4,271 research outputs found
Measurement of the Mass Profile of Abell 1689
In this letter we present calibrated mass and light profiles of the rich
cluster of galaxies Abell 1689 out to 1 Mpc from the center. The high
surface density of faint blue galaxies at high redshift, selected by their low
surface brightness, are unique tools for mapping the projected mass
distribution of foreground mass concentrations. The systematic gravitational
lens distortions of of these background galaxies in 15\arcmin\ fields
reveal detailed mass profiles for intervening clusters of galaxies, and are a
direct measure of the growth of mass inhomogeneity. The mass is measured
directly, avoiding uncertainties encountered in velocity or X-ray derived mass
estimates.
Mass in the rich cluster Abell 1689 follows smoothed light, outside 100
h kpc, with a rest-frame V band mass-to-light ratio of
. Near the cluster center, mass appears to be more
smoothly distributed than light. Out to a radius of 1 Mpc the total
mass follows a steeper than isothermal profile. Comparing with preliminary high
resolution N-body clustering simulations for various cosmogonies on these
scales, these data are incompatible with hot dark matter, a poor fit to most
mixed dark matter models, and favor open or cold dark matter.
Substructure is seen in both the mass and the light, but detailed
correspondence is erased on scales less than 100 kpc.Comment: 13 pages, uuencoded, compressed postscript file, 2 figures included
additional 1Mbyte figure available on request. Only change is that in
original errorbars on Fig. 5 were a factor of 2 too big
Hispanic Ethnicity Is Associated With Increased Hospital Charges After Radical Cystectomy in the United States
Objective: To examine the impact of race and ethnicity on financial charges associated with radical cystectomy (RC).
Data Sources/Study Setting: The Nationwide Inpatient Sample was used to identify patients who underwent RC for bladder cancer between 1998 and 2010.
Study Design: The primary outcome was total hospital charges adjusted for inflation. Multivariate analysis was performed using a generalized linear model on the logarithmically transformed outcome variable (total hospital charges) after adjusting for age, sex, race, Elixhauser comorbidities, surgical approach, year, primary payer, hospital and surgeon annual RC volume, hospital characteristics, and postoperative complications.
Principle findings: A total of 14,873 patients were identified. Hispanic and black patients were more likely to be treated by low-volume surgeons and/or institutions (both P=.07).
Conclusions: Hispanic ethnicity but not black race predicts higher hospital charges after RC
Fine Grained Component Engineering of Adaptive Overlays: Experiences and Perspectives
Recent years have seen significant research being carried out into peer-to-peer (P2P) systems. This work has focused on the styles and applications of P2P computing, from grid computation to content distribution; however, little investigation has been performed into how these systems are built. Component based engineering is an approach that has seen successful deployment in the field of middleware development; functionality is encapsulated in âbuilding blocksâ that can be dynamically plugged together to form complete systems. This allows efficient, flexible and adaptable systems to be built with lower overhead and development complexity. This paper presents an investigation into the potential of using component based engineering in the design and construction of peer-to-peer overlays. It is highlighted that the quality of these properties is dictated by the component architecture used to implement the system. Three reusable decomposition architectures are designed and evaluated using Chord and Pastry case studies. These demonstrate that significant improvements can be made over traditional design approaches resulting in much more reusable, (re)configurable and extensible systems
Annie Proulx\u27s Wyoming: Subversive Storytelling from the Bunchgrass Edge of the World
Annie Proulxâs three Wyoming short story collections, Close Range, Bad Dirt, and Fine Just the Way It Is, tell regional stories that push against the myths surrounding the American West. Elements of Naturalism in her work reverse the paradigm of manâs dominance over the frontier. The cyclical nature of time in her stories shows the unfulfilling nature of nostalgia. She uses folk storytelling techniques to take an insiderâs perspective and to utilize the subversive nature of dark humor
How to measure pain in neurological conditions? A systematic review of psychometric properties and clinical utility
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