28 research outputs found

    On bounds for the fisher-rao distance between multivariate normal distributions

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOInformation geometry is approached here by considering the statistical model of multivariate normal distributions as a Riemannian manifold with the natural metric provided by the Fisher information matrix. Explicit forms for the Fisher-Rao distance associated to this metric and for the geodesics of general distribution models are usually very hard to determine. In the case of general multivariate normal distributions lower and upper bounds have been derived. We approach here some of these bounds and introduce a new one discussing their tightness in specific cases.Information geometry is approached here by considering the statistical model of multivariate normal distributions as a Riemannian manifold with the natural metric provided by the Fisher information matrix. Explicit forms for the Fisher-Rao distance associated to this metric and for the geodesics of general distribution models are usually very hard to determine. In the case of general multivariate normal distributions lower and upper bounds have been derived. We approach here some of these bounds and introduce a new one discussing their tightness in specific cases.1641313320FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2013/25977-7312926/2013-

    Antioxidant Activity And Hplc-dad Profile Of Moquiniastrum Polymorphum Subsp Floccosum (asteraceae)

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The antioxidant activity from Moquiniastrum polymorphum subsp. floccosum trunk bark was investigated by using 2,2-dipheny1-1-picrylhydrazyl and oxygen radical absorbance capacity-fluorescein assays, and the total phenolic content was estimated by Folin-Ciocalteau method. The ethanol extract and its fractions obtained by partition with solvents showed variable antioxidant activity. Ethyl acetate fraction exhibited the highest content of phenolic compounds (4.90 mg gallic acid equivalent/kg), as well as the antioxidant activity in both assays. Butanol fraction also showed significant antioxidant activity. HPLC analysis led to the identification of caffeic and chlorogenic acids together with caffeoyl quinic derivatives in ethyl acetate and butanol fractions, which are probably responsible for the observed activity.361200204Fundacao Araucaria [15288/2008]FAPESPFAEPEX-UnicampCAPESCNPqFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Análise multivariada de atributos pedológicos e fitossociológicos aplicada na caracterização de ambientes de cerrado no norte de Minas Gerais Multivariate analysis of pedological and phytosociogical attributes applied to characterization of cerrado environments in north of Minas Gerais State, Brazil

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    O Cerrado é uma das principais regiões de expansão agropecuária do país, entretanto a fragilidade dos seus ecossistemas restringe a capacidade de suporte a muitas das atividades agrícolas e compromete a preservação da sua biodiversidade. O objetivo deste estudo foi definir padrões locais de características edáficas e vegetacionais, em uma sub-bacia em Rio Pardo de Minas (MG), como base para o planejamento local de uso sustentável. Para tal, foram utilizadas técnicas de levantamento fitossociológico e de solos associadas à análise estatística multivariada, dendrograma e análise de componentes principais, de forma a correlacionar distribuição espacial de grupos de espécies e atributos edáficos. Os resultados indicaram a ordenação dos ambientes em dois grupos, em função da natureza dos materiais de origem: arenítico-quartzítico e sedimentos argilo-arenosos e argilosos. A seleção de variáveis pela análise multivariada foi capaz de discriminar os ambientes representados no levantamento fitossociológico. Os padrões identificados pelos agricultores corresponderam, em geral, às variações nos parâmetros florísticos e fitossociológicos e aos atributos edáficos, entre estes a densidade absoluta, a área basal e o índice de diversidade; as frações granulométricas foram determinantes na diferenciação dos ambientes.<br>The Cerrado is one of the main Brazilian expanding regions for agriculture, but the fragility of its ecosystems limits the support capacity for agriculture activities, jeopardizing the preservation of its biodiversity. The objective of this study was to define local patterns of edaphic and vegetation characteristics, of a small watershed in Rio Pardo de Minas municipality (Minas Gerais State, Brazil), as the basis for the sustainable planning for local usage. For such, techniques of phytosociological survey and soils were applied and associated to multivariate statistical procedures, dendrogram and PCA, in order to correlate the spatial distribution of groups of species with soil attributes. The results showed the classification of the environments into two groups, based on the nature of parent materials: arenitic-quartzitic and sandy-clayey and clayey sediments. The selection of variables using the multivariate analysis was able to discriminate the environments represented in the phytosociological plots. The patterns identified by the local farmers corresponded, in general, to the variations in the floristic and phytosociological parameters and edaphic attributes. The absolute density, basal area, Shannon index and the granulometric fractions were the determinant parameters in the differentiation of the environments
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