931 research outputs found

    Анализ систем оценки информационно коммуникационных компетенций

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    The article considers the methods of development of information-analytical system of formation of information-communicative competence of students through the portal of "Electronic University of information technology"

    Zeitbereichs-Modellreduktion und Sylvester-Gleichungen

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    Optimization-Based Parametric Model Order Reduction via H<sub>2</sub> ⊗ L<sub>2</sub> First-Order Necessary Conditions

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    QTLs for the elongation of axile and lateral roots of maize in response to low water potential

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    Changes in root architecture and the maintenance of root growth in drying soil are key traits for the adaptation of maize (Zea mays L.) to drought environments. The goal of this study was to map quantitative trait loci (QTLs) for root growth and its response to dehydration in a population of 208 recombinant inbred lines from the International Maize and Wheat Improvement Center (CIMMYT). The parents, Ac7643 and Ac7729/TZSRW, are known to be drought-tolerant and drought-sensitive, respectively. Roots were grown in pouches under well-watered conditions or at low water potential induced by the osmolyte polyethylene glycol (PEG 8000). Axile root length (L Ax) increased linearly, while lateral root length (L Lat) increased exponentially over time. Thirteen QTLs were identified for six seedling traits: elongation rates of axile roots (ERAx), the rate constant of lateral root elongation (k Lat), the final respective lengths (L Ax and L Lat), and the ratios k Lat/ERAx and L Lat/L Ax. While QTLs for lateral root traits were constitutively expressed, most QTLs for axile root traits responded to water stress. For axile roots, common QTLs existed for ERAx and L Ax. Quantitative trait loci for the elongation rates of axile roots responded more clearly to water stress compared to root length. Two major QTLs were detected: a QTL for general vigor in bin 2.02, affecting most of the traits, and a QTL for the constitutive increase in k Lat and k Lat/ERAx in bins 6.04-6.05. The latter co-located with a major QTL for the anthesis-silking interval (ASI) reported in published field experiments, suggesting an involvement of root morphology in drought tolerance. Rapid seedling tests are feasible for elucidating the genetic response of root growth to low water potential. Some loci may even have pleiotropic effects on yield-related traits under drought stres

    Learning from the Past, Looking to the Future: Modeling Social Unrest in Karachi, Pakistan

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    Social unrest represents a major challenge for policy makers around the globe, as it can quickly escalate from small scale disturbances to highly public protests, riots and even civil war. This research was motivated by a need to understand social instability and to unpack the comments made during a spring 2013 conference hosted by Pacific Northwest National Laboratory’s Center for Global Security and the U.S. Institute for Peace, where policymakers noted that models considering social instability are often not suitable for decision-making. This analysis shows that existing state level models of instability could be improved in spatial scale to the city level, even without significantly improved data access. Better data would make this analysis more complete and likely improve the quality of the model. Another challenge with incorporating modeling into decision-making is the need to understand uncertainty in a model. Policy makers are frequently tasked with making decisions without a clear outcome, so characterization of uncertainty is critical. This report describes the work and findings of the project. It took place in three phases: a literature review of social stability research, a “hindsight scan” that looked at historical data, and a “foresight scan” looking at future scenarios

    Reading-specific flexibility moderates the relation between reading strategy use and reading comprehension during the elementary years

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    The goal was to test whether cognitive flexibility moderates the relation between reading strategy use and reading comprehension during the elementary years. Seventy-five second through fifth grade students completed a think aloud task and a metacognitive questionnaire to measure reading strategies, two card-sorting tasks to measure general and reading-specific cognitive flexibility, and one standardized measure of reading comprehension, as well as measures of oral reading fluency and vocabulary. As expected, oral reading fluency and vocabulary predicted reading comprehension, as did reading-specific flexibility. Importantly, reading-specific flexibility had a significant moderating effect, over and above the other effects. Specifically, weak reading-specific flexibility skills were associated with a negative relation between reading strategy use during think aloud and reading comprehension, suggesting that children with weak flexibility skills are less adept at using reading strategies effectively
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