Distant Galaxy Clusters Identified From Optical Background Fluctuations

We present the first high redshift (0.3 < z < 1.1) galaxy clusters found by systematically identifying optical low surface brightness fluctuations in the background sky. Using spectra obtained with the Keck telescope and I-band images from the Palomar 1.5m telescope, we conclude that at least eight of the ten candidates examined are high redshift galaxy clusters. The identification of such clusters from low surface brightness fluctuations provides a complementary alternative to classic selection methods based on overdensities of resolved galaxies, and enables us to search efficiently for rich high redshift clusters over large areas of the sky. The detections described here are the first in a survey that covers a total of nearly 140 sq. degrees of the sky and should yield, if these preliminary results are representative, over 300 such clusters.Comment: Submitted to ApJ

Boundary layer flow of air over water on a flat plate

A non-similar boundary layer theory for air blowing over a water layer on a flat plate is formulated and studied as a two-fluid problem in which the position of the interface is unknown. The problem is considered at large Reynolds number (based on x), away from the leading edge. A simple non-similar analytic solution of the problem is derived for which the interface height is proportional to x(sub 1/4) and the water and air flow satisfy the Blasius boundary layer equations, with a linear profile in the water and a Blasius profile in the air. Numerical studies of the initial value problem suggests that this asymptotic, non-similar air-water boundary layer solution is a global attractor for all initial conditions

Development of a web-enabled learning platform for geospatial laboratories: improving the undergraduate learning experience

This paper describes a web-enabled learning platform providing remote access to geospatial software that extends the learning experience outside of the laboratory setting. The platform was piloted in two undergraduate courses, and includes a software server, a data server, and remote student users. The platform was designed to improve the quality of the learning experience and to increase student confidence and proficiency with software-based geospatial skills. Laboratory grades of students using the platform were significantly higher than those of students who did not use the platform, and survey responses reported that students overwhelmingly liked the convenience of the platform, which allowed them to work from any location

Cluster Galaxy Evolution from a New Sample of Galaxy Clusters at 0.3 < z < 0.9

(Abridged) We analyze photometry and spectroscopy of a sample of 63 clusters at 0.3<z<0.9 drawn from the Las Campanas Distant Cluster Survey to empirically constrain models of cluster galaxy evolution. Specifically, by combining data on our clusters with those from the literature we parametrize the redshift dependence of 1) M*_I in the observed frame; 2) the V-I color of the E/S0 red sequence in the observed frames; and 3) the I-K' color of the E/S0 red sequence in the observed frame. Using the peak surface brightness of the cluster detection, S, as a proxy for cluster mass, we find no correlation between S and M* or the location of the red envelope in V-I. We suggest that these observations can be explained with a model in which luminous early type galaxies (or more precisely, the progenitors of current day luminous early type galaxies) form the bulk of their stellar populations at high redshift (>~ 5) and in which many of these galaxies, if not all, accrete mass either in the form of evolved stellar populations or gas that causes only a short term episode of star formation at lower redshifts (1.5 < z < 2). Our data are too crude to reach conclusions regarding the evolutionary state of any particular cluster or to investigate whether the morphological evolution of galaxies matches the simple scenario we discuss, but the statistical nature of this study suggests that the observed evolutionary trends are universal in massive clusters.Comment: 35 pages, accepted for publication in Ap

The Path to Eliminating Raccoon Rabies in the Eastern US-Obstacles and Opportunities in Urban-Suburban Landscapes

Rabies in terrestrial wildlife poses a significant public and animal health threat. Oral rabies vaccination (ORV) targeting specific vector species has proven effective in eliminating certain rabies variants in Europe and Canada. The goal of eliminating the raccoon rabies variant (RRV) in the US is achievable through an integrated ORV program at the landscape scale. Current wildlife rabies management in the US includes extensive air and ground ORV programs in 16 eastern states coordinated by Wildlife Services (WS)’ National Rabies Management Program. More than 10 million vaccine-baits are distributed annually targeting raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) with the long-term goal of eliminating RRV. Achieving vaccine-induced herd immunity in target species in developed landscapes has proven challenging due to abundant anthropogenic food sources, higher wildlife densities, decreased home ranges, habitat fragmentation, and non-target bait competition. Effectively managing RRV in the urban-suburban landscape requires greater understanding of meso-carnivore ecology in these landscapes and critical analyses of current baiting strategies. Preliminary results from urban-suburban studies demonstrate fewer potential ORV bait encounters for target species than expected, lower seroconversion rates compared to rural habitats and patchy bait distribution patterns. New technologies including the use of Point of Interest GPS units to document ground bait distribution in combination with research conducted by WS including ORV field trials, urban density studies, and raccoon, skunk, and opossum (Didelphis virginiana) ecology have provided valuable insight to overcome the obstacles of urban rabies management and make eliminating RRV a reality

