126 research outputs found

    Decision region approximation by polynomials or neural networks

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    We give degree of approximation results for decision regions which are defined by polynomial and neural network parametrizations. The volume of the misclassified region is used to measure the approximation error, and results for the degree of L1 approximation of functions are used. For polynomial parametrizations, we show that the degree of approximation is at least 1, whereas for neural network parametrizations we prove the slightly weaker result that the degree of approximation is at least r, where r can be any number in the open interval (0, 1)

    An NMR structural study of nickel-substituted rubredoxin

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    J Biol Inorg Chem (2010) 15:409–420 DOI 10.1007/s00775-009-0613-6The Ni(II) and Zn(II) derivatives of Desulfovibrio vulgaris rubredoxin (DvRd) have been studied by NMR spectroscopy to probe the structure at the metal centre. The βCH2 proton pairs from the cysteines that bind the Ni(II) atom have been identified using 1D nuclear Overhauser enhancement (NOE) difference spectra and sequence specifically assigned via NOE correlations to neighbouring protons and by comparison with the published X-ray crystal structure of a Ni(II) derivative of Clostridium pasteurianum rubredoxin. The solution structures of DvRd(Zn) and DvRd(Ni) have been determined and the paramagnetic form refined using pseudocontact shifts. The determination of the magnetic susceptibility anisotropy tensor allowed the contact and pseudocontact contributions to the observed chemical shifts to be obtained. Analysis of the pseudocontact and contact chemical shifts of the cysteine Hβ protons and backbone protons close to the metal centre allowed conclusions to be drawn as to the geometry and hydrogen-bonding pattern at the metal binding site. The importance of NH–S hydrogen bonds at the metal centre for the delocalization of electron spin density is confirmed for rubredoxins and can be extrapolated to metal centres in Cu proteins: amicyanin, plastocyanin, stellacyanin, azurin and pseudoazurin

    The Yeast PNC1 Longevity Gene Is Up-Regulated by mRNA Mistranslation

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    Translation fidelity is critical for protein synthesis and to ensure correct cell functioning. Mutations in the protein synthesis machinery or environmental factors that increase synthesis of mistranslated proteins result in cell death and degeneration and are associated with neurodegenerative diseases, cancer and with an increasing number of mitochondrial disorders. Remarkably, mRNA mistranslation plays critical roles in the evolution of the genetic code, can be beneficial under stress conditions in yeast and in Escherichia coli and is an important source of peptides for MHC class I complex in dendritic cells. Despite this, its biology has been overlooked over the years due to technical difficulties in its detection and quantification. In order to shed new light on the biological relevance of mistranslation we have generated codon misreading in Saccharomyces cerevisiae using drugs and tRNA engineering methodologies. Surprisingly, such mistranslation up-regulated the longevity gene PNC1. Similar results were also obtained in cells grown in the presence of amino acid analogues that promote protein misfolding. The overall data showed that PNC1 is a biomarker of mRNA mistranslation and protein misfolding and that PNC1-GFP fusions can be used to monitor these two important biological phenomena in vivo in an easy manner, thus opening new avenues to understand their biological relevance

    Características de programas de atividade física na atenção básica de saúde do Brasil

