60 research outputs found
Karon Jacquelyn Edge and Penelope Ann Erion in a Joint Senior Recital
This is the program for the joint senior recital of soprano Karon Jacqulyn Edge and pianist Penelope Ann Erion. Ms. Edge was accompanied on the piano by Mrs. Cindy Fuller. This recital took place on March 9, 1995, in the McBeth Recital Hall in the Mabee Fine Arts Center
A Collision of Subclusters in Abell 754
We present direct evidence of a collision of subclusters in the galaxy
cluster Abell 754. Our comparison of new optical data and archival ROSAT PSPC
X-ray data reveal three collision signatures predicted by n-body/hydrodynamical
simulations of hierarchical cluster evolution. First, there is strong evidence
of a non-hydrostatic process; neither of the two major clumps in the galaxy
distribution lies on the off-center peak of the X-ray emission from the
intracluster gas. Second, the peak of the X-ray emission is elongated
perpendicular to the collision axis defined by the centroids of the two galaxy
clumps. Third, there is evidence of compression-heated gas; one of A754's two
X-ray temperature components (Henry & Briel 1995) is among the hottest observed
in any cluster and hotter than that inferred from the velocity dispersion of
the associated galaxy clump. These signatures are consistent with the
qualitative features of simulations (Evrard 1990a,b) in which two subclusters
have collided in the plane of the sky during roughly the last Gyr. The
detection of such collisions is crucial for understanding both the dynamics of
individual clusters and the underlying cosmology. First, for systems like A754,
estimating the cluster X-ray mass from assumptions of hydrostatic equilibrium
and isothermality is incorrect and may produce the discrepancies sometimes
found between X-ray masses and those derived from gravitational lens models
(Babul & Miralda-Escude 1994). Second, the fraction of nearby clusters in which
subclusters have collided in the last Gyr is especially sensitive to the mean
mass density parameter Omega_0 (cf. Richstone et al. 1992; Evrard et al. 1993;
Lacey & Cole 1993). With a large, well-defined cluster sample, it will be
possible to place a new and powerful constraint on cosmological models.Comment: 4 pages + 1 color figure (Postscript). Accepted for Publication in
ApJ Letter
The Properties of Poor Groups of Galaxies: II. X-ray and Optical Comparisons
We use ROSAT PSPC data to study the X-ray properties of a sample of twelve
poor groups that have extensive membership information (Zabludoff and Mulchaey
1997; Paper I). Diffuse X-ray emission is detected in nine of these groups. In
all but one of the X-ray detected groups, the X-ray emission is centered on a
luminous elliptical galaxy. Fits to the surface brightness profiles of the
X-ray emission suggest the presence of two X-ray components in these groups.
The first component is centered on the central elliptical galaxy. The location
and extent of this component, combined with its X-ray temperature and
luminosity, favor an origin in the interstellar medium of the central galaxy.
Alternatively, the central component may be the result of a large-scale cooling
flow. The second X-ray component is detected out to a radius of at least
100-300 kpc. This component follows the same relationships found among the
X-ray temperature, X-ray luminosity and optical velocity dispersion of rich
clusters. This result suggests that the X-ray detected groups are low-mass
versions of clusters and that the extended gas component can properly be called
the intragroup medium, in analogy to the intracluster medium in clusters. We
also find a trend for the position angle of the optical light in the central
elliptical galaxy to align with the position angle of the large-scale X-ray
emission. (Abridged)Comment: 38 pages, AASLaTeX with 16 PS figures. Figure 1a-1l available in
gzipped postscript format at ftp://corvus.ociw.edu/pub/mulchae
The Las Campanas/AAT Rich Cluster Survey III: Spectroscopic Studies of X-ray Bright Galaxy Clusters at z~0.1
[abridged] We present the analysis of the spectroscopic and photometric
catalogues of 11 X-ray luminous clusters at z=0.07-0.16 from the Las Campanas /
Anglo-Australian Telescope Rich Cluster Survey. Our spectroscopic dataset
consists of over 1600 galaxy cluster members, of which two thirds are outside
r_200. We assign cluster membership using a detailed mass model and expand on
our previous work on the cluster colour-magnitude relation where membership was
inferred statistically. We confirm that the modal colours of galaxies on the
colour magnitude relation become progressively bluer with increasing radius and
decreasing local galaxy density. Interpreted as an age effect, we hypothesize
that these trends in galaxy colour should be reflected in mean Hdelta
equivalent width. We confirm that passive galaxies in the cluster increase in
Hdelta line strength as dHdelta / d r_p = 0.35 +/- 0.06. A variation of star
formation rate, as measured by [OII], with increasing local density of the
environment is discernible and is shown to be in broad agreement with previous
studies from 2dFGRS and SDSS. We find that clusters at z~0.1 are less active
than their higher redshift analogues. We also investigate unusual populations
of blue and very red nonstarforming galaxies and we suggest that the former are
likely to be the progenitors of galaxies which will lie on the colour-magnitude
relation, while the colours of the latter possibly reflect dust reddening. The
cluster galaxies at large radii consist of both backsplash ones and those that
are infalling to the cluster for the first time. We make a comparison to the
field population at z~0.1 and examine broad differences between the two
populations. Individually, the clusters show significant variation in their
galaxy populations which reflects their recent infall histories.Comment: 25 pages, 16 figures. Accepted for publication in MNRA
Analysis of transcription factors key for mouse pancreatic development establishes NKX2-2 and MNX1 mutations as causes of neonatal diabetes in man
notes: PMCID: PMC3887257This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development.Wellcome TrustDiabetes UKEuropean Community’s Seventh Framework Programme (FP7/2007-2013
Hormonal signaling in cnidarians : do we understand the pathways well enough to know whether they are being disrupted?
Author Posting. © The Author, 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Ecotoxicology 16 (2007): 5-13, doi:10.1007/s10646-006-0121-1.Cnidarians occupy a key evolutionary position as basal metazoans and are ecologically
important as predators, prey and structure-builders. Bioregulatory molecules (e.g.,
amines, peptides and steroids) have been identified in cnidarians, but cnidarian signaling
pathways remain poorly characterized. Cnidarians, especially hydras, are regularly used
in toxicity testing, but few studies have used cnidarians in explicit testing for signal
disruption. Sublethal endpoints developed in cnidarians include budding, regeneration,
gametogenesis, mucus production and larval metamorphosis. Cnidarian genomic
databases, microarrays and other molecular tools are increasingly facilitating mechanistic
investigation of signaling pathways and signal disruption. Elucidation of cnidarian
signaling processes in a comparative context can provide insight into the evolution and
diversification of metazoan bioregulation. Characterizing signaling and signal disruption
in cnidarians may also provide unique opportunities for evaluating risk to valuable
marine resources, such as coral reefs
2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer
Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer
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