Gamma Models
Mostrando 25-36 de 243 artigos, teses e dissertações.
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25. Methodological approaches to planar and volumetric scintigraphic imaging of small volume targets with high spatial resolution and sensitivity
Single-photon emission computed tomography (SPECT) is a non-invasive imaging technique, which provides information reporting the functional states of tissues. SPECT imaging has been used as a diagnostic tool in several human disorders and can be used in animal models of diseases for physiopathological, genomic and drug discovery studies. However, most of the
Brazilian Journal of Medical and Biological Research. Publicado em: 2009-08
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26. Quantifying the Matter Inhomogeneities with Supernovae and Gamma-Ray Bursts / Quantificando as inomogeneidades da matéria com Supernovas e Gamma-Ray Bursts
In this dissertation we study how the effects of matter (baryonic and dark) inhomogeneities modify the distances thereby affecting the determination of cosmological parameters. The inhomogeneities are phenomenologically described by the clumpiness parameter alpha and quantified through the equation distance proposed by ZeldovichKantowskiDyer Roeder (ZKDR). F
Publicado em: 2009
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27. Modelos não-lineares de regressão : alguns aspectos de teoria assintótica
The main objective in this dissertation is to derive expressions for the second-order biases of the maximum likelihood estimators of the parameters of the Weibull generalized linear model (WGLM), which are useful to define corrected estimators. In order to reduce the bias of these estimators in finite sample sizes, the method of bias correction introduced by
Publicado em: 2009
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28. Finanças comportamentais: uma avaliação crítica da moderna teoria de finanças
Among the main commonly debated questions regarding finance, there is the validity of its most traditional theories premises, in special the rationality of economic agents. In this context, different studies have appeared with the intention of improving the theoretical dominant models, incorporating behavioral aspects never considered before. Such innovation
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/05/2008
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29. Utilização de técnicas bayesianas em modelos de regressão de Poisson para dados de contagem longitudinais e dados de contagem com medidas repetidas apresentando excesso de zeros
In medical and biological researches we often .nd count data. For longitudinal count data, usual Poisson regression models, assuming independence among observations, are not applicable because of the correlation of these measures. This work presents hierarchical Bayesian models considering random eects to analyze longitudinal count data. A Normal and a Gamma
Publicado em: 2008
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30. Improvement of Wald residual in generalized linear models / Melhoramento do resíduo de Wald em modelos lineares generalizados
The theory of generalized linear models is very used in statistics, not only for modeling data normally distributed, but in the modeling of data whose distribution belongs to the exponential family of distributions. Some examples are binomial, gamma and inverse Gaussian distribution, among others. After tting a model in order to check the adequacy of tting,
Publicado em: 2008
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31. Beta-binomial/gamma-Poisson regression models for repeated bivariate counts / Modelos Beta-Binomial/Poisson-Gama para contagens bivariadas repetidas
Em Lora e Singer (Statistics in Medicine, 2008), propusemos um modelo Beta- Binomial/Poisson p-variado para análise dos dados provenientes de um estudo que consistiu em contar o número de tentativas e acertos de um exercício manual com duração de um minuto realizado por doentes de Parkinson, antes e depois de um treinamento. O objetivo era verificar se
Publicado em: 2008
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32. Análise de sobrevivência do tomateiro a Phytophthora infestans / Analysis of the survival of the tomato plant Phytophthora infestans
Reburning caused by Phytophthora infestansis is characterized as an aggressive disease of great destructive impact, capable of limiting or even hindering the economic cultivation of the tomato plant under conditions of high humidity and low temperatures. In view of the problems reburning can cause to tomato plant crops, this work aimed to: 1) fit models to d
Publicado em: 2008
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33. Função de acoplamento t-Student assimetrica : modelagem de dependencia assimetrica / Skewed t-Student copula function : skewed dependence modelling
The Skewed t-Student distribution family, constructed upon the multivariate normal mixture distribution, known as mean-variance mixture, composed with the Inverse-Gamma distribution, has many desirable flexibility properties for many distribution asymmetry structures. These properties are explored by constructing copula functions with asymmetric dependence.
Publicado em: 2008
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34. Desenvolvimento de uma interface grÃfica de usuÃrio para modelos computacionais de exposiÃÃo externa / DEVELOPMENT OF A GRAPHIC USER INTERFACE FOR EXTERNAL EXPOSURE COMPUTATIONAL MODELS
To evaluate the absorbed dose by the patient, in a series of exams, it is necessary to accomplish simulations using an exposure computational model. Such models are fundamentally composed of a virtual representation of the human body (phantom) and a Monte Carlo code. There are several Monte Carlo codes available and also specific voxel phantoms for the two g
Publicado em: 2007
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35. A mitochondrial metazoan phylogeny / Uma filogenia mitocondrial de metazoários
Inferring the evolutive relations between the animal phyla has been a formidable challenge to Science. The animal phyla represent quite distinct baupläne (body architectures) and are, therefore, difficult to compare. At the same time, their fossil record converges mostly to the same period on the geological scale. The recent availability of molecular data h
Publicado em: 2007
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36. Study of conformational changes of macromolecules in solutions using X-ray scattering / Estudo de mudanças conformacionais de macromoleculas em solução usando espalhamento de raio-X
During the last decades, the study of conformational changes in biological macromolecules has been a great challenge for the scientists, and continues to be an important subject of biotechnological interest and protein engineering. The process of folding (unfolding) of protein molecules has been intensively studied, because this investigation can contribute
Publicado em: 2007