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    The aim of this study was to describe the characteristics of programs that promote physical activity in the public primary care system by region of Brazil, subject to the presence or absence of multidisciplinary primary care teams (NASF). We conducted a cross sectional and population-based telephone survey of the health unit coordinators from 1,251 health care units. Coordinators were asked about the presence and characteristics of physical activity programs. Four out of ten health units reported having a physical activity intervention program, the most common involving walking groups. Most of the activities were performed in the morning, once or twice a week, and in sessions of 30 minutes or more. Physical education professionals were primarily responsible for directing the activities. Interventions occurred in the health unit itself or in adjacent community spaces. In general, these characteristics were similar between units with or without NASF, but varied substantially across regions. These findings will guide future physical activity policies and programs within primary care in Brazil.El objetivo fue describir las características de los programas de actividad física en atención primaria, de acuerdo con el Centro de Apoyo a la Salud de la Familia (NASF) y las regiones de Brasil. Se realizó una encuesta transversal telefónica con 1.251 coordinadores de las unidades de salud. Se preguntó a los coordinadores acerca de la presencia y características de intervenciones de actividad física en funcionamiento. Cuatro de cada diez centros de salud reportaron tener una intervención de actividad física, especialmente, grupos de paseo. La mayor parte de las actividades se llevan a cabo por la mañana una vez o dos veces por semana con sesiones de 30 minutos o más. Los profesores de educación física son los principales responsables de la supervisión de las actividades. Los programas se llevan a cabo en la clínica o en otros espacios públicos. Estas características fueron similares en unidades con o sin NASF y mostraron una variación regional en su prevalencia. Estas características permitirán enfocar próximas acciones para promover la actividad física dentro de la atención primaria de salud.O objetivo foi descrever as características dos programas de atividade física na atenção básica de saúde de acordo com a presença de Núcleo de Apoio à Saúde da Família (NASF) no município e por regiões do Brasil. Foi realizado um estudo transversal por inquérito telefônico com 1.251 coordenadores de unidades de saúde. Foi aplicado um questionário sobre presença de intervenções com atividade física e suas características de funcionamento. Quatro em cada dez unidades de saúde relataram ter uma intervenção com atividade física, especialmente grupos de caminhada. A maior parte da atividade é realizada na manhã uma vez ou duas vezes por semana, com sessões de 30 minutos ou mais. Profissionais de educação física são os principais responsáveis por supervisionar as atividades. Os programas ocorrem na unidade de saúde ou outros espaços comunitários. Estas características, de modo geral, foram semelhantes entre unidades com ou sem NASF no município e apresentaram variação entre as regiões. Os resultados desse estudo irão permitir melhor direcionamento das próximas ações de promoção de atividade física na atenção básica de saúde.Universidade Federal de São Carlos Departamento de GerontologiaUniversidade Estadual Paulista Núcleo de Atividade Física, Esporte e SaúdeUniversidade Federal de Pelotas Grupo de Estudos em Epidemiologia da Atividade FísicaUniversidade Federal de São Paulo (UNIFESP)Centers for Disease Control and Prevention National Center for Chronic Disease Prevention and Health PromotionWashington University in St. Louis George Warren Brown School of Social WorkUniversidade de São Paulo Escola de Artes, Ciências e HumanidadesHospital Israelita Albert EinsteinMinistério da SaúdeEmory University Rollins School of Public HealthUNIFESPSciEL

    Prevalência de programas de promoção da saúde em unidades básicas de saúde no Brasil

