1,264 research outputs found
Review of geographical stocks of tropical dolphins (Stenella spp. and Delphinus delphis) in the eastern Pacific
Information on geographical variation is reviewed for Stenella attenuata, S. longirostris, S. coeruleoalba, and
Delphinus delphis in the eastern tropical Pacific, and boundaries for potential management units are proposed.
National Marine Fisheries Service and Inter-American Tropical Tuna Commission sighting records made from 1979 to 1983 which were outside boundaries used in a 1979 assessment were examined for validity. Tagging returns and morphological data were also analyzed. Several stock ranges are expanded or combined. Three management units are proposed for S. attenuata: the coastal, northern offshore, and southern offshore spoiled dolphins. Four management units are proposed for S. longirostris: the Costa Rican, eastern, northern whitebelly, and southern whitebelly spinner dolphins. Two provisional management units are proposed for S. coeruleoalba: the northern and southern striped dolphins. Five management units (two of which are provisional) are proposed for D. delphis: the Baja neritic, northern, central, southern, and Guerrero common dolphins. Division into management units was based on morphological stock differences and distributional breaks. (PDF file contains 34 pages.
Evidence That Hydra I is a Tidally Disrupting Milky Way Dwarf Galaxy
The Eastern Banded Structure (EBS) and Hydra I halo overdensities are very nearby (d ~ 10 kpc) objects discovered in Sloan Digital Sky Survey (SDSS) data. Previous studies of the region have shown that EBS and Hydra I are spatially coincident, cold structures at the same distance, suggesting that Hydra I may be the EBS's progenitor. We combine new wide-field Dark Energy Camera (DECam) imaging and MMT/Hectochelle spectroscopic observations of Hydra I with SDSS archival spectroscopic observations to quantify Hydra I's present-day chemodynamical properties, and to infer whether it originated as a star cluster or dwarf galaxy. While previous work using shallow SDSS imaging assumed a standard old, metal-poor stellar population, our deeper DECam imaging reveals that Hydra I has a thin, well-defined main sequence turnoff of intermediate age (~5–6 Gyr) and metallicity ([Fe/H] = −0.9 dex). We measure statistically significant spreads in both the iron and alpha-element abundances of σ_[(Fe)/H}= 0.13 ± 0.02 dex and σ_[ɑ/Fe] = 0.09 ± 0.03 dex, respectively, and place upper limits on both the rotation and its proper motion. Hydra I's intermediate age and [Fe/H]—as well as its low [α/Fe], apparent [Fe/H] spread, and present-day low luminosity—suggest that its progenitor was a dwarf galaxy, which has subsequently lost more than 99.99% of its stellar mass
Signatures of Tidal Disruption in Ultra-Faint Dwarf Galaxies: A Combined HST, Gaia, and MMT/Hectochelle Study of Leo V
The ultra-faint dwarf galaxy Leo V has shown both photometric overdensities
and kinematic members at large radii, along with a tentative kinematic
gradient, suggesting that it may have undergone a close encounter with the
Milky Way. We investigate these signs of disruption through a combination of i)
high-precision photometry obtained with the Hubble Space Telescope (HST), ii)
two epochs of stellar spectra obtained with the Hectochelle Spectrograph on the
MMT, and iii) measurements from the Gaia mission. Using the HST data, we
examine one of the reported stream-like overdensities at large radii, and
conclude that it is not a true stellar stream, but instead a clump of
foreground stars and background galaxies. Our spectroscopic analysis shows that
one known member star is likely a binary, and challenges the membership status
of three others, including two distant candidates that had formerly provided
evidence for overall stellar mass loss. We also find evidence that the proposed
kinematic gradient across Leo V might be due to small number statistics. We
update the systemic proper motion of Leo V, finding , mas yr, which is
consistent with its reported orbit that did not put Leo V at risk of being
disturbed by the Milky Way. These findings remove most of the observational
clues that suggested Leo V was disrupting, however, we also find new plausible
member stars, two of which are located >5 half-light radii from the main body.
These stars require further investigation. Therefore, the nature of Leo V still
remains an open question.Comment: Higher resolution figures are available upon request. Submitted to
the Ap
Pylons in the back yard: local planning and perceived risks to health
Health fears arising from the presence of high-voltage power lines in residential areas have received recent attention in spatial planning. A study of stances taken by planning authorities in England and Wales shows their willingness to give expression to the concerns of local communities through precautionary measures, and the difficulties encountered in the face of official statements and industry opposition. These attempts to embody local feeling in patterns of development are illustrative of the increasing prevalence of a sense of risk in contemporary society. The spatial patterns of risk are also revealed, which owe much to the presence and distribution of industrial infrastructure in the landscape and to the associated contested use of land.</p
VAST: An ASKAP Survey for Variables and Slow Transients
The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an
unprecedented opportunity to investigate the transient sky at radio
wavelengths. In this paper we present VAST, an ASKAP survey for Variables and
Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP
to enable the discovery and investigation of variable and transient phenomena
from the local to the cosmological, including flare stars, intermittent
pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar
scintillation, radio supernovae and orphan afterglows of gamma ray bursts. In
addition, it will allow us to probe unexplored regions of parameter space where
new classes of transient sources may be detected. In this paper we review the
known radio transient and variable populations and the current results from
blind radio surveys. We outline a comprehensive program based on a multi-tiered
survey strategy to characterise the radio transient sky through detection and
monitoring of transient and variable sources on the ASKAP imaging timescales of
five seconds and greater. We also present an analysis of the expected source
populations that we will be able to detect with VAST.Comment: 29 pages, 8 figures. Submitted for publication in Pub. Astron. Soc.
