2,483 research outputs found
Caracterização de paredes tradicionais de tabique
Neste artigo discutem-se aspectos construtivos relacionados com as paredes divisórias tradicionais de tabique, de forma a contribuir para um conhecimento mais aprofundado sobre este tipo de elementos, que são parte integrante de um estilo de construção marcante no panorama do património construído português que imperou até inícios do século XX. Informação relativa aos materiais utilizados e às soluções construtivas adoptadas é fornecida e descrita. Simultaneamente, algumas propriedades físicas avaliadas também são apresentadas com a intenção de auxiliar processos de reabilitação e outros trabalhos de investigação que visem o estudo de soluções construtivas alternativas de paredes divisórias, tendo em conta que o tabique pode ser uma técnica construtiva sustentável, económica e versátil
Co-selection of the H63D mutation and the HLA-A29 allele: a new paradigm of linkage disequilibrium?
The major histocompatibility complex (MHC) shows a remarkable conservation of particular HLA antigens and haplotypes in linkage disequilibrium in most human populations, suggesting the existence of a convergent evolution. A recent example of such conservation is the association of particular HLA haplotypes with the HFE mutations. With the objective of exploring the significance of that association, the present paper offers an analysis of the linkage disequilibrium between HLA alleles or haplotypes and the HFE mutations in a Portuguese population. Allele and haplotype associations between HLA and HFE mutations were first reviewed in a population of 43 hemochromatosis families. The results confirmed the linkage disequilibrium of the HLA haplotype HLA-A3-B7 and the HLA-A29 allele, respectively, with the HFE mutations C282Y and H63D. In order to extend the study of the linkage disequilibrium between H63D and the HLA-A29-containing haplotypes in a normal, random population, an additional sample of 398 haplotypes was analyzed. The results reveal significant linkage disequilibrium between the H63D mutation and all HLA-A29-containing haplotypes, favoring the hypothesis of a co-selection of H63D and the HLA-A29 allele itself. An insight into the biological significance of this association is given by the finding of significantly higher CD8+ T-lymphocyte counts in subjects simultaneously carrying the H63D mutation and the HLA-A29 allele
Pareto Optimal Solutions for Stochastic Dynamic Programming Problems via Monte Carlo Simulation
A heuristic algorithm is proposed for a class of stochastic discrete-time continuous-variable dynamic programming problems submitted to non-Gaussian disturbances. Instead of using the expected values of the objective function, the randomness nature of the decision variables is kept along the process, while Pareto fronts weighted by all quantiles of the objective function are determined. Thus, decision makers are able to choose any quantile they wish. This new idea is carried out by using Monte Carlo simulations embedded in an approximate algorithm proposed to deterministic dynamic programming problems. The new method is tested in instances of the classical inventory control problem. The results obtained attest for the efficiency and efficacy of the algorithm in solving these important stochastic optimization problems
Adaptabilidade e estabilidade de carotenóides em cultivares de milho.
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Uso da realidade aumentada em auxílio à Educação
O crescente uso da Realidade Aumentada (RA) na Educação é um fato positivo. Assim, o objetivo desta pesquisa é buscar melhorar o processo de ensino-aprendizagem dos discentes. Acredita-se que a absorção do conteúdo se tornará mais fácil quando existir a possibilidade de visualização da informação que se pretende transmitir, por meio do uso de técnicas de visão computacional. A metodologia empregada no projeto foi constituída por uma consulta bibliográfica que ofereceu o suporte teórico necessário para a elaboração de uma aplicação RA para web, denominada RAINFOR. Observou-se inicialmente que os alunos se demonstraram motivados com a possibilidade de interatividade e com a facilidade de uso dessa ferramenta
Black Hole Thermodynamics and Two-Dimensional Dilaton Gravity Theory
We relate various black hole solutions in the near-horizon region to black
hole solutions in two-dimensional dilaton gravity theories in order to argue
that thermodynamics of black holes in D>=4 can be effectively described by
thermodynamics of black holes in two-dimensional dilaton gravity theories. We
show that the Bekenstein-Hawking entropies of single-charged dilatonic black
holes and dilatonic p-branes with an arbitrary dilaton coupling parameter in
arbitrary spacetime dimensions are exactly reproduced by the Bekenstein-Hawking
entropy of the two-dimensional black hole in the associated two-dimensional
dilaton gravity model. We comment that thermodynamics of non-extreme stringy
four-dimensional black hole with four charges and five-dimensional black hole
with three charges may be effectively described by thermodynamics of the black
hole solutions with constant dilaton field in two-dimensional dilaton gravity
theories.Comment: 15 pages, LaTeX, added reference
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