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    OBJECTIVE Assessment of prevalence of health promotion programs in primary health care units within Brazil’s health system. METHODS We conducted a cross-sectional descriptive study based on telephone interviews with managers of primary care units. Of a total 42,486 primary health care units listed in the Brazilian Unified Health System directory, 1,600 were randomly selected. Care units from all five Brazilian macroregions were selected proportionally to the number of units in each region. We examined whether any of the following five different types of health promotion programs was available: physical activity; smoking cessation; cessation of alcohol and illicit drug use; healthy eating; and healthy environment. Information was collected on the kinds of activities offered and the status of implementation of the Family Health Strategy at the units. RESULTS Most units (62.0%) reported having in place three health promotion programs or more and only 3.0% reported having none. Healthy environment (77.0%) and healthy eating (72.0%) programs were the most widely available; smoking and alcohol use cessation were reported in 54.0% and 42.0% of the units. Physical activity programs were offered in less than 40.0% of the units and their availability varied greatly nationwide, from 51.0% in the Southeast to as low as 21.0% in the North. The Family Health Strategy was implemented in most units (61.0%); however, they did not offer more health promotion programs than others did. CONCLUSIONS Our study showed that most primary care units have in place health promotion programs. Public policies are needed to strengthen primary care services and improve training of health providers to meet the goals of the agenda for health promotion in Brazil.OBJETIVO Estimar a prevalência de programas de promoção da saúde nas unidades básicas de saúde no Brasil. MÉTODOS Estudo transversal descritivo realizado por meio de entrevistas telefônicas com coordenadores de unidades básicas de saúde. Do total de 42.486 unidades básicas de saúde cadastradas pelo Ministério da Saúde, 1.600 foram aleatoriamente selecionadas. As unidades foram amostradas nas cinco regiões do País de acordo com a proporção de unidades em cada região. Foi analisada a presença ou não de cinco programas de promoção da saúde: promoção de atividade física, cessação de tabagismo, cessação de uso de álcool e drogas ilícitas, alimentação saudável e ambiente saudável. Foram coletados dados sobre o tipo de ações desenvolvidas nos programas e a presença ou não da Estratégia de Saúde da Família na unidade. RESULTADOS A maioria das unidades básicas de saúde (62,0%) referiu ter pelo menos três programas de promoção da saúde e apenas 3,0% não tinha nenhum. A promoção do ambiente saudável e da alimentação saudável foram os programas mais prevalentes (77,0% e 72,0%, respectivamente), enquanto o controle do tabaco e do álcool foram referidos em 54,0% e 42,0% das unidades de saúde, respectivamente. A promoção de atividade física foi referida em menos de 40,0% das unidades e teve grande variação regional, com prevalência de 51,0% nas unidades do Sudeste e apenas 21,0% nas do Norte. A maioria das unidades de saúde (61,0%) oferecia Estratégia de Saúde da Família, porém não foi verificada maior prevalência de programas de promoção da saúde nessas unidades em relação às outras. CONCLUSÕES Este estudo mostrou que programas de promoção da saúde estão presentes na maioria das unidades básicas de saúde. Políticas públicas devem fortalecer a infraestrutura das unidades básicas de saúde e melhorar a capacitação dos trabalhadores de saúde para executar adequadamente a agenda de promoção de saúde do governo brasileiro

    Measurement of the Longitudinal Spin Transfer to Lambda and Anti-Lambda Hyperons in Polarised Muon DIS

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    The longitudinal polarisation transfer from muons to lambda and anti-lambda hyperons, D_LL, has been studied in deep inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to lambda and anti-lambda produced in the current fragmentation region exhibit different behaviours as a function of x and xF . The measured x and xF dependences of D^lambda_LL are compatible with zero, while D^anti-lambda_LL tends to increase with xF, reaching values of 0.4 - 0.5. The resulting average values are D^lambda_LL = -0.012 +- 0.047 +- 0.024 and D^anti-lambda_LL = 0.249 +- 0.056 +- 0.049. These results are discussed in the frame of recent model calculations.Comment: 13 pages, 7 figure

    A structured overview of simultaneous component based data integration

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    <p>Abstract</p> <p>Background</p> <p>Data integration is currently one of the main challenges in the biomedical sciences. Often different pieces of information are gathered on the same set of entities (e.g., tissues, culture samples, biomolecules) with the different pieces stemming, for example, from different measurement techniques. This implies that more and more data appear that consist of two or more data arrays that have a shared mode. An integrative analysis of such coupled data should be based on a simultaneous analysis of all data arrays. In this respect, the family of simultaneous component methods (e.g., SUM-PCA, unrestricted PCovR, MFA, STATIS, and SCA-P) is a natural choice. Yet, different simultaneous component methods may lead to quite different results.</p> <p>Results</p> <p>We offer a structured overview of simultaneous component methods that frames them in a principal components setting such that both the common core of the methods and the specific elements with regard to which they differ are highlighted. An overview of principles is given that may guide the data analyst in choosing an appropriate simultaneous component method. Several theoretical and practical issues are illustrated with an empirical example on metabolomics data for <it>Escherichia coli </it>as obtained with different analytical chemical measurement methods.</p> <p>Conclusion</p> <p>Of the aspects in which the simultaneous component methods differ, pre-processing and weighting are consequential. Especially, the type of weighting of the different matrices is essential for simultaneous component analysis. These types are shown to be linked to different specifications of the idea of a fair integration of the different coupled arrays.</p
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