419 research outputs found

    Multilevel Bayesian Deep Neural Networks

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    In this article we consider Bayesian inference associated to deep neural networks (DNNs) and in particular, trace-class neural network (TNN) priors which were proposed by Sell et al. [39]. Such priors were developed as more robust alternatives to classical architectures in the context of inference problems. For this work we develop multilevel Monte Carlo (MLMC) methods for such models. MLMC is a popular variance reduction technique, with particular applications in Bayesian statistics and uncertainty quantification. We show how a particular advanced MLMC method that was introduced in [4] can be applied to Bayesian inference from DNNs and establish mathematically, that the computational cost to achieve a particular mean square error, associated to posterior expectation computation, can be reduced by several orders, versus more conventional techniques. To verify such results we provide numerous numerical experiments on model problems arising in machine learning. These include Bayesian regression, as well as Bayesian classification and reinforcement learning

    Adapt On-the-Go: Behavior Modulation for Single-Life Robot Deployment

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    To succeed in the real world, robots must cope with situations that differ from those seen during training. We study the problem of adapting on-the-fly to such novel scenarios during deployment, by drawing upon a diverse repertoire of previously learned behaviors. Our approach, RObust Autonomous Modulation (ROAM), introduces a mechanism based on the perceived value of pre-trained behaviors to select and adapt pre-trained behaviors to the situation at hand. Crucially, this adaptation process all happens within a single episode at test time, without any human supervision. We provide theoretical analysis of our selection mechanism and demonstrate that ROAM enables a robot to adapt rapidly to changes in dynamics both in simulation and on a real Go1 quadruped, even successfully moving forward with roller skates on its feet. Our approach adapts over 2x as efficiently compared to existing methods when facing a variety of out-of-distribution situations during deployment by effectively choosing and adapting relevant behaviors on-the-fly.Comment: 19 pages, 6 figure

    MEDIDA PROVISÓRIA Nº 948 DE 8 DE ABRIL DE 2020 E OS IMPACTOS SOBRE OS DIREITOS SOCIAIS E ECONÔMICOS NAS RELAÇÕES DE CONSUMO

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    O presente trabalho tratou do tema da Medida Provisória nº 948, de 8 de abril de 2020, com foco nos impactos que sua edição causou nos direitos sociais e nas relações de consumo. O objetivo central do trabalho foi responder as perguntas: “quais consequências a Medida Provisória em questão trouxe para os direitos dos consumidores? Como harmonizar e equilibrar as relações de consumo em meio a uma pandemia que provocou uma grave crise econômica mundial?”. Adotou-se como metodologia de pesquisa o método de abordagem indutivo e o método de procedimento de análise de jurisprudência e análise bibliográfica. Os objetivos específicos do trabalho foram: compreender a Medida Provisória a partir de premissas constitucionais; analisar o impacto do referido ato normativo nos direitos sociais e econômicos dos consumidores e realizar a análise crítica da medida editad

    MEDIDA PROVISÓRIA Nº 948 DE 8 DE ABRIL DE 2020 E OS IMPACTOS SOBRE OS DIREITOS SOCIAIS E ECONÔMICOS NAS RELAÇÕES DE CONSUMO

    Get PDF
    O presente trabalho tratou do tema da Medida Provisória nº 948, de 8 de abril de 2020, com foco nos impactos que sua edição causou nos direitos sociais e nas relações de consumo. O objetivo central do trabalho foi responder as perguntas: “quais consequências a Medida Provisória em questão trouxe para os direitos dos consumidores? Como harmonizar e equilibrar as relações de consumo em meio a uma pandemia que provocou uma grave crise econômica mundial?”. Adotou-se como metodologia de pesquisa o método de abordagem indutivo e o método de procedimento de análise de jurisprudência e análise bibliográfica. Os objetivos específicos do trabalho foram: compreender a Medida Provisória a partir de premissas constitucionais; analisar o impacto do referido ato normativo nos direitos sociais e econômicos dos consumidores e realizar a análise crítica da medida editad

    Adherence to cervical and breast cancer programs is crucial to improving screening performance

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    Publicado onlineINTRODUCTION: Cervical and breast cancer are the most common malignancies among women worldwide. Effective screening can facilitate early detection and dramatically reduce mortality rates. The interface between those screening patients and patients most needing screening is complex, and women in remote areas of rural counties face additional barriers that limit the effectiveness of cancer prevention programs. This study compared various methods to improve compliance with mass screening for breast and cervical cancer among women in a remote, rural region of Brazil. METHODS: In 2003, a mobile unit was used to perform 10,156 mammograms and Papanicolaou smear tests for women living in the Barretos County region of São Paulo state, Brazil (consisting of 19 neighbouring cities). To reach the women, the following community outreach strategies were used: distribution of flyers and pamphlets; media broadcasts (via radio and car loudspeakers); and community healthcare agents (CHCAs) making home visits. RESULTS: The most useful intervention appeared to be the home visits by healthcare agents or CHCAs. These agents of the Family Health Programme of the Brazilian Ministry of Health reached an average of 45.6% of those screened, with radio advertisements reaching a further 11.9%. The great majority of the screened women were illiterate or had elementary level schooling (80.9%) and were of 'poor' or 'very poor' socioeconomic class (67.2%). CONCLUSIONS: Use of a mobile screening unit is a useful strategy in developing countries where local health systems have inadequate facilities for cancer screening in underserved populations. A multimodal approach to community outreach strategies, especially using CHCAs and radio advertisements, can improve the uptake of mass screening in low-income, low-educational background female populations

