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Search Results: 1 - 10 of 15000 matches for " William Richardson "
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Formation of Compact Clusters from High Resolution Hybrid Cosmological Simulations
Mark L. A. Richardson,Evan Scannapieco,William J. Gray
Physics , 2013, DOI: 10.1088/0004-637X/778/1/80
Abstract: The early Universe hosted a large population of small dark matter `minihalos' that were too small to cool and form stars on their own. These existed as static objects around larger galaxies until acted upon by some outside influence. Outflows, which have been observed around a variety of galaxies, can provide this influence in such a way as to collapse, rather than disperse the minihalo gas. Gray & Scannapieco performed an investigation in which idealized spherically-symmetric minihalos were struck by enriched outflows. Here we perform high-resolution cosmological simulations that form realistic minihalos, which we then extract to perform a large suite of simulations of outflow-minihalo interactions including non-equilibrium chemical reactions. In all models, the shocked minihalo forms molecules through non-equilibrium reactions, and then cools to form dense chemically homogenous clumps of star-forming gas. The formation of these high-redshift clusters will be observable with the next generation of telescopes, and the largest of them should survive to the present day, having properties similar to halo globular clusters.
Concentra??es de am?nio na água da chuva e estimativa de emiss?o de am?nia de rebanhos domésticos de Pinheiro e Viana, Baixada Maranhense
Lima, Richardson G.;Cavalcante, Paulo R. S.;Melo, Odilon T.;Mello, William Z. de;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000900006
Abstract: rainwater samples (bulk deposition samples) were collected in pinheiro and viana. rainwater phs were higher than the range usually expected for unpolluted rain (5.0-5.6). the highest values were found in the beginning of the rainy season. high concentrations of ammonium found in the rainwater samples could probably explain the high phs. grazing animals and other human activities, combined with soil characteristics and climatic conditions can be the potential factors controlling the rainwater concentrations of ammonium in baixada maranhense.
Sternal non-union in a professional hockey player: considerations for return to play
Samuel Mark Sanders,John Richardson, Jr,William Hartrich,Leslie J Bisson
Orthopedic Reviews , 2009, DOI: 10.4081/or.2009.e6
Abstract: We describe a healthy 40-year old professional hockey player with an asymptomatic sternal non-union following aortic root surgery. The purpose of this case report is to make orthopedic surgeons aware of the possibility of this complication following sternotomy, and to discuss the considerations involved in return to play in contact sports. We will discuss our work-up, evaluation, and management of a sternal non-union in a professional athlete. Patient’s consent has been obtained.
Rivermouth Alteration of Agricultural Impacts on Consumer Tissue δ15N
James H. Larson, William B. Richardson, Jon M. Vallazza, John C. Nelson
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069313
Abstract: Terrestrial agricultural activities strongly influence riverine nitrogen (N) dynamics, which is reflected in the δ15N of riverine consumer tissues. However, processes within aquatic ecosystems also influence consumer tissue δ15N. As aquatic processes become more important terrestrial inputs may become a weaker predictor of consumer tissue δ15N. In a previous study, this terrestrial-consumer tissue δ15N connection was very strong at river sites, but was disrupted by processes occurring in rivermouths (the ‘rivermouth effect’). This suggested that watershed indicators of N loading might be accurate in riverine settings, but could be inaccurate when considering N loading to the nearshore of large lakes and oceans. In this study, the rivermouth effect was examined on twenty-five sites spread across the Laurentian Great Lakes. Relationships between agriculture and consumer tissue δ15N occurred in both upstream rivers and at the outlets where rivermouths connect to the nearshore zone, but agriculture explained less variation and had a weaker effect at the outlet. These results suggest that rivermouths may sometimes be significant sources or sinks of N, which would cause N loading estimates to the nearshore zone that are typically made at discharge gages further upstream to be inaccurate. Identifying definitively the controls over the rivermouth effect on N loading (and other nutrients) will require integration of biogeochemical and hydrologic models.