Constraints On the Size Evolution of Brightest Cluster Galaxies

We measure the luminosity profiles of 16 brightest cluster galaxies (BCGs) at $0.4 < z < 0.8$ using high resolution F160W NICMOS and F814W WFPC2 HST imaging. The heterogeneous sample is drawn from a variety of surveys: seven from clusters in the Einstein Medium Sensitivity Survey, five from the Las Campanas Distant Cluster Survey and its northern hemisphere precursor, and the remaining four from traditional optical surveys. We find that the surface brightness profiles of all but three of these BCGs are well described by a standard de Vaucouleurs ($r^{1/4}$) profile out to at least $\sim2r_{e}$ and that the biweight-estimated NICMOS effective radius of our high redshift BCGs ($r_{e} = 8.3\pm 1.4$ kpc for $H_{0} = 80$ km s$^{-1}$ Mpc$^{-1}$, $\Omega_{m} = 0.2, \Omega_\Lambda = 0.0$) is $\sim 2$ times smaller than that measured for a local BCG sample. If high redshift BCGs are in dynamical equilibrium and satisfy the same scaling relations as low redshift ones, this change in size would correspond to a mass growth of a factor of 2 since $z \sim 0.5$. However, the biweight-estimated WFPC2 effective radius of our sample is 18 $\pm$ 5.1 kpc, which is fully consistent with the local sample. While we can rule out mass accretion rates higher than a factor of 2 in our sample, the discrepancy between our NICMOS and WFPC2 results, which after various tests we describe appears to be physical, does not yet allow us to place strong constraints on accretion rates below that level.Comment: ApJ accepted (566, 1, February 2002), 12 pages, uses emulateapj5.st

Association of the functional ovarian reserve with serum metabolomic profiling by nuclear magnetic resonance spectroscopy:A cross sectional study of ~400 women

Background: Women with diminished ovarian reserve are known to have increased cardiovascular risk, whether there is a continuous association between the ovarian reserve biomarkers; anti-Müllerian hormone (AMH), antral follicle count (AFC) and cardio-metabolic risk factors are unknown. Methods: A cross-sectional study of 398 women intending to undergo IVF with pre-treatment early follicular AMH and AFC measurements. Serum lipids, lipoprotein subclasses and low-molecular-weight metabolites were quantified by NMR spectroscopy (155 metabolic measures). Associations were analysed using multivariable regression. Results: Participants were mean 35.5 (SD 4.43) years old and had a median AMH of 16 pmol/l (IQR 8.8, 28.0 pmol/l) and a median AFC of 12 (IQR 7.16). AMH showed positive associations with HDL, omega-6 and polyunsaturated fatty acids and the amino acids isoleucine, leucine and tyrosine, with effects ranging from 0.11 (95%CI 0.004 to 0.21) for total lipids in small HDL to 0.16 (0.06 to 0.26) for isoleucine, for a mean difference of one SD of metabolite per one SD increment in AMH, and negatively with acetate: − 0.31(− 0.22, − 0.004) SD per 1 SD AMH. AFC was positively associated with alanine, glutamine and glycine. Results were consistent, though less precisely estimated, when restricted to those women who were preparing for treatment because of their partner’s infertility. Conclusions: In women intending to have IVF, AMH and AFC were not associated with traditional lipid measured but were associated with a number of novel cardiovascular risk factors. Prospective studies will be required for replication, determination of causality and confirmation that ovarian reserve is impacting on metabolism rather than variation in metabolism is influencing ovarian reserve