ferrarese, L Ford, H Gibson, BK Graham, JA Hill, R Huchra, J Illingworth, GD Phelps, R Sakai, S AF Hughes, SMG Han, MS Hoessel, J Freedman, WL Kennicutt, RC Mould, JR Saha, A Stetson, PB Madore, BF Silberman, NA Harding, P Ferrarese, L Ford, H Gibson, BK Graham, JA Hill, R Huchra, J Illingworth, GD Phelps, R Sakai, S TI The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid distance to NGC 7331 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; galaxies : distances and redshifts; galaxies : individual (NGC 7331); galaxies : photometry ID H-II REGIONS; PERIOD-LUMINOSITY RELATION; VELOCITY-WIDTH RELATION; SPIRAL GALAXIES; METALLICITY DEPENDENCE; MAGELLANIC CLOUD; NEARBY GALAXIES; CCD PHOTOMETRY; DISCOVERY; CALIBRATION AB The distance to NGC 7331 has been derived from Cepheid variables observed with the Hubble Space Telescope (HST) WFPC2, as part of the Extragalactic Distance Scale Key Project. Multiepoch exposures in F555W (similar to V) and F814W (similar to I), with photometry derived independently from DoPHOT and DAOPHOT/ALLFRAME programs, were used to detect a total of 13 reliable Cepheids, with periods between 11 and 42 days. The relative distance moduli between NGC 7331 and the LMC, derived from the V and I magnitudes, imply an extinction to NGC 7331 of A(v) = 0.47 +/- 0.15 mag and an extinction-corrected distance modulus to NGC 7331 of 30.89 +/- 0.14 (random), equivalent to a distance of 15.1(-0.9)(+1.0) Mpc. There are additional systematic uncertainties in the distance modulus of +/-0.12 mag resulting from the calibration of the Cepheid period-luminosity relation and a systematic offset of +0.05 +/- 0.04 mag if the metallicity correction inferred from the M101 results of Kennicutt et al. are applied. C1 Royal Greenwich Observ, Cambridge CB3 0EZ, England. Univ Wisconsin, Madison, WI 53706 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Canberra, ACT, Australia. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. CALTECH, Ctr Infrared Proc & Anal, NASA, Extragalact Database, Pasadena, CA 91125 USA. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Hughes, SMG (reprint author), Royal Greenwich Observ, Madingley Rd, Cambridge CB3 0EZ, England. EM hughes@ast.cam.ac.uk; mhan@malachi.gsfc.nasa.gov; hoessel@uwfpc.astro.wisc.edu; wendy@ociw.edu; robk@as.arizona.edu; jrm@merlin.anu.edu.au; saha@noao.edu; peter.stetson@hia.nrc.ca; barry@ipac.caltech.edu; nancys@ipac.caltech.edu; harding@as.arizona.edu; lff@astro.caltech.edu; ford@stsci.edu; gibson@mso.anu.edu.au; graham@jag.ciw.edu; hill@esa.nascom.nasa.gov; huchra@cfa.harvard.edu; gdi@ucolick.org; phelps@ociw.edu; shoko@ipac.caltech.edu RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 73 TC 53 Z9 53 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP 32 EP 53 DI 10.1086/305808 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ946 UT WOS:000074785300004 ER PT J AU Proga, D Kenyon, SJ Raymond, JC AF Proga, D Kenyon, SJ Raymond, JC TI Illumination in symbiotic binary stars: Non-LTE photoionization models. II. Wind case SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : symbiotic; radiative transfer; stars : emission-line, Be; stars : late-type ID EMISSION-LINE SPECTRUM; NOVA AG-PEGASI; EG-ANDROMEDAE; ACCRETION DISKS; RADIO SURVEY; RED GIANTS; VV CEPHEI; HE-I; EVOLUTION; ABUNDANCES AB We describe a non-LTE photoionization code to calculate the wind structure and emergent spectrum of a red giant wind illuminated by the hot component of a symbiotic binary system. We consider spherically symmetric winds with several different velocity and temperature laws and derive predicted line fluxes as a function of the red giant mass-loss rate, (M)over dot. Our models generally match observations of the symbiotic stars EG And and AG Peg for (M)over dot approximate to 10(-8) to 10(-7) M. yr(-1). The optically thick cross section of the red giant wind as viewed from the hot component is a crucial parameter in these models. Winds with cross sections of 2-3 red giant radii reproduce the observed fluxes because the wind density is then high: similar to 10(9) cm(-3). Our models favor winds with acceleration regions that either lie far from the red giant photosphere or extend for 2-3 red giant radii. C1 Univ London Imperial Coll Sci Technol & Med, London SW7 2BZ, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Proga, D (reprint author), Univ London Imperial Coll Sci Technol & Med, Prince Consort Rd, London SW7 2BZ, England. OI Kenyon, Scott/0000-0003-0214-609X NR 61 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP 339 EP 356 DI 10.1086/305792 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ946 UT WOS:000074785300028 ER PT J AU Kohl, JL Noci, G Antonucci, E Tondello, G Huber, MCE Cranmer, SR Strachan, L Panasyuk, AV Gardner, LD Romoli, M Fineschi, S Dobrzycka, D Raymond, JC Nicolosi, P Siegmund, OHW Spadaro, D Benna, C Ciaravella, A Giordano, S Habbal, SR Karovska, M Li, X Martin, R Michels, JG Modigliani, A Naletto, G O'Neal, RH Pernechele, C Poletto, G Smith, PL Suleiman, RM AF Kohl, JL Noci, G Antonucci, E Tondello, G Huber, MCE Cranmer, SR Strachan, L Panasyuk, AV Gardner, LD Romoli, M Fineschi, S Dobrzycka, D Raymond, JC Nicolosi, P Siegmund, OHW Spadaro, D Benna, C Ciaravella, A Giordano, S Habbal, SR Karovska, M Li, X Martin, R Michels, JG Modigliani, A Naletto, G O'Neal, RH Pernechele, C Poletto, G Smith, PL Suleiman, RM TI UVCS/SOHO empirical determinations of anisotropic velocity distributions in the solar corona SO ASTROPHYSICAL JOURNAL LA English DT Article DE line : profiles; solar wind; Sun : corona; Sun : UV radiation ID STRAY-LIGHT; WIND; ACCELERATION; IONS; DYNAMICS; SPEED; HOLE AB We present a self-consistent empirical model for several plasma parameters of a polar coronal hole near solar minimum, derived from observations with the Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer. The model describes the radial distribution of density for electrons, H-0, and O5+ and the outflow velocity and unresolved most probable velocities for H-0 and O5+ during the period between 1996 November and 1997 April. In this Letter, we compare observations of H I Ly alpha and O VI lambda lambda 1032, 1037 emission lines with spatial models of the plasma parameters, and we iterate for optimal consistency between measured and synthesized observable quantities. The unexpectedly large line widths of H-0 atoms and O5+ ions at most radii are the result of anisotropic velocity distributions, which are not consistent with purely thermal motions or the expected motions from a combination of thermal and transverse wave velocities. Above 2 R., the observed transverse, most probable speeds for O5+ are significantly larger than the corresponding motions for H-0, and the outflow velocities of O5+ are also significantly larger than the corresponding velocities of H-0. 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, I-50125 Florence, Italy. Osservatorio Astron Torino, I-10025 Pino Torinese, Italy. Univ Padua, I-35131 Padua, Italy. European Space Agcy, European Space Res & Technol Ctr, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Turin, I-10125 Turin, Italy. Osservatorio Astrofis Catania, I-95125 Catania, Italy. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. RP Kohl, JL (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Romoli, Marco/H-6859-2012; Naletto, Giampiero/S-6329-2016; OI Naletto, Giampiero/0000-0003-2007-3138; Ciaravella, Angela/0000-0002-3127-8078; Benna, Carlo/0000-0003-1688-2434; Spadaro, Daniele/0000-0003-3517-8688; Giordano, Silvio/0000-0002-3468-8566 NR 38 TC 257 Z9 259 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP L127 EP L131 DI 10.1086/311434 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ948 UT WOS:000074785500027 ER PT J AU Li, X Habbal, SR Kohl, JL Noci, G AF Li, X Habbal, SR Kohl, JL Noci, G TI The effect of temperature anisotropy on observations of Doppler dimming and pumping in the inner corona SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : corona; Sun : UV radiation ID SOLAR AB Recent observations of the spectral line profiles and intensity ratio of the O VI lambda lambda 1032 and 1037.6 doublet by the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO), made in coronal holes below 3.5 R-S, provide evidence for Doppler dimming of the O VI lambda 1037.6 line and pumping by the chromospheric C II lambda 1037.0182 line. Evidence for a significant kinetic temperature anisotropy of O5+ ions was also derived from these observations. We show in this Letter how the component of the kinetic temperature in the direction perpendicular to the magnetic field, for both isotropic and anisotropic temperature distributions, affects both the amount of Doppler dimming and pumping. Taking this component into account, we further show that the observation of the O VI doublet intensity ratio less than unity can be accounted for only if pumping by C II lambda 1036.3367 in addition to C II lambda 1037.0182 is in effect. The inclusion of the C II lambda 1036.3367 pumping implies that the speed of the O5+ ions can reach 400 km s(-1) around 3 R-S, which is significantly higher than the reported UVCS values for atomic hydrogen in polar coronal holes. These results imply that oxygen ions flow much faster than protons at that heliocentric distance. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Sci & Technol China, Dept Earth & Space Sci, Hefei 230026, Anhui, Peoples R China. Univ Firenze, I-2025 Firenze, Italy. RP Li, X (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 19 TC 149 Z9 151 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP L133 EP L137 DI 10.1086/311428 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ948 UT WOS:000074785500028 ER PT J AU O'Neal, D Saar, SH Neff, JE AF O'Neal, D Saar, SH Neff, JE TI Spectroscopic evidence for nonuniform starspot properties on II Pegasi SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : activity; stars : atmospheres; stars : late-type; stars : magnetic fields; techniques : spectroscopic ID RS CANUM-VENATICORUM; TEMPERATURE; SPOTS; AREA AB We present spectroscopic evidence for multiple spot temperatures on the RS CVn star II Pegasi (HD 224085). We model the strengths of the 7055 and 8860 Angstrom TiO absorption bands in the spectrum of II Peg using weighted sums of inactive comparison spectra: a K star to represent the nonspotted photosphere and an M star to represent the spots. The best fit yields independent measurements of the starspot filling factor (f(S)) and mean spot temperature ([T-S]) averaged over the visible hemisphere of the star. During three-fourths of a rotation of II Peg in late 1996, we measure a constant f(S) approximate to 55% +/- 5%. However, [T-S] varies from 3350 +/- 60 to 3550 +/- 70 K. We compute [T-S] for two simple models: (1) a star with two distinct spot temperatures, and (2) a star with different umbral/penumbral area ratios. The changing [T-S] correlates with emission strengths of H alpha and the Ca II infrared triplet in the sense that cooler [T-S] accompanies weaker emission. We explore possible implications of these results for the physical properties of the spots on II Peg and for stellar surface structure in general. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Coll Charleston, Dept Phys & Astron, Charleston, SC 29424 USA. RP O'Neal, D (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. EM doneal@casa.colorado.edu; saar@cfa.harvard.edu; neffj@cofc.edu NR 27 TC 23 Z9 23 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP L73 EP L76 DI 10.1086/311441 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ948 UT WOS:000074785500017 ER PT J AU Psaltis, D Mendez, M Wijnands, R Homan, J Jonker, PG van der Klis, M Lamb, FK Kuulkers, E van Paradijs, J Lewin, WHG AF Psaltis, D Mendez, M Wijnands, R Homan, J Jonker, PG van der Klis, M Lamb, FK Kuulkers, E van Paradijs, J Lewin, WHG TI The beat-frequency interpretation of kilohertz quasi-periodic oscillations in neutron star low-mass X-ray binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : neutron; X-rays : stars AB Pairs of quasi-periodic oscillations (QPOs) at kilohertz frequencies are a common phenomenon in several neutron-star low-mass X-ray binaries. The frequency separation of the QPO peaks in the pair appears to be constant in many sources and directly related to the neutron star spin frequency. However, in Sco X-l and possible in 4U 1608-52, the frequency separation between the QPO peaks decreases with increasing inferred mass accretion rate. We show that the currently available Rossi X-Ray Timing Explorer data an consistent with the hypothesis that the peak separations in all sources vary by amounts similar to the variation in Sco X-l. We discuss the implications for models of the kilohertz QPOs. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. 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. Univ Nacl La Plata, Fac Ciencias Astron & Geofis, RA-1090 La Plata, Argentina. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Illinois, Dept Phys & Astron, Urbana, IL 61801 USA. Univ Oxford, Nucl & Astrophys Lab, Oxford OX1 3RH, England. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. MIT, Dept Phys, Cambridge, MA 02139 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. RI Mendez, Mariano/C-8011-2012 OI Mendez, Mariano/0000-0003-2187-2708 NR 27 TC 63 Z9 64 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP L95 EP L99 DI 10.1086/311455 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ948 UT WOS:000074785500021 ER PT J AU Samuelson, FW Biller, SD Bond, IH Boyle, PJ Bradbury, SM Breslin, A Buckley, JH Burdett, AM Gordo, JB Carter-Lewis, DA Catanese, M Cawley, MF Fegan, DJ Finley, JP Gaidos, JA Hall, T Hillas, AM Krennrich, F Lamb, RC Lessard, RW McEnery, JE Masterson, C Quinn, J Rodgers, AJ Rose, HJ Sembroski, GH Srinivasan, R Vassiliev, VV Weekes, TC Zweerink, J AF Samuelson, FW Biller, SD Bond, IH Boyle, PJ Bradbury, SM Breslin, A Buckley, JH Burdett, AM Gordo, JB Carter-Lewis, DA Catanese, M Cawley, MF Fegan, DJ Finley, JP Gaidos, JA Hall, T Hillas, AM Krennrich, F Lamb, RC Lessard, RW McEnery, JE Masterson, C Quinn, J Rodgers, AJ Rose, HJ Sembroski, GH Srinivasan, R Vassiliev, VV Weekes, TC Zweerink, J TI The TeV spectrum of Markarian 501 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : individual (Markarian 501); gamma rays : observations ID INTERGALACTIC INFRARED RADIATION; ACTIVE GALAXY MARKARIAN-421; GAMMA-RAYS; PHOTONS; BLAZAR AB The energy spectrum of the active galactic nucleus Markarian 501 has been determined from 0.3 to 10 TeV with the Whipple Observatory Cerenkov Imaging Telescope, by using both small zenith angle and large zenith angle data taken between 1997 February 14 and June 8. The TeV emission from Mrk 501 was unprecedentedly high, allowing a statistically accurate spectrum to be derived. In contrast to previously measured TeV spectra, the spectrum over this energy region is not well described by a simple power law. Instead, the spectrum exhibits significant curvature and can be well fitted by a parabolic spectrum proportional to E-2.22+/-0.04+/-0.05-(0.47 +/- 0.07 log10 E), where the first set of errors is statistical and the second systematic and E is in units of TeV. Simple power-law fits to the TeV data are also inconsistent with upper limits from EGRET observations that temporally overlap a subset of the TeV observations. The data show a statistically significant signal above energies of 7 TeV. This energy, combined with variability timescales, yields a Doppler beaming factor, delta, of at least 1.5. C1 Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Univ Oxford, Dept Phys, Oxford, England. Univ Leeds, Dept Phys, Leeds LS2 9JT, W Yorkshire, England. Natl Univ Ireland Univ Coll Dublin, Expt Phys Dept, Dublin 4, Ireland. Washington Univ, Dept Phys, St Louis, MO 63130 USA. St Patricks Coll, Dept Phys, Maynooth, Kildare, Ireland. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. Loras Coll, Dubuque, IA 52004 USA. RP Samuelson, FW (reprint author), Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. EM dalewis@iastate.edu NR 34 TC 66 Z9 66 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP L17 EP L20 DI 10.1086/311454 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ948 UT WOS:000074785500004 ER PT J AU Gordon, SM Kirshner, RP Long, KS Blair, WP Duric, N Smith, RC AF Gordon, SM Kirshner, RP Long, KS Blair, WP Duric, N Smith, RC TI A new optical sample of supernova remnants in M33 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies, individual (M33); galaxies, ISM; radio continuum, galaxies; supernova remnants ID LARGE MAGELLANIC CLOUD; H-II REGIONS; EMISSION-LINE PROPERTIES; X-RAY; SPIRAL GALAXIES; NOVA REMNANTS; MORPHOLOGY; NUMBER; ATLAS; STARS AB We present a new and larger sample of supernova remnants in the nearby spiral galaxy M33. The sample is based upon CCD interference filter observations obtained with the Kitt Peak 4 m telescope and spectroscopic observations obtained with the Multiple Mirror Telescope. Using optical emission-line ratios, supplemented by a radio continuum map of M33 (Duric et al.; Gordon et al.), we have identified 98 supernova remnant (SNR) candidates, of which 53 were previously unknown. We have obtained spectra of 27 SNR candidates, bringing the total number of M33 SNRs for which spectra are available to 72. All the spectra show the characteristic signature of shock-heated gas, which leads us to believe that the rest of the candidates are also supernova remnants. The large sample provides a useful database to investigate the global properties of SNRs, In this paper, we present a new cumulative number-diameter [N( 1) maps of the bipolar outflow NGC 22646G SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atlases; ISM, individual (NGC 2264); ISM, jets and outflows; stars, formation ID SIS HETERODYNE RECEIVER; OB1 MOLECULAR CLOUD; CALIBRATION; TELESCOPE AB We describe detailed CO (2 --> 1) observations of NGC 2264G. This object is a highly collimated bipolar molecular outflow that has been completely mapped with moderately high resolution as described here. We present the data as an atlas of contoured channel maps and show spectra at numerous positions of importance. We show that at several positions in the low-velocity outflow lobes, the emission from the outflow dominates the emission within the velocity range of the line core. C1 Univ Waterloo, Dept Phys, Guelph Waterloo Program Grad Work Phys, Waterloo, ON N2L 3G1, Canada. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Fich, M (reprint author), Univ Waterloo, Dept Phys, Guelph Waterloo Program Grad Work Phys, Waterloo, ON N2L 3G1, Canada. NR 11 TC 4 Z9 4 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUL PY 1998 VL 117 IS 1 BP 147 EP 165 DI 10.1086/313109 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101DK UT WOS:000074854200005 ER PT J AU Knapp, GR Young, K Lee, E Jorissen, A AF Knapp, GR Young, K Lee, E Jorissen, A TI Multiple molecular winds in evolved stars. I. A survey of CO(2-1) and CO(3-2) emission from 45 nearby asymptotic giant branch stars SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE radio lines, stars; stars, AGB and post-AGB; stars, mass loss ID CIRCUMSTELLAR CO EMISSION; MASS-LOSS RATES; IRAS SURVEY DATA; CARBON STARS; SEMIREGULAR VARIABLES; LINE OBSERVATIONS; REVISED MODEL; BIPOLAR FLOW; DUST SHELL; CRL 618 AB This paper describes observations of a new phenomenon in evolved mass-losing asymptotic giant branch (AGB) stars: the presence of two winds with different expansion velocities. CO(2-1) and CO(3-2) line emission was observed for 45 AGE stars at high velocity resolution and double winds found in 20% of the sample. Highly asymmetric lines were found in six other stars. The data tentatively suggest that double winds occur when the star undergoes a change (pulsational mode, chemical composition) and that the very narrow components represent the onset of a new phase of mass loss. C1 Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Free Univ Brussels, B-1050 Brussels, Belgium. RP Knapp, GR (reprint author), Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. NR 66 TC 134 Z9 134 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUL PY 1998 VL 117 IS 1 BP 209 EP 231 DI 10.1086/313111 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 101DK UT WOS:000074854200007 ER PT J AU Isler, ML Isler, PR Whitney, BM AF Isler, ML Isler, PR Whitney, BM TI Use of vocalizations to establish species limits in antbirds (Passeriformes : Thamnophilidae) SO AUK LA English DT Article ID SAYORNIS-PHOEBE; EASTERN PHOEBE; FORMICARIIDAE; DIFFERENTIATION; COMPLEX; GENUS; SONGS AB We introduce an empirically derived methodology for the definition, measurement, and application of vocal characters in assessing species limits in the numerically important Neotropical family Thamnophilidae. On the basis of available evidence, we assume that vocalizations are innate and that all vocal characters have a role in maintenance of species integrity in thamnophilids. Vocalizations of eight syntopic pairs, the members of which resemble one another in both plumage and voice, were analyzed to identify diagnosable vocal characters. To be diagnosable, characters had to distinguish members of a pair unambiguously. Three of the eight pairs were diagnosable by three vocal characters, four pairs by four characters, and one pair by seven characters. Vocalizations differed most consistently by characters reflecting loudsong note structure, loudsong pace, and note structure of calls. In establishing species limits for allopatric antbird populations, we suggest that three vocal characters, the minimum number distinguishing the syntopic pairs, be used as a point of reference. Keeping this point of reference in mind, we recommend that multiple diagnosable vocal characters be present when vocalizations are a major factor in determining species limits in thamnophilid antbirds. To the extent that populations differ strongly in other characters (e.g. morphological, molecular, other behavioral), fewer vocal characters may suffice. The identification of multiple vocal characters as a point of reference, as opposed to individual characters (e.g, note shape) or vocalization types (e.g, the loudsong), allows for greater latitude in the diagnosis. A focus on the number of characters is appropriate given the possibility that the role and importance of vocalization types in species' repertoires may differ across groups of taxa. The methodology and results may also have application in the study of other avian groups in which vocalizations are innate, especially the suboscines. C1 Smithsonian Inst, Natl Museum Amer Hist, Div Birds, Washington, DC 20560 USA. Louisiana State Univ, Museum Nat Sci, Baton Rouge, LA 70803 USA. RP Isler, ML (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Div Birds, Washington, DC 20560 USA. EM piantbird@aol.com NR 42 TC 93 Z9 105 U1 1 U2 4 PU AMER ORNITHOLOGISTS UNION PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0004-8038 J9 AUK JI AUK PD JUL PY 1998 VL 115 IS 3 BP 577 EP 590 PG 14 WC Ornithology SC Zoology GA 101XP UT WOS:000074893700003 ER PT J AU Greenberg, R Cordero, PJ Droege, S Fleischer, RC AF Greenberg, R Cordero, PJ Droege, S Fleischer, RC TI Morphological adaptation with no mitochondrial DNA differentiation in the coastal plain Swamp Sparrow SO AUK LA English DT Article ID POLYGENIC MUTATION; BIRDS AB We estimated genetic differentiation between morphologically distinct tidal marsh populations of Swamp Sparrows (Melospiza georgiana nigrescens) and the more widespread inland populations (M. g, georgiana and M. g, ericrypta). The tidal marsh populations are consistently grayer with more extensive black markings (particularly in the crown), and their bills are larger. These differences are variously shared with other species of salt marsh birds and small mammals. We analyzed mitochondrial DNA sequences (5' end of control region, COII/t-lys/ATPase8, and ND2) of Swamp Sparrows and found low levels of genetic variation and no evidence of geographic structure. These results suggest a rapid and recent geographic expansion of Swamp Sparrows from restricted Pleistocene populations. Morphological differentiation has occurred without long-term genetic isolation suggesting that selection on the divergent traits is intense. The grayer and more melanistic plumage is probably cryptic coloration for foraging on tidal mud, which tends to be grayish as a result of the formation of iron sulfides, rather than iron oxides, under anaerobic conditions. C1 Smithsonian Inst, Natl Zool Pk, Smithsonian Migratory Bird Ctr, Washington, DC 20008 USA. Smithsonian Inst, Natl Zool Pk, Genet Mol Lab, Washington, DC 20008 USA. Patuxent Wildlife Res Ctr, US Geol Survey, Biol Resources Div, Laurel, MD 20708 USA. RP Greenberg, R (reprint author), Smithsonian Inst, Natl Zool Pk, Smithsonian Migratory Bird Ctr, Washington, DC 20008 USA. EM antwren@erols.com RI Cordero, Pedro /L-1016-2014 OI Cordero, Pedro /0000-0002-1371-8009 NR 35 TC 61 Z9 63 U1 1 U2 4 PU AMER ORNITHOLOGISTS UNION PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0004-8038 J9 AUK JI AUK PD JUL PY 1998 VL 115 IS 3 BP 706 EP 712 PG 7 WC Ornithology SC Zoology GA 101XP UT WOS:000074893700014 ER PT J AU Smith, NG AF Smith, NG TI In memoriam: Martin Humphrey Moynihan, 1928-1996 SO AUK LA English DT Biographical-Item C1 Smithsonian Trop Res Inst, Balboa, Ancon, Panama. RP Smith, NG (reprint author), Smithsonian Trop Res Inst, Balboa, Ancon, Panama. NR 1 TC 1 Z9 1 U1 0 U2 0 PU AMER ORNITHOLOGISTS UNION PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0004-8038 J9 AUK JI AUK PD JUL PY 1998 VL 115 IS 3 BP 755 EP 758 PG 4 WC Ornithology SC Zoology GA 101XP UT WOS:000074893700019 ER PT J AU Peterson, PM Ortiz-Diaz, JJ AF Peterson, PM Ortiz-Diaz, JJ TI Allelic variation in the amphitropical disjunct Muhlenbergia torreyi (Poaceae : Muhlenbergiinae) SO BRITTONIA LA English DT Article DE Muhlenbergia; allozymes; phytogeography; North America; South America; Poaceae ID NORTH-AMERICA; ERAGROSTIDEAE; POPULATIONS; PLANTS AB Muhlenbergia torreyi occurs in the southwestern United States, northern? Mexico, and northwestern Argentina. Allozyme data were used to evaluate genetic diversity within and among populations of this amphitropical disjunct species. Electrophoretic examination of 22 putative enzyme loci in 15 populations revealed high levels of genetic variation (P ranging from 64.7 to 82.4; H from 0.527 to 0.757) and high levels of genetic diversity (F ranging from -0.584 to -0.939). All populations possess high levels of heterogeneity (F,, approaching -1, mean of -0.837) and exhibit lower levels of genetic fixation among populations (F-ST mean of 0.127). A comparison of genetic identity values among populations from North and South America indicates that the genetic variation is slightly greater (I = 0.93) in North America than in South America (I = 0.96). A total of 51 alleles were shared among all populations, and four unique alleles were detected: two from North American populations and two from South America. It seems likely that Muhlenbergia torreyi has dispersed to South America recently, because the populations there are less variable. Chromosome numbers, not determined by the authors, of 2n = 20, 21 for M. torreyi and 2n = 80, 82 for M. arenicola are reported. Muhlenbegia arenicola is first reported from South America. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, Washington, DC 20560 USA. RP Peterson, PM (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Bot, NHB-166, Washington, DC 20560 USA. NR 32 TC 9 Z9 14 U1 0 U2 0 PU NEW YORK BOTANICAL GARDEN PI BRONX PA PUBLICATIONS DEPT, BRONX, NY 10458 USA SN 0007-196X J9 BRITTONIA JI Brittonia PD JUL-SEP PY 1998 VL 50 IS 3 BP 381 EP 391 DI 10.2307/2807780 PG 11 WC Plant Sciences SC Plant Sciences GA 135BV UT WOS:000076780900010 ER PT J AU Condit, R AF Condit, R TI Ecological implications of changes in drought patterns: Shifts in forest composition in Panama SO CLIMATIC CHANGE LA English DT Article; Proceedings Paper CT International Workshop on Potential Impacts of Climate Change on Tropical Forest Ecosystems CY APR 24-28, 1995 CL SAN JUAN, PUERTO RICO SP World Wildlife Fund, Int Inst Trop Forestry ID TROPICAL FORESTS; CLIMATIC-CHANGE; NEOTROPICAL FOREST; SOUTHERN INDIA; VEGETATION; TREE; COMMUNITY; IMPACT AB CO2 concentration is increasing, temperature is likely to rise, and precipitation patterns might change. Of these potential climatic shifts, it is precipitation that will have the most impact on tropical forests, and seasonal patterns of rainfall and drought will probably be more important than the total quantity of precipitation. Many tree species are limited in distribution by their inability to survive drought. In a 50 ha forest plot at Barro Colorado Island in Panama (BCI), nearly all tree and shrub species associated with moist microhabitats are declining in abundance due to a decline in rainfall and lengthening dry seasons. This information forms the basis for a simple, general prediction: drying trends can rapidly remove drought-sensitive species from a forest. If the drying trend continues at BCI, the invasion of drought-tolerant species would be anticipated, but computer models predict that it could take 500 or more years for tree species to invade and become established. Predicting climate-induced changes in tropical forest also requires geographic information on tree distribution relative to precipitation patterns. In central Panama, species with the most restricted ranges are those from areas with a short dry season (10-14 weeks): 26-39% of the tree species in these wet regions do not occur where it is drier. In comparison, just 11-19% of species from the drier side of Panama (18 week dry season) are restricted to the dry region. From this information, I predict that a four-week extension of the dry season could eliminate 25% of the species locally; a nine-week extension in very wet regions could cause 40% extinction. Since drier forests are more deciduous than wetter forests, satellite images that monitor deciduousness might provide a way to assess long-term forest changes caused by changes in drought patterns. I predict that increasing rainfall and shorter dry seasons would not cause major extinction in tropical forest, but that drying trends are a much greater concern. Longer dry seasons may cause considerable local extinction of tree species and rapid forest change, and they will also tend to exacerbate direct human damage, which tends to favor drought-adapted and invasive tree species in favor of moisture-demanding ones. C1 Smithsonian Trop Res Inst, Ctr Trop Forest Sci, Unit 0948, APO, AA 34002 USA. RP Condit, R (reprint author), Smithsonian Trop Res Inst, Ctr Trop Forest Sci, Unit 0948, APO, AA 34002 USA. NR 39 TC 89 Z9 98 U1 3 U2 28 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD JUL PY 1998 VL 39 IS 2-3 BP 413 EP 427 DI 10.1023/A:1005395806800 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 108TE UT WOS:000075280900013 ER PT J AU West, WR AF West, WR TI The National Museum of the American Indian (Smithsonian) SO CONNAISSANCE DES ARTS LA French DT Article C1 Smithsonian Inst, Natl Museum Am Indian, Washington, DC 20560 USA. RP West, WR (reprint author), Smithsonian Inst, Natl Museum Am Indian, Washington, DC 20560 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SOC FR PROMOTION ART PI PARIS PA 25 RUE DE PONTHIEU, 75008 PARIS, FRANCE SN 0293-9274 J9 CONNAISSANCE ARTS JI Connaiss. Arts PD JUL-AUG PY 1998 IS 552 BP 66 EP 73 PG 8 WC Art SC Art GA ZY985 UT WOS:000074683400107 ER PT J AU Ferrari, FD Benforado, A AF Ferrari, FD Benforado, A TI Relationships between arthrodial membrane formation and addition of setae to swimming legs 1-4 during development of Dioithona oculata, Ridgewayia klausruetzleri, Pleuromamma xiphias, and Temora longicornis (Copepoda) SO CRUSTACEANA LA English DT Article ID CALANOIDA; SEGMENTS; BELIZE AB Relationships between arthrodial membrane formation and the addition of setae to the exopod and endopod of swimming leg 3 of the cyclopoid copepod Dioithona oculata are derived from formation homologies during development. Based on this information, these relationships are inferred for the remaining swimming legs of the cyclopoid and the swimming legs of three calanoids, Ridgewayia klausruetzleri, Pleuromamma xiphias, and Temora longicornis. Most of the variation in setal numbers for a leg among the four copepods is expressed in the distal segment of each ramus. The most striking differences in architecture result from a delay or failure in expression of the arthrodial membranes which separate the proximal segment or the middle segment of the ramus from the distal segment. Inferring a composite model for relationships between arthrodial membrane formation and addition of setae to the exopod and endopod of a swimming leg is complicated by differences in swimming leg 1 and the remaining swimming legs which includes an earlier allocation of the proximal seta of the middle (third) segment to both rami of swimming leg 1. These developmental patterns are presumed to be derived, and the endopod of all thoracopods of the ancestral copepod immediately after the transformation of the leg bud is presumed to have been 2-segmented with one medial sera on the proximal segment. C1 Natl Museum Nat Hist, Dept Invertebrate Zool, MSC, MRC 534,Smithsonian Inst, Washington, DC 20560 USA. RP Ferrari, FD (reprint author), Natl Museum Nat Hist, Dept Invertebrate Zool, MSC, MRC 534,Smithsonian Inst, Washington, DC 20560 USA. NR 11 TC 11 Z9 12 U1 1 U2 1 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 JUL PY 1998 VL 71 BP 545 EP 564 DI 10.1163/156854098X00428 PN 5 PG 20 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 109ML UT WOS:000075326300005 ER PT J AU Winter, K Virgo, A AF Winter, K Virgo, A TI Elevated CO2 enhances growth in the rain forest understory plant, Piper cordulatum, at extremely low light intensities SO FLORA LA English DT Article DE atmospheric CO2; carbon dioxide fixation; growth; light; Piper cordulatum; tropical forest understory ID ATMOSPHERIC CO2; CARBON-DIOXIDE; DARK RESPIRATION; QUANTUM YIELD; C-4 PLANTS; ENRICHMENT; RESPONSES; FUTURE AB Seedlings of the rain forest understory shrub Piper cordulatum were grown for several months at ambient and elevated concentrations of atmospheric CO2. Photon flux density (PFD) during 12-h photoperiods was maintained at extremely low levels (< 10 mu mol m(-2) s(-1)). Despite these low PFDs, dry matter accumulation and leaf area production were increased in air containing elevated (approximately twice-ambient) CO2 concentrations compared to ambient air. In leaves that had developed in deep shade and at ambient CO2, rates of net CO2 uptake, measured at 6 mu mol photons m(-2)s(-1), were 30% higher at elevated than at ambient CO2. Rates of net CO2 loss in the dark were 10% lower at elevated than at ambient CO2. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Winter, K (reprint author), Smithsonian Trop Res Inst, POB 2072, Balboa, Panama. NR 20 TC 10 Z9 11 U1 2 U2 3 PU GUSTAV FISCHER VERLAG PI JENA PA VILLENGANG 2, D-07745 JENA, GERMANY SN 0367-2530 J9 FLORA JI Flora PD JUL PY 1998 VL 193 IS 3 BP 323 EP 326 PG 4 WC Plant Sciences; Ecology SC Plant Sciences; Environmental Sciences & Ecology GA 106UG UT WOS:000075168400007 ER PT J AU Benedix, GK McCoy, TJ Keil, K Bogard, DD Garrison, DH AF Benedix, GK McCoy, TJ Keil, K Bogard, DD Garrison, DH TI A petrologic and isotopic study of winonaites: Evidence for early partial melting, brecciation, and metamorphism SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID IIICD IRON-METEORITES; NOBLE-GASES; ORDINARY CHONDRITES; SILICATE INCLUSIONS; ACHONDRITES; MINERALOGY; ORIGIN; CLASSIFICATION; EVOLUTION; BEARING AB We have conducted detailed petrologic, chemical, and isotopic studies of winonaites to ascertain the genesis of this group of meteorites. Winonaites have reduced mineral compositions and mineralogy, and oxygen isotopic compositions distinct from primitive achondrite groups other than silicate inclusions in IAB and IIICD irons. However, winonaites differ from IAB and IIICD irons in that they lack the metallic matrices of the latter and consist mostly of silicates. On the basis of these criteria, Winona, Mount Morris (Wisconsin), Tierra Blanca, Pontlyfni, Y-74025, Y-75300, Y-8005, and QUE 94535 are winonaites and Y-75305 and Y-75261 may be winonaites. Winonaites are fine- to medium-grained, mostly equigranular rocks. Pondyfni and Mount Morris (Wisconsin) contain what appear to be relict chondrules. Several winonaites contain mm-sized areas that differ substantially in grain size and/or silicate mineralogy from the surrounding matrix. Fe,Ni-FeS veins are common in many winonaites. Mineral compositions are intermediate between E and H chondrites, and reduced sulfides are observed in low-FeO winonaites. Bulk major element compositions are roughly chondritic, although REE elements are fractionated. The Ar-39-Ar-40 ages of three winonaites range from greater than or equal to 4.40 Ga (Mount Morris, Wisconsin) to 4.54 Ga (Pontlyfni). Cosmic-ray exposure ages are similar to 20-80 Ma. Trapped noble gases in these winonaites resemble those in enstatite chondrites. We suggest that the winonaites formed from a chondritic precursor material unlike that of known chondrites in mineral and oxygen isotopic compositions, and this material may have been heterogeneous in composition. Extensive heating caused metamorphism and partial melting of both Fe,Ni-FeS and silicate material. Impact brecciation during cooling mixed lithologies with different thermal histories, and subsequent metamorphism produced recrystallization, grain growth, and reduction of mafic silicates. The Ar-39-Ar-40 ages indicate that cooling may have been more rapid than observed in IAB irons, although later resetting may have occurred. Copyright (C) 1998 Elsevier Science Ltd. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Smithsonian Inst, Natl Museum Nat Hist, MRC, Dept Mineral Sci, Washington, DC 20560 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Benedix, GK (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. OI Benedix, Gretchen/0000-0003-0990-8878 NR 65 TC 66 Z9 66 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUL PY 1998 VL 62 IS 14 BP 2535 EP 2553 DI 10.1016/S0016-7037(98)00166-5 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 121TY UT WOS:000076031100011 ER PT J AU Williams, CK Snyder, LM Barnes, E Zervos, OH AF Williams, CK Snyder, LM Barnes, E Zervos, OH TI Frankish Corinth: 1997 (Excavation results) SO HESPERIA LA English DT Article ID FORUM SOUTHWEST C1 Amer Sch Classical Studies Athens, Corinth Excavations, GR-10676 Athens, Greece. Smithsonian Inst, Natl Museum Nat Hist, Washington, DC 20560 USA. Witchita State Univ, Dept Anthropol, Witchita, KS 67260 USA. RP Williams, CK (reprint author), Amer Sch Classical Studies Athens, Corinth Excavations, 54 Souidias St, GR-10676 Athens, Greece. NR 74 TC 8 Z9 8 U1 0 U2 0 PU AMER SCHOOL CLASS STUDIES PI PRINCETON PA C/O INST FOR ADVANCED STUDY, PRINCETON, NJ 08540 USA SN 0018-098X J9 HESPERIA JI Hesperia PD JUL-SEP PY 1998 VL 67 IS 3 BP 223 EP + DI 10.2307/2668470 PG 0 WC Archaeology SC Archaeology GA 125WV UT WOS:000076260800001 ER PT J AU Ubelaker, DH Pap, I AF Ubelaker, DH Pap, I TI Skeletal evidence for health and disease in the Iron Age of northeastern Hungary SO INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY LA English DT Article DE northeastern Hungary; Iron Age; skeletal; morbidity C1 Smithsonian Inst, Dept Anthropol, Washington, DC 20560 USA. Hungarian Natural Hist Museum, H-1062 Budapest, Hungary. RP Ubelaker, DH (reprint author), Smithsonian Inst, Dept Anthropol, Washington, DC 20560 USA. NR 36 TC 8 Z9 9 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1047-482X J9 INT J OSTEOARCHAEOL JI Int. J. Osteoarchaeol. PD JUL-AUG PY 1998 VL 8 IS 4 BP 231 EP 251 DI 10.1002/(SICI)1099-1212(199807/08)8:4<231::AID-OA423>3.0.CO;2-B PG 21 WC Anthropology; Archaeology SC Anthropology; Archaeology GA 117BD UT WOS:000075759300002 ER PT J AU Buzas, MA Hayek, LAC AF Buzas, MA Hayek, LAC TI SHE analysis for biofacies identification SO JOURNAL OF FORAMINIFERAL RESEARCH LA English DT Article ID NORTH-AMERICA; FORAMINIFERA; DIVERSITY; PATTERNS AB Most quantitative methodologies for designating biofacies do so by ordering, in some way, all the possible similarities between stations along some gradient. The procedure is considered successful when the ordering produces mappable units (biofacies or biotopes), In contrast, SHE analysis for biofacies identification (SHEBI) serially accumulates contiguous stations and designates biofacies as groups of contiguous stations that exhibit the properties of known statistical distributions for biological communities, SHEBI identifies biological communities and always insures mappability. The number of species, S, the information function, H, and the measure of evenness, E, are related by the decomposition equation H = InS + InE. Each of these quantities is calculated as N, the number of individuals, is accumulated by adding successive samples (stations). In all cases, for a multispecies population (community) these variables form linear trends on a log scale. As N accumulates with each sample, S usually increases and the decomposition equation establishes constraints on H and InE. If H remains constant, then InE must decrease precisely as InS increases. If InE remains constant, then H must increase precisely as InS increases. If H increases and InE decreases as InS increases with accumulation, then the ratio InE/lnS may remain constant. Sometimes, InS and H increase while InE and InE/lnS decrease. Departures from linear trends indicate a mixture of communities and, hence, a new biofacies. The total population from 35 stations ranging in depth from 20m to 2696m in traverse 6 of Parker (1954) in the northeastern Gulf of Mexico was analyzed using the SHEBI technique. Seven biofacies were recognized. These biofacies compare favorably with the six recognized by Parker. However, the SHEBI procedure recognized three biofacies at depths shallower than 100m while Parker recognized one. At depths greater than 200m SHEBI recognized two biofacies while Parker recognized three. SHEBI establishes boundaries by examining departures from the linear trends expected for the statistical distribution describing a multispecies population or community. Thus, SHEBI provides us not only with a means of designating biofacies, but also with a quantitative definition of a community. C1 Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. Smithsonian Inst, Washington, DC 20560 USA. RP Buzas, MA (reprint author), Smithsonian Inst, Dept Paleobiol, NHB MRC-121, Washington, DC 20560 USA. NR 33 TC 49 Z9 51 U1 1 U2 6 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 1998 VL 28 IS 3 BP 233 EP 239 PG 7 WC Paleontology SC Paleontology GA 106XX UT WOS:000075177500006 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, NMNH MRC-121, 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 JUL PY 1998 VL 28 IS 3 BP 257 EP 259 PG 3 WC Paleontology SC Paleontology GA 106XX UT WOS:000075177500008 ER PT J AU Ko, YK Geiss, J Gloeckler, G AF Ko, YK Geiss, J Gloeckler, G TI On the differential ion velocity in the inner solar corona and the observed solar wind ionic charge states SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MINOR IONS; HEAVY-IONS; ACCELERATION; IONIZATION AB Theoretical calculations on multifluid solar wind have indicated that the velocities of ions of the same element are not the same in the inner coronal region where the freeze-in process of these solar wind heavy ions occurs. This may have nonnegligible effect on the inference of the electron temperature in this region from the observed ionic charge states. In this paper, we investigate the effect of differential ion velocities on the inferred freeze-in temperatures and the coronal electron temperature.diagnostics. We then investigate if the ionic charge state data are able to provide constraints on the differential velocities of these ions in their freezing-in region. We use the ionic charge composition data observed by the SWIGS instrument on Ulysses during the south polar pass as an example. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Int Space Sci Inst, Bern, Switzerland. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Ko, YK (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 22 TC 11 Z9 11 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1998 VL 103 IS A7 BP 14539 EP 14545 DI 10.1029/98JA00763 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZY130 UT WOS:000074589300003 ER PT J AU Kalfatovic, MR AF Kalfatovic, MR TI Portraits: Talking with artists at the met, the modern, the Louvre and elsewhere. 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 1998 VL 123 IS 12 BP 86 EP 87 PG 2 WC Information Science & Library Science SC Information Science & Library Science GA ZZ269 UT WOS:000074712500067 ER PT J AU Francis, J Boness, D Ochoa-Acuna, H AF Francis, J Boness, D Ochoa-Acuna, H TI A protracted foraging and attendance cycle in female Juan Fernandez fur seals SO MARINE MAMMAL SCIENCE LA English DT Article DE foraging; diving; otariid; fur seal; Arctocephalus philippii; maternal ID ZALOPHUS-CALIFORNIANUS; DIVING PATTERNS; SATELLITE; LIONS; TELEMETRY; BEHAVIOR; TRACKING; MILK AB Previous studies of fur seals suggest that the attendance patterns and consequent temporal patterning of energy transfer from mother to pup follows a latitudinal dine. While data from subpolar, tropical, and some temperate latitude species support the postulated dine, data for the temperate latitude Juan Fernandez fur seal do not. Maternal foraging trips and associated visits ashore were the longest of all otariids studied to date. The first foraging trip postpartum averaged 10.2 d (n = 51 females, range 1-22.5), foraging trips combined averaged 12.3 d (n = 100, range 1.0-25.0), and visits ashore averaged 5.3 d (n = 91, range 0.3-15.8) over the three seasons of study. Only duration of lactation was intermediate between subpolar and tropical strategies as predicted. Dive records suggest that these females feed almost exclusively at night at depths of less than 10 m and at distances of more than 500 km offshore. The prey species of this fur seal, primarily myctophids and squid, migrate to the surface at night and are patchily distributed. Foraging trip length varied between years in conjunction with shifts in sea-surface temperature and type of prey consumed. We suggest that distribution of prey, irrespective of latitude, dictates foraging patterns of fur seals and leads to the exceptionally long foraging trips and visits ashore observed in this species. C1 Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. Univ Florida, Dept Zool, Gainesville, FL 32611 USA. RP Francis, J (reprint author), Natl Geog Televis, 1145 17th St NW, Washington, DC USA. NR 66 TC 50 Z9 52 U1 1 U2 7 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1998 VL 14 IS 3 BP 552 EP 574 DI 10.1111/j.1748-7692.1998.tb00742.x PG 23 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA ZW533 UT WOS:000074420500008 ER PT J AU Krot, AN Petaev, MI Zolensky, ME Keil, K Scott, ERD Nakamura, K AF Krot, AN Petaev, MI Zolensky, ME Keil, K Scott, ERD Nakamura, K TI Secondary calcium-iron-rich minerals in the Bali-like and Allende-like oxidized CV3 chondrites and Allende dark inclusions SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID HIGH-TEMPERATURE CONDENSATION; CARBONACEOUS CHONDRITE; AQUEOUS ALTERATION; SOLAR NEBULA; COMPOSITIONAL CLASSIFICATION; METEORITE; OLIVINE; ORIGIN; RIMS; METAMORPHISM AB We have characterized Ca-Fe-rich silicates (salite-hedenbergite pyroxenes (Fs(10-50)Wo(45-50)), andradite (Ca3Fe2Si3O12), kirschsteinite (CaFeSiO4), and wollastonite (Ca3Si3O9)) in the type I chondrules and matrices in the Ball-like and Allende-like oxidized CV3 chondrites and Allende dark inclusions. In type I chondrules in the Ball-like CV3 chondrites, metal is oxidized to magnetite; magnetite-sulfide nodules are replaced by Ca-Fe-rich pyroxenes with minor andradite and pure fayalite. We infer that Ca-Fe-rich pyroxenes, andradite, fayalite, magnetite, and phyllosilicates (which occur in mesostases) formed at relatively low temperatures (<300 degrees C) in the presence of aqueous solutions. Thermodynamic analysis of phase relations in the Si-Fe-Ca-O-H system and large O isotopic fractionation of the coexisting magnetite and fayalite (similar to 20 parts per thousand) (Krot et al., 1998) are consistent with this interpretation. In type I chondrules in the Allende-like CV3 chondrites and dark inclusions, magnetite-sulfide nodules are replaced by Ca-Fe-rich pyroxenes and ferrous olivine; low-Ca pyroxene and forsterite phenocrysts are rimmed and veined by ferrous olivine. It appear that the Ca-Fe-rich pyroxenes predate formation of ferrous olivine; the latter postdates formation of talc and biopyriboles (Brearley, 1997). The Allende dark inclusions are crosscut by Ca-Fe-pyroxene-andradite veins and surrounded by Ca-rich rims that consist of Ca-Fe-rich pyroxenes, andradite, wollastonite, and kirschsteinite. Calcium-rich veins and rims formed after aggregation and lithification of the dark inclusions. The rimmed dark inclusions show zoned depletion in Ca, which is due to a lower abundance of Ca-Fe-rich pyroxenes close to the rim. Calcium was probably leached from the inclusions and redeposited along their edges. We infer that the Allende-like chondrites and dark inclusions experienced similar aqueous alteration to the Ball-like chondrites and were metamorphosed subsequently, which resulted in loss of aqueous solutions and dehydration of phyllosilicates. We conclude that Ca-Fe-rich silicates in the oxidized CV3 chondrites and Allende dark inclusions are secondary and resulted from aqueous fluid-rock interactions during progressive metamorphism of a heterogeneous mixture of hydrous (ices?) and anhydrous materials; the latter were possibly mineralogically similar to the reduced CV3 chondrites. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Lyndon B Johnson Space Ctr, Earth Sci & Solar Syst Explorat Div, Houston, TX 77058 USA. Kobe Univ, Div Earth & Planetary Sci, Kobe, Hyogo 657, Japan. RP Krot, AN (reprint author), Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. EM sasha@kahana.pgd.hawaii.edu NR 71 TC 57 Z9 57 U1 0 U2 12 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 JUL PY 1998 VL 33 IS 4 BP 623 EP 645 PG 23 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 114GV UT WOS:000075601500008 ER PT J AU Russell, SS McCoy, TJ Jarosewich, E Ash, RD AF Russell, SS McCoy, TJ Jarosewich, E Ash, RD TI The Burnwell, Kentucky, low iron oxide chondrite fall: Description, classification and origin SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID OXYGEN-ISOTOPE; MINERALOGY; METEORITES AB The Burnwell, Kentucky, meteorite fell as a single stone on 1990 September 4. The Burnwell meteorite has lower Fa in olivine (15.8 mol%), Fs in orthopyroxene (13.4 mol%), Co in kamacite (0.36 wt%), FeO from bulk chemical analysis (9.43 wt%), sind Delta(17)O (0.51 +/- 0.02 parts per thousand), and higher Fe, Ni, Co metal (19.75 wt% from bulk wet chemical analysis) than observed in H chondrites. The Burnwell meteorite plots on extensions of H-L-LL chondrite trends for each of these properties towards more reducing compositions than in H chondrites. Extensions of this trend have been previously suggested in the case of other low-FeO chondrites or silicate inclusions in the IIE iron Netschaevo, but interpretation of the evidence in these meteorites is complicated by terrestrial weathering, chemical disequilibrium or reduction. In contrast, the Burnwell meteorite is an equilibrated fall that exhibits no evidence for reduction. As such, it provides the first definitive evidence for extension of the H-L-LL ordinary chondrite trend beyond typical H values towards more reducing compositions. C1 Smithsonian Inst, Dept Mineral Sci, US Museum Nat Hist, Dept Mineral Sci,MRC 119, Washington, DC 20560 USA. Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. RP Russell, SS (reprint author), Nat Hist Museum, Dept Mineral, Cromwell Rd, London SW7 5BD, England. EM sarr@nhm.ac.uk NR 15 TC 11 Z9 12 U1 0 U2 1 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 JUL PY 1998 VL 33 IS 4 BP 853 EP 856 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 114GV UT WOS:000075601500031 ER PT J AU Ash, RD Connolly, HC Alexander, CMO MacPherson, GJ Rumble, D AF Ash, RD Connolly, HC Alexander, CMO MacPherson, GJ Rumble, D TI Oxygen-isotopic ratios of natural and synthetic chondrules: Evidence for in situ reduction by carbon. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID REDUCED CHONDRULES; CHONDRITES C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. CALTECH, Pasadena, CA 91125 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 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 JUL PY 1998 VL 33 IS 4 SU S BP A11 EP A11 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 117JK UT WOS:000075778000013 ER PT J AU MacPherson, GJ Ash, RD Rumble, D AF MacPherson, GJ Ash, RD Rumble, D TI In situ laser microanalysis of oxygen isotopes in ureilites. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 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 JUL PY 1998 VL 33 IS 4 SU S BP A96 EP A97 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 117JK UT WOS:000075778000174 ER PT J AU McCoy, TJ Dickinson, TL Lofgren, GE AF McCoy, TJ Dickinson, TL Lofgren, GE TI Partial melting of the Indarch (EH4) meteorite: Textural view of melting and melt migration. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID ORIGIN C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Natl Sci Fdn, Arlington, VA 22230 USA. Smithsonian Inst, Dept Mineral Sci, MRC 119, Washington, DC 20560 USA. EM mccoy.tim@nmnh.si.edu NR 10 TC 1 Z9 1 U1 0 U2 2 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 JUL PY 1998 VL 33 IS 4 SU S BP A100 EP A101 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 117JK UT WOS:000075778000182 ER PT J AU McKeegan, KD Leshin, LA MacPherson, GJ AF McKeegan, KD Leshin, LA MacPherson, GJ TI Oxygen-isotopic stratigraphy in a Vigarano type A calcium-aluminum-rich inclusion. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID RIMS; ALLENDE C1 Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. Univ Calif Los Angeles, Dept Earth & Planetary Sci, Los Angeles, CA 90095 USA. EM kdm@ess.ucla.edu RI McKeegan, Kevin/A-4107-2008 OI McKeegan, Kevin/0000-0002-1827-729X NR 10 TC 14 Z9 14 U1 0 U2 0 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1998 VL 33 IS 4 SU S BP A102 EP A103 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 117JK UT WOS:000075778000185 ER PT J AU Petaev, MI Wood, JA AF Petaev, MI Wood, JA TI The CWPI model of nebular condensation: Effects of pressure on the condensation sequence. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NR 4 TC 6 Z9 6 U1 0 U2 0 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 JUL PY 1998 VL 33 IS 4 SU S BP A122 EP A122 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 117JK UT WOS:000075778000220 ER PT J AU Wood, JA AF Wood, JA TI Constraints placed by aluminum-26 on early solar system history. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. NR 1 TC 2 Z9 2 U1 0 U2 0 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 JUL PY 1998 VL 33 IS 4 SU S BP A168 EP A169 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 117JK UT WOS:000075778000308 ER PT J AU Early, J AF Early, J TI Risk & opportunity - The museum as career choice - Opportunities for minorities SO MUSEUM NEWS LA English DT Article C1 Smithsonian Inst, Ctr Folklife Programs & Cultural Studies, Washington, DC 20560 USA. RP Early, J (reprint author), Smithsonian Inst, Ctr Folklife Programs & Cultural Studies, Washington, DC 20560 USA. NR 0 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 JUL-AUG PY 1998 VL 77 IS 4 BP 35 EP + PG 0 WC Art SC Art GA ZX062 UT WOS:000074465300012 ER PT J AU Laurance, WF AF Laurance, WF TI Fragments of the forest SO NATURAL HISTORY LA English DT Article C1 Biol Dynam Forest Fragments Project, Manaus, Amazonas, Brazil. Smithsonian Inst, Washington, DC 20560 USA. Univ Missouri, St Louis, MO 63121 USA. RP Laurance, WF (reprint author), Biol Dynam Forest Fragments Project, Manaus, Amazonas, Brazil. RI Laurance, William/B-2709-2012 NR 0 TC 1 Z9 1 U1 0 U2 0 PU NATURAL HISTORY MAGAZINE PI NEW YORK PA 36 WEST 25TH STREET, FIFTH FLOOR, NEW YORK, NY 10010 USA SN 0028-0712 J9 NAT HIST JI Nat. Hist. PD JUL-AUG PY 1998 VL 107 IS 6 BP 34 EP 38 PG 5 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA ZW065 UT WOS:000074370400012 ER PT J AU Lovejoy, T AF Lovejoy, T TI Afterword SO NATURAL HISTORY LA English DT Article C1 Smithsonian Inst, Washington, DC 20560 USA. World Bank, Washington, DC 20433 USA. RP Lovejoy, T (reprint author), Smithsonian Inst, 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 JUL-AUG PY 1998 VL 107 IS 6 BP 51 EP 51 PG 1 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA ZW065 UT WOS:000074370400017 ER PT J AU Zotz, G Budel, B Meyer, A Zellner, H Lange, OL AF Zotz, G Budel, B Meyer, A Zellner, H Lange, OL TI In situ studies of water relations and CO2 exchange of the tropical macrolichen, Sticta tomentosa SO NEW PHYTOLOGIST LA English DT Article DE lichen; rain forest; water content; photosynthesis; resaturation respiration; Panama ID RAIN-FOREST; FIELD-MEASUREMENTS; LICHEN; PHOTOSYNTHESIS; PATTERNS; HABITAT; DESERT AB Diel (24-h) time courses of CO2 exchange, water relations, and microclimate of the foliose lichen, Sticta tomentosa (Swartz) Ach., and responses to experimentally manipulated conditions were measured at a forest edge in a lower montane rainforest in Panama. Similar to earlier observations on two other rain forest lichens, daily desiccation suppressed net photosynthesis (NP) during the period when irradiation was highest. Not surprisingly, the light response curves of NP showed saturation at rather low light levels. Rehydration was associated with an initial resaturation burst of short duration, which could be demonstrated both under natural conditions and experimentally. This additional loss of CO2 seems too low to be ecologically relevant. Moreover, high thallus hydration was also detrimental to NP: at maximum water content net CO2 uptake was depressed by > 50%. Although NP was well adapted to the prevailing high temperatures, the latter also stimulated dark respiration. On average, almost 60 % of the diurnal carbon gain was lost during the night. In spite of these limitations, the integrated 24-h C gain was quite high, on average 0.5 % of the thallus C content. Whilst these figures were determined for horizontally exposed samples, we also assessed the role of different exposures on photosynthetic performance. Diel C gain was highest under conditions of semi-shade (westerly exposure), which allowed long periods of activity, whilst much higher irradiance at other exposures could not be utilized for photosynthetic production: easterly exposed thalli dried out even faster than horizontally exposed samples. C1 Univ Wurzburg, Julius von Sachs Inst Biowissensch, Lehrstuhl Bot 2, D-97082 Wurzburg, Germany. Smithsonian Trop Res Inst, Balboa, Panama. RP Zotz, G (reprint author), Univ Wurzburg, Julius von Sachs Inst Biowissensch, Lehrstuhl Bot 2, Julius von Sachs Pl 3, D-97082 Wurzburg, Germany. NR 31 TC 23 Z9 27 U1 1 U2 7 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0028-646X J9 NEW PHYTOL JI New Phytol. PD JUL PY 1998 VL 139 IS 3 BP 525 EP 535 DI 10.1046/j.1469-8137.1998.00215.x PG 11 WC Plant Sciences SC Plant Sciences GA 107VB UT WOS:000075230700010 ER PT J AU Andrade, JL Meinzer, FC Goldstein, G Holbrook, NM Cavelier, J Jackson, P Silvera, K AF Andrade, JL Meinzer, FC Goldstein, G Holbrook, NM Cavelier, J Jackson, P Silvera, K TI Regulation of water flux through trunks, branches, and leaves in trees of a lowland tropical forest SO OECOLOGIA LA English DT Article DE hydraulic conductance; sap flow; stomata; transpiration; tropical forest trees ID MIDDAY STOMATAL CLOSURE; XYLEM SAP FLOW; HYDRAULIC CONDUCTANCE; BETULA-OCCIDENTALIS; GROWING SUGARCANE; ROOT SIGNALS; RAIN-FOREST; TRANSPIRATION; LEAF; SOIL AB We studied regulation of whole-tree water use in individuals of five diverse canopy tree species growing in a Panamanian seasonal forest. A construction crane equipped with a gondola was used to access the upper crowns and points along the branches and trunks of the study trees for making concurrent measurements of sap flow at the whole-tree and branch levels, and vapor phase conductances and water status at the leaf level. These measurements were integrated to assess physiological regulation of water use from the whole-tree to the single-leaf scale. Whole-tree water use ranged from 379 kg day(-1) in a 35 m-tall Anacardium excelsum tree to 46 kg day(-1) in an 18 m-tall Cecropia longipes tree. The dependence of whole-tree and branch sap velocity and sap flow on sapwood area was essentially identical in the five trees studied. However, large differences in transpiration per unit leaf area (E) among individuals and among branches on the same individual were observed. These differences were substantially reduced when E was normalized by the corresponding branch leaf area:sapwood area ratio (LA/SA). Variation in stomatal conductance (g(s)) and crown conductance (g(c)), a total vapor phase conductance that includes stomatal and boundary layer components, was closely associated with variation in the leaf area-specific total hydraulic conductance of the soil/leaf pathway (G(t)). Vapor phase conductance in all five trees responded similarly to variation in G(t). Large diurnal variations in G(t) were associated with diurnal variation in exchange of water between the transpiration stream and internal stem storage compartments. Differences in stomatal regulation of transpiration on a leaf area basis appeared to be governed largely by tree size and hydraulic architectural features rather than physiological differences in the responsiveness of stomata. We suggest that reliance on measurements gathered at a single scale or inadequate range of scale may result in misleading conclusions concerning physiological differences in regulation of transpiration. C1 Hawaii Agr Res Ctr, Aiea, HI 96701 USA. Univ Hawaii, Dept Bot, Honolulu, HI 96822 USA. Univ Los Andes, Dept Ciencias Biol, Bogota, Colombia. Univ Calif Los Angeles, Dept Biol, Los Angeles, CA 90024 USA. Harvard Univ, Biol Labs, Cambridge, MA 02138 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Meinzer, FC (reprint author), Hawaii Agr Res Ctr, 99-193 Aiea Hts Dr, Aiea, HI 96701 USA. EM meinzer@hawaii.edu RI Meinzer, Frederick/C-3496-2012 NR 47 TC 95 Z9 105 U1 0 U2 27 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0029-8549 J9 OECOLOGIA JI Oecologia PD JUL PY 1998 VL 115 IS 4 BP 463 EP 471 DI 10.1007/s004420050542 PG 9 WC Ecology SC Environmental Sciences & Ecology GA 106KK UT WOS:000075128300003 PM 28308265 ER PT J AU Novotny, V Basset, Y AF Novotny, V Basset, Y TI Seasonality of sap sucking insects (Auchenorrhyncha, Hemiptera) feeding on Ficus (Moraceae) in a lowland rain forest in New Guinea SO OECOLOGIA LA English DT Article DE herbivores; host specificity; insect abundance; phenology; species diversity ID PAPUA-NEW-GUINEA; TROPICAL FORESTS; TEMPORAL VARIABILITY; SPECIES ABUNDANCE; BODY LENGTH; DIVERSITY; COMMUNITIES; HERBIVORY; PHENOLOGY; PATTERNS AB Sap-sucking insects (Auchenorrhyncha, Hemiptera) were sampled quantitatively from the foliage of 15 species of Ficus (Moraceae) in a lowland rain forest in Papua New Guinea. Continuous sampling throughout 12 months produced 61,777 individuals and 491 species. Two seasonality parameters, circular statistics and Lloyd's index, were calculated for 139 species with a sample size of more than 36 individuals. Most of the species were present in the adult stage for at least half of the year, and many of them continuously throughout the year. However, almost all species exhibited marked seasonal changes in abundance. The abundance peaks of species were scattered throughout most of the year, but more species reached their population maximum during the wet, especially early wet, season than during the dry season. Overall species richness and abundance of Auchenorrhyncha were also higher during the wet than the dry season. A significant correlation between seasonality and host specificity was revealed in the auchenorrhynchan community. In particular, species evenly distributed throughout the year had a tendency to feed on a larger number of Ficus species than seasonally more restricted species. The seasonality, and the seasonality versus specificity correlation, were independent of species abundance. Among the most abundant species (n > 300) there was a marginally significant negative correlation between abundance and host specificity, so that polyphagous species had, on average, larger populations than specialists. There was no similar correlation among rarer species. The Auchenorrhyncha comprises three feeding guilds, which were also analysed separately. The mesophyll-feeding guild exhibited more pronounced seasonality than the phloem- and xylem-feeders. This difference could be explained as a part of the overall correlation between seasonality and host specificity as mesophyll-feeders were significantly more host specific than the other two guilds. C1 Acad Sci Czech Republic, Inst Entomol, CR-37005 Ceske Budejovice, Czech Republic. Univ S Bohemia, Fac Biol, CR-37005 Ceske Budejovice, Czech Republic. Smithsonian Trop Res Inst, Balboa, Ancon, Panama. RP Novotny, V (reprint author), Acad Sci Czech Republic, Inst Entomol, Branisovska 31, CR-37005 Ceske Budejovice, Czech Republic. EM novotny@entu.cas.cz RI Basset, Yves/B-6642-2014; Novotny, Vojtech/G-9434-2014 OI Novotny, Vojtech/0000-0001-7918-8023 NR 64 TC 64 Z9 67 U1 1 U2 8 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0029-8549 J9 OECOLOGIA JI Oecologia PD JUL PY 1998 VL 115 IS 4 BP 514 EP 522 DI 10.1007/s004420050549 PG 9 WC Ecology SC Environmental Sciences & Ecology GA 106KK UT WOS:000075128300010 PM 28308272 ER PT J AU Macek, JH Cavagnero, MJ AF Macek, JH Cavagnero, MJ TI Demkov-Osherov model reformulated in terms of conventional scattering theory SO PHYSICAL REVIEW A LA English DT Article ID STURMIAN EXPANSION; GREEN-FUNCTION; IONIZATION; THRESHOLD; HYDROGEN AB One of the few exactly solvable time-dependent quantum-mechanics problems was first analyzed by Demkov and Osherov 30 years ago (Zh. Eksp. Teor. Fit. 53, 1589 (1967) [Sov. Phys. JETP 26, 916 (1968)]). This model problem describes the interaction of a set of approximate stationary states with an additional state whose energy, in zeroth approximation, is a linear function of time. The Demkov-Osherov model is reexamined here using conventional Fourier transform methods. Emphasis on forward propagation in time eliminates the need for a Laplace transform of the wave function, as well as the resultant choice of contours for the evaluation of transition amplitudes. The evolution operator for the model Hamiltonian is expressed in terms of a single, frequency-dependent Sturmian. Such Sturmian functions are of considerable current interest in the analysis of nonadiabatic phenomena. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. RP Macek, JH (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 14 TC 12 Z9 12 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1998 VL 58 IS 1 BP 348 EP 356 DI 10.1103/PhysRevA.58.348 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZZ998 UT WOS:000074790500049 ER PT J AU Cote, R Dalgarno, A AF Cote, R Dalgarno, A TI Photoassociation intensities and radiative trap loss in lithium SO PHYSICAL REVIEW A LA English DT Article ID BOSE-EINSTEIN CONDENSATION; LONG-RANGE STATES; SCATTERING LENGTH; LOSS COLLISIONS; SODIUM ATOMS; LI ATOMS; SPECTROSCOPY; TRANSITION; LI-6(2); LI-7(2) AB We interpret measurements of photoassociative spectroscopy in a gas of lithium atoms at ultralow temperatures in which photons are absorbed into high vibrational levels of excited electronic singlet and triplet states of Li-2. The excited vibrational levels decay by spontaneous emission into the vibrational continuum and the discrete vibrational levels of the ground singlet and lowest tripler electronic states. Spontaneous emission into discrete levels produces molecules that are no longer trapped, and decay into the vibrational continuum can produce atoms with sufficient kinetic energy to escape the trap. We present values of the efficiencies of trap loss by radiative excitation as a function of the trap depth for individual excited vibrational levels of the singlet and triplet states of the Li-6(2) and Li-7(2) molecules. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Cote, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 34 TC 49 Z9 49 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1998 VL 58 IS 1 BP 498 EP 508 DI 10.1103/PhysRevA.58.498 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZZ998 UT WOS:000074790500065 ER PT J AU Yuan, JM Esry, BD Morishita, T Lin, CD AF Yuan, JM Esry, BD Morishita, T Lin, CD TI Stable bound states of e(+)+Li and e(+)+Na SO PHYSICAL REVIEW A LA English DT Article ID SCATTERING; POSITRONS; LITHIUM AB Using model potentials to describe the ionic cores, we have approximated the e(+) +Li and e(+) + Na systems as quasi-three-body problems and performed adiabatic hyperspherical calculations to search for the existence of bound states. We have confirmed the existence of a bound state for e(+) + Li that was first predicted by Ryzhikh and Mitroy [Phys. Rev. Lett. 21, 4124 (1997)] with a binding energy of 58 meV. Further, we predict the existence of a stable bound state for e(+) + Na with a binding energy of 7 meV and explain why bound states exist for these two systems but not for the e(+) + H system, despite the fact that H- has a higher binding energy than either Li- or Na-. Based on this work, we find that it is unlikely that positrons can form stable bound states with any other of the alkali-metal atoms. C1 Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Natl Def Univ, Dept Appl Phys, Changsha, Peoples R China. RP Yuan, JM (reprint author), Kansas State Univ, Dept Phys, Cardwell Hall, Manhattan, KS 66506 USA. RI Lin, c d/D-7312-2012; Esry, Brett/H-7511-2013 OI Lin, c d/0000-0003-4847-8938; Esry, Brett/0000-0003-3207-8526 NR 13 TC 32 Z9 32 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1998 VL 58 IS 1 BP R4 EP R7 DI 10.1103/PhysRevA.58.R4 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZZ998 UT WOS:000074790500002 ER PT J AU Coltman, DW Bowen, WD Iverson, SJ Boness, DJ AF Coltman, DW Bowen, WD Iverson, SJ Boness, DJ TI The energetics of male reproduction in an acquatically mating pinniped, the harbour seal SO PHYSIOLOGICAL ZOOLOGY LA English DT Article ID ANTARCTIC FUR SEALS; HYDROGEN ISOTOPE-DILUTION; PHOCA-VITULINA; HALICHOERUS-GRYPUS; BODY-COMPOSITION; GRAY SEALS; ARCTOCEPHALUS-GAZELLA; ENERGY-REQUIREMENTS; URINARY LOSSES; HOODED SEALS AB The energy expenditure of breeding male harbour seals, Phoca vitulina, on Sable Island, Nova Scotia, was investigated by measuring changes in body mass, body composition, and water flux using isotope dilution. Seals lost 0.47% +/- 0.04% (n = 34) of their initial mass per day during the breeding season (4 wk), and fat, water, and protein accounted for 64.3% +/- 4.8%, 27.8% +/- 3.3%, and 6.9% +/- 1.4% of this mass loss, respectively (n = 31). Total energy expenditure was estimated as 33.3 +/- 1.9 MJ d(-1), or 3.9 +/- 0.2 W kg(-1) (n = 17), similar to rates measured in terrestrially mating pinniped species. However, unlike terrestrially mating pinnipeds, male harbour seals did not fast during the breeding season, and energy intake from foraging accounted for 61.8% +/- 4.0% of the total energy expended. Males derived most of their expended energy from food intake early in. the breeding season. However, as oestrus females became increasingly available, reduced rates of food intake in males were coupled with increased rates of total energy expenditure. Larger males expended significantly more energy from body stores and more total energy than smaller males. Male harbour seals appeared to balance the energetic costs of reproduction against the constraints of small body size by foraging during deep-diving trips before the appearance of oestrus females and by opportunistic feeding throughout the breeding season while at sea. We suggest that size dimorphism may be less pronounced in aquatically mating pinnipeds partly because the temporal and spatial separation of foraging and reproduction is less distinct than it is for terrestrially breeding pinnipeds. C1 Dalhousie Univ, Dept Biol, Halifax, NS B3J 4J1, Canada. Fisheries & Oceans Canada, Bedford Inst Oceanog, Marine Fish Div, Dartmouth, NS B24 4A2, Canada. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Coltman, DW (reprint author), Univ Edinburgh, Inst Cell Anim & Populat Biol, Edinburgh EH9 3JT, Midlothian, Scotland. EM david.coltman@ed.ac.uk RI Coltman, David/A-4453-2012; Bowen, William/D-2758-2012 OI Coltman, David/0000-0002-1268-2307; NR 44 TC 25 Z9 26 U1 2 U2 21 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0031-935X J9 PHYSIOL ZOOL JI Physiol. Zool. PD JUL-AUG PY 1998 VL 71 IS 4 BP 387 EP 399 DI 10.1086/515418 PG 13 WC Physiology; Zoology SC Physiology; Zoology GA ZY266 UT WOS:000074602900005 PM 9678499 ER PT J AU Flint, OS Bueno-Soria, J AF Flint, OS Bueno-Soria, J TI Studies of Neotropical caddisflies LVI: Descriptions of five new species of the genus Metrichia Ross (Trichoptera : Hydroptilidae) from Pakitza, Peru, with a checklist and bibliography of the described species of the genus SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE Metrichia; Trichoptera; Hydroptilidae; species list; bibliography; new species; Peru AB Five new species of the genus Metrichia from Peru are described, diagnosed and figured: M. pakitza, M. diosa, M. madre, M. adamsae, and M. helenae. Full generic status for Metrichia is accepted, the 58 described species are listed with their authors, date of publication and known distribution, and a bibliography presented for the papers in which the species were described or new country records given. 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, MRC 105, Washington, DC 20560 USA. NR 34 TC 8 Z9 9 U1 0 U2 1 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 1998 VL 100 IS 3 BP 489 EP 496 PG 8 WC Entomology SC Entomology GA 104WN UT WOS:000075039200013 ER PT J AU Adamski, D AF Adamski, D TI A new species of Pigritia Clemens (Lepidoptera : Gelechioidea : Coleophoridae) from Costa Rica SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE Lepidoptera; Gelechioidea; Blastobasini; Pigritia; Guanacaste; Costa Rica AB Pigritia marjoriella, n. sp., is described from localities along the northwestern coast and Cordillero de Guanacaste, Costa Rica. A photograph of the image and illustrations of wing venation and male and female genitalia are provided. C1 Smithsonian Inst, Dept Entomol, Washington, DC 20560 USA. RP Adamski, D (reprint author), Smithsonian Inst, Dept Entomol, MRC-105, Washington, DC 20560 USA. NR 5 TC 1 Z9 1 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 JUL PY 1998 VL 100 IS 3 BP 497 EP 503 PG 7 WC Entomology SC Entomology GA 104WN UT WOS:000075039200014 ER PT J AU Hooper, EJ AF Hooper, EJ TI Multiwavelength observations of quasars and their environments SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Hooper, EJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 83, Cambridge, MA 02138 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JUL PY 1998 VL 110 IS 749 BP 879 EP 879 DI 10.1086/316193 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ513 UT WOS:000074736900014 ER PT J AU Jordan, TE Weller, DE Correll, DL AF Jordan, TE Weller, DE Correll, DL TI Denitrification in surface soils of a riparian forest: Effects of water, nitrate and sucrose additions SO SOIL BIOLOGY & BIOCHEMISTRY LA English DT Article ID NITROUS-OXIDE; ACETYLENE INHIBITION; GROUNDWATER NITRATE; DYNAMICS; FIELD; EMISSIONS; REDUCTION; FIXATION; WETLAND; REMOVAL AB We studied the effects of adding water, nitrate and sucrose on denitrification ina riparian forest that receives nitrate in drainage from cornfields. We used large (3-5 m(2)) how-through chambers to sample N2O emissions from surface soils. N-2 emissions were estimated by comparing N2O efflux in chambers with or without acetylene addition. Water and solutions of nitrate or sucrose were sprinkled on the soil within the chambers and subsequent changes in N2O efflux were observed continuously for several days. In 23 of 25 cases the soil beneath the chambers released N2O at 0.19-17 mu g N2O-N m(-2) h(-1) prior to experimental treatments. In two chambers, there was consistent uptake of N2O from the atmosphere at 2.2 and 1.0 mu g N2O-N m(-2) h(-1) prior to treatments. Release of N2O was sometimes stimulated by adding water, usually stimulated by adding sucrose and always stimulated by adding nitrate. Stimulation by either nitrate and sucrose separately may reflect the heterogeneity of soil conditions that limit denitrification. After additions of nitrate or sucrose, N2O efflux rates usually peaked at more than 10 times pre-treatment rates, but effects of adding water were less pronounced. Responses to treatments began within minutes or hours and usually did not persist fbr more than a day. The rapid response suggests that denitrifiers possess a stock of enzymes ready to exploit rapidly changing conditions in the soil. Acetylene added to the air in the chambers penetrated at least 40 cm into the soil within 10 h, reaching concentrations of 3-8 ml l(-1) in the soil gas. Adding acetylene alone had no consistent effect on N2O flux. However, adding acetylene and nitrate together resulted in greater stimulation of N2O efflux than adding nitrate alone, presumably because acetylene inhibits N2O reduction to N-2 The lack of effect of acetylene alone suggests that inhibition of N2O reduction may not be effective in situ unless nitrate is also added. Based on the combined effects of acetylene and nitrate, we infer that 8.2-90% of the N2O produced after adding nitrate without acetylene was converted to N-2 The amount of N2O-N released after adding nitrate and acetylene was only 0.19-5.5% of the nitrate-N added. Published by Elsevier Science Ltd. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Jordan, TE (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. EM jordan@serc.si.edu OI Weller, Donald/0000-0002-7629-5437 NR 52 TC 29 Z9 33 U1 0 U2 19 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-0717 J9 SOIL BIOL BIOCHEM JI Soil Biol. Biochem. PD JUL PY 1998 VL 30 IS 7 BP 833 EP 843 DI 10.1016/S0038-0717(98)00013-3 PG 11 WC Soil Science SC Agriculture GA ZU774 UT WOS:000074233500001 ER PT J AU Ceruzzi, P AF Ceruzzi, P TI Transforming Computer Technology: Information processing for the pentagon, 1962-1986 SO TECHNOLOGY AND CULTURE LA English DT Book Review C1 Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. RP Ceruzzi, P (reprint author), Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. NR 1 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 0040-165X J9 TECHNOL CULT JI Technol. Cult. PD JUL PY 1998 VL 39 IS 3 BP 596 EP 598 PG 3 WC History & Philosophy Of Science SC History & Philosophy of Science GA 116BD UT WOS:000075700900050 ER PT J AU Parenti, LR Louie, KD AF Parenti, LR Louie, KD TI Neostethus djajaorum, new species, from Sulawesi, Indonesia, the first phallostethid fish (Teleostei : Atherinomorpha) known from east of Wallace's line SO RAFFLES BULLETIN OF ZOOLOGY LA English DT Article DE Phallostethidae; Sulawesi; Wallace's line; Dentatherinidae ID PLATE-TECTONICS; WESTERN PACIFIC; BORNEO; ORIGIN AB Neostethus djajaorum, new species, is described from specimens from the Gowa District near Ujung Pandang, Sulawesi. It is hypothesized to be most closely related to Neostethus robertsi from Luzon I., and Neostethus palawanenis from Palawan and Cuyo Is., the Philippines, with which it shares a distinctive, bifid or claw-shaped second ctenactinial bone in the intromittent organ of males. Neostethus djajaorum is distinguished from its closest relatives by the shape of the claw and extent of a bony projection and fleshy profile on the ventral margin of the first ctenactinium that abuts the claw. It is the first species in the distinctive atherinomorph fish family Phallostethidae known from east of Wallace's Line and from Sulawesi. The inferred ancestral distribution of the new species and its close relatives is coincident, in part, with limits of a now geographically dispersed ancient island-are system, the Sumba block or terrane, that comprises west Mindanao, northern Borneo (plus Palawan), east Kalimantan, the southwestern arm of Sulawesi and part of Java and the lesser Sunda Islands. The coastal and freshwater Phallostethidae and its sister taxon, the marine shorefish Dentatherinidae, have largely complementary (allopatric) distribution patterns that overlap (are sympatric) in northeastern Borneo and the Philippines, including portions of the Sumba terrane. C1 Smithsonian Inst, Natl Museum Nat Hist, NHB MRC 159, Div Fishes, Washington, DC 20560 USA. Univ Calif Los Angeles, Dept Biol, Los Angeles, CA 90095 USA. RP Parenti, LR (reprint author), Smithsonian Inst, Natl Museum Nat Hist, NHB MRC 159, Div Fishes, Washington, DC 20560 USA. NR 32 TC 12 Z9 12 U1 0 U2 6 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 JUN 30 PY 1998 VL 46 IS 1 BP 139 EP 150 PG 12 WC Zoology SC Zoology GA 111HZ UT WOS:000075432400014 ER PT J AU Kensley, B Clark, K AF Kensley, B Clark, K TI A new isopod species from Key Largo, Florida (Crustacea : Isopoda : Holognathidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID COAST AB Cleantioides verecundus is described from Thalassia seagrass rootmats found at Key Large, Florida. The species, the third from the western Atlantic, is characterized by the possession of a maxillipedal palp of five articles, three complete and one incomplete pleonite, and a subcircular posterior pleotelson bearing two rounded longitudinal ridges. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. Florida Inst Technol, Dept Biol Sci, Melbourne, FL 32901 USA. RP Kensley, B (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 10 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 JUN 24 PY 1998 VL 111 IS 2 BP 314 EP 319 PG 6 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 100BG UT WOS:000074793600009 ER PT J AU Ng, PKL Manning, RB AF Ng, PKL Manning, RB TI A new deep-water crab from Belau, Micronesia, with a key to the Pacific species of Chaceon (Crustacea : Decapoda : Brachyura : Geryonidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID GENUS CHACEON; SEA CRAB AB A new species of deep-water geryonid crab is described from Belau in Micronesia. It belongs to the Chaceon granulatus species group, but can be distinguished from other members of this group in possessing a relatively flatter carapace and proportionately more elongate male ambulatory legs. C1 Natl Univ Singapore, Sch Biol Sci, Singapore 119260, Singapore. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Ng, PKL (reprint author), Natl Univ Singapore, Sch Biol Sci, Kent Ridge, Singapore 119260, Singapore. RI Ng, Peter/J-7393-2012 NR 12 TC 6 Z9 6 U1 0 U2 3 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 JUN 24 PY 1998 VL 111 IS 2 BP 389 EP 397 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 100BG UT WOS:000074793600013 ER PT J AU Felder, DL Manning, RB AF Felder, DL Manning, RB TI A new ghost shrimp of the genus Lepidopthalamus from the Pacific coast of Colombia (Decapoda : Thalassinidea : Callianassidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID CRUSTACEA; SCHMITT; ECOLOGY AB Lepidophthalmus rafai is described from an intertidal shoreline in the vicinity of Buenaventura, Pacific coast of Colombia, South America. While recent collecting has uncovered populations assignable to described and undescribed species of the genus in intertidal habitats of the tropical eastern Pacific, most of these are forms with a ventrally plated or armed abdomen and a strongly trilobate posterior margin on the telson, features that suggest close relationship to L. bocourti (A. Milne Edwards) or L. eiseni Holmes. The new species is smaller in size than its congeners and is the most southerly distributed species of the genus known from the eastern Pacific. It lacks conspicuous sclerotized plates on ventral surfaces of the abdomen, a feature that it shares with a pair of antitropically distributed species in the western Atlantic. The two Atlantic forms, and the herein described new Pacific species, may have diverged from common stock partitioned by closing of the Panamanian Isthmus. The occurrence of L. rafai in a perturbated, hypoxic estuarine habitat is consistent with tolerances and adaptations documented previously for other species of the genus. C1 Univ SW Louisiana, Dept Biol, Lafayette, LA 70504 USA. Univ SW Louisiana, Lab Crustacean Res, Lafayette, LA 70504 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Felder, DL (reprint author), Univ SW Louisiana, Dept Biol, Lafayette, LA 70504 USA. NR 20 TC 9 Z9 11 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 JUN 24 PY 1998 VL 111 IS 2 BP 398 EP 408 PG 11 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 100BG UT WOS:000074793600014 ER PT J AU Blow, WC Manning, RB AF Blow, WC Manning, RB TI Eohalimede sandersi, the correct name for the species described as Eohalimede saundersi Blow & Manning, 1997 (Crustacea : Decapoda : Xanthidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Blow, WC (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. NR 1 TC 3 Z9 4 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD JUN 24 PY 1998 VL 111 IS 2 BP 409 EP 409 PG 1 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 100BG UT WOS:000074793600015 ER PT J AU Ludwig, CA AF Ludwig, CA TI Type locality and taxonomic status of Saltator plumbiceps "Baird, MS." Lawrence, 1867 (Aves : Passeriformes : Cardinalidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Due to an error in the published type locality for Saltator plumbiceps "Baird, MS." Lawrence, 1867, this name has long been considered a synonym of S coerulescens vigorsii Gray. It is, in fact, an older available name for the subspecies currently known as S. coerulescens richardsoni van Rossem. Van Rossem's richardsoni thus becomes a junior objective synonym of Lawrence's plumbiceps. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. RP Ludwig, CA (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. NR 9 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 JUN 24 PY 1998 VL 111 IS 2 BP 418 EP 419 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 100BG UT WOS:000074793600017 ER PT J AU Graves, GR AF Graves, GR TI Taxonomic notes on hummingbirds (Aves : Trochilidae). 1. Eriocnemis dyselius Elliot, 1872 is a melanistic specimen of Eriocnemis cupreoventris (Fraser, 1840) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID HELIANGELUS AB Eriocnemis dyselius Elliot, 1872 is hypothesized to be a melanistic specimen of Eriocnemis cupreoventris (Fraser, 1840), a puffleg hummingbird restricted to the Andes Mountains of Colombia and Venezuela. 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. NR 25 TC 5 Z9 5 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 JUN 24 PY 1998 VL 111 IS 2 BP 420 EP 424 PG 5 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 100BG UT WOS:000074793600018 ER PT J AU Lucas, SG Emry, RJ Foss, SE AF Lucas, SG Emry, RJ Foss, SE TI Taxonomy and distribution of Daeodon, an Oligocene-Miocene entelodont (Mammalia : Artiodactyla) from North America SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Dinohyms Peterson, 1906, the widely used generic name of the giant Oligocene-Miocene entelodont from North America, is a junior subjective synonym of Daeodon Cope, 1879. Ammodon Marsh, 1893 also is a junior subjective synonym of Daeodon. Five species have been named that we assign to Daeodon; D. shoshonensis Cope, 1879, D. leidyanus (Marsh, 1893), D. mento (Allen, 1926), D. hollandi (Peterson, 1905b), and D. minor (Loomis, 1932), and we tentatively consider all to represent a single species, D. shoshonensis Cope, 1879. The type material of D. leidyanus, from the basal Kirkwood Formation near Farmingdale, New Jersey is of early Miocene (late Arikareean) age. Other Daeodon occurrences range in age from late Oligocene (Arikareean) to early Miocene (Hemingfordian). C1 New Mexico Museum Nat Hist & Sci, Albuquerque, NM 87104 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. No Illinois Univ, Dept Biol Sci, De Kalb, IL 60115 USA. RP Lucas, SG (reprint author), New Mexico Museum Nat Hist & Sci, 1801 Mt Rd NW, Albuquerque, NM 87104 USA. NR 38 TC 0 Z9 0 U1 2 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 JUN 24 PY 1998 VL 111 IS 2 BP 425 EP 435 PG 11 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 100BG UT WOS:000074793600019 ER PT J AU van Dokkum, PG Franx, M Kelson, DD Illingworth, GD Fisher, D Fabricant, D AF van Dokkum, PG Franx, M Kelson, DD Illingworth, GD Fisher, D Fabricant, D TI The color-magnitude relation in CL 1358+62 at z=0.33: Evidence for significant evolution in the S0 population SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, individual (CL 1358 + 62); galaxies, elliptical and lenticular, cD; galaxies, evolution; galaxies, photometry; galaxies, spiral ID EARLY-TYPE GALAXIES; COMA CLUSTER; PRECISION PHOTOMETRY; ELLIPTIC GALAXIES; DISTANT CLUSTERS; VIRGO CLUSTERS; STAR-FORMATION; UNIVERSALITY; SUBSTRUCTURE; REDSHIFT AB We use a large, multicolor mosaic of HST WFPC2 images to measure the colors and morphologies of 194 spectroscopically confirmed members of the rich galaxy cluster CL 1358 + 62 at z = 0.33. We study the color-magnitude (CM) relation as a function of radius in the cluster to a limit of 416 from the center, equivalent to 1.6 h(50)(-1) Mpc. The intrinsic scatter in the rest-frame B-V CM relation of the elliptical galaxies is very small, similar to 0.022 mag. The CM relation of the ellipticals does not depend significantly on the distance from the cluster center. In contrast, the CM relation for the SO galaxies does depend on radius: the SO's in the core follow a CM relation similar to that of the ellipticals, but at large radii (R > 0.7 h(50)(-1) Mpc) the SO's are systematically bluer and the scatter in the CM relation approximately doubles, to similar to 0.043 mag. The blueing of the SO's at large radii is significant at the 95% confidence level. These results imply that the SO galaxies in the outer parts of the cluster have formed stars more recently than the SO's in the inner parts. A likely explanation is that clusters at z = 0.33 continue to accrete galaxies and groups from the field and that infall extinguishes star formation. The apparent homogeneity of the elliptical galaxy population implies that star formation in recently accreted ellipticals was terminated well before accretion occurred. We have constructed models to explore the constraints that these observations place on the star formation history of cluster galaxies. The best-constrained parameter is the scatter in the luminosity-weighted age Delta tau(L)/, which is less than 18% for the ellipticals and the SO's in the cluster core, and less than 35% for the SO's in the outer parts of the cluster. The constraints on the most recent period of star formation are model dependent, but we show that star formation in ellipticals likely ceased at z = 0.6 or higher. If we assume that the galaxies have a constant star formation rate up to a randomly distributed truncation time, we find that the SO's in the outer parts of the cluster have experienced star formation until the epoch of observation at z = 0.33. We conclude that the population of SO's in clusters is likely to evolve as star-forming galaxies are converted into passively evolving galaxies. Assuming a constant accretion rate after z = 0.33, we estimate that similar to 15% of the present-day early-type galaxy population in rich clusters was accreted between z = 0.33 and z = 0. The ellipticals land the brightest SO's) are probably a more stable population, at least since z = 0.6. C1 Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02318 USA. RP van Dokkum, PG (reprint author), Kapteyn Astron Inst, POB 800, NL-9700 AV Groningen, Netherlands. NR 63 TC 170 Z9 170 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1998 VL 500 IS 2 BP 714 EP 737 DI 10.1086/305762 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZX419 UT WOS:000074513900017 ER PT J AU Phelps, RL Sakai, S Freedman, WL Madore, BF Saha, A Stetson, PB Kennicutt, RC Mould, JR Ferrarese, L Ford, HC Gibson, BK Graham, JA Han, MS Hoessel, JG Huchra, JP Hughes, SM Illingworth, GD Silbermann, NA AF Phelps, RL Sakai, S Freedman, WL Madore, BF Saha, A Stetson, PB Kennicutt, RC Mould, JR Ferrarese, L Ford, HC Gibson, BK Graham, JA Han, MS Hoessel, JG Huchra, JP Hughes, SM Illingworth, GD Silbermann, NA TI The Hubble Space Telescope Extragalactic Distance Scale Key Project. IX. The discovery of Cepheids in NGC 2090 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; galaxies, distances and redshifts; galaxies, individual (NGC 2090); galaxies, photometry ID ABSOLUTE PEAK BRIGHTNESS; NEARBY GALAXIES; CCD PHOTOMETRY; CONSTANT; M100; H(0) AB We report on the discovery of 34 Cepheid variables in NGC 2090, with periods ranging between 5 and 58 days. Apparent V and I period-luminosity relations for Cepheids with P greater than or equal to 10 days have been constructed, assuming a fiducial distance modulus, mu(0), of 18.50 +/- 0.10 mag and a reddening, E(B - V), of 0.10 mag for the Large Magellanic Cloud. Using the ALLFRAME photometry package, an inferred reddening of E(V-I) = 0.09 +/- 0.02 mag (internal error) and a true distance modulus of 30.45 +/- 0.16 (random) +/- 0.16 (systematic) mag for NGC 2090 are found. The corresponding distance is 12.3 +/- 0.9 (random) +/- 0.9 (systematic) Mpc, a value that agrees at the 2.5% level with that derived from an independent analysis using a modified version of the DoPHOT photometry package. C1 Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. CALTECH, IPAC 100 22, Pasadena, CA 91125 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Inst Adv Studies, Weston, ACT 2611, Australia. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Royal Greenwich Observ, Cambridge CB3 0HA, England. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. RP Phelps, RL (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 54 TC 24 Z9 24 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1998 VL 500 IS 2 BP 763 EP 788 DI 10.1086/305766 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZX419 UT WOS:000074513900020 ER PT J AU Cohen, E Piran, T Narayan, R AF Cohen, E Piran, T Narayan, R TI The hardness distribution of gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; methods : data analysis ID BATSE AB It is often stated that gamma-ray bursts (GRBs) have typical energies of several hundred keV, where the typical energy may be characterized by the hardness H, the photon energy corresponding to the peak of nu F-nu. Among the 54 BATSE bursts analyzed by Band et al. in 1993 and the 136 analyzed by us, more than 60% have 50 keV < H < 300 keV. Is the narrow range of H a real feature of GRBs, or is it due to an observational difficulty in detecting harder bursts? We consider a population of standard candle bursts with a hardness distribution rho(H)d log H proportional to H(gamma)d log H and no luminosity-hardness correlation. We model the detection algorithm of BATSE as a function of H, including cosmological effects, detector characteristics, and triggering procedure, and we calculate the expected distribution of H in the observed sample for various values of gamma. Both samples show a paucity of soft (X-ray) bursts, which may be real. However, we find that the observed samples are consistent with a distribution above H = 120 keV with gamma similar to -0.5 (a slowly decreasing number of GRBs per decade of hardness). Thus, we suggest that a large population of unobserved hard gamma-ray bursts may exist. C1 Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Cohen, E (reprint author), Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. OI Narayan, Ramesh/0000-0002-1919-2730 NR 7 TC 9 Z9 9 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1998 VL 500 IS 2 BP 888 EP 892 DI 10.1086/305768 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZX419 UT WOS:000074513900031 ER PT J AU Quataert, E AF Quataert, E TI Particle heating by Alfvenic turbulence in hot accretion flows SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; MHD; plasmas; turbulence; waves ID ADVECTION-DOMINATED ACCRETION; STOCHASTIC PROTON ACCELERATION; IMPULSIVE SOLAR-FLARES; INTERSTELLAR TURBULENCE; MAGNETOHYDRODYNAMIC TURBULENCE; MAGNETIC-FIELD; BLACK-HOLES; CYGNUS X-1; DISKS; SIMULATIONS AB Recent work on Alfvenic turbulence by Goldreich & Sridhar (GS) suggests that the energy cascades almost entirely perpendicular to the local magnetic field. As a result, the cyclotron resonance is unimportant in dissipating the turbulent energy. Motivated by the GS cascade, we calculate the linear collisionless dissipation of Alfven waves with frequencies much less than the proton cyclotron frequency, but with perpendicular wavelengths of order the Larmor radius of thermal protons. In plasmas appropriate to hot accretion flows (proton temperature much greater than electron temperature), the dissipated Alfven wave energy primarily heats the protons. For a plasma with beta less than or similar to 5, however, where B is the ratio of the gas pressure to the magnetic pressure, the MHD assumptions utilized in the GS analysis break down before most of the energy in Alfven waves is dissipated; how the cascade then proceeds is unclear. Hot accretion flows, such as advection-dominated accretion flows (ADAFs), are expected to contain significant levels of MHD turbulence. This work suggests that, for beta greater than or similar to 5, the Alfvenic component of such turbulence primarily heats the protons. Significant proton heating is required for the viability of ADAF models. We contrast our results on particle heating in ADAFs with recent work by Bisnovatyi-Kogan & Lovelace. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Quataert, E (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 54 TC 112 Z9 113 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1998 VL 500 IS 2 BP 978 EP 991 DI 10.1086/305770 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZX419 UT WOS:000074513900040 ER PT J AU Yan, M Dalgarno, A AF Yan, M Dalgarno, A TI H-3(+) emission in the ejecta of SN 1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; infrared : stars; supernovae : individual (SN 1987A) ID THRESHOLD VIBRATIONAL-EXCITATION; SUPERNOVA 1987A; ELECTRON-IMPACT; FE-II; ROVIBRATIONAL INTENSITIES; SN-1987A; CO; LINE; HYDROGEN; ATOMS AB We present a chemical and thermal model of the envelope of SN 1987A. We assume that half of the hydrogen envelope is broken into many dense clumps and mixed into the inner region. For a range of densities and energy deposition rates, we find two phases, one with a temperature of about 7000 K and another with a temperature of about 3000 K. We suggest that the H-3(+) features originate in the low-temperature clumps. In them, the cooling is mainly through CO vibrational emission, and the H-3(+) vibrational levels are in LTE. Emission features observed at 3.41 and 3.53 mu m can be reproduced satisfactorily by H-3(+) fundamental band emission at a temperature of 2000 K when absorption by telluric water vapor is taken into account. The model is successful in predicting the dependence on time of the emission features. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Toledo, Ritter Observ, Toledo, OH 43606 USA. EM yan@cfa.160.harvard.edu; adalgarno@cfa.harvard.edu NR 45 TC 6 Z9 6 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 JUN 20 PY 1998 VL 500 IS 2 BP 1049 EP 1054 DI 10.1086/305769 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZX419 UT WOS:000074513900046 ER PT J AU Claussen, MJ Diamond, PJ Braatz, JA Wilson, AS Henkel, C AF Claussen, MJ Diamond, PJ Braatz, JA Wilson, AS Henkel, C TI The water masers in the elliptical galaxy NGC 1052 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 1052); galaxies : ISM; galaxies : nuclei; masers; radio lines : galaxies ID BLACK-HOLE; NGC-1052; H2O; EMISSION AB Very luminous water masers have been detected toward only two elliptical galaxies; the emission lines are relatively bread (approximate to 90 km s(-1)) and smooth, unlike the narrow maser spikes seen in other active galaxies. We have made the first VLBI observations of the water masers in one of these galaxies, NGC 1052. We find that the masers lie along, rather than perpendicular to, the jet. The scale of the maser emission is about 400 mu as (7000 AU). The masers could be associated with the radio jet, and we show that the jet is energetically capable of powering the observed maser emission by driving slow, nondissociative shocks into circumnuclear, dense molecular clouds. Alternatively, the masers could represent the amplification of the radio continuum emission of the jet by foreground molecular clouds. Further VLBI observations should be able to distinguish between these two possibilities. C1 Natl Radio Astron Observ, Socorro, NM 87801 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Radio Astron Observ, Green Bank, WV 24944 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Max Planck Inst Radioastron, D-53121 Bonn, Germany. RP Claussen, MJ (reprint author), Natl Radio Astron Observ, POB 0, Socorro, NM 87801 USA. NR 24 TC 32 Z9 33 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1998 VL 500 IS 2 BP L129 EP L132 DI 10.1086/311405 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZX422 UT WOS:000074514200012 ER PT J AU Stanek, KZ Zaritsky, D Harris, J AF Stanek, KZ Zaritsky, D Harris, J TI A "short" distance to the large magellanic cloud with the Hipparcos calibrated red clump stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : distances and redshifts; galaxies : individual (Large Magellanic Cloud); solar neighborhood; stars : horizontal-branch ID GALACTIC BAR; MAGNITUDE; BULGE AB Following an approach developed by Paczynski & Stanek, we derive a distance to the Large Magellanic Cloud (LMC) by comparing red clump stars from the Hipparcos catalog with the red clump stars observed in two fields in the LMC that were selected from the ongoing photometric survey of the Magellanic Clouds to lie in low-extinction regions. The use of red clump stars allows a single step determination of the distance modulus to the LMC, mu(0,LMC) = 18.065 +/- 0.031 +/- 0.09 mag (statistical plus systematic error), and the corresponding distance, R-LMC = 41.02 +/- 0.59 +/- 1.74 kpc. This measurement is in excellent agreement with the recent determination by Udalski et al., also based on the red clump stars, but is similar to 0.4 mag smaller than the generally accepted value of mu(0,LMC) = 18.50 +/- 0.15 mag, We discuss possible reasons for this discrepancy and how it can be resolved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. UCO, Lick Observ, Santa Cruz, CA 95064 USA. RP Stanek, KZ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS20, Cambridge, MA 02138 USA. EM kstanek@cfa.harvard.edu; dennis@ucolick.org; jharris@ucolick.org NR 40 TC 46 Z9 47 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1998 VL 500 IS 2 BP L141 EP L144 DI 10.1086/311420 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZX422 UT WOS:000074514200015 ER PT J AU Hagedorn, M Mack, AF Evans, B Fernald, RD AF Hagedorn, M Mack, AF Evans, B Fernald, RD TI The embryogenesis of rod photoreceptors in the teleost fish retina, Haplochromis burtoni SO DEVELOPMENTAL BRAIN RESEARCH LA English DT Article DE retina; development; teleost; cone photoreceptor; rod photoreceptor; Muller cell; GABA; vimentin ID FLOUNDER PSEUDOPLEURONECTES-AMERICANUS; NEONATAL RABBIT RETINA; OUTER PLEXIFORM LAYER; GOLDFISH RETINA; IMMUNOREACTIVE NEURONS; POSTNATAL-DEVELOPMENT; MOUSE RETINA; GABA; LARVAL; ZEBRAFISH AB Development of the retina, like that of other tissues, occurs via an orderly sequence of cell division and differentiation, producing the functional retina. In teleost fish, however, cell division and differentiation in the retina continue throughout the life of the animal in two distinct ways. Stem cells in a circumferential germinal zone at the periphery of the retina give rise to all retinal cell types and progenitor cells located throughout the retina in the outer nuclear layer (ONL) produce new rod photoreceptors. These processes in adult retina recapitulate in space the embryonic events responsible for forming the retina. Analysis of these events in an African cichlid fish, Haplochromis burtoni, confirmed that cone photoreceptors differentiate first, followed by rod photoreceptors. Correspondingly, at the margin of the eye, cone photoreceptors differentiate nearer to the margin than do rods. Control of photoreceptor production is not understood. Here we present the time of appearance and distribution pattern of GABA and vimentin which are candidates for the control of retinal cell division and differentiation. Antibody staining reveals that both GABA and vimentin exhibit unique patterns of expression during embryonic retinal development. Vimentin immunoreactivity is evident throughout the retina in a spoke-like pattern between developmental Days 4 and 7, as both cone and rod photoreceptors are being formed. GABA is expressed in horizontal cells between Days 5 and 7, corresponding to the onset of rod differentiation in time and in position within the retina. Moreover, the wave of GABAergic staining in the horizontal cells parallels the wave of rod differentiation across the embryonic retina of H. burtoni. Thus, GABA may play a role in the development of rod photoreceptors. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Oregon, Inst Neurosci, Eugene, OR 97403 USA. RP Hagedorn, M (reprint author), Smithsonian Inst, Natl Zool Pk, Dept Reprod Physiol, 3001 Conn Ave NW, Washington, DC 20008 USA. NR 43 TC 22 Z9 23 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-3806 J9 DEV BRAIN RES JI Dev. Brain Res. PD JUN 15 PY 1998 VL 108 IS 1-2 BP 217 EP 227 DI 10.1016/S0165-3806(98)00051-0 PG 11 WC Developmental Biology; Neurosciences SC Developmental Biology; Neurosciences & Neurology GA 103JQ UT WOS:000075154100021 ER PT J AU Irvine, WM Bergin, DA Dickens, JE Jewitt, D Lovell, AJ Matthews, HE Schloerb, FP Senay, M AF Irvine, WM Bergin, DA Dickens, JE Jewitt, D Lovell, AJ Matthews, HE Schloerb, FP Senay, M TI Chemical processing in the coma as the source of cometary HNC SO NATURE LA English DT Article ID ABUNDANCE RATIO; HCN AB The discovery of hydrogen isocyanide (HNC) in comet Hyakutake with an abundance (relative to hydrogen cyanide, KCN) similar to that seen in dense interstellar clouds raised the possibility that these molecules might be surviving interstellar material(1). The preservation of material from the Sun's parent molecular cloud would provide important constraints on the processes that took place in the protostellar nebula. But another possibility is that HNC is produced by photochemical processes in the coma, which means that its abundance could not be used as a direct constraint on conditions in the early Solar System. Here we show that the HNC/HCN ratio determined for comet Hale-Bopp varied with heliocentric distance in a way that matches the predictions of models of gas-phase chemical production of HNC in the coma, but cannot be explained if the HNC molecules were coming from the comet's nucleus. We conclude that HNC forms mainly by chemical reactions in the coma, and that such reactions need to be considered when attempting to deduce the composition of the nucleus from observations of the coma. C1 Univ Massachusetts, Five Coll Radio Astron Observ, Amherst, MA 01003 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Ottawa, ON K1A 0R6, Canada. Joint Astron Ctr, Hilo, HI 96720 USA. RP Irvine, WM (reprint author), Univ Massachusetts, Five Coll Radio Astron Observ, 619 LGRC, Amherst, MA 01003 USA. NR 26 TC 56 Z9 56 U1 0 U2 5 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD JUN 11 PY 1998 VL 393 IS 6685 BP 547 EP 550 DI 10.1038/31171 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZT988 UT WOS:000074150100043 PM 9634231 ER PT J AU Sartoretti, P Brown, RA Latham, DW Torres, G AF Sartoretti, P Brown, RA Latham, DW Torres, G TI A search for substellar companions around nine weak-lined T-Tauri stars with the Planetary Camera 2 of the Hubble Space Telescope SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : pre-main sequence; stars : imaging; stars : low-mass, brown dwarfs; planetary systems ID MAIN-SEQUENCE STARS; CALIBRATION; SPECTRUM; DWARFS AB To search for substellar companions, we have obtained I-band images of 9 weak-lined T-Tauri stars in the Taurus-Auriga star-forming region using the Planetary Camera 2 of the Hubble Space Telescope. Except for a stellar companion close to HBC 407, we found no companions within 8 " of any of our targets. We did find 23 faint objects outside a separation of 8 ". For 12 of these, we have color information that implies they are background objects. Our sensitivity limit for companions separated by more than 1 " is better than Delta I = 10 mag. This limit degrades to Delta I = 5 mag at a separation of about 0.2 ". For the median apparent magnitude, I = 11 mag, and median age, 10(7) yr, of our targets, the above sensitivity limits correspond to companions with 18 and 55 Jupiter masses, respectively. To complement the imaging program, radial-velocity observations of the 9 stars were obtained using the Center for Astrophysics Digital Speedometers. There is a hint of a longterm acceleration of about 2 km s(-1) over ten years in the radial velocity of HBC 407, consistent with the evidence for a close companion to HBC 407 found in the HST images. In addition, one of our targets, HBC 392 was found to be a double-lined spectroscopic binary. C1 Inst Astrophys, F-75014 Paris, France. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Sartoretti, P (reprint author), Inst Astrophys, 98 Bis Blvd Arago, F-75014 Paris, France. EM sartoret@iap.fr NR 30 TC 18 Z9 18 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN 10 PY 1998 VL 334 IS 2 BP 592 EP 598 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZW909 UT WOS:000074460500031 ER PT J AU van Noort, M Lanz, T Lamers, HJGLM Kurucz, RL Ferlet, R Hebrard, G Vidal-Madjar, A AF van Noort, M Lanz, T Lamers, HJGLM Kurucz, RL Ferlet, R Hebrard, G Vidal-Madjar, A TI Fe II emission lines in the UV spectrum of Sirius-A and Vega SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : atmospheres; stars : chromospheres; stars : Sirius, Vega; line : formation; ultraviolet : stars ID HST-GHRS OBSERVATIONS; ATMOSPHERES; BOUNDARY; STARS AB We present high-quality HST/GHRS spectra in the Hydrogen Let spectral region of Vega and Sirius-A. Thanks to the signal-to-noise ratio achieved in these observations and to the similarity of the two spectra, we found clear evidence of emission features in the low flux region, lambda lambda 1190-1222 Angstrom. These emission lines can be attributed unambiguously to Fe II and Cr II transitions. In this spectral range, silicon lines are observed in absorption. We built a series of non-LTE model atmospheres with different, prescribed temperature stratification in the upper atmosphere and treating Fe II with various degrees of sophistication in non-LTE. Emission lines are produced by the combined effect of the Schuster mechanism and radiative interlocking, and can be explained without the presence of a chromosphere. Silicon absorption lines and the La profile set constraints on the presence of a chromosphere, excluding a strong temperature rise in layers deeper than tau(R) approximate to 10(-4). C1 Univ Utrecht, Sterrekundig Inst, NL-3508 TA Utrecht, Netherlands. SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Inst Astrophys, CNRS, F-75014 Paris, France. RP van Noort, M (reprint author), Univ Utrecht, Sterrekundig Inst, Princetonplein 5, NL-3508 TA Utrecht, Netherlands. EM noort@physics.usyd.edu.au; lanz@fys.ruu.nl; hennyl@sron.ruu.nl; kurucz@cfa.harvard.edu; ferlet@iap.fr; hebrard@iap.fr; vidalmadjar@iap.fr NR 24 TC 8 Z9 8 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 10 PY 1998 VL 334 IS 2 BP 633 EP 645 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZW909 UT WOS:000074460500036 ER PT J AU Huttemeister, S Dahmen, G Mauersberger, R Henkel, C Wilson, TL Martin-Pintado, J AF Huttemeister, S Dahmen, G Mauersberger, R Henkel, C Wilson, TL Martin-Pintado, J TI Molecular gas in the Galactic center region - III. Probing shocks in molecular cores SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : clouds; ISM : molecules; ISM : structure; Galaxy : center; radio lines : ISM ID STAR-FORMING REGIONS; DENSE INTERSTELLAR CLOUDS; CARBON-MONOXIDE; NEARBY GALAXIES; ABUNDANCES; MULTILEVEL; CHEMISTRY; EMISSION; KINEMATICS; EXCITATION AB Multiline observations of (CO)-O-18 and SiO isotopomers toward 33 molecular peaks in the Galactic center region, taken at the SEST, JCMT and HHT telescopes, are presented. The (CO)-O-18 presumably traces the total Hz column density, while the SiO traces gas affected by shocks and high temperature chemistry. The J = 2 --> 1 line of SiO is seen only in few regions of the Galactic disk. This line is easily detected in all Galactic center sources observed. A comparison of the strength of the rare isotopomers (SiO)-Si-29 and (SiO)-Si-30 to the strength of the main isotopomer (SiO)-Si-28 implies that the J = 2 --> 1 transition of (SiO)-Si-28 is optically thick. The Si-29/Si-30 isotope ratio of 1.6 in the Galactic center clouds is consistent with the terrestrial value. Large Velocity Gradient models show that the dense component (n(H2), greater than or equal to 10(4) cm(-3)) in typical molecular cores in the Galactic center is cool (T-kin approximate to 25 K), contrary to what is usually found in Giant Molecular Clouds in the disk, where the densest cores are the hottest. High kinetic temperatures, > 100 K, known to exist from NH3 studies, are only present at lower gas densities of a few 10(3) cm(-3), where SiO is highly subthermally excited. Assuming that (CO)-O-18 traces all of the molecular gas, it is found that in all cases but one, SiO emission is compatible with arising in gas at higher density that is (presently) relatively cool. The relative abundance of SiO is typically 10(-9), but differs significantly between individual sources. It shows a dependence on the position of the source within the Galactic center region. High abundances are found in those regions for which bar potential models predict a high likelihood for cloud-cloud collisions. These results can be used to relate the amount of gas that has encountered shocks within the last similar to 10(6) years to the large scale kinematics in the inner similar to 500 PC Of the Galaxy. C1 Univ Bonn, Inst Radioastron, D-53121 Bonn, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ London Queen Mary & Westfield Coll, Dept Phys, London E1 4NS, England. Max Planck Inst Radioastron, D-53121 Bonn, Germany. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Arizona, Submillimeter Telescope Observ, Tucson, AZ 85721 USA. Ctr Astron Yebes, E-19080 Guadalajara, Spain. RP Huttemeister, S (reprint author), Univ Bonn, Inst Radioastron, Hugel 71, D-53121 Bonn, Germany. RI Martin-Pintado, Jesus/H-6107-2015 OI Martin-Pintado, Jesus/0000-0003-4561-3508 NR 60 TC 60 Z9 60 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 10 PY 1998 VL 334 IS 2 BP 646 EP 658 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZW909 UT WOS:000074460500037 ER PT J AU Donnelly, RA Markevitch, M Forman, W Jones, C David, LP Churazov, E Gilfanov, M AF Donnelly, RA Markevitch, M Forman, W Jones, C David, LP Churazov, E Gilfanov, M TI Temperature structure in Abell 1367 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (A1367); galaxies : interactions; intergalactic medium; methods : numerical; shock waves; X-rays : galaxies ID X-RAY-CLUSTERS; IMAGING OBSERVATIONS; GALAXIES; GAS; EVOLUTION AB We study the temperature structure of the rich cluster of galaxies Abell 1367 using two independent methods of correcting for the ASCA point-spread function. The results of the two methods are in excellent agreement and give solid evidence of a strong and localized shock in the intracluster medium. Our analysis suggests that we are observing the merger of two subclusters. We find that the lower luminosity subcluster, located to the northwest, has a higher temperature of 4.2 +/- 0.3 keV, compared to the more luminous southeast subcluster, whose temperature is 3.2 +/- 0.1 keV. An analysis of the ROSAT surface brightness profiles of both subclusters is also presented. The data agree well with predictions from numerical simulations of mergers between subcluster-sized masses, in particular with early stages of the merger prior to the first core passage. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Moscow Space Res Inst, Moscow 117810, Russia. Max Planck Inst Astrophys, D-85740 Garching, Germany. RP Donnelly, RA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Churazov, Eugene/A-7783-2013 NR 28 TC 57 Z9 57 U1 0 U2 0 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 10 PY 1998 VL 500 IS 1 BP 138 EP 146 DI 10.1086/305719 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZV139 UT WOS:000074273300012 ER PT J AU Johnson, CO De Pree, CG Goss, WM AF Johnson, CO De Pree, CG Goss, WM TI A high-resolution VLA study of M17-UC1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE H II regions; ISM : individual (M17); masers; radio lines : ISM ID H-II REGIONS; RECOMBINATION LINE; STAR-FORMATION; HII-REGIONS; EMISSION; M17 AB Using the Very Large Array, we have observed the H66 alpha radio recombination line (RRL) emission at 1.3 cm and the H52 alpha RRL emission at 7 mm toward the ultracompact H II region M17-UC1 and the nearby are-shaped structure to the east. The angular resolution of the data is 1"-2". The compact H II region (deconvolved size similar to 0".6 or 0.006 pc) is one of a number of H II regions with broad (greater than or equal to 35 km s(-1)) RRLs. The line parameters of the nearby are of ionized emission thereafter the Are), about 1" or 0.01 pc to the east of UC1, are remarkably constant over an area of 16".5 x 3" (0.17 pc x 0.03 pc). The derived LTE electron temperature from the H66 alpha line (T-H66 alpha* is 6600 K in M17-UC1 and 8200 K in the Are region. H2O maser emission at 1.3 cm from the region of M17-UC1 was observed in the D array with a beam of 4". Observations of the H2O maser emission toward M17-UC1 reveal four masers within 30" of M17-UC1; two of these sources were previously known. We discuss the region near M17-UC1 as an example of shock-induced star formation consisting of a hot, young, massive star surrounded by ionized material, perhaps resulting from a stellar wind outflow. We compare M17-UC1 with the six other known examples of broad-line RRL emission from ultracompact H II regions. C1 Vassar Coll, Dept Phys & Astron, Poughkeepsie, NY 12601 USA. Agnes Scott Coll, Dept Phys & Astron, Decatur, GA 30030 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. RP Johnson, CO (reprint author), Harvard Smithsonian Ctr Astrophys, MS 21,60 Garden St, Cambridge, MA 02138 USA. NR 29 TC 29 Z9 29 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1998 VL 500 IS 1 BP 302 EP 310 DI 10.1086/305717 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZV139 UT WOS:000074273300025 ER PT J AU D'Alessio, P Canto, J Calvet, N Lizano, S AF D'Alessio, P Canto, J Calvet, N Lizano, S TI Accretion disks around young objects. I. The detailed vertical structure SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; radiative transfer; stars : pre-main-sequence ID T-TAURI-STARS; LOCAL SHEAR INSTABILITY; WEAKLY MAGNETIZED DISKS; SPECTRAL ENERGY-DISTRIBUTIONS; CIRCUMSTELLAR DISKS; EVOLUTION; MODELS; CLOUDS; SYSTEMS; FIELDS AB We discuss the properties of an accretion disk around a star with parameters typical of classical T Tauri stars (CTTSs) and with the average accretion rate for these disks. The disk is assumed steady and geometrically thin. The turbulent viscosity coefficient is expressed using the a prescription, and the main heating mechanisms considered are viscous dissipation and irradiation by the central star. The energy is transported by radiation, turbulent conduction, and convection. We find that irradiation from the central star is the main heating agent of the disk, except in the innermost regions, R < 2 AU. The irradiation increases the temperature of the outer disk relative to the purely viscous case. As a consequence, the outer disk (R > 5 AU) becomes less dense, optically thin, and almost vertically isothermal, with a temperature distribution T proportional to R-1/2. The decrease in surface density at the outer disk decreases the disk mass by a factor of 4 with respect to a purely viscous case. In addition, irradiation tends to make the outer disk regions stable against gravitational instabilities. C1 Univ Nacl Autonoma Mexico, Inst Astron, Mexico City 04510, DF, Mexico. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP D'Alessio, P (reprint author), Univ Nacl Autonoma Mexico, Inst Astron, AP 70-264, Mexico City 04510, DF, Mexico. NR 59 TC 366 Z9 368 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1998 VL 500 IS 1 BP 411 EP 427 DI 10.1086/305702 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZV139 UT WOS:000074273300035 ER PT J AU Dupree, AK Brickhouse, NS AF Dupree, AK Brickhouse, NS TI ORFEUS observations of luminous cool stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars, atmospheres; stars, late-type; stars, mass loss; ultraviolet, stars ID ULTRAVIOLET AB The ORFEUS telescope obtained far-ultraviolet spectra (lambda lambda 912-1218) of three luminous cool stars: P Draconis (HD 159181) and two hybrid stars, alpha Aquarii (HD 209750) and alpha Trianguli Australis (HD 150798). Most striking is the detection of blueshifted O VI lambda 1032, and C III lambda 977 emission relative to Si III lambda 1206, indicating outward motion, and the markedly narrow resonance line profiles of C III and Si III in the two hybrid objects as compared with the coronal star beta Dra. The observed Doppler shifts suggest that a warm wind of at least 3 x 10(5) K occurs in the hybrid stars with outflows similar to 100-200 km s(-1); narrow lines of C III and Si III are consistent with signatures of wind absorption. The asymmetric profile of C III in P Dra might also result from wind absorption, although the acceleration would have to begin at higher temperatures (T similar to 70,000 K) in this coronal star as compared with the hybrids, since its chromospheric Mg II profiles show no asymmetry due to wind absorption. Electron densities determined from C III multiplets in beta Dra and alpha TrA indicate values between 8.3 and 8.6 dex (cm(-3)), giving a pressure of similar to 2 x 10(13) cm(-3) K, at T similar to 7 x 10(4) K. Wind absorption and interstellar extinction must be considered when applying emission-line diagnostics in this wavelength region. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Dupree, AK (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM dupree@cfa.harvard.edu; nbrickhouse@cfa.harvard.edu NR 18 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1998 VL 500 IS 1 BP L33 EP L36 DI 10.1086/311397 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZV153 UT WOS:000074275000008 ER PT J AU Braun, MJ Brumfield, RT AF Braun, MJ Brumfield, RT TI Enigmatic phylogeny of skuas: an alternative hypothesis SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE Stercorariidae; skua; phylogeny; lineage sorting; mtDNA; avian systematics ID SUBSTITUTION RATES; TREES AB Last year, Cohen et al. presented molecular data suggesting the surprising result that both currently recognized genera of skuas, Stercorarius and Catharacta (Aves: Stercorariidae), are not monophyletic. However, the most enigmatic conclusion from their analysis, that S. pomarinus is sister to C. skua, rests solely on mtDNA sequence data. When the mtDNA data are analysed in a maximum likelihood framework that accounts for variation in evolutionary rates, Catharacta monophyly cannot be rejected. None of the best trees that can be derived from two nuclear data sets of Cohen et al. support the controversial pomarinus-C. skua node. We propose an alternative hypothesis, that pomarinus is sister to a monophyletic Catharacta, as the best explanation of the available molecular, morphological, and behavioural evidence. C1 Natl Museum Nat Hist, Smithsonian Inst, MRC 534, Lab Mol Systemat, Washington, DC 20560 USA. Univ Maryland, Dept Zool, College Pk, MD 20742 USA. RP Braun, MJ (reprint author), Natl Museum Nat Hist, Smithsonian Inst, MRC 534, Lab Mol Systemat, Washington, DC 20560 USA. EM braun@onyx.si.edu RI Brumfield, Robb/K-6108-2015 OI Brumfield, Robb/0000-0003-2307-0688 NR 34 TC 14 Z9 16 U1 0 U2 2 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 JUN 7 PY 1998 VL 265 IS 1400 BP 995 EP 999 PG 5 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA ZU419 UT WOS:000074195200008 ER PT J AU Schlebecker, JT AF Schlebecker, JT TI Sowing modernity: America's first agricultural revolution. SO AGRICULTURAL HISTORY LA English DT Book Review C1 Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CALIF PRESS PI BERKELEY PA JOURNALS DEPT 2120 BERKELEY WAY, BERKELEY, CA 94720 USA SN 0002-1482 J9 AGR HIST JI Agric. Hist. PD SUM PY 1998 VL 72 IS 3 BP 622 EP 623 PG 2 WC Agriculture, Multidisciplinary; History; History & Philosophy Of Science SC Agriculture; History; History & Philosophy of Science GA 128NR UT WOS:000076413300016 ER PT J AU Rasmussen, HN Whigham, DF AF Rasmussen, HN Whigham, DF TI Importance of woody Debris in seed germination of Tipularia discolor (Orchidaceae) SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE decomposing wood; forest ecosystem; germination; mycoheterotrophy; orchid mycorrhiza; seed biology; Tipularia; Orchidaceae ID ECOLOGY AB Concerns about declining populations of terrestrial orchids make it important to identify the environmental factors crucial to seedling recruitment. This study shows that.seedlings of Tipularia discolor (cranefly orchid) primarily occur on decomposing wood. Extensive searches of decomposing logs and stumps in mature and successional forests revealed seedlings at 24 sites, of which 15 could be identified as originating from seven different deciduous trees and one conifer. Seeds were planted in natural habitats to test the hypothesis that germination requires decomposing wood. In one experiment, seeds were placed into soil at sites where adult plants were abundant; no germination resulted. In a second experiment, germination of seeds sown in ambient soil was compared with sowings in plots amended with decomposing wood collected from a stump where spontaneous seedlings grew. Germination was much more frequent in plots amended with decomposing wood. We conclude that germination of T. discolor is stimulated in substrates that contain decomposing wood; judging from the occurrence of spontaneous seedlings, wood from at variety of tree species offer a suitable substrate. C1 Res Ctr Arslev, Dept Ornamentals, DK-5792 Arslev, Denmark. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Whigham, DF (reprint author), Res Ctr Arslev, Dept Ornamentals, Kirstinebjergvej 10, DK-5792 Arslev, Denmark. RI Rasmussen, Hanne/P-5485-2014; OI Rasmussen, Hanne/0000-0002-0181-9304; Whigham, Dennis/0000-0003-1488-820X NR 33 TC 37 Z9 39 U1 1 U2 9 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 JUN PY 1998 VL 85 IS 6 BP 829 EP 834 DI 10.2307/2446418 PG 6 WC Plant Sciences SC Plant Sciences GA ZW469 UT WOS:000074414100011 PM 21684967 ER PT J AU Wen, J Shi, SH Jansen, RK Zimmer, EA AF Wen, J Shi, SH Jansen, RK Zimmer, EA TI Phylogeny and biogeography of Aralia sect. Aralia (Araliaceae) SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE Aralia sect. Aralia; Araliaceae; Asian North American disjunction; biogeography ID EASTERN NORTH-AMERICA; MOLECULAR DIVERGENCE; RIBOSOMAL DNA; HISTORICAL BIOGEOGRAPHY; MAGNOLIA MAGNOLIACEAE; NUCLEOTIDE-SEQUENCES; ASIA; RYTIDOSPERMUM; ASTERACEAE; DISPERSAL AB Aralia sect. Aralia (Araliaceae) consists of approximately eight species disjunctly distributed in Asia and North America. Phylogenetic and biogeographic analyses were conducted using sequences of the internal transcribed spacer regions of the nuclear ribosomal DNA. Aralia racemosa from eastern North America was sister to A. californica from western North America. Aralia cordata from eastern Asia did not form a species-pair relationship with the eastern North American A. racemosa. The two subspecies of A. racemosa formed a monophyletic group. Biogeographic analyses showed a close area relationship between eastern North America and western North America. The Himalayas were cladistically basal and eastern Asia was placed between the Himalayas and North America. The biogeographic analysis supported the origin of the eastern Asian and eastern North American disjunct pattern in Aralia sect. Aralia via the Bering land bridges. Comparisons with results of phylogenetic analyses of other genera suggested that (1) the floristic connection between eastern North America and western North America may be stronger than previously thought; and (2) the biogeographic patterns in the Northern Hemisphere are complex. Furthermore, a lack of correlation between sequence divergence values and phylogenetic positions was observed, suggesting the importance of a phylogenetic framework in biogeographic analyses. C1 Colorado State Univ, Dept Biol, Ft Collins, CO 80523 USA. Zhongshan Univ, Dept Biol, Guangzhou, Peoples R China. Univ Texas, Dept Bot, Austin, TX 78713 USA. Smithsonian Inst, Lab Mol Systemat, Washington, DC 20560 USA. Smithsonian Inst, Dept Bot, Washington, DC 20560 USA. RP Wen, J (reprint author), Colorado State Univ, Dept Biol, Ft Collins, CO 80523 USA. RI Jansen, Robert/F-6272-2011; Zimmer, Elizabeth/G-3890-2011 NR 90 TC 63 Z9 70 U1 2 U2 16 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 JUN PY 1998 VL 85 IS 6 BP 866 EP 875 DI 10.2307/2446422 PG 10 WC Plant Sciences SC Plant Sciences GA ZW469 UT WOS:000074414100015 PM 21684970 ER PT J AU Jennions, MD AF Jennions, MD TI Tibial coloration, fluctuating asymmetry and female choice behaviour in the damselfly Platycypha caligata SO ANIMAL BEHAVIOUR LA English DT Article ID MALE SEXUAL ORNAMENTS; HETAERINA-AMERICANA; MATING SUCCESS; MATE CHOICE; SELECTION; PREFERENCE; CHLOROCYPHIDAE; OVIPOSITION; ODONATA; STRESS AB The territorial damselfly Platycypha caligata (Odontata: Chlorocyphidae) has a courtship behaviour where males wave the white anterior surface of all six laterally enlarged tibiae at females. I experimentally altered this white tibial surface using black paint to determine the effect on male behaviour of a 25% reduction in area, or an increase in asymmetry between the left and right side of the body. I collected behavioural data on courtship, mating and fighting for males already holding territories. Neither a reduction in the area nor an increase in asymmetry of tibial whiteness affected male mating rate, courtship rate or fighting behaviour. These manipulations also had no significant effect on the daily presence at the study site. Males whose tibial whiteness was experimentally removed also showed no decrease in mating rate or change in fighting behaviour while territorial. The complete removal of tibial whiteness did, however, lead to a significant reduction in daily presence, possibly due to a reduced ability to acquire or hold a territory. There was no relationship between natural levels of asymmetry in tibial whiteness and mating rate, courting rate or fighting behaviour for males with territories. However, the natural area of tibial whiteness was significantly positively related to both mean male mating rate and copulation duration for territorial males. This result suggests that a phenotypic correlate of area of tibial whiteness, probably body size, is sexually selected through female choice among males that already hold territories. (C) 1998 The Association for the Study of Animal Behaviour. C1 Univ Witwatersrand, Dept Zool, Witwatersrand, South Africa. Univ Oxford, Dept Zool, Oxford OX1 3PS, England. RP Jennions, MD (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. RI Jennions, Michael/C-7560-2009 OI Jennions, Michael/0000-0001-9221-2788 NR 45 TC 15 Z9 15 U1 2 U2 8 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 JUN PY 1998 VL 55 BP 1517 EP 1528 DI 10.1006/anbe.1997.0656 PN 6 PG 12 WC Behavioral Sciences; Zoology SC Behavioral Sciences; Zoology GA 102QX UT WOS:000074936600012 ER PT J AU Backwell, PRY O'Hara, PD Christy, JH AF Backwell, PRY O'Hara, PD Christy, JH TI Prey availability and selective foraging in shorebirds SO ANIMAL BEHAVIOUR LA English DT Article ID FIDDLER-CRAB; FOOD AVAILABILITY; UCA ANNULIPES; MATE CHOICE; BEHAVIOR; SIZE; PERSPECTIVE; PREDATION; PUGILATOR; COURTSHIP AB Accurate measurements of prey availability are vital to our understanding of foraging behaviour, particularly prey selectivity. In the present study, observations of shorebirds foraging for fiddler crabs on intertidal mudflats demonstrate that prey availability depends both on the temporal variation in crab activity and on the crabs' responses to the presence of foraging shorebirds. Our results suggest that measurements of prey availability that do not specifically account for prey activity patterns and their responses to predators are neccessarily inaccurate. Furthermore, our results also show that tests for foraging selectivity are extremely sensitive to the way in which prey availability is measured and can even indicate active prey selectivity when more accurate measures of prey availability show predators to be non-selective. Because inaccurate measures of food resources greatly reduce our ability to detect food preferences, greater care must be taken to account for prey activity patterns and their responses to predators in measurements of prey availability. (C) 1998 The Association for the Study of Animal Behaviour. C1 Smithsonian Trop Res Inst, Balboa, Panama. Simon Fraser Univ, Dept Biol Sci, Wildlife Ecol Chair Dept Biol Sci, Burnaby, BC V5A 1S6, Canada. RP Backwell, PRY (reprint author), Smithsonian Trop Res Inst, POB 2072, Balboa, Panama. EM backwelp@naos.si.edu RI Backwell, Patricia/C-8883-2009 NR 42 TC 52 Z9 55 U1 0 U2 7 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 JUN PY 1998 VL 55 BP 1659 EP 1667 DI 10.1006/anbe.1997.0713 PN 6 PG 9 WC Behavioral Sciences; Zoology SC Behavioral Sciences; Zoology GA 102QX UT WOS:000074936600024 ER PT J AU Boughman, JW Wilkinson, GS AF Boughman, JW Wilkinson, GS TI Greater spear-nosed bats discriminate group mates by vocalizations SO ANIMAL BEHAVIOUR LA English DT Article ID TADARIDA-BRASILIENSIS-MEXICANA; FREE-TAILED BATS; VOCAL RECOGNITION; UNDERWATER VOCALIZATIONS; INDIVIDUAL RECOGNITION; PHYLLOSTOMUS-DISCOLOR; SOCIAL-ORGANIZATION; CHICKADEE CALLS; VERVET MONKEYS; SONG AB Individuals often benefit from identifying their prospective social partners. Some species that live in stable social groups discriminate between their group mates and others, basing this distinction on calls that differ among individuals. Vocalizations that differ between social groups are much less common, and few studies have demonstrated that animals use group-distinctive calls to identify group mates. Female greater spear-nosed bats, Phyllostomus hastatus, live in stable groups of unrelated bats and give audible frequency, broadband calls termed screech calls when departing from the roost and at foraging sites. Previous field observations suggested that bats give screech calls to coordinate movements among group members. Prior acoustic analyses of 12 acoustic variables found group differences but not individual differences. Here, we use the same acoustic variables to compare calls from three cave colonies, and find that calls differ between caves. We also report results from field and laboratory playback experiments designed to test whether bats use acoustic differences to discriminate calls from different colonies, groups or individuals. Results from field playbacks indicate that response depends on the cave of origin, indicating that bats can discriminate among calls from different caves. This discrimination ability may be based, in part, on;whether calls are familiar or unfamiliar to the listening bats. Laboratory playbacks demonstrate that bats discriminate calls given by their group mates from calls given by other bats from the same cave irrespective of familiarity. However, these experiments provide no evidence that bats discriminate among individuals. Previous field work indicates that females that forage with social group mates map benefit from shared information about food or mutual defence of feeding sites. Indicating group membership is essential? since these benefits appear to be restricted to group mates. (C) 1998 The Association for the Study of Animal Behaviour. C1 Univ Maryland, Dept Zool, College Pk, MD 20742 USA. Smithsonian Inst, Dept Zool Res, Natl Zool Pk, Washington, DC 20560 USA. RP Boughman, JW (reprint author), Univ Maryland, Dept Zool, College Pk, MD 20742 USA. EM boughman@umail.umd.edu RI Wilkinson, Gerald/E-4424-2011 OI Wilkinson, Gerald/0000-0001-7799-8444 NR 82 TC 89 Z9 91 U1 4 U2 30 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 JUN PY 1998 VL 55 BP 1717 EP 1732 DI 10.1006/anbe.1997.0721 PN 6 PG 16 WC Behavioral Sciences; Zoology SC Behavioral Sciences; Zoology GA 102QX UT WOS:000074936600029 ER PT J AU Kleyna, JT Geller, MJ Kenyon, SJ Kurtz, MJ Thorstensen, JR AF Kleyna, JT Geller, MJ Kenyon, SJ Kurtz, MJ Thorstensen, JR TI A V and I CCD mosaic survey of the Ursa Minor dwarf spheroidal galaxy SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies, dwarf; galaxies, individual (Ursa Minor); galaxies, stellar content; local group ID SUBSTRUCTURE; STARS AB We discuss a Johnson-Cousins V- and I-band CCD mosaic survey of the Ursa Minor dwarf spheroidal galaxy (dSph) to V similar to 22. We covered UMi with 27 10'.5 x 10'.5 overlapping CCD frames, each frame consisting of two 300 s exposures in each of V and I. We also observed several regions similar to 3 degrees from UMi to obtain an estimate of contamination by galaxies and Galactic stars. We report the first H-R diagram of an entire dSph. Separation of dwarf stars from foreground stars by color allows a robust estimation of the structural parameters of UMi. We examine earlier evidence of two lumps in the UMi stellar distribution. We detect a statistically significant asymmetry in the stellar distribution of UMi along the major axis. Structure in the stellar distribution of UMi might indicate a tidal origin for UMi's high observed mass-to-light ratio. We demonstrate a technique for obtaining the absolute magnitude of UMi from horizontal-branch star counts compared with M92; this method of luminosity estimation is independent of the distance to UMi. We obtain M-V = -8.87 +/- sigma(Mv), where sigma(Mv) = 0.14 if M92 is a perfect calibrator and sigma(Mv) less than or similar to 0.35 is an upper bound on the error arising from differences in stellar populations. Our value for M-v is consistent with earlier measurements and has a smaller uncertainty. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Dartmouth Coll, Dept Phys & Astron, Wilder Lab 6127, Hanover, NH 03755 USA. RP Kleyna, JT (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI KURTZ, Michael /B-3890-2009; OI Kenyon, Scott/0000-0003-0214-609X; Kurtz, Michael/0000-0002-6949-0090 NR 28 TC 50 Z9 50 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1998 VL 115 IS 6 BP 2359 EP 2368 DI 10.1086/300360 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZT599 UT WOS:000074104000017 ER PT J AU Kenyon, SJ Brown, DI Tout, CA Berlind, P AF Kenyon, SJ Brown, DI Tout, CA Berlind, P TI Optical spectroscopy of embedded young stars in the Taurus-Auriga molecular cloud SO ASTRONOMICAL JOURNAL LA English DT Article DE ISM, jets and outflows; stars, formation; stars, pre-main-sequence ID HERBIG-HARO OBJECTS; MAGNETOCENTRIFUGALLY DRIVEN FLOWS; SPECTRAL ENERGY-DISTRIBUTIONS; LOW-MASS STARS; MAIN-SEQUENCE EVOLUTION; INTERMEDIATE-MASS; LUMINOSITY FUNCTIONS; LITHIUM ABUNDANCES; STELLAR CLUSTERS; FORBIDDEN-LINE AB This paper describes the first optical spectroscopic survey of Class I sources (also known as embedded sources and protostars) in the Taurus-Auriga dark cloud. We detect 10 of the 24 known Class I sources in the cloud at 5500-9000 Angstrom. All detected Class I sources have strong Ha emission; most also have strong [O I] and [S II] emission. These data - together with high-guality optical spectra of T Tauri stars in the Taurus-Auriga cloud - demonstrate that forbidden emission lines are stronger and more common in Class I sources than in T Tauri stars. Our results also provide a clear discriminant in the frequency of forbidden line emission between weak-emission and classical T Tauri stars. In addition to strong emission lines, three Class I sources have prominent TiO absorption bands. The M-type central stars of these sources mingle with optically visible T Tauri stars in the H-R diagram and lie somewhat below both the birth line for spherical accretion and the deuterium burning sequence for disk accretion. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Whipple Observ, Amado, AZ 85645 USA. RP Kenyon, SJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Kenyon, Scott/0000-0003-0214-609X NR 79 TC 92 Z9 92 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1998 VL 115 IS 6 BP 2491 EP 2503 DI 10.1086/300368 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZT599 UT WOS:000074104000028 ER PT J AU Mohanty, G Biller, S Carter-Lewis, DA Fegan, DJ Hillas, AM Lamb, RC Weekes, TC West, M Zweerink, J AF Mohanty, G Biller, S Carter-Lewis, DA Fegan, DJ Hillas, AM Lamb, RC Weekes, TC West, M Zweerink, J TI Measurement of TeV gamma-ray spectra with the Cherenkov imaging technique SO ASTROPARTICLE PHYSICS LA English DT Article DE gamma rays; general stars; individual (Crab Nebula) ID CRAB-NEBULA; ENERGIES AB In this paper, we seek to establish reliable methods for extracting energy spectra for TeV gamma-ray sources observed using the atmospheric Cherenkov Imaging Technique, Careful attention has been paid to the calculation of the telescope gain, and we obtain good agreement between direct measurements, with a statistical error of about 10%, and an absolute calibration from the background cosmic-ray trigger rate that has an overall error of 18%. Two independent analyses that are based on different Monte Carlo shower simulations, employ different selection criteria in order to retain a large fraction of gamma-ray events, and use different approaches to spectral estimation are presented here. The first is a fairly traditional method that builds on established image selection techniques and calculates the detector collection area and an energy estimation function. The error in measuring the enrgy of a single event is estimated at 36%, and we try to compensate for this poor energy resolution. The second analysis uses more elegant gamma-ray selection criteria and implicitly incorporates the properties of the detector into the simulations that are then compared with the data in order to obtain source spectra. The two simulations are compared to each other and to the data, with the aim of establishing that each method is robust and insensitive to simulation details. Finally, we consider the main sources of systematic errors, the largest of which is in the telescope gain calibration, arising from an incomplete knowledge of the relevant factors, and is estimated to be 16%. The effect of possible errors in the simulations is also considered. Both methods have been applied to a part of the Whipple observatory database on the Crab Nebula for the 1988/89 observing season, while the first method has also been applied to data taken in 1995/96. The statistical error in the flux constant is about 8% and that in the spectral index is about 5%, while the corresponding systematic errors are estimated to be 18% and 2%, respectively. The results presented here show good agreement between the two methods as well as between the two seasons. However, a comprehensive consideration of the implications of the derived spectra and a comparison to other work is addressed in another paper. (C) 1998 Elsevier Science B.V. C1 Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. Natl Univ Ireland Univ Coll Dublin, Dept Phys, Dublin 4, Ireland. Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. RP Mohanty, G (reprint author), Ecole Polytech, LPNHE, F-91128 Palaiseau, France. NR 37 TC 84 Z9 84 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 J9 ASTROPART PHYS JI Astropart Phys. PD JUN PY 1998 VL 9 IS 1 BP 15 EP 43 DI 10.1016/S0927-6505(98)00005-X PG 29 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 103EQ UT WOS:000075145600002 ER PT J AU Bergin, EA Melnick, GJ Neufeld, DA AF Bergin, EA Melnick, GJ Neufeld, DA TI The postshock chemical lifetimes of outflow tracers and a possible new mechanism to produce water ice mantles SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, abundances; ISM, clouds; ISM, molecules; molecular processes shock waves ID DENSE INTERSTELLAR CLOUDS; YOUNG STELLAR OBJECTS; OB1 MOLECULAR CLOUD; STAR FORMATION; LINE EMISSION; SHOCK-WAVES; GAS; CHEMISTRY; REGION; OXYGEN AB We have used a coupled time-dependent chemical and dynamical model to investigate the lifetime of the chemical legacy in the wake of C-type shocks. We concentrate this study on the chemistry of H2O and O-2, two molecules which are predicted to have abundances that are significantly affected in shock-heated gas. Two models are presented: (1) a three-stage model of preshock, shocked, and postshock gas; and (2) a Monte Carlo cloud simulation where we explore the effects of stochastic shock activity on molecular gas over a cloud lifetime. For both models we separately examine the pure gas-phase chemistry as well as the chemistry including the interactions of molecules with grain surfaces. In agreement with previous studies, we find that shock velocities in excess of 10 km s(-1) are required to convert all of the oxygen not locked in CO into H2O before the gas has an opportunity to cool. For pure gasphase models the lifetime of the high water abundances, or "H2O legacy," in the postshock gas is similar to(4-7) x 10(5) yr, independent of the gas density. A density dependence for the lifetime of H2O is found in gas-grain models as the water molecules deplete onto grains at the depletion timescale. Through the Monte Carlo cloud simulation we demonstrate that the time-average abundance of H2O, the weighted average of the amount of time gas spends in preshock, shock, and postshock stages, is a sensitive function of the frequency of shocks. Thus we predict that the abundance of H2O, and to a lesser extent O-2, can be used to trace the history of shock activity in molecular gas. We use previous large-scale surveys of molecular outflows to constrain the frequency of 10 km s(-1) shocks in regions with varying star formation properties and discuss the observations required to test these results. We discuss the postshock lifetimes for other possible outflow tracers (e.g., SiO and CH3OH) and show that the differences between the lifetimes for various tracers can produce potentially observable chemical variations between younger and older outflows. For gas-grain models we find that the abundance of water-ice on grain surfaces can be quite large and is comparable to that observed in molecular clouds. This offers a possible alternative method to create water mantles without resorting to grain surface chemistry: gas heating and chemical modification due to a C-type shock and subsequent depletion of the gas-phase species onto grain mantles. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Harvard Smithsonian Ctr Astrophys, MS-66,60 Garden St, Cambridge, MA 02138 USA. EM ebergin@cfa.harvard.edu; gmelnick@cfa.harvard.edu; neufeld@pha.jhu.edu NR 77 TC 147 Z9 147 U1 0 U2 0 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 1 PY 1998 VL 499 IS 2 BP 777 EP 792 DI 10.1086/305656 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU199 UT WOS:000074172200024 ER PT J AU Jonker, PG Wijnands, R van der Klis, M Psaltis, D Kuulkers, E Lamb, FK AF Jonker, PG Wijnands, R van der Klis, M Psaltis, D Kuulkers, E Lamb, FK TI Discovery of kilohertz quasi-periodic oscillations in the Z source GX 340+0 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars, individual (GX 340+0); stars, neutron; X-rays, stars ID TIMING BEHAVIOR; GX-340+0 AB We have discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the Z source GX 340+0 with the Rossi X-Ray Timing Explorer. The X-ray hardness-intensity and color-color diagrams each show a full Z track, with an extra limb branching off the Paring branch of the Z. Both peaks moved to higher frequencies when the mass accretion rate increased. The two peaks moved from 247 +/- 6 and 567 +/- 39 Hz at the left end of the horizontal branch to 625 +/-: 18 and 820 +/- 19 Hz at its right end. The higher frequency peak's rms amplitude (5-60 keV) and FWHM decreased from similar to 5% and 383 +/- 135 Hz to similar to 2% and 145 +/- 62 Hz, respectively. The rms amplitude and FWHM of the lower peak were consistent with being constant near 2.5% and 100 Hz. The kHz QPO separation was consistent with being constant at 325 +/- 10 Hz. Simultaneous with the kHz QPOs, we detected the horizontal-branch oscillation (HBO) and its second harmonic, at frequencies between 20 and 50 Hz, and 38 and 69 Hz, respectively. The normal-branch oscillations were only detected on the upper and middle normal branch and became undetectable on the lower normal branch. The HBO frequencies do not fall within the range predicted for Lense-Thirring precession, unless either the ratio of the neutron star moment of inertia to neutron star mass is at least 4, 10(45) cm(2) M-.(-1) the frequencies of the HBOs are in fact the second harmonic oscillations, or the observed kHz peak difference Is half the spin frequency and not the spin frequency. During a 1.2 day gap between two observations, the Z track in the hardness-intensity diagram moved to higher count rates by about 3.5%. Comparing data before and after this shift, we find that the HBO properties are determined by position on the Z track and not directly by count rate or X-ray colors. C1 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. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Oxford, Nucl & Astrophys Lab, Oxford OX1 3RH, England. Univ Illinois, Dept Phys & Astron, Urbana, IL 61801 USA. RP Jonker, PG (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. NR 24 TC 41 Z9 41 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1998 VL 499 IS 2 BP L191 EP L194 DI 10.1086/311372 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU234 UT WOS:000074175800018 ER PT J AU Loeb, A AF Loeb, A TI Direct measurement of cosmological parameters from the cosmic deceleration of extragalactic objects SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology, theory AB The redshift of all cosmological sources drifts by a systematic velocity of order a few meters per second over a century as a result of the deceleration of the universe. The specific functional dependence of the predicted velocity shift on the source redshift can be used to verify its cosmic origin and to measure directly the values of cosmological parameters, such as the density parameters of matter and vacuum, Omega(M), and Omega(Lambda), and the Hubble constant H-0. For example, an existing spectroscopic technique, which was recently employed in planet searches, is capable of uncovering velocity shifts of this magnitude. The cosmic deceleration signal might be marginally detectable through two observations of similar to 10(2) quasars set a decade apart, with the HIRES instrument on the Keck 10 m telescope. The signal would appear as a global redshift change in the Ly alpha forest templates imprinted on the quasar spectra by the intergalactic medium. The deceleration amplitude should be isotropic across the sky. Contamination of the cosmic signal by peculiar accelerations or local effects is likely to be negligible. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Loeb, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 16 TC 123 Z9 124 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1998 VL 499 IS 2 BP L111 EP L114 DI 10.1086/311375 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU234 UT WOS:000074175800001 ER PT J AU Stauffer, JR Schultz, G Kirkpatrick, JD AF Stauffer, JR Schultz, G Kirkpatrick, JD TI Keck spectra of pleiades brown dwarf candidates and a precise determination of the lithium depletion edge in the Pleiades SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars, low mass, brown dwarfs; open clusters and associations, individual (Pleiades) ID AGE MAIN-SEQUENCE; OPEN CLUSTERS; SEARCH; STARS AB We have obtained intermediate resolution spectra of 11 candidate brown dwarf members of the Pleiades open cluster using the Keck II telescope and Low-Resolution Imaging Spectrograph. Our primary goal was to determine the location of the "lithium depletion edge" in the Pleiades and hence to derive a precise age for the cluster. All but one of our 11 program objects have radial velocities appropriate for Pleiades members, have moderately strong H alpha emission, and have spectral types M6-M8.5 as expected from their (R-I)(c) colors. We have constructed a color-magnitude diagram for the faint end of the Pleiades main sequence, including only stars for which high signal-to-noise spectra in the region of the lithium 6708 Angstrom absorption line have been obtained. These data allow us to accurately determine the Pleiades single-star lithium depletion edge at I-CO = 17.80, (R-I)(CO) = 2.20, spectral type M6.5. By reference to theoretical evolutionary models, this converts fairly directly into an age for the Pleiades of tau = 125 Myr. This is significantly older than the age that is normally quoted, but does agree with some other recent estimates. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Calif Los Angeles, Dept Phys & Astron, Div Astron & Astrophys, Los Angeles, CA 90095 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. NR 34 TC 172 Z9 172 U1 0 U2 0 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 1 PY 1998 VL 499 IS 2 BP L199 EP L203 DI 10.1086/311379 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU234 UT WOS:000074175800020 ER PT J AU Zhao, JH Goss, WM AF Zhao, JH Goss, WM TI Radio continuum structure of IRS 13 and proper motions of compact H II components at the Galactic center SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrometry; Galaxy, center; H II regions; radio continuum, stars; waves AB A compact H Ir region, IRS 13, is located 3 " to the SW of Sgr A*, the compact radio source at the Galactic center. The source is double, IRS 13E and 13W, at 7 and 13 mm as observed with resolutions of 0." 06. A rising spectrum with spectral index of alpha = 0.9 is observed for IRS 13E probably arising from a high-density, ionized stellar wind. IRS 13W has a flat spectrum; in addition, the radio morphology suggests that the emitting material in IRS 13W has been swept off from the stellar envelope associated with IRS 13E by a strong wind and/or an outflow emanating from the IRS 16 complex and/or Sgr A*. Based on two epoch observations between 1991 and 1996, IRS 13E shows no significant proper motion less than 4 mas yr(-1) (3 sigma), while IRS 13W shows a proper motion mu 3(alpha) = 0.4 +/- 0.7, mu(delta), = 6.2 +/- 1.1 mas yr(-1), with respect to Sgr A*. In addition, proper motions of 57 compact H II components at the Galactic center are determined. The proper motion observations suggest that the minicavity is expanding with a speed of 200 km s(-1). The mean transverse velocity of 700 km s(-1) is inferred for the IRS 9 complex, which is located at the SW rim of the eastern cavity. Large proper motions (up to 30 mas yr(-1), or similar to 1200 km s(-1)) are found for a number of H II components associated with filamentary structures, such as the Bullet and the Loop. The large proper motion measured from the compact H II components can be explained by motions of clumpy H II gas accelerated by either strong winds and outflows or explosive events at the Galactic center. Large pattern speeds due to wave motions in the circumnuclear medium at the Galactic center can also be responsible for some components of the observed proper motions. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Radio Astron Observ, AOC, Socorro, NM 87801 USA. RP Zhao, JH (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 17 TC 32 Z9 32 U1 0 U2 0 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 1 PY 1998 VL 499 IS 2 BP L163 EP + DI 10.1086/311374 PN 2 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU234 UT WOS:000074175800012 ER PT J AU Robertson, DR Kaufmann, KC AF Robertson, DR Kaufmann, KC TI Assessing early recruitment dynamics and its demographic consequences among tropical reef fishes: Accommodating variation in recruitment seasonality and longevity SO AUSTRALIAN JOURNAL OF ECOLOGY LA English DT Article; Proceedings Paper CT Joint United-States/Australia Workshop on Recruitment and Population Dynamics of Coral-Reef Fishes (Reefish 95) CY DEC 11, 1995 CL KURANDA, AUSTRALIA SP Australian Dept Ind, Sci & Tourisms Bilateral Sci & Technol Collaborat Program, USA Natl Sci Fdn Int Programs DE coral reefs; fish; Great Barrier Reef; longevity; recruitment; seasonality; tropical northwest Atlantic ID GREAT-BARRIER-REEF; LEE-STOCKING ISLAND; CORAL-REEF; JUVENILE MORTALITY; NURSERY HABITATS; VIRGIN-ISLANDS; PATTERNS; SETTLEMENT; POPULATIONS; GROWTH AB When settlement of pelagic juveniles of reef fishes is highly and predictably seasonal, annual, end-of-season surveys of surviving recruits (which are commonly used on the Great Barrier Reef) are useful for assessing recruitment dynamics and their demographic effects. However, when settlement is continuous or weakly seasonal, with patterns that vary both between species and within species among years, regular, sometimes year-round, recruitment surveys at intervals linked to short-term settlement dynamics are needed to quantify fluctuations in recruitment strength. Monthly recruitment surveys may be appropriate in the tropical northwest Atlantic, where settlement is often both lunar periodic, and broadly and variably seasonal. Use of a variety of recruit-census methods impedes comparisons of recruitment patterns and their demographic effects, because recruit densities and recruit:adult ratios cannot be directly compared when recruits (because they have widely varying post-settlement ages) have experienced very different levels of early post-settlement mortality. Examining the relationship between changes in adult populations and annual, end-of-season recruitment may be satisfactory for long-lived species with strong settlement seasonality and maturation times of approximately 1 year. However, it is inappropriate for short-lived, rapidly maturing species, particularly those that have broad and variable settlement seasons and whose populations fluctuate substantially throughout the year in response to short-term fluctuations in recruitment. Comparisons of demographic effects of recruitment among species with different longevity require the use of non-arbitrary time scales, such as the time to maturity and the adult half-life. C1 Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. RP Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 52 TC 26 Z9 26 U1 0 U2 6 PU BLACKWELL PUBLISHING ASIA PI CARLTON PA 54 UNIVERSITY ST, P O BOX 378, CARLTON, VICTORIA 3053, AUSTRALIA SN 0307-692X J9 AUST J ECOL JI Aust. J. Ecol. PD JUN PY 1998 VL 23 IS 3 BP 226 EP 233 DI 10.1111/j.1442-9993.1998.tb00724.x PG 8 WC Ecology SC Environmental Sciences & Ecology GA ZU238 UT WOS:000074176200006 ER PT J AU Robertson, DR AF Robertson, DR TI Implications of body size for interspecific interactions and assemblage organization among coral-reef fishes SO AUSTRALIAN JOURNAL OF ECOLOGY LA English DT Article; Proceedings Paper CT Joint United-States/Australia Workshop on Recruitment and Population Dynamics of Coral-Reef Fishes (Reefish 95) CY DEC 11, 1995 CL KURANDA, AUSTRALIA SP Australian Dept Ind, Sci & Tourisms Bilateral Sci & Technol Collaborat Program, USA Natl Sci Fdn Int Programs DE assemblage structure; biomass; competition; coral reefs; fish; numeric abundance; population size-structure ID GREAT-BARRIER-REEF; FEEDING TERRITORY SIZE; ONE TREE REEF; CHAETODONTID FISHES; HABITAT USE; DAMSELFISH; PATTERNS; BUTTERFLYFISHES; DETERMINANTS; COMMUNITIES AB Population size-structure is often ignored in assemblage-level studies of reef fishes, which usually rely on static and dynamic patterns of relative total abundance to infer what mechanisms organize those assemblages. However, body size has substantial effects on processes that affect competitive relationships between species: (i) small, recently recruited fish, which usually(?) suffer high mortality, can dominate total abundance and strongly influence the dynamics of the relative total abundances of different species, while having little effect on interspecific biomass relations; (ii) numeric abundance and biomass of a species can vary independently, due to habitat variation in population size-structure resulting from variation in mortality and growth, as well as habitat selection; and (iii) population size-structure affects the potential for and outcome of interspecific competition due to (a) ontogenetic change in types of resources used, (b) levels of resource needs being dependent on individual and species biomass rather than numbers, (c) advantages due to large size in behavioural contests, (d) variation in population size-structure being linked to habitat preference, which affects expression of competitive dominance, and (e) size dependency in the development of interspecific resource-sharing relationships. Assemblage-level analyses that ignore such size effects may fail to detect important effects of interspecific interactions. C1 Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. RP Robertson, DR (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 49 TC 30 Z9 31 U1 1 U2 10 PU BLACKWELL SCIENCE PI CARLTON PA 54 UNIVERSITY ST, P O BOX 378, CARLTON, VICTORIA 3053, AUSTRALIA SN 0307-692X J9 AUST J ECOL JI Aust. J. Ecol. PD JUN PY 1998 VL 23 IS 3 BP 252 EP 257 DI 10.1111/j.1442-9993.1998.tb00728.x PG 6 WC Ecology SC Environmental Sciences & Ecology GA ZU238 UT WOS:000074176200010 ER PT J AU Thies, W Kalko, EKV Schnitzler, HU AF Thies, W Kalko, EKV Schnitzler, HU TI The roles of echolocation and olfaction in two Neotropical fruit-eating bats, Carollia perspicillata and C-castanea, feeding on Piper SO BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY LA English DT Article DE bats; phyllostomidae; echolocation; foraging behavior ID MACROTUS-CALIFORNICUS CHIROPTERA; PREY DETECTION; TRACHOPS-CIRRHOSUS; INSECTIVOROUS BAT; PIPISTRELLE BATS; EPTESICUS-FUSCUS; SENSORY BASIS; DISCRIMINATION; PHYLLOSTOMATIDAE; BEHAVIOR AB We studied the echolocation and foraging behavior of two Neotropical frugivorous leaf-nosed bats (Carollia perspicillata, C. castanea: Phyllostomidae) in a flight cage. To test which cues Carollia uses to detect, identify, and localize ripe Piper fruit, their preferred natural food, we conducted experiments under seminatural conditions with ripe, unripe, and artifical fruits. We first offered the bats ripe fruits and documented their foraging behavior using multiflash stereophotography combined with simultaneous sound recordings. Both species showed a similar, stereotyped foraging pattern. In search flight, the bats circled through the flight cage in search of a branch with ripe fruit. After finding such a branch, the bats switched to approach behavior, consisting of multiple exploration flights and the final approach when the bats picked up the fruit at its tip and tore it off in flight. Our behavioral experiments revealed that odor plays an important role in enabling Carollia to find ripe fruit. While foraging, Carollia always echolocated and produced multiharmonic, frequency-modulated (FM) signals of broad bandwidth, high frequency, short duration, and low intensity. We discriminated an orientation phase (mostly a single pulse per wingbeat) and an approach phase (groups of two to six pulses per wing beat). We conclude from the bats' behavioral reaction to real and artificial fruit as well as from characteristic patterns in their echolocation behavior that during exploration flights, Carollia changes from primarily odor-oriented detection and initial localization of ripe fruit to a primarily echo-oriented final localization of the position of the fruit. C1 Univ Tubingen, D-72076 Tubingen, Germany. Smithsonian Trop Res Inst, Balboa, Panama. Natl Museum Nat Hist, MRC 108, Washington, DC 20560 USA. RP Thies, W (reprint author), Univ Tubingen, Morgenstelle 28, D-72076 Tubingen, Germany. EM Wibke.Thies@uni-tuebingen.de NR 53 TC 110 Z9 112 U1 4 U2 25 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-5443 J9 BEHAV ECOL SOCIOBIOL JI Behav. Ecol. Sociobiol. PD JUN PY 1998 VL 42 IS 6 BP 397 EP 409 DI 10.1007/s002650050454 PG 13 WC Behavioral Sciences; Ecology; Zoology SC Behavioral Sciences; Environmental Sciences & Ecology; Zoology GA ZW167 UT WOS:000074382300003 ER PT J AU Wheeler, JW Lay, DM Blum, MS Weldon, PJ AF Wheeler, JW Lay, DM Blum, MS Weldon, PJ TI Ketones in the anal sac secretions of the masked palm civet, Paguma larvata (Viverridae, Mammalia) SO BIOCHEMICAL SYSTEMATICS AND ECOLOGY LA English DT Article DE Paguma larvata; masked palm civet; anal sacs; ketones C1 Howard Univ, Dept Chem, Washington, DC 20059 USA. Univ N Carolina, Sch Med, Dept Anat, Chapel Hill, NC 27599 USA. Univ Georgia, Dept Entomol, Athens, GA 30602 USA. Smithsonian Inst, Conservat & Res Ctr, Front Royal, VA 22630 USA. RP Wheeler, JW (reprint author), Howard Univ, Dept Chem, Washington, DC 20059 USA. NR 6 TC 1 Z9 2 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0305-1978 J9 BIOCHEM SYST ECOL JI Biochem. Syst. Ecol. PD JUN PY 1998 VL 26 IS 4 BP 457 EP 458 DI 10.1016/S0305-1978(98)80001-X PG 2 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA ZW445 UT WOS:000074411700008 ER PT J AU Pandolfi, JM Robertson, DR Kirtley, DW AF Pandolfi, JM Robertson, DR Kirtley, DW TI Roles of worms in reef-building SO CORAL REEFS LA English DT Article C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Pandolfi, JM (reprint author), STRI, Unit 0948, APO, AA 34002 USA. RI Pandolfi, John/A-3121-2009 OI Pandolfi, John/0000-0003-3047-6694 NR 3 TC 9 Z9 9 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD JUN PY 1998 VL 17 IS 2 BP 120 EP 120 DI 10.1007/s003380050105 PG 1 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 101UL UT WOS:000074886500003 ER PT J AU Littler, MM Littler, DS AF Littler, MM Littler, DS TI An undescribed fungal pathogen of reef-forming crustose coralline algae discovered in American Samoa SO CORAL REEFS LA English DT Article C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Bot, Washington, DC 20560 USA. Harbor Branch Oceanog Inst Inc, Div Marine Sci, Ft Pierce, FL 34946 USA. RP Littler, MM (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Bot, Washington, DC 20560 USA. NR 2 TC 13 Z9 14 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD JUN PY 1998 VL 17 IS 2 BP 144 EP 144 DI 10.1007/s003380050108 PG 1 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 101UL UT WOS:000074886500006 ER PT J AU Robertson, DR AF Robertson, DR TI Do coral-reef fish faunas have a distinctive taxonomic structure? SO CORAL REEFS LA English DT Article DE reef fish; assemblage structure; fossil assemblage ID TROPICAL EASTERN PACIFIC AB Do the highly diverse fish faunas that associate with coral reefs have distinguishing taxonomic and ecological characteristics, as proposed by Cheat and Bellwood (1991) and Bellwood (1996)? Does a 50 my old (Eocene) fossil fish fauna from Italy represent a coral-reef fish assemblage that provides unique information about the evolution of such assemblages, as claimed by Bellwood (1996)? I compared the structure of the reef fish faunas of adjacent tropical regions rich and poor in coral reefs, in both America and Polynesia, and found that they exhibit no substantive differences in relative species richness among families of typical "coral-reef" fishes. While coral-rich regions have larger reef fish faunas, a variety of factors probably contribute to such differences. Thus coral-reef fish faunas may lack a distinctive taxonomic structure. A similar comparative approach would be useful for assessing whether assemblages of fishes on coral reefs have distinctive ecological characteristics. Based on patterns of habitat use by modern tropical shorefishes, the Italian Eocene fauna includes few definite reef fishes, and may well consist primarily of non-reef fishes preserved in a non-reef habitat. Until we know more about the environment in which those fossils were preserved, that fauna can contribute little to understanding how coral reef fish assemblages have evolved. C1 Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. RP Robertson, DR (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 34 TC 31 Z9 36 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD JUN PY 1998 VL 17 IS 2 BP 179 EP 186 DI 10.1007/s003380050113 PG 8 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 101UL UT WOS:000074886500011 ER PT J AU Jackson, JBC AF Jackson, JBC TI Reply to J.L. Munro (Coral Reefs 17 : 191-192) SO CORAL REEFS LA English DT Editorial Material ID DYNAMICS; SCALE C1 Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archeol, Balboa, Panama. RP Jackson, JBC (reprint author), Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archeol, Apartado 2072, Balboa, Panama. NR 18 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD JUN PY 1998 VL 17 IS 2 BP 193 EP 194 DI 10.1007/s003380050117 PG 2 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 101UL UT WOS:000074886500015 ER PT J AU Slikas, B AF Slikas, B TI Recognizing and testing homology of courtship displays in storks (Aves : Ciconiiformes : Ciconiidae) SO EVOLUTION LA English DT Article DE avian behavior; behavioral evolution; congruence; DNA-DNA hybridization; phylogeny ID PHYLOGENETIC ANALYSIS; BEHAVIOR; HOMOPLASY; SEQUENCES; BIOLOGY; WORLD AB Ethological studies in the 1940s and 1950s, most notably those of Lorenz and Tinbergen, emphasized a historical perspective. By the 1970s, the notion that behavioral traits are too plastic to retain historical information became prevalent, and evolutionary approaches in behavioral studies were largely abandoned. However, several recent studies have demonstrated that behavioral characters are remarkably consistent with phylogenies obtained from other data and not particularly prone to homoplasy. In this study, I coded descriptions of courtship display behaviors in stork species (Aves: Ciconiiformes: Ciconiidae) as a matrix of discrete characters. I mapped each behavioral character onto a phylogeny based on DNA-DNA hybridization distances to test the homology of individual characters. Generally, displays occurring early in courtship were congruent with phylogenetic relationships and showed little homoplasy, while displays occurring late in courtship were more homoplastic. I also performed a phylogenetic analysis of the behavioral data matrix using maximum parsimony. The strict consensus of the 24 most-parsimonious trees was congruent with the DNA-DNA hybridization tree in all nodes having greater than 70% bootstrap support. C1 Univ Penn, Dept Biol, Philadelphia, PA 19104 USA. Acad Nat Sci Philadelphia, Philadelphia, PA 19103 USA. RP Slikas, B (reprint author), Smithsonian Inst, Natl Zool Pk, Mol Genet Lab, 3001 Connecticut Ave NW, Washington, DC 20008 USA. RI Slikas, Beth/E-7275-2013 NR 51 TC 33 Z9 34 U1 0 U2 9 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 1998 VL 52 IS 3 BP 884 EP 893 DI 10.2307/2411283 PG 10 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA ZY435 UT WOS:000074621000024 ER PT J AU Lacy, RC Ballou, JD AF Lacy, RC Ballou, JD TI Effectiveness of selection in reducing the genetic load in populations of Peromyscus polionotus during generations of inbreeding SO EVOLUTION LA English DT Article DE genetic load; inbreeding depression; Peromyscus polionotus; population bottlenecks ID DROSOPHILA-MELANOGASTER; SELF-FERTILIZATION; FITNESS COMPONENTS; DEPRESSION; EXTINCTION; VIABILITY; EVOLUTION; BEHAVIOR; ABILITY; MODELS AB It has been hypothesized that natural selection reduces the "genetic load" of deleterious alleles from populations that inbreed during bottlenecks, thereby ameliorating impacts of future inbreeding. We tested the efficiency with which natural selection purges deleterious alleles from three subspecies of Peromyscus polionotus during 10 generations of laboratory inbreeding by monitoring pairing success, litter size, viability, and growth in 3604 litters produced from 3058 pairs. In P. p. subgriseus, there was no reduction across generations in inbreeding depression in any of the fitness components. Strongly deleterious recessive alleles may have been removed previously during episodes of local inbreeding in the wild, and the residual genetic load in this population was not further reduced by selection in the lab. In P. p. rhoadsi, four of seven fitness components did show a reduction of the genetic load with continued inbreeding. The average reduction in the genetic load was as expected if inbreeding depression in this population is caused by highly deleterious recessive alleles that are efficiently removed by selection. For P. p. leucocephalus, a population that experiences periodic bottlenecks in the wild, the effect of further inbreeding in the laboratory was to exacerbate rather than reduce the genetic load. Recessive deleterious alleles may have been removed from this population during repeated bottlenecks in the wild; the population may be close to a threshold level of heterozygosity below which fitness declines rapidly. Thus, the effects of selection on inbreeding depression varied substantially among populations, perhaps due to different histories of inbreeding and selection. C1 Chicago Zool Soc, Daniel F & Ada L Rice Ctr, Dept Conservat Biol, Brookfield, IL 60513 USA. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Lacy, RC (reprint author), Chicago Zool Soc, Daniel F & Ada L Rice Ctr, Dept Conservat Biol, Brookfield, IL 60513 USA. EM rlacy@ix.netcom.com NR 66 TC 82 Z9 82 U1 0 U2 11 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 JUN PY 1998 VL 52 IS 3 BP 900 EP 909 DI 10.2307/2411285 PG 10 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA ZY435 UT WOS:000074621000026 ER PT J AU Kalko, EKV Condon, MA AF Kalko, EKV Condon, MA TI Echolocation, olfaction and fruit display: how bats find fruit of flagellichorous cucurbits SO FUNCTIONAL ECOLOGY LA English DT Article DE dispersal syndrome; frugivore; Gurania spinulosa; Phyllostomidae; Phyllostomus hastatus ID CHIROPTERA; DISPERSAL; EVOLUTION; SIGNALS; FOREST; PLANTS; VINES AB 1. The relationship between plant morphology and the senses used by dispersal agents to find fruit was examined. 'Flagellichory' (fruit borne on pendulous structures), a costly morphology associated with dispersal by bats, is focused on, 2, Using Gurania spinulosa, a flagellichorous vine, and its major dispersal agent, Phyllostomus hastatus, the hypothesis was tested that flagellichory increases the conspicuousness of fruit to bats that use echolocation to find fruit. 3. The responses of wild-caught P. hastatus to various fruiting branch morphologies and fruit odour were recorded. Phyllostomus hastatus used echolocation rather than olfaction to detect fruit, and consistently chose fruit displayed on pendulous leafless branches, ignoring fruit held among leaves on horizontal branches. s4. By comparing echolocation signals with the distance between fruiting branches of G, spinulosa and surrounding vegetation, it was shown that pendulous fruiting branches present clear, clutter-free targets that can be detected by echolocating bats. This is the first demonstration of neotropical frugivorous bats using echolocation to find fruit. C1 Univ Tubingen, D-72076 Tubingen, Germany. Smithsonian Trop Res Inst, Balboa, Panama. Cornell Coll, Dept Biol, Mt Vernon, IA 52314 USA. RP Kalko, EKV (reprint author), Univ Tubingen, Morgenstelle 28, D-72076 Tubingen, Germany. NR 30 TC 72 Z9 75 U1 1 U2 8 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 1998 VL 12 IS 3 BP 364 EP 372 DI 10.1046/j.1365-2435.1998.00198.x PG 9 WC Ecology SC Environmental Sciences & Ecology GA ZZ758 UT WOS:000074764200006 ER PT J AU Tuxill, J Bright, C AF Tuxill, J Bright, C TI Protecting nature's diversity: Mending strands in the web of life SO FUTURIST LA English DT Article C1 Smithsonian Trop Res Inst, Balboa, Panama. Worldwatch Inst, Washington, DC 20036 USA. RP Tuxill, J (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 0 TC 0 Z9 0 U1 0 U2 0 PU WORLD FUTURE SOCIETY PI BETHESDA PA 7910 WOODMONT AVE, SUITE 450, BETHESDA, MD 20814 USA SN 0016-3317 J9 FUTURIST JI Futurist PD JUN-JUL PY 1998 VL 32 IS 5 BP 46 EP 51 PG 6 WC Social Issues SC Social Issues GA ZN600 UT WOS:000073662100029 ER PT J AU Woo, R Habbal, SR AF Woo, R Habbal, SR TI Comment on: "Polar plumes and fine-scale coronal structures - On the interpretation of coronal radio sounding data" by Patzold and Bird SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02178 USA. RP Woo, R (reprint author), CALTECH, Jet Prop Lab, MS 238-725,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 2 Z9 2 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 1849 EP 1850 DI 10.1029/98GL00842 PG 2 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800023 ER PT J AU Marcellini, DL Murphy, JB AF Marcellini, DL Murphy, JB TI Education in a zoological park or aquarium: An ontogeny of learning opportunities SO HERPETOLOGICA LA English DT Article DE herpetology; teaching; learning; audience ID ZOO AB Zoo and aquarium herpetologists can provide an ontogeny of learning opportunities to reach a broader audience from the general visitor to graduate students. An example of a program for the general visitor is the Reptile Discovery Center at the National Zoological Park. In this project, three reptile houses were changed into learning centers that allowed people to pace their learning, make choices, manipulate objects, and talk with interpreters. Zoo programs for secondary students are rare, but some zoos have explorer scout training posts or conservation clubs for this audience. There are programs in toes for the training of zoo herpetologists. The Santa Fc Community College in Gainesville, Florida offers such a training course. Tire National Zoological Park and other toes provide undergraduate and graduate student grants to do research with animals in a zoo setting. A few zoos even offer postdoctoral research fellowships to work with zoo animals. In spite of the above programs, there is no real formal liaison between a zoological garden or aquarium and an academic institution. A liaison is described in which a university and a zoo could cooperate in a graduate program in conservation biology. The university could provide the students and the formal course work while the zoo could provide office space and animals. Although the ontogeny of learning opportunities is great in toes and aquariums, most institutions have not taken the opportunity to reach a broader audience with herpetology. C1 Smithsonian Inst, Natl Zool Pk, Dept Herpetol, Washington, DC 20008 USA. RP Marcellini, DL (reprint author), Smithsonian Inst, Natl Zool Pk, Dept Herpetol, Washington, DC 20008 USA. NR 14 TC 4 Z9 5 U1 9 U2 25 PU HERPETOLOGISTS LEAGUE PI JOHNSON CITY PA EAST TENNESSEE STATE UNIV, DEPT BIOLOGICAL SCIENCES, BOX 70726, JOHNSON CITY, TN 37614-0726 USA SN 0018-0831 J9 HERPETOLOGICA JI Herpetologica PD JUN PY 1998 VL 54 SU S BP S12 EP S16 PG 5 WC Zoology SC Zoology GA ZU653 UT WOS:000074219600004 ER PT J AU Crockett, CM AF Crockett, CM TI Conservation biology of the genus Alouatta SO INTERNATIONAL JOURNAL OF PRIMATOLOGY LA English DT Article DE Alouatta; howler monkey; population assessment; habitat fragmentation ID MANTLED HOWLING MONKEYS; PREY CHOICE; LA-PACIFICA; COSTA-RICA; POPULATION; PATTERNS; HABITAT; DIET; DEMOGRAPHY; SENICULUS AB As assessed by the IUCN Mace-Lande system, seven (35%) of the 20 Alouatta species and subspecies with adequate data are classified as "threatened," i.e., critically endangered, endangered, or vulnerable (Rylands et al, 1995). This percentage is much lower than the 75 to 100% threatened taxa for, the other large-bodied genera: Ateles, Lagothrix, and Brachyteles. Only 5 of the 16 Neotropical genera have lower percentages of threatened taxa than that of Alouatta: Cebuella, Pithecia, Saguinus, Saimiri, and Cebus The threatened howler taxa occupy small distributions in areas of forest fragmentation. In general, populations are most affected by major habitat disturbance, such as total deforestation and flooding from dam construction, and by human hunters. Facilitated by their ability to exploit folivorous diets in small home ranges, howlers can tolerate considerable habitat fragmentation but not the increased exposure to hunting that may accompany it. Howlers seem particularly vulnerable to yellow fever and bot fly parasitism. Although the former threat may decrease by increasing fragmentation of the habitat, other sorts of parasitism may ino ease in disturbed habitats. The Low genetic variability of the Central American howlers suggests a resistance to inbreeding depression potentially experienced during population bottlenecks. Greater between-population variability may still exist. Although howlers are not readily bred in captivity, they respond well to translocation. Translocation has been successfully achieved for greater than or equal to 4 howler species and is a viable option for introducing new genetic variability into population fragments and repopulating areas from which howlers are extinct. Their pattern of bisexual dispersal facilitates colonization of regenerating habitats, and in suitable, protected habitats they have shown the capacity for strong population recovery. C1 Univ Washington, Reg Primate Res Ctr, Seattle, WA 98195 USA. Smithsonian Inst, Natl Zool Pk, Washington, DC 20008 USA. RP Crockett, CM (reprint author), Univ Washington, Reg Primate Res Ctr, Box 357330, Seattle, WA 98195 USA. NR 150 TC 73 Z9 84 U1 1 U2 16 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0291 J9 INT J PRIMATOL JI Int. J. Primatol. PD JUN PY 1998 VL 19 IS 3 BP 549 EP 578 DI 10.1023/A:1020316607284 PG 30 WC Zoology SC Zoology GA ZX056 UT WOS:000074465000009 ER PT J AU Molella, A AF Molella, A TI Eloges - Stanley Goldberg, 4 August 1933 16 October 1996 SO ISIS LA English DT Biographical-Item C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Sci & Technol, Washington, DC 20560 USA. RP Molella, A (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Sci & Technol, NMAH-5119, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0021-1753 J9 ISIS JI Isis PD JUN PY 1998 VL 89 IS 2 BP 312 EP 315 DI 10.1086/384003 PG 4 WC History & Philosophy Of Science SC History & Philosophy of Science GA ZX051 UT WOS:000074475300005 ER PT J AU Withuhn, WL AF Withuhn, WL TI Early American railroads: Franz Anton Ritter von Gerstner's Die innern Communicationen (1842-1843). SO ISIS LA English DT Book Review C1 Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. RP Withuhn, WL (reprint author), Smithsonian Inst, 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 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0021-1753 J9 ISIS JI Isis PD JUN PY 1998 VL 89 IS 2 BP 351 EP 352 DI 10.1086/384041 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA ZX051 UT WOS:000074475300045 ER PT J AU Jakab, PL AF Jakab, PL TI Airplane stability and control: A history of the technologies that made aviation possible. SO ISIS LA English DT Book Review C1 Smithsonian Inst, Natl Air & Space Museum, Dept Aeronaut, Washington, DC 20560 USA. RP Jakab, PL (reprint author), Smithsonian Inst, Natl Air & Space Museum, Dept Aeronaut, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0021-1753 J9 ISIS JI Isis PD JUN PY 1998 VL 89 IS 2 BP 363 EP 364 DI 10.1086/384055 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA ZX051 UT WOS:000074475300059 ER PT J AU Warner, D AF Warner, D TI The Ballast-Office time ball and the subjectivity of time and space SO JAMES JOYCE QUARTERLY LA English DT Article C1 Smithsonian Inst, Amer Museum Nat Hist, Washington, DC 20560 USA. RP Warner, D (reprint author), Smithsonian Inst, Amer Museum Nat Hist, Washington, DC 20560 USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU UNIV TULSA PI TULSA PA JAMES JOYCE QUARTERLY 600 SOUTH COLLEGE AVE, TULSA, OK 74104-3189 USA SN 0021-4183 J9 JAMES JOYCE QUART JI James Joyce Q. PD SUM-FAL PY 1998 VL 35 IS 4 BP 861 EP 864 PG 4 WC Literature, British Isles SC Literature GA 318PK UT WOS:000087292700027 ER PT J AU Collins, MJ AF Collins, MJ TI Countdown: A history of space flight 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 1998 VL 85 IS 1 BP 307 EP 307 DI 10.2307/2568571 PG 1 WC History SC History GA 109MP UT WOS:000075326600141 ER PT J AU Basset, Y Novotny, V Miller, SE Springate, ND AF Basset, Y Novotny, V Miller, SE Springate, ND TI Assessing the impact of forest disturbance on tropical invertebrates: some comments SO JOURNAL OF APPLIED ECOLOGY LA English DT Editorial Material ID SPECIES ABUNDANCE PATTERNS; RAIN-FOREST; COMMUNITY STRUCTURE; BODY-SIZE; ASSEMBLAGES; DIVERSITY; BIOMASS; BIODIVERSITY; DISTRIBUTIONS; CONSERVATION C1 Int Inst Entomol, London SW7 5JR, England. Acad Sci Czech Republ, Inst Entomol, CR-37005 Ceske Budejovice, Czech Republic. Univ S Bohemia, Ceske Budejovice 37005, Czech Republic. Int Ctr Insect Physiol & Ecol, Nairobi, Kenya. Bishop Museum, Honolulu, HI USA. Museum Nat Hist, Dept Entomol, London SW7 5BD, England. RP Basset, Y (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Ancon, Panama. RI Basset, Yves/B-6642-2014; Novotny, Vojtech/G-9434-2014; OI Novotny, Vojtech/0000-0001-7918-8023; Miller, Scott/0000-0002-4138-1378 NR 64 TC 38 Z9 45 U1 0 U2 3 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0021-8901 J9 J APPL ECOL JI J. Appl. Ecol. PD JUN PY 1998 VL 35 IS 3 BP 461 EP 466 DI 10.1046/j.1365-2664.1998.00311.x PG 6 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 122YZ UT WOS:000076100200011 ER PT J AU Tarof, SA Stutchbury, BJM Piper, WH Fleischer, RC AF Tarof, SA Stutchbury, BJM Piper, WH Fleischer, RC TI Does breeding density covary with extra-pair fertilizations in Hooded Warblers? SO JOURNAL OF AVIAN BIOLOGY LA English DT Article ID SWALLOW HIRUNDO-RUSTICA; GREAT REED WARBLER; TREE SWALLOWS; EASTERN BLUEBIRDS; MONOGAMOUS BIRD; LOW-FREQUENCY; URIA-AALGE; PATERNITY; COPULATIONS; DNA AB The extent of variation in the frequency of extra-pair matings among and within avian species could result from differences in breeding density, where breeding density is predicted to be positively correlated with extra-pair paternity. We combined paternity data and behavioural observations to evaluate this prediction using correlational data in relation to observed densities of Hooded Warblers Wilsonia citrina by comparing populations differing in (1) nearest neighbour distance which varied by more than an order of magnitude (range 50-600 m) and (2) the number of adjacent neighbours within 300 m (range 0-8). Spearman rank correlations demonstrated no relationship between extra-pair paternity and either inter-territory distance or the number of adjacent neighbours within 300 m. The rate of extra-territorial forays, female chip rates, the number of chipping bouts, time spent chipping, male song rates, the number of song bouts and time spent singing were similar among pairs breeding at different densities. Our results suggest that a simple linear relationship between density and extra-pair paternity may not exist in some avian species, possibly because the costs of inter-territory travel may be much lower than the benefits gained through extra-pair fertilizations, and also because of the conflicting mating tactics used by males and females. C1 Queens Univ, Dept Biol, Kingston, ON K7L 3N6, Canada. York Univ, N York, ON M3J 1P3, Canada. Smithsonian Inst, Natl Zool Pk, Genet Mol Lab, Washington, DC 20008 USA. RP Tarof, SA (reprint author), Queens Univ, Dept Biol, Kingston, ON K7L 3N6, Canada. EM tarofs@biology.queensu.ca NR 59 TC 24 Z9 24 U1 3 U2 9 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0908-8857 J9 J AVIAN BIOL JI J. Avian Biol. PD JUN PY 1998 VL 29 IS 2 BP 145 EP 154 DI 10.2307/3677192 PG 10 WC Ornithology SC Zoology GA ZV434 UT WOS:000074304200007 ER PT J AU Stanley, DJ Warne, AG AF Stanley, DJ Warne, AG TI Nile delta in its destruction phase SO JOURNAL OF COASTAL RESEARCH LA English DT Article; Proceedings Paper CT World Deltas Symposium CY AUG 23-29, 1998 CL NEW ORLEANS, LA SP Ocean Energy Inc DE Aswan dams; barrages; canals; coastal erosion; delta construction; delta destruction; diseases; drill cores; Egypt; industrial waste; lagoons; Lake Nasser; land conversion; Mediterranean Sea; Nile Cone; Nile delta; pollution; population pressure; River Nile; salinization; waterways; wetlands ID LATE QUATERNARY STRATIGRAPHY; SEA-LEVEL; PALEOCLIMATIC OSCILLATIONS; SEDIMENT DISPERSAL; RECENT SUBSIDENCE; HEAVY MINERALS; EGYPT; EVOLUTION; COAST; HOLOCENE AB All deltas undergo alternating construction to destruction phases due to fundamental changes in the relative influence of sediment input from rivers and redistribution by marine coastal processes. During the past 7000 years world deltas, including the Nile, have been in an overall construction phase. However, the Nile delta has converted to a destruction phase during the past 150 years, triggered by water regulation which has disrupted the balance among sediment influx, erosive effects of coastal processes, and subsidence. This former depocenter has been altered to the extent that it is no longer a functioning delta but, rather, a subsiding and eroding coastal plain. Symptoms of the destruction phase of the Nile delta include accelerated coastal erosion and straightening of the shoreline, reduction in wetland size, increased landward incursion of saline groundwater, and buildup of salt and pollutants to toxic levels in wetlands and delta plain. Without seasonal flushing by floods, the former delta plain surface is now incapable of recycling and/or removing agricultural, municipal and industrial wastes generated by Egypt's rapidly expanding population. Moreover, the remaining capacity of the system to regenerate itself will further diminish as water is diverted away from the delta for new irrigation and municipal projects in the Egyptian desert, and water allocations to Egypt are decreased by upstream countries. Reestablishing some level of natural hydrology is the only credible solution for attaining equilibrium among sediment accretion on the delta plain to offset subsidence, progradation along the coast to offset erosion, and sufficient water influx to flush and remove the high levels of salt and pollutants throughout the system. However, increased Nile water and sediment discharge could begin to restore a functioning delta system only if there is a substantial reduction in human impacts. C1 Smithsonian Inst, Deltas Global Change Program, Washington, DC 20560 USA. CEWES, GG, YH, Waterways Expt Stn, Vicksburg, MS 39180 USA. RP Stanley, DJ (reprint author), Smithsonian Inst, Deltas Global Change Program, E-206 NMNH, Washington, DC 20560 USA. NR 163 TC 131 Z9 142 U1 4 U2 49 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 1998 VL 14 IS 3 BP 794 EP 825 PG 32 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 111DB UT WOS:000075421100008 ER PT J AU de Blois, ST Novak, MA Bond, M AF de Blois, ST Novak, MA Bond, M TI Object permanence in orangutans (Pongo pygmaeus) and squirrel monkeys (Saimiri sciureus) SO JOURNAL OF COMPARATIVE PSYCHOLOGY LA English DT Article ID CHIMPANZEES PAN-TROGLODYTES; CATS FELIS-CATUS; PARROT PSITTACUS-ERITHACUS; DOGS CANIS-FAMILIARIS; INFANT RHESUS-MONKEY; SELF-RECOGNITION; CAPUCHIN MONKEYS; WILD CHIMPANZEES; SEARCH BEHAVIOR; MACACA-MULATTA AB The authors tested orangutans (Pongo pygmaeus) and squirrel monkeys (Saimiri sciureus) on object permanence tasks. In Experiment 1, orangutans solved all visible displacements and most invisible displacements except those involving movements into 2 boxes successively In Experiment 2, performance of orangutans on double invisible displacements and control displacements (assessing simple strategies) was compared. Orangutans did not use the simple strategy of selecting the box visited last by the experimenter. instead, poorer performance on double invisible displacements may have been related to increased memory requirements. in Experiment 3, squirrel monkeys were tested using the procedure of Experiment 1. Squirrel monkeys solved visible but did not comprehend invisible displacements. Results suggest that orangutans but not squirrel monkeys possess Stage 6 object permanence capabilities. C1 Univ Massachusetts, Dept Psychol, Amherst, MA 01003 USA. Smithsonian Inst, Primate Unit, Natl Zool Pk, Washington, DC 20560 USA. RP de Blois, ST (reprint author), Harvard Univ, Sch Med, Div Behav Biol, New England Reg Primate Res Ctr, 1 Pine Hill Dr, Southborough, MA 01772 USA. EM sdeblois@warren.med.harvard.edu NR 79 TC 67 Z9 68 U1 3 U2 20 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0735-7036 J9 J COMP PSYCHOL JI J. Comp. Psychol. PD JUN PY 1998 VL 112 IS 2 BP 137 EP 152 DI 10.1037/0735-7036.112.2.137 PG 16 WC Behavioral Sciences; Psychology; Psychology, Multidisciplinary; Zoology SC Behavioral Sciences; Psychology; Zoology GA ZU125 UT WOS:000074164800004 PM 9642783 ER PT J AU Walter, TC AF Walter, TC TI A redescription of Pseudodiaptomus salinus (Giesbrecht, 1896) and a new species from the Arabian Sea (Copepoda, Calanoida, Pseudodiaptomidae) SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT 6th International Conference on Copepoda CY JUL 29-AUG 03, 1996 CL OLDENBURG, GERMANY DE Calanoida; Pseudodiaptomus; taxonomy; Arabian Sea; Red Sea; Copepoda AB Many species of Pseudodiaptomus are known from the Indian Ocean. However, only two species have been reported from the Red and Arabian Seas. A review of P. salinus (Giesbrecht) from collections near Kuwait and Pakistan in the Arabian Sea revealed differences from Red Sea material. Further study proved the existence of a new species Pseudodiaptomus arabicus n.sp. C1 Smithsonian Inst, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Walter, TC (reprint author), Smithsonian Inst, Dept Invertebrate Zool, MRC-163, Washington, DC 20560 USA. NR 15 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD JUN PY 1998 VL 15 IS 1-4 BP 451 EP 456 PG 6 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 101NY UT WOS:000074876100052 ER PT J AU Adey, WH AF Adey, WH TI Coral reefs: Algal structured and mediated ecosystems in shallow, turbulent, alkaline waters SO JOURNAL OF PHYCOLOGY LA English DT Review DE algae; calcification; community structure; coral reef; primary production; zooxanthellae ID COMMUNITY STRUCTURE; CARBON-DIOXIDE; CALCIUM-CARBONATE; HERBIVOROUS FISHES; FRENCH-POLYNESIA; PHASE-SHIFTS; SEA; CALCIFICATION; OCEAN; PHOTOSYNTHESIS C1 Smithsonian Inst, Marine Syst Lab, Washington, DC 20560 USA. RP Adey, WH (reprint author), Smithsonian Inst, Marine Syst Lab, Washington, DC 20560 USA. NR 72 TC 90 Z9 94 U1 5 U2 23 PU PHYCOLOGICAL SOC AMER INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0022-3646 J9 J PHYCOL JI J. Phycol. PD JUN PY 1998 VL 34 IS 3 BP 393 EP 406 DI 10.1046/j.1529-8817.1998.340393.x PG 14 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA ZZ445 UT WOS:000074730100001 ER PT J AU Chance, KV Park, K Evenson, KM AF Chance, KV Park, K Evenson, KM TI Pressure broadening of far infrared rotational transitions: 88.65 CM-1 H2O and 114.47 CM-1 O-3 SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID DATABASE; N2; O2 AB We measured N-2 and O-2 pressure broadening coefficients for the 88.65 cm(-1) line of H2O at 290 K and the 114.47 cm(-1) line of O-3 at 290 and 210 K. Broadening measurements of these lines also include determinations of the self broadening and a frequency measurements of the transitions. Published by Elsevier Science Ltd. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Park, K (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 6 TC 7 Z9 7 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 JUN PY 1998 VL 59 IS 6 BP 687 EP 688 DI 10.1016/S0022-4073(97)00153-2 PG 2 WC Optics; Spectroscopy SC Optics; Spectroscopy GA ZG314 UT WOS:000072988900010 ER PT J AU Richman, LK Bush, M AF Richman, LK Bush, M TI Patellar tendon rupture in five deer SO JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION LA English DT Article AB Patellar tendon rupture in humans is associated with underlying systemic disease, such as systemic lupus erythematosus, rheumatoid arthritis, or chronic renal failure. Patellar tendon rupture in Pere David's deer without evidence of an underlying systemic disease should be considered a sequela to age-related tendon degeneration compounded by sudden exertion and chronic overload attributable to obesity. C1 Smithsonian Inst, Natl Zool Pk, Dept Pathol, Washington, DC 20008 USA. Smithsonian Inst, Natl Zool Pk, Conservat & Res Ctr, Front Royal, VA 22630 USA. RP Richman, LK (reprint author), Smithsonian Inst, Natl Zool Pk, Dept Pathol, Washington, DC 20008 USA. NR 9 TC 2 Z9 2 U1 0 U2 1 PU AMER VETERINARY MEDICAL ASSOC PI SCHAUMBURG PA 1931 N MEACHAM RD SUITE 100, SCHAUMBURG, IL 60173-4360 USA SN 0003-1488 J9 J AM VET MED ASSOC JI J. Am. Vet. Med. Assoc. PD JUN 1 PY 1998 VL 212 IS 11 BP 1776 EP 1778 PG 3 WC Veterinary Sciences SC Veterinary Sciences GA ZR476 UT WOS:000073980700022 PM 9621888 ER PT J AU Florentine, F AF Florentine, F TI Effective constrained illumination of three-dimensional, light-sensitive objects - Discussion SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Editorial Material C1 Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. RP Florentine, F (reprint author), Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1998 VL 27 IS 2 BP 128 EP 129 PG 2 WC Optics SC Optics GA 108FW UT WOS:000075256300058 ER PT J AU Robinson, E AF Robinson, E TI Effective constrained illumination of three-dimensional, light-sensitive objects - Discussion SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Editorial Material C1 Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. RP Robinson, E (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1998 VL 27 IS 2 BP 128 EP 128 PG 1 WC Optics SC Optics GA 108FW UT WOS:000075256300057 ER PT J AU Hildebrandt, TB Goritz, F Pratt, NC Schmitt, DL Quandt, S Raath, J Hofmann, RR AF Hildebrandt, TB Goritz, F Pratt, NC Schmitt, DL Quandt, S Raath, J Hofmann, RR TI Reproductive assessment of male elephants (Loxodonta africana and Elephas maximus) by ultrasonography SO JOURNAL OF ZOO AND WILDLIFE MEDICINE LA English DT Article DE male elephants; anatomy; ultrasonography; reproduction; Loxodonta africana; Elephas maximus ID ASIAN ELEPHANT; TESTOSTERONE CONCENTRATIONS; SERUM TESTOSTERONE; MUSTH; CASTRATION AB Transrectal ultrasonography was performed on five wild and two captive male African elephants (Loxodonta africana) and four captive male Asian elephants (Elephas maximus) to develop standards for assessment of reproductive health and status. The entire internal urogenital tract was visualized ultrasonographically by using a 3.5 MHz or a 7.5-MHz transducer in combination with a probe extension adapted for elephant anatomy. The findings were verified by postmortem ex situ ultrasound examinations in several individuals of each species. Each part of the internal urogenital tract was sonographically detectable except for the bulbourethral glands and the cranial portion of the ureters and ductus deferentes, which were only observed in situ in the neonate. Each structure visualized was measured and described. The size and morphology of the urogenital structures, especially the accessory glands, were indicative of breeding status, if known. There was a notable difference between African and Asian males in the size and morphology of the prostate gland and a slight difference in the shape of the ampullae. No other structure showed significant species differences. The detection of the location and description of the testes may provide information for modifying present castration procedures. Furthermore, ultrasound examination of the male accessory glands may aid in the identification of potential semen donors for assisted reproduction programs in captive elephants. C1 Inst Zoo Biol & Wildlife Res, Dept Ultrasound, D-10315 Berlin, Germany. Smithsonian Inst, Natl Zool Pk, Dept Mammals, Washington, DC 20008 USA. Dickerson Pk Zoo, Dept Vet Med, Springfield, MO 65803 USA. Univ Pretoria, Fac Vet Sci, ZA-0110 Onderstepoort, South Africa. Kruger Natl Pk, Skukuza, South Africa. Inst Zoo Biol & Wildlife Res, Dept Morphol, D-10315 Berlin, Germany. RP Hildebrandt, TB (reprint author), Inst Zoo Biol & Wildlife Res, Dept Ultrasound, Alfred Kowalke Str 17, D-10315 Berlin, Germany. NR 49 TC 21 Z9 23 U1 0 U2 10 PU AMER ASSOC Z00 VETERINARIANS PI MEDIA PA 6 NORTH PENNELL ROAD, MEDIA, PA 19063 USA SN 1042-7260 J9 J ZOO WILDLIFE MED JI J. Zoo Wildl. Med. PD JUN PY 1998 VL 29 IS 2 BP 114 EP 128 PG 15 WC Veterinary Sciences SC Veterinary Sciences GA 113NR UT WOS:000075558600002 PM 9732024 ER PT J AU Monfort, SL Mashburn, KL Brewer, BA Creel, SR AF Monfort, SL Mashburn, KL Brewer, BA Creel, SR TI Evaluating adrenal activity in African wild dogs (Lycaon pictus) by fecal corticosteroid analysis SO JOURNAL OF ZOO AND WILDLIFE MEDICINE LA English DT Article DE Lycaon pictus; fecal corticosteroids; ACTH; adrenal gland; stress; hormones ID OVIS-CANADENSIS-CANADENSIS; SERENGETI DWARF MONGOOSES; URINARY CORTISOL; RHESUS-MONKEYS; MULE DEER; RESPONSES; FELIDS; STRESS; SHEEP; FECES AB A noninvasive corticosteroid hormone monitoring technique was validated for use in African wild dogs (Lycaon pictus). The double-antibody I-125 radioimmunoassay for corticosterone was validated by demonstrating parallelism between serial dilutions of wild dog fecal extracts and the standard curve, recovery of corticosterone added to fecal extracts, and the time course of fecal corticoid excretion after an exogenous adrenocorticotropic hormone (ACTH) challenge. All feces were collected from three female and two male African wild dogs for 72 hr before and 144 hr after i.m. injection of long-acting ACTH (Acthar Gel, 400 IU). Fecal corticosterone immunoreactivity increased 10-30-fold within 24 hr of ACTH administration in all individuals, with peak concentrations from 1,200-8,000 ng/g. High pressure liquid chromatography analysis revealed that >90% of all corticosterone immunoreactivity was associated with a single peak that exhibited intermediate polarity relative to cortisol and corticosterone reference tracers. Fecal corticosterone immunoreactivity appears to reflect adrenal activity in the African wild dog and, therefore, may be useful for evaluating stress. From a conservation perspective, these techniques can complement in situ and ex situ research studies designed to evaluate how environmental conditions and management strategies affect overall animal health. C1 Smithsonian Inst, Natl Zool Pk, Conservat & Res Ctr, Front Royal, VA 22630 USA. Rockefeller Univ, Field Res Ctr Ecol & Ethol, Millbrook, NY 12545 USA. Chicago Zool Soc, Brookfield Zoo, Brookfield, IL 60513 USA. RP Monfort, SL (reprint author), Smithsonian Inst, Natl Zool Pk, Conservat & Res Ctr, 1500 Remount Rd, Front Royal, VA 22630 USA. NR 31 TC 69 Z9 71 U1 0 U2 15 PU AMER ASSOC Z00 VETERINARIANS PI MEDIA PA 6 NORTH PENNELL ROAD, MEDIA, PA 19063 USA SN 1042-7260 J9 J ZOO WILDLIFE MED JI J. Zoo Wildl. Med. PD JUN PY 1998 VL 29 IS 2 BP 129 EP 133 PG 5 WC Veterinary Sciences SC Veterinary Sciences GA 113NR UT WOS:000075558600003 PM 9732025 ER PT J AU Tardif, S Jaquish, C Layne, D Bales, K Power, M Power, R Oftedal, O AF Tardif, S Jaquish, C Layne, D Bales, K Power, M Power, R Oftedal, O TI Growth variation in common marmoset monkeys (Callitrix jacchus) fed a purified diet: Relation to care-giving and weaning behaviors SO LABORATORY ANIMAL SCIENCE LA English DT Article ID CALLITHRIX-JACCHUS; MATERNAL-CARE; SURVIVAL; PRIMATES AB Significant relations were observed between select infant-care and weaning behaviors and growth in body weight in common marmoset monkeys (Callithrix jacchus). The patterns of these relations suggest that earlier occurrence of developmental milestones, such as cessation of transport (being off carriers) and weaning to solid food, were associated with slower growth duping the subsequent period. In contrast, more frequent nursing bouts during the period in which weaning was initiated were associated with higher growth rates. In the case of being off carriers, these effects did not carry over to older ages, suggesting that any deficits in growth were temporary. In the case of earlier; more frequent consumption of solid food, there was some suggestion that there were longer-term effects, followed by catch-up growth. The knee-to-heel length of subjects was not related to the measured behaviors. There was no relation between early weaning to solid food and leanness at day 75, suggesting that, although this behavior was affecting overall weight, it did not affect relative gains of fat versus lean mass, There were, however, significant correlations between cessation of transport or frequency of nursing bouts during the weaning period and leanness, with earlier cessation of transport and less frequent nursing associated with leaner infants, after weaning. Our results differed from those of a previous study that found a relation between linear growth and abuse in this species, with abuse defined as physical injury by other members of the group. We found no differences in growth between abused and nonabused infants. However, abused infants had lower birth weight. C1 Kent State Univ, Dept Biol Sci, Kent, OH 44242 USA. NHLBI, NIH, Bethesda, MD 20892 USA. Univ Maryland, Dept Zool, College Pk, MD 20742 USA. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Tardif, S (reprint author), Kent State Univ, Dept Biol Sci, POB 5190,Cunningham Hall, Kent, OH 44242 USA. FU NCRR NIH HHS [R01-RR02022] NR 33 TC 28 Z9 28 U1 1 U2 7 PU AMER ASSOC LABORATORY ANIMAL SCIENCE PI CORDOVA PA 70 TIMBERCREEK DR, SUITE 5, CORDOVA, TN 38018 USA SN 0023-6764 J9 LAB ANIM SCI JI Lab. Anim. Sci. PD JUN PY 1998 VL 48 IS 3 BP 264 EP 269 PG 6 WC Veterinary Sciences; Zoology SC Veterinary Sciences; Zoology GA 123ZZ UT WOS:000076157000010 PM 10090026 ER PT J AU Riley, SM AF Riley, SM TI The doomsday report. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Libs, Washington, DC 20560 USA. RP Riley, SM (reprint author), Smithsonian Inst Libs, 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 JUN 1 PY 1998 VL 123 IS 10 BP 149 EP 149 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA ZR997 UT WOS:000074037300190 ER PT J AU Riley, SM AF Riley, SM TI Ghost children. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC 20560 USA. RP Riley, SM (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 JUN 1 PY 1998 VL 123 IS 10 BP 161 EP 162 PG 2 WC Information Science & Library Science SC Information Science & Library Science GA ZR997 UT WOS:000074037300225 ER PT J AU Jivoff, P Hines, AH AF Jivoff, P Hines, AH TI Effect of female molt stage and sex ratio ion courtship behavior of the blue crab Callinectes sapidus SO MARINE BIOLOGY LA English DT Article ID CENTRAL CHESAPEAKE BAY; MALE MATING SUCCESS; CHIONOECETES-OPILIO; ASELLUS-AQUATICUS; MATE CHOICE; ORCONECTES-RUSTICUS; HOMARUS-AMERICANUS; WATER STRIDER; SNOW CRAB; CRUSTACEA AB In many species, males and females actively participate in courtship, and the outcome of pre-mating interactions influences the mating success of both sexes, Female blue crabs, Callinectes sapidus, mate soon after their final molt to maturity. thus female molt stage dictates the timing of mating. In a field experiment, we manipulated female molt stage and sex ratio to test their effects on the courtship behavior of both sexes. if female behavior influences the behavior and pairing success of males, and if male courtship influences male pairing-success. Early-molt-stage females avoided males during courtship, whereas late-molt-stage females sought out males. As a result, males had to pursue and capture early-molt-stage females whereas males displayed to late-molt-stage females and more easily physically controlled them, Males sometimes abandoned late-molt-stage females. but this occurred more often when females were abundant. The rate at which females avoided males was positively correlated with that of males abandoning females. and males that were unsuccessful at pairing met with higher rates of female resistance than successful males, suggesting that female behavior influences male pairing-success. Unlike unsuccessful males. successful males more often made the transition between display and maintaining physical control of the female. At high male sex ratios, males initiated courtship more readily: thus both sexual competition and female behavior influence male courtship in this species. C1 Univ Maryland, Dept Zool, College Pk, MD 20742 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Jivoff, P (reprint author), Rutgers State Univ, Marine Field Stn, 800 Great Bay Blvd, Tuckerton, NJ 08087 USA. NR 78 TC 17 Z9 17 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD JUN PY 1998 VL 131 IS 3 BP 533 EP 542 DI 10.1007/s002270050345 PG 10 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 110JY UT WOS:000075378700014 ER PT J AU Tarr, CL Conant, S Fleischer, RC AF Tarr, CL Conant, S Fleischer, RC TI Founder events and variation at microsatellite loci in an insular passerine bird, the Laysan finch (Telespiza cantans) SO MOLECULAR ECOLOGY LA English DT Article DE Hawaiian honeycreeper; endangered species; founder events; effective population size; microsatellites; primers ID EFFECTIVE POPULATION-SIZE; GENETIC-VARIATION; CAPTIVE POPULATIONS; JUVENILE MORTALITY; NATURAL-POPULATION; MULTIPLE ALLELES; HARDY-WEINBERG; BOTTLENECK; DIFFERENTIATION; CONSERVATION AB Historically documented founder events provide opportunities to assess the effects of population size reductions on genetic variation, but the actual magnitude of genetic change can be measured only when direct comparisons can be made to the source or ancestral population. We assayed variation at nine microsatellite loci in the translocated population of the Laysan finch (Telespiza cantans) at Pearl and Hermes reef (PHR), and compared the level of variation to that in the source population pn Laysan Island. Heterogeneity in allele frequencies was highly significant at eight of the nine loci, primarily as a result of fluctuations in allele frequencies in the three PHR populations. Intra- and interpopulational measures of genetic diversity generally matched predictions based on the well-documented history of three islet populations at PHR: significantly lower numbers of alleles and polymorphic loci, as well as higher pairwise F(ST) values and genetic distance, were observed for the two populations that underwent severe size reductions. Changes in heterozygosity at single loci were unpredictable, as both significant increases and decreases were observed in founder populations. A significant excess of heterozygotes was found in two populations and was highly significant over all four finch populations (P < 0.003). Estimates of effective population size from temporal changes in heterozygosity and allele frequencies were very small (N(e) less than or equal to 30) as a result of the founding events and the constraints of islet area on population numbers. We concluded that the PHR population is not adequate as a secondary genetic reserve for T. cantans, and an alternative refuge needs to be established. C1 Penn State Univ, Dept Biol, University Pk, PA 16802 USA. Penn State Univ, Inst Mol Evolutionary Genet, University Pk, PA 16802 USA. Univ Hawaii, Dept Zool, Honolulu, HI 96822 USA. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Tarr, CL (reprint author), Penn State Univ, Dept Biol, 208 Mueller Lab, University Pk, PA 16802 USA. NR 71 TC 70 Z9 73 U1 1 U2 11 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD JUN PY 1998 VL 7 IS 6 BP 719 EP 731 DI 10.1046/j.1365-294x.1998.00385.x PG 13 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA ZU801 UT WOS:000074236300006 ER PT J AU Vinko, J Evans, NR Kiss, LL Szabados, L AF Vinko, J Evans, NR Kiss, LL Szabados, L TI Spectroscopic survey of field Type II Cepheids SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars : atmospheres; stars : oscillations; Cepheids ID H-ALPHA; INFRARED-SPECTROSCOPY; ATMOSPHERIC MOTIONS; VELOCITY CURVES; BL HERCULIS; W-VIRGINIS; AU-PEGASI; X-CYGNI; TX-DEL; LINE AB A sample of relatively bright, short-and intermediate-period (P = 1-10 d) Type II Cepheids in the Galactic field have been observed spectroscopically with an intermediate-resolution (lambda/Delta lambda = 11000) spectrograph. The wavelength region was 6500-6700 Angstrom, including the H alpha line and some photospheric iron lines, The signal-to-noise ratio (S/N) was usually between 50 and 100, depending on weather conditions and the brightness of target stars. Radial velocities were determined by cross-correlating the Cepheid spectra with those of selected IAU velocity standard stars having F-G spectral types. The internal error of the velocity determination process was calculated to be about 1 km s(-1). H alpha emission and strong line splitting were observed in BL Her during the expansion phase, but no similar phenomenon was detected in any other stars in this programme, except for AU Peg which has an unusual H alpha line showing a P Cygni-like profile. The velocity curve agrees well with recent CORAVEL measurements. The velocity gradients in Cepheid atmospheres are studied using the H alpha minus metallic velocities. Similar data an collected from the literature, It seems that having large velocity differences (nu(H alpha) - nu(metal) > 40 km s(-1)) is a characteristic feature of the very short-period (P < 1.5 d) and longer period (P > 10 d) Cepheids. Between these period regions the Cepheid atmospheres exhibit smaller velocity differences. Most of the Type IT Cepheids observed in the present study fall into this latter category, There might be a tendency for classical Cepheids of intermediate period to have larger maximum velocity differences. C1 Hungarian Acad Sci, Res Grp Laser Phys, H-6720 Szeged, Hungary. JATE Univ, Dept Opt, H-6720 Szeged, Hungary. York Univ, Dept Phys & Astron, Toronto, ON M3J 2R7, Canada. Smithsonian Astrophys Observ, Cambridge, MA USA. JATE Univ, Dept Expt Phys, Szeged, Hungary. Konkoly Observ Budapest, H-1525 Budapest, Hungary. RP Vinko, J (reprint author), Hungarian Acad Sci, Res Grp Laser Phys, Dom Ter 9, H-6720 Szeged, Hungary. RI Kiss, Laszlo/A-2539-2008; OI Vinko, Jozsef/0000-0001-8764-7832 NR 38 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 JUN 1 PY 1998 VL 296 IS 4 BP 824 EP 838 DI 10.1046/j.1365-8711.1998.01389.x PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU228 UT WOS:000074175100008 ER PT J AU Hardcastle, MJ Worrall, DM Birkinshaw, M AF Hardcastle, MJ Worrall, DM Birkinshaw, M TI Dynamics of the radio galaxy 3C 449 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; galaxies : individual : 3C 449; galaxies : jets; X-rays : galaxies ID X-RAY-EMISSION; LOW LUMINOSITY; JETS; LOBES; ENVIRONMENT; 3C449; GAS AB We present ROSAT PSPC observations of the twin-jet radio galaxy 3C 449. The soft X-ray emission from this object is dominated by an extended halo with a scale comparable to that of the radio source. The asymmetry of the X-ray emission is reflected in that of the radio lobes, providing evidence that the behaviour of the jets is strongly influenced by the external medium, A region of reduced X-ray surface brightness coincident with the southern radio lobe of 3C 449 suggests that the radio source has displaced thermal plasma from the X-ray-emitting halo. However, the minimum pressure in the radio lobe is considerably lower than our estimates of the pressure in the external medium. We discuss the implications for the dynamics of the radio source. C1 Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Hardcastle, MJ (reprint author), Univ Bristol, Dept Phys, Tyndall Ave, Bristol BS8 1TL, Avon, England. RI Hardcastle, Martin/E-2264-2012 OI Hardcastle, Martin/0000-0003-4223-1117 NR 29 TC 39 Z9 39 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 1 PY 1998 VL 296 IS 4 BP 1098 EP 1104 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU228 UT WOS:000074175100034 ER PT J AU Acevedo-Rodriguez, P AF Acevedo-Rodriguez, P TI Novelties in neotropical Sapindaceae II. Notes on Averrhoidium, Serjania, and Porocystis SO NOVON LA English DT Article AB The study of recently collected specimens of neotropical Sapindaceae reveals the need for various taxonomic changes. Matayba spondioides Standley from Mexico is transferred to Averrhoidium; Palluinia lachnocarpa Bentham ex Radlkofer (Chimborazoa lachnocarpa (Bentham ex Radlkofer) H. Beck) from Ecuador is transferred to Serjania (therefore, Chimborazoa is reduced to the synonymy of Serjania); and Toulicia acuminata Radlkofer from Amazonas, Brazil, is transferred to the closely related Porocystis. C1 Natl Museum Nat Hist, Dept Bot, Smithsonian Inst, Washington, DC 20560 USA. RP Acevedo-Rodriguez, P (reprint author), Natl Museum Nat Hist, Dept Bot, Smithsonian Inst, NHB-166, Washington, DC 20560 USA. NR 2 TC 4 Z9 4 U1 0 U2 1 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 1998 VL 8 IS 2 BP 105 EP 106 DI 10.2307/3391975 PG 2 WC Plant Sciences SC Plant Sciences GA 104NG UT WOS:000075020200001 ER PT J AU Soreng, RJ AF Soreng, RJ TI An infrageneric classification for Poa in North America, and other notes on sections, species, and subspecies of pea, Puccinellia, and Dissanthelium (Poaceae) SO NOVON LA English DT Article AB An infrageneric classification for the genus Poa L. in North America, new taxa, combinations, names, hybrid status, and lectotypes are proposed for forthcoming treatments of the genus in the Americas. New names, combinations, and taxa are: Dissanthelium atropidiforme (Hackel) Soreng, D. atropidiforme var. patagonicum (Parodi) Soreng, D. calycinum subsp. mathewsii (Ball) Soreng, Poa sect. Alpinae (Hegetschweiler ex Nyman) Soreng, P. sect. Dasypoa (Pilger) Soreng, P. sect. Sylvestres V. L. Marsh ex Soreng, P. arnowiae Soreng, P. chambersii Soreng, P. tovari Soreng, P. unilateralis subsp. pachypholis (Piper) D. D. Keck ex Soreng, Fi Xgaspensis Fernald, and Puccinellia atacamensis (Parodi) Soreng. Lectotypes are proposed for the following taxa: Dissanthelium sclerochloides Steudel ex E. Fournier, Poa [unranked] Arenariae Hegetschweiler, Poa [unranked] Caespitosae Fries ex Lange, Poa [unranked] Fasciculiferae Fries ex Lange, Poa [unranked] Glareosae Hegetschweiler, Poa [unranked] Hydrophilae Hegetschweiler, Poa [unranked] Macranthela K. Koch, Poa [unranked] Micranthela K. Koch, Poa [unranked] Stoloniferae Fries ex Lange, Poa [unranked] Subbulbosae Fries ex Andersson, Poa sect. Incanae V. Jirasek, Poa sect. Nervosae Rouy, Poa sect. Obsoletae Rouy, Poa sect. Spizopoa Dumortier. C1 Smithsonian Inst, Dept Bot, Washington, DC 20560 USA. RP Soreng, RJ (reprint author), Smithsonian Inst, Dept Bot, MRC-166, Washington, DC 20560 USA. NR 45 TC 13 Z9 19 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 1998 VL 8 IS 2 BP 187 EP 202 DI 10.2307/3391995 PG 16 WC Plant Sciences SC Plant Sciences GA 104NG UT WOS:000075020200020 ER PT J AU Buzas, MA Culver, SJ AF Buzas, MA Culver, SJ TI Assembly, disassembly, and balance in marine paleocommunities SO PALAIOS LA English DT Article ID ATLANTIC COASTAL-PLAIN; BENTHIC FORAMINIFERA; CONTINENTAL-MARGIN; SEA-LEVEL; DIVERSITY; PATTERNS; VIRGINIA; MIOCENE; FLUCTUATIONS; STRATIGRAPHY AB The fossil record is necessary to provide an extended temporal scale to studies of community stability and equilibrium and species longevities and origination. We addressed these topics with a large database for Cenozoic benthic foraminifera from six formations (ranging from Eocene to Pliocene) occurring in the Salisbury and Albemarle embayment(s) (SAE) of the North American. Atlantic: Coastal Plain. We also documented the worldwide fossil occurrences of the 356 species found in these formations to 142 well-dated formations, most of which are in the Atlantic and Gulf Coastal Plains and which comprise a species pool from which species are drawn during each transgression into the SAE. A Ledger was constructed with the first entry consisting of the number of immigrants to each formation, and the last the number of emigrants. Consideration of the ledger indicates a dynamic system. Faunal stability within ecological units, rapid and continual change, and balance and imbalance of immigrants versus emigrants are all observed. During transgressions, immigrants enter the SAE from the source species pool and, on the average, about half of the available species inhabit the SAE during a transgression. During regressions, emigrants disperse into various parts of the wide geographic area of the pool and about a quarter never return to the SAE. The distribution of each species' occurrence is unique in space and time. Emigrant species do not migrate to another location as a unit nor do they immigrate as a unit. Consequently, no recourse to biotic interactions or hierarchical structure is required to explain the observations presented here. Rather, environmental regime plays an important role in affecting community composition. C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Paleobiol, Washington, DC 20560 USA. Nat Hist Museum, Dept Palaeontol, London SW7 5BD, England. RP Buzas, MA (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Paleobiol, Washington, DC 20560 USA. NR 55 TC 23 Z9 23 U1 0 U2 4 PU SEPM-SOC SEDIMENTARY GEOLOGY PI TULSA PA 1731 E 71ST STREET, TULSA, OK 74136-5108 USA SN 0883-1351 J9 PALAIOS JI Palaios PD JUN PY 1998 VL 13 IS 3 BP 263 EP 275 DI 10.2307/3515449 PG 13 WC Geology; Paleontology SC Geology; Paleontology GA ZQ234 UT WOS:000073836900004 ER PT J AU Bear, D Chupp, TE Cooper, K DeDeo, S Rosenberry, M Stoner, RE Walsworth, RL AF Bear, D Chupp, TE Cooper, K DeDeo, S Rosenberry, M Stoner, RE Walsworth, RL TI Improved frequency stability of the dual-noble-gas maser SO PHYSICAL REVIEW A LA English DT Article ID ELECTRIC-DIPOLE MOMENT; VIOLATION; NEUTRON; LIMITS; HG-199; ATOMS AB We report improved frequency stability of the dual-noble-gas maser. This recently developed device can measure very small changes in the Zeeman transition frequencies of cohabitating ensembles of Xe-129 and He-3 atoms, and thus may be useful for symmetry tests and precision measurements such as a search for a permanent electric dipole moment of the Xe-129 atom. Using the dual-noble-gas maser, we measured the frequency stability (i.e., the Allan deviation) of the 3He Zeeman transition to be approximately 100 nHz in 6000 s of data acquisition. This Zeeman frequency stability is an order of magnitude improvement over our previous report. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. RP Bear, D (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Stoner, Richard/0000-0001-7949-6747 NR 18 TC 15 Z9 15 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 5006 EP 5008 DI 10.1103/PhysRevA.57.5006 PG 3 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600121 ER PT J AU Cote, R Dalgarno, A Wang, H Stwalley, WC AF Cote, R Dalgarno, A Wang, H Stwalley, WC TI Potassium scattering lengths and prospects for Bose-Einstein condensation and sympathetic cooling SO PHYSICAL REVIEW A LA English DT Article ID LONG-RANGE DISPERSION; 2 K ATOMS; ATTRACTIVE INTERACTIONS; EXCHANGE INTERACTIONS; STATE; GAS; K-2 AB We have determined the scattering lengths for collisions between the different isotopes of two potassium atoms in singlet and triplet molecular states of K-2. We show that for the two bosonic species K-39 and K-41 the scattering lengths are positive, hence, leading to stable condensates. The fermionic isotope K-40 also has positive scattering lengths, but the triplet value is nearly zero, hence, a quasi-non-interacting fermionic gas. We also give results for the interspecies collisions. We conclude that double condensates of K-39 and K-41 are possible for purely spin-polarized atoms, and sympathetic cooling between the bosonic K-39 and the fermionic K-40 will be efficient due to low spin-flip rates and a sizable interspecies scattering length. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. RP Cote, R (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 25 TC 36 Z9 36 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP R4118 EP R4121 DI 10.1103/PhysRevA.57.R4118 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600012 ER PT J AU Kalfatovic, MR AF Kalfatovic, MR TI Encyclopedia of religious controversies in the United States. SO REFERENCE & USER SERVICES QUARTERLY 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 AMER LIBRARY ASSOC PI CHICAGO PA 50 E HURON ST, CHICAGO, IL 60611 USA SN 1094-9054 J9 REF USER SERV Q JI Ref. User Serv. Q. PD SUM PY 1998 VL 37 IS 4 BP 354 EP 355 PG 2 WC Information Science & Library Science SC Information Science & Library Science GA 176KF UT WOS:000079149700034 ER PT J AU Kalfatovic, MR AF Kalfatovic, MR TI The international encyclopaedic dictionary of philately. SO REFERENCE & USER SERVICES QUARTERLY 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 AMER LIBRARY ASSOC PI CHICAGO PA 50 E HURON ST, CHICAGO, IL 60611 USA SN 1094-9054 J9 REF USER SERV Q JI Ref. User Serv. Q. PD SUM PY 1998 VL 37 IS 4 BP 363 EP 364 PG 2 WC Information Science & Library Science SC Information Science & Library Science GA 176KF UT WOS:000079149700050 ER PT J AU Heyman, IM AF Heyman, IM TI Charting a new course (Establishing a permanent marine station heralds an era of progress for Smithsonian research) SO SMITHSONIAN LA English DT Editorial Material C1 Smithsonian Inst, Washington, DC 20560 USA. RP Heyman, IM (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SMITHSONIAN ASSOCIATES PI WASHINGTON PA 900 JEFFERSON DRIVE, WASHINGTON, DC 20560 USA SN 0037-7333 J9 SMITHSONIAN JI Smithsonian PD JUN PY 1998 VL 29 IS 3 BP 10 EP 10 PG 1 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA ZQ071 UT WOS:000073818500001 ER PT J AU Mackay, DH Priest, ER Gaizauskas, V Van Ballegooijen, AA AF Mackay, DH Priest, ER Gaizauskas, V Van Ballegooijen, AA TI Role of helicity in the formation of intermediate filaments SO SOLAR PHYSICS LA English DT Article ID ACTIVE REGIONS; SOLAR PROMINENCES; MAGNETIC HELICITY; FIELD; MODEL AB In the last few years new observations have shown that solar filaments and filament channels have a surprising hemispheric pattern. To explain this pattern, a new theory for filament channel and filament formation is put forward. The theory describes the formation of a specific type of filament, namely the 'intermediate filament' which forms either between active regions or at the boundary of an active region. It describes the formation in terms of the emergence of a sheared activity complex. The complex then interacts with remnant flux and, after convergence and flux cancellation, the filament forms in the channel. A key feature of the model is the net magnetic helicity of the complex. With the correct sign a filament channel can form, but with the opposite sign no filament channel forms after convergence. It is shown how the hemispheric pattern of helicity in emerging flux regions produces the observed hemispheric pattern for filaments. C1 Univ St Andrews, Sch Math Sci, St Andrews KY16 9SS, Fife, Scotland. Natl Res Council Canada, Herzberg Inst Astrophys, Ottawa, ON K1A 0R6, Canada. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mackay, DH (reprint author), Univ St Andrews, Sch Math Sci, St Andrews KY16 9SS, Fife, Scotland. NR 27 TC 24 Z9 24 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 JUN PY 1998 VL 180 IS 1-2 BP 299 EP 312 DI 10.1023/A:1005028930121 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 103CK UT WOS:000074963700018 ER PT J AU Christen, C Herculano, S Hochstetler, K Prell, R Price, M Roberts, JT AF Christen, C Herculano, S Hochstetler, K Prell, R Price, M Roberts, JT TI Latin American environmentalism: Comparative views SO STUDIES IN COMPARATIVE INTERNATIONAL DEVELOPMENT LA English DT Article AB This article examines three common generalizations from the literature on Latin American environmentalism. The validity of these generalizations, structured as hypotheses, is tested with four case studies from Costa Pica, Mexico, Venezuela, and Brazil. The first generalization is that tensions arise between international environmentalists principally concerned with wildlands conservation and national environmentalists engaged in a broader array of local and domestic issues including urban environmental quality and access to natural resources. The second is that environmental groups in Latin America are elitist in structure and participant base. The third is that the particular tactics employed by environmentalists will be closely tied to the relative openness of their nation's political system. Through a cross-disciplinary case study approach we find the first two hypotheses quickly break down upon closer inspection, while the third is supported. We suggest a modified framework for interpreting environmental activism in the region, one that weighs the role of the state as well as the competing strategies employed by grassroots, private voluntary, and professionalized environmental groups. Latin American environmentalism is highly diverse, presenting many faces in different time periods and different countries. Developing one general theory of environmentalism in Latin America is impossible, but more specific categorizations of the middle range may be achievable. C1 Smithsonian Inst, Washington, DC 20560 USA. Univ Fed Fluminense, Dept Sociol, UFF, ICHF,GSO, BR-21940320 Niteroi, RJ, Brazil. Colorado State Univ, Dept Polit Sci, Ft Collins, CO 80523 USA. Univ Wisconsin, Dept Geog, Whitewater, WI 53190 USA. George Washington Univ, Dept Geog, Washington, DC 20052 USA. Tulane Univ, Program Latin Amer Studies, Dept Sociol, New Orleans, LA 70118 USA. RP Christen, C (reprint author), Smithsonian Inst, MRC 429, Washington, DC 20560 USA. RI Hochstetler, Kathryn/K-8482-2012; OI Hochstetler, Kathryn/0000-0003-2960-058X NR 65 TC 14 Z9 15 U1 0 U2 3 PU TRANSACTION PERIOD CONSORTIUM PI PISCATAWAY PA DEPT 4010, RUTGERS UNIV, 35 BERRUE CIRCLE, PISCATAWAY, NJ 08854-8042 USA SN 0039-3606 J9 STUD COMP INT DEV JI Stud. Comp. Int. Dev. PD SUM PY 1998 VL 33 IS 2 BP 58 EP 87 DI 10.1007/BF02687408 PG 30 WC International Relations; Planning & Development; Political Science SC International Relations; Public Administration; Government & Law GA 183HQ UT WOS:000079548500003 ER PT J AU Telford, SR Jennions, MD AF Telford, SR Jennions, MD TI Establishing cryptic female choice in animals SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Editorial Material ID YELLOW DUNG FLIES; SPERM COMPETITION; SCATOPHAGA-STERCORARIA; PRECEDENCE; HOMOGAMY C1 Smithsonian Trop Res Inst, Balboa, Panama. Unit 0948, APO, AA 34002 USA. RP Telford, SR (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. RI Jennions, Michael/C-7560-2009 OI Jennions, Michael/0000-0001-9221-2788 NR 15 TC 32 Z9 32 U1 0 U2 12 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD JUN PY 1998 VL 13 IS 6 BP 216 EP 218 DI 10.1016/S0169-5347(98)01372-X PG 3 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA ZQ354 UT WOS:000073852800003 PM 21238272 ER PT J AU Meggers, BJ AF Meggers, BJ TI Mate copying and cultural inheritance SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Letter ID EVOLUTION C1 Smithsonian Inst, Washington, DC 20560 USA. RP Meggers, BJ (reprint author), Smithsonian Inst, MRC-112, Washington, DC 20560 USA. RI Davidson, Iain/A-9216-2011 NR 10 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD JUN PY 1998 VL 13 IS 6 BP 240 EP 240 DI 10.1016/S0169-5347(98)01387-1 PG 1 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA ZQ354 UT WOS:000073852800010 PM 21238279 ER PT J AU Balakrishnan, N Dalgarno, A Billing, GD AF Balakrishnan, N Dalgarno, A Billing, GD TI Multiquantum vibrational transitions in O-2(nu >= 25)+O-2(nu=0) collisions SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SEMICLASSICAL WAVE-PACKET; STATE RATE CONSTANTS; ENERGY-TRANSFER; REACTION OH+H-2->H2O+H; MOLECULES; RELAXATION; OXYGEN; PHOTODISSOCIATION; MECHANISM; O-3 AB The quenching of highly vibrationally excited O-2 in collision with O-2(v = 0) is investigated using a semiclassical wave packet method. We find that nonreactive collisions dominate the relaxation of O-2(v) and for v in the range 25 to 30 the reactive channel makes little contribution to the quenching process, in agreement with our earlier investigation. We report vibrational transition cross sections and relaxation rate coefficients for v = 25 to 30 of the excited O-2(v) molecule. Our study shows that a multiquantum process involving a 2 --> 1 vibrational transition which has not been included in previous calculations makes an important contribution to the rate coefficients for the relaxation of O-2 vibrational levels v greater than or equal to 27. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Univ Copenhagen, HC Orsted Inst, Dept Chem, DK-2100 Copenhagen O, Denmark. RP Balakrishnan, N (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 23 TC 24 Z9 24 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 29 PY 1998 VL 288 IS 5-6 BP 657 EP 662 DI 10.1016/S0009-2614(98)00347-9 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZV253 UT WOS:000074285700010 ER PT J AU Frey, MA Lonsdale, DJ Snell, TW AF Frey, MA Lonsdale, DJ Snell, TW TI The influence of contact chemical signals on mate recognition in a harpacticoid copepod SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE chemical communication; Copepoda; glycoprotein; lectin; mate recognition ID BRACHIONUS-PLICATILIS; SIZE; POPULATIONS; PHEROMONE; ROTIFER AB Among copepods, reproduction is facilitated by a combination of sensory modalities, such as mechano-and chemoreception. The role of chemical communication in copepod mate recognition was assessed using behavioural bioassays that were based on precopulatory behaviours of an estuarine harpacticoid, Coullana canadensis, and the sibling species Coullana sp. Intra-and interspecific crosses demonstrated that males recognize genetically distinct conspecific and heterospecific females, indicating that prezygotic isolation remains incomplete. There was no association between the frequency of mate-guarding behaviour and geographic distance between populations of C. canadensis. However, reduced levels of interspecific mate guarding relative to intraspecific frequencies suggest the existence of a species-specific mate-recognition system. Lectins, which possess strong affinities for specific carbohydrate groups, were used to confirm that glycoproteins on the surface of females function as mate-recognition factors. Information regarding the chemical composition of these molecules was derived from observed effects of lectin binding to females on male mate-guarding behaviour. Mate guarding was inhibited within all tested populations when treated with Triticum vulgaris, a lectin that possesses an affinity for carbohydrates of the N-acetylglucosamine group. Surface glycoproteins responsible for mate recognition in the two species of Coullana may be glycosylated with monosaccharides from this group. Differential responses to lectin treatments suggested that composition of the contact chemical cues vary among populations of C. canadensis and between species. Yet, populations that appeared most similar based on shared lectin responses successfully discriminated against each other in mate-selection experiments. These findings indicate that contact chemical cues probably act in concert with additional factors to promote effective mate recognition and thereby contribute to reproductive success. C1 SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Georgia Inst Technol, Sch Biol, Atlanta, GA 30332 USA. RP Frey, MA (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. NR 33 TC 21 Z9 21 U1 0 U2 4 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8436 EI 1471-2970 J9 PHILOS T R SOC B JI Philos. Trans. R. Soc. B-Biol. Sci. PD MAY 29 PY 1998 VL 353 IS 1369 BP 745 EP 751 DI 10.1098/rstb.1998.0240 PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZU048 UT WOS:000074156000009 ER PT J AU Imamura, H Knapp, LW AF Imamura, H Knapp, LW TI Review of the genus Bembras Cuvier, 1829 (Scorpaeniformes : Bembridae) with description of three new species collected from Australia and Indonesia SO ICHTHYOLOGICAL RESEARCH LA English DT Review DE review; Bembras macrolepis sp. nov.; Bembras longipinnis sp. nov.; Bembras megacephala sp. nov. ID PLATYCEPHALIDAE; TELEOSTEI AB The bembrid genus Bembras Cuvier is reviewed. Five species, B. japonica Cuvier, B. adenensis Imamura & Knapp and three undescribed species, were assigned to the genus. Type species of the genus, Bembras japonica is redescribed on the basis of 36 specimens including the holotype, and three new species, B. macrolepis, B. longipinnis and B. megacephala, previously misidentified as B. japonicus, are also described on the basis of specimens collected from Australia and Indonesia. Bembras macrolepis differs from its congeners by having large body scales, a long pectoral fin with 17-19 rays and a dark blotch on slightly upper portion to middle of margin, 14-15 anal-fin rays, small head and orbit, and caudal fin with a broad vertical dark band near posterior margin. Bembras longipinnis is distinguished from other members of the genus by having a slightly long pectoral fin with 17-19 rays and lacking a small black blotch near tip of upper rays, caudal fin with a large dark spot most intense in lower lobe, 1-2 gill rakers on upper gill arch, 13-14 anal-fin rays, slightly elong ated head and small orbit. Bembras megacephala is characterized by the following combination of characters: caudal fin with several irregular narrow vertical dark bands, small orbit, pectoral fin with 19-20 rays and lacking a small black blotch near tip of upper rays, head elongate, 2-4, gill rakers on upper gill arch, 15 anal-fin rays and small body scales. A key separating the five species of Bembras is given. C1 Tohoku Natl Fisheries Res Inst, Fisheries Agcy, Hachinohe Branch, Hachinohe, Aomori 0310841, Japan. Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20560 USA. RP Imamura, H (reprint author), Tohoku Natl Fisheries Res Inst, Fisheries Agcy, Hachinohe Branch, 25-259 Same, Hachinohe, Aomori 0310841, Japan. EM hima@myg.affrc.go.jp; knapp.leslie@mnhm.si.edu NR 30 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER JAPAN KK PI TOKYO PA CHIYODA FIRST BLDG EAST, 3-8-1 NISHI-KANDA, CHIYODA-KU, TOKYO, 101-0065, JAPAN SN 1341-8998 J9 ICHTHYOL RES JI Ichthyol. Res. PD MAY 25 PY 1998 VL 45 IS 2 BP 165 EP 178 DI 10.1007/BF02678559 PG 14 WC Zoology SC Zoology GA ZZ275 UT WOS:000074713100007 ER PT J AU Olive, JF Barret, D Boirin, L Grindlay, JE Swank, JH Smale, AP AF Olive, JF Barret, D Boirin, L Grindlay, JE Swank, JH Smale, AP TI RXTE observation of the x-ray burster 1E 1724-3045 - I. Timing study of the persistent x-ray emission with the PCA SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : individual : 1E 1724-3045; globular clusters : individual : Terzan 2; X-rays : bursts; X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; APERIODIC VARIABILITY; BINARIES; STARS; STATE AB We report on the Rossi X-ray Timing Explorer Proportional Counter Array (PCA) observation of the X-ray burster 1E1724-3045 located in the globular cluster Terzan 2. The observation lasted for about 100 kiloseconds and spanned from November 4th to 8th, 1996. The PCA source count rate in the 2-20 keV range was about 470 cts/s. No large spectral variations were observed within our observation as inferred from color-color and hardness-intensity diagram analysis. The persistent tent X-ray emission shows a high level of noise variability, the so-called High Frequency Noise (HFN) with a fractional Root Mean Squared (RMS) of similar to 25% in the 2 x 10(-3) - 40 Hz range. The strong HFN together with the hardness of its X-ray spectrum suggest that 1E1724-3045 is an "Atoll" source which was in its "Island" slate during the observation. The Fourier Power Density Spectra (PDS) can be modeled in terms of the sum of two "shot noise" components for which the shots have a single-side exponential shape (i.e. instantaneous rise and exponential decay). The characteristic shot decay timescales inferred from the best fitting of the PDS are similar to 680 and 16 msec respectively. The two components contribute similarly to the total RMS (similar to 15%). The PDS contains also a third component: a broad and asymmetric peaked noise feature centered at 0.8 Hz. This Quasi Periodic Oscillation-like (QPO) feature contributes at the level of similar to 10% to the total RMS. Neither the shot timescales nor the QPO frequency vary with energy. On the other hand, the integrated RMS of all three components shows a positive correlation with energy up to at least 40 keV. Ln addition, in the 2-20 keV energy band where the signal to noise ratio is the highest, we found evidence for a high frequency component which shows up in the PDS above 100 Hz. In terms of the shot noise model, a Lorentzian fit of this last component implies a shot decay timescale of similar to 1.4 ms. We also show that 1E1724-3045 has striking timing similarities with the black hole candidate GROJ0422+32 (Nova Persei 1992). Our observation demonstrates that a low frequency QPO simultaneously with a high level of RMS is not a timing signature unique to black holes. This extends the growing list of similarities between Atoll sources and black hole systems. C1 CNRS, UPS, Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 04, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Barret, D (reprint author), CNRS, UPS, Ctr Etud Spatiale Rayonnements, 9 Ave Colonel Roche, F-31028 Toulouse 04, France. RI Swank, Jean/F-2693-2012 NR 38 TC 44 Z9 44 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 20 PY 1998 VL 333 IS 3 BP 942 EP 951 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZR231 UT WOS:000073953400024 ER PT J AU Zhang, XL AF Zhang, XL TI Secular evolution of spiral galaxies. II. Formation of quasi-stationary spiral modes SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, evolution; galaxies, kinematics and dynamics; galaxies, spiral; galaxies, structures ID DENSITY WAVES; MODAL APPROACH; DISSIPATION; MORPHOLOGY; SYSTEMS AB In this second of a series of three papers, we demonstrate that the kind of spiral patterns in disk galaxies which can remain quasi-stationary on the timescale of a Hubble time are spontaneously formed spiral modes. The amplitude of the spiral mode is limited to a finite value, determined by the basic state characteristics, through a collective dissipation process, introduced in Paper I of this series. We show that the radial distribution of the total torque coupling integral of a spontaneously formed spiral mode must be (and is found to be) of a characteristic bell shape, with the peak of the bell located at the corotation radius of the mode. This distribution of the total torque coupling is concordant with the radial distribution of the phase shift between the potential and density spirals (Paper I). Whereas the existence and the sign of the total torque coupling imply that there is angular momentum being carried outward by a trailing spiral density wave mode, the bell shape further indicates that there is angular momentum being deposited on each annular ring of the galactic disk en route of this outward angular momentum transport. The amount of the deposited angular momentum is negative inside corotation and is positive outside corotation. Since a spiral mode has negative angular momentum density inside corotation and positive angular momentum density outside corotation, it follows that the bell-shaped torque coupling of a trailing spiral model leads to its own spontaneous growth in the linear regime. In going from the linear to the progressively nonlinear regimes, an increasingly larger fraction of the deposited angular momentum is channeled onto the basic state of the disk through a collisionless shock, rather than being used entirely for the wave mode growth. Finally, in the fully nonlinear regime (the quasisteady state of the wave mode), all of the angular momentum deposited by the trailing spiral mode is given to the basic state. The spiral mode can then remain quasi-stationary on the order of a Hubble time, at the expense of a continuous dissipative basic state evolution. It is argued that the spontaneous formation and stabilization of a large-scale spiral mode in a disk galaxy is an example of a nonequilibrium phase transition. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Zhang, XL (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,Mail Stop 78, Cambridge, MA 02138 USA. NR 42 TC 34 Z9 34 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP 93 EP 111 DI 10.1086/305595 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ838 UT WOS:000073908100007 ER PT J AU Harrus, IM Hughes, JP Slane, PO AF Harrus, IM Hughes, JP Slane, PO TI Study of the composite supernova remnant MSH 11-62 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, individual (MSH 11-62); radiation mechanisms, nonthermal; supernova remnants; X-rays, ISM ID NEBULA; EVOLUTION; PULSARS; CATALOG AB We present the analysis of the X-ray data collected during an observation of the supernova remnant (SNR) MSH 11-62 by the Advanced Satellite for Cosmology and Astrophysics (ASCA). We show that MSH 11-62 is a composite remnant whose X-ray emission comes from two distinct contributions. Nonthermal, synchrotron emission, localized to a region of radius similar to 3' (consistent with a point source), dominates the total flux above 2 keV. A second contribution comes from a thermal component, extended up to a radius of similar to 6' and detected only at energies below 2 keV. The spatial and spectral analyses imply the presence of a neutron star losing energy at a rate of about (E) over dot similar to 10(36) - 10(37) ergs s(-1). No pulsed emission is detected, and we set a limit on the pulsed fraction of similar to 10%. This is consistent with the lack of a radio pulsar in the remnant, which may indicate that the pulsed emission from the rapidly rotating compact object that should be powering the synchrotron nebula is beamed, and our viewing direction is unfavorable. In either event, the central neutron star deposits much of its spin-down energy into the surrounding synchrotron nebula where, through direct imaging with broadband satellites such as ASCA, it is possible to study the energetics and evolution of the compact remnant. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. RP Harrus, IM (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 28 TC 14 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP 273 EP 281 DI 10.1086/305634 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ838 UT WOS:000073908100024 ER PT J AU Orosz, JA Jain, RK Bailyn, CD McClintock, JE Remillard, RA AF Orosz, JA Jain, RK Bailyn, CD McClintock, JE Remillard, RA TI Orbital parameters for the soft X-ray transient 4U 1543-47: Evidence for a black hole SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, spectroscopic; black hole physics; stars, individual (4U 1543-47); X-rays, stars ID SPECTROSCOPY; A0620-00; MASS AB Spectroscopic observations of the soft X-ray transient 4U 1543-47 reveal a radial velocity curve with a period of P = 1.123 +/- 0.008 days and a semiamplitude of K-2 = 124 +/- 4 km s(-1). The resulting mass function is f(M) = 0.22 +/- 0.02 M.. We classify the secondary star as A2 V, in agreement with previous work, and measure T-eff = 9000 +/- 500 K and E(B-V) = 0.50 +/- 0.05 from fits to synthetic spectra. We derive a distance of d = 9.1 +/- 1.1 kpc if the secondary is on the main sequence. We see no emission lines from the accretion disk, and the measured fractions of disk light in the B- and V-bands are 10% and 21%, respectively. The V and I light curves exhibit two Waves per orbital cycle with amplitudes approximate to 0.08 mag. We model the light curves as ellipsoidal variations in the secondary star and derive extreme inclination limits of 20 degrees less than or equal to i less than or equal to 40 degrees. The formal 3 sigma limits on the inclination from a simultaneous fit to the V and I light curves are 24 degrees less than or equal to i less than or equal to 36 degrees for a mass ratio Q = M-1/M-2 greater than or equal to 1. However, there are systematic effects in the data that the model does not account for, so the above constraints should be treated with caution. We argue that the secondary star is still on the main sequence with the mass transfer being driven by expansion due to normal main sequence evolution. If the secondary star has a mass near the main sequence values for early A stars (2.3 less than or equal to M-2 less than or equal to 2.6 M.), then the best fits for the 3 sigma inclination range (24 degrees less than or equal to i less than or equal to 36 degrees) and the 3 sigma mass function range (0.16 less than or equal to f(M) less than or equal to 0.28 M.) imply a primary mass in the range 2.7 less than or equal to M-1 less than or equal to 7.5 M.. The mass of the compact object in 4U 1543-47 is likely to be in excess of approximate to 3 M., which is widely regarded as the maximum mass of a stable neutron star. Thus we conclude that 4U 1543-47 most likely contains a black hole. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. RP Orosz, JA (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. EM orosz@astro.psu.edu; raj.jain@yale.edu; bailyn@astro.yale.edu; jem@cfa.harvard.edu; rr@space.mit.edu NR 53 TC 68 Z9 68 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP 375 EP 384 DI 10.1086/305620 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ838 UT WOS:000073908100035 ER PT J AU Kaitchuck, RH Schlegel, EM White, JC Mansperger, CS AF Kaitchuck, RH Schlegel, EM White, JC Mansperger, CS TI Spectroscopy of the cataclysmic variable UU Aquartii: s-waves and bright spots SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries, eclipsing; novae, cataclysmic variables; stars, individual (UU Aquarii); stars, spots ID TIME-RESOLVED SPECTROPHOTOMETRY; MULTICOLOR ECLIPSE; TOMOGRAPHY AB This paper reports the results of UV and optical spectroscopy of the nova-like variable UV Aqr. There is a decrease in the light flux of both the optical and UV emission lines at phase similar to 0.95. This appears to be due to an occultation of an asymmetric accretion disk. The emission-line profiles seem to show the first half of the rotational disturbance of the disk eclipse. There is a secondary eclipse at phase 0.4 in the optical continuum and the hydrogen emission lines. It is not present in the UV continuum or emission lines. This eclipse occurs when the bright spot is at superior conjunction. This raises the possibility that this is an occultation of the bright spot/s-wave region by material suspended above the central disk. The accretion disk emission in the Doppler tomogram of the HP emission line was used to obtain the radial velocity amplitude of the white dwarf star. The mass ratio was estimated by matching the s-wave position with stream trajectories. The results were significantly different from that of Baptista et al. These authors used the eclipse phasing of the continuum hot spot and the assumption that the hot spot is located on the stream trajectory. The reasons for this discrepancy are unclear. C1 Ball State Univ, Dept Phys & Astron, Muncie, IN 47304 USA. Smithsonian Astrophys Observ, High Energy Astrophys Div, Cambridge, MA 02138 USA. Middle Tennessee State Univ, Dept Phys & Astron, Murfreesboro, TN 37132 USA. Photon Res Associate, Arlington, VA 22209 USA. RP Kaitchuck, RH (reprint author), Ball State Univ, Dept Phys & Astron, Muncie, IN 47304 USA. EM 00rhkaitchuc@bsuvc.bsu.edu; esch1egel@cfa.harvard.edu; jcwhite@mtsu.edu; mansperger@iue.gsfc.nasa.gov NR 22 TC 4 Z9 4 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP 444 EP 453 DI 10.1086/305610 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ838 UT WOS:000073908100042 ER PT J AU Arce, HG Goodman, AA Bastien, P Manset, N Sumner, M AF Arce, HG Goodman, AA Bastien, P Manset, N Sumner, M TI The polarizing power of the interstellar medium in Taurus SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; ISM, clouds; ISM, magnetic fields; polarization ID DARK CLOUD; INFRARED POLARIMETRY; MAGNETIC-FIELD; EXTINCTION; GRAIN AB We present a study of the polarizing power of dust in cold dense regions (dark clouds) compared with that of dust in the general interstellar medium (ISM), Our study uses new polarimetric, optical, and spectral classification data for 36 stars to carefully study the relation between polarization percentage (p) and extinction (A(v)) in the Taurus dark cloud complex. We find two trends in our p-A(v) study: (1) stars that are background to the warm ISM show an increase in p with A(v), and (2) the percentage nf polarization of stars that are background to cold dark clouds does not increase with extinction. We detect a break in the p-A(v) relation at nrl exttlzctiooz of 1.3 +/- 0.2 mag, which we expect corresponds to a set of conditions where the polarizing power of the dust associated with the Taurus dark clouds drops precipitously. This break point places important restrictions on the use of polarimetry in studying interstellar magnetic fields. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Sci Fdn, Washington, DC USA. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Observ Mt Megant, Montreal, PQ H3C 3J7, Canada. 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 28 TC 47 Z9 47 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1998 VL 499 IS 1 BP L93 EP + DI 10.1086/311337 PN 2 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ839 UT WOS:000073908200022 ER PT J AU Bukowski, R Jeziorski, B Szalewicz, K AF Bukowski, R Jeziorski, B Szalewicz, K TI Analytic first-order properties from explicitly correlated many-body perturbation theory and Gaussian geminal basis SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR CORRELATION ENERGIES; ELECTRON CORRELATION; BASIS-SETS; HYDROGEN MOLECULE; GROUND-STATE; VARIATIONAL CALCULATIONS; WAVE-FUNCTION; HELIUM DIMER; H-2; LIH AB Theory of analytic first-order properties is formulated in a basis set independent way using the first-quantized many-body perturbation theory. This formulation allows the correlation effects to be described with explicitly correlated basis sets. The basis of Gaussian geminals is employed to calculate the second-and third-order correlation corrections to the lowest multipole moments of the H-2 and LiH molecules. The same formalism is also utilized to compute the intra-atomic correlation contribution to the first-order interaction energy for the helium dimer. The results compare favorably with the literature data obtained using the conventional, orbital basis approach. (C) 1998 American Institute of Physics. C1 Univ Warsaw, Dept Chem, Quantum Chem Lab, PL-02093 Warsaw, Poland. Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Bukowski, R (reprint author), Univ Warsaw, Dept Chem, Quantum Chem Lab, Pasteura 1, PL-02093 Warsaw, Poland. NR 60 TC 11 Z9 11 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 1998 VL 108 IS 19 BP 7946 EP 7958 DI 10.1063/1.476235 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZM675 UT WOS:000073564600003 ER PT J AU Sarazin, CL Wise, MW Markevitch, ML AF Sarazin, CL Wise, MW Markevitch, ML TI X-ray spectral properties of the cluster Abell 2029 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cooling flows; galaxies, clusters, general; galaxies, clusters, individual (A2029); galaxies, elliptical and lenticular, cD; intergalactic medium; X-rays, galaxies ID COOLING FLOWS; ABSORBING MATTER; GALAXIES; CATALOG AB We have analyzed ASCA and ROSAT PSPC spectra and images of the galaxy cluster Abell 2029. The ASCA spectra of the cluster indicate that the gas temperature declines with radius. The PSPC image shows that the cluster is very regular and smooth. Also, there is no significant evidence for any irregularities in the temperature distribution in the cluster, as would be produced by a subcluster merger. These results suggest that A2029 is a relaxed cluster and that the gas is in hydrostatic equilibrium. We use the assumption of equilibrium to determine the gravitational mass of the cluster as a function of radius. At a radius of 16' (1.92 h(50)(-1) Mpc; H-0 = 50 h(50) km s(-1) Mpc(-1)), the gravitational mass is M-tot = (9.42 +/- 4.22) x 10(14) h(50)(-1) M., while the mass of gas is M-gas = (2.52 +/- 0.77) x 10(14) h(50)(-5/2) M.. The gas fraction is found to increase with radius; within a spherical radius of 16', the fraction is M-gas/M-tot = (0.26 +/- 0.14) h(50)(-3/2). The iron abundance in the gas is found to be 0.40 +/- 0.04 solar. There is no significant evidence for any variation in the abundance with position in the cluster. The global X-ray spectra, central X-ray spectra, and ROSAT surface brightness all require a cooling flow at the cluster center. The global X-ray spectrum implies that the total cooling rate is 363(-96)(+79) h(50)(-2) M. yr(-1). The global X-ray spectra are consistent with the Galactic value for the soft X-ray absorption toward the cluster. White et al. and Alien & Fabian have suggested that there is significant excess absorption associated with the cooling flow in the cluster. The ROSAT PSPC spectra of the central regions of the cluster are inconsistent with a large value of foreground excess absorption. The upper limit on excess foreground absorption is 7.3 x 10(19) cm(-2). However, the spectra do not rule out a significant amount of intrinsic absorbing gas located within the cooling flow region. C1 Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Sarazin, CL (reprint author), Univ Virginia, Dept Astron, POB 3818, Charlottesville, VA 22903 USA. NR 31 TC 34 Z9 34 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1998 VL 498 IS 2 BP 606 EP 618 DI 10.1086/305578 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZN664 UT WOS:000073669300008 ER PT J AU Saar, SH Butler, RP Marcy, GW AF Saar, SH Butler, RP Marcy, GW TI Magnetic activity-related radial velocity variations in cool stars: First results from the Lick extrasolar planet survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE convection; stars, activity; stars, late-type; stars, planetary systems; stars, spots; techniques, radial velocities ID MAIN-SEQUENCE STARS; SOLAR-TYPE STARS; ROTATION; DWARFS AB The discovery of the radial velocity (v(r)) signatures of planets around several solar-like stars highlights the importance of exploring the sources of v(r). variations intrinsic to the stars themselves. We study the stars in the Lick planetary survey for v(r) variations related to stellar activity: the rotation of starspots and convective inhomogeneities and their temporal evolution. We study the relationships between the weighted v(r) dispersion, sigma(v)' (which has first been corrected for the orbital contribution from known planets and the mean internal error), and spectral type, rotation, and activity (as measured by Ca II H and K). We find that the largest sigma(v)' values occur among both the coolest (dMe) and the warmest (active F) stars. Values of sigma(v)' increase with H and K emission and scale proportional to v sin i in G and K stars and proportional to (v sin i)(1.3) in F stars. For a G star with zi sin i approximate to 8-10 km s(-1) (age similar to 0.3 Gyr), for example, 20 m s(-1) less than or similar to sigma(v)' less than or similar to 45 m s(-1), roughly consistent with the predicted sigma(v)' levels due to magnetic activity (Saar & Donahue). All the stars with proposed planetary companions show sigma(v)' values typical for their spectral type, activity, and/or rotation. However, before the planetary v(r) perturbations are removed, these stars show significantly enhanced sigma(v)' values. We develop a simple model that can predict the sigma(v)' expected for a given star (within approximate to 40%) as a function of v sin i, spectral type, photometric variability, and macroturbulent velocity. The implications for extrasolar planet searches are discussed. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94132 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Saar, SH (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM ssaar@cfa.harvard.edu; paul@aaossz.aao.gov.au; gmarcy@etoile.berkeley.edu RI Butler, Robert/B-1125-2009 NR 40 TC 190 Z9 190 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1998 VL 498 IS 2 BP L153 EP L157 DI 10.1086/311325 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZN687 UT WOS:000073671600013 ER PT J AU Mazeh, T Latham, DW Stefanik, P AF Mazeh, T Latham, DW Stefanik, P TI Radial velocity search for low mass companions of nearby stars SO ACTA ASTRONAUTICA LA English DT Article ID SOLAR-TYPE STARS; SUBSTELLAR COMPANIONS; SPECTROSCOPIC BINARIES; RATIO DISTRIBUTION; BROWN DWARFS; SYSTEM; LONG AB The detection of substellar companions of nearby stars is very difficult, because these objects are very faint and are located close to their bright parent stars. One way to attack this problem is to look for small periodic motion of the bright star, induced by the gravitational attraction exerted by the unseen small companion. Over the past decade stellar spectroscopy has been used by a few teams to monitor the radial velocities of several samples of stars, with a threshold for detection of companions well below the substellar limit of about 0.08 M.. So far, only a few possible spectroscopic binaries have been identified where the unseen companions might be substellar. Recently, radio observers discovered that the millisecond pulsar PSR B1257 + 12 displays periodic variations in the pulse arrival times, indicating the existence of at least three unseen companions in circular orbits around the pulsar. This is the first convincing case for an extra-solar planetary system. This discovery suggests that planetary systems can form in very different situations, and therefore may prove to be common. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 Smithsonian Inst, Natl Air & Space Museum, Astrophys Lab, Washington, DC 20560 USA. RP Mazeh, T (reprint author), Smithsonian Inst, Natl Air & Space Museum, Astrophys Lab, Washington, DC 20560 USA. NR 31 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 1998 VL 42 IS 10-12 BP 593 EP 598 DI 10.1016/S0094-5765(98)00013-7 PG 6 WC Engineering, Aerospace SC Engineering GA 116RT UT WOS:000075738900007 ER PT J AU Robinson, MH AF Robinson, MH TI Enriching the lives of zoo animals, and their welfare: Where research can be fundamental SO ANIMAL WELFARE LA English DT Article DE animal welfare; enrichment; exhibit design; research; zoos ID INEXTRICABLE CONNECTION; BEHAVIOR; MAINTENANCE; MOTIVATION; SEEKING; FOOD C1 Smithsonian Inst, Natl Zool Pk, Washington, DC 20008 USA. RP Robinson, MH (reprint author), Smithsonian Inst, Natl Zool Pk, Washington, DC 20008 USA. NR 93 TC 23 Z9 23 U1 9 U2 51 PU UNIV FEDERATION ANIMAL WELFARE PI WHEATHAMPSTEAD PA OLD SCHOOL, BREWHOUSE HILL, WHEATHAMPSTEAD, HERTS, ENGLAND AL4 8AN SN 0962-7286 J9 ANIM WELFARE JI Anim. Welf. PD MAY PY 1998 VL 7 IS 2 BP 151 EP 175 PG 25 WC Veterinary Sciences; Zoology SC Veterinary Sciences; Zoology GA ZK949 UT WOS:000073383800003 ER PT J AU Kane, MD Braun, WJ AF Kane, MD Braun, WJ TI Microbes in amber SO ASM NEWS LA English DT Letter ID DNA C1 Smithsonian Inst, Natl Museum Nat Hist, Lab Mol Systemat, Washington, DC 20560 USA. NR 12 TC 1 Z9 1 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0044-7897 J9 ASM NEWS JI ASM News PD MAY PY 1998 VL 64 IS 5 BP 250 EP 250 PG 1 WC Microbiology SC Microbiology GA ZM077 UT WOS:000073502400004 ER PT J AU Stanek, KZ Kaluzny, J Krockenberger, M Sasselov, DD Tonry, JL Mateo, M AF Stanek, KZ Kaluzny, J Krockenberger, M Sasselov, DD Tonry, JL Mateo, M TI Direct distances to nearby galaxies using detached eclipsing binaries and Cepheids. II. Variables in the field M31A SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries, eclipsing; Cepheids; distance scale; galaxies, individual (M31); stars, variables, other ID STARS AB We have undertaken a long-term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder-M31 and M33-using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, DEBs provide us with the potential to determine these distances with an accuracy better than 5%. The extensive photometry obtained in order to detect DEBs provides us with good light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries, the distance estimates will be free of any intermediate steps. As a first step in the DIRECT project, between 1996 September and 1997 January we obtained 36 full nights on the Michigan-Dartmouth-MIT Observatory 1.3 m telescope and 45 full/partial nights on the F. L. Whipple Observatory 1.2 m telescope to search for DEBs and new Cepheids in the M31 and M33 galaxies. In this paper, second in a series, we present the catalog of variable stars, most of them newly detected, found in the field M31A [(alpha, delta)=(11.degrees 34, 41.degrees 73), J2000.0]. We have found 75 variable stars: 15 eclipsing binaries, 43 Cepheids, and 17 other periodic, possible long-period or nonperiodic variables. The catalog of variables, as well as their photometry and finding charts, is available via anonymous ftp and the World Wide Web. The CCD frames are available upon request. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Warsaw Univ Observ, PL-00478 Warszawa, Poland. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. RP Stanek, KZ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,Mail Stop 20, Cambridge, MA 02138 USA. EM kstanek@cfa.harvard.edu; jka@sirius.astrouw.edu.pl; krocken@cfa.harvard.edu; sasselov@cfa.harvard.edu; jt@avidya.ifa.hawaii.edu; mateo@astro.lsa.umich.edu NR 28 TC 56 Z9 56 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1998 VL 115 IS 5 BP 1894 EP 1915 DI 10.1086/300342 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ213 UT WOS:000073834100014 ER PT J AU Gomez, M Whitney, BA Wood, K AF Gomez, M Whitney, BA Wood, K TI A survey of optical jets and Herbig-Haro objects in the p Ophiuchi cloud core SO ASTRONOMICAL JOURNAL LA English DT Article DE H II regions; ISM, individual (p Ophiuchi cloud); ISM, jets and flows ID YOUNG STELLAR OBJECTS; STAR-FORMING REGIONS; MAIN-SEQUENCE STARS; SPECTRAL ENERGY-DISTRIBUTIONS; NEAR-INFRARED OBSERVATIONS; X-RAY SOURCES; DARK CLOUD; STANDARD STARS; CLUSTER; TAURUS AB We describe a deep narrowband [S II] imaging survey of similar to 0.7 deg(2) covering the rho Ophiuchi cloud core (L1688). We detect seven new jet/Herbig-Haro (HH) objects in our survey, of which three are new detections and four confirm candidates from a recent survey by Wilking et al. Together with the five previously known objects, this brings the total to 12 known jet/HH objects in the cloud. In addition to this, we propose six new candidate HH objects. The most likely sources to power the new jet/HH objects appear to be optically visible stars; however, a conclusive association between the HH objects and pre-main-sequence stars is difficult, as several candidate driving sources lie in close vicinity of the new knots. Practically all of the HH objects are located on the perimeter of the cloud. The lack of optical emission toward the center of the cloud and the high spatial concentration of the youngest protostars toward the densest regions strongly suggest that jets inside the cloud are obscured from our view at optical wavelengths. A near-infrared H-2 survey is required to penetrate into the cloud and to study the outflow activity in this extremely active star-forming region. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Gomez, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM mgomez@cfa.harvard.edu; whitney@monte.neep.wisc.edu; kwood@cfa.harvard.edu NR 56 TC 23 Z9 23 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1998 VL 115 IS 5 BP 2018 EP 2027 DI 10.1086/300332 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ213 UT WOS:000073834100023 ER PT J AU Torres, G Neuhauser, R Wichmann, R AF Torres, G Neuhauser, R Wichmann, R TI BD +05(degrees)706: A new member of the class of "cool Algols" SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries, close; binaries, spectroscopic; stars, activity; stars, individual (BD + 05(degrees)706); stars, late-type ID RS-CANUM-VENATICORUM; T-TAURI STARS; ACTIVE BINARY-SYSTEMS; X-RAY-EMISSION; CA-II H; ECLIPSING BINARIES; RZ CANCRI; TEMPERATURES; COMPONENTS; MASSES AB We report the serendipitous discovery of an Algol-type binary with an orbital period of 18.9 days, in which both components are cool giants (G8 III and K1-K2 III). Few systems with these characteristics are known and are referred to as "cool Algols," as opposed to the "classical Algols" in which the mass-gaining component resembles an early-type main-sequence star. The nature of this object, which is a strong X-ray source, was discovered in the course of a spectroscopic search for T Tauri stars among ROSAT All-Sky Survey sources. We derive a double-lined spectroscopic orbit leading to minimum masses of M-A-2.481 +/- 0.023 M-circle dot and M-B = 0.515 +/- 0.011 M-circle dot and a corresponding mass ratio of q similar to 0.21. We measure also projected rotational velocities of 22 and 31 km s(-1), respectively, and a luminosity ratio of l(B)/l(B) = 1.06 +/- 0.04 at similar to 5200 Angstrom. The system is probably semidetached, with the axial spin of the components synchronized with the orbital motion, and the probability of eclipses is high. The general properties of BD +05 degrees 706, most likely a result of case B mass exchange, are very similar to those of the other known members of this class. We discuss the correlation between the mass of the hotter, detached components and their effective temperature for all cool Algols, noted previously by D. M. Popper, as well as a trend with the orbital period. Chromospheric activity indicators in ED +05 degrees 706 are compared with those of other members of its class, as well as with those of the classical Algols and the RS CVn binaries. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Interuniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India. Landessternwarte Konigstuhl, D-69117 Heidelberg, Germany. RP Torres, G (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM gtorres@cfa.harvard.edu; me@mpe-garching.mpg.de; rainer@iucaa.ernet.in NR 74 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1998 VL 115 IS 5 BP 2028 EP 2043 DI 10.1086/300329 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ213 UT WOS:000073834100024 ER PT J AU Briceno, C Hartmann, L Stauffer, J Martin, E AF Briceno, C Hartmann, L Stauffer, J Martin, E TI A search for very low mass pre-main-sequence stars in Taurus SO ASTRONOMICAL JOURNAL LA English DT Article DE stars, evolution; stars, formation; stars, low-mass, brown dwarfs ID SOLAR NEIGHBORHOOD; SPECTRAL SEQUENCE; EXTINCTION LAW; DWARFS; AURIGA; TEMPERATURE; PHOTOMETRY; EMISSION; MICRONS; MODELS AB We present the initial results of a deep CCD survey for very low mass pre-main-sequence (PMS) stars in selected fields of the Taurus molecular cloud complex. The results reported herein span a little over half a square degree in the dark clouds L1495, L1529, L1551, and B209. Our survey is complete down to I-C similar to 19 at (R-I)(C) similar to 2.5, which enables us to probe well below the hydrogen burning limit at 1-2 Myr. From follow-up spectroscopic observations we have identified nine new low-mass T Tauri stars (TTSs). A large fraction of the new PMS objects (5/9) have very low masses as inferred from their late spectral types (greater than or equal to M5), and comparison with recent evolutionary tracks and Pleiades brown dwarfs suggests that our M6-M6.5 new TTSs are very young brown dwarfs. Two of the new TTSs may constitute a new, moderately embedded, binary classical T Tauri system. The new young stars represent a similar to 38% increase in the known PMS population of our survey area and a factor of similar to 2 increase in the number of known late-type TTSs. In spite of our sensitivity, we detect no young stars with spectral types later than similar to M7. Our results illustrate the importance of spectroscopy in eliminating foreground M stars. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Ctr Invest Astron, CIDA, Merida, Venezuela. Cent Univ Venezuela, Caracas, Venezuela. Inst Astrofis Canarias, La Laguna 38200, Tenerife, Spain. RP Briceno, C (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 56 TC 142 Z9 142 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1998 VL 115 IS 5 BP 2074 EP 2091 DI 10.1086/300338 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ213 UT WOS:000073834100029 ER PT J AU Kenyon, SJ Luu, JX AF Kenyon, SJ Luu, JX TI Accretion in the early Kuiper Belt. I. Coagulation and velocity evolution SO ASTRONOMICAL JOURNAL LA English DT Article DE Kuiper belt objects ID PRIMORDIAL SOLAR NEBULA; N-BODY SIMULATION; PLANETESIMAL ACCUMULATION; TIME SCALES; GRAVITATIONAL INTERACTION; PROTOPLANETARY CLOUD; NUMERICAL-SIMULATION; PLANETARY SYSTEMS; DYNAMIC FRICTION; RUNAWAY GROWTH AB We describe planetesimal accretion calculations in the Kuiper Belt. Our evolution code simulates planetesimal growth in a single annulus and includes velocity evolution but not fragmentation. Test results match analytic solutions and duplicate previous simulations at 1 AU. In the Kuiper Belt, simulations without velocity evolution produce a single runaway body with a radius r(i) greater than or similar to 1000 km on a timescale tau(r) proportional to M(0)(-1)e(0)(x), where M(0) is the initial mass in the annulus, e(0) is the initial eccentricity of the planetesimals, and x approximate to 1-2. Runaway growth occurs in 100 Myr for M(0) approximate to 10M(E) and e(0) approximate to 10(-3) in a 6 AU annulus centered at 35 AU. This mass is close to the amount of dusty material expected in a minimum-mass solar nebula extrapolated into the Kuiper Belt. Simulations with velocity evolution produce runaway growth on a wide range of timescales. Dynamical friction and viscous stirring increase particle velocities in models with large (8 km radius) initial bodies. This velocity increase delays runaway growth by a factor of 2 compared with models without velocity evolution. In contrast, collisional damping dominates over dynamical friction and viscous stirring in models with small (80-800 m) initial bodies. Collisional damping decreases the timescale to runaway growth by factors of 4-10 relative to constant-velocity calculations. Simulations with minimum-mass solar nebulae, M(0) similar to 10M(E), and small eccentricities, e approximate to 10(-3), reach runaway growth on timescales of 20-40 Myr with 80 m initial bodies, 50-100 Myr with 800 m bodies, and 75-250 Myr for 8 km initial bodies. These growth times vary linearly with the mass of the annulus, tau(r), proportional to M(0)(-1), but are less sensitive to the initial eccentricity than constant-velocity models. In both sets of models, the timescales to produce 1000+ km objects are comparable to estimated formation timescales for Neptune. Thus, Pluto-sized objects can form in the outer solar system in parallel with the condensation of the outermost large planets. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Harvard Univ, Dept Astron, Cambridge, MA 02138 USA. RP Kenyon, SJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM skenyon@cfa.harvard.edu; jluu@cfa.harvard.edu OI Kenyon, Scott/0000-0003-0214-609X NR 77 TC 114 Z9 116 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 MAY PY 1998 VL 115 IS 5 BP 2136 EP 2160 DI 10.1086/300331 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ213 UT WOS:000073834100035 ER PT J AU Comastri, A Fiore, F Guainazzi, M Matt, G Stirpe, GM Zamorani, G Brandt, WN Leighly, KM Piro, L Molendi, S Parmar, AN Siemiginowska, A Puchnarewicz, EM AF Comastri, A Fiore, F Guainazzi, M Matt, G Stirpe, GM Zamorani, G Brandt, WN Leighly, KM Piro, L Molendi, S Parmar, AN Siemiginowska, A Puchnarewicz, EM TI BeppoSAX observations of narrow-line Seyfert 1 galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : galaxies; galaxies : Seyfert; galaxies : individual : Ton S 180 ID ACTIVE GALACTIC NUCLEI; X-RAY VARIABILITY; BLACK-HOLE; FE-II; SPECTRUM; ULTRAVIOLET; DISCOVERY; MODELS; DISKS; BUMP AB We report on the first spectrum up to 10 keV of the bright narrow-line Seyfert 1 galaxy Ton S 180, obtained with the imaging instruments onboard BeppoSAX. This is the first observed source in a sample of a dozen narrow-line Seyfert 1 galaxies in the BeppoSAX Core Program, We also present and discuss a high quality optical spectrum taken at the 1.5 m telescope at La Silla two months before the BeppoSAX observation. The X-ray spectrum shows a clear hardening above about 2 keV, where a power law with Gamma similar or equal to 2.3 plus an iron line provide a good description of the data. This slope is significantly steeper than the typical one for classical Seyfert 1's and quasars. The best fit line energy is suggestive of highly ionized iron, which would support the idea that the high accretion rate is (one of) the fundamental parameter(s) characterizing the Narrow Line Seyfert 1 phenomenon. C1 Osservatorio Astron Bologna, I-40126 Bologna, Italy. Osserv Astron Roma, I-00040 Monte Porzio Catone, Italy. Nuova Telespazio, Sci Data Ctr, SAX, I-00131 Rome, Italy. Univ Studi Roma Tre, Dipartimento Fis E Amaldi, I-00146 Rome, Italy. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. CNR, Ist Astrofis Spaziale, I-00044 Frascati, Italy. CNR, Ist Fis Cosm & Tecnol Relat, I-20133 Milan, Italy. European Space Agcy, Estec, Dept Space Sci, SA,Astrophys Div, NL-2200 AG Noordwijk, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Comastri, A (reprint author), Osservatorio Astron Bologna, Via Zamboni 33, I-40126 Bologna, Italy. EM comastri@astbo3.bo.astro.it RI PIRO, LUIGI/E-4954-2013; Brandt, William/N-2844-2015; Stirpe, Giovanna/O-9393-2015; Comastri, Andrea/O-9543-2015; OI PIRO, LUIGI/0000-0003-4159-3984; Brandt, William/0000-0002-0167-2453; Stirpe, Giovanna/0000-0002-3702-8731; Comastri, Andrea/0000-0003-3451-9970; Zamorani, Giovanni/0000-0002-2318-301X; Molendi, Silvano/0000-0002-2483-278X; Fiore, Fabrizio/0000-0002-4031-4157 NR 47 TC 56 Z9 57 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 1 PY 1998 VL 333 IS 1 BP 31 EP 37 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ375 UT WOS:000073854900010 ER PT J AU Pen, UL AF Pen, UL TI Normalizing the temperature function of clusters of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology, theory; galaxies, clusters, general; hydrodynamics; methods, numerical ID COLD DARK-MATTER; COSMOLOGICAL CONSTANT; ANISOTROPIES; STATISTICS; UNIVERSE; DENSITY; FIELDS; SAMPLE AB We reexamine the constraints that can be robustly obtained from the observed temperature function of X-ray studies of cluster of galaxies. The cluster mass function has been thoroughly and analytically studied in simulations, but a direct simulation of the temperature function is presented here for the first time. Adaptive hydrodynamic simulations using the cosmological Moving Mesh Hydro code are used to calibrate the temperature function for different popular cosmologies. Applying the new normalizations to the present-day cluster abundances, we find sigma(8) = 0.53 +/- 0.05 Ohm(0)(-0.45) for a hyperbolic universe and sigma(8) = 0.53 +/- 0.05 Ohm(0)(-0.53) for a spatially flat universe with a cosmological constant. The simulations followed the gravitational shock heating of the gas and dark matter and used a crude model for energy injection by supernova heating. The error bars are dominated by uncertainties in the heating/cooling models. We present fitting formulae for the mass-temperature conversions and cluster abundances based on these simulations. C1 Harvard Soc Fellows, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Pen, UL (reprint author), Harvard Soc Fellows, Cambridge, MA 02138 USA. NR 42 TC 87 Z9 87 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP 60 EP 66 DI 10.1086/305514 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100006 ER PT J AU Green, PJ AF Green, PJ TI Differences between the optical/ultraviolet spectra of X-ray bright and X-ray faint QSOs SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; quasars, emission lines; quasars, general; ultraviolet, galaxies; X-rays, galaxies ID ACTIVE GALACTIC NUCLEI; FE-II-EMISSION; RADIO-QUIET; QUASARS; CONTINUUM; GALAXIES; OBJECTS; EXCESS; LINES; LOUD AB We contrast measurements of composite optical and ultraviolet (UV) spectra constructed from samples of QSOs defined by their soft X-ray brightness. X-ray bright (XB) composites show stronger emission lines in general, but particularly from the narrow-line region. The difference in the [O III]/H beta ratio is particularly striking, and is even more so when blended Fe II emission is properly subtracted. The correlation of this ratio with X-ray brightness was a principal component of QSO spectral diversity found by Boroson & Green. We find here that other, much weaker narrow optical forbidden lines ([O II] and [Ne v]) are enhanced by factors of 2 to 3 in our XB composites, and that narrow line emission is also strongly enhanced in the XB UV composite. Broad permitted-line fluxes are slightly larger for all XB spectra, but the narrow-/broad-line ratio stays similar or increases strongly with X-ray brightness for all strong permitted lines except H beta. Spectral differences between samples divided by their relative X-ray brightness las measured by alpha(ox)) exceed those seen between complementary samples divided by luminosity or radio loudness. We propose that the Baldwin effect may be a secondary correlation to the primary relationship between alpha(ox) and emission line equivalent width. We conclude that either (1) W-lambda depends primarily on the shape of the ionizing continuum, as crudely characterized here by alpha(ox), or (2) both W-lambda and alpha(ox) are related to some third parameter characterizing the QSO physics. One such possibility is intrinsic warm absorption; a soft X-ray absorber situated between the broad and narrow line regions can successfully account for many of the properties observed. 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. EM pgreen@cfa.harvard.edu NR 48 TC 27 Z9 28 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP 170 EP 180 DI 10.1086/305537 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100016 ER PT J AU Kennicutt, RC Stetson, PB Saha, A Kelson, D Rawson, DM Sakai, S Madore, BF Mould, JR Freedman, WL Bresolin, F Ferrarese, L Ford, H Gibson, BK Graham, JA Han, MS Harding, P Hoessel, JG Huchra, JP Hughes, SMG Illingworth, GD Macri, LM Phelps, RL Silbermann, NA Turner, AM Wood, PR AF Kennicutt, RC Stetson, PB Saha, A Kelson, D Rawson, DM Sakai, S Madore, BF Mould, JR Freedman, WL Bresolin, F Ferrarese, L Ford, H Gibson, BK Graham, JA Han, MS Harding, P Hoessel, JG Huchra, JP Hughes, SMG Illingworth, GD Macri, LM Phelps, RL Silbermann, NA Turner, AM Wood, PR TI The Hubble Space Telescope key project on the extragalactic distance scale. XIII. The metallicity dependence of the Cepheid distance scale SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; distance scale; galaxies, distances and redshifts; galaxies, individual (M101, NGC 5457) ID PERIOD-LUMINOSITY RELATION; H-II REGIONS; ABSOLUTE PEAK BRIGHTNESS; BVRI CCD PHOTOMETRY; SPIRAL GALAXIES; PLANETARY-NEBULAE; OXYGEN ABUNDANCES; STANDARD CANDLES; DISCOVERY; VARIABLES AB Uncertainty in the metal-abundance dependence of the Cepheid variable period-luminosity (PL) relation remains one of the outstanding sources of systematic error in the extragalactic distance scale and in the Hubble constant. To test for such a metallicity dependence, we have used the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST) to observe Cepheids that span a range in oxygen abundance of 0.7 +/- 0.15 dex in two fields in the nearby spiral galaxy M101. A differential analysis of the PL relations in V and I in the two fields yields a marginally significant change in the inferred distance modulus on metal abundance, with delta(m-M)(o)/delta[CO/H] = -0.24 +/- 0.16 mag dex(-1). The trend is in the theoretically predicted sense that metal-rich Cepheids appear brighter and closer than metal-poor stars. External comparisons of Cepheid distances with those derived from three other distance indicators, in particular from the tip of the red giant branch method, further constrain the magnitude of any Z-dependence of the PL relation at V and I. The overall effects of any metallicity dependence on the distance scale derived with HST will be of the order of a few percent or less for most applications, though distances to individual galaxies at the extremes of the metal abundance range may be affected at the 10% level. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Inst Adv Studies, Weston, ACT 2611, Australia. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Royal Greenwich Observ, Cambridge CB3 0EZ, England. RP Kennicutt, RC (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 70 TC 234 Z9 234 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP 181 EP 194 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100017 ER PT J AU Fisher, D Fabricant, D Franx, M van Dokkum, P AF Fisher, D Fabricant, D Franx, M van Dokkum, P TI A spectroscopic survey of the galaxy cluster CL 1358+62 at z=0.328 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, individual (CL 1358 + 6245); galaxies, distances and redshifts; galaxies, evolution; galaxies, kinematics and dynamics; galaxies, structure ID DISTANT CLUSTERS; RICH CLUSTERS; COMA CLUSTER; EVOLUTION; SUBSTRUCTURE; POPULATIONS; PHOTOMETRY; MORPHOLOGY; 3C-295 AB We present a spectroscopic survey of the rich X-ray-selected galaxy cluster CL 1358+6245 at z = 0.328. When our 173 new multislit spectra of cluster galaxies are combined with data from the literature, we produce a catalog of 232 cluster members in a region 10' x 11' (3.5 Mpc x 3.8 Mpc) surrounding the brightest cluster galaxy. These data are used to study the structure and dynamics of the cluster and to examine the radial and velocity distributions as a function of spectral type. We classify the spectral types of the cluster members according to the strengths of the Balmer absorption lines (H delta, H gamma, and H beta) and the [O II] 3727 Angstrom emission line. We derive a mean redshift of z = 0.3283 +/- 0.0003 and a velocity dispersion of 1027(-45)(+51) km s(-1) for the 232 cluster members. However, the cluster velocity distribution is non-Gaussian, and we identify at least two subgroups with 10-20 members and dispersions of <400 km s(-1). The fraction of spectroscopically active galaxies (poststarburst and emission-line) in the core of the velocity distribution (within 0.6 sigma of the mean cluster velocity) is 16% +/- 4%, rising to 32% +/- 7% for galaxies in the tails of the velocity distribution (2.0 sigma from the mean cluster velocity). In total, the cluster is composed of 19% +/- 3% emission-line and 5% +/- 1% poststarburst galaxies. The velocity dispersion of the poststarburst galaxies is close to 2(1/2) times that of the absorption-line galaxies, consistent with free-fall accretion of the poststarburst galaxies. The changing mix of galaxy spectral types as a function of local galaxy density (or distance from the cluster center) in CL 1358+62 is similar to what is observed in nearby rich clusters. The percentage of emission-line galaxies increases steadily with radius from 9% +/- 3% within a radius of r(p) < 0.7 Mpc to 41% +/- 9% in our outermost radial bin at similar to 1.7 Mpc. The percentage of absorption-line galaxies falls from 84% +/- 9% to 59% +/- 11% over the same radial intervals. These results are consistent with the idea that the cluster grows through the accretion of late-type field galaxies, a fraction of which are transformed into poststarburst galaxies during the accretion event. Our high-S/N spectra of the "E + A" galaxies allow a detailed comparison with spectra of nearby merging and strongly interacting galaxy systems. We find that nearby mergers have stronger [O II] 3727 Angstrom emission ([O II] EW > 5 Angstrom) than that observed for our E + A galaxies. This implies either that the E + A galaxies in CL 1358 + 62 were not formed through major mergers, or that if they were formed via merging, their gas supply was quickly depleted, possibly by the intracluster medium. C1 Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg, Germany. EM fish@astro.rug.nl; dgf@spectra.harvard.edu; franx@astro.rug.nl; dokkum@astro.rug.nl NR 56 TC 101 Z9 102 U1 0 U2 0 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 1 PY 1998 VL 498 IS 1 BP 195 EP 212 DI 10.1086/305553 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100018 ER PT J AU Gammie, CF Popham, R AF Gammie, CF Popham, R TI Advection-dominated accretion flows in the Kerr metric. I. Basic equations SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; hydrodynamics; relativity ID BLACK-HOLES; DISKS; SHEAR AB We write and solve equations describing steady state, optically thin, advection-dominated accretion onto a Kerr black hole. The mean flow, described by the relativistic fluid equations, is axisymmetric and vertically averaged. The effect of turbulence in the flow is represented by a viscous shear stress. Our treatment differs in several important ways from earlier work: we use a causal prescription for the shear stress; we do not assume that the relativistic enthalpy is unity (this is important for rapidly rotating holes); and we use a relativistic equation of state. We present several representative solutions and use them to evaluate the importance of relativistic effects, to check our approximations, and to evaluate the robustness of the input physics. Detailed properties of the solutions are described in an accompanying paper. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Gammie, CF (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 40 TC 96 Z9 97 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP 313 EP 326 DI 10.1086/305521 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100031 ER PT J AU Soderblom, DR King, JR Siess, L Noll, KS Gilmore, DM Henry, TJ Nelan, E Burrows, CJ Brown, RA Perryman, MAC Benedict, GF McArthur, BJ Franz, OG Wasserman, LH Jones, BF Latham, DW Torres, G Stefanik, RP AF Soderblom, DR King, JR Siess, L Noll, KS Gilmore, DM Henry, TJ Nelan, E Burrows, CJ Brown, RA Perryman, MAC Benedict, GF McArthur, BJ Franz, OG Wasserman, LH Jones, BF Latham, DW Torres, G Stefanik, RP TI HD 98800: A unique stellar system of post-T Tauri stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, visual; circumstellar matter; stars, evolution; stars, individual(HD 98800); stars, pre-main-sequence ID SOLAR; HD-98800; ABUNDANCES; SEARCH AB HD 98800 is a system of four stars, and it has a large infrared excess that is thought to be due to a dust disk within the system. In this paper we present new astrometric observations made with Hipparcos, as well as photometry from Hubble Space Telescope WFPC2 images. Combining these observations and reanalyzing previous work allow us to estimate the age and masses of the stars in the system. Uncertainty in these ages and masses results from uncertainty in the temperatures of the stars and any reddening they may have. We find that HD 98800 is most probably about 10 Myr old, although it may be as young as 5 Myr or as old as 20 Myr. The stars in HD 98800 appear to have metallicities that are about solar. An age of 10 Myr means that HD 98800 is a member of the post-T Tauri class of objects, and we argue that the stars in HD 98800 can help us understand why post-T Tauris have been so elusive. HD 98800 may have formed in the Centaurus star-forming region, but it is extraordinary in being so young and yet so far from where it was born. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. European Space Agcy, Estec, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. Univ Texas, Mcdonald Observ, Austin, TX 78712 USA. Lowell Observ, Flagstaff, AZ 86001 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Soderblom, DR (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Noll, Keith/C-8447-2012 NR 39 TC 59 Z9 59 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP 385 EP 393 DI 10.1086/305542 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100038 ER PT J AU Uitenbroek, H AF Uitenbroek, H TI The effect of photospheric granulation on the determination of the lithium abundance in solar-type stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE convection; line, formation; radiative transfer; stars, abundances; stars, late-type; Sun, granulation ID MULTILEVEL RADIATIVE-TRANSFER; LAMBDA ITERATION METHOD; HELIOSEISMOLOGY LINES; CHROMOSPHERE; CONTINUUM AB I investigate non-local thermodynamic equilibrium (non-LTE) formation of the 670.6 nm Li I resonance doublet in the presence of convective surface inhomogeneities in solar-type stars. This doublet is widely used for lithium abundance determination in stars. It has been suggested that the presence of hot and cool elements in a stellar atmosphere due to convective heat transport might lead to an underestimate of lithium abundance by as much as a factor of 10 when the equivalent width of the doublet is analyzed in terms of a one-dimensional plane-parallel model atmosphere. To explore this possibility, I solved the two-dimensional non-LTE radiative transfer equations for a sufficiently large lithium model atom in a hydrodynamic simulation snapshot of the solar granulation. This was done for different values of the lithium abundance ranging from A(Li) = 0.0 to 3.3. In all cases the effects of the inhomogeneities in the atmosphere on lithium line strength are small, never amounting to more than 0.1 dex in the derived abundance. This occurs mainly for three reasons. First, because of the exponential decrease of density with height in the gravitationally stratified stellar atmosphere, radiation escapes mostly vertically with little horizontal exchange. Some lateral transfer does occur at the boundaries between hot and cold elements, but the effect of this exchange on the spatially averaged line strength cancels out. It leads to a smoothing over the surface rather than to a diminishing overall strength of the doublet. Second, the sharp drop in temperature over hot upwelling material, in contrast to the much shallower gradient over the dark intergranular lanes, causes the 670.6 nm doublet to be deeper and narrower in the former and broader in the latter. Consequently, the contrast of equivalent line width between profiles emerging over hot upflows and cold downflows is small. Finally, because of its small abundance the opacity scale in lithium ionizing continua is mostly set by H- bound-free processes. Optical depth unity at the photoionization edges, therefore, follows the contours of electron temperature, moderating contrast in the ionizing radiation field. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM HUitenbroek@cfa.harvard.edu NR 34 TC 35 Z9 35 U1 0 U2 0 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 1 PY 1998 VL 498 IS 1 BP 427 EP 440 DI 10.1086/305525 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100042 ER PT J AU Esser, R Edgar, RJ Brickhouse, NS AF Esser, R Edgar, RJ Brickhouse, NS TI High minor ion outflow speeds in the inner corona and observed ion charge states in interplanetary space SO ASTROPHYSICAL JOURNAL LA English DT Article DE interplanetary medium; Sun, corona; Sun, particle emission ID MAXWELLIAN ELECTRON-DISTRIBUTION; SOLAR-WIND; IRON IONIZATION; WHITE-LIGHT; TEMPERATURE; HOLE; ACCELERATION; EQUILIBRIUM; VELOCITY; ULYSSES AB Flow speeds recently derived from chromospheric/transition region and coronal observations indicate that the solar wind acceleration process takes place at heights in the solar atmosphere much lower than previously imagined. Doppler-dimming observations of the O VI gimel 1032 and gimel 1037 spectral lines show that this is not only true for the background electron-proton solar wind but also for minor ions. The limits that these observations place on the flow speed of the O+5 ions are at least a factor of 3-4 higher than the highest flow speeds expected from earlier minor ion studies. It is likely that other ions reach similar speeds in the inner corona. The interpretation of in situ charge state observations needs to be reexamined in light of these new velocity measurements. Large flow speeds imply that some species may not be dose to equilibrium in the inner corona at any distance. Given a large deviation from equilibrium, the use of charge state ratios to determine equilibrium temperatures may no longer be appropriate. Using the newest available atomic data together with the most recent observational constraints on electron temperatures, electron densities, and flow speeds, we find models with high minor ion outflow speeds of the order of the O+5 outflow speed (about 130-230 km s(-1) below 3 R-.) that are consistent with charge state observations. We then discuss how minor ion charge state observations can be used in future observational and theoretical studies to place limits on solar wind acceleration and heating mechanisms. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Esser, R (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Brickhouse, Nancy/0000-0002-8704-4473 NR 42 TC 37 Z9 37 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP 448 EP 457 DI 10.1086/305516 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM044 UT WOS:000073499100044 ER PT J AU Brandenburg, A Saar, SH Turpin, CR AF Brandenburg, A Saar, SH Turpin, CR TI Time evolution of the magnetic activity cycle period SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars, activity; stars, evolution; stars, late-type; stars, magnetic fields ID MAIN-SEQUENCE STARS; STELLAR ACTIVITY CYCLES; CHROMOSPHERIC VARIATIONS; EMISSION; ROTATION; DYNAMO; FIELD AB We propose a new interpretation of the relationships between the dynamo cycle period (P-cyc) as observed in Ca II H and K, the rotational period (P-rot), the activity level, and other stellar properties. Viewed within this framework, the data suggest that the dynamo alpha-parameter increases with magnetic field strength, contrary to the conventional idea of alpha-quenching. The data also suggest a possibly discontinuous dependence of the ratio of cycle to rotation frequency, omega(cyc)/Omega, as a function of Rossby number, Ro (or equivalently, activity or age). Stars evolve with omega(cyc)/Omega proportional to t(-0.35) (or RO-0.7), Until age t approximate to 2-3 Gyr (roughly at the Vaughan-Preston gap), where a sharp transition occurs, in which omega(cyc)/Omega increases by a factor of approximate to 6. Thereafter, evolution with omega(cyc)/Omega proportional to t(-0.35) continues. The age at which transition occurs may be mass dependent, with K stars making the transition first. C1 Univ Newcastle Upon Tyne, Dept Math, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Newcastle Upon Tyne, Dept Phys, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. RP Brandenburg, A (reprint author), Univ Newcastle Upon Tyne, Dept Math, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. RI Brandenburg, Axel/I-6668-2013 OI Brandenburg, Axel/0000-0002-7304-021X NR 36 TC 74 Z9 74 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP L51 EP L54 DI 10.1086/311297 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM045 UT WOS:000073499200012 ER PT J AU McCarthy, MC Travers, MJ Chen, W Gottlieb, CA Thaddeus, P AF McCarthy, MC Travers, MJ Chen, W Gottlieb, CA Thaddeus, P TI Laboratory detection of the carbon ring chain C9H2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, molecules; line, identification; molecular data; molecular processes; radio lines, ISM ID C6H AB The ring-chain C9H2 molecule, formed by substituting the carbon chain C6H for one of the hydrogen atoms of the carbene ring C3H2, one of the more abundant astronomical molecules, has been detected in the laboratory by Fourier transform microwave spectroscopy. Fifteen a-type rotational transitions between 6 and 14 GHz were measured to 2 kHz or better, and precise values were determined for the rotational and centrifugal distortion constants. With these, the entire radio spectrum can be calculated to better than 1 km s(-1) in equivalent radial velocity over the range of interest to radio astronomy. The strongest lines of C9H2 Like those of the smaller ring chain C7H2, were obtained with a diacetylene-neon discharge but were about 10 times weaker. Ab initio calculations have not been done for C9H2, and isomeric energies are not known, but by analogy with the shorter members of the sequence, the ring-chain carbene here is probably the most stable structure. Of the many possible isomers of C9H2, several may lie low enough in energy to be detectable in the laboratory and in space with present techniques. Ions and radicals with ring-chain structures are also excellent candidates for laboratory and astronomical detection. 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. NR 22 TC 14 Z9 14 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP L89 EP L92 DI 10.1086/311302 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM045 UT WOS:000073499200021 ER PT J AU Vikhlinin, A McNamara, BR Forman, W Jones, C Quintana, H Hornstrup, A AF Vikhlinin, A McNamara, BR Forman, W Jones, C Quintana, H Hornstrup, A TI Evolution of cluster X-ray luminosities and radii: Results from the 160 square degree rosat survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, general; surveys; X-rays, galaxies ID MEDIUM-SENSITIVITY SURVEY; GALAXIES; SAMPLE; EINSTEIN AB We searched for cluster X-ray luminosity and radius evolution using our sample of 203 galaxy clusters detected in the 160 deg(2) survey with the ROSAT PSPC (Vikhlinin et al.). With such a large area survey, it is possible, for the first time with ROSAT, to test the evolution of luminous clusters, L-X > 3 x 10(44) ergs s(-1) in the 0.5-2 keV band. We detect a factor of 3-4 deficit of such luminous clusters at z > 0.3 compared with the present. The evolution is much weaker or absent at modestly lower luminosities, (1-3) x 10(44) ergs s(-1). At still lower luminosities, we find no evolution from the analysis of the log N-log S relation. The results in the two upper L, bins are in agreement with the Einstein Extended Medium-Sensitivity Survey evolution result (Gioia et al.; Henry ct al.), which was obtained using a completely independent cluster sample. The low-L-X results are in agreement with other ROSAT surveys (e.g., Rosati et al.; Jones et al.). We also compare the distribution of core radii of nearby and distant (z > 0.4) luminous (with equivalent temperatures of 4-7 keV) clusters and detect no evolution. The ratio of average core radius for z similar to 0.5 and z < 0.1 clusters is 0.9 +/- 0.1, and the core radius distributions are remarkably similar. A decrease of cluster sizes incompatible with our data is predicted by self-similar evolution models for a high-Omega universe. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Space Res Inst, Moscow, Russia. Pontificia Univ Catolica Chile, Dept Astron & Astrophys, Santiago 22, Chile. Danish Space Res Inst, Copenhagen 2100 O, Denmark. RP Vikhlinin, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. OI Forman, William/0000-0002-9478-1682 NR 21 TC 68 Z9 68 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1998 VL 498 IS 1 BP L21 EP L25 DI 10.1086/311305 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM045 UT WOS:000073499200006 ER PT J AU Kalko, EKV Schnitzler, HU Kaipf, I Grinnell, AD AF Kalko, EKV Schnitzler, HU Kaipf, I Grinnell, AD TI Echolocation and foraging behavior of the lesser bulldog bat, Noctilio albiventris: preadaptations for piscivory? SO BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY LA English DT Article DE bats; echolocation; foraging; evolution; piscivory ID CF FM BAT; FISH-CATCHING BAT; PREY CAPTURE; FLIGHT PERFORMANCE; MYOTIS-DAUBENTONI; PIPISTRELLE BATS; WATER-SURFACE; SOUND PATTERN; LEPORINUS; CHIROPTERA AB We studied variability in foraging behavior of Noctilio albiventris (Chiroptera: Noctilionidae) in Costa Rica and Panama and related it to properties of its echolocation behavior. N. albiventris searches for prey in high (> 20 cm) or low (< 20 cm) search flight, mostly over water. It captures insects in mid-air (aerial captures) and from the water surface (pointed dip). We once observed an individual dragging its feet through the water (directed random rake). In search flight, N. albiventris emits groups of echolocation signals (duration 10-11 ms) containing mixed signals with constant-frequency (CF) and frequency-modulated (FM) components, or pure CF signals. Sometimes, mostly over land, it produces long FM signals (duration 15-21 ms). When N. albiventris approaches prey in a pointed dip or in aerial captures, pulse duration and pulse interval are reduced, the CF component is eliminated, and a terminal phase with short FM signals (duration 2 ms) at high repetition rates (150-170 Hz) is emitted. Except for the last pulses in the terminal phase N. albiventris avoids overlap between emitted signals and echoes returning from prey. During rakes, echolocation behavior is similar to that in high search flight. We compare N. albiventris with its larger congener, N. leporinus, and discuss behavioral and morphological specializations that can be interpreted as preadaptations favoring the evolution of piscivory as seen in N. leporinus. Prominent among these specializations are the CF components of the echolocation signals which allow detection and evaluation of fluttering prey amidst clutter-echoes, high variability in foraging strategy and the associated echolocation behavior, as well as morphological specializations such as enlarged feet for capturing prey from the water surface. C1 Univ Tubingen, D-72076 Tubingen, Germany. Smithsonian Trop Res Inst, Balboa, Panama. Natl Museum Nat Hist, MRC 108, Washington, DC 20560 USA. Univ Calif Los Angeles, Sch Med, Dept Physiol, Los Angeles, CA 90024 USA. Univ Calif Los Angeles, Sch Med, Ahmanson Lab Neurobiol, Los Angeles, CA 90024 USA. RP Kalko, EKV (reprint author), Univ Tubingen, Morgenstelle 28, D-72076 Tubingen, Germany. EM Elizabeth.Kalko@uni-tuebingen.de NR 67 TC 48 Z9 51 U1 0 U2 21 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0340-5443 EI 1432-0762 J9 BEHAV ECOL SOCIOBIOL JI Behav. Ecol. Sociobiol. PD MAY PY 1998 VL 42 IS 5 BP 305 EP 319 DI 10.1007/s002650050443 PG 15 WC Behavioral Sciences; Ecology; Zoology SC Behavioral Sciences; Environmental Sciences & Ecology; Zoology GA ZP983 UT WOS:000073809000002 ER PT J AU Ochoa-Acuna, H Francis, JM Boness, DJ AF Ochoa-Acuna, H Francis, JM Boness, DJ TI Interannual variation in birth mass and postnatal growth rate of Juan Fernandez fur seals SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID DIFFERENTIAL MATERNAL INVESTMENT; SOUTHERN ELEPHANT SEALS; HALICHOERUS-GRYPUS; ARCTOCEPHALUS-GALAPAGOENSIS; PARENTAL INVESTMENT; GREY SEAL; PUPS AB The objectives of this study were to establish body mass at birth, postnatal growth rate, and the factors that influence these parameters for the Juan Fernandez fur seal, Arctocephalus philippii. Females of this species have an unusual attendance pattern in which foraging trips and shore visits last, on average, 12.3 and 5.3 days, respectively. Pup mass was obtained from cohorts born during the reproductive seasons in 1988 through 1992. Birth masses of male and female pups were significantly different, averaging 6.1 and 5.5 kg, respectively (F = 13.2, P < 0.0003, n = 238). Birth masses also differed among cohorts, being lowest in 1992 and highest in 1990. During the first 2 months of life, male and female pups grew at the same rate (79 +/- 61.5 g.day(-1) (mean +/- SD); F-[1] = 0.03, P = 0.8562). Interannual differences in growth rate during the first month were significant (F-[4] = 8.14, P < 0.0001), as was the interaction between month and year effects (F-[2] = 6.81, P = 0.0012). Growth rates for the 1990 cohort were lower than those in all other years except 1992. Birth masses and postnatal growth rates of Juan Fernandez fur seal pups are comparable to those of other otariid species. C1 Univ Florida, Dept Zool, Gainesville, FL 32611 USA. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Ochoa-Acuna, H (reprint author), Univ Florida, Dept Zool, POB 118525, Gainesville, FL 32611 USA. NR 40 TC 12 Z9 12 U1 0 U2 4 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD MAY PY 1998 VL 76 IS 5 BP 978 EP 983 DI 10.1139/cjz-76-5-978 PG 6 WC Zoology SC Zoology GA 127GU UT WOS:000076343200025 ER PT J AU West, SA Compton, SG Vincent, SL Herre, EA Cook, JM AF West, SA Compton, SG Vincent, SL Herre, EA Cook, JM TI Virginity in haplodiploid populations: a comparison of estimation methods SO ECOLOGICAL ENTOMOLOGY LA English DT Article DE fig wasps; parasitoid; sex ratio; sperm-depletion; virginity; wing dimorphism ID CONSTRAINED SEX ALLOCATION; FIG WASPS; HYMENOPTERA; RATIOS AB 1. The presence of ovipositing virgin females, who are able to produce only male offspring, may have several important consequences for the evolution of reproductive strategies. 2. The prevalence of virginity for five fig wasp species was estimated using three different methods: (1) the proportion of females developing in fruit that contained no conspecific males; (2) dissection of females caught on sticky traps; and (3) dissection of females that had emerged from their galled flowers into the fruit cavity. 3. The estimates obtained by method 1 (females developing in single sex broods) were lower than those obtained by the other methods. 4. Across species, the estimates obtained by method 1 (females developing in single sex broods) were significantly correlated with those obtained by method 2 (sticky trap caught females). 5. Mating with sperm-depleted males is unlikely to occur in these species. C1 Univ Edinburgh, Inst Cell Anim & Populat Biol, Edinburgh EH9 3JT, Midlothian, Scotland. Imperial Coll Sci Technol & Med, Dept Biol, London, England. Univ Leeds, Dept Biol, Leeds LS2 9JT, W Yorkshire, England. Smithsonian Trop Res Inst, Balboa, Panama. RP West, SA (reprint author), Univ Edinburgh, Inst Cell Anim & Populat Biol, Kings Bldg,W Mains Rd, Edinburgh EH9 3JT, Midlothian, Scotland. RI Cook, James/D-6423-2011; West, Stuart/M-3608-2014 OI Cook, James/0000-0001-8447-6126; West, Stuart/0000-0003-2152-3153 NR 24 TC 13 Z9 14 U1 0 U2 5 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 MAY PY 1998 VL 23 IS 2 BP 207 EP 210 PG 4 WC Entomology SC Entomology GA ZT348 UT WOS:000074076200013 ER PT J AU Benninger, LK Suayah, IB Stanley, DJ AF Benninger, LK Suayah, IB Stanley, DJ TI Manzala lagoon, Nile delta, Egypt: modern sediment accumulation based on radioactive tracers SO ENVIRONMENTAL GEOLOGY LA English DT Article DE Manzala lagoon; Nile delta; Chernobyl; radionuclides ID CHERNOBYL SOURCE TERM; PLUTONIUM; GEOCHEMISTRY; SUBSIDENCE; PB-210 AB This study was undertaken to determine whether recent anthropogenic changes in the Nile basin have affected the modern rate of sediment accumulation in the Nile delta. Excess (210)pb, Cs-137, and Pu-239,Pu-240 were used to develop a sediment chronology for a core from central Manzala lagoon, the delta sector which has had the highest average rate of sediment accumulation during the Holocene (to about 0.7 cm year(-1)). Excess Pb-210 was detected in the top 32 cm of the core, yielding an accumulation rate of 1.2 cm year(-1), higher than the mean rate for the Holocene. A high Cs-137/Pu-239,Pu-240 ratio requires a reactor source (possibly Chernobyl) for these nuclides. Low concentrations of excess (210)pb and weapons-fallout nuclides precluded recognition of changes in sediment accumulation rate in Manzala lagoon during this century and may limit the use of tracer radionuclides for modern sediment chronology in the Nile delta. C1 Univ N Carolina, Dept Geol, Chapel Hill, NC 27599 USA. Smithsonian Inst, Natl Museum Nat Hist, Deltas Global Change Program, Washington, DC 20560 USA. RP Benninger, LK (reprint author), Univ N Carolina, Dept Geol, CB 3315,Mitchell Hall, Chapel Hill, NC 27599 USA. NR 37 TC 16 Z9 17 U1 1 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0943-0105 J9 ENVIRON GEOL JI Environ. Geol. PD MAY PY 1998 VL 34 IS 2-3 BP 183 EP 193 PG 11 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA ZQ055 UT WOS:000073816900014 ER PT J AU Reeder, AL Foley, GL Nichols, DK Hansen, LG Wikoff, B Faeh, S Eisold, J Wheeler, MB Warner, R Murphy, JE Beasley, VR AF Reeder, AL Foley, GL Nichols, DK Hansen, LG Wikoff, B Faeh, S Eisold, J Wheeler, MB Warner, R Murphy, JE Beasley, VR TI Forms and prevalence of intersexuality and effects of environmental contaminants on sexuality in cricket frogs (Acris crepitans) SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article DE Acris crepitans; amphibian; contaminants; endocrine disruptors; intersexuality; polychlorinated biphenyls; polychlorinated dibenzofurans ID PREPUBERTAL FEMALE RATS; SEX DETERMINATION; RECEPTOR; PCBS AB Cricket frog (Arris crepitans) from several different sites in Illinois were collected to assess the effects of environmental contamination on the prevalence of intersex gonads. Of 341 frogs collected in 1993, 1994, and 1995, 2.7% were intersex individuals. There was no statistically significant relationship between the chemical compounds detected and cricket frog intersexuality. However, there was an association approaching significance (p = 0.07) between the detection of atrazine and intersex individuals. A comparison of reference sites with sites thar had point polychlorinated biphenyl (PCB) and polychlorinated dibenzofuran (PCDF) contamination revealed a significant relationship between sex-ratio reversal and contamination with PCBs and PCDFs. The sex ratio of juvenile frogs studied from three sites with PCB and PCDF point contamination favored males over females, which was the opposite of the sex ratio in control ponds (p = 0.0007). The statistically significant correlation between organochlorine contamination and sex-ratio reversal suggests PCBs and PCDFs can influence cricket frog sexual differentiation. The current study suggests that in cricket frogs, sex ratios and the prevalence of intersex gonads are altered by environmental contamination. C1 Univ Illinois, Coll Vet Med, Dept Vet Biosci, Urbana, IL 61801 USA. Univ Illinois, Coll Agr Consumer & Environm Sci, Dept Anim Sci, Urbana, IL 61801 USA. Univ Illinois, Coll Agr Consumer & Environm Sci, Dept Nat Resources & Environm Sci, Urbana, IL 61801 USA. Univ Illinois, Coll Vet Med, Dept Vet Pathobiol, Urbana, IL 61801 USA. Smithsonian Inst, Natl Zool Pk, Dept Pathol, Washington, DC 20008 USA. RP Beasley, VR (reprint author), Univ Illinois, Coll Vet Med, Dept Vet Biosci, 2001 S Lincoln Ave, Urbana, IL 61801 USA. OI Wheeler, Matthew/0000-0001-5589-357X NR 41 TC 97 Z9 102 U1 2 U2 18 PU US DEPT HEALTH HUMAN SERVICES PUBLIC HEALTH SERVICE PI RES TRIANGLE PK PA NATL INST HEALTH, NATL INST ENVIRONMENTAL HEALTH SERVICES, PO BOX 12233, RES TRIANGLE PK, NC 27709-2233 USA SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD MAY PY 1998 VL 106 IS 5 BP 261 EP 266 PG 6 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 111UX UT WOS:000075457600019 PM 9647894 ER PT J AU Giaramita, M MacPherson, GJ Phipps, SP AF Giaramita, M MacPherson, GJ Phipps, SP TI Petrologically diverse basalts from a fossil oceanic forearc in California: The Llanada and Black Mountain remnants of the coast range ophiolite SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article ID NORTHERN-CALIFORNIA; TECTONIC IMPLICATIONS; GEOCHEMICAL EVIDENCE; WESTERN CALIFORNIA; TROODOS OPHIOLITE; MARIANA TROUGH; VOLCANIC-ROCKS; CRUST TERRANE; ARC; LAVAS AB Basalts from two geographically separated fragments of the California Coast Range ophiolite are very different petrographically, mineralogically, and geochemically, Pillow lavas from the Llanada Coast Range ophiolite remnant are mostly Cr-rich and TiO2-poor basalts in which Ti does not increase with increasing Fe/(Fe + Mg); some Cr-poor siliceous rocks are also present. Most Llanada rocks are depleted in Light rare earth elements (REE), although a few show slight light REE enrichment, Ti/V ratios are are-like. The Llanada basalts appear to be island-are tholeiites that have limited boninitic affinities-i.e., products of suprasubduction zone magmatism, Basalts from the Black Mountain Coast Range ophiolite remnant near St. Helena are TiO2-rich relative to those from most other Coast Range ophiolite fragments, and TiO2 increases with increasing Fe/(Fe + Mg). Black Mountain basalts are light REE depleted, REE enriched overall relative to Llanada lavas, and have mid-oceanic-ridge basalt (MORB)-like Ti/V ratios. These characteristics are similar to those of MORE, but elevated Th/Ta ratios suggest a suprasubduction-zone origin for the Black Mountain lavas. These results show that the Coast Range ophiolite is highly diverse, containing island-arc tholeiites and possibly suprasubduction zone-related MORB-like components. In the Coast Range ophiolite as a whole, the apparent preponderance of island-are tholeiite lavas such as those at Llanada over MORB-like lavas such as those at Black Mountain favors a forearc over a backarc setting for the origin of the ophiolite, Other data suggest that the Coast Range ophiolite locally contains ocean-island basalts (OIBs), Moreover, serpentinite-rich ophiolitic detritus overlying Coast Range ophiolite sergentinite suggests that, in some areas, the basaltic section of the oceanic crust was missing completely, and serpentinized harzburgite was exposed at the sea floor. These relationships are similar to those in the modern Mariana forearc, which exposes a complex amalgam of boninitic and arc-tholeiitic suprasubduction zone-related crust, MORB and OIB crust, and serpentinized harzburgite. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. Univ Penn, Dept Geol, Philadelphia, PA 19104 USA. RP Giaramita, M (reprint author), Calif State Univ Stanislaus, Dept Phys & Geol, 801 W Monte Vista Ave, Turlock, CA 95380 USA. EM mariog@toro.csustan.edu NR 87 TC 34 Z9 34 U1 0 U2 1 PU ASSOC ENGINEERING GEOLOGISTS GEOLOGICAL SOCIETY AMER PI COLLEGE STN PA TEXAS A & M UNIV, DEPT GEOLOGY & GEOPHYSICS, COLLEGE STN, TX 77843-3115 USA SN 0016-7606 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD MAY PY 1998 VL 110 IS 5 BP 553 EP 571 DI 10.1130/0016-7606(1998)110<0553:PDBFAF>2.3.CO;2 PG 19 WC Geosciences, Multidisciplinary SC Geology GA ZM146 UT WOS:000073509300002 ER PT J AU Thomas, W Hegels, E Slijkhuis, S Spurr, R Chance, KI AF Thomas, W Hegels, E Slijkhuis, S Spurr, R Chance, KI TI Detection of biomass burning combustion products in Southeast Asia from backscatter data taken by the GOME spectrometer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ABSORPTION AB We show that atmospheric UV/visible backscatter spectra obtained by the Global Ozone Monitoring Experiment (GOME) spectrometer on board the ESA ERS-2 satellite may be used to retrieve column amounts of key trace species associated with smoke cloud combustion from biomass burning events. This paper focuses on the recent rain forest burning in SE Asia (August-October 1997). For ground scenes with low cloudiness, differential absorption fitting applied to backscatter spectra yields column distributions of NO2 and H2CO in and around smoke-polluted regions. A two-fold increase in the vertical NO2 content is apparent over large parts of the smoke cloud; this clearly indicates the ability of GOME to measure tropospheric NO2 content. H2CO is detected only in areas closest to combustion sources. Slant column amounts in the range 2.5 - 4 x 10(16) mol cm(-2) have been determined; these correspond with previous estimations of vertical columns of H2CO for biomass Savannah burning. C1 DLR, DFD, Deutsch Fernerkundungsdatenzentrum, Oberpfaffenhofen, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Thomas, W (reprint author), DLR, DFD, Deutsch Fernerkundungsdatenzentrum, Oberpfaffenhofen, Germany. OI Chance, Kelly/0000-0002-7339-7577 NR 9 TC 55 Z9 56 U1 3 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1317 EP 1320 DI 10.1029/98GL01087 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900008 ER PT J AU Bockelee-Morvan, D Gautier, D Lis, DC Young, K Keene, J Phillips, T Owen, T Crovisier, J Goldsmith, PF Bergin, EA Despois, D Wootten, A AF Bockelee-Morvan, D Gautier, D Lis, DC Young, K Keene, J Phillips, T Owen, T Crovisier, J Goldsmith, PF Bergin, EA Despois, D Wootten, A TI Deuterated water in comet C 1996 B2 (Hyakutake) and its implications for the origin of comets SO ICARUS LA English DT Article DE comets; deuterium; Solar Nebula; submillimeter spectroscopy ID OUTER SOLAR-SYSTEM; HYDROGEN-ISOTOPE-EXCHANGE; DENSE INTERSTELLAR CLOUDS; MONODEUTERATED METHANE; ROTATIONAL LINES; PARENT MOLECULES; D/H RATIO; HOT CORES; DEUTERIUM; P/HALLEY AB The close approach to the Earth of Comet C/1996 B2 (Hyakutake) in March 1996 allowed searches for minor volatile species outgassed from the nucleus. We report the detection of deuterated water (HDO) through its 1(01)-0(00) rotational transition at 464.925 GHz using the Caltech Submillimeter Observatory. We also present negative results of a sensitive search for the J(5-4) line of deuterated hydrogen cyanide (DCN) at 362.046 GHz. Simultaneous observations of two rotational lines of methanol together with HDO in the same spectrum allow us to determine the average gas temperature within the telescope beam to be 69 +/- 10 K. We are thus able to constrain the excitation conditions in the inner coma and determine reliably the HDO production rate as (1.20 +/- 0.28) x 10(26) s(-1) on March 23-24, 1996. Available IR, UV, and radio measurements led to a water production rate of (2.1 +/- 0.5) x 10(29) s(-1) at the time of our HDO observations. The resulting D/H ratio in cometary water is thus (29 +/- 10) x 10(-5), in good agreement with the values of(30.8-(+3.8)(5.3)) x 10(-5) (H. Balsiger et al., 1995, J, Geophys. Res. 100, 5827-5834). and (31.6 +/- 3.4) x 10(-5) (P. Eberhard et al., 1995, Astron. Astrophys. 302, 301-316) determined in Comet P/Halley from in situ ion mass spectra, The inferred 3 sigma upper limit for the D/H ratio in HCN is 1%. Deuterium abundance is a key parameter for studying the origin and the early evolution of the Solar System and of its individual bodies. Our HDO measurement confirms that, in cometary water, deuterium is enriched by a factor of at least 10 relative to the protosolar ratio, namely the D/H ratio in H(2) in the primitive Solar Nebula which formed from the collapse of the protosolar cloud. This indicates that cometary water has preserved a major part of the high D/H ratio acquired in this protosolar cloud through ion-molecule isotopic exchanges or grain-surface reactions and was not re-equilibrated with Hz in the Solar Nebula. However, there are strong presumptions that interstellar grains were partly mixed in the early nebula prior to cometary formation with water reprocessed in the warm inner part of the nebula and transported by turbulent diffusion. Scenarios of formation of comets consistent with these results are discussed. (C) 1998 Academic Press. C1 Observ Paris, F-92195 Meudon, France. CALTECH, Pasadena, CA 91125 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Cornell Univ, NAIC, Ithaca, NY 14853 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Observ Bordeaux, F-33270 Floirac, France. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. RP Bockelee-Morvan, D (reprint author), Observ Paris, F-92195 Meudon, France. EM domi@obspm.fr RI Goldsmith, Paul/H-3159-2016 NR 95 TC 181 Z9 182 U1 4 U2 12 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 1998 VL 133 IS 1 BP 147 EP 162 DI 10.1006/icar.1998.5916 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU381 UT WOS:000074191400010 ER PT J AU Ferrari, FD Dahms, HU AF Ferrari, FD Dahms, HU TI Segmental homologies of the maxilliped of some copepods as inferred by comparing setal numbers during copepodid development SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Article ID CLAUSIDIIDAE AB Segmental homologies of the maxillipeds of Longipedia americana, Coullana canadensis, Macrosetella gracilis, Hemicyclops adherens, and Troglocyclops janstocki are inferred by comparing segmental and setal numbers at CI, and changes in setal numbers during the copepodid phase of development, with published accounts of the calanoids Ridgewayia klausruetzleri and Pleuromamma xiphias. The unsegmented endopod of L. americana is a complex of 4 presumptive segments and the unsegmented endopod of C. canadensis is a complex of 3 presumptive segments. The endopod of T. janstocki appears to be 3-segmented, but the middle segment is a complex of 3 presumptive segments. Macrosetella gracilis has an unsegmented endopod of 2 presumptive segments; the distal segment is attenuate, forming a clawlike structure. Hemicyclops adherens has a 2-segmented endopod; the prominent, clawlike terminal structure on the maxilliped of the adult male is an attenuation of the distal endopodal segment. A homologous but more complex attenuation of that segment is present on the maxilliped of all of its copepodid stages including the adult female. C1 Natl Museum Nat Hist, Smithsonian Inst, Washington, DC 20560 USA. Univ Oldenburg, Arbeitsgrp Zoomorphol, Fachbereich 7, D-26111 Oldenburg, Germany. RP Ferrari, FD (reprint author), Natl Museum Nat Hist, Smithsonian Inst, MRC 534, Washington, DC 20560 USA. NR 12 TC 14 Z9 16 U1 0 U2 0 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD MAY PY 1998 VL 18 IS 2 BP 298 EP 307 DI 10.2307/1549323 PG 10 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA ZN085 UT WOS:000073607900009 ER PT J AU Reid, JW Spooner, JD AF Reid, JW Spooner, JD TI Stolonicyclops heggiensis, new genus, new species, from Georgia, U.S.A. (Copepoda : Cyclopoida : Cyclopidae) SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Article AB A previously unknown genus and species of cyclopoid copepod, Stolonicyclops heggiensis, was discovered in seepage areas on Heggie's Rock, a granite monadnock in Georgia, U.S.A. The genus is characterized by leg 5 fused to the somite, with 1 dorsal sera and 2 ventral setae on a small knob; the antennule of 11 segments in the female; the swimming legs with 2-segmented rami, except leg 4 endopodite segments partly fused in the female; the spine and sera formulae of swimming legs 2,3,3,3 and 5,4,4,4, respectively; the lack of a sera on the medial (inner) corner of the coxopodite of legs 2-4; leg 4 endopodite segment 2 with 5 appendages; and the lack of sexual dimorphism in the swimming legs, except for the difference in leg 4 endopodite fusion. In several respects, S. heggiensis resembles Bryocyclops (Palaeocyclops) jankowskajae Monchenko from Kazakhstan and Uzbekistan. However, the lack of modified appendages of leg 3 in the male of S. heggiensis precludes assigning it to the genus Bryocyclops. The nature of leg 3 of the male and other plesiomorphic characters of S. heggiensis may indicate that its ancestor diverged earlier than Palaeocyclops from the Bryocyclops ancestral line. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool MRC163, Washington, DC 20560 USA. Univ S Carolina, Dept Biol & Geol, Aiken, SC 29801 USA. RP Reid, JW (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool MRC163, Washington, DC 20560 USA. NR 25 TC 11 Z9 11 U1 0 U2 1 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD MAY PY 1998 VL 18 IS 2 BP 405 EP 411 DI 10.2307/1549333 PG 7 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA ZN085 UT WOS:000073607900019 ER PT J AU Bunch, TD Vorontsov, NN Lyapunova, EA Hoffmann, RS AF Bunch, TD Vorontsov, NN Lyapunova, EA Hoffmann, RS TI Chromosome number of Severtzov's sheep (Ovis ammon severtzovi): G-banded karyotype comparisons within Ovis SO JOURNAL OF HEREDITY LA English DT Article ID EVOLUTION; PATTERNS AB Severtzov's sheep (Ovis ammon severtzovi; Nasonov 1914) has a 2n = 56 diploid chromosome number and a karyotype consisting of two pairs of biarmed and 25 pairs of acrocentric autosomes, a large acrocentric X, and a minute biarmed Y. The G-banding patterns of the largest pair of biarmed chromosomes were identical to those of the largest biarmed chromosomes in all wild and domestic sheep of the genus Ovis. The banding patterns of the second pair of biarmed chromosomes were identical to the third pair of biarmed chromosomes in all sheep of the genus Ovis with 2n = 54 and to the third largest pair of chromosomes in the 2n = 52 karyotype of the Siberian snow sheep (O. nivicola). The G-banded karyotype of Severtzov's sheep is consistent with all subspecies of argali (O. ammon spp.) that have been karyotyped. Numerical ascription of acrocentric chromosome equivalents based upon the fundamental karyotype of Ovis that gave rise to the biarmed chromosomes of severtzovi are 1 and 3, and 5 and 11 for the largest and second largest biarmed chromosomes, respectively. Based upon diploid chromosome number and G bands, Severtzov's sheep should be considered a subspecies of argali and not a urial. C1 Utah State Univ, Dept Anim Dairy & Vet Sci, Logan, UT 84322 USA. Russian Acad Sci, Inst Dev Biol, Moscow, Russia. Natl Museum Nat Hist, Smithsonian Inst, Washington, DC 20560 USA. RP Bunch, TD (reprint author), Utah State Univ, Dept Anim Dairy & Vet Sci, Logan, UT 84322 USA. RI Lyapunova, Elena/A-4696-2016 NR 29 TC 4 Z9 9 U1 0 U2 0 PU OXFORD UNIV PRESS INC PI CARY PA JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA SN 0022-1503 J9 J HERED JI J. Hered. PD MAY-JUN PY 1998 VL 89 IS 3 BP 266 EP 269 DI 10.1093/jhered/89.3.266 PG 4 WC Evolutionary Biology; Genetics & Heredity SC Evolutionary Biology; Genetics & Heredity GA ZU606 UT WOS:000074214900014 PM 9656470 ER PT J AU Steppan, SJ AF Steppan, SJ TI Phylogenetic relationships and species limits within Phyllotis (Rodentia : Sigmodontinae): Concordance between MTDNA sequence and morphology SO JOURNAL OF MAMMALOGY LA English DT Article DE Phyllotis; phylogeny; cytochrome b; speciation; species limits; biogeography; Andes ID MITOCHONDRIAL-DNA; GENE TREES; CRICETIDAE; EVOLUTION AB Phylogenetic relationships and species limits within the South American rodent genus Phyllotis were estimated using nucleotide sequence data from a 973 base-pair region of the mitochondrial gene, cytochrome b. Geographic variation and species limits were assessed by sequencing individuals from multiple populations and morphometric analyses of skulls and skins. Results supported the following clades: Phyllotis plus Auliscomys exclusive of Graomys, the darwini species group, and a northerly distributed species-pair of P. amicus and P. andium. The phylogeny, genetic divergence estimates, and morphology indicated that P. xanthopygus rupestris is polyphyletic and populations from the Pacific slope of the Andes currently assigned to that taxon are specifically distinct, These populations are placed in the newly elevated P. limatus and an emended diagnosis is provided. Biogeographic and phylogenetic patterns are most consistent with successive colonization of the Pacific slopes by P. xanthopygus, possibly through range expansion and contraction, over a short period of time relative to the age of the clade. C1 Field Museum Nat Hist, Div Mammals, Chicago, IL 60605 USA. Univ Chicago, Comm Evolutionary Biol, Chicago, IL 60637 USA. RP Steppan, SJ (reprint author), Smithsonian Museum Support Ctr, Lab Mol Systemat, 4210 Silver Hill Rd, Suitland, MD 20746 USA. NR 41 TC 47 Z9 52 U1 0 U2 12 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 MAY PY 1998 VL 79 IS 2 BP 573 EP 593 DI 10.2307/1382988 PG 21 WC Zoology SC Zoology GA ZP664 UT WOS:000073776100020 ER PT J AU Zotz, G Andrade, JL AF Zotz, G Andrade, JL TI Water relations of two co-occurring epiphytic bromeliads SO JOURNAL OF PLANT PHYSIOLOGY LA English DT Article DE Tillandsia; Guzmania; bromeliads; epiphytes; water relations; crassulacean acid metabolism; Barro Colorado Island ID GUZMANIA-MONOSTACHIA; COMPARATIVE ECOPHYSIOLOGY; PHYSIOLOGICAL ECOLOGY; HABITAT PREFERENCE; TROPICAL EPIPHYTES; C-3 BROMELIADS; CAM; TRINIDAD; BALANCE; STRESS AB The water relations of the co-occurring epiphytic bromeliads, Guzmania monostachya and Tillandsia fasciculata, were studied in situ in the lowland tropical forest of Barro Colorado Island, Panama. Particular attention was paid to differences in the water relations of smaller and larger plants. Both species showed moderate, but significant seasonal changes in leaf water status and CAM-activity, measured as nocturnal acidification. When water was withheld from plants, 24-h whole plant water loss decreased to a minimum after 4-5 days. There were no significant interspecific or size-related differences in area-based transpiration rates. Due to a lower ratio of plant leaf area to plant water content (LA/PWC), similar area-based transpiration rates resulted in lower relative water losses in T. fasciculata. Smaller plants suffered significantly higher relative water losses in G. monostachya, but not in T. fasciculata. The observed differences in the water relations of smaller individuals may be responsible for the differences in the spatial distribution in host trees. C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Wurzburg, Lehrstuhl Bot 2, D-97082 Wurzburg, Germany. RP Zotz, G (reprint author), Smithsonian Trop Res Inst, Apdo 2072, Balboa, Panama. NR 45 TC 38 Z9 45 U1 2 U2 23 PU GUSTAV FISCHER VERLAG PI JENA PA VILLENGANG 2, D-07745 JENA, GERMANY SN 0176-1617 J9 J PLANT PHYSIOL JI J. Plant Physiol. PD MAY PY 1998 VL 152 IS 4-5 BP 545 EP 554 PG 10 WC Plant Sciences SC Plant Sciences GA ZQ967 UT WOS:000073921400031 ER PT J AU Barone, JA AF Barone, JA TI Effects of light availability and rainfall on leaf production in a moist tropical forest in central Panama SO JOURNAL OF TROPICAL ECOLOGY LA English DT Article DE Barro Colorado Island; leaf phenology; light availability; Panama; PAR; rainfall; tropical forests ID COSTA-RICA; UNDERSTORY COMMUNITY; DECIDUOUS FOREST; PHENOLOGY; ABUNDANCE; HERBIVORY; TREES; CONSEQUENCES; PATTERNS; LOWLANDS AB New leaf production in seasonal tropical forests may result from changes in water or light availability. In this study, the relationship between leaf flushing, photosynthetically active radiation (PAR) and rainfall was examined for understorey saplings in a moist tropical forest over one year. During the wet season, weeks with greater PAR were correlated with a greater proportion of saplings flushing new leaves during subsequent weeks in nine out of ten species. Rainfall was negatively correlated with subsequent leafing during the wet season for six of ten species. However, during the dry season, rainfall was positively correlated with leafing during the following weeks for six species, but the relationship was much weaker. PAR in the dry season was negatively correlated with flushing in eight species. These results support the hypothesis that under well-watered conditions, light limits leaf production, and peaks in insolation result in greater leaf production. C1 Univ Utah, Dept Biol, Salt Lake City, UT 84112 USA. RP Barone, JA (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 37 TC 18 Z9 19 U1 0 U2 5 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0266-4674 J9 J TROP ECOL JI J. Trop. Ecol. PD MAY PY 1998 VL 14 BP 309 EP 321 DI 10.1017/S0266467498000248 PN 3 PG 13 WC Ecology SC Environmental Sciences & Ecology GA 102FH UT WOS:000074913400004 ER PT J AU Neale, PJ Cullen, JJ Davis, RF AF Neale, PJ Cullen, JJ Davis, RF TI Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID BIOLOGICAL WEIGHTING FUNCTION; SHORT-TERM VARIATIONS; ANTARCTIC OZONE HOLE; SOUTHERN-OCEAN; BRANSFIELD STRAIT; ACTION SPECTRA; UV-RADIATION; B RADIATION; DEPLETION; ICE AB To assess the potential impacts of ozone depletion on photosynthesis in the Southern Ocean, we need to know more about effects of ultraviolet radiation (UV) on phytoplankton in Antarctic waters, where, in addition to variable stratospheric ozone, temporal and regional differences in vertical mixing might influence photosynthesis and photoacclimation of phytoplankton assemblages. Toward this end, we quantified the responses to UV of Antarctic phytoplankton in the Weddell-Scotia Confluence during the austral spring of 1993. Experimental results on spectral sensitivity of photosynthesis were fit statistically to a model-that incorporated uninhibited photosynthesis as a function of photosynthetically available radiation (PAR), wavelength-dependence of inhibition, and the kinetics of photosynthesis during exposure to UV. In contrast to previous results on UV-induced photoinhibition in a diatom culture at 20 degrees C, natural phytoplankton from open waters of the Antarctic showed no ability to counter UV-induced inhibition of photosynthesis during exposures of 0.5-4 h: the rate of photosynthesis declined exponentially as a function of cumulative exposure, and inhibition was not reversed during incubations for up to 3.5 h under benign conditions. The results suggest that nonlinear exposure-response relationships are necessary for modeling UV-dependent photosynthesis in the surface mixed layer of the springtime Weddell-Scotia Confluence. Consequently, we modified our laboratory-based model of photosynthesis and photoinhibition to describe photoinhibition as a nonlinear function of biologically weighted cumulative exposure to damaging irradiance. The model described similar to 90% of the spectrally dependent experimental variation in photosynthetic rate, and yielded six biological weighting functions (BWFs) for phytoplankton in the Weddell-Scotia Confluence. Assemblages from different stations showed substantial variability in sensitivity to UV. Tolerance of UV was generally highest in assemblages from shallower mixed layers, which presumably had experienced higher irradiance, including W, prior to sampling. The BWFs of assemblages that seemed acclimated to low irradiance showed the highest sensitivity to UV yet seen for Southern Ocean phytoplankton. The pattern of UV sensitivity was consistent with acclimation, but also with selection against less tolerant species. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. Dalhousie Univ, Dept Oceanog, Halifax, NS B3H 4J1, Canada. Bigelow Lab Ocean Sci, W Boothbay Harbor, ME 04575 USA. RP Neale, PJ (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. RI Cullen, John/B-6105-2008; Neale, Patrick/A-3683-2012 OI Cullen, John/0000-0002-7740-0999; NR 56 TC 96 Z9 97 U1 0 U2 2 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 1998 VL 43 IS 3 BP 433 EP 448 PG 16 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA ZU612 UT WOS:000074215500006 ER PT J AU Miriti, MN Howe, HE Wright, SJ AF Miriti, MN Howe, HE Wright, SJ TI Spatial patterns of mortality in a Colorado desert plant community SO PLANT ECOLOGY LA English DT Article DE demography; dispersion; intraspecific competition; shrubs ID SONORAN DESERT; TREE; FOREST; RECRUITMENT; COMPETITION; DISPERSION; DIVERSITY; DYNAMICS; ADULTS; GROWTH AB Spatial pattern and patterns of mortality were analyzed from a five year re-census of over 7 000 mapped perennial shrubs within a one hectare study plot in Joshua Tree National Park. A five year interval revealed evidence for negative intraspecific interactions which was not evident after a one year evaluation of the same plants within the study area. Juvenile mortality was a positive function of conspecific density for Ambrosia dumosa, Eriogonum fasciculatum and Sphaeralcea ambigua. In addition,juvenile E. fasciculatum that died occurred closer to conspecific adults than would be expected by chance. The two censuses are similar in that uniform patterns of distribution among conspecifics are rare, particularly for non-succulent species. These results emphasize the value of mapped study sites in allowing dynamic inferences from otherwise static analyses. Herbivory and nurse effects are implicated as potential factors influencing the dispersion of perennial plants within deserts. C1 Univ Illinois, Dept Biol Sci, Chicago, IL 60607 USA. Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. RP Miriti, MN (reprint author), Univ Illinois, Dept Biol Sci, M-C 066,845 W Taylor St, Chicago, IL 60607 USA. RI Wright, Stuart/M-3311-2013 OI Wright, Stuart/0000-0003-4260-5676 NR 32 TC 39 Z9 40 U1 0 U2 19 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 MAY PY 1998 VL 136 IS 1 BP 41 EP 51 DI 10.1023/A:1009711311970 PG 11 WC Plant Sciences; Ecology; Forestry SC Plant Sciences; Environmental Sciences & Ecology; Forestry GA ZR443 UT WOS:000073976100004 ER PT J AU Hunter, TR AF Hunter, TR TI A submillimeter imaging survey of ultracompact H II regions SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article C1 CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. RP Hunter, TR (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS-78, Cambridge, MA 02138 USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAY PY 1998 VL 110 IS 747 BP 634 EP 634 DI 10.1086/316163 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZM984 UT WOS:000073596200008 ER PT J AU Jarlemark, POJ Emardson, TR Johansson, JM AF Jarlemark, POJ Emardson, TR Johansson, JM TI Wet delay variability calculated from radiometric measurements and its role in space geodetic parameter estimation SO RADIO SCIENCE LA English DT Article; Proceedings Paper CT Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment CY NOV 04-06, 1996 CL BOSTON, MASSACHUSETTS ID BASE-LINE; RADIO; INTERFEROMETRY; TROPOSPHERE AB The "wet delay," the excess radio path length due to atmospheric water vapor, has been derived from 71 days of microwave radiometer measurements at the Onsala Space Observatory, Onsala, Sweden. The temporal and spatial variability in the wet delay was analyzed. When we estimated daily "variance rates," the parameter characterizing a random walk process, values in the range 3.1 x 10(-9) to 1.1 x 10(-7) m(2)/s were found for the timescales 10-20 min. We estimated horizontal gradients in the wet delay and found that the temporal variability of the gradient components changed significantly from day to day. The variations in the gradients were also found to be significantly larger if data acquired only at relatively high elevation angles were used in the calculation. The effect of the wet delay variations on Global Positioning System (GPS) geodetic estimates was analyzed by performing Monte Carlo simulations. We used a Kalman filter with parameters for geodetic GPS data processing, first modeling the atmosphere as a horizontally homogeneous random walk process in time. In this case the estimated wet delay was found to be more sensitive to a detuning of the Kalman filter than the vertical component estimates. The RMS errors in the wet delay estimates increased from 2.2 to 3.6 mm when the atmospheric variance rate changed from 1.0 x 10(-8) to 1.0 x 10(-7) m(2)/s and when the filter parameter was set to 1.0 x 10(-8) m(2)/s. When simulated wet delay gradients were added to the data, it was seen that if gradients are not estimated by the Kalman filter on days with large gradient variability, the scatter introduced by the gradients can dominate the other modeled error sources. C1 Chalmers Univ Technol, Onsala Space Observ, S-43992 Onsala, Sweden. RP Jarlemark, POJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 42, Cambridge, MA 02138 USA. NR 13 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAY-JUN PY 1998 VL 33 IS 3 BP 719 EP 730 DI 10.1029/98RS00551 PG 12 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA ZR645 UT WOS:000073999500023 ER PT J AU Bermingham, E Coates, A Cruz, G Emmons, L Foster, RB Leschen, R Seutin, G Thorn, S Wcislo, W Werfel, B AF Bermingham, E Coates, A Cruz, G Emmons, L Foster, RB Leschen, R Seutin, G Thorn, S Wcislo, W Werfel, B TI Geology and terrestrial flora and fauna of Cayos Cochinos, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE protected area; fauna and flora inventory; neotropics; reptiles; birds; mammals; insects ID HYMENOPTERA AB We conducted brief (3-5 day), preliminary surveys of the geology and terrestrial flora and fauna of Cayos Cochinos, Honduras over a three month period (March-May) in 1995. Our descriptions focused on Cayo Cochino Pequeno which is a fully protected island in the Reserva Biologica Cayos Cochinos, a recently created Honduran national park. Bird and mammal surveys complemented previous studies of the avian, reptile and amphibian vertebrate faunas. The species composition and distribution of plants and insects are described for the first time. The checklist of (160) vascular plant species includes all the common forest plants and a characterization of the different vegetation types. Insect diversity was low on Cayos Cochinos and representatives of nine families were collected. Fifteen species of amphibians (n=2) and reptiles (n=13) have been previously reported on the islands. We noted 43 species of birds on the main islands and adjacent small cays. Two small colonies of Brown Pelicans on Cayo Cochino Pequeno represent the first breeding record for the species on the Caribbean coast of Honduras. A small group of Royal Terns breeding on Cayo Gallina, a sand cay close to Cayo Cochino Pequeno, provide the first confirmation that this species is nesting in Honduras. We collected eight species of mammals and observed two more, one of which is a certain record (Agouti paca), while the other (Marmosa sp.) requires verification. The six bat species recorded were common at the time of our survey, some with extremely high densities (capture rates) relative to mainland populations. Our report closes with management and research recommendations for Cayos Cochinos. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Bermingham, E (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 32 TC 11 Z9 15 U1 0 U2 2 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 MAY PY 1998 VL 46 SU 4 BP 15 EP 37 PG 23 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300002 ER PT J AU D'Croz, L Jackson, JBC Best, MMR AF D'Croz, L Jackson, JBC Best, MMR TI Siliciclastic-carbonate transitions along shelf transects through the Cayos Cochinos Archipelago, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE Central American shelf; siliciclastic sediments; carbonate environments ID SEDIMENTS AB The Honduran Caribbean shelf possesses all of the conditions necessary for deposition of both carbonate and siliciclastic sediments within a relatively limited area. However, what is revealed in two cross shelf transects through the Cayos Cochinos Archipelago is not a simple shore to shelf edge gradual transition between siliciclastic and carbonate shelf environments. Rather there is lateral as well as cross-shelf variability, in addition to variability in the nature of the sediments within both the siliciclastic and carbonate settings. Strong terrestrial influence is restricted to a narrow nearshore siliciclastic belt less than 10 Km in width, with abundant organic-rich siliciclastic mud, and a low proportion of biogenic, predominantly molluscan, carbonate grains. At the outer edge of this belt, there is a transition zone of coarse siliciclastic sands that are likely the result of longshore transport. The mid and outer shelf areas have carbonate bottom sediments, where biogenic material is mostly derived from reef coral fragments and Halimeda flakes in varying proportions. Results from this study and others in the area indicate that the transition between siliciclastic and carbonate shelf environments is rather complex, with lateral and cross-shelf variability related to the effects from the freshwater discharge from rivers, the wind/wave-driven longshore currents, and the geomorphology and topography of the shelf. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP D'Croz, L (reprint author), Smithsonian Trop Res Inst, Box 2072, Balboa, Panama. NR 27 TC 3 Z9 3 U1 0 U2 2 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 MAY PY 1998 VL 46 SU 4 BP 57 EP 66 PG 10 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300004 ER PT J AU Guzman, HM AF Guzman, HM TI Diversity of stony, soft and black corals (Anthozoa : Scleractinia, Gorgonacea, Antipatharia; Hydrozoa : Milleporina) at Cayos Cochinos, Bay Islands, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE coral biodiversity; protected area; coral reefs ID MONTASTRAEA-ANNULARIS; COSTA-RICA; OCTOCORALLIA; RECORD AB The diversity of the coral fauna in all reef habitats down to 35 m depth at the Reserva Biologica Cayos Cochinos was determined from surveys conducted from August 1994 to June 1996. Sixty-six species of hermatypic corals (including three Millepora), forty-four species of octocorals, and five species of antipatharians are reported for this protected area. This increases the known species of corals in Honduras by ca. 40% and 91% for scleractinians and octocorals, respectively. These differences appear to be primarily a function of the extent of the survey at this location and taxonomic uncertainties across the region. Large-scale surveys in the Bay Islands will provide further insights into the diversity and ecology of reef corals across Central America. Little is known about the coral reefs of Honduras, and further work should be directed towards studying the ecology and management of these reefs. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, POB 2072, Balboa, Panama. NR 24 TC 3 Z9 6 U1 1 U2 3 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 MAY PY 1998 VL 46 SU 4 BP 75 EP 80 PG 6 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300006 ER PT J AU Jacome, G AF Jacome, G TI Checklist of Decapoda (Anomura, Brachyura), Cayos Cochinos Biological Reserve, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA Spanish DT Article DE Decapods; Anomuras; Brachyuras; crabs; conservation management; inventory AB Decapods (Anomura and Brachyura) were surveyed for 3 months in coral reefs, seagrass beds, beaches and terrestrial areas of the largest islands at the Cayos Cochinos Biological Reserve. A total of 45 species, within their families. were recorded including: Coenobitidae (1), Diogenidae (4) for Anomuras and for the Brachyura the Raninidae family (1 species), Calappidea (1), Leucossidae (1), Majidae (14), Portunidae (7), Xanthidae (7), Grapsidae (5), Gercarcinidae (2) and Ocypodidae (2). C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Jacome, G (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 22 TC 2 Z9 2 U1 0 U2 0 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 MAY PY 1998 VL 46 SU 4 BP 89 EP 93 PG 5 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300008 ER PT J AU Lessios, HA AF Lessios, HA TI Shallow water echinoids of Cayos Cochinos, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE sea urchins; biogeography; faunal lists; Caribbean; population density ID DIADEMA-ANTILLARUM; MASS MORTALITY; LYTECHINUS-VARIEGATUS; COMMUNITY STRUCTURE; REEF; ECHINODERMATA; HERBIVORY; DIVERSITY; URCHIN; PANAMA AB The following thirteen species were encountered in a survey of shallow water echinoids at Cayos Cochinos Biological Reserve, Honduras: Eucidaris tribuloides, Diadema antillarum, Arbacia punctulata, Lytechinus variegatus, Tripneustes ventricosus, Echinometra lucunter, E. viridis, Clypeaster rosaceus, Paraster doederleini, P. floridiensis, Brissopsis elongata, Brissus unicolor, and Meoma ventricosa. Characters for field identification of these species are given. Most of these species are common in many other areas of the Caribbean, but the presence of A. punctulata is noteworthy, because this species is often absent or very rare elsewhere in the tropical west Atlantic. Lytechinus williamsi, another echinoid with disjunct geographic distribution, appears to be absent at Cayos Cochinos. L. variegatus, normally abundant in Thalassia beds everywhere in the Caribbean, was very rare at Cayos Cochinos in 1995. Diadema antillarum was also rare; apparently at Cayos Cochinos, as in all other areas where its abundance has been monitored, it has not recovered from mass mortality that it suffered throughout the western Atlantic in 1983-1984. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Lessios, HA (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 21 TC 6 Z9 8 U1 0 U2 5 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 MAY PY 1998 VL 46 SU 4 BP 95 EP 101 PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300009 ER PT J AU Alvarez, MA AF Alvarez, MA TI Shallow water molluscs (Gastropoda y Pelecypoda) from Cayos Cochinos Biological Reserve, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA Spanish DT Article DE gastropods; bivalves; diversity; coral reefs; protected areas AB A preliminary study was done on the malacofauna of the protected area of Cayos Cochinos, Honduras, with the purpose of using it as a baseline for future projects. A total of 85 species of pelecipods and 106 species of gastropods are reported. This low diversity may reflect the fact that samples where only taken in shallow waters. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Alvarez, MA (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 4 TC 0 Z9 0 U1 0 U2 0 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 MAY PY 1998 VL 46 SU 4 BP 103 EP 107 PG 5 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300010 ER PT J AU Clifton, KE Clifton, LM AF Clifton, KE Clifton, LM TI A survey of fishes from various coral reef habitats within the Cayos Cochinos Marine Reserve, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE coral reef fishes; population census; abundance; density; diversity AB This paper describes reef fish populations within the recently established Cayos Cochinos Biological Reserve (November 1993), a small archipelago of islands and reefs lying 10 km north of the Honduran coast. After years of commercial exploitation, only subsistence-artisanal level hand-line fishing is now permitted in the Reserve. Three census methods (random swims, stationary counts, and transect surveys) were employed using SCUBA and snorkel to determine overall species richness and abundance within five habitat types (shallow Semi-protected reef; shallow exposed reef; shallow back reef comprising areas of grass, sand, and rubble; deep reef; and offshore reef). These, surveys revealed a diverse reef fish community, with a total of 226 species reported for the area. These data provide the first quantitative assessment of fish populations in the area and the necessary baseline information for subsequent studies in the preserve. The densities reported here suggest that historical fishing pressure has reduced the diversity and abundance of commercially important species, and has had and important impact upon various aspects of the reef community structure. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Clifton, KE (reprint author), Smithsonian Trop Res Inst, POB 2072, Balboa, Panama. NR 10 TC 5 Z9 6 U1 1 U2 7 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 MAY PY 1998 VL 46 SU 4 BP 109 EP 124 PG 16 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300011 ER PT J AU Tewfik, A Guzman, HM Jacome, G AF Tewfik, A Guzman, HM Jacome, G TI Distribution and abundance of the spiny lobster populations (Panulirus argus and P-guttatus) in Cayos Cochinos, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE Panulirus argus; Panulirus guttatus; spiny lobster; population assessment ID FLORIDA AB A study was conducted to gather baseline data on the present condition of the spiny lobster stocks within the Cayos Cochinos Archipielago using direct visual assessment techniques. Data collected would allow the initial estimate of total abundance and density of lobster species, as well as of the distribution of populations by habitat type and water depth, population structure by size/age category, collection and analysis of morphological parameters (carapace length, tail length, telson length and total weight), estimation of sex ratios, and observations on reproductive state. A total of 57 transects, covering 17004 m(2), were completed on SCUBA during the three-week study. Two species of spiny lobster were observed in 22 of the 57 transects (39%); 34 Panulirus argus and 16 Panulirus guttatus. Mean density of P. argus overall was 19.86 individuals/ha P. guttatus had a mean density overall of 9.35 individuals/ha P. argus showed increasing mean density with decreasing depth whereas P, guttatus showed an opposite trend with no individuals being recorded below 10 m. Linear regression analysis between various morphological parameters of P. argus all revealed strong correlations. The mean carapace length (73 mm) and tail length (127.4 mm) for P. argus were below the minimum legal tail length of 140 mm (5.5 inches) and the corresponding 80 mm carapace length. The sex ratio appeared to be one to one and mature individuals were found amongst both species. Despite the fact that the stocks appear overfished and illegal fishing activity does take place within the reserve, certain isolated small deep coral patches (sites 21, 26) and areas of rough surface conditions (site 23) have provided refugia for ongoing reproduction and recruitment. In order to provide further protection of existing stocks throughout Honduras and especially within the areas of the reserve where harvest is allowed, the following recommendations are given: (1) an absolute ban on the harvest of berried or spermatophore carrying females; (2) a distinction between P. argus and P. guttatus for minimum size regulations given that P. guttatus is harvested on an equal basis with P. argus by divers; and (3) the elimination of hooks (replaced by snares) to capture lobster in order to facilitate release and survival if undersized or berried. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 25 TC 7 Z9 7 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 MAY PY 1998 VL 46 SU 4 BP 125 EP 136 PG 12 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300012 ER PT J AU Tewfik, A Guzman, HM Jacome, G AF Tewfik, A Guzman, HM Jacome, G TI Assessment of the queen conch Strombus gigas (Gastropoda : Strombidae), population in Cayos Cochinos, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA English DT Article DE Strombus gigas; queen conch; population assessment; growth; reproduction; Honduras ID MORTALITY; GROWTH AB A visual preliminary assessment of the Strombus gigas population in the area of the Cayos Cochinos Biological Reserve was conducted by SCUBA divers swimming transects. Additional data on size/age structure, morphometries (shell length, shell width, shell lip thickness, and total weight), habitat, and reproductive activity were also collected. Size frequency distributions are given for shell length and shell lip thickness in an effort to reveal growth and age of the various cohorts. Linear regression analyses were conducted between various morphometric measurements. A total of 40 transects were completed covering a total area of 45504 m(2). The mean area of a transect was 1137.6 m(2) at a mean depth of 15.3 m. The overall density was calculated as being 14.6 conch/ha (S.D. = 36.15) over the study area of 15330 ha giving an approximate total abundance of 223818 conch. The majority (58.8%) of conch found in transects were found in depths of less than 10 m. A total of 177 conch were collected in and out of the transects with 48% juveniles and 52% adults. The population was further sub-divided into six categories for quick assessment during transects: four juvenile; small (0%), medium (10.7%), large (19.8%), sub-adult (17.5%): and two adult normal (27.1%), and stoned (24.9%). Reproductive activity included copulation, spawning, and solitary egg masses concentrated on seagrass slopes from five to 18 m in depth. New details on copulation were observed. It is felt that the low density and abundance is a direct result of 30 years of heavy exploitation by the Garifuna fishermen and commercial divers prior to the creation of the reserve. Future management measures should include the increase of the minimum shell length restriction to 240 mm, the use of a mature lip regulation, banning of SCUBA in fishing, and seasonal closures of important breeding areas. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 27 TC 13 Z9 14 U1 0 U2 11 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 MAY PY 1998 VL 46 SU 4 BP 137 EP 150 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300013 ER PT J AU Guzman, HM Jacome, G AF Guzman, HM Jacome, G TI Artisan fishery of Cayos Cochinos Biological Reserve, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA Spanish DT Article DE protected area; coral reefs; artisanal fishery; Ocyurus chrysurus ID REEF FISHES; CENTRAL BAHAMAS; CORAL-REEFS; MARINE; MANAGEMENT; PHILIPPINES; RECRUITMENT; ABUNDANCE; RESOURCE; ISLAND AB With the creation of the protected area of Cayos Cochinos, a five-year ban on lobster and conch fishing was implemented by the government of Honduras (started in November 1993). This study provides an initial assessment of the artisanal fishery carried out within the biological reserve exclusively by hook-and-line, and discuss potential influences of this activity on the recovery of the area. During 11 months, fish landings were monitored, through the analysis of a sample of 4959 fishes based on 365 questionnaires performed to fishermen, to evaluate the species composition, the weight and size of the most important species, the catch per unit effort (CPUE) and the yield from coral reefs within the protected area. The most common mean of transportation of fishermen is the canoes without engines (97%), providing a CPUE for the entire Reserve of 5.1 kg/fisher/day distributed in 37 species. About 80% of the total catch is represented by 8 species (mainly Lutjanidae, Serranidae and Haemulidae). It is concentrated in reef areas closely to the fishing villages (ca. 38% of the protected area). Dominant species caught was the yellow-tail snapper, Ocyurus chrysurus, with 53% of the total landings, apparently based on a 95% population of juvenile individuals (20-37 cm). We estimate, based on an average record of 23 canoes/day and our data of 2530 kg/month for fishing landings similar to 2930 kg/month recorded indirectly from fish-buyers located in the three villages, a fish yield for the reefs of 0.14 t/km(2)/year for the reefs inside Biological Reserve, highly comparable to overfished areas elsewhere. The results of the present study and the results from other studies on the visual abundance and diversity of fishes, queen conch and lobster in this area indicate that a high level of artisanal fishery exploitation exists within the protected area where the integrity of populations of commercial and cultural value species are being placed in danger. The current rate of exploitation of certain species, the high catch of immature juveniles, the low yield for this fishery, and the gradual degradation of natural habitats where important species reproduce and grow cannot continue if adequate levels of management is the goal. The existing fishing regulations have aimed to a positive reduction of the commercial vessel activities, nevertheless, it seems as if the impact of artisanal fishing has being underestimated within the Reserve and the collapse of certain species would be expected unless present regulations are improved. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 32 TC 1 Z9 1 U1 0 U2 10 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 MAY PY 1998 VL 46 SU 4 BP 151 EP 163 PG 13 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300014 ER PT J AU Guzman, HM Guevara, C AF Guzman, HM Guevara, C TI Massive mortality of zooxanthelate reef organisms during the 1995 bleaching in Cayos Cochinos, Honduras SO REVISTA DE BIOLOGIA TROPICAL LA Spanish DT Article DE protected area; Black Band Disease; warming; bleaching; coral reefs ID CORALS; REGENERATION; ECOSYSTEMS; EVENTS AB Coral reefs in Cayos Cochinos were affected during a severe bleaching event in 1995 associated with a 9-week (July-October) increase in sea surface temperature (>3.5 degrees C). All coral reefs within the 460 Km(2) Biological Reserve were initially surveyed during September. In October, three reef sites were selected to quantify the extent of the damage; healthy, bleaching and dead coral colonies were recorded in six-200 m(2) transects per reefs at two different depths. The bleaching event affected 73%, 92%, 97% and 95% of scleractinian corals, hydrocorals (Millepora spp.), zoathids (Palythoa spp.) and octocorals, respectively. At the time of the survey, the highest mortality was observed in Millepora with 74% of the colonies followed by Palythoa (12%), octocorals (8%) and scleractinian corals (6%). Whereas the number of totally dead colonies for scleractinian corals was low, all surviving colonies, mostly Montastraea spp. and Agaricia spp., showed extensive partial mortality within the colony, and fewer colonies partially recovered by the end of October. A second survey made in August 1996 at two of the previously surveyed sites showed a high number of dead coral colonies (83%). The bleaching event of 1995 appears to have triggered an infection of Black Band Disease; 34% of the colonies (Montastraea annularis y M. faveolata) were infected, further increasing partial mortality of the colonies. The long-term impact of this event on the artisinal fishery remains to be evaluated and it is predicted changes in stocks abundance of commercially important species due to the lost of reef habitats associated with this natural event. Managers at the Biological Reserve should consider the creation of new restricted fishing zones within the protected area, including new fishing restrictions to allow reef recovery and stock enhancement of valuable species. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 19 TC 4 Z9 4 U1 2 U2 5 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 MAY PY 1998 VL 46 SU 4 BP 165 EP 173 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300015 ER PT J AU Guzman, HM AF Guzman, HM TI Cayos Cochinos, Honduras: Where to go? SO REVISTA DE BIOLOGIA TROPICAL LA English DT Editorial Material C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Guzman, HM (reprint author), Smithsonian Trop Res Inst, Balboa, Panama. NR 0 TC 0 Z9 0 U1 0 U2 1 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 MAY PY 1998 VL 46 SU 4 BP U1 EP U2 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZQ434 UT WOS:000073861300001 ER PT J AU Alroy, J AF Alroy, J TI Cope's rule and the dynamics of body mass evolution in North American fossil mammals SO SCIENCE LA English DT Article ID ISLAND RULE; SIZE; PHYLOGENY; TRENDS; RECORD AB Body mass estimates for 1534 North American fossil mammal species show that new species are on average 9.1% larger than older species in the same genera. This within-lineage effect is not a sampling bias. It persists throughout the Cenozoic; accounting for the gradual overall increase in average mass (Cope's rule). The effect is stronger for larger mammals, being near zero for small mammals. This variation partially explains the unwavering lower size limit and the gradually expanding mid-sized gap, but not the sudden large increase in the upper size limit, at the Cretaceous-Tertiary boundary. C1 Smithsonian Inst, Dept Paleobiol, Washington, DC 20560 USA. RP Alroy, J (reprint author), Smithsonian Inst, Dept Paleobiol, MRC 121, Washington, DC 20560 USA. RI Alroy, John/B-4585-2009 NR 48 TC 270 Z9 277 U1 9 U2 76 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 1 PY 1998 VL 280 IS 5364 BP 731 EP 734 DI 10.1126/science.280.5364.731 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZL268 UT WOS:000073415600046 PM 9563948 ER PT J AU DePriest, P AF DePriest, P TI Aaron John ('Jack') Sharp (1904-1997) SO TAXON LA English DT Biographical-Item C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Bot MRC 166, Washington, DC 20560 USA. RP DePriest, P (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Bot MRC 166, Washington, DC 20560 USA. RI DePriest, Paula/K-6633-2015 NR 0 TC 0 Z9 0 U1 0 U2 1 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 MAY PY 1998 VL 47 IS 2 BP 519 EP 519 PG 1 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA ZQ295 UT WOS:000073843600023 ER PT J AU Nicolson, DH AF Nicolson, DH TI R. S. Cowan (1921-1997) SO TAXON LA English DT Biographical-Item C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Bot MRC 166, Washington, DC 20560 USA. RP Nicolson, DH (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Bot MRC 166, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 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 MAY PY 1998 VL 47 IS 2 BP 520 EP 530 PG 11 WC Plant Sciences; Evolutionary Biology SC Plant Sciences; Evolutionary Biology GA ZQ295 UT WOS:000073843600024 ER PT J AU Wcislo, WT Danforth, BN AF Wcislo, WT Danforth, BN TI Eusociality, life underground and parasites - Reply SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Letter C1 Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. Cornell Univ, Dept Entomol, Ithaca, NY 14853 USA. RP Wcislo, WT (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD MAY PY 1998 VL 13 IS 5 BP 199 EP 199 DI 10.1016/S0169-5347(98)01353-6 PG 1 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA ZJ908 UT WOS:000073265800011 PM 21238262 ER PT J AU Gladman, BJ Nicholson, PD Burns, JA Kavelaars, JJ Marsden, BG Williams, GV Offutt, WB AF Gladman, BJ Nicholson, PD Burns, JA Kavelaars, JJ Marsden, BG Williams, GV Offutt, WB TI Discovery of two distant irregular moons of Uranus SO NATURE LA English DT Article ID SMALL SATELLITES; KUIPER BELT; PHOTOMETRY AB The systems of satellites and rings surrounding the giant planets in the Solar System have remarkably similar architectures(1) Closest to each planet are rings with associated moonlets, then larger 'regular' satellites on nearly circular orbits close to the planet's equatorial plane, and finally one or more distant, small 'irregular' satellites on highly elliptical or inclined orbits. Hitherto, the only departure from this broad classification scheme was the satellite system around Uranus, in which no irregular satellites had been found(2). Here we report the discovery of two satellites orbiting Uranus at distances of several hundred planetary radii. These satellites have inclined, retrograde orbits of moderate eccentricity that clearly identify them as irregular. The satellites are extremely faint (apparent red magnitudes m(R) = 20.4 and 21.9), with estimated radii of only 60 and 30 km. Both moons are unusually red in colour, suggesting a link between these objects-which were presumably captured by Uranus early in the Solar System's history-and other recently discovered bodies(3) orbiting in the outer Solar System. C1 Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. W&B Observ, Cloudcroft, NM 88317 USA. RP Gladman, BJ (reprint author), Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. NR 34 TC 50 Z9 51 U1 0 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 30 PY 1998 VL 392 IS 6679 BP 897 EP 899 DI 10.1038/31890 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZK759 UT WOS:000073359900040 ER PT J AU Gotz, M AF Gotz, M TI Validity of the 'conservation law' in the evolution of cosmological perturbations SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE cosmology, theory; large-scale structure of Universe AB It is shown that the 'conservation law' for metric fluctuations with long wavelengths is indeed applicable for growing modes of perturbations, which are of interest in cosmology, in spite of recent criticism. This is demonstrated both by general arguments and by presenting an explicitly solvable toy model for the evolution of metric perturbations during inflation. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Brown Univ, Dept Phys, Providence, RI 02912 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS-20, Cambridge, MA 02138 USA. EM mgotz@cfa.harvard.edu NR 8 TC 1 Z9 1 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 21 PY 1998 VL 295 IS 4 BP 873 EP 876 DI 10.1046/j.1365-8711.1998.01290.x PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZK961 UT WOS:000073385000016 ER PT J AU Hasan, SS Kneer, F Kalkofen, W AF Hasan, SS Kneer, F Kalkofen, W TI Spectral line radiation from solar small-scale flux tubes. II SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun : magnetic fields; Sun : photosphere ID EQUILIBRIUM STRUCTURE; MAGNETIC ELEMENTS; INVERSION; POINTS; MODELS AB We examine spectral line radiation from small-scale magnetic flux tubes in the solar atmosphere. This is a continuation of work by Kneer et al. (1996). The main difference with the previous investigation is in the choice of the external atmosphere. Earlier we adopted an atmosphere resembling the empirical quiet Sun model for the ambient medium. In the present study, we iteratively adjust the temperature structure of the external atmosphere to fit the Stokes I and V profiles and the average continuum intensities with those obtained from observations. Our models are hotter in the uppermost photospheric layers and cooler in the deeper layers than the quiet Sun model and agree well with semi-empirical flux tube models. C1 Univ Sternwarte, D-37083 Gottingen, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Indian Inst Astrophys, Bangalore 560034, Karnataka, India. RP Kneer, F (reprint author), Univ Sternwarte, Geismarlandstr 11, D-37083 Gottingen, Germany. RI Hasan, Siraj/C-2927-2012 NR 24 TC 7 Z9 7 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 20 PY 1998 VL 332 IS 3 BP 1064 EP 1068 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZL736 UT WOS:000073465300033 ER PT J AU Wahlgren, GM Evans, NR AF Wahlgren, GM Evans, NR TI A HgMn companion to the cepheid SU Cyg SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE stars : abundances; stars : chemically peculiar; binaries : spectroscopic; variables : Cepheids ID CHEMICALLY PECULIAR STARS; CHI-LUPI; MAIN-SEQUENCE; OPEN CLUSTERS; ABUNDANCES; ANOMALIES; BINARIES; MASS AB We report here the discovery of a chemically peculiar star of the HgMn type as a companion to the classical Cepheid variable SU Cyg. This is the first investigation of a HgMn star in a binary system in which a star of a more advanced evolutionary stage is the primary. The age of the Cepheid provides an estimate to the age of the chemical peculiarities which is independent of the photometric calibration of HgMn field stars. From a synthetic spectrum analysis it is determined that the HgMn star, SU Cyg B, displays the abundance deficiency for nitrogen and enhancements for manganese (+1.5 dex) and the very heavy elements mercury (+5.8 dex) and platinum (+5.0 dex). Absorption from the strong transitions Au II lambda 1740 and Tl II lambda 1908 each implies abundance enhancements of 3.0 dex. A search through the IUE and HST/GHRS spectral archives reveals several binary-Cepheid companions which are candidates for chemically peculiar stars. C1 Univ Lund, Dept Phys, Atom Spect Grp, S-22362 Lund, Sweden. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Wahlgren, GM (reprint author), Univ Lund, Dept Phys, Atom Spect Grp, Solvegatan 14, S-22362 Lund, Sweden. EM spek_glenn@garbo.lucas.lu.se; nevans@head-cfa.harvard.edu NR 20 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 APR 20 PY 1998 VL 332 IS 3 BP L33 EP L36 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZL736 UT WOS:000073465300002 ER PT J AU Kim, DW Fabbiano, G Mackie, G AF Kim, DW Fabbiano, G Mackie, G TI ROSAT X-ray observations of the radio galaxy NGC 1316 (Fornax A) SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (NGC 1316); galaxies, ISM; galaxies, jets; X-rays, galaxies ID CCD SURFACE PHOTOMETRY; IC-4296 PKS 1333-33; PSPC OBSERVATIONS; ELLIPTICAL GALAXIES; INTERSTELLAR MATTER; SPECTRAL PROPERTIES; COMPLETE SAMPLE; EMITTING GAS; HOT GAS; H-ALPHA AB We have observed NGC 1316 (Fornax A) with the ROSAT HRI. In this paper, we present the results of these observations and complement them with the spectral analysis of the archival PSPC data. The spectral properties suggest the presence of a significant component of thermal X-ray emission (greater than 60%), amounting to similar to 10(9) M. of hot interstellar matter (ISM). Within 3' from the nucleus of NGC 1316, the HRI X-ray surface brightness falls as r(-2). In the inner similar to 40 ", the X-ray surface brightness is significantly elongated (epsilon similar to 0.3). This flattened X-ray feature is confirmed by a straightforward statistics test as well as moment analysis. By comparing the morphology of the X-ray emission with the distribution of optical dust patches, we find that the X-ray emission is significantly reduced at the locations where the dust patches are more pronounced, indicating that at least some of the X-ray photons are absorbed by the cold ISM. We also compare the distribution of the hot and cold ISM with that of the ionized gas, using recently obtained H alpha CCD data. We iind that the ionized gas is distributed roughly along the dust patches and follows the large-scale X-ray distribution at r > 1' from the nucleus. However, there is no one-to-one correspondence between ionized gas and hot gas. Both morphological relations and kinematics suggest different origins for hot and cold ISM. The radio jets in projection appear to pass perpendicularly through the central X-ray ellipsoid. Comparison of thermal and radio pressures suggests that the radio jets are confined by the surrounding hot gaseous medium. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Chungnam Natl Univ, Taejon 305764, South Korea. RP Kim, DW (reprint author), Chungnam Natl Univ, Taejon 305764, South Korea. NR 65 TC 23 Z9 23 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1998 VL 497 IS 2 BP 699 EP 712 DI 10.1086/305476 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZJ199 UT WOS:000073189400019 ER PT J AU Harwit, M Neufeld, DA Melnick, GJ Kaufman, MJ AF Harwit, M Neufeld, DA Melnick, GJ Kaufman, MJ TI Thermal water vapor emission from shocked regions in Orion SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared, ISM, lines and bands; ISM, abundances; ISM, individual (Orion); ISM, molecules; molecular processes ID MOLECULAR LINE EMISSION; NEBULA; KL; CO; WAVES; OH AB Using the Long Wavelength Spectrometer on board the Infrared Space Observatory, we have observed thermal water vapor emission from a roughly circular field of view approximately 75 " in diameter centered on the Orion BN-KL region. The Fabry-Perot line strengths, line widths, and spectral line shifts observed in eight transitions between 71 and 125 mu m show good agreement with models of thermal emission arising from a molecular cloud subjected to a magnetohydrodynamic C-type shock. Both the breadth and the relative strengths of the observed lines argue for emission from a shock rather than from warm quiescent gas in the Orion core. Although one of the eight transitions appears anomalously strong and may be subject to the effects of radiative pumping, the other seven indicate an H2O/H-2 abundance ratio on the order of 5 X 10(-4) and a corresponding gas-phase oxygen-to-hydrogen abundance ratio on the order of 4 X 10(-4). Given current estimates of the interstellar, gas-phase, oxygen and carbon abundances in the solar vicinity, this value is consistent with theoretical shock models that predict the conversion into water of all the gas-phase oxygen that is not bound as CO. The overall cooling provided by rotational transitions of H2O in this region appears to be comparable to the cooling through rotational lines of CO but is an order of magnitude lower than cooling through H-2 emission. However, the model that best fits our observations shows cooling by H2O and CO dominant in that portion of the postshock region where temperatures are below similar to 800 K and neither vibrational nor rotational radiative cooling by H-2 is appreciable. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Harwit, M (reprint author), 511 H St SW, Washington, DC 20024 USA. NR 25 TC 86 Z9 86 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1998 VL 497 IS 2 BP L105 EP L108 DI 10.1086/311291 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZJ200 UT WOS:000073189500012 ER PT J AU Herrnstein, JR Greenhill, LJ Moran, JM Diamond, PJ Inoue, M Nakai, N Miyoshi, M AF Herrnstein, JR Greenhill, LJ Moran, JM Diamond, PJ Inoue, M Nakai, N Miyoshi, M TI VLBA continuum observations of NGC 4258: Constraints on an advection-dominated accretion flow SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies, active; galaxies, individual (NGC 4258); galaxies, nuclei; masers ID SPIRAL GALAXY NGC-4258; ACTIVE GALACTIC NUCLEI; MOLECULAR DISK; BLACK-HOLES; SPECTRUM; JETS AB We report a 3 sigma upper limit of 220 mu Jy on any 22 GHz continuum emission coincident with the central engine in NGC 4258. If NGC 4258 is powered by an advection-dominated accretion flow, this radio upper limit implies that the inner advection-dominated flow cannot extend significantly beyond similar to 10(2) Schwarzschild radii. C1 Natl Radio Astron Observ, Socorro, NM 87801 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Astron Observ, Nobeyama Radio Observ, Minamimaki, Nagano 38413, Japan. Natl Astron Observ, Mizusawa Astrogeodynam Observ, Mizusawa, Iwate 023, Japan. RP Herrnstein, JR (reprint author), Natl Radio Astron Observ, POB O,1003 Lopezville, Socorro, NM 87801 USA. OI Moran, James/0000-0002-3882-4414 NR 27 TC 41 Z9 41 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1998 VL 497 IS 2 BP L69 EP L73 DI 10.1086/311284 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZJ200 UT WOS:000073189500004 ER PT J AU Timmermans, E Cote, R AF Timmermans, E Cote, R TI Superfluidity in sympathetic cooling with atomic Bose-Einstein condensates SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCATTERING; STATES AB The dynamical structure of an atomic Bose-Einstein condensate limits the efficiency of the condensate in cooling slow impurity atoms. To illustrate the point, we show that an impurity atom moving in a homogeneous zero-temperature condensate is not scattered incoherently if its velocity is lower than the condensate sound velocity c, limiting cooling to velocities v greater than or equal to c. This striking effect is an expression of superfluidity and provides a direct means to detect the fundamental property of superfluidity in atomic condensates. Furthermore, we show that the fermionic lithium isotope, Li-6, is a reasonable candidate for sympathetic cooling by a Na-23 condensate. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Timmermans, E (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. NR 26 TC 82 Z9 83 U1 0 U2 2 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 20 PY 1998 VL 80 IS 16 BP 3419 EP 3423 DI 10.1103/PhysRevLett.80.3419 PG 5 WC Physics, Multidisciplinary SC Physics GA ZJ325 UT WOS:000073202700001 ER PT J AU Wells, JC Simbotin, I Gavrila, M AF Wells, JC Simbotin, I Gavrila, M TI Physical reality of light-induced atomic states SO PHYSICAL REVIEW LETTERS LA English DT Article ID ABOVE-THRESHOLD-IONIZATION; INTENSE LASER FIELDS; MULTIPHOTON PROCESSES; HARMONIC-GENERATION; SHADOW POLES; SCATTERING; HYDROGEN; PULSES; RESONANCES AB The physical reality of light-induced states in atoms has remained uncertain, ever since their discovery by Floquet theory. We now show that their existence is confirmed by time-dependent wave packet theory, and should manifest itself experimentally. By applying a realistic pulse to the atomic system, and calculating the energy spectrum of the ionized electrons, we find signals at the energies predicted by Floquet theory for the light-induced states, sometimes with towering intensity. Choosing the initial states such as to connect to the light-induced states via diabatic Floquet paths substantially enhances the yield. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. FOM, Inst Atom & Mol Phys, NL-1098 SJ Amsterdam, Netherlands. RP Wells, JC (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RI Wells, Jack/D-3675-2016 OI Wells, Jack/0000-0002-5083-3030 NR 24 TC 24 Z9 24 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 20 PY 1998 VL 80 IS 16 BP 3479 EP 3482 DI 10.1103/PhysRevLett.80.3479 PG 4 WC Physics, Multidisciplinary SC Physics GA ZJ325 UT WOS:000073202700015 ER PT J AU McKeegan, KD Leshin, LA Russell, SS MacPherson, GJ AF McKeegan, KD Leshin, LA Russell, SS MacPherson, GJ TI Oxygen isotopic abundances in calcium-aluminum-rich inclusions from ordinary chondrites: Implications for nebular heterogeneity SO SCIENCE LA English DT Article ID SOLAR NEBULA; CARBONACEOUS CHONDRITES; ALLENDE INCLUSIONS; METEORITES; ORIGIN; COMPONENT; ANOMALIES; AL-26 AB The oxygen isotopic compositions of two calcium-aluminum-rich inclusions (CAIs) from the unequilibrated ordinary chondrite meteorites Quinyambie and Semarkona are enriched in (16)O by an amount similar to that in CAIs from carbonaceous chondrites. This may indicate that most CAIs formed in a restricted region of the solar nebula and were then unevenly distributed throughout the various chondrite accretion regions. The Semarkona CAI is isotopically homogeneous and contains highly (16)O-enriched melilite, supporting the hypothesis that all CAI minerals were originally (16)O-rich, but that in most carbonaceous chondrite inclusions some minerals exchanged oxygen isotopes with an external reservoir following crystallization. C1 Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Smithsonian Inst, Museum Natl Hist Nat, Dept Mineral Sci, Washington, DC 20560 USA. RP McKeegan, KD (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. EM kdm@ess.ucla.edu RI McKeegan, Kevin/A-4107-2008; UCLA, SIMS/A-1459-2011 OI McKeegan, Kevin/0000-0002-1827-729X; NR 39 TC 86 Z9 87 U1 3 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 APR 17 PY 1998 VL 280 IS 5362 BP 414 EP 418 DI 10.1126/science.280.5362.414 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZH907 UT WOS:000073159600041 PM 9545215 ER PT J AU Gingerich, O AF Gingerich, O TI Edmond Halley: Charting the Heavens and the seas SO NATURE 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 2 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 16 PY 1998 VL 392 IS 6677 BP 669 EP 670 DI 10.1038/33584 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZH612 UT WOS:000073129000042 ER PT J AU Seideman, T Kharchenko, V AF Seideman, T Kharchenko, V TI Two-dimensional scattering of slow molecules by laser beams SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ATOMS; PARTICLES; TRAP AB Quantum-mechanical and quasiclassical scattering of molecules in a nonperturbative laser field are studied. Analytical expressions for the observables of interest in laser-induced focusing and guiding of molecules are derived that span the quantal-to-classical energy regime and the weak-to-strong interaction range. General conclusions regarding the problem of two-dimensional quantum-mechanical scattering are drawn. (C) 1998 American Institute of Physics. [S0021-9606(98)01713-9]. C1 Natl Res Council Canada, Steacie Inst Mol Sci, Ottawa, ON K1A 0R6, Canada. Harvard Univ, Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. RP Seideman, T (reprint author), Natl Res Council Canada, Steacie Inst Mol Sci, 100 Sussex Dr, Ottawa, ON K1A 0R6, Canada. NR 36 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1998 VL 108 IS 15 BP 6272 EP 6281 DI 10.1063/1.476034 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZH114 UT WOS:000073073700023 ER PT J AU Kalfatovic, MR AF Kalfatovic, MR TI Random harvest. 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 APR 15 PY 1998 VL 123 IS 7 BP 94 EP 94 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA ZH489 UT WOS:000073116200114 ER PT J AU Balakrishnan, N Forrey, RC Dalgarno, A AF Balakrishnan, N Forrey, RC Dalgarno, A TI Quenching of H-2 vibrations in ultracold He-3 and He-4 collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID ENERGY SURFACE; RELAXATION; MOLECULES; BEHAVIOR; RATES AB We present results of quantum mechanical scattering calculations including full rovibrational coupling on the relaxation of vibrationally excited H-2 molecules in collision with ultracold He-3 and He-4 atoms. The exothermic vibrational deactivation cross sections exhibit minima at translational temperatures near 10 K and show an inverse velocity dependence in accordance with Wigner's threshold law in the limit of zero kinetic energy. The corresponding rate coefficients exhibit minima before attaining constant values below 10(-3) K. The rate coefficients increase by 3 orders of magnitude when the initial vibrational level of the molecule is raised from v = 1 to v = 10. The results suggest that quasibound resonance states of (HeH2)-He-3 and (HeH2)-He-4 exist, associated with each excited vibrational state of H-2, and that both the triatomic species (HeH2)-He-3 and (HeH2)-He-4 have one bound vibrational state. 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 27 TC 137 Z9 137 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 13 PY 1998 VL 80 IS 15 BP 3224 EP 3227 DI 10.1103/PhysRevLett.80.3224 PG 4 WC Physics, Multidisciplinary SC Physics GA ZG567 UT WOS:000073016600016 ER PT J AU Verdes-Montenegro, L Yun, MS Perea, J Del Olmo, A Ho, PTP AF Verdes-Montenegro, L Yun, MS Perea, J Del Olmo, A Ho, PTP TI Effects of interaction-induced activities in Hickson compact groups: CO and far-infrared study SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, abundances; galaxies, clusters, general; infrared, galaxies; ISM, molecules ID STAR-FORMATION RATES; EARLY-TYPE GALAXIES; SPIRAL GALAXIES; MOLECULAR GAS; VIRGO CLUSTER; IRAS OBSERVATIONS; STATISTICAL-METHODS; ELLIPTIC GALAXIES; GLOBAL PROPERTIES; ASTRONOMICAL DATA AB A study of 2.6 mm CO J = 1 --> 0 and far-infrared (FIR) emission in a distance-limited (z < 0.03) complete sample of Hickson compact group (HCG) galaxies was conducted in order to examine the effects of their unique environment on the interstellar medium of component galaxies and to search for a possible enhancement of star formation and nuclear activity. Ubiquitous tidal interactions in these dense groups would predict enhanced activities among the HCG galaxies compared to isolated galaxies. Instead, their CO and FIR properties (thus, "star formation efficiency") are surprisingly similar to isolated spirals. The CO data for 80 HCG galaxies presented here (including 10 obtained from the literature) indicate that the spirals globally show the same H-2, content as the isolated comparison sample, although 20% are deficient in CO emission. Because of their large optical luminosity, low metallicity is not likely the main cause for the low CO luminosity. The CO deficiency appears linked with the group evolution, and gas exhaustion through past star formation and removal of the external gas reserve by tidal stripping of the outer H I disk offer a possible explanation. The IRAS data for the entire redshift-limited complete sample of 161 HCG galaxies were reanalyzed using ADDSCAN/SCANPI, improving the sensitivity by a factor of 3-5 over the existing Point Source Catalog (PSC) and resolving better the contribution from individual galaxies. The new analysis of the IRAS data confirms the previous suggestion that FIR emission in HCG galaxies is similar to isolated, Virgo Cluster, and weakly interacting galaxies. Their H-2 and FIR characteristics yield a star formation efficiency that is similar to that of these comparison samples. A factor 2 enhancement in the 25-100 mu m flux ratio among the HCG spirals is found, which suggests intense localized nuclear starburst activity similar to that of H II galaxies. A number of early-type galaxies in HCGs are detected in CO and FIR, lending further support to the idea that tidal interactions and tidally induced evolution of the groups and member galaxies are important in our sample. C1 CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Natl Radio Astron Observ, Socorro, NM 87801 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Verdes-Montenegro, L (reprint author), CSIC, Inst Astrofis Andalucia, Apdo 3004, E-18080 Granada, Spain. RI del Olmo, Ascension/L-5045-2014 OI del Olmo, Ascension/0000-0003-2055-9816 NR 69 TC 73 Z9 73 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1998 VL 497 IS 1 BP 89 EP 107 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG883 UT WOS:000073049600011 ER PT J AU Mahdavi, A Kenyon, SJ AF Mahdavi, A Kenyon, SJ TI The bright accretion rings on magnetic T Tauri stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars, magnetic fields; stars, pre-main-sequence ID YOUNG STELLAR OBJECTS; MAGNETOCENTRIFUGALLY DRIVEN FLOWS; X-RAY SOURCES; DISK ACCRETION; CIRCUMSTELLAR DISKS; INTERMEDIATE POLARS; RADIAL-VELOCITIES; NEUTRON STARS; LIGHT CURVES; MASS-LOSS AB We model the properties of bright rings on accreting classical T Tauri stars whose magnetospheres are tilted with respect to the axis of rotation. These rings have interesting geometries and azimuthal intensity profiles depending on beta, the inclination angle of the dipole field, xi, the ratio of the star's radius to the accretion radius, and epsilon, the ratio of the star's luminosity to the total ring luminosity. As the star rotates, the rings may be occulted periodically, and the apparent brightness of the star may vary as a function of time. With knowledge of i, the observer's inclination, it is possible to predict Delta m, the amplitude of magnitude variations due to the occultation. Conversely, measurements of Delta m and either i or epsilon can constrain the values of the other variables. To observe any variation i must be greater than zero. Stars viewed nearly pole-on (i approximate to 10 degrees) must have beta greater than or similar to 50 degrees to allow any significant variation. On the other hand, with i greater than or similar to 60 degrees, even a very small beta approximate to 5 degrees can produce a significant Delta m. We find that stars that are as bright as their accretion rings (epsilon approximate to 1) cannot produce variations greater than approximate to 0.8 mag; to observe 2 mag variations epsilon approximate to 0.1 is required, independently of i or beta. We predict a distribution of Delta m that is consistent with observed populations of T Tauri stars in the Orion Nebula and in the Taurus-Auriga Molecular Cloud. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA USA. RP Mahdavi, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA USA. OI Kenyon, Scott/0000-0003-0214-609X NR 56 TC 36 Z9 36 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1998 VL 497 IS 1 BP 342 EP 353 DI 10.1086/305443 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG883 UT WOS:000073049600028 ER PT J AU Wood, K Kenyon, SJ Whitney, B Turnbull, M AF Wood, K Kenyon, SJ Whitney, B Turnbull, M TI Optical and near-infrared model images of the circumstellar environments of classical T Tauri stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; radiative transfer; stars, individual (HH 30); stars, pre-main-sequence ID YOUNG STELLAR OBJECTS; SPECTRAL ENERGY-DISTRIBUTIONS; AXISYMMETRICAL DUST CLOUDS; MAGNETIC NEUTRON STARS; AURIGA MOLECULAR CLOUD; HERBIG AE/BE STARS; SCATTERING ENVELOPES; ACCRETION DISKS; ROTATING PROTOSTARS; MULTIPLE-SCATTERING AB We describe model calculations of optical and near-infrared scattered light images expected from class II T Tauri stars-the star-plus-disk systems. The parameters controlling the disk shape, size, and mass are chosen to be within theoretically and observationally derived limits. We restrict our models to nearly edge-on disks, since for lower inclinations the central starlight is many orders of magnitude greater than the radiation scattered in the disk. In addition to model flux images, we calculate spectral energy distributions for pole-on viewing using approximations for hat and flared disks. We find that direct imaging of edge-on disks can provide only estimates of the scale height at large distances from the central star and an estimate of the disk mass. The images are rather insensitive to the inner disk radius and the degree of Baring, provided the scale height is axed at large radii. Spectral energy distribution modeling is required to constrain the inner disk radius and the degree of flaring. We apply our models to recent Hubble Space Telescope (HST) images of HH 30 IRS and investigate whether the scattered light images could have been produced by starlight scattering off the walls of jet-carved cavities in infalling envelopes associated with the embedded class I sources. We find that while the class I infalling envelope plus cavity model qualitatively resembles the HST images, the spatial extent of the model images is too large. Edge-on disk models appear to provide better fits to the data and enable us to determine the disk scale height at large distances from the central star. However, the assumption of axisymmetry and uniform illumination is clearly inadequate for this variable source. In addition to producing flux images, our radiation-transfer simulations predict the spatially resolved polarization structure of HH 30. We have also performed k'-band simulations for HH 30 in anticipation of high-resolution infrared imaging polarimetry. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Wisconsin Small Business Dev Ctr, Madison, WI 53706 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. RP Wood, K (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. OI Kenyon, Scott/0000-0003-0214-609X NR 64 TC 58 Z9 58 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1998 VL 497 IS 1 BP 404 EP 418 DI 10.1086/305449 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG883 UT WOS:000073049600032 ER PT J AU Sari, R Piran, T Narayan, R AF Sari, R Piran, T Narayan, R TI Spectra and light curves of gamma-ray burst afterglows SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, bursts; hydrodynamics; relativity; shock waves AB The recently discovered gamma-ray burst afterglow is believed to be described reasonably well by synchrotron emission from a decelerating relativistic shell that collides with an external medium. To compare theoretical models with afterglow observations, we calculate here the broadband spectrum and corresponding light curve of synchrotron radiation from a power-law distribution of electrons in an expanding relativistic shock. Both the spectrum and the light curve consist of several power-law segments with related indices. The light curve is constructed under two limiting models for the hydrodynamic evolution of the shock: fully adiabatic and fully radiative. We give explicit relations between the spectral index and the temporal power-law index. Future observations should be able to distinguish between the possible behaviors and determine the type of solution. C1 Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Sari, R (reprint author), Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. OI Narayan, Ramesh/0000-0002-1919-2730 NR 22 TC 984 Z9 999 U1 0 U2 17 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1998 VL 497 IS 1 BP L17 EP L20 DI 10.1086/311269 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG884 UT WOS:000073049700005 ER PT J AU Neale, PJ Davis, RF Cullen, JJ AF Neale, PJ Davis, RF Cullen, JJ TI Interactive effects of ozone depletion and vertical mixing on photosynthesis of Antarctic phytoplankton SO NATURE LA English DT Article ID BIOLOGICAL WEIGHTING FUNCTION; ULTRAVIOLET-RADIATION; MARINE-PHYTOPLANKTON; SOUTHERN-OCEAN; INHIBITION; WATERS; IMPACT; GROWTH; RATES; MODEL AB Photosynthesis of Antarctic phytoplankton is inhibited by ambient ultraviolet (UV) radiation during incubations(1-4), and the inhibition is worse in regions beneath the Antarctic ozone 'hole'(4). But to evaluate such effects, experimental results on, and existing models of, photosynthesis(5-7) cannot be extrapolated directly to the conditions of the open waters of the Antarctic because vertical mixing of phytoplankton alters UV exposure and has significant effects on the integrated inhibition through the water column(2,8,9). Here we present a model of UV-influenced photosynthesis in the presence of vertical mixing, which we constrain with comprehensive measurements from the Weddell-Scotia Confluence during the austral spring of 1993. Our calculations of photosynthesis integrated through the water column (denoted PT) show that photosynthesis is strongly inhibited by near-surface UV radiation, This inhibition can be either enhanced or decreased by vertical mixing, depending on the depth of the mixed layer, Predicted inhibition is most severe when mixing is rapid, extending to the lower part of the photic zone. Our analysis reveals that an abrupt 50% reduction in stratospheric ozone could, in the worst case, lower P-T by as much as 8.5%, However, stronger influences on inhibition can come from realistic changes in vertical mixing (maximum effect on P-T of about +/-37%), measured differences in the sensitivity of phytoplankton to UV radiation (+/-46%) and cloudiness (+/-15%). C1 Dalhousie Univ, Dept Oceanog, Ctr Environm Observat Technol & Res, Halifax, NS B3H 4J1, Canada. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Cullen, JJ (reprint author), Dalhousie Univ, Dept Oceanog, Ctr Environm Observat Technol & Res, Halifax, NS B3H 4J1, Canada. RI Cullen, John/B-6105-2008; Neale, Patrick/A-3683-2012 OI Cullen, John/0000-0002-7740-0999; NR 30 TC 201 Z9 207 U1 1 U2 24 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 9 PY 1998 VL 392 IS 6676 BP 585 EP 589 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZG300 UT WOS:000072987200054 ER PT J AU Lessios, HA Kessing, BD Robertson, DR AF Lessios, HA Kessing, BD Robertson, DR TI Massive gene flow across the world's most potent marine biogeographic barrier SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE Echinothrix diadema; Eastern Pacific Barrier; mtDNA; isozymes; vicariance; biogeography ID TROPICAL EASTERN PACIFIC; CLIPPERTON ATOLL; EL-NINO; DISPERSAL; CORALS; POPULATIONS; DISTANCE; OCEAN AB The 'Eastern Pacific Barrier' (EPB), 5400 km of uninterrupted deep water between the central and eastern Pacific, constitutes the greatest marine obstacle to the dispersal of shallow-water organisms. However, some species are found on both sides of the EPB. These 'transpacific' species are considered by 'dispersal' biogeographers as evidence of invasions through the barrier. 'Vicariance' biogeographers, on the other hand, think that transpacific species are morphologically conservative remnants of previously continuous distributions. We compared nucleotide sequences in a 642bp region of mitochondrial DNA, and electrophoretically detected alleles in 17 enzymatic loci of central and eastern Pacific populations of Echinothrix diadema, an Indo-Pacific sea urchin recently reported from the eastern Pacific. Both types of molecules produced clear evidence of massive, recent gene flow across the EPB. Thus, rather than being isolated relicts of Tethyan distributions, conspecific populations from the eastern and central Pacific are genetically connected. Though the EPB is biogeographically important as a cause of speciation in many groups, it allows genetic connections in others, possibly through larval transport during El Nino events. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Lessios, HA (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. EM lessiosh@naos.si.edu NR 42 TC 130 Z9 136 U1 1 U2 23 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 APR 7 PY 1998 VL 265 IS 1396 BP 583 EP 588 PG 6 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA ZH079 UT WOS:000073070000006 ER PT J AU Graves, GR AF Graves, GR TI Diagnoses of hybrid hummingbirds (Aves : Trochilidae). 5. Probable hybrid origin of Amazilia distans Wetmore & Phelps SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article ID HELIANGELUS AB Amazilia distans Wetmore & Phelps, 1956, is believed to be a hybrid between Hylocharis cyanus and Amazilia fimbriata. The hybrid, collected in Estado Tachira, Venezuela, exhibits a blended mosaic of plumage characters of the parental species. External measurements of the hybrid fall between the character means of the parental species which overlap in size. 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. NR 21 TC 3 Z9 3 U1 0 U2 3 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 6 PY 1998 VL 111 IS 1 BP 28 EP 34 PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZG953 UT WOS:000073056600003 ER PT J AU Ferrari, FD Benforado, A AF Ferrari, FD Benforado, A TI Setation and setal groups on antenna 1 of Ridgewayia klausruetzleri, Pleuromamma xiphias, and Pseudocalanus elongatus (Crustacea : Copepoda : Calanoida) during the copepodid phase of their development SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Setae added to the antenna 1 of three species of calanoid copepods during copepodid development are allocated to setal groups present on the adult antenna 1. Development of these setal groups is not homogeneous; for a given setal group the copepodid stage at which the first seta appears and at which setal addition is completed varies; whether the setal group is trithek or quadrithek in adult males also varies. These variations suggest several sets of setal groups as candidates for the presumed extra groups added during the adaption of an ancestral calanoid copepod to the pelagic environment. Among these, a set of late developing setal groups is preferred. A model for adding setal groups during copepodid development assumes three source groups are responsible for adding 16 progeny groups. C1 Natl Museum Nat Hist, Dept Invertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. RP Ferrari, FD (reprint author), Natl Museum Nat Hist, Dept Invertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. NR 15 TC 6 Z9 7 U1 1 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 6 PY 1998 VL 111 IS 1 BP 209 EP 221 PG 13 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZG953 UT WOS:000073056600018 ER PT J AU Lu, H Fauchald, K AF Lu, H Fauchald, K TI Description of Eunice weintraubi and E-wui, two new species of eunicid polychaetes from northern Gulf of Mexico SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Eunice weintraubi and Eunice wui are described from shallow waters of the Gulf of Mexico and variability of morphological characters is discussed. Because large numbers of specimens are available, some features of the ontogeny of Eunice wui are also noted. The morphological characters of two related species, Eunice fauchaldi and Eunice multicylindri are compared to each other and to Eunice wui. C1 Natl Museum Nat Hist, Dept Invertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. George Washington Univ, Dept Biol Sci, Washington, DC 20052 USA. RP Lu, H (reprint author), Natl Museum Nat Hist, Dept Invertebrate Zool, Smithsonian Inst, Washington, DC 20560 USA. NR 11 TC 6 Z9 7 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 6 PY 1998 VL 111 IS 1 BP 230 EP 240 PG 11 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZG953 UT WOS:000073056600020 ER PT J AU da Luz, MGE Heller, EJ Cheng, BK AF da Luz, MGE Heller, EJ Cheng, BK TI Exact form of Green functions for segmented potentials SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID ONE-DIMENSIONAL SCATTERING; QUANTUM-MECHANICS; EXACT PROPAGATOR; PATH-INTEGRALS; BOUND-STATES; QUANTIZATION; DIFFRACTION; RESONANCES; AMPLITUDES; BARRIER AB We derive the exact Green functions for segmented potentials, i.e. for potentials of the form V(x) = Sigma(j=1)(N) V((j))(x), where each V((j))(x) has compact support. The expressions depend explicitly on the wavefunctions' quantum amplitudes (e.g. transmission and reflection coefficients) for the individual V((j))'s. We also show that the exact Green functions are in fact generalizations of the usual semiclassical formula. Finally, the possibility of applying the method to a general potential is briefly discussed. C1 Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Fed Parana, Dept Fis, BR-81531970 Curitiba, Parana, Brazil. RP da Luz, MGE (reprint author), Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. EM luz@fisica.ufpr.br NR 45 TC 21 Z9 21 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD APR 3 PY 1998 VL 31 IS 13 BP 2975 EP 2990 PG 16 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA ZH267 UT WOS:000073090000007 ER PT J AU Labandeira, CC AF Labandeira, CC TI How old is the flower and the fly? SO SCIENCE LA English DT Article ID ANGIOSPERMS; POLLINATION; EVOLUTION; ORIGIN C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. Univ Maryland, Dept Entomol, College Pk, MD 20742 USA. RP Labandeira, CC (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. NR 23 TC 41 Z9 42 U1 1 U2 14 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 3 PY 1998 VL 280 IS 5360 BP 57 EP 59 DI 10.1126/science.280.5360.57 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZF314 UT WOS:000072885100032 ER PT J AU Frankham, R Ralls, K AF Frankham, R Ralls, K TI Conservation biology - Inbreeding leads to extinction SO NATURE LA English DT Editorial Material ID GENETICS C1 Macquarie Univ, Sch Biol Sci, Sydney, NSW 2109, Australia. Smithsonian Inst, Natl Zool Pk, Dept Zool Res, Washington, DC 20008 USA. RP Frankham, R (reprint author), Macquarie Univ, Sch Biol Sci, Sydney, NSW 2109, Australia. NR 13 TC 142 Z9 161 U1 6 U2 53 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 2 PY 1998 VL 392 IS 6675 BP 441 EP 442 DI 10.1038/33022 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZF215 UT WOS:000072875200026 ER PT J AU Delehanty, DJ Fleischer, RC Colwell, MA Oring, LW AF Delehanty, DJ Fleischer, RC Colwell, MA Oring, LW TI Sex-role reversal and the absence of extra-pair fertilization in Wilson's phalaropes SO ANIMAL BEHAVIOUR LA English DT Article ID RED-WINGED BLACKBIRDS; SPERM-STORAGE TUBULES; MALE PARENTAL CARE; GENETIC-EVIDENCE; FEMALE CONTROL; TREE SWALLOWS; PATERNITY; BIRDS; BEHAVIOR; CUCKOLDRY AB Extra-pair fertilizations are common in birds, which has led to great interest in how this phenomenon is regulated at a proximate level and how extra-pair fertilizations, and extra-pair fertilization avoidance, shape avian social systems. In Wilson's phalaropes, Phalaropus tricolor, incubation and brood-rearing is performed exclusively by males. Males are able to real only a single brood of four during a breeding season. This suggests that males have a high level of paternity in clutches and broods under their care and, thus, that extra-pair fertilizations;are infrequent. In contrast, female social dominance, lack of territoriality and frequent interactions among breeding adults suggest that both males and females have the opportunity to engage in extra-pair copulations. Using DNA fingerprint band-sharing between putative parents and offspring, we found no evidence of extra-pair fertilizations among 51 offspring from 17 families of phalaropes. Copulation disruption by noncopulatory adults, ability of females to reject copulation attempts and potential fitness benefits to females by avoiding extra-pair fertilizations were sufficient to explain the absence of extra-pair fertilizations in Wilson's phalaropes. We propose that sex-role reversal affects the relative costs and benefits to females of seeking extra-pair fertilizations. At the time of clutch completion, females have invested particularly heavily in their clutches due to intense competition among females to gain and keep a mate during the pre-laying and laying periods. After clutch completion, nest success requires significant male parental care. Benefits to females in gaining extra-pair fertilizations may be offset by the risk of losing male parental care. (C) 1998 The Association for the Study of Animal Behaviour. C1 Univ N Dakota, Dept Biol, Grand Forks, ND 58202 USA. Smithsonian Inst, Natl Zool Pk, Washington, DC 20560 USA. RP Delehanty, DJ (reprint author), Univ Nevada, Dept Biol BRRL314, Reno, NV 89557 USA. EM djdele@scs.unr.edu NR 57 TC 29 Z9 29 U1 3 U2 25 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0003-3472 J9 ANIM BEHAV JI Anim. Behav. PD APR PY 1998 VL 55 BP 995 EP 1002 DI 10.1006/anbe.1997.0670 PN 4 PG 8 WC Behavioral Sciences; Zoology SC Behavioral Sciences; Zoology GA ZM376 UT WOS:000073532300019 ER PT J AU Forman, P AF Forman, P TI Molecular beam measurements of nuclear moments before magnetic resonance. Part I: I.I. Rabi and deflecting magnets to 1938 SO ANNALS OF SCIENCE LA English DT Review ID PHYSICAL RESEARCH AB Investigation of the origin and function of three magnets from I. I. Rabi's laboratory at Columbia University leads to a closer inquiry into the early history of molecular beam evaluations of the angular momenta and magnetic moments of atomic nuclei than has been undertaken heretofore. The resulting insights into the background and the course of Rabi's research programme would probably not have occurred without the orientation enforced by these artifacts. C1 Smithsonian Inst, Washington, DC 20560 USA. RP Forman, P (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 204 TC 2 Z9 2 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0003-3790 J9 ANN SCI JI Ann. Sci. PD APR PY 1998 VL 55 IS 2 BP 111 EP 160 DI 10.1080/00033799800200141 PG 50 WC History & Philosophy Of Science SC History & Philosophy of Science GA ZL436 UT WOS:000073432700001 ER PT J AU Soufli, R Gullikson, EM AF Soufli, R Gullikson, EM TI Absolute photoabsorption measurements of molybdenum in the range 60-930 eV for optical constant determination SO APPLIED OPTICS LA English DT Article ID MO; TA; AG; AU AB Transmission measurements for the optical constants delta, beta of the complex refractive index n = 1 - delta + i beta of molybdenum are performed in the energy range 60-930 eV. Free-standing C/Mo/C foils of five different thicknesses are used, and the results are normalized for the presence of the carbon layers in the samples. These absorption results are combined with previous experimental data in the lower energy range and values from the atomic tables to obtain the imaginary (absorptive) part of the refractive index for molybdenum in the range 1-30,000 eV. The real (dispersive) part of n was calculated from Kramers-Kronig analysis with the above absorption data. An evaluation with the partial sum rules demonstrates that this new compilation provides an improved set of values for n, covering a wider energy range compared with the current tabulated values. The new results are applied sc as to calculate the normal-incidence reflectivities of Mo/Si and Mo/Be multilayer mirrors. (C) 1998 Optical Society of America. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. RP Soufli, R (reprint author), Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. NR 14 TC 34 Z9 34 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 1 PY 1998 VL 37 IS 10 BP 1713 EP 1719 DI 10.1364/AO.37.001713 PG 7 WC Optics SC Optics GA ZD695 UT WOS:000072713700001 PM 18273078 ER PT J AU Shen, ZQ Wan, TS Moran, JM Jauncey, DL Reynolds, JE Tzioumis, AK Gough, RG Ferris, RH Sinclair, MW Jiang, DR Hong, XY Liang, SG Edwards, PG Costa, ME Tingay, SJ McCulloch, PM Lovell, JEJ King, EA Nicolson, GD Murphy, DW Meier, DL van Ommen, TD White, GL AF Shen, ZQ Wan, TS Moran, JM Jauncey, DL Reynolds, JE Tzioumis, AK Gough, RG Ferris, RH Sinclair, MW Jiang, DR Hong, XY Liang, SG Edwards, PG Costa, ME Tingay, SJ McCulloch, PM Lovell, JEJ King, EA Nicolson, GD Murphy, DW Meier, DL van Ommen, TD White, GL TI A 5 GHz Southern Hemisphere VLBI survey of compact radio sources. II. SO ASTRONOMICAL JOURNAL LA English DT Review DE BL Lacertae objects, general; radio continuum; surveys ID BL-LACERTAE OBJECTS; ACTIVE GALACTIC NUCLEI; BLAZAR PKS 0537-441; GAMMA-RAY EMISSION; MILLIMETER CONTINUUM MEASUREMENTS; FREQUENCY VARIABLE SOURCES; COMPLETE SAMPLE; X-RAY; OPTICAL POLARIZATION; MULTIFREQUENCY OBSERVATIONS AB We report the results of a 5 GHz Southern Hemisphere snapshot VLBI observation of a sample of blazars. The observations were performed with the Southern Hemisphere VLBI Network plus the Shanghai station in 1993 May. Twenty-three hat-spectrum, radio-loud sources were imaged. These are the first VLBI images for 15 of the sources. Eight of the sources are EGRET (>100 MeV) gamma-ray sources. The milliarcsecond morphology shows a core-jet structure for 12 sources and a single compact core for the remaining 11. No compact doubles were seen. Compared with other radio images at different epochs and/or different frequencies, three core-jet blazars show evidence of bent jets, and there is some evidence for superluminal motion in the cases of two blazars. Detailed descriptions for individual blazars are given. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Shanghai Astron Observ, Shanghai 200030, Peoples R China. Australia Telescope Natl Facil, Epping, NSW 2121, Australia. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Univ Western Australia, Dept Phys, Nedlands, WA 6009, Australia. Mt Stromlo & Siding Spring Observ, Weston Creek, ACT 2611, Australia. Univ Tasmania, Dept Phys, Hobart, Tas 7001, Australia. Hartebeesthoek Radio Astron Observ, ZA-1740 Krugersdorp, South Africa. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Western Sydney Nepean, Dept Phys, Kingswood, NSW 2747, Australia. RP Shen, ZQ (reprint author), Acad Sinica, Inst Astron & Astrophys, POB 1-87, Taipei 115, Taiwan. RI Tingay, Steven/B-5271-2013; van Ommen, Tas/B-5020-2012; King, Edward/A-1473-2012 OI van Ommen, Tas/0000-0002-2463-1718; King, Edward/0000-0002-6898-2130 NR 137 TC 34 Z9 34 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1998 VL 115 IS 4 BP 1357 EP 1370 DI 10.1086/300284 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG635 UT WOS:000073023500010 ER PT J AU McLeod, BA Bernstein, GM Rieke, MJ Weedman, DW AF McLeod, BA Bernstein, GM Rieke, MJ Weedman, DW TI The gravitational lens MG 0414+0534: A link between red galaxies and dust SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies, evolution; gravitational lensing ID ELLIPTICAL GALAXIES; RADIO GALAXIES; TELESCOPE AB We present near-IR observations of the red gravitational lens system MG 0414 + 0534. Our images are of sufficient quality to allow photometry of all four QSO images and the lens galaxy. The observations show that the K-band brightnesses of the components are more similar to the radio brightnesses than to the optical and thus support the notion that the system is highly reddened. The differing brightnesses at visible wavelengths are interpreted as variable amounts of extinction in the lens galaxy. The lens galaxy is detected in the K band and is as red as any other known galaxy of comparable apparent magnitude. An estimate of the redshift of the lens galaxy of 0.45 < z < 0.6 is determined from the Faber-Jackson relation and photometric considerations. By extension, we argue that other very red field galaxies may contain large amounts of dust. K-band spectra of the individual components show no difference in the H alpha equivalent widths among the components. This is evidence against significant microlensing. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP McLeod, BA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 19 TC 32 Z9 32 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1998 VL 115 IS 4 BP 1377 EP 1382 DI 10.1086/300285 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG635 UT WOS:000073023500012 ER PT J AU Caldwell, N Rose, JA AF Caldwell, N Rose, JA TI Low-luminosity early-type galaxies in the Coma Cluster: Variations in spectral properties SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies, clusters, individual (Coma); galaxies, dwarf; galaxies, evolution; galaxies, fundamental parameters; galaxies, stellar content ID STELLAR POPULATIONS; ELLIPTIC GALAXIES; CATALOG; STARBURSTS; FIELD AB We present spectra of nine low-luminosity early-type galaxies (M-B > -17.5) in the Coma Cluster. The spectra, which were obtained with the Multiple Mirror Telescope and cover the spectral region 3300-5350 Angstrom exhibit a large variation in Balmer line strengths. In fact, the line-strength variation among the Coma low-luminosity galaxies is as large as that found among a sample of low-luminosity elliptical galaxies in the Virgo Cluster and lower density environments. When compared with detailed population synthesis models, the variation in Balmer line strengths among the Coma galaxies indicates a range in luminosity-weighted mean age from similar to 1 to similar to 12 Gyr. The two youngest galaxies are shown to be in a poststarburst state, i.e., they are not simply former spirals whose star formation was recently terminated. Moreover, the similar to 1 Gyr ages of these two youngest low-luminosity galaxies are similar to those of the brighter poststarburst galaxies in the Coma Cluster. C1 Harvard Smithsonian Ctr Astrophys, FL Whipple Observ, Amado, AZ 85645 USA. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. RP Caldwell, N (reprint author), Harvard Smithsonian Ctr Astrophys, FL Whipple Observ, POB 97, Amado, AZ 85645 USA. NR 27 TC 21 Z9 21 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1998 VL 115 IS 4 BP 1423 EP 1432 DI 10.1086/300295 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG635 UT WOS:000073023500018 ER PT J AU Gomez, M Lada, CJ AF Gomez, M Lada, CJ TI From Head to Sword: The clustering properties of stars in Orion SO ASTRONOMICAL JOURNAL LA English DT Article DE open clusters and associations, individual (Orion A, lambda Orionis) ID MOLECULAR CLOUD; LUMINOSITY FUNCTIONS; TRAPEZIUM CLUSTER; OBJECTS; TAURUS; REGION; NEBULA; IMAGES; MULTIPLICITY; MONOCEROS AB We investigate the structure in the spatial distributions of optically selected samples of young stars in the Head (lambda Orionis) and in the Sword (Orion A) regions of the constellation of Orion with the aid of stellar surface density maps and the two-point angular correlation function. The distributions of young stars in both regions are found to be nonrandom and highly clustered. Stellar surface density maps reveal three distinct clusters in the lambda Ori region. The two-point correlation function displays significant features at angular scales that correspond to the radii and separations of the three clusters identified in the surface density maps. Most young stars in the lambda Ori region (similar to 80%) are presently found within these three clusters, consistent with the idea that the majority of young stars in this region were formed in dense protostellar clusters that have significantly expanded since their formation. Over a scale of similar to 0.degrees 05-0.degrees 5 the correlation function is well described by a single power law that increases smoothly with decreasing angular scale. This suggests that, within the clusters, the stars either are themselves hierarchically clustered or have a volume density distribution that falls steeply with radius. The relative lack of Ha emission-line stars in the one cluster in this region that contains OB stars suggests a timescale for emission-line activity of less than 4 Myr around late-type stars in the cluster and may indicate that the lifetimes of protoplanetary disks around young stellar objects are reduced in clusters containing O stars. The spatial distribution of young stars in the Orion A region is considerably more complex. The angular correlation function of the OB stars (which are mostly foreground to the Orion A molecular cloud) is very similar to that of the Hot stars (which are located mostly within the molecular cloud) and significantly different from that of the young stars in the lambda Ori region. This suggests that, although spatially separated, both populations in the Orion A region may have originated from a similar fragmentation process. Stellar surface density maps and modeling of the angular correlation function suggest that somewhat less than half of the OB and H alpha stars in the Orion A cloud are presently within well-defined stellar clusters. Although all the OB stars could have originated in rich clusters, a significant fraction of the H alpha stars appear to have formed outside such clusters in a more spatially dispersed manner. The close similarity of the angular correlation functions of the OB and H alpha stars toward the molecular cloud, in conjunction with the earlier indications of a relatively high star formation rate and high gas pressure in this cloud, is consistent with the idea that older, foreground OB stars triggered the current episode of star formation in the Orion A cloud. One of the OB clusters (Upper Sword) that is foreground to the cloud does not appear to be associated with any of the clusterings of emission-line stars, again suggesting a timescale (<4 Myr) for emission-line activity and disk lifetimes around late-type stars born in OB clusters. C1 Univ Nacl Cordoba, Astron Observ, RA-5000 Cordoba, Argentina. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Gomez, M (reprint author), Univ Nacl Cordoba, Astron Observ, Laprida 854, RA-5000 Cordoba, Argentina. EM mercedes@oac.uncor.edu; clada@cfa.harvard.edu NR 41 TC 29 Z9 29 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1998 VL 115 IS 4 BP 1524 EP 1535 DI 10.1086/300276 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG635 UT WOS:000073023500028 ER PT J AU Dobrzycka, D Dobrzycki, A Engels, D Hagen, HJ AF Dobrzycka, D Dobrzycki, A Engels, D Hagen, HJ TI HS 0551+7241: A new possible magnetic cataclysmic variable in the Hamburg-CfA Bright Quasar Survey SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries, close; novae, cataclysmic variables; stars, individual (HS 0551 + 7241) ID INTERMEDIATE POLARS; FO-AQUARII; SPECTROSCOPY; STARS; HERCULIS; DQ; VARIABILITY AB We present an analysis of spectroscopic observations of a newly discovered cataclysmic variable, HS 0551+7241. In 1995, the star's brightness dropped by Delta B similar to 2.5 mag and HS 0551+7241 entered a low state lasting for similar to 2 yr. The H alpha, H beta, and He Ir lambda 4686 emission-line radial velocity curves show evidence of short similar to 50 minute fluctuations superposed on longer, similar to 4 hr, variations. We find similar modulations in the line fluxes and the line equivalent widths. The continuum magnitude light curves suggest that HS 0551+7241 may be an eclipsing system. If the 4 hour period is related to the orbital period, then the mass function is similar to 0.138 M.. Relatively strong He II lambda 4686 emission and short fluctuations may suggest that the binary is an intermediate polar. In that case, the similar to 50 minute variations would correspond to an Alfven radius of similar to 3 x 10(10) cm. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Hamburg, D-21029 Hamburg, Germany. RP Dobrzycka, D (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 31 TC 3 Z9 3 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1998 VL 115 IS 4 BP 1634 EP 1639 DI 10.1086/300281 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG635 UT WOS:000073023500037 ER PT J AU Pietz, J Kerp, J Kalberla, PMW Burton, WB Hartmann, D Mebold, U AF Pietz, J Kerp, J Kalberla, PMW Burton, WB Hartmann, D Mebold, U TI The Galactic X-ray halo SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxy : halo; galaxy : kinematics and dynamics; X-rays : ISM ID HIGH-VELOCITY CLOUDS; DEEP ROSAT SURVEY; H-I; HYDROSTATIC EQUILIBRIUM; INTERSTELLAR-MEDIUM; MASS DENSITY; COMPLEX-M; DIFFUSE; GALAXY; DISTANCE AB We analyzed the intensity distribution of the 3/4 keV and 1/4 keV diffuse soft X-ray background by correlating the ROSAT all-sky survey with the Leiden/Dwingeloo H I survey. We found that the 3/4 keV and 1/4 keV intensity distributions can be modelled by a contribution from an isothermal (kT = 0.135 keV) flattened X-ray halo superposed on the radiation from an extragalactic X-ray background. The exponential scale height of the X-ray halo is about 4.4 kpc and its radial scale length is about 15 kpc; the X-ray halo luminosity, L-X, is about 7.10(39) erg s(-1). C1 Univ Bonn, Inst Radioastron, D-53121 Bonn, Germany. Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kalberla, PMW (reprint author), Univ Bonn, Inst Radioastron, Hugel 71, D-53121 Bonn, Germany. NR 61 TC 57 Z9 57 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 1 PY 1998 VL 332 IS 1 BP 55 EP 70 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZH501 UT WOS:000073117400013 ER PT J AU Boulanger, F Bronfman, L Dame, TM Thaddeus, P AF Boulanger, F Bronfman, L Dame, TM Thaddeus, P TI CO and IRAS observations of the chamaeleon molecular clouds SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : dust, clouds; infrared : ISM : continuum; ISM : Chamaeleon clouds; radio lines : ISM ID CHAMELEON DARK CLOUDS; INTERSTELLAR CLOUDS; MILKY-WAY; STELLAR POPULATION; CIRRUS CLOUDS; H-I; EMISSION; DUST; EXTINCTION; GAS AB We present an extensive survey of the CO emission from the conspicuous complex of dark nebulae in Chamaeleon. The CO observations together with IRAS, extinction and H I data are used to study the distribution of interstellar matter in the complex. The comparison of the cloud 100 mu m emission with Av shows that the far-infrared brightness traces the gas over most of the surface of the complex, specifically where Av < 2mag and outside a small number of regions heated by embedded stars. For the complex as a whole and for its largest clouds, masses computed from the far infrared emission roughly agree with those derived from the CO surveys using the standard Galactic value of the CO-to-H-2 conversion factor. However, among the smaller clouds the H-2 masses computed from CO emission are lower than those derived from the 100 mu m data by as much as a factor of 10. The molecular emission is observed to be primarily associated with the 100 mu m emission characterized by cold IRAS colors: low 60/100 mu m flux ratio and no 12 and 25 mu m emission while the 100 mu m emission with warm IRAS colors is poorly traced by CO emission. The observed correlation between the spectral distribution of the dust emission with the molecular emission may be related to the effect of the far-UV extinction of dust on the formation of CO. In some regions it is clear that the warm infrared component cannot be accounted for by matter detected in the CO and H I surveys; we suggest that these regions contain molecular gas without detected CO emission. C1 Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Univ Chile, Dept Astron, Santiago, Chile. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Boulanger, F (reprint author), Univ Paris 11, Inst Astrophys Spatiale, Batiment 121, F-91405 Orsay, France. RI Bronfman, Leonardo/H-9544-2013 OI Bronfman, Leonardo/0000-0002-9574-8454 NR 66 TC 62 Z9 62 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 APR 1 PY 1998 VL 332 IS 1 BP 273 EP 290 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZH501 UT WOS:000073117400037 ER PT J AU Hill, RJ Ferrarese, L Stetson, PB Saha, A Freedman, WL Graham, JA Hoessel, JG Han, MS Huchra, J Hughes, SM Illingworth, GD Kelson, D Kennicutt, RC Bresolin, F Harding, P Turner, A Madore, BF Sakai, S Silbermann, NA Mould, JR Phelps, R AF Hill, RJ Ferrarese, L Stetson, PB Saha, A Freedman, WL Graham, JA Hoessel, JG Han, MS Huchra, J Hughes, SM Illingworth, GD Kelson, D Kennicutt, RC Bresolin, F Harding, P Turner, A Madore, BF Sakai, S Silbermann, NA Mould, JR Phelps, R TI The extragalactic distance scale key project. V. Photometry of the brightest stars in M100 and the calibration of WFPC2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; distance scale; galaxies, individual (M100); galaxies, photometry; techniques, photometric ID HUBBLE-SPACE-TELESCOPE; PERFORMANCE; CEPHEIDS; CONSTANT AB We present multiepoch VI observations of the brightest stars in the Virgo spiral galaxy M100 obtained with the WFPC2 aboard the Hubble Space Telescope. Particular attention has been given to the WFPC2 calibration process, and a new calibration is presented hem We find that a calibration based on short exposure (t less than or equal to 60 sec) observations of the galactic globular clusters omega Cen, Pal 4, and NGC 2419 yields results that are in excellent agreement with the calibration of Holtzmann et al. However, a calibration based on longer exposures (t greater than or equal to 1300 s) yields magnitudes that are systematically brighter by 0.05 mag, on average, in both V and I. We have independently employed both the DAOPHOT/ALLFRAME and DoPHOT photometry routines in reducing the M100 data and have found that the two packages yield magnitudes that agree to better than 0.05 mag except for the WFPC2 chip 3 and WFPC2 chip 4 I data. Severe crowding appears to be the problem in the case of the WFPC2 chip 3 data, but we have been unable to determine the source of the discrepancy for the WFPC2 chip 4 I data. We consider the better than 0.05 mag agreement for the other chip/filter combinations to be quite good under the circumstances prevailing in this data set: an undersampled point-spread function (PSF), faint stars, a rapidly varying background, and moderate to severe crowding. A color-magnitude diagram for the brightest stars in M100 is also presented, which shows a plume of bright blue supergiants extending to at least V similar to 23 mag, or M-V similar to 8 mag. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Royal Greenwich Observ, Cambridge CB3 0EZ, England. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. RP Hill, RJ (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. EM hill@esa.nascom.nasa.gov; lff@astro.caltech.edu; stetson@dao.nrc.ca; saha@stsci.edu; wendy@ociw.edu; graham@jag.ciw.edu; hoessel@uwfpc.astro.wisc.edu; han@adcode.astro.wisc.edu; huchra@cfa.harvard.edu; hughes@mail.ast.cam.ac.uk; gdi@lick.ucolick.org; kelson@lick.ucolick.org; robk@as.arizona.edu; fbresolin@as.arizona.edu; pharding@as.arizona.edu; aturner@as.arizona.edu; barry@ipac.caltech.edu; shoko@ipac.caltech.edu; nancys@ipac.caltech.edu; jrm@merlin.anu.edu.au; phelps@ociw.edu NR 21 TC 52 Z9 52 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1998 VL 496 IS 2 BP 648 EP 660 DI 10.1086/305389 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG868 UT WOS:000073048100007 ER PT J AU Wargelin, BJ Beiersdorfer, P Liedahl, DA Kahn, SM von Goeler, S AF Wargelin, BJ Beiersdorfer, P Liedahl, DA Kahn, SM von Goeler, S TI Observation and modeling of high-n iron L-shell lines from intermediate ion stages SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; line, identification; sun, X-rays, gamma rays; X-rays, general ID X-RAY-SPECTRUM; PLASMAS; FLARES; ATOMS AB The spectra of highly ionized iron species between 7 and 9 Angstrom have been studied using data obtained at the Princeton Large Torus tokamak under plasma conditions similar to those present in solar and stellar flares. The wavelengths of many iron lines are measured with very high accuracy (lambda/Delta lambda up to 4 x 10(4)), along with several other lines in species such as He-like Al XII and Mg XI. Theoretical spectra that predict both the wavelength and the intensity of Fe emission lines are compared with the observed spectra and are used to make accurate line identifications. Virtually all the observed iron lines are found to arise from n = 4, 5, and 6 --> 2 transitions in Fe XXI-XXIV, and many lines are identified for the first time. Several transitions are shown to have diagnostic applications, and a detailed analysis of the density sensitivity of Fe XXII lines is presented. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Wargelin, BJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 27 TC 30 Z9 31 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1998 VL 496 IS 2 BP 1031 EP 1043 DI 10.1086/305410 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG868 UT WOS:000073048100039 ER PT J AU Yan, M Sadeghpour, HR Dalgarno, A AF Yan, M Sadeghpour, HR Dalgarno, A TI Photoionization cross sections of He and H-2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; molecular data; molecular processes; ultraviolet, general; X-rays, general ID HIGH-ENERGY PHOTON; MULTICHANNEL CONTINUUM STATES; TO-SINGLE PHOTOIONIZATION; DOUBLE-IONIZATION; DISSOCIATIVE PHOTOIONIZATION; COMPTON-SCATTERING; MOLECULAR-HYDROGEN; SYNCHROTRON-RADIATION; HIGH-RESOLUTION; SPLINE BASIS AB We combine accurate measurements at low energies and theoretical calculations at high energies to construct sets of photoionization cross sections of He and H-2 that should be reliable at all energies. We control the accuracy of the recommended cross section data by ensuring that they satisfy a range of oscillator strength sum rules. We provide accurate analytic formulae for the photoionization cross sections that have the proper asymptotic form. At high frequencies the cross sections for H-2 are 2.8 times those for H. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Yan, M (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 91 TC 160 Z9 162 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1998 VL 496 IS 2 BP 1044 EP 1050 DI 10.1086/305420 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG868 UT WOS:000073048100040 ER PT J AU Myers, PC AF Myers, PC TI Cluster-forming molecular cloud cores SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, clouds; stars, formation; turbulence ID AMBIPOLAR DIFFUSION; STAR FORMATION; DENSE CORES; DARK CLOUDS; AMMONIA; MASSES AB We model a turbulent cloud core ionized by cosmic rays, having Bonnor-Ebert condensations that are both critically stable and cut off from MHD waves in the core. We take these condensations to be the precursors of stars in clusters. The model predicts that such condensations can exist in 'massive" cores having a FWHM line width greater than 0.9 km s(-1) and a column density greater than 1 x 10(22) cm(-2), as is observed in cluster-forming cores in Perseus, Orion, and Cepheus, but cannot exist in the less turbulent, less opaque "low-mass" cores in Taurus, which have no associated clusters. In cluster-forming cores, these condensations are predicted to have mass similar to 1 M(.) and radius similar to 0.03 pc, consistent with the mass and spacing of most young stars in clusters. Such critically stable, cutoff condensations may be identified by their small size and narrow spectral lines, if observed with sufficient sensitivity, spectral resolution, and angular resolution. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Myers, PC (reprint author), Harvard Smithsonian Ctr Astrophys, Mail Stop 42,60 Garden St, Cambridge, MA 02138 USA. EM pmyers@cfa.harvard.edu NR 42 TC 64 Z9 64 U1 0 U2 0 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 1 PY 1998 VL 496 IS 2 BP L109 EP L112 DI 10.1086/311256 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZG873 UT WOS:000073048600013 ER PT J AU Dietrich, M Peterson, BM Albrecht, P Altmann, M Barth, AJ Bennie, PJ Bertram, R Bochkarev, NG Bock, H Braun, JM Burenkov, A Collier, S Fang, LZ Francis, OP Filippenko, AV Foltz, CB Gassler, W Gaskell, CM Geffert, M Ghosh, KK Hilditch, RW Honeycutt, RK Horne, K Huchra, JP Kaspi, S Kummel, M Leighly, KM Leonard, DC Malkov, YF Mikhailov, V Miller, HR Morrill, AC Noble, J O'Brien, PT Oswalt, TD Pebley, SP Pfeiffer, M Pronik, VI Qian, BC Robertson, JW Robinson, A Rumstay, KS Schmoll, J Sergeev, SG Sergeeva, EA Shapovalova, AI Skillman, DR Snedden, SA Soundararajaperumal, S Stirpe, GM Tao, J Turner, GW Wagner, RM Wagner, SJ Wei, JY Wu, H Zheng, W Zou, ZL AF Dietrich, M Peterson, BM Albrecht, P Altmann, M Barth, AJ Bennie, PJ Bertram, R Bochkarev, NG Bock, H Braun, JM Burenkov, A Collier, S Fang, LZ Francis, OP Filippenko, AV Foltz, CB Gassler, W Gaskell, CM Geffert, M Ghosh, KK Hilditch, RW Honeycutt, RK Horne, K Huchra, JP Kaspi, S Kummel, M Leighly, KM Leonard, DC Malkov, YF Mikhailov, V Miller, HR Morrill, AC Noble, J O'Brien, PT Oswalt, TD Pebley, SP Pfeiffer, M Pronik, VI Qian, BC Robertson, JW Robinson, A Rumstay, KS Schmoll, J Sergeev, SG Sergeeva, EA Shapovalova, AI Skillman, DR Snedden, SA Soundararajaperumal, S Stirpe, GM Tao, J Turner, GW Wagner, RM Wagner, SJ Wei, JY Wu, H Zheng, W Zou, ZL TI Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. XII. Ground-based monitoring of 3C 390.3 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies, active; galaxies, individual (3C 390.3); galaxies, Seyfert ID SHORT-TIMESCALE VARIABILITY; MULTIWAVELENGTH OBSERVATIONS; EMISSION-LINES; RADIO GALAXIES; FE-II; 3C-390.3; CONTINUUM; NGC-5548; NGC-4151; NGC-3783 AB Results of a ground-based optical monitoring campaign on 3C 390.3 in 1994-1995 are presented. The broadband fluxes (B, V, R, and I), the spectrophotometric optical continuum flux F-lambda(5177 Angstrom), and the integrated emission-line fluxes of H alpha, H beta, H gamma, He I lambda 5876, and He II lambda 4686 all show a nearly monotonic increase with episodes of milder short-term variations superposed. The amplitude of the continuum variations increases with decreasing wavelength (4400-9000 Angstrom). The optical continuum variations follow the variations in the ultraviolet and X-ray with time delays, measured from the centroids of the crosscorrelation functions, typically around 5 days, but with uncertainties also typically around 5 days; zero time delay between the high-energy and low-energy continuum variations cannot be ruled out. The strong optical emission lines H alpha, H beta, H gamma, and He I lambda 5876 respond to the high-energy continuum variations with time delays typically about 20 days, with uncertainties of about 8 days. There is some evidence that He II lambda 4686 responds somewhat more rapidly, with a time delay of around 10 days, but again, the uncertainties are quite large (similar to 8 days). The mean and rms spectra of the H alpha and H beta line profiles provide indications for the existence of at least three distinct components located at +/-4000 and 0 km s(-1) relative to the line peak. The emission-line profile variations are largest near line center. C1 Landessternwarte Heidelberg, D-69117 Heidelberg, Germany. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Univ Sternwarte Gottingen, D-37083 Gottingen, Germany. Univ Sternwarte, D-53121 Bonn, Germany. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Lowell Observ, Flagstaff, AZ 86001 USA. Univ Prospect, Sternberg Astron Inst, Moscow 119899, Russia. Russian Acad Sci, Special Astrophys Observ, Nizhnii Arkhyz 357147, Karachaj Cherke, Russia. Univ Arizona, MMT Observ, Tucson, AZ 85721 USA. Univ Sternwarte, D-81679 Munich, Germany. Vainu Bappu Observ, Indian Inst Astrophys, Alangayam 635701, TN, India. Indiana Univ, Dept Astron, Bloomington, IN 47405 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Tel Aviv Univ, Dept Phys & Astron, IL-69978 Tel Aviv, Israel. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Crimean Astrophys Observ, UA-334413 Nauchnyi, Crimea, Ukraine. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Western Kentucky Univ, Dept Phys & Astron, Ctr Automated Space Sci, Bowling Green, KY 42101 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Florida Inst Technol, Dept Phys & Space Sci, Melbourne, FL 32901 USA. Chinese Acad Sci, Shanghai Observ, Shanghai 200030, Peoples R China. Univ Hertfordshire, Dept Phys Sci, Div Phys & Astron, Hatfield AL10 9AB, Herts, England. Valdosta State Univ, Dept Phys Astron & Geol, Valdosta, GA 31698 USA. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. Ctr Basement Astrophys, Laurel, MD 20723 USA. Osservatorio Astron Bologna, I-40126 Bologna, Italy. Beijing Astron Observ, Beijing 100080, Peoples R China. Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. RP Dietrich, M (reprint author), Landessternwarte Heidelberg, D-69117 Heidelberg, Germany. RI Skillman, David/C-8995-2013; Stirpe, Giovanna/O-9393-2015; OI Stirpe, Giovanna/0000-0002-3702-8731; Gaskell, C/0000-0003-4888-2009 NR 55 TC 90 Z9 91 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 1998 VL 115 IS 2 BP 185 EP 202 DI 10.1086/313085 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZF237 UT WOS:000072877400003 ER PT J AU Wolniewicz, L Simbotin, I Dalgarno, A AF Wolniewicz, L Simbotin, I Dalgarno, A TI Quadrupole transition probabilities for the excited rovibrational states of H-2 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE line, identification; molecular processes ID MOLECULAR-HYDROGEN; INFRARED RESPONSE; PHOTODISSOCIATION REGIONS; ULTRAVIOLET-RADIATION; INTERSTELLAR H2; ORION NEBULA; GROUND-STATE; EMISSION; ENERGIES; GAS AB Accurate calculations of the quadrupole moment of H-2, carried out with a 494 term variational representation of the electronic eigenfunction, are reported, and the quadrupole transition probabilities connecting all the bound rovibrational levels of H-2 are presented. C1 Nicholas Copernicus Univ, Inst Phys, PL-87100 Torun, Poland. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Wolniewicz, L (reprint author), Nicholas Copernicus Univ, Inst Phys, Grudziadska 5, PL-87100 Torun, Poland. RI Wolniewicz, Lutoslaw/R-1808-2016 NR 32 TC 132 Z9 132 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 1998 VL 115 IS 2 BP 293 EP 313 DI 10.1086/313091 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZF237 UT WOS:000072877400010 ER PT J AU Eberhard, JR AF Eberhard, JR TI Evolution of nest-building behavior in Agapornis parrots SO AUK LA English DT Article ID MITOCHONDRIAL-DNA; TREE TOPOLOGIES; AMPLIFICATION AB Five species in the African lovebird genus Agapornis are the only parrots, other than Monk Parakeets (Myiopsitta monachus), that construct nests. Four species (A. personata, A. fischeri, A. lilianae, and A. nigrigenis) build domed nests within cavities, and a fifth (A. roseicollis) builds a cup-shaped nest within a cavity. The other members of the genus have nesting behavior that is more typical of other parrots: A. cana and A. taranta nest in cavities that are lined with nesting material, and A. pullaria excavates burrows in arboreal ant or termite nests. To reconstruct the evolution of nest-building behavior in Agapornis, I sequenced a 622-bp portion of the cytochrome-b gene (mtDNA) and used the sequence data to build a phylogenetic tree. The phylogeny shows that the divergence between the nest-building species and cana, taranta, and pullaria occurred early in the evolution of the genus. The nest builders form a monophyletic clade, and the small amount of sequence divergence between personata, fischeri, lilianae, and nigrigenis indicates that they probably should be considered subspecies of a single species. A reconstruction of the evolution of nest-building behavior on the phylogeny indicates that the construction of a domed nest is derived from the habit of lining the nest, because the nesting material is used to build progressively more complex nest structures. Within Agapornis, nest building is associated with colonial breeding. The construction of a nest within a cavity may allow breeding pairs to modify and use cavities that otherwise might be unsuitable. This would, in turn, give pairs added flexibility in nest-site choice, thereby facilitating colonial breeding. C1 Princeton Univ, Dept Ecol & Evolut Biol, Princeton, NJ 08544 USA. RP Eberhard, JR (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 28 TC 23 Z9 27 U1 2 U2 15 PU AMER ORNITHOLOGISTS UNION PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0004-8038 J9 AUK JI AUK PD APR PY 1998 VL 115 IS 2 BP 455 EP 464 PG 10 WC Ornithology SC Zoology GA ZH635 UT WOS:000073131400018 ER PT J AU Smeds, SA Uher, P Cerny, P Wise, MA Gustafsson, L Penner, P AF Smeds, SA Uher, P Cerny, P Wise, MA Gustafsson, L Penner, P TI Graftonite-beusite in Sweden: Primary phases, products of exsolution, and distribution in zoned populations of granitic pegmatites SO CANADIAN MINERALOGIST LA English DT Article DE graftonite; beusite; triphylite; sarcopside; phosphates; exsolution; granitic pegmatite; regional zoning; Sweden ID NORTHWEST-TERRITORIES; CRYSTAL-STRUCTURE; FIELD; GEOCHEMISTRY; PETROLOGY; FELDSPAR; AGES AB Graftonite - beusite is relatively widespread in the LCT family of granitic pegmatites of the Bothnian basin and of the Uto - Mysingen field in Sweden. It commonly constitutes the matrix containing either coarse lamellae of sarcopside, which in turn hosts fine lamellae of triphylite, or abundant lamellae of triphylite with bimodal size-distribution. Deformed and recrystallized granular aggregates of graftonite with triphylite, wolfeite and sarcopside are rare. Graftonite - beusite is systematically Ca,Mn-rich and Mg-poor relative to sarcopside, which in rum is slightly Mn-rich and distinctly Mg-poor relative to the Li-concentrating triphylite. Bulk compositions of the lamellar aggregates, crystal-chemical and textural relationships among the individual phosphates, and cation distribution-coefficients indicate two patterns of exsolution that generated the lamellar intergrowths from disordered homogeneous precursors: Ca,Li-poor graftonite exsolved lithian sarcopside, which in turn broke down to sarcopside with triphylite lamellae, and Ca,Li(Mn)-rich graftonite - beusite exsolved triphylite directly. In regional zoning of pegmatite groups, Ca-bearing graftonite - beusite is either the first Fe,Mn(Li)-phosphate encountered in the beryl - columbite pegmatites, or it is found within the zone of beryl - columbite - triphylite pegmatites. Appreciable concentrations of Ca, Fe, Mn (and in part Mg), but low levels of F and Na, are required to stabilize graftonite - beusite. Good correlation of the Mn/(Mn + Fe) values of the phosphates with those of garnet suggests that the homogeneous graftonite beusite precursor could have been generated by phosphorus-induced destabilization of garnet. C1 Uppsala Univ, Inst Earth Sci, SE-75236 Uppsala, Sweden. Univ Manitoba, Dept Geol Sci, Winnipeg, MB R3T 2N2, Canada. Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. RP Smeds, SA (reprint author), Uppsala Univ, Inst Earth Sci, Villavagen 16, SE-75236 Uppsala, Sweden. NR 48 TC 22 Z9 22 U1 1 U2 2 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD APR PY 1998 VL 36 BP 377 EP 394 PN 2 PG 18 WC Mineralogy SC Mineralogy GA 112YT UT WOS:000075525000011 ER PT J AU Cerny, P Ercit, TS Wise, MA Chapman, R Buck, HM AF Cerny, P Ercit, TS Wise, MA Chapman, R Buck, HM TI Compositional, structural and phase relationships in titanian ixiolite and titanian columbite tantalite SO CANADIAN MINERALOGIST LA English DT Article DE titanium; columbite; tantalite; ixiolite; order-disorder; exsolution ID WODGINITE GROUP; NB-BEARING; TA-BEARING; MINERALS; PEGMATITES; GRANITE; TRENDS AB Titanium-enriched members of the columbite family (orthorhombic) commonly contain exsolved niobian-tantalian rutile, or are aggregated with a coprecipitated rutile phase. This assemblage is the Fe, Mn, Nb, Ta-rich counterpart of the Ti-dominant niobian rutile + exsolved titanian columbite pair. The rutile phase is enriched in Fe2+, Ta, Fe3+ and Sn, whereas the orthorhombic phase favors Mn, Nb, Sc, W and Zr. Most samples of the orthorhombic phase are defined as titanian columbite - tantalite; they have low to moderate Ti content, moderately to considerably disordered structure, and convert to highly ordered columbite - tantalite on heating. A minor number of samples of the orthorhombic phase develops the highly ordered structure of wodginite on heating, which identifies them as titanian ixiolite, the disordered counterpart of titanowodginite. These samples are highly disordered in the natural state. They are Ti-rich, with Mn > Fe and Ta > Nb; these features correspond to the composition of natural titanowodginite and of the only titanowodginite synthesized to date. However, subordinate but significant Sn seems to be present in all samples of titanian ixiolite as well as natural titanowodginite, and it may affect the path of ordering. Excess of Ta over the (Fe, Mn)(Nb, Ta)(2) stoichiometry of columbite, characteristic of most compositions of wodginite, may play a significant role. Ordered nuclei potentially present in the bulk of natural disordered phases also may be important. C1 Univ Manitoba, Dept Geol Sci, Winnipeg, MB R3T 2N2, Canada. Canadian Museum Nat, Div Res, Ottawa, ON K1P 6P4, Canada. Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. RP Cerny, P (reprint author), Univ Manitoba, Dept Geol Sci, Winnipeg, MB R3T 2N2, Canada. NR 32 TC 15 Z9 17 U1 0 U2 2 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD APR PY 1998 VL 36 BP 547 EP 561 PN 2 PG 15 WC Mineralogy SC Mineralogy GA 112YT UT WOS:000075525000024 ER PT J AU Wise, MA Cerny, P Falster, AU AF Wise, MA Cerny, P Falster, AU TI Scandium substitution in columbite-group minerals and ixiolite SO CANADIAN MINERALOGIST LA English DT Article DE scandium; columbite; tantalite; ixiolite; granitic pegmatite ID CRYSTAL-CHEMISTRY; NB-BEARING; TA-BEARING; GRANITE; GEOCHEMISTRY; PEGMATITE; TRENDS AB Columbite-group minerals and ixiolite with extremely variable concentrations of scandium are widespread in moderately to highly fractionated rare-element granitic pegmatites. Columbite-group minerals with 1-3 wt.% Sc2O3 are referred to as scandian columbite - tantalite and show degrees of structural order similar to columbite - tantalite lacking Sc. Disordered structures remain orthorhombic and become ordered upon heating. Pseudo-orthorhombic stannian (Sn-rich), titanian (Ti) and wolframian (W) variants of ixiolite may contain as much as 3.7 wt.% Sc2O3 and revert to monoclinic phases upon heating. Similarly, scandian ixiolite that contains Sc in excess of 3.0 and up to 18.8 wt.% Sc2O3 converts from orthorhombic to monoclinic symmetry upon heating and has a stoichiometry that approaches Sc(Nb,Ta)O-4. Scandium-bearing columbite tantalite and ixiolite show similar ranges in Mn/(Mn + Fe) and Ta/(Ta + Nb) values, but noticeably different Sn, Ti and Sc contents. Scandium is incorporated into the columbite and ixiolite structures via the coupled substitution Sc3+ + (Ti,Sn)(4+) = (Fe,Mn)(2+) + (Nb,Ta)(5+); it is strongly partitioned into the (Fe,Mn) site, whereas thr Ti and Sn prefer the (Nb,Ta) site. Within the (Fe,Mn) site, the substitution of Sc for Fe is more prevalent. In most pegmatites, Sc fractionation in columbite - tantalite, stannian ixiolite, titanian ixiolite and wolframian ixiolite is erratic, unlike scandian ixiolite, which shows strong enrichment in Sc with increasing Mn, Ta and Sn. C1 Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. Univ Manitoba, Dept Geol Sci, Winnipeg, MB R3T 2N2, Canada. Univ New Orleans, Dept Geol & Geophys, New Orleans, LA 70148 USA. RP Wise, MA (reprint author), Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. NR 26 TC 17 Z9 18 U1 0 U2 4 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD APR PY 1998 VL 36 BP 673 EP 680 PN 2 PG 8 WC Mineralogy SC Mineralogy GA 112YT UT WOS:000075525000031 ER PT J AU Kensley, B AF Kensley, B TI Estimates of species diversity of free-living marine isopod crustaceans on coral reefs SO CORAL REEFS LA English DT Article DE isopod; crustaceans; diversity; endemism ID SOCIETY-ISLANDS; BORA-BORA; MOOREA; CIROLANIDAE; QUEENSLAND; AUSTRALIA; ASELLOTA AB A core group of isopod crustacean genera appears to be present at many coral reef sites. Within these genera, however, species show high local endemicity. Based on the estimated percentage of endemism for the Atlantic (19% for individual sites, 90% for the tropical western Atlantic as a unit), the Indian Ocean (50%), the eastern-central Pacific (80%), and the western Pacific (40%), it is estimated that there are some 5,000 to 13,000 isopod species in the world's coral reefs, and that some 2,000 to 6,000 of these are endemics. (At present, approximately 4,400 species of marine and 560 species of freshwater isopods have been described.) Based on the crudely estimated relative abundances of other peracaridan crustaceans in coral reefs (compared to isopods), the total diversity of reef amphipods, tanaidaceans, cumaceans, and mysidaceans is approximately 54,500 species. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RP Kensley, B (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 46 TC 20 Z9 22 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD APR PY 1998 VL 17 IS 1 BP 83 EP 88 DI 10.1007/s003380050100 PG 6 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA ZL232 UT WOS:000073412000016 ER PT J AU Zhao, ZJ Pearsall, DM Benfer, RA Piperno, DR AF Zhao, ZJ Pearsall, DM Benfer, RA Piperno, DR TI Distinguishing rice (Oryza sativa poaceae) from wild Oryza species through phytolith analysis, II: Finalized method SO ECONOMIC BOTANY LA English DT Article DE Oryza sativa; phytoliths; Asia, China; discriminant analysis AB Asian I ice is an important grain, not only in its homeland but in many areas of the world. Preliminary studies suggested that phytolith analysis, rite identification of opaline silica bodies, provided a reliable way of identifying lice, especially in situations where preservation of charred botanical remains was poor. Results of this follow-up study, which incorporates all Asian wild Oryza species and a diverse array of traditional Oryza sativa cultivars, confirm? that lice carl be identified with a high level of certainty by the size and qualitative features of a distincitve phytolith, the double-peaked glume cell. C1 Smithsonian Trop Res Inst, APO, AA 34002 USA. Univ Missouri, Dept Anthropol, Columbia, MO 65211 USA. RP Zhao, ZJ (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. NR 19 TC 78 Z9 84 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 1998 VL 52 IS 2 BP 134 EP 145 DI 10.1007/BF02861201 PG 12 WC Plant Sciences SC Plant Sciences GA ZV709 UT WOS:000074333200002 ER PT J AU Runk, JV AF Runk, JV TI Productivity and sustainability of a vegetable ivory palm (Phytelephas aequatorialis, Arecaceae) under three management regimes in northwestern Ecuador SO ECONOMIC BOTANY LA English DT Article DE Phytelephas aequatorialis; vegetable ivory; tagua; Arecaceae; Ecuador; agroforestry ID ASTROCARYUM-MEXICANUM; TROPICAL FOREST; POPULATIONS; IMPACT AB This study examines the predictivity, sustainability, and management of tagua nuts from the palm Phytelephas aequatorialis under three management regimes in northwestern Ecuador. Tagua nuts are used internationally as an ivory substitute and the palm fronds are used locally as roof thatch. Plots were established in control site nad in three local management regimes: pure tagua groves; stands with tagua and cacao in an agroforestry system; and tagua groves where the undergrowth is cleared and old fronds removed. Data were collected for one year and local extractors were interviewed about their tagua management. Palm demography indicates heavy management with few subadult individuals and many more adult females than males. Productivity analyses do not demonstrate the influence of any ne environmental variable on leaf or infructescence productivity. The pure tagua grove is the management regime most conducive to tagua sustainability. The sustainability results are underscored by the extractive methodology, where local extractors maximize tagua collected while minimizing collection time. These results are incorporated into management recommendations to foster tagua extraction while ensuring its sustainability and future use. C1 Duke Univ, Sch Environm, Durham, NC 27708 USA. RP Runk, JV (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 38 TC 22 Z9 23 U1 0 U2 4 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 1998 VL 52 IS 2 BP 168 EP 182 DI 10.1007/BF02861205 PG 15 WC Plant Sciences SC Plant Sciences GA ZV709 UT WOS:000074333200005 ER PT J AU Eberhard, WG Huber, BA Rodriguez, RL Briceno, RD Salas, I Rodriguez, V AF Eberhard, WG Huber, BA Rodriguez, RL Briceno, RD Salas, I Rodriguez, V TI One size fits all? Relationships between the size and degree of variation in genitalia and other body parts in twenty species of insects and spiders SO EVOLUTION LA English DT Article DE allometry; genitalia; sexual selection ID COPULATORY COURTSHIP; SPERM-STORAGE; MATE CHOICE; COLEOPTERA; SCARABAEIDAE; DIMORPHISM; ALLOMETRY; ARANEAE; DISPLAY; EVOLUTIONARY AB Hypotheses regarding the function of elaborate male genitalia were tested in a sample of insects and spiders by comparing their allometric values (slopes in log-log regressions on indicators of body size) with those of other body parts. Male genitalia consistently had lower slopes than other body parts. Perhaps as a consequence of this pattern, genitalic size also tended, though less consistently, to have lower coefficients of variation than did the size of other body parts. The morphological details of coupling between males and females in several species clearly indicated that selection favoring mechanical fit is not responsible for these trends. Sexual selection on male courtship structures that are brought into contact with females in precise ways may favor relatively low allometric values, in contrast to the high values seen in the other sexually selected characters (usually visual display devices) that have been studied previously, because a female's own size will influence her perception of the contact courtship devices of a male. C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Costa Rica, Escuela Biol, San Jose, Costa Rica. RP Smithsonian Trop Res Inst, Balboa, Panama. EM weberhar@cariari.ucr.ac.cr NR 74 TC 244 Z9 248 U1 5 U2 49 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 APR PY 1998 VL 52 IS 2 BP 415 EP 431 DI 10.2307/2411078 PG 17 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA ZM270 UT WOS:000073521700011 ER PT J AU West, SA Herre, EA AF West, SA Herre, EA TI Stabilizing selection and variance in fig wasp sex ratios SO EVOLUTION LA English DT Article DE fig wasps; intensity of selection; sex ratio; stabilizing selection; variance ID LOCAL MATE COMPETITION; DEVELOPMENTAL MORTALITY; DROSOPHILA-MELANOGASTER; INDEPENDENT CONTRASTS; GENETIC-VARIABILITY; PARASITIC WASP; EVOLUTION; ALLOCATION; MUTATION; BALANCE AB Theory predicts that the phenotypic variance observed in a trait subject to stabilizing selection should be negatively correlated with the trait's impact on fitness. However, this relationship has rarely been tested directly. The offspring sex ratios produced by pollinating fig wasp foundresses upon entrance to a fruit and oviposition alone (single foundress sex ratios) are subject to stabilizing selection because too many males reduce the total number of dispersing females and too few males will result in unmated females or complete loss of the brood. Furthermore, we argue that the impact on fitness of, and therefore the intensity of stabilizing intensity on, single foundress sex ratios are correlated to how frequently a species produces single foundress broods in nature. Specifically, the intensity of stabilizing selection will be greater in species that encounter single foundress broods more frequently, both because the trait is expressed more often and because fitness shows a greater sensitivity to variation (narrower fitness profile) when that trait is expressed. Across 16 species of Panamanian pollinating fig wasps the phenotypic variance in single foundress sex ratios was negatively correlated with the frequency with which that species encounters single foundress broods in nature. In addition, a formal comparative analysis based upon a molecular phylogeny of the wasps gave results that were the same as when species were used as independent data points. C1 Smithsonian Trop Res Inst, Bilboa, Panama. Univ Edinburgh, Inst Cell Anim & Populat Biol, Edinburgh EH9 3JT, Midlothian, Scotland. RP West, SA (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Bilboa, Panama. EM Stu.West@ed.ac.uk RI West, Stuart/M-3608-2014 OI West, Stuart/0000-0003-2152-3153 NR 68 TC 72 Z9 76 U1 3 U2 15 PU SOC STUDY EVOLUTION PI LAWRENCE PA 810 E 10TH STREET, LAWRENCE, KS 66044 USA SN 0014-3820 J9 EVOLUTION JI Evolution PD APR PY 1998 VL 52 IS 2 BP 475 EP 485 DI 10.2307/2411083 PG 11 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA ZM270 UT WOS:000073521700016 ER PT J AU Chapman, MG Zimbelman, JR AF Chapman, MG Zimbelman, JR TI Corona associations and their implications for Venus SO ICARUS LA English DT Article ID RESURFACING HISTORY; GLOBAL DISTRIBUTION; THERMAL EVOLUTION; MAGELLAN DATA; MANTLE FLOW; MORPHOLOGY; FEATURES; ORIGIN; CLASSIFICATION; VOLCANISM AB Geologic mapping principles were applied to determine genetic relations between coronae and surrounding geomorphologic features within two study areas in order to better understand venusian coronae. The study areas contain coronae in a cluster versus a contrasting chain and are (1) directly west of Phoebe Regio (quadrangle V-40; centered at latitude 15 degrees S, longitude 250 degrees) and (2) west of Asteria and Beta Regiones (between latitude 23 degrees N, longitude 239 degrees and latitude 43 degrees N, longitude 275 degrees). Results of this research indicate two groups of coronae on Venus: (1) those that are older and nearly coeval with regional plains, and occur globally; and (2) those that are younger and occur between Beta, Atla, and Themis Regiones or along extensional rifts elsewhere, sometimes showing systematic age progressions. Mapping relations and Earth analogs suggest that older plains coronae may be related to a near-global resurfacing event perhaps initiated by a mantle superplume or plumes. Younger coronae of this study that show age progression may be related to (1) a tectonic junction of connecting rifts resulting from local mantle upwelling and spread of a quasi-stationary hotspot plume, and (2) localized spread of post-plains volcanism. We postulate that on Venus most of the young, post-resurfacing coronal plumes may be concentrated within an area defined by the bounds of Beta, Atla, and Themis Regiones. (C) 1998 Academic Press. C1 US Geol Survey, Flagstaff, AZ 86001 USA. Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, Washington, DC 20560 USA. RP Chapman, MG (reprint author), US Geol Survey, 2255 N Gemini Dr, Flagstaff, AZ 86001 USA. EM mchapman@flagmail.wr.usgs.gov NR 55 TC 10 Z9 10 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 1998 VL 132 IS 2 BP 344 EP 361 DI 10.1006/icar.1998.5899 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZP735 UT WOS:000073783200009 ER PT J AU Chai, P Chang, AC Dudley, R AF Chai, P Chang, AC Dudley, R TI Flight thermogenesis and energy conservation in hovering hummingbirds SO JOURNAL OF EXPERIMENTAL BIOLOGY LA English DT Article DE flight energetics; hovering flight; hummingbirds; mechanical power output; metabolic heat production; muscle mechanical efficiency; oxygen consumption; temperature; thermoregulation; Archilochus colubris ID INSECT FLIGHT; OXYGEN-CONSUMPTION; BODY-TEMPERATURE; AERODYNAMICS; TORPOR; THERMOREGULATION; ENERGETICS; METABOLISM; BIRDS; CONTRIBUTES AB As the smallest homeotherms, hummingbirds suffer from low thermal inertia and high heat loss. Flapping flight is energetically expensive, and convective cooling due to wing and air movements could further exacerbate energy drain. Energy conservation during flight is thus profoundly important for hummingbirds. The present study demonstrates that heat produced by flight activity can contribute to thermoregulatory requirements in hovering hummingbirds. The rate of oxygen consumption, as an indicator of metabolic cost, was measured during hover-feeding and compared with that during perch-feeding. In hover-feeding, oxygen consumption increased only moderately between 35 and 5 degrees C in contrast to the sharp increase during perch-feeding over the same temperature range. This result suggests that heat produced by contraction of the flight muscles substituted for regulatory thermogenesis to accommodate for heat loss during temperature. With declining air temperatures, the mechanical power requirements of hovering decreased slightly, but metabolic costs increased moderately. As a result, the mechanical efficiency of the muscle in converting metabolic power to mechanical power was I educed. Changes in wingbeat kinematics also accompanied the reduction in muscle efficiency. Wingbeat frequency increased but stroke amplitude decreased when hovering in the cold, suggesting thermoregulatory roles for the flight muscles. Hovering hummingbirds modulated their wingbeat frequency within a narrow range, reflecting the physical constraints of tuning to a natural resonant frequency with an elastic restoring force. We hypothesize that, by forcing the resonant system of the wings and thorax to oscillate at different frequencies, muscle contraction in the cold generates more heat at the expense of mechanical efficiency. This mechanism of modulating the efficiency of muscle contraction and heat production allows flying hummingbirds to achieve energy conservation at low air temperatures. C1 Univ Texas, Dept Zool, Austin, TX 78712 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Chai, P (reprint author), Univ Texas, Dept Zool, Austin, TX 78712 USA. EM pengchai@utxvms.cc.utexas.edu NR 45 TC 30 Z9 30 U1 2 U2 19 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND SN 0022-0949 EI 1477-9145 J9 J EXP BIOL JI J. Exp. Biol. PD APR PY 1998 VL 201 IS 7 BP 963 EP 968 PG 6 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZL570 UT WOS:000073447600007 ER PT J AU Dudley, R AF Dudley, R TI Atmospheric oxygen, giant Paleozoic insects and the evolution of aerial locomotor performance SO JOURNAL OF EXPERIMENTAL BIOLOGY LA English DT Article DE atmosphere; density; flight; gigantism; hyperoxia; insect; oxygen; Paleozoic ID TRIASSIC MASS EXTINCTION; DROSOPHILA-MELANOGASTER; PHANEROZOIC TIME; SUPEROXIDE-DISMUTASE; OXIDATIVE DAMAGE; GAS-MIXTURES; LIFE-SPAN; FLIGHT; HYPEROXIA; HYPOXIA AB Uniformitarian approaches to the evolution of terrestrial locomotor physiology and animal flight performance have generally presupposed the constancy of atmospheric composition. Recent geophysical data as well as theoretical models suggest that, to the contrary, both oxygen and carbon dioxide concentrations have changed dramatically during defining periods of metazoan evolution. Hyperoxia in the late Paleozoic atmosphere may have physiologically enhanced the initial evolution of tetrapod locomotor energetics; a concurrently hyperdense atmosphere would have augmented aerodynamic force production in early flying insects, Multiple historical origins of vertebrate flight also correlate temporally with geological periods of increased oxygen concentration and atmospheric density. Arthropod as well as amphibian gigantism appear to have been facilitated by a hyperoxic Carboniferous atmosphere and were subsequently eliminated by a late Permian transition to hypoxia, For extant organisms, the transient, chronic and ontogenetic effects of exposure to hyperoxic gas mixtures are poorly understood relative to contemporary understanding of the physiology of oxygen deprivation. Experimentally, the biomechanical and physiological effects of hyperoxia on animal flight performance can be decoupled through the use of gas mixtures that vary in density and oxygen concentration. Such manipulations permit both paleophysiological simulation of ancestral locomotor performance and an analysis of maximal flight capacity in extant forms. C1 Univ Texas, Dept Zool, Austin, TX 78712 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Dudley, R (reprint author), Univ Texas, Dept Zool, Austin, TX 78712 USA. EM r_dudley@utxvms.cc.utexas.edu NR 87 TC 132 Z9 137 U1 1 U2 46 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND SN 0022-0949 J9 J EXP BIOL JI J. Exp. Biol. PD APR PY 1998 VL 201 IS 8 BP 1043 EP 1050 PG 8 WC Biology SC Life Sciences & Biomedicine - Other Topics GA ZP632 UT WOS:000073772900001 PM 9510518 ER PT J AU Allen, LA Habbal, SR Hu, YQ AF Allen, LA Habbal, SR Hu, YQ TI Thermal coupling of protons and neutral hydrogen in the fast solar wind SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID 2-FLUID MODEL; ENERGY-FLOW; ULYSSES; ACCELERATION; TEMPERATURES; LATITUDES; CORONA; REGION; WAVES AB We investigate the coupling between neutral hydrogen atoms and protons in the corona for a range of proton temperatures reaching a maximum of 6 x 10(6) K, as recently inferred from observations of the Ly alpha spectral line profiles by Kohl et al. [1996]. We adopt the approach used by Olsen et al. [1994], whereby the neutral hydrogen atoms are treated as test particles in a background electron-proton solar wind. Charge exchange between neutrals and protons, radiative recombination, collisional ionization of the neutrals, and the effects of Alfven waves, described by a; single frequency or a spectrum, are included in the model. The computations show that an anisotropy in the neutral hydrogen temperature develops in the directions parallel and perpendicular to the magnetic field within 2-3 R-S for solar wind conditions, consistent with observational constraints of the fast wind. Although T-H(perpendicular to) exceeds T-H(parallel to) (similar to T-p) in the inner coronal the anisotropy decreases as the peak proton temperature increases, with a temperature difference of <8 x 10(5) K when the protons reach 6 x 10(6) K. We find that the effective temperature T-H(eff),(perpendicular to), incorporating both random and wave motions of the neutral hydrogen, and the calculated Ly alpha line profile are independent of wave frequency. The dominant contribution to the profiles comes from T-H(eff)(perpendicular to) at the point of closest approach to the Sun along to line of sight (LOS), although the widths of the profiles are significantly narrawed by non-90 degrees scattering along the LOS, broadened by outflow velocity, and narrowed or broadened by steep temperature gradients along the LOS. The proton and neutral hydrogen effective temperatures and velocities are comparable below similar to 3 R-S, thus implying that the measured Ly alpha profiles are equivalent to measurements of the velocity distribution of protons in that region. Beyond similar to 3 R-S, holvever, T-H(eff)(perpendicular to) is found to be significantly lower than T-p(eff), and the measurement of T-H(eff(perpendicular to) provides a lower limit for T-p(eff) there. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Sci & Technol China, Hefei 230026, Anhui, Peoples R China. RP Allen, LA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM lallen@cfa.harvard.edu; shabbal@cfa.harvard.edu; huyq@ess.ustc.edu.cn NR 34 TC 49 Z9 49 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1998 VL 103 IS A4 BP 6551 EP 6569 DI 10.1029/97JA03435 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZF972 UT WOS:000072951700008 ER PT J AU Yamauchi, Y Tokumaru, M Kojima, M Manoharan, PK Esser, R AF Yamauchi, Y Tokumaru, M Kojima, M Manoharan, PK Esser, R TI A study of density fluctuations in the solar wind acceleration region SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTER-PLANETARY SCINTILLATIONS; HELIOSPHERIC CURRENT SHEET; INTERPLANETARY SCINTILLATION; ALFVEN WAVES; SCATTERING OBSERVATIONS; PHYSICAL-PROPERTIES; POWER SPECTRUM; CORONAL HOLE; TURBULENCE; SUN AB Interplanetary scintillation (IFS) measurements of the density fluctuations in the fast and slow solar wind were made at 2 GHz and 8 GHz in 1994 at the Kashima. Space Research Center, Communications Research Laboratory, Using: the observations which cover the distance range from 5 to 76 solar radii (R-s), we investigate the radial evolution of the dissipation scale length of the density fluctuations, the so-called; inner scale." Our IFS observations reveal that the inner scale shows different radial profiles between the inside and outside of the acceleration region, The size of the inner scale outside 25 R-s increases linearly with radial distance, showing: good agreement with previous observations made at r greater than or equal to greater than or equal to 50 R-s, The inner scale inside 25 R-s, on the other hand, deviates from the linear relation, We simulate the radial variation of the inner scale using-a solar wind acceleration model and then compare the results to that of the observed inner scale, We find that. in the low-speed solar wind, the radial profile of the computed inner scale is in good agreement with that of the observed inner scale and that the salar wind acceleration causes the deviation of the inner scale from a linear relation, However, in the high-speed wind, we cannot reproduce the radial profile of the observed inner scale with the acceleration model, even though the line-of-sight integration effect on IFS measurements is taken into account, We propose that this disagreement is due to the density and magnetic field fluctuations not being correlated in the high-speed solar wind, as shown at greater heliocentric distances by Hellos measurements. C1 Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Japan. Tata Inst Fundamental Res, Radio Astron Lab, Udhagamandalam 643001, India. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Yamauchi, Y (reprint author), Nagoya Univ, Solar Terr Environm Lab, Honohara 3-13, Toyokawa, Japan. EM yamauchi@stelab.nagoya-u.ac.jp; tokumaru@stelab.nagoya-u.ac.jp; kojima@stelab.nagoya-u.ac.jp; mano@racooty.ernet.in; esser@cfassp32.harvard.edu NR 53 TC 28 Z9 28 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1998 VL 103 IS A4 BP 6571 EP 6583 DI 10.1029/97JA03598 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZF972 UT WOS:000072951700009 ER PT J AU Neufeld, MJ AF Neufeld, MJ TI The Luftwaffe: Creating the operational air war, 1918-1940 SO JOURNAL OF MILITARY HISTORY LA English DT Book Review C1 Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. RP Neufeld, MJ (reprint author), Smithsonian Inst, Natl Air & Space Museum, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU SOC MILITARY HISTORY PI LEXINGTON PA C/O VIRGINIA MILITARY INST, GEORGE C MARSHALL LIBRARY, LEXINGTON, VA 24450-1600 USA SN 0899-3718 J9 J MILITARY HIST JI J. Mil. Hist. PD APR PY 1998 VL 62 IS 2 BP 421 EP 423 DI 10.2307/120753 PG 3 WC History SC History GA ZF818 UT WOS:000072936300037 ER PT J AU Eberhard, WG AF Eberhard, WG TI Reproductive behavior of Glyphidops flavifrons and Nerius plurivitatus (Diptera, Neriidae) SO JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY LA English DT Article ID FEMALE AB Males of the neriid flies Glyphidops flavifrons and Nerius plurivitatus mated with females near oviposition sites. Males fought over females, probably using their armed front legs. Smaller males employed an alternative, harassing tactic that delayed copulation by other males. There was little precopulatory courtship, and females usually mated readily. But relatively elaborate leg waving, and complex genitalic tapping, stroking and tugging occurred during copulation. The movements of both legs and genitalia differed between species. Functional interpretations of several genitalic structures that may stimulate the female and/or anchor the male's genitalia inside her are presented. 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 20 TC 12 Z9 12 U1 0 U2 0 PU KANSAS ENTOMOLOGICAL SOC PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0022-8567 J9 J KANSAS ENTOMOL SOC JI J. Kans. Entomol. Soc. PD APR PY 1998 VL 71 IS 2 BP 89 EP 107 PG 19 WC Entomology SC Entomology GA 187PV UT WOS:000079796400002 ER PT J AU Mendez, V Briceno, RD Eberhard, WG AF Mendez, V Briceno, RD Eberhard, WG TI Functional significance of the capitate supra-fronto-orbital bristles of male medflies (Ceratitis capitata) (Diptera, Tephritidae) SO JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY LA English DT Article AB Experimental removal of the sexually dimorphic supra-fronto-orbital bristles from male Ceratitis capitata lowered the chances that courting males would succeed in mounting females. Bristle removal did not affect male courtship behavior, and females often did not contact male bristles, so the male bristles probably function as visual display devices, despite the surprising fact that neither placement of the bristles nor courtship behavior are appropriate to display either the bristles' exaggerated length or the expansions at their tips to full effect. Indirect evidence suggests that male eye colors are also important in courtship, but that bristle asymmetry is not. C1 Univ Costa Rica, Escuela Biol, San Jose, Costa Rica. Smithsonian Trop Res Inst, Balboa, Panama. RP Mendez, V (reprint author), Univ Costa Rica, Escuela Biol, Ciudad Univ, San Jose, Costa Rica. NR 13 TC 12 Z9 12 U1 1 U2 3 PU KANSAS ENTOMOLOGICAL SOC PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0022-8567 J9 J KANSAS ENTOMOL SOC JI J. Kans. Entomol. Soc. PD APR PY 1998 VL 71 IS 2 BP 164 EP 174 PG 11 WC Entomology SC Entomology GA 187PV UT WOS:000079796400007 ER PT J AU Roubik, DW AF Roubik, DW TI Grave-robbing by male Eulaema (Hymenoptera, Apidae): Implications for euglossine biology SO JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY LA English DT Article ID ORCHID-BEES APIDAE AB Field observations and published data suggest euglossine males collect volatile substances that later serve as "good genes" markers to potential mates. Because this synthesis is just emerging, two field observations made in the Ecuadorian Amazon and Panama are relevant, supplementing other data on Eulaema meriana. Six males were found attempting to extract and sequester chemicals of a recently killed male in the Yasuni National Park, Ecuador. No female came to the dead male. Three dead males of this species, placed in the field in Panama, attracted one male but no females. Further, males had qualitatively the same mandibular gland odor but perceptibly different hind tibial odors. These data are explained by considering the male euglossine chemical collecting behavior one that ultimately demonstrates bee longevity, foraging ability and, in the context of male mating territory, suitability as a mate. C1 Smithsonian Trop Res Inst, Balboa, Panama. RP Roubik, DW (reprint author), Unit 0948, APO, AA 34002 USA. NR 10 TC 7 Z9 7 U1 0 U2 1 PU KANSAS ENTOMOLOGICAL SOC PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0022-8567 J9 J KANSAS ENTOMOL SOC JI J. Kans. Entomol. Soc. PD APR PY 1998 VL 71 IS 2 BP 188 EP 191 PG 4 WC Entomology SC Entomology GA 187PV UT WOS:000079796400011 ER PT J AU Riley, SM AF Riley, SM TI The unexpected salami. SO LIBRARY JOURNAL LA English DT Book Review C1 Smithsonian Inst Lib, Washington, DC 20560 USA. RP Riley, SM (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 1 PY 1998 VL 123 IS 6 BP 125 EP 125 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA ZE123 UT WOS:000072760000231 ER PT J AU Bermingham, E Moritz, C AF Bermingham, E Moritz, C TI Comparative phylogeography: concepts and applications SO MOLECULAR ECOLOGY LA English DT Editorial Material ID POPULATION-GENETICS C1 Smithsonian Trop Res Inst, Balboa, Panama. Univ Queensland, Dept Zool, St Lucia, Qld 4072, Australia. RP Bermingham, E (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. RI Moritz, Craig/A-7755-2012 NR 20 TC 227 Z9 238 U1 4 U2 40 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD APR PY 1998 VL 7 IS 4 BP 367 EP 369 DI 10.1046/j.1365-294x.1998.00424.x PG 3 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA ZP873 UT WOS:000073797200001 ER PT J AU Bermingham, E Martin, AP AF Bermingham, E Martin, AP TI Comparative mtDNA phylogeography of neotropical freshwater fishes: testing shared history to infer the evolutionary landscape of lower Central America SO MOLECULAR ECOLOGY LA English DT Article DE dispersal; freshwater fishes; historical biogeography; mitochondrial DNA; neotropics; speciation ID EFFECTIVE POPULATION-SIZE; DNA-SEQUENCE DATA; MITOCHONDRIAL-DNA; GENE FLOW; REGIONAL PROCESSES; TREE TOPOLOGIES; BIOGEOGRAPHY; PANAMA; SYSTEMATICS; PHYLOGENIES AB Historical biogeography seeks to explain contemporary distributions of taxa in the context of intrinsic biological and extrinsic geological and climatic factors. To decipher the relative importance of biological characteristics vs. environmental conditions, it is necessary to ask whether groups of taxa with similar distributions share the same history of diversification. Because all of the taxa will have shared the same climatic and geological history, evidence of shared history across multiple species provides an estimate of the role of extrinsic factors in shaping contemporary biogeographic patterns. Similarly, differences in the records of evolutionary history across species will probably be signatures of biological differences. In this study, we focus on inferring the evolutionary history for geographical populations and closely related species representing three genera of primary freshwater fishes that are widely distributed in lower Central America (LCA) and northwestern Colombia. Analysis of mitochondrial gene trees provides the opportunity for robust tests of shared history across taxa. Moreover, because mtDNA permits inference of the temporal scale of diversification we can test hypotheses regarding the chronological development of the Isthmian corridor linking North and South America. We have focused attention on two issues. First, we show that many of the distinct populations of LCA fishes diverged in a relatively brief period of time thus limiting the phylogenetic signal available for tests of shared history. Second, our results provide reduced evidence of shared history when all drainages are included in the analysis because of inferred dispersion events that obscure the evolutionary history among drainage basins. When we restrict the analysis to areas that harbour endemic mitochondrial lineages, there is evidence of shared history across taxa. We hypothesize that there were two to three distinct waves of invasion into LCA from putative source populations in northwestern Colombia. The first probably happened in the late Miocene, prior to the final emergence of the Isthmus in the mid-Pliocene; the second was probably coincident with the rise of the Isthmus in the mid-Pliocene, and the third event occurred more recently, perhaps in the Pleistocene. In each case the geographical scale of the dispersion of lineages was progressively more limited, a pattern we attribute to the continuing development of the landscape due to orogeny and the consequent increase in the insularization of drainage basins. Thus, the fisheye view of LCA suggests a complex biogeographic history of overlaid cycles of colonization, diversification, sorting and extinction of lineages. C1 Smithsonian Trop Res Inst, APO, AA 34002 USA. Smithsonian Trop Res Inst, Balboa, Panama. Univ Nevada, Dept Biol, Las Vegas, NV 89154 USA. RP Bermingham, E (reprint author), Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. EM eb@naos.si.edu NR 75 TC 228 Z9 244 U1 4 U2 31 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD APR PY 1998 VL 7 IS 4 BP 499 EP 517 DI 10.1046/j.1365-294x.1998.00358.x PG 19 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA ZP873 UT WOS:000073797200012 PM 9628002 ER PT J AU Fleischer, RC McIntosh, CE Tarr, CL AF Fleischer, RC McIntosh, CE Tarr, CL TI Evolution on a volcanic conveyor belt: using phylogeographic reconstructions and K-Ar-based ages of the Hawaiian Islands to estimate molecular evolutionary rates SO MOLECULAR ECOLOGY LA English DT Article DE adaptive radiation; drepanidines; Hawaiian Drosophila; Hawaiian Islands; Laupala; molecular rate calibration; phylogeography ID ALCOHOL-DEHYDROGENASE LOCUS; MITOCHONDRIAL-DNA EVOLUTION; NUCLEOTIDE SUBSTITUTION; PHYLOGENETIC ANALYSIS; METABOLIC-RATE; TIME SCALE; DROSOPHILA; SEQUENCES; DIVERGENCE; ORIGIN AB The Hawaiian Islands form as the Pacific Plate moves over a 'hot spot' in the earth's mantle where magma extrudes through the crust to build huge shield volcanos. The islands subside and erode as the plate carries them to the north-west, eventually to become coral atolls and seamounts. Thus islands are ordered linearly by age, with the oldest islands in the north-west (e.g. Kauai at 5.1 Ma) and the youngest in the south-east (e.g. Hawaii at 0.43 Ma). K-Ar estimates of the date of an island's formation provide a maximum age for the taxa inhabiting the island. These ages can be used to calibrate rates of molecular change under the following assumptions: (i) K-Ar dates are accurate; (ii) tree topologies show that derivation of taxa parallels the timing of island formation; (iii) populations do not colonize long after island emergence; (iv) the coalescent point for sister taxa does not greatly predate the formation of the colonized younger island; (v) saturation effects and (vi) among-lineage rate variation are minimal or correctable; and (vii) unbiased standard errors of distances and regressions can be estimated from multiple pairwise comparisons. We use the approach to obtain overall corrected rate calibrations for: (i) part of the mitochondrial cytochrome b gene in Hawaiian drepanidines (0.016 sequence divergence/Myr); (ii) the Yp1 gene in Hawaiian Drosophila (0.019/Myr Kambysellis et al. 1995); and (iii) parts of the mitochondrial 12S and 16S rRNA and tRNA(val) in Laupala crickets (0.024-0.102/Myr, Shaw 1996). We discuss the reliability of the estimates given the assumptions (i-vii) above and contrast the results with previous calibrations of Adh in Hawaiian Drosophila and chloroplast DNA in lobeliods. C1 Smithsonian Inst, Natl Zool Pk, Genet Mol Lab, Washington, DC 20008 USA. Penn State Univ, Dept Biol, University Pk, PA 16802 USA. Penn State Univ, Inst Mol Evolut Genet, University Pk, PA 16802 USA. RP Fleischer, RC (reprint author), Smithsonian Inst, Natl Zool Pk, Genet Mol Lab, Washington, DC 20008 USA. NR 75 TC 343 Z9 355 U1 6 U2 52 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD APR PY 1998 VL 7 IS 4 BP 533 EP 545 DI 10.1046/j.1365-294x.1998.00364.x PG 13 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA ZP873 UT WOS:000073797200014 PM 9628004 ER PT J AU Martin, AP Bermingham, E AF Martin, AP Bermingham, E TI Systematics and evolution of lower Central American cichlids inferred from analysis of cytochrome b gene sequences SO MOLECULAR PHYLOGENETICS AND EVOLUTION LA English DT Article DE cytochrome b; Central America; Cichlasoma; systematics; adaptive radiation ID MITOCHONDRIAL-DNA; PHYLOGENETIC-RELATIONSHIPS; RATES; FISHES; CONVERGENCE; TANGANYIKA; MAMMALS; MALAWI; SHARKS AB Central American cichlids allied to the genus "Cichlasoma" are thought to be of South American ancestry. The group has apparently undergone extensive morphological, ecological, and behavioral differentiation in Central America following colonization. Uncertainties regarding the systematics of the group and the timing of colonization complicate interpretation of the biological history of cichlids in Central America. We determined complete cytochrome b gene sequences for 54 individual cichlids representing 21 species to test hypotheses regarding the time of origin and pattern of diversification of lower Central American cichlids. The data also bear on issues relating to the systematics and taxonomy of heroine cichlids. Our results suggest that cichlids have been in Central America since the middle to late Miocene. Moreover, the data provide evidence of a rapid radiation early in the history of the group. Similar ecomorphological types have evolved multiple times. Inferences of convergent morphological evolution may, in part, explain a lack of concordance between the mitochondrial gene tree and previous inferences of phylogenetic relationships based on observable characteristics. Phylogenetic inferences based on the molecular data provide support for the recognition of "sections" [erected by Regan (1905) and others] as distinct genera and suggest that thorough revision of Central American cichlids is necessary before the extent of biological diversity within the group can be fully appreciated. (C) 1998 Academic Press. C1 Smithsonian Trop Res Inst, Naos Marine Lab Unit 0948, APO, AA 34002 USA. Univ Nevada, Dept Biol Sci, Las Vegas, NV 89154 USA. RP Martin, AP (reprint author), Smithsonian Trop Res Inst, Naos Marine Lab Unit 0948, APO, AA 34002 USA. NR 41 TC 76 Z9 80 U1 1 U2 7 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 APR PY 1998 VL 9 IS 2 BP 192 EP 203 DI 10.1006/mpev.1997.0461 PG 12 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA ZH434 UT WOS:000073108700002 PM 9562979 ER PT J AU Osten, RA Saar, SH AF Osten, RA Saar, SH TI Physical properties of active stars and stellar systems SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars, activity; binaries, general; stars, fundamental parameters; stars, late-type; stars, rotation ID SOLAR-TYPE STARS; OBJECTIVE-PRISM DISCOVERIES; EINSTEIN-SLEW SURVEY; RADIAL-VELOCITIES; EVOLVED STARS; NORTHERN SKY; BINARY STARS; COOL STARS; SPECTROSCOPY; PHOTOMETRY AB We study spectra of 18 active stars and stellar systems, drawn from lists of known active binaries or newly discovered extreme-ultraviolet and soft X-ray sources. Using spectral synthesis and template modelling, we measure (often for the first time) a variety of physical properties of the stars, including spectral types, luminosities and v sin i values. We report direct observation of previously undetected secondary components in three systems, and refine the orbital elements for two of these (HR 7275 and HD 217344). C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. RP Osten, RA (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 58, Cambridge, MA 02138 USA. NR 59 TC 27 Z9 27 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 1 PY 1998 VL 295 IS 2 BP 257 EP 264 DI 10.1046/j.1365-8711.1998.01121.x PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZH546 UT WOS:000073121900006 ER PT J AU Depriest, PT Gale, BW AF Depriest, PT Gale, BW TI New combinations in Parmelioid Genera (Ascomycotina : Parmeliaceae) SO MYCOTAXON LA English DT Article AB In preparation for updating Mason E. Hale's "List of Epithets in the Parmelioid Genera," we have identified 27 species epithets that need transfer into generic segregates from Parmelia s. late. Most of these epithets were retained in Parmelia when other members of their groups were transferred into one of the more than thirty generic segregates described or resurrected in the past twenty-five years. New combinations are proposed in ten genera of the lichen family Parmeliaceae: Flavoparmelia, Hypotrachyna, Myelochroa, Neofuscelia, Paraparmelia, Parmelinopsis, Parmeliopsis, Parmotrema, Punctelia, and Rimeliella. C1 Natl Museum Nat Hist, Dept Bot, Smithsonian Inst, Washington, DC 20560 USA. RP Natl Museum Nat Hist, Dept Bot, Smithsonian Inst, MRC-166, Washington, DC 20560 USA. RI DePriest, Paula/K-6633-2015 NR 6 TC 9 Z9 11 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 1998 VL 67 BP 201 EP 206 PG 6 WC Mycology SC Mycology GA 101MY UT WOS:000074873800017 ER PT J AU Depriest, PT Hale, BW AF Depriest, PT Hale, BW TI A validated species and a new combination in Parmotrema (Ascomycotina : Parmeliaceae) SO MYCOTAXON LA English DT Article AB We have identified two nomenclatural problems in the genus Parmotrema. The name Parmotrema incrassatum Hale was invalidly published since it lacked both a Latin description and type designation, and Parmotrema michauxianum (Zahlbr.) Hale is a synonym since there is an earlier epithet available for that species. We provide validation of the first species and a new combination for the second to resolve these nomenclatural issues. C1 Natl Museum Nat Hist, Dept Bot, Smithsonian Inst, Washington, DC 20560 USA. RP Natl Museum Nat Hist, Dept Bot, Smithsonian Inst, MRC-166, Washington, DC 20560 USA. RI DePriest, Paula/K-6633-2015 NR 11 TC 4 Z9 6 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 1998 VL 67 BP 207 EP 209 PG 3 WC Mycology SC Mycology GA 101MY UT WOS:000074873800018 ER PT J AU Tyree, MT Velez, V Dalling, JW AF Tyree, MT Velez, V Dalling, JW TI Growth dynamics of root and shoot hydraulic conductance in seedlings of five neotropical tree species: scaling to show possible adaptation to differing light regimes SO OECOLOGIA LA English DT Article DE hydraulic conductance; root; shoot; growth dynamics; neotropical tree seedlings ID HIGH-PRESSURE FLOWMETER; 2 DESERT SUCCULENTS; ACER-SACCHARUM; WATER RELATIONS; ARCHITECTURE; RESISTANCE; CONDUCTIVITY; PATTERNS; FOREST; PANAMA AB The dynamics of growth (shoot and root dry weights, surface areas, hydraulic conductances, and root length) were measured in seedlings of five neotropical tree species aged 4-16 months. The species studied included two light-demanding pioneers (Miconia argentea and Apeiba membranacea) and three shade-tolerant young-or old-forest species (Pouteria reticulata, Gustavia superba, and Trichilia tuberculata). Growth analysis revealed that shoot and root dry weights and hydraulic conductances and leaf area all increased exponentially with time. Alternative methods of scaling measured parameters to reveal differences that might explain adaptations to microsites are discussed. Scaling root conductance to root surface area or root length revealed a few species differences but nothing that correlated with adaptation to light regimes. Scaling of root surface area or root length to root dry weight revealed that pioneers produced significantly more root area and length per gram dry weight investment than shade-tolerant species. Scaling of root and shoot hydraulic conductances to leaf area and scaling of root conductance to root;dry weight and shoot conductance to shoot dry weight also revealed that pioneers were significantly more conductive to water than shade-tolerant species. The advantages of scaling hydraulic parameters to leaf surface area are discussed in terms of the Ohm's law analogue of water flow in plants. C1 US Forest Serv, USDA, Aiken Forestry Sci Lab, S Burlington, VT 05402 USA. Smithsonian Trop Res Inst, Balboa, Panama. RP Tyree, MT (reprint author), US Forest Serv, USDA, Aiken Forestry Sci Lab, POB 968, S Burlington, VT 05402 USA. NR 24 TC 114 Z9 120 U1 4 U2 24 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0029-8549 J9 OECOLOGIA JI Oecologia PD APR PY 1998 VL 114 IS 3 BP 293 EP 298 DI 10.1007/s004420050450 PG 6 WC Ecology SC Environmental Sciences & Ecology GA ZL119 UT WOS:000073400700001 PM 28307771 ER PT J AU Phillips, TL DiMichele, WA AF Phillips, TL DiMichele, WA TI A transect through a clastic-swamp to peat-swamp ecotone in the Springfield Coal, middle Pennsylvanian age of Indiana, USA SO PALAIOS LA English DT Article ID APPALACHIAN BASIN; PALEOECOLOGY; BED; LEPIDOSTROBUS; LYCOSPORA AB Permineralized fossil plants in coal balls were collected along a kilometer transect through an organic-rich shale in the Springfield Coal in southwestern Indiana. The organic shale is an upper bench of the Springfield Coal in art area where the coal is split into an upper and lower bench by a complex system of clastics that originated as a splay. The elastic wedge, described as the Folsomville Member/Leslie Cemetery paleochannel, is up to 6 km wide and 15 m thick. The transect begins approximately 100 m from the edge of the clastic wedge that splits the coal seam and follows the upper bench of coal over and toward the center of the elastic wedge. The dominant elements of the vegetation were the lycopsid tree Paralycopodites brevifolius and several species of medullosan pteridosperms. This report confirms the ecotonal habitats of this vegetation. C1 Univ Illinois, Dept Plant Biol, Urbana, IL 61801 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20560 USA. RP Phillips, TL (reprint author), Univ Illinois, Dept Plant Biol, 505 S Goodwin Ave, Urbana, IL 61801 USA. RI DiMichele, William/K-4301-2012 NR 57 TC 16 Z9 17 U1 0 U2 4 PU SEPM-SOC SEDIMENTARY GEOLOGY PI TULSA PA 1731 E 71ST STREET, TULSA, OK 74136-5108 USA SN 0883-1351 J9 PALAIOS JI Palaios PD APR PY 1998 VL 13 IS 2 BP 113 EP 128 DI 10.2307/3515484 PG 16 WC Geology; Paleontology SC Geology; Paleontology GA ZG391 UT WOS:000072997100004 ER PT J AU Yan, ZC Ho, YK AF Yan, ZC Ho, YK TI P-wave autodissociating resonant states of positronium hydride SO PHYSICAL REVIEW A LA English DT Article AB P-wave autodissociating resonances in positronium-hydrogen scattering are calculated using the method of complex-coordinate rotation. The two lowest P-wave resonance energies and widths are determined by employing extensive Hylleraas-type wave functions. A comparison with published results is made. C1 Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, Cambridge, MA 02138 USA. Acad Sinica, Inst Atom & Mol Sci, Taipei, Taiwan. RP Yan, ZC (reprint author), Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Mol Phys, 60 Garden St, Cambridge, MA 02138 USA. RI Ho, Yew Kam/F-7912-2012; Yan, Zong-Chao/F-6668-2014 NR 21 TC 18 Z9 18 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 1998 VL 57 IS 4 BP R2270 EP R2273 DI 10.1103/PhysRevA.57.R2270 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZJ698 UT WOS:000073243700003 ER PT J AU Polhemus, DA AF Polhemus, DA TI Two new species of water striders (Heteroptera : Gerridae) from the Philippines SO PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON LA English DT Article DE Gerridae; aquatic insects; Philippines; Palawan; Mindanao AB Two new species of Gerridae are described from the Philippines: Ptilomera palawanensis from Palawan and Metrocoris zetteli from Mindanao. The descriptions are accompanied by a distribution map and figures of key characters. C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, Washington, DC 20560 USA. RP Polhemus, DA (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Entomol, MRC 105, Washington, DC 20560 USA. NR 5 TC 5 Z9 7 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 1998 VL 100 IS 2 BP 261 EP 268 PG 8 WC Entomology SC Entomology GA ZG951 UT WOS:000073056400010 ER PT J AU Heyman, JM AF Heyman, JM TI Lessons from the Mall - From courses to cruises, the Smithsonian has educational and cultural adventures for everyone SO SMITHSONIAN LA English DT Editorial Material C1 Smithsonian Inst, Washington, DC 20560 USA. RP Heyman, JM (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SMITHSONIAN ASSOCIATES PI WASHINGTON PA 900 JEFFERSON DRIVE, WASHINGTON, DC 20560 USA SN 0037-7333 J9 SMITHSONIAN JI Smithsonian PD APR PY 1998 VL 29 IS 1 BP 12 EP 12 PG 1 WC Humanities, Multidisciplinary SC Arts & Humanities - Other Topics GA ZE441 UT WOS:000072792900001 ER PT J AU Fortunato, H Penchaszadeh, PE Miloslavich, P AF Fortunato, H Penchaszadeh, PE Miloslavich, P TI Observations on the reproduction of Bifurcium bicanaliferum (Sowerby, 1832) (Gastropoda : Columbellidae : Strombina-group) from the Pacific Coast of Panama SO VELIGER LA English DT Article C1 Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archeol, Balboa, Panama. CONICET, Museo Argentino Ciencias Nat, Buenos Aires, DF, Argentina. Univ Simon Bolivar, INTECMAR, Caracas 1080, Venezuela. Univ Simon Bolivar, Dept Estudios Ambientales, Caracas 1080, Venezuela. RP Fortunato, H (reprint author), Smithsonian Trop Res Inst, Ctr Trop Paleoecol & Archeol, Apartado 2072, Balboa, Panama. NR 6 TC 2 Z9 3 U1 0 U2 0 PU CALIF MALACOZOOLOGICAL SOC INC PI SANTA BARBARA PA SANTA BARBARA MUSEUM NATURAL HISTORY, 2559 PUESTA DEL SOL RD, SANTA BARBARA, CA 93105 USA SN 0042-3211 J9 VELIGER JI Veliger PD APR 1 PY 1998 VL 41 IS 2 BP 208 EP 211 PG 4 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA ZH024 UT WOS:000073064500011 ER PT J AU Viola, HJ AF Viola, HJ TI 'Lewis and Clark, the journey of the corps of discovery' SO WILLIAM AND MARY QUARTERLY LA English DT TV Review, Radio Review C1 Smithsonian Inst, Washington, DC 20560 USA. RP Viola, HJ (reprint author), Smithsonian Inst, Washington, DC 20560 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU INST EARLY AMER HIST CULT PI WILLIAMSBURG PA BOX 220, WILLIAMSBURG, VA 23187 USA SN 0043-5597 J9 WILLIAM MARY QUART JI William Mary Q. PD APR PY 1998 VL 55 IS 2 BP 334 EP 336 DI 10.2307/2674403 PG 3 WC History SC History GA ZD833 UT WOS:000072729000023 ER PT J AU Wernicke, B Davis, JL Bennett, RA Elosegui, P Abolins, MJ Brady, RJ House, MA Niemi, NA Snow, JK AF Wernicke, B Davis, JL Bennett, RA Elosegui, P Abolins, MJ Brady, RJ House, MA Niemi, NA Snow, JK TI Anomalous strain accumulation in the Yucca Mountain Area, Nevada SO SCIENCE LA English DT Article ID LITTLE-SKULL-MOUNTAIN; GREAT-BASIN PROVINCE; SOUTHERN NEVADA; SLIP RATES; CONSTRAINTS; EARTHQUAKE; VOLCANISM; COMPLEX; GEODESY; REGION AB Global Positioning System (GPS) surveys from 1991 to 1997 near Yucca Mountain, Nevada, indicate west-northwest crustal elongation at a rate of 1.7 +/- 0.3 millimeters per year (1 sigma) over 34 kilometers, or 50 +/- 9 nanostrain per year. Global Positioning System and trilateration surveys from 1983 to 1997 on a 14-kilometer baseline across the proposed repository site for high-level radioactive waste indicate that the crust extended by 0.7 to 0.9 +/- 0.2 millimeter per year (50 to 64 +/- 14 nanostrain per year), depending on the coseismic effect of the M-s 5.4 1992 Little Skull Mountain earthquake. These strain rates are at least an order of magnitude higher than would be predicted from the Quaternary volcanic and tectonic history of the area. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Wernicke, B (reprint author), CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RI Davis, James/D-8766-2013; OI Davis, James/0000-0003-3057-477X; Niemi, Nathan/0000-0002-3380-3024 NR 35 TC 20 Z9 20 U1 1 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 MAR 27 PY 1998 VL 279 IS 5359 BP 2096 EP 2100 DI 10.1126/science.279.5359.2096 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZE274 UT WOS:000072775600044 ER PT J AU Losos, JB Jackman, TR Larson, A de Queiroz, K Rodriguez-Schettino, L AF Losos, JB Jackman, TR Larson, A de Queiroz, K Rodriguez-Schettino, L TI Contingency and determinism in replicated adaptive radiations of island lizards SO SCIENCE LA English DT Article ID ANOLIS LIZARDS; EVOLUTION AB The vagaries of history lead to the prediction that repeated instances of evolutionary diversification will lead to disparate outcomes even if starting conditions are similar. We tested this proposition by examining the evolutionary radiation of Anolis lizards on the four islands of the Greater Antilles. Morphometric analyses indicate that the same set of habitat specialists, termed ecomorphs, occurs on all four islands. Although these similar assemblages could result from a single evolutionary origin of each ecomorph, followed by dispersal or vicariance, phylogenetic analysis indicates that the ecomorphs originated independently on each island. Thus, adaptive radiation in similar environments can overcome historical contingencies to produce strikingly similar evolutionary outcomes. C1 Washington Univ, Dept Biol, St Louis, MO 63130 USA. Smithsonian Inst, Natl Museum Nat Hist, Div Amphibians & Reptiles, Washington, DC 20560 USA. CITMA, Inst Ecol & Sistemat, La Habana 10800, Cuba. RP Losos, JB (reprint author), Washington Univ, Dept Biol, Campus Box 1137, St Louis, MO 63130 USA. OI Jackman, Todd/0000-0002-5391-8136 NR 31 TC 623 Z9 635 U1 20 U2 153 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 27 PY 1998 VL 279 IS 5359 BP 2115 EP 2118 DI 10.1126/science.279.5359.2115 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZE274 UT WOS:000072775600050 ER PT J AU Fabian, AC Iwasawa, K Celotti, A Brandt, WN McMahon, RG Hook, IM AF Fabian, AC Iwasawa, K Celotti, A Brandt, WN McMahon, RG Hook, IM TI The ASCA spectrum of the z=4.72 blazar GB 1428+4217 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Letter DE quasars, individual, GB 1428+4217; X-rays, galaxies AB The X-ray-luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2 x 10(-12) erg cm(-2)s(-1). We report here on the intrinsic 4 - 57 keV X-ray spectrum, which is very flat (photon index 1.29). We find no evidence for flux variability within the ASCA data set or between it and ROSAT data. We show that the overall spectral energy distribution of GB 1428+4217 is similar to that of lower redshift MeV blazars, and present models that fit the available data. The Doppler beaming factor is likely to be at least 8. We speculate on the number density of such high-redshift blazars, which must contain rapidly formed massive black holes. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. SISSA, I-34014 Trieste, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. European So Observ, D-85748 Garching, Germany. RP Fabian, AC (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. RI Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 19 TC 26 Z9 26 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 MAR 21 PY 1998 VL 295 IS 1 BP L25 EP L28 DI 10.1046/j.1365-8711.1998.29511483.x PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZF497 UT WOS:000072903400006 ER PT J AU Barth, AJ Ho, LC Filippenko, AV Sargent, WLW AF Barth, AJ Ho, LC Filippenko, AV Sargent, WLW TI A search for ultraviolet emission from LINERs SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; galaxies, nuclei; ultraviolet, galaxies ID ACTIVE GALACTIC NUCLEI; SEYFERT-GALAXIES; X-RAY; STARBURST; NGC-1097 AB We have obtained Hubble Space Telescope Wide Field and Planetary Camera 2 ultraviolet (UV) 2200 Angstrom and optical V-band images of 20 low-luminosity active galactic nuclei, most of which are spectroscopically classified as LINERs, in order to search for a possible photoionizing continuum. Six (30%) of the galaxies are detected in the UV. Two of the detected galaxies (NGC 3642 and NGC 4203) have compact, unresolved nuclear UV sources, while the remaining four UV sources (in NGC 4569, NGC 5005, NGC 6500, and NGC 7743) are spatially extended. Combining our data set with the earlier sample of Maoz et al., we find that the probability of detection of a nuclear UV source is greatest for galaxies having low internal reddening and low inclination, and we conclude that dust obscuration is the dominant factor determining whether or not a UV source is detected. Large emission-line equivalent widths and the presence of broad-line emission also increase the likelihood of detection of nuclear UV emission. Our results suggest that the majority of LINERs harbor obscured nuclear UV sources, which may be either accretion-powered active nuclei or young star clusters. Under the assumption that the compact UV sources in NGC 3642 and NGC 4203 have nonstellar spectra of slope f(v) proportional to v(-1) extending into the extreme ultraviolet, the extrapolated ionizing fluxes are sufficiently strong to photoionize the narrow-line regions of these objects. The V-band images of many galaxies in our sample reveal remarkably strong dust lanes that may be responsible for obscuring some UV sources. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. RP Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. NR 49 TC 76 Z9 77 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 MAR 20 PY 1998 VL 496 IS 1 BP 133 EP + DI 10.1086/305379 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZE341 UT WOS:000072782900011 ER PT J AU Drake, JJ AF Drake, JJ TI Excess helium as an explanation for metal deficiency in coronal plasma? SO ASTROPHYSICAL JOURNAL LA English DT Article DE X-rays, galaxies; X-rays, stars ID SOLAR-WIND; ABUNDANCE AB We suggest an alternative explanation for the apparently low metal abundances observed in some very active late-type stellar coronae: that the He abundance in these coronae is enhanced, causing lower line-to-continuum ratios. The dependence of the total free-free Gaunt factor on the square of the nuclear charge means that He can begin to dominate the EUV and X-ray thermal continua of a hot plasma with only a doubling of the abundance of He2+ nuclei relative to HI nuclei. Using model continua, we calculate the relation between He abundance and apparent metal deficiency. We suggest that He might be selectively enhanced by preferential mechanisms for retention of He nuclei in the corona or by diffusion processes, as recent sophisticated calculations indicated might be the case under certain coronal conditions. While it might seem unlikely that He nuclei could be enhanced in the hot gas phase of elliptical galaxies, until the possible presence of small-scale structure and spatial inhomogeneitiess in their interstellar media are better understood, diffusion and other element fractionation processes should perhaps not be ruled out entirely in the context of trying to understand the puzzlingly low metal abundances found from X-ray studies of elliptical galaxies. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Drake, JJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 32 TC 17 Z9 17 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 1998 VL 496 IS 1 BP L33 EP L37 DI 10.1086/311235 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZE343 UT WOS:000072783100009 ER PT J AU Tucker, W Blanco, P Rappoport, S David, L Fabricant, D Falco, EE Forman, W Dressler, A Ramella, M AF Tucker, W Blanco, P Rappoport, S David, L Fabricant, D Falco, EE Forman, W Dressler, A Ramella, M TI 1E 0657-56: A contender for the hottest known cluster of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, individual (1E 0657-56); intergalactic medium large-scale structure of universe; X-rays, galaxies ID RICH CLUSTERS; TEMPERATURE FUNCTION; EVOLUTION; ABUNDANCE; GAS AB We identify the extended Einstein LPC X-ray source 1E 0657-56 with a previously unknown cluster of galaxies at a redshift of z = 0.296. Optical CCD images show the presence of a gravitational are in this cluster, and galaxy spectra yield a cluster velocity dispersion of 1213(-191)(+352) km s(-1). X-ray data obtained with the ROSAT HRI and ASCA indicate that 1E 0657-56 is a highly luminous cluster in which a merger of subclusters may be occurring. The temperature of the hot gas in 1E 0657-56 is kT = 17.4 +/- 2.5 keV, which makes it an unusually hot cluster, with important cosmological implications. C1 Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Osservatorio Astron Trieste, I-34131 Trieste, Italy. RP Tucker, W (reprint author), Univ Calif San Diego, Ctr Astrophys & Space Sci, 9500 Gilman Dr,Code 0111, La Jolla, CA 92093 USA. OI Ramella, Massimo/0000-0001-5446-4749; Forman, William/0000-0002-9478-1682 NR 32 TC 71 Z9 71 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 1998 VL 496 IS 1 BP L5 EP L8 DI 10.1086/311234 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZE343 UT WOS:000072783100002 ER PT J AU Newburg, DS Warren, CD Chaturvedi, P Newburg, AR Oftedal, OT Ye, S Tilden, CD AF Newburg, DS Warren, CD Chaturvedi, P Newburg, AR Oftedal, OT Ye, S Tilden, CD TI Differences in milk oligosaccharides between species. SO FASEB JOURNAL LA English DT Meeting Abstract C1 Shriver Ctr, Waltham, MA 02254 USA. Smithsonian Inst, Natl Zool Pk, Washington, DC 20008 USA. Boston Univ, Boston, MA 02118 USA. Univ Kansas, Lawrence, KS 66044 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR 17 PY 1998 VL 12 IS 4 SU S MA 1176 BP A202 EP A202 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 121HC UT WOS:000076006401178 ER PT J AU Hu, W Seljak, U White, M Zaldarriaga, M AF Hu, W Seljak, U White, M Zaldarriaga, M TI Complete treatment of CMB anisotropies in a FRW universe SO PHYSICAL REVIEW D LA English DT Article ID RADIATION; MATTER AB We generalize the total angular momentum method for computing cosmic microwave background anisotropies to Friedmann-Robertson-Walker (FRW) spaces with arbitrary geometries. This unifies the treatment of temperature and polarization anisotropies generated by scalar, vector and tensor perturbations of the fluid, seed, or a scalar field, in a universe with constant comoving curvature. The resulting formalism generalizes and simplifies the calculation of anisotropies and, in its integral form, allows for a fast calculation of model predictions in linear theory for any FRW metric. C1 Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. RP Inst Adv Study, Sch Nat Sci, Olden Lane, Princeton, NJ 08540 USA. RI White, Martin/I-3880-2015 OI White, Martin/0000-0001-9912-5070 NR 24 TC 133 Z9 133 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD MAR 15 PY 1998 VL 57 IS 6 BP 3290 EP 3301 DI 10.1103/PhysRevD.57.3290 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZC753 UT WOS:000072613900011 ER PT J AU Jamieson, MJ Dalgarno, A AF Jamieson, MJ Dalgarno, A TI How a change in the interaction potential affects the s-wave scattering length SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID ATOMIC-HYDROGEN; PHOTOASSOCIATIVE SPECTROSCOPY; FREQUENCY-SHIFT; MOLECULE; STATES; CURVES; VAPOR; HE AB The two-potential formula is used to find the change in the s-wave scattering length of a pair of colliding particles induced by a change in their interaction potential. It is illustrated by a calculation of the scattering length of hydrogen atoms interacting through the X (1) Sigma(g)(+) molecular state. The b (3) Sigma(u)(+) scattering length is also calculated with a recent potential. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Glasgow, Dept Comp Sci, Glasgow G12 8QQ, Lanark, Scotland. RP Jamieson, MJ (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 33 TC 23 Z9 23 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAR 14 PY 1998 VL 31 IS 5 BP L219 EP L222 DI 10.1088/0953-4075/31/5/002 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZD681 UT WOS:000072711700002 ER PT J AU Smith, BD AF Smith, BD TI Research: Origins of agriculture - Between foraging and farming SO SCIENCE LA English DT Article C1 Smithsonian Inst, Natl Museum Nat Hist, Dept Anthropol, Washington, DC 20560 USA. RP Smith, BD (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Anthropol, Washington, DC 20560 USA. NR 7 TC 15 Z9 15 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 MAR 13 PY 1998 VL 279 IS 5357 BP 1651 EP 1652 DI 10.1126/science.279.5357.1651 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZB612 UT WOS:000072490000035 ER PT J AU Hardcastle, MJ Birkinshaw, M Worrall, DM AF Hardcastle, MJ Birkinshaw, M Worrall, DM TI Magnetic field strengths in the hotspots of 3C 33 and 111 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE magnetic fields; radiation mechanisms, non-thermal; galaxies, individual, 3C 33; galaxies, individual, 3C 111; X-rays, galaxies ID X-RAY OBSERVATIONS; RADIO HOT SPOTS; COMPLETE SAMPLE; CYGNUS-A; GALAXIES; EMISSION; SPECTRA; LOBE; JET; AGN AB We report on ROSAT HRI observations of the nearby powerful radio galaxies 3C 33 and 111, which both have detected optical hotspots. We find nuclear X-ray sources in both objects, but no X-ray emission from the hotspots. This confirms the presence of a high-energy cut-off in the spectrum of synchrotron-emitting electrons. Since these electrons necessarily scatter the synchrotron photons by the inverse Compton process, our upper limits on the X-ray fluxes of the hotspots allow us to set lower limits of a few nanotesla on their magnetic flux density, close to or greater than the fields implied by equipartition of energy between radiating particles and magnetic field. C1 Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Hardcastle, MJ (reprint author), Univ Bristol, Dept Phys, Tyndall Ave, Bristol BS8 1TL, Avon, England. RI Hardcastle, Martin/E-2264-2012 OI Hardcastle, Martin/0000-0003-4223-1117 NR 38 TC 57 Z9 57 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 MAR 11 PY 1998 VL 294 IS 4 BP 615 EP 621 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZE043 UT WOS:000072751600009 ER PT J AU Perrin, G du Foresto, VC Ridgway, ST Mariotti, JM Traub, WA Carleton, NP Lacasse, MG AF Perrin, G du Foresto, VC Ridgway, ST Mariotti, JM Traub, WA Carleton, NP Lacasse, MG TI Extension of the effective temperature scale of giants to types later than M6 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE techniques : interferometric; stars : atmospheres; fundamental parameters; late-type; infrared : stars ID SEMIREGULAR VARIABLES; IOTA INTERFEROMETER; ANGULAR DIAMETERS; MU-M; STARS; JHKL'M-PHOTOMETRY; COOLER; SRA AB Effective temperatures for nine giant stars are derived from recent diameter determinations at 2.2 mu m with the FLUOR beam combiner on the IOTA interferometer. A good overlap with previous studies for stars earlier than M6 is verified. The present paper extends the temperature scale of giant stars based on direct measurements to types between M6 and M8. C1 Observ Paris, DESPA, F-92195 Meudon, France. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Observ Paris, DESPA, F-92195 Meudon, France. EM perrin@hplyot.obspm.fr NR 30 TC 139 Z9 139 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 10 PY 1998 VL 331 IS 2 BP 619 EP 626 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZB894 UT WOS:000072518700030 ER PT J AU Kolatt, T AF Kolatt, T TI Determination of the primordial magnetic field power spectrum by Faraday rotation correlations SO ASTROPHYSICAL JOURNAL LA English DT Article DE intergalactic medium; large-scale structure of universe; magnetic fields; polarization ID ANGULAR-CORRELATION FUNCTION; EXTRAGALACTIC RADIO-SOURCES; SMALL-SCALE VARIATIONS; ENERGY COSMIC-RAYS; SKY SURVEY; GALAXIES; QUASARS; ORIGIN; INFLATION; UNIVERSE AB This paper introduces the formalism which connects between rotation measure (RM) measurements for extragalactic sources and the cosmological magnetic field power spectrum. It is shown that the amplitude and shape of the cosmological magnetic field power spectrum can be constrained by using a few hundred radio sources, for which Faraday RMs are available. This constraint is of the form B-rms less than or similar to 1 x (26 x 10(-7) cm(-3)/(n) over bar(b)]) h nG on similar to 10-50 h(-1) Mpc scales, with (n) over bar(b) the average baryon density and h the Hubble parameter in units of 100 km s(-1) Mpc The constraint is superior to and supersedes any other constraint that comes from either cosmic microwave background (CMB) fluctuations, baryonic nucleosynthesis, or the first two multipoles of the magnetic field expansion. The most adequate method for the constraint calculation uses the Bayesian approach to the maximum likelihood function. I demonstrate the ability to detect such magnetic fields by constructing simulations of the field and mimicking observations. This procedure also provides error estimates for the derived quantities. The two main noise contributions due to the Galactic RM and the internal RM are treated in a statistical way following an evaluation of their distribution. For a range of magnetic field power spectra with power indices -1 less than or equal to n less than or equal to 1 in a flat cosmology (Omega(m) = 1) we estimate the signal-to-noise ratio, Q, for limits on the magnetic field B-rms on a similar to 50 h(-1) Mpc scale. Employing one patch of a few square degrees on the sky with source number density n(src), an approximate estimate yields Q similar or equal to 3(B-rms/1 nG)(n(src)/50 deg(-2))(2.6 x 10(-7) cm(-3)/(n) over bar(b)) h. An all-sky coverage, with a much sparser but carefully tailored sample of similar to 500 sources, yields Q similar or equal to 1 with the same scaling. An ideal combination of small densely sampled patches and sparse all-sky coverage yields Q similar or equal to 3 with better constraints for the power index. All of these estimates are corroborated by the simulations. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM tsafrir@physics.ucsc.edu NR 67 TC 35 Z9 35 U1 0 U2 0 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 MAR 10 PY 1998 VL 495 IS 2 BP 564 EP 579 DI 10.1086/305310 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZD699 UT WOS:000072714200007 ER PT J AU Loeb, A Perna, R AF Loeb, A Perna, R TI Microlensing of gamma-ray burst afterglows SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology, theory; gamma rays, bursts; gravitational lensing AB The afterglow of a cosmological gamma-ray burst (GRB) should appear on the sky as a narrow emission ring of radius similar to 3 x 10(16) cm (t/day)(5/8) that expands faster than light. After a day, the ring radius is comparable to the Einstein radius of a solar mass lens at a cosmological distance. Thus, microlensing by an intervening star can significantly modify the light curve and polarization signal from a GRB afterglow. We show that the achromatic amplification signal of the afterglow flux can be used to determine the impact parameter and expansion rate of the source in units of the Einstein radius of the lens, and we probe the superluminal nature of the expansion. If the synchrotron emission from the afterglow photosphere originates from a set of coherent magnetic field patches, microlensing would induce polarization variability as a result of the transient magnification of the patches behind the lens. The microlensing interpretation of the flux and polarization data can be confirmed by a parallax experiment that would probe the amplification peak at different times. The fraction of microlensed afterglows can be used to calibrate the density parameter of stellar-mass objects in the universe. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Loeb, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 30 TC 52 Z9 52 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1998 VL 495 IS 2 BP 597 EP 603 DI 10.1086/305337 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZD699 UT WOS:000072714200009 ER PT J AU Trotter, AS Greenhill, LJ Moran, JM Reid, MJ Irwin, JA Lo, KY AF Trotter, AS Greenhill, LJ Moran, JM Reid, MJ Irwin, JA Lo, KY TI Water maser emission and the parsec-scale jet in NGC 3079 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; galaxies, individual (NGC 3079); galaxies, jets; galaxies, nuclei; masers ID STAR-FORMING REGIONS; H2O MASERS; GALAXY NGC-3079; ACTIVE GALAXIES; SPIRAL GALAXIES; GALACTIC NUCLEI; RADIO-SOURCES; VAPOR MASER; OUTFLOW; SHOCKS AB We have conducted VLBI observations at subparsec resolution of water maser and radio continuum emission in the nucleus of the nearby active galaxy NGC 3079. The 22 GHz maser emission arises in compact (similar to 0.01 pc at a distance of 16 Mpc) clumps, distributed over similar to 2 pc along an axis that is approximately aligned with the major axis of the galactic disk. The Doppler velocities of the water maser clumps are consistent with their lying in the inner parsec of a molecular disk with a binding mass similar to 10(6) M-circle dot, rotating in the same sense as the edge-on kiloparsec-scale molecular disk observed in CO emission. However, the velocity held has a significant nonrotational component, which may indicate supersonic turbulence in the disk. This distribution is markedly different from that of water masers in NGC 4258, which trace a nearly perfectly Keplerian rotating disk with a binding mass of 3.5 x 10(7) M-circle dot. The 22 GHz radio continuum emission in NGC 3079 is dominated by a compact (<0.1 pc) source that is offset 0.5 pc to the west of the brightest maser feature. No bright maser emission is coincident with a detected compact continuum source. This suggests that the large apparent luminosity of the maser is not caused by beamed amplification of high brightness temperature continuum emission. At 8 and 5 GHz, we confirm the presence of two compact continuum sources with a projected separation of 1.5 pc. Both have inverted spectra between 5 and 8 GHz and steep spectra between 8 and 22 GHz. NGC 3079 may be a nearby, low-luminosity example of the class of compact symmetric gigahertz-peaked spectrum radio sources. We detected a third continuum component that lies along the same axis as the other two, strongly suggesting that this galaxy possesses a nuclear jet. Faint maser emission was detected near this axis, which may indicate a second population of masers associated with the jet. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Queens Univ, Kingston, ON K7L 3N6, Canada. Univ Illinois, Urbana, IL 61801 USA. RP Trotter, AS (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 55 TC 87 Z9 88 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1998 VL 495 IS 2 BP 740 EP 748 DI 10.1086/305335 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZD699 UT WOS:000072714200022 ER PT J AU Schenk, PM Bulmer, MH AF Schenk, PM Bulmer, MH TI Origin of mountains on lo by thrust faulting and large-scale mass movements SO SCIENCE LA English DT Article ID LANDSLIDE AB Voyager stereoimages of Euboea Montes, lo, indicate that this mountain formed when a large crustal block was uplifted 10.5 kilometers and tilted by approximately 6 degrees. Uplift triggered a massive slope failure on the northwest flank, forming one of the largest debris aprons in the solar system. This slope failure probably involved relatively unconsolidated layers totaling approximately 2 kilometers in thickness, overlying a rigid crust (or lithosphere) at least 11 kilometers thick. Mountain formation on lo may involve localized deep-rooted thrust faulting and block rotation, due to compression at depth induced during vertical recycling of lo's crust. C1 Lunar & Planetary Inst, Houston, TX 77055 USA. Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Sci, Washington, DC 20560 USA. RP Schenk, PM (reprint author), Lunar & Planetary Inst, 3303 NASA Rd 1, Houston, TX 77055 USA. EM schenk@lpi3.jsc.nasa.gov NR 35 TC 65 Z9 65 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 MAR 6 PY 1998 VL 279 IS 5356 BP 1514 EP 1517 DI 10.1126/science.279.5356.1514 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZA527 UT WOS:000072372900058 ER EF