A Bayesian Model of NMR Spectra for the Deconvolution and Quantification of Metabolites in Complex Biological Mixtures
William Astle,Maria De Iorio,Sylvia Richardson,David Stephens,Timothy Ebbels
Quantitative Biology , 2011,
Abstract: Nuclear Magnetic Resonance (NMR) spectra are widely used in metabolomics to obtain profiles of metabolites dissolved in biofluids such as cell supernatants. Methods for estimating metabolite concentrations from these spectra are presently confined to manual peak fitting and to binning procedures for integrating resonance peaks. Extensive information on the patterns of spectral resonance generated by human metabolites is now available in online databases. By incorporating this information into a Bayesian model we can deconvolve resonance peaks from a spectrum and obtain explicit concentration estimates for the corresponding metabolites. Spectral resonances that cannot be deconvolved in this way may also be of scientific interest so we model them jointly using wavelets. We describe a Markov chain Monte Carlo algorithm which allows us to sample from the joint posterior distribution of the model parameters, using specifically designed block updates to improve mixing. The strong prior on resonance patterns allows the algorithm to identify peaks corresponding to particular metabolites automatically, eliminating the need for manual peak assignment. We assess our method for peak alignment and concentration estimation. Except in cases when the target resonance signal is very weak, alignment is unbiased and precise. We compare the Bayesian concentration estimates to those obtained from a conventional numerical integration method and find that our point estimates have sixfold lower mean squared error. Finally, we apply our method to a spectral dataset taken from an investigation of the metabolic response of yeast to recombinant protein expression. We estimate the concentrations of 26 metabolites and compare to manual quantification by five expert spectroscopists. We discuss the reason for discrepancies and the robustness of our methods concentration estimates.
Power Spectral Analysis of Orthogonal Pulse-Based TH-UWB Signals  [PDF]
Sudhan Majhi, Paul Richardson
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2011.311114
Abstract: The paper analyzes power spectral density (PSD) of orthogonal pulse-based signals for time hopping ultra wideband (TH-UWB) systems. Our extensive studies show that the PSD of these signals not only depends on the time dithering code and the modulation schemes, but also on the energy spectral density (ESD) of orthogonal pulses. The different order orthogonal pulses provide different ESD which changes the shape of continuous spectral component with symbols. We show that orthogonal pulse-based signals reduce the dynamic range of amplitude of discrete spectral components. Further, we reduce the dynamic range by adopting longer TH code over orthogonal pulse-based signals. As a result, UWB system performance improves with average transmitted power. The theoretical analysis of PSD of orthogonal pulse-based TH-UWB signal is provided in details and verified through simulation results.
Cost and Emissions Implications of Coupling Wind and Solar Power  [PDF]
Seth Blumsack, Kelsey Richardson
Smart Grid and Renewable Energy (SGRE) , 2012, DOI: 10.4236/sgre.2012.34041
Abstract: We assess the implications on long-run average energy production costs and emissions of CO2 and some criteria pollutants from coupling wind, solar and natural gas generation sources. We utilize five-minute meteorological data from a US location that has been estimated to have both high-quality wind and solar resources, to simulate production of a coupled generation system that produces a constant amount of electric energy. The natural gas turbine is utilized to provide fill-in energy for the coupled wind/solar system, and is compared to a base case where the gas turbine produces a constant power output. We assess the impacts on variability of coupled wind and solar over multiple time scales, and compare this variability with regional demand in a nearby load center, and find that coupling wind and solar does decrease variability of output. The cost analysis found that wind energy with gas back-up has a lower levelized cost of energy than using gas energy alone, resulting in production savings. Adding solar energy to the coupled system increases levelized cost of energy production; this cost is not made up by any reductions in emissions costs.
An Implementation of the Japanese Autobiographical Method Seikatsu Tsuzurikata—“Life Writing”—In a US Elementary School  [PDF]
Scott Richardson, Haruka Konishi
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.49080
Abstract:

This article explores the historical, philosophical, curricular, and practical methods of the Japanese auto-biographical method, “seikatusu tsuzurikata” and its implementation in a US elementary school. Seikatsu tsuzurikata is a progressive form of journaling that “provokes students to ‘objectively’ observe the reality surrounding them in terms of their own senses without any intervention of anyone else’s authority”, by writing essays “reflecting on their social situation” (Asanuma, 1986: pp. 153, 155). Part of life writing’s central philosophy is that students are not required to participate. For students who engaged in life writing, several benefits resulted, according to their teachers. However, we found that students had great difficulty articulating their social and emotional worlds because this kind of reflective work was uncomfortable and foreign to students who were subjected to teacher-driven, “content”, and “standards based” instruction. This article concludes by exploring the possibility of connecting life writing with social-emotional learning (SEL).

Dbx1-Expressing Cells Are Necessary for the Survival of the Mammalian Anterior Neural and Craniofacial Structures
Frédéric Causeret,Monica Ensini,Anne Teissier,Nicoletta Kessaris,William D. Richardson,Thibaut Lucas de Couville,Alessandra Pierani
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0019367
Abstract: Development of the vertebrate forebrain and craniofacial structures are intimately linked processes, the coordinated growth of these tissues being required to ensure normal head formation. In this study, we identify five small subsets of progenitors expressing the transcription factor dbx1 in the cephalic region of developing mouse embryos at E8.5. Using genetic tracing we show that dbx1-expressing cells and their progeny have a modest contribution to the forebrain and face tissues. However, their genetic ablation triggers extensive and non cell-autonomous apoptosis as well as a decrease in proliferation in surrounding tissues, resulting in the progressive loss of most of the forebrain and frontonasal structures. Targeted ablation of the different subsets reveals that the very first dbx1-expressing progenitors are critically required for the survival of anterior neural tissues, the production and/or migration of cephalic neural crest cells and, ultimately, forebrain formation. In addition, we find that the other subsets, generated at slightly later stages, each play a specific function during head development and that their coordinated activity is required for accurate craniofacial morphogenesis. Our results demonstrate that dbx1-expressing cells have a unique function during head development, notably by controlling cell survival in a non cell-autonomous manner.
Duke Surgery Patient Safety: an open-source application for anonymous reporting of adverse and near-miss surgical events
Ricardo Pietrobon, Raquel Lima, Anand Shah, Danny O Jacobs, Matthew Harker, Mariana McCready, Henrique Martins, William Richardson
Annals of Surgical Innovation and Research , 2007, DOI: 10.1186/1750-1164-1-5
Abstract: To describe the Web-application Duke Surgery Patient Safety, designed for the anonymous reporting of adverse and near-miss events as well as scheduled reporting to surgeons and hospital administration.DSPS was developed primarily using Java language running on a Tomcat server and with MySQL database as its backend.Formal and field usability tests were used to aid in development of DSPS. Extensive experience with DSPS at our institution indicate that DSPS is easy to learn and use, has good speed, provides needed functionality, and is well received by both adverse-event reporters and administrators.This is the first description of an open-source application for reporting patient safety, which allows the distribution of the application to other institutions in addition for its ability to adapt to the needs of different departments. DSPS provides a mechanism for anonymous reporting of adverse events and helps to administer Patient Safety initiatives.The modifiable framework of DSPS allows adherence to evolving national data standards. The open-source design of DSPS permits surgical departments with existing reporting mechanisms to integrate them with DSPS. The DSPS application is distributed under the GNU General Public License.Near miss events occur in every medical facility all over the world. Studies have shown that 4% of hospitalized patients suffer from an adverse event caused by the medical treatment administered [1,2]. These mistakes can result in patient discomfort, irreversible injury, or even death. Although patient safety is a topic of major emphasis for medical facilities, efforts to investigate the causes and prevention of these errors have been insufficient, reflecting a general lack of awareness of the problem [2]. As a consequence of this oversight, the need for effectively collecting and understanding data about these adverse events is paramount in improving patient safety. Some institutions have created systems to encourage medical workers to report th
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