Papers by Victor Oliveira
The Brazilian Journal of Infectious Diseases, 2014
Simultaneous autoregressive (SAR) models have been extensively used for the analysis of spatial d... more Simultaneous autoregressive (SAR) models have been extensively used for the analysis of spatial data in diverse areas, such as demography, economy and geography. The most common approach for inference on these models has been maximum likelihood and the Bayesian approach has not been used or explored much. This work proposes default (automatic) Bayesian analyzes of SAR models. Two versions of Jeffreys prior, the independence Jeffreys and Jeffreys-rule priors, are derived for the parameters of SAR models and properties of the priors and resulting posterior distributions are obtained. Frequentist properties of inferences based on maximum likelihood are compared with those based on the Jeffreys priors and the uniform prior. As an application the SAR model is used to fit a dataset of homicide rates in 1980 for southern U.S. counties.
Computational Statistics Data Analysis, Oct 1, 2009
This work considers the problem of constructing prediction intervals in log-Gaussian random field... more This work considers the problem of constructing prediction intervals in log-Gaussian random fields. New prediction intervals are derived that are shorter than the standard prediction intervals of common use, where the reductions in length can be substantial in some ...
Materials Science Forum, 2003
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Este estudo teve como objetivo avaliar se existem variações significativas nos estilos cognitivos... more Este estudo teve como objetivo avaliar se existem variações significativas nos estilos cognitivos dos estudantes universitários em função da área de conhecimento, idade e gênero. O instrumento utilizado para identificar os Estilos Cognitivos especificamente os processos perceptivos Dependência e Independência de Campo foi o Group Embedded , teste das figuras ocultas empregado para identificar o estilo cognitivo dos estudantes na sua forma coletiva. Participaram da pesquisa 451 estudantes matriculados em cursos de duas diferentes áreas de formação acadêmica: Ciências Contábeis e Engenharia da Produção. Com a utilização da análise de variância (ANOVA), média e desvio padrão, foi possível verificar que há diferença significativa nos estilos cognitivos quando a população em estudo é agrupada por diferentes áreas de formação acadêmica. No curso de Engenharia há uma maior concentração de estudantes com estilo cognitivo independentes de campo do que entre os 2 cursos de Ciências Contábeis. A partir do reconhecimento dessas diferenças cognitivas, é possível aperfeiçoar o relacionamento entre os docentes e discentes, proporcionando, assim, maior efetividade e qualidade no processo ensino-aprendizagem.
Cancer, 2005
Renal medullary carcinoma is a rare tumor that is most common in young black men with sickle cell... more Renal medullary carcinoma is a rare tumor that is most common in young black men with sickle cell disease or trait. Patients often present with advanced disease at the time of diagnosis, and their prognosis is poor, even with aggressive therapy. The clinical and pathologic features of renal medullary carcinoma have been described in several articles, but reports describing the cytologic features are rare. In the current report, the authors describe the cytologic features of three cases of renal medullary carcinoma. The patients were young black men with sickle cell trait ages 20 years, 33 years, and 33 years. All three patients presented with hematuria, flank pain, and a renal mass. The cytologic specimens from all three patients showed primarily cohesive groups of cells with vacuolated cytoplasm that often displaced or indented the nuclei. The nuclei often had irregular membranes, coarse or vesicular chromatin, and prominent nucleoli. Both of the two patients who were tested with fluorescence in situ hybridization were negative for the bcr/abl rearrangement. Renal medullary carcinoma should be considered in the differential diagnosis of patients who present with hematuria or a renal mass, especially in young black men with sickle cell disease or trait. Cytologically, renal medullary carcinoma cells appear similar to the cells in high-grade carcinoma. Immunohistochemical studies can be helpful in distinguishing renal medullary carcinoma from other poorly differentiated kidney tumors, except for collecting duct carcinoma. The clinical findings are key to diagnosing renal medullary carcinoma.
Hydrometallurgy, Apr 1, 2010
The alkaline leaching kinetics of a zinc silicate ore assaying 34.1% Zn, 11.1% Fe and 22.9% SiO 2... more The alkaline leaching kinetics of a zinc silicate ore assaying 34.1% Zn, 11.1% Fe and 22.9% SiO 2 is studied in sodium hydroxide solutions. Speciation diagrams indicate zinc dissolution as [Zn(OH) 4 ] 2− and SEM analysis showed a progressive reduction in particle size during leaching which supports the shrinking particle model. The process is chemically controlled with an activation energy of 67.8 ± 9.0 kJ/mol and reaction order with respect to NaOH determined as 1.44 ± 0.46.
