13 research outputs found
Faint High Latitude Carbon Stars Discovered by the Sloan Digital Sky Survey: Methods and Initial Results
We report the discovery of 39 Faint High Latitude Carbon Stars (FHLCs) from
Sloan Digital Sky Survey commissioning data. The objects, each selected
photometrically and verified spectroscopically, range over 16.6 < r* < 20.0,
and show a diversity of temperatures as judged by both colors and NaD line
strengths. At the completion of the Sloan Survey, there will be many hundred
homogeneously selected and observed FHLCs in this sample. We present proper
motion measures for each object, indicating that the sample is a mixture of
extremely distant (>100 kpc) halo giant stars, useful for constraining halo
dynamics, plus members of the recently-recognized exotic class of very nearby
dwarf carbon (dC) stars. Motions, and thus dC classification, are inferred for
40-50 percent of the sample, depending on the level of statistical significance
invoked. The new list of dC stars presented here, although selected from only a
small fraction of the final SDSS, doubles the number of such objects found by
all previous methods. (Abstract abridged).Comment: Accepted for publication in The Astronomical Journal, Vol. 124, Sep.
2002, 40 pages, 7 figures, AASTeX v5.
New insights on the Draco dwarf spheroidal galaxy from SDSS: a larger radius and no tidal tails
We have investigated the spatial extent and structure of the Draco dwarf
spheroidal galaxy using deep wide-field multicolor CCD photometry from the
Sloan Digital Sky Survey (SDSS). Our study covers an area of 27 square degrees
around the center of the Draco dwarf. We show that the spatial distribution of
Draco's red giants, red horizontal branch stars and subgiants down to i=21.7
mag does not provide evidence for the existence of tidally induced tails or a
halo of unbound stars. The radial profile can be fit by King models as well as
by a generalized exponential. The core radius and the limiting (or tidal)
radius along the major axis are 7.7' and 40.1', respectively, making Draco 40%
larger than previously measured. Down to our magnitude limit tidal effects can
only exist at a level of 10^-3 of the central surface density of Draco or
below. The regular structure of Draco found from the new data argues against it
being a portion of an unbound tidal stream and lends support to the assumption
of dynamical equilibrium. We estimate Draco's total mass to be 2.2 - 3.5 times
10^7 solar masses. We obtain an overall mass-to-light ratio of 146+-42 or
92+-28 solar masses depending on the details of the mass and luminosity
estimates. In summary, our results strengthen the case for a strongly dark
matter dominated, bound stellar system. (Abstract strongly abridged).Comment: 30 pages, 11 figures (in part with degraded resolution). Accepted for
publication in the Astronomical Journa
Whole-Genome Sequencing Uncovers Two Loci for Coronary Artery Calcification and Identifies Arse as a Regulator of Vascular Calcification
Coronary artery calcification (CAC) is a measure of atherosclerosis and a well-established predictor of coronary artery disease (CAD) events. Here we describe a genome-wide association study (GWAS) of CAC in 22,400 participants from multiple ancestral groups. We confirmed associations with four known loci and identified two additional loci associated with CAC (ARSE and MMP16), with evidence of significant associations in replication analyses for both novel loci. Functional assays of ARSE and MMP16 in human vascular smooth muscle cells (VSMCs) demonstrate that ARSE is a promoter of VSMC calcification and VSMC phenotype switching from a contractile to a calcifying or osteogenic phenotype. Furthermore, we show that the association of variants near ARSE with reduced CAC is likely explained by reduced ARSE expression with the G allele of enhancer variant rs5982944. Our study highlights ARSE as an important contributor to atherosclerotic vascular calcification, and a potential drug target for vascular calcific disease
Accounting and Medicine: An Exploratory Investigation into Physicians’ Attitudes Toward the Use of Standard Cost-Accounting Methods in Medicine
diagnostic related groups (DRGs), evidence based best practices (EBBP), grounded theory methodology, health care ethics, physician practices,
Recommended from our members
Whole-genome sequencing uncovers two loci for coronary artery calcification and identifies ARSE as a regulator of vascular calcification.
Coronary artery calcification (CAC) is a measure of atherosclerosis and a well-established predictor of coronary artery disease (CAD) events. Here we describe a genome-wide association study (GWAS) of CAC in 22,400 participants from multiple ancestral groups. We confirmed associations with four known loci and identified two additional loci associated with CAC (ARSE and MMP16), with evidence of significant associations in replication analyses for both novel loci. Functional assays of ARSE and MMP16 in human vascular smooth muscle cells (VSMCs) demonstrate that ARSE is a promoter of VSMC calcification and VSMC phenotype switching from a contractile to a calcifying or osteogenic phenotype. Furthermore, we show that the association of variants near ARSE with reduced CAC is likely explained by reduced ARSE expression with the G allele of enhancer variant rs5982944. Our study highlights ARSE as an important contributor to atherosclerotic vascular calcification, and a potential drug target for vascular calcific disease