    Test of Factorization Hypothesis from Exclusive Non-leptonic B decays

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    We investigate the possibility of testing factorization hypothesis in non-leptonic exclusive decays of B-meson. In particular, we considered the non factorizable \bar{B^0} -> D^{(*)+} D_s^{(*)-} modes and \bar{B^0} -> D^{(*)+} (\pi^-, \rho^-) known as well-factorizable modes. By taking the ratios BR(\bar{B^0}-> D^{(*)+}D_s^{(*)-})/BR(\bar{B^0}-> D^{(*)+}(\pi^-,\rho^-)), we found that under the present theoretical and experimental uncertainties there's no evidence for the breakdown of factorization description to heavy-heavy decays of the B meson.Comment: 11 pages; submitted to PR

    Catalog of dessins d'enfants with \le 4 edges

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    In this work all the dessins d'enfant with no more than 4 edges are listed and their Belyi pairs are computed. In order to enumerate all dessins the technique of matrix model computations was used. The total number of dessins is 134; among them 77 are spherical, 53 of genus 1 and 4 of genus 2. The orders of automorphism groups of all the dessins are also found. Dessins are listed by the number of edges. Dessins with the same number of edges are ordered lexicographically by their lists of 0-valencies. The corresponding matrix model for any list of 0-valencies is given and computed. Complex matrix models for dessins with 1 -- 3 edges are used. For the dessins with 4 edges we use Hermitian matrix model, correlators for which are computed in [1].Comment: 64 pages, 134 figure

    Foreword

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    Lattice Calculation of Heavy-Light Decay Constants with Two Flavors of Dynamical Quarks

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    We present results for fBf_B, fBsf_{B_s}, fDf_D, fDsf_{D_s} and their ratios in the presence of two flavors of light sea quarks (Nf=2N_f=2). We use Wilson light valence quarks and Wilson and static heavy valence quarks; the sea quarks are simulated with staggered fermions. Additional quenched simulations with nonperturbatively improved clover fermions allow us to improve our control of the continuum extrapolation. For our central values the masses of the sea quarks are not extrapolated to the physical uu, dd masses; that is, the central values are "partially quenched." A calculation using "fat-link clover" valence fermions is also discussed but is not included in our final results. We find, for example, fB=190(7)(17+24)(2+11)(0+8)f_B = 190 (7) (^{+24}_{-17}) (^{+11}_{-2}) (^{+8}_{-0}) MeV, fBs/fB=1.16(1)(2)(2)(0+4)f_{B_s}/f_B = 1.16 (1) (2) (2) (^{+4}_{-0}), fDs=241(5)(26+27)(4+9)(0+5)f_{D_s} = 241 (5) (^{+27}_{-26}) (^{+9}_{-4}) (^{+5}_{-0}) MeV, and fB/fDs=0.79(2)(4+5)(3)(0+5)f_{B}/f_{D_s} = 0.79 (2) (^{+5}_{-4}) (3) (^{+5}_{-0}), where in each case the first error is statistical and the remaining three are systematic: the error within the partially quenched Nf=2N_f=2 approximation, the error due to the missing strange sea quark and to partial quenching, and an estimate of the effects of chiral logarithms at small quark mass. The last error, though quite significant in decay constant ratios, appears to be smaller than has been recently suggested by Kronfeld and Ryan, and Yamada. We emphasize, however, that as in other lattice computations to date, the lattice u,du,d quark masses are not very light and chiral log effects may not be fully under control.Comment: Revised version includes an attempt to estimate the effects of chiral logarithms at small quark mass; central values are unchanged but one more systematic error has been added. Sections III E and V D are completely new; some changes for clarity have also been made elsewhere. 82 pages; 32 figure

    Prior exercise training and experimental myocardial infarction: A systematic review and meta-analysis

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    Exercising prior to experimental infarction may have beneficial effects on the heart. The objective of this study was to analyze studies on animals that had exercised prior to myocardial infarction and to examine any benefits through a systematic review and meta-analysis. The databases MEDLINE, Google Scholar, and Cochrane were consulted. We analyzed articles published between January 1978 and November 2018. From a total of 858 articles, 13 manuscripts were selected in this review. When animals exercised before experimental infarction, there was a reduction in mortality, a reduction in infarct size, improvements in cardiac function, and a better molecular balance between genes and proteins that exhibit cardiac protective effects. Analyzing heart weight/body weight, we observed the following results - Mean difference 95% CI - -0.02 [-0.61,0.57]. Metaanalysis of the infarct size (% of the left ventricle) revealed a statistically significant decrease in the size of the infarction in animals that exercised before myocardial infarction, in comparison with the sedentary animals -5.05 [-7.68, -2.40]. Analysis of the ejection fraction, measured by echo (%), revealed that animals that exercised before myocardial infarction exhibited higher and statistically significant measures, compared with sedentary animals 8.77 [3.87,13.66]. We conclude that exercise performed prior to experimental myocardial infarction confers cardiac benefits to animals
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