Http Dx Doi Org 10 1198 106186005x27518, 2012
This work develops a Bayesian approach to perform inference and prediction in Gaussian random fie... more This work develops a Bayesian approach to perform inference and prediction in Gaussian random fields based on spatial censored data. These type of data occur often in the earth sciences due either to limitations of the measuring device or particular features of the ...
Acta Medica Portuguesa, Oct 31, 2013
European Respiratory Journal, Sep 1, 2014
Hu Revista, Oct 25, 2010
O enfisema lobar congênito é uma malformação pulmonar rara, caraterizado por hiperinsuflação pulm... more O enfisema lobar congênito é uma malformação pulmonar rara, caraterizado por hiperinsuflação pulmonar, sendo o lobo superior esquerdo o mais acometido (43%). Os sintomas aparecem, mais frequentemente, nos primeiros seis meses de vida, com manifestações de dispnéia e cianose, sendo o diagnóstico clínico confirmado pela radiografia de tórax. Está associado a algumas malformações, principalmente cardíacas. A lobectomia é o tratamento de escolha nas crianças graves, apresentando resultados superiores ao tratamento clínico. Este trabalho relata o caso de um lactente que foi submetido a lobectomia e evoluiu com melhora importante do quadro clínico.
Volume 5: 19th Biennial Conference on Mechanical Vibration and Noise, Parts A, B, and C, 2003
Computational Biomechanics for Medicine, 2014
Parasitology Research, 2015
Ubiquitin-conjugating enzymes (Ub-E2) perform the second step of ubiquitination and, consequently... more Ubiquitin-conjugating enzymes (Ub-E2) perform the second step of ubiquitination and, consequently, are essential for regulating proteolysis and for modulating protein function, interactions and trafficking. Previously, our group demonstrated the crucial role of ubiquitination and the Ub-proteasome pathway during the Schistosoma mansoni life cycle. In the present investigation, we used a homology-based genome-wide bioinformatics approach to identify and molecularly characterise the Ub-E2 enzymes in S. mansoni. The putative functions were further investigated through molecular phylogenetic and expression profile analyses using cercariae, adult worms, eggs and mechanically transformed schistosomula (MTS) cultured in vitro for 3.5 h or 1 or 3 days. We identified, via in silico analysis, 17 Ub-E2 enzymes with conserved structural characteristics: the beta-sheet and the helix-2 form a central core bordered by helix-1 at one side and helix-3 and helix-4 at the other. The observed quantitative differences in the steady-state transcript levels between the cercariae and adult worms may contribute to the differential protein ubiquitination observed during the parasite's life cycle. This study is the first to identify and characterise the E2 ubiquitin conjugation family in S. mansoni and provides fundamental information regarding their molecular phylogenetics and developmental expression during intra-mammalian stages.
Proceedings of SPIE - The International Society for Optical Engineering, 2001
We produced a totally conservative finite-volume scheme for modeling of Al<SUB>2</SUB>... more We produced a totally conservative finite-volume scheme for modeling of Al<SUB>2</SUB>O<SUB>3</SUB>-TiC ceramics processing with excimer laser radiation. Evolution of a cylindrical TiC grain at the.
Polímeros, 2009
ABSTRACT Este trabalho descreve as sínteses de hidrogéis superabsorventes a base de acetato de ce... more ABSTRACT Este trabalho descreve as sínteses de hidrogéis superabsorventes a base de acetato de celulose (AC), com grau de substituição 2.5, reticulado com dianidrido 3, 3&#39;, 4, 4&#39; benzofenona tetracarboxílico (BTDA). As caracterizações das matérias primas foram realizadas por análises térmicas (TG/DTG) e espectroscopia na região do infravermelho (FTIR). O grau de substituição do acetato de celulose foi determinado por via úmida. A confirmação da reação de esterificação foi possível a partir da técnica de FTIR, espectroscopia UV-vis e análises térmicas (TG/DTG). A presença de poros no novo material foi analisada por microscopia eletrônica de varredura (MEV) e porosimetria (BET). A influência da concentração de dianidrido no meio reacional foi investigada, bem como a influência do aumento no grau de reticulação no comportamento térmico do material. Foram obtidas isotermas de absorção de água em diferentes temperaturas para os hidrogéis com diferentes graus de reticulação. Os coeficientes de difusão dos géis foram determinados, juntamente com a energia de ativação para o processo de inchamento usando a equação de Arrhenius. A entalpia de mistura do sistema gel-água foi determinada pela medida da quantidade máxima de água absorvida no equilíbrio a diferentes temperaturas, empregando a equação de Gibbs/Helmholtz.
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Papers by Victor Oliveira