4,478 research outputs found

    Optimal statistical inference in the presence of systematic uncertainties using neural network optimization based on binned Poisson likelihoods with nuisance parameters

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    Data analysis in science, e.g., high-energy particle physics, is often subject to an intractable likelihood if the observables and observations span a high-dimensional input space. Typically the problem is solved by reducing the dimensionality using feature engineering and histograms, whereby the latter technique allows to build the likelihood using Poisson statistics. However, in the presence of systematic uncertainties represented by nuisance parameters in the likelihood, the optimal dimensionality reduction with a minimal loss of information about the parameters of interest is not known. This work presents a novel strategy to construct the dimensionality reduction with neural networks for feature engineering and a differential formulation of histograms so that the full workflow can be optimized with the result of the statistical inference, e.g., the variance of a parameter of interest, as objective. We discuss how this approach results in an estimate of the parameters of interest that is close to optimal and the applicability of the technique is demonstrated with a simple example based on pseudo-experiments and a more complex example from high-energy particle physics

    Financial Exploitation of the Elderly

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    Adaptive Technomythography: The Apotheosis Of Machine And Development Of Legend In A System Of Dynamic Technology

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    Human beings will effectively deify any suitably complex system that cannot be explained through basic haptic interaction. Our culture loves technology. These days it seems we need it to feel whole. In an effort to explore the development of mythology and modular aesthetic in a technological age I have designed and constructed a number of interactive robotic \u27organisms\u27 to engage in arbitrary movement in geometric enclosures. Through observation and dialog I seek to assess the extent to which people assign human characteristics to the random and oft times aberrant mechanical behavior. To supplement this endeavor, a fictional astrological system that proposes logical (albeit mythological) explanations for the peculiarities in these relationships has been created

    A Semantic Map for Evaluating Creativity

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    We present a semantic map of words related with creativity. The aim is to empirically derive terms which can be used to rate processes or products of computational creativity. The words in the map are based on association studies performed by human subjects and augmented with words derived from the literature (based on human raters). The words are used in a card sorting study to investigate the way they are categorized by human subjects. The results are arranged in a heat map of word relations based on a hierarchical cluster analysis. The cluster analysis and a principal component analysis provide a set of five to six clusters of items related to each other, and as clusters related to creativity. These clusters could form a basis for scales used to rate aspects of computational creativity

    Performance Evaluation of Four Field-Scale Agricultural Drainage Denitrification Bioreactors in Iowa

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    Recently, interest in denitrification bioreactors to reduce the amount of nitrate in agricultural drainage has led to increased installations across the U.S. Midwest. Despite this recent attention, there are few peer-reviewed, field-scale comparative performance studies investigating the effectiveness of these denitrification bioreactors. The object of this work was to analyze nitrate removal performance from four existing bioreactors in Iowa, paying particular attention to potential performance-affecting factors including retention time, influent nitrate concentration, temperature, flow rate, age, length-to-width ratio, and cross-sectional shape. Based on a minimum of two years of water quality data from each of the four bioreactors, annual removal rates ranged from 0.38 to 7.76 g N m-3 bioreactor volume d-1. Bioreactor and total (including bypass flow) nitrate-nitrogen load reductions ranged from 12% to 76% (mean 45%) and from 12% to 57% (mean 32%), respectively, removing from 0.5 to 15.5 kg N ha-1 drainage area. Multiple regression analyses showed that temperature and influent nitrate concentration were the most important factors affecting percent bioreactor nitrate load reduction and nitrate removal rate, respectively. This analysis also indicated that load reductions within the bioreactor were significantly impacted by retention time at three of the four reactors. More field-scale performance data from bioreactors of different designs and from multiple locations around the Midwest are necessary to further enhance understanding of nitrate removal in these systems and their potential to positively impact water quality

    Characterization of a plasminogen activator and its inhibitor in human mesangial cells

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    Characterization of a plasminogen activator and its inhibitor in human mesangial cells. In the course of some pathological and experimental nephropathies, intraglomerular fibrin deposits develop, possibly as a consequence of inefficient fibrinolysis. In vitro human glomeruli exhibit fibrinolytic activity due to the synthesis of plasminogen activators (PAs) such as, tissue-type PA (t-PA) and urokinase-type PA (u-PA). Immunofluorescence studies have previously shown that t-PA is localized in the capillary tufts and u-PA in the visceral epithelial cells. We have now investigated the fibrinolytic activity of cultured human mesangial cells. Inhibitory activity towards u-PA or t-PA but not plasmin was found in both conditioned medium and cellular extracts. Analysis of the conditioned medium by zymography revealed a single band of PA-activity (Mr: 110 to 120 kDa). Immunoneutralization with anti-t-PA and antiplasminogen activator inhibitor (PAI-1) IgG but not anti-u-PA or anti-PAI-2 removed this band. Reverse fibrin autography demonstrated the presence of PAI-1 in both cellular extracts and in conditioned medium. Western Blot analysis showed that two bands (50 kD and 120 kD) were recognized by the anti-PAI-1 antibody. By ELISA t-PA and PAI-1 antigens were found to increase progressively with time in the culture medium but not in cellular extracts. Both t-PA and PAI-1, but not u-PA and PAI-2, were also detected by immunofluorescence studies. Thus human glomerular mesangial cells synthesize and secrete t-PA and PAI-1 in vitro. PAI-1 is produced in excess, therefore t-PA is only found in the form of a complex with PAI-1

    Dynamic Shear Modulus and Damping Ratio Predicted by a Unified 3-D Critical State Bounding Surface Plasticity Model

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    A unified 3-d critical state bounding surface plasticity model (gUTS) has been developed which is able to provide realistic simulations of the behavior of clays, silts and sands both in drained and undrained conditions over a wide range of monotonic and complex cyclic paths. A strong feature of this model is its ability to treat loose and dense states of the same material with a single set of material constants. The link between the two states is made by introducing an apparent normal consolidation line for sands and adopting a volumetric plastic strain hardening/softening model (similar to the critical state models for clays). This and other features enable the model to degenerate to simpler forms including the classic modified Cam-Clay formulation. To date, simulations have concentrated on the medium to high strain range (10-3 to 10-1). To address a wider strain range, this paper reports on a new series of simulations for sand in the range 10-6 to 10-
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