2,051 research outputs found

    Dependence of simulated radiation damage on crystal structure and atomic misfit in metals

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    This study investigates radiation damage in three metals in the low temperature and high radiant flux regime using molecular dynamics and a Frenkel pair accumulation method to simulate up to 2.02.0 displacements per atom. The metals considered include Fe, equiatomic CrCoNi, and a fictitious metal with identical bulk properties to the CrCoNi composed of a single atom type referred to as an A-atom. CrCoNi is found to sustain higher concentrations of dislocations than either the Fe or A-atom systems and more stacking faults than the A-atom system. The results suggest that the concentration of vacancies and interstitials are substantially higher for the CrCoNi than the A-atom system, perhaps reflecting that the recombination radius is smaller in CrCoNi due to the roughened potential energy landscape. A model that partitions the major contributions from defects to the stored energy is described, and serves to highlight a general need for higher fidelity approaches to point defect identification

    Spatial Contours of Potential Biomass Crop Production: An Examination of Variations by U.S. Region

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    The recent and projected status of energy production and consumption in the United States, resulting in substantial dependencies upon foreign oil, has continued to provide pressure on domestic energy security. All told, bio-energy systems, and biomass crop production in particular, will be important elements of national security, economic vitality, and public policy. Using biomass crop estimates based upon models developed at the Oak Ridge National Laboratory and the Department of Energy (DOE) National Renewable Energy Laboratory, we identify potential biomass crop production zones using spatial analysis methods. The Midwest and the South are, by far, the largest regions of potential production. Once potential biomass crop yield is made proportional to estimated land and production costs, the South’s optimal crop zones fall along the Gulf Coast and Atlantic Seaboard, whereas in the Midwest, they are largely in non-metropolitan localities. The implications of these spatial contours for energy policy for alternative biomass crop production are discussed

    Missouri 2011 Soft Red Winter Wheat Performance Tests

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    This report is published by the MU Variety Testing Program, Division of Plant Sciences, University of Missouri. The work was supported by fees from companies and organizations submitting varieties for evaluation. The large number of varieties available makes selection of a superior variety difficult. To select intelligently, producers need a reliable, unbiased, up-to-date source of information that will permit valid comparisons among available varieties. The objective of the MU Variety Testing Program is to provide this information. Tests are conducted under as close to uniform conditions as possible. Small plots are used to reduce the chance of soil and other variations occurring among variety plots. Results obtained should aid individual growers in judging the relative merits of many of the commercial wheat varieties available in Missouri

    Missouri 2011 Corn Performance Tests

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    This report is published by the MU Variety Testing Program, Division of Plant Sciences, University of Missouri. The work was supported by fees provided by companies submitting hybrids for evaluation. The University of Missouri's hybrid performance testing program began in the mid-1930s, with results first published in 1937. The number of entries in the program has grown from fewer than 50 in the early years to more than 250 today. The large number of commercial hybrids available makes selection of a superior hybrid difficult. To select intelligently, producers need a reliable, unbiased, up-to-date source of information that will permit valid comparisons among available hybrids. The objective of the MU Variety Testing Program is to provide this information

    Systematic review of economic evaluations and cost analyses of guideline implementation strategies

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    Objectives To appraise the quality of economic studies undertaken as part of evaluations of guideline implementation strategies; determine their resources use; and recommend methods to improve future studies. Methods Systematic review of economic studies undertaken alongside robust study designs of clinical guideline implementation strategies published (1966-1998). Studies assessed against the BMJ economic evaluations guidelines for each stage of the guideline process (guideline development, implementation and treatment). Results 235 studies were identified, 63 reported some information on cost. Only 3 studies provided evidence that their guideline was effective and efficient. 38 reported the treatment costs only, 12 implementation and treatment costs, 11 implementation costs alone, and two guideline development, implementation and treatment costs. No study gave reasonably complete information on costs. Conclusions Very few satisfactory economic evaluations of guideline implementation strategies have been performed. Current evaluations have numerous methodological defects and rarely consider all relevant costs and benefits. Future evaluations should focus on evaluating the implementation of evidence based guidelines. Keywords: Cost-effectiveness analysis, physician (or health care professional) behaviour, practice guidelines, quality improvement, systematic review.Peer reviewedAuthor versio

    PDX Finder: A portal for patient-derived tumor xenograft model discovery.

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    Patient-derived tumor xenograft (PDX) mouse models are a versatile oncology research platform for studying tumor biology and for testing chemotherapeutic approaches tailored to genomic characteristics of individual patients\u27 tumors. PDX models are generated and distributed by a diverse group of academic labs, multi-institution consortia and contract research organizations. The distributed nature of PDX repositories and the use of different metadata standards for describing model characteristics presents a significant challenge to identifying PDX models relevant to specific cancer research questions. The Jackson Laboratory and EMBL-EBI are addressing these challenges by co-developing PDX Finder, a comprehensive open global catalog of PDX models and their associated datasets. Within PDX Finder, model attributes are harmonized and integrated using a previously developed community minimal information standard to support consistent searching across the originating resources. Links to repositories are provided from the PDX Finder search results to facilitate model acquisition and/or collaboration. The PDX Finder resource currently contains information for 1985 PDX models of diverse cancers including those from large resources such as the Patient-Derived Models Repository, PDXNet and EurOPDX. Individuals or organizations that generate and distribute PDXs are invited to increase the \u27findability\u27 of their models by participating in the PDX Finder initiative at www.pdxfinder.org
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