2,610 research outputs found

    Hyperuricemia in Chronic Kidney Disease: a Role Yet To Be Explained

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    The role of uric acid as an independent risk factor for chronic kidney disease development and progression is still a matter of discussion. Several observational studies showed a positive association between hyperuricemia and the progression of kidney dysfunction, but others did not, which probably derived from different biases and studies insufficiencies. Moreover, the results from studies on patients in hemodialysis and peritoneal dialysis are even more controversial, with some evidence pointing towards a protective role of uric acid in hemodialysis patients, but not in peritoneal dialysis. In addition to most evidence suggesting a role of uric acid in chronic kidney disease pathogenesis and progression, pharmacological treatment of asymptomatic hyperuricemia is still not indicated, with no consensus on either the uric acid level at which treatment would be beneficial, or the target-level to achieve. There are several studies on the renal benefits of xanthine oxidase inhibitors allopurinol and febuxostat, with heterogeneous results. Most of them showed a renoprotective effect of both drugs, delaying renal disease progression. However, the different results found in other studies makes it difficult to draw definitive conclusions. Despite recent evidence pointing toward an important role of uric acid in the pathogenesis and progression of kidney disorders, and the benefits of its treatment, there are still several unanswered questions, and well-conducted studies are needed to make valid conclusions.info:eu-repo/semantics/publishedVersio

    Optical-force laws for guided light in linear media

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    CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPEMIG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAISCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORThe mechanical response of transparent materials to optical forces is a topic that concerns a wide range of fields, from the manipulation of biological material by optical tweezers to the design of nano-optomechanical systems. However, the fundamental aspects of such forces have always been surrounded by controversies, and several different formulations have been proposed. In this paper, we propose a general stress tensor formalism to put all optical forces in a consistent presentation that allows us to study how different predictions emerge, and use the specific case of light propagating as a superposition of guided modes in lossless dielectric waveguides as a physical example. We use this formalism to calculate optical forces for straight and curved waveguide sections and all possible excitation configurations for a given set of coupled eigenmodes, and then compare the results for each of the known proposed optical-force laws in a framework that permits distinguishing where there will be differences between the force laws proposed. The general formalism also allows us to show that proper use of the divergence theorem is crucial to account for all force terms, many of which vanish if the procedure most commonly used is applied for situations other than eigenmodes in straight waveguides in vacuum. Finally, it is known that discrepancies in the predicted forces arise from the incompleteness of each stress tensor with respect to the total-energy-momentum tensor of the system. A better understanding of how different stress tensors predict very different forces for certain waveguide geometries should open a pathway to identifying how to properly assemble the full tensor, as well as for experimental tests to confirm the predictions.100117CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPEMIG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAISCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPEMIG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAISCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORSem informaçãoSem informaçãoSem informaçã

    Genetic improvement of forest tree species.

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    Brazilian forestry sector is considered one of the most developed in the world, being the base for important industrial segments which use wood as raw material. Tree breeding has played an important role on improving the competitiveness of Brazilian forestry-based companies, especially for its positive reflexes on increasing adaptation, forestry productivity and wood quality. In spite of the importance of other forest trees for the economy, such as Schizolobium, Araucaria, Populus and Hevea, the main genera under genetic improvement in the country are Eucalyptus, Pinus, Acacia and Tectona. They are used by industries like pulp and paper, siderurgy, tannin, chips for exportation and lumber, constituting an important source of revenues for the Brazilian?s economy, besides their positive social and environmental impacts. This paper presents a generic approach to genetic improvement aspects of these four major genera currently undergoing breeding in Brazil.Especial issue

    Seleção recorrente recíproca entre populações sintéticas multi-espécies (SRR-PSME) de eucalipto.

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    Propõe-se estratégia de melhoramento para o eucalipto, que visa contemplar, em um mesmo indivíduo, características desejáveis presentes em diