147 research outputs found

    Desertification

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    IPCC SPECIAL REPORT ON CLIMATE CHANGE AND LAND (SRCCL) Chapter 3: Climate Change and Land: An IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystem

    Quality assurance in stereotactic radiosurgery/radiotherapy according to DIN 6875-1

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    The new DIN (' Deutsche Industrie- Norm') 6875- 1, which is currently being finalised, deals with quality assurance ( QA) criteria and tests methods for linear accelerator and Gamma Knife stereotactic radiosurgery/ radiotherapy including treatment planning, stereotactic frame and stereotactic imaging and a system test to check the whole chain of uncertainties. Our existing QA program, based on dedicated phantoms and test procedures, has been refined to fulfill the demands of this new DIN. The radiological and mechanical isocentre corresponded within 0.2 mm and the measured 50% isodose lines were in agreement with the calculated ones within less than 0.5 mm. The measured absorbed dose was within 3%. The resultant output factors measured for the 14-, 8- and 4- mm collimator helmet were 0.9870 +/- 0.0086, 0.9578 +/- 0.0057 and 0.8741 +/- 0.0202, respectively. For 170 consecutive tests, the mean geometrical accuracy was 0.48 +/- 0.23 mm. Besides QA phantoms and analysis software developed in- house, the use of commercially available tools facilitated the QA according to the DIN 6875- 1 with which our results complied. Copyright (C) 2004 S. Karger AG, Basel

    The problem of motivation of students of the technical university to study chemistry

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    The article is devoted to studying of a problem of motivation to study chemistry in technical higher educational institutions. Examined the results of testing the peculiarities of the personality of students of the first course. Suggests ways to improve motivation towards learning chemistry

    Red Queen Coevolution on Fitness Landscapes

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    Species do not merely evolve, they also coevolve with other organisms. Coevolution is a major force driving interacting species to continuously evolve ex- ploring their fitness landscapes. Coevolution involves the coupling of species fit- ness landscapes, linking species genetic changes with their inter-specific ecological interactions. Here we first introduce the Red Queen hypothesis of evolution com- menting on some theoretical aspects and empirical evidences. As an introduction to the fitness landscape concept, we review key issues on evolution on simple and rugged fitness landscapes. Then we present key modeling examples of coevolution on different fitness landscapes at different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.). Springer Series in Emergence, Complexity, and Computation, 201

    Lead Slowing Down Spectrometer Status Report

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    This report documents the progress that has been completed in the first half of FY2012 in the MPACT-funded Lead Slowing Down Spectrometer project. Significant progress has been made on the algorithm development. We have an improve understanding of the experimental responses in LSDS for fuel-related material. The calibration of the ultra-depleted uranium foils was completed, but the results are inconsistent from measurement to measurement. Future work includes developing a conceptual model of an LSDS system to assay plutonium in used fuel, improving agreement between simulations and measurement, design of a thorium fission chamber, and evaluation of additional detector techniques

    How do “mental health professionals” who are also or have been “mental health service users” construct their identities?

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    “Mental health professionals” are increasingly speaking out about their own experiences of using mental health services. However, research suggests that they face identity-related dilemmas because social conventions tend to assume two distinct identities: “professionals” as relatively socially powerful and “patients” as comparatively powerless. The aim of this study was, through discourse analysis, to explore how “mental health professionals” with “mental health service user” experience “construct” their identity. Discourse analysis views identity as fluid and continually renegotiated in social contexts. Ten participants were interviewed, and the interviews were transcribed and analyzed. Participants constructed their identity variously, including as separate “professional” and “patient” identities, switching between these in relation to different contexts, suggesting “unintegrated” identities. Participants also demonstrated personally valued “integrated” identities in relation to some professional contexts. Implications for clinical practice and future research are explored. Positive identity discourses that integrate experiences as a service user and a professional included “personhood” and insider “activist,” drawing in turn on discourses of “personal recovery,” “lived experience,” and “use of self.” These integrated identities can potentially be foregrounded to contribute to realizing the social value of service user and other lived experience in mental health workers, and highlighting positive and hopeful perspectives on mental distress
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