Australi
The Hubble Space Telescope Wide Field Camera 3 Early Release Science data: Panchromatic Faint Object Counts for 0.2-2 microns wavelength
We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early
Release Science (ERS) observations in the Great Observatories Origins Deep
Survey (GOODS) South field. The new WFC3 ERS data provide calibrated, drizzled
mosaics in the UV filters F225W, F275W, and F336W, as well as in the near-IR
filters F098M (Ys), F125W (J), and F160W (H) with 1-2 HST orbits per filter.
Together with the existing HST Advanced Camera for Surveys (ACS) GOODS-South
mosaics in the BViz filters, these panchromatic 10-band ERS data cover 40-50
square arcmin at 0.2-1.7 {\mu}m in wavelength at 0.07-0.15" FWHM resolution and
0.090" Multidrizzled pixels to depths of AB\simeq 26.0-27.0 mag (5-{\sigma})
for point sources, and AB\simeq 25.5-26.5 mag for compact galaxies.
In this paper, we describe: a) the scientific rationale, and the data taking
plus reduction procedures of the panchromatic 10-band ERS mosaics; b) the
procedure of generating object catalogs across the 10 different ERS filters,
and the specific star-galaxy separation techniques used; and c) the reliability
and completeness of the object catalogs from the WFC3 ERS mosaics. The
excellent 0.07-0.15" FWHM resolution of HST/WFC3 and ACS makes star- galaxy
separation straightforward over a factor of 10 in wavelength to AB\simeq 25-26
mag from the UV to the near-IR, respectively.Comment: 51 pages, 71 figures Accepted to ApJS 2011.01.2
High Post-Capture Survival for Sharks, Rays and Chimaeras Discarded in the Main Shark Fishery of Australia?
Most sharks, rays and chimaeras (chondrichthyans) taken in commercial fisheries are discarded (i.e. returned to the ocean either dead or alive). Quantifying the post-capture survival (PCS) of discarded species is therefore essential for the improved management and conservation of this group. For all chondrichthyans taken in the main shark fishery of Australia, we quantified the immediate PCS of individuals reaching the deck of commercial shark gillnet fishing vessels and applied a risk-based method to semi-quantitatively determine delayed and total PCS. Estimates of immediate, delayed and total PCS were consistent, being very high for the most commonly discarded species (Port Jackson shark, Australian swellshark, and spikey dogfish) and low for the most important commercial species (gummy and school sharks). Increasing gillnet soak time or water temperature significantly decreased PCS. Chondrichthyans with bottom-dwelling habits had the highest PCS whereas those with pelagic habits had the lowest PCS. The risk-based approach can be easily implemented as a standard practice of on-board observing programs, providing a convenient first-step assessment of the PCS of all species taken in commercial fisheries
Chorioamnionitis: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data
Chorioamnionitis is a term encompassing a broad spectrum of
disease during pregnancy that is characterized by inflammation
and/or infection of intrauterine structures such as the placenta,
the chorion and amnion. The clinical presentation
of chorioamnionitis can vary based on clinical, microbiologic, and
histologic factors which interact and overlap to varying degrees
Angiosperm phylogeny: 17 genes, 640 taxa
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/1/ajb20704-sup-0010.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/2/ajb20704.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/3/ajb20704-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/4/ajb20704-sup-0016.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/5/ajb20704-sup-0017.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/6/ajb20704-sup-0021.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/7/ajb20704-sup-0003.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/8/ajb20704-sup-0002.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/9/ajb20704-sup-0011.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/10/ajb20704-sup-0019.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/11/ajb20704-sup-0015.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/12/ajb20704-sup-0006.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/13/ajb20704-sup-0020.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/14/ajb20704-sup-0013.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/15/ajb20704-sup-0004.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/16/ajb20704-sup-0012.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/17/ajb20704-sup-0005.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/18/ajb20704-sup-0018.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/19/ajb20704-sup-0009.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/20/ajb20704-sup-0014.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/21/ajb20704-sup-0007.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/22/ajb20704-sup-0008.pd
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