1,040 research outputs found

    To Promote the General Welfare.

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    Public welfare policy over the last two hundred years was examined in a series of lectures held at the University of Minnesota to celebrate the bicentennial of the United States Constitution. Papers by three of the distinguished scholars in the 1988 series are printed here: Michael B. Katz on Historic Obstacles to Welfare Reform; Gerald N. Grob on Public Policy and Mental Illness; and Lela B. Costin on Women, Children, and The General Welfare. In addition, H.E. Mason provides a written response to the entire series. A summary of the series appeared in the December 1988 CURA Reporter.Sponsored by the University of Minnesota's School of Social Work, Social Welfare History Archives, and Center for Urban and Regional Affairs, and held at the Hubert H. Humphrey Center, University of Minnesota, during October and November 1987

    QuizMap: Open social student modeling and adaptive navigation support with TreeMaps

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    In this paper, we present a novel approach to integrate social adaptive navigation support for self-assessment questions with an open student model using QuizMap, a TreeMap-based interface. By exposing student model in contrast to student peers and the whole class, QuizMap attempts to provide social guidance and increase student performance. The paper explains the nature of the QuizMap approach and its implementation in the context of self-assessment questions for Java programming. It also presents the design of a semester-long classroom study that we ran to evaluate QuizMap and reports the evaluation results. © 2011 Springer-Verlag Berlin Heidelberg

    Heavy-tailed kernels reveal a finer cluster structure in t-SNE visualisations

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    T-distributed stochastic neighbour embedding (t-SNE) is a widely used data visualisation technique. It differs from its predecessor SNE by the low-dimensional similarity kernel: the Gaussian kernel was replaced by the heavy-tailed Cauchy kernel, solving the "crowding problem" of SNE. Here, we develop an efficient implementation of t-SNE for a tt-distribution kernel with an arbitrary degree of freedom Îœ\nu, with Μ→∞\nu\to\infty corresponding to SNE and Îœ=1\nu=1 corresponding to the standard t-SNE. Using theoretical analysis and toy examples, we show that Îœ<1\nu<1 can further reduce the crowding problem and reveal finer cluster structure that is invisible in standard t-SNE. We further demonstrate the striking effect of heavier-tailed kernels on large real-life data sets such as MNIST, single-cell RNA-sequencing data, and the HathiTrust library. We use domain knowledge to confirm that the revealed clusters are meaningful. Overall, we argue that modifying the tail heaviness of the t-SNE kernel can yield additional insight into the cluster structure of the data

    Voting 'against all' in postcommunist Russia

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    Since the early 1990s voters in Russia (and most of the other post-Soviet republics) have been offered the opportunity to vote ‘against all’ parties and candidates. Increasing numbers have done so. The evidence of two post-election surveys indicates that ‘against all’ voters are younger than other voters, more urban and more highly educated. They do not reject liberal democracy, but are critical of the contemporary practice of Russian politics and find no parties that adequately reflect their views. With the ending of the ‘against all’ facility in 2006 and other changes in the Russian electoral system under the Putin presidency, levels of turnout are likely to fall further and the protest vote will seek other outlets within or outside the parliamentary system

    Phosphorylation-dependent translocation of sphingosine kinase to the plasma membrane drives its oncogenic signalling

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    Sphingosine kinase (SK) 1 catalyzes the formation of the bioactive lipid sphingosine 1-phosphate, and has been implicated in several biological processes in mammalian cells, including enhanced proliferation, inhibition of apoptosis, and oncogenesis. Human SK (hSK) 1 possesses high instrinsic catalytic activity which can be further increased by a diverse array of cellular agonists. We have shown previously that this activation occurs as a direct consequence of extracellular signal–regulated kinase 1/2–mediated phosphorylation at Ser225, which not only increases catalytic activity, but is also necessary for agonist-induced translocation of hSK1 to the plasma membrane. In this study, we report that the oncogenic effects of overexpressed hSK1 are blocked by mutation of the phosphorylation site despite the phosphorylation-deficient form of the enzyme retaining full instrinsic catalytic activity. This indicates that oncogenic signaling by hSK1 relies on a phosphorylation-dependent function beyond increasing enzyme activity. We demonstrate, through constitutive localization of the phosphorylation-deficient form of hSK1 to the plasma membrane, that hSK1 translocation is the key effect of phosphorylation in oncogenic signaling by this enzyme. Thus, phosphorylation of hSK1 is essential for oncogenic signaling, and is brought about through phosphorylation-induced translocation of hSK1 to the plasma membrane, rather than from enhanced catalytic activity of this enzyme
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