Ontogenetic changes in shape and growth rate during postnatal development in false killer whales (<i>Pseudorca crassidens</i>) vertebral column

Intraspecific variation in cetacean vertebral anatomy as a result of ageing, growth, and sexual dimorphism is poorly understood. Using 3D geometric morphometrics, we investigated allometric patterns, sexual dimorphism, and ontogenetic trajectories in the vertebral column of false killer whale (Pseudorca crassidens). Our data set includes thoracic, lumbar, and caudal vertebrae of 30 specimens, including neonates, juveniles, and adults of both sexes. Vertebral shape was significantly correlated with size within each region. Neonatal vertebral shape differed significantly from juveniles and adults, displaying ontogenetic shape change. Allometric and growth patterns of the vertebral regions, particularly of the lumbar region with the thoracic and caudal regions, differed significantly, which may influence the function and mobility patterns of the vertebral regions during different life stages. Using quantitative methods, we could not conclude that the Pseudorca vertebrae are sexually dimorphic. This study describes for the first time intraspecific vertebral patterns in a cetacean species across ontogenetic stages. Pseudorca individuals live in large pods and swim together, sharing the same swimming mode. The neonates have a more flexible column and swim less efficiently following their mothers to nurse

Test of the Running of αs\alpha_s in τ\tau Decays

The $\tau$ decay rate into hadrons of invariant mass smaller than $\sqrt{s_0}\gg\Lambda_{\rm QCD}$ can be calculated in QCD assuming global quark--hadron duality. It is shown that this assumption holds for $s_0>0.7$~GeV$^2$. From measurements of the hadronic mass distribution, the running coupling constant $\alpha_s(s_0)$ is extracted in the range 0.7~GeV$^2<s_0<m_\tau^2$. At $s_0=m_\tau^2$, the result is $\alpha_s(m_\tau^2)=0.329\pm 0.030$. The running of $\alpha_s$ is in good agreement with the QCD prediction.Comment: 9 pages, 3 figures appended; shortened version with new figures, to appear in Physical Review Letters (April 1996

Measurements of hydrogen cyanide (HCN) and acetylene (C2H2) from the Infrared Atmospheric Sounding Interferometer (IASI)

Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform InfraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values

Gamma-Ray Burst Sequences in Hardness Ratio-Peak Energy Plane

The narrowness of the distribution of the peak energy of $\nu F_{\nu}$ spectrum of gamma-ray bursts (GRBs) and the unification of GRB population are great puzzles yet to be solved. We investigate the two puzzles based on the global spectral behaviors of different GRB population in the $HR-E_{\rm{p}}$ plane (HR the spectral hardness ratio) with BATSE and HETE-2 observations. It is found that long GRBs and XRFs observed by HETE-2 seem to follow the same sequence in the $HR-E_{\rm{p}}$ plane, with the XRFs at the low end of this sequence. The long and short GRBs observed by BATSE follow significantly different sequences in the $HR-E_{\rm p}$ plane, with most of the short GRBs having a larger hardness ratio than the long GRBs at a given $E_{\rm{p}}$. These results indicate that the global spectral behaviors of the long GRB sample and the XRF sample are similar, while that of short GRBs is different. The short GRBs seem to be a unique subclass of GRBs, and they are not the higher energy extension of the long GRBs (abridged).Comment: 9 pages, 3 figure

The Minimal Supersymmetric Standard Model: Group Summary Report

CONTENTS: 1. Synopsis, 2. The MSSM Spectrum, 3. The Physical Parameters, 4. Higgs Boson Production and Decays, 5. SUSY Particle Production and Decays, 6. Experimental Bounds on SUSY Particle Masses, 7. References.Comment: 121 pages, latex + epsfig, graphicx, axodraw, Report of the MSSM working group for the Workshop "GDR-Supersym\'etrie",France. Rep. PM/98-4

The Structure of the Local Interstellar Medium. II. Observations of D I, C II, N I, O I, Al II, and Si II toward Stars within 100 parsecs

Moderate and high-resolution measurements (R ~ 40,000) of interstellar resonance lines of D I, C II, N I, O I, Al II, and Si II (light ions) are presented for all available observed targets located within 100 pc which also have high-resolution observations of interstellar Fe II or Mg II (heavy ions) lines. All spectra were obtained with the Goddard High Resolution Spectrograph or the Space Telescope Imaging Spectrograph instruments aboard the Hubble Space Telescope. Currently, there are 41 sightlines to targets within 100 pc with observations that include a heavy ion at high resolution and at least one light ion at moderate or high resolution. We present new measurements of light ions along 33 of these sightlines, and collect from the literature results for the remaining sightlines that have already been analyzed. We greatly increase the number of sightlines with useful LISM absorption line measurements of light ions by using knowledge of the kinematic structure along a line of sight obtained from high resolution observations of intrinsically narrow absorption lines, such as Fe II and Mg II. Because high resolution observations of heavy ions are critical for understanding the kinematic structure of local absorbers along the line of sight, we include 18 new measurements of Fe II and Mg II in an appendix. We present a statistical analysis of the LISM absorption measurements, which provides an overview of some physical characteristics of warm clouds in the LISM, including temperature and turbulent velocity. This complete collection and reduction of all available LISM absorption measurements provides an important database for studying the structure of nearby warm clouds, including ionization, abundances, and depletions.Comment: 50 pages, 21 figures; Accepted for publication in ApJ (vol. 602, February 20, 2004

On the nature of the Be star HR 7409 (7 Vul)

HR 7409 (7 Vul) is a newly identified Be star possibly part of the Gould Belt and is the massive component of a 69-day spectroscopic binary. The binary parameters and properties of the Be star measured using high-dispersion spectra obtained at Ondrejov Observatory and at Rozhen Observatory imply the presence of a low mass companion (~ 0.5-0.8 M_sun). If the pair is relatively young (<50-80 Myr), then the companion is a K V star, but, following another, older evolutionary scenario, the companion is a horizontal-branch star or possibly a white dwarf star. In the latter scenario, a past episode of mass transfer from an evolved star onto a less massive dwarf star would be responsible for the peculiar nature of the present-day, fast-rotating Be star.Comment: Accepted for publication in MNRA

The Primordial Binary Population - I: A near-infrared adaptive optics search for close visual companions to A star members of Scorpius OB2

We present the results of a near-infrared adaptive optics survey with the aim to detect close companions to Hipparcos members in the three subgroups of the nearby OB association Sco OB2: Upper Scorpius (US), Upper Centaurus Lupus (UCL) and Lower Centaurus Crux (LCC). We have targeted 199 A-type and late B-type stars in the Ks band, and a subset also in the J and H band. We find 151 stellar components other than the target stars. A brightness criterion is used to separate these components into 77 background stars and 74 candidate physical companion stars. Out of these 74 candidate companions, 41 have not been reported before (14 in US; 13 in UCL; 14 in LCC). Companion star masses range from 0.1 to 3 Msun. The mass ratio distribution follows f(q) = q^-0.33, which excludes random pairing. No close (rho < 3.75'') companion stars or background stars are found in the magnitude range 12 < Ks < 14. The lack of stars with these properties cannot be explained by low-number statistics, and may imply a lower limit on the companion mass of ~ 0.1 Msun. Close stellar components with Ks > 14 are observed. If these components are very low-mass companion stars, a gap in the companion mass distribution might be present. The small number of close low-mass companion stars could support the embryo-ejection formation scenario for brown dwarfs. Our findings are compared with and complementary to visual, spectroscopic, and astrometric data on binarity in Sco OB2. We find an overall companion star fraction of 0.52 in this association. This paper is the first step toward our goal to derive the primordial binary population in Sco OB2.Comment: 27 pages, to accepted by A&