3,186 research outputs found

    A Method for Broad-Scale Environmental Evaluation as Applied in an Environmental Analysis of Central Ohio

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    Author Institution: Ohio Biological SurveyA general but comprehensive environmental analysis of the environmental resources of a large region may be conducted utilizing an analysis/index matrix and maps of the analyzed resources. This methodology, previously applied to the 10,976 square mile Central Ohio Water Development Region, incorporates ecologically sound data in a format intelligible to decision makers. Resource maps of the region were completed with features rated, where possible, according to relative significance. Two gridded, summary, composite maps, one for natural components and one for human components, were then compiled. Each grid cell on the natural composite map indexes the significant features in that cell and the land use analog of the ecological serai stage (one of four categories) predominant in that cell. The analog is a comprehensive indicator of the relative degree of natural ecological integrity in the cell. Each grid cell on the human composite map indexes the significant features in that cell and the fair market land value category (one of four categories) predominant in the cell. The land value category is a comprehensive indicator of the human value attributed to that area. The two values for each grid cell on both composite maps are inserted into an analysis/index matrix to yield one of three final analysis/index values. These values, one from a natural perspective and one from a human perspective, indicate areas of overall, relative environmental importance. The natural and the human composite maps may be combined to indicate the areas of potential conflict and tradeoff between these two value systems

    MIS Legitimacy and the Proposition of a New Multi-dimensional Model of MIS

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    This paper addresses the definition of MIS and the legitimacy of MIS as an academic discipline. Both sides of the MIS legitimacy debate are presented, with the authors embracing the diversity of MIS as a strength that enhances the legitimacy of the MIS discipline. Based on the diversity theory of MIS, the authors propose a new-multidimensional model of MIS that presents a new way of looking at the discipline and the researchers who work in it

    Multiple Peer Group Self-identification and Adolescent Tobacco Use

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    Associations between peer group self-identification and smoking were examined among 2,698 ethnically diverse middle school students in Los Angeles who self-identified with groups such as Rockers, Skaters, and Gamers. The sample was 47.1% male, 54.7% Latino, 25.4% Asian, 10.8% White, 9.1% Other ethnicity, and 59.3% children of immigrant parents. Multiple group self identification was common: 84% identified with two or more groups and 65% identified with three or more groups. Logistic regression analyses indicated that as students endorsed more high risk groups, the greater their risk of tobacco use. A classification tree analysis identified risk groups based on interactions among ethnicity, gender, and group self-identification. Psychographic targeting based on group self-identification could be useful to design more relevant smoking prevention messages for adolescents who identify with high-risk peer groups

    The Major Histocompatibility Complex–related Fc Receptor for IgG (FcRn) Binds Albumin and Prolongs Its Lifespan

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    The inverse relationship between serum albumin concentration and its half-life suggested to early workers that albumin would be protected from a catabolic fate by a receptor-mediated mechanism much like that proposed for IgG. We show here that albumin binds FcRn in a pH dependent fashion, that the lifespan of albumin is shortened in FcRn-deficient mice, and that the plasma albumin concentration of FcRn-deficient mice is less than half that of wild-type mice. These results affirm the hypothesis that the major histocompatibility complex–related Fc receptor protects albumin from degradation just as it does IgG, prolonging the half-lives of both

    The Fragility of Quantum Information?

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    We address the question whether there is a fundamental reason why quantum information is more fragile than classical information. We show that some answers can be found by considering the existence of quantum memories and their dimensional dependence.Comment: Essay on quantum information: no new results. Ten pages, published in Lec. Notes in Comp. Science, Vol. 7505, pp. 47-56 (2012. One reference adde

    Fast stable direct fitting and smoothness selection for Generalized Additive Models

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    Existing computationally efficient methods for penalized likelihood GAM fitting employ iterative smoothness selection on working linear models (or working mixed models). Such schemes fail to converge for a non-negligible proportion of models, with failure being particularly frequent in the presence of concurvity. If smoothness selection is performed by optimizing `whole model' criteria these problems disappear, but until now attempts to do this have employed finite difference based optimization schemes which are computationally inefficient, and can suffer from false convergence. This paper develops the first computationally efficient method for direct GAM smoothness selection. It is highly stable, but by careful structuring achieves a computational efficiency that leads, in simulations, to lower mean computation times than the schemes based on working-model smoothness selection. The method also offers a reliable way of fitting generalized additive mixed models

    Acute SIV Infection in Sooty Mangabey Monkeys Is Characterized by Rapid Virus Clearance from Lymph Nodes and Absence of Productive Infection in Germinal Centers

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    Lymphoid tissue immunopathology is a characteristic feature of chronic HIV/SIV infection in AIDS-susceptible species, but is absent in SIV-infected natural hosts. To investigate factors contributing to this difference, we compared germinal center development and SIV RNA distribution in peripheral lymph nodes during primary SIV infection of the natural host sooty mangabey and the non-natural host pig-tailed macaque. Although SIV-infected cells were detected in the lymph node of both species at two weeks post infection, they were confined to the lymph node paracortex in immune-competent mangabeys but were seen in both the paracortex and the germinal center of SIV-infected macaques. By six weeks post infection, SIV-infected cells were no longer detected in the lymph node of sooty mangabeys. The difference in localization and rate of disappearance of SIV-infected cells between the two species was associated with trapping of cell-free virus on follicular dendritic cells and higher numbers of germinal center CD4+ T lymphocytes in macaques post SIV infection. Our data suggests that fundamental differences in the germinal center microenvironment prevent productive SIV infection within the lymph node germinal centers of natural hosts contributing to sustained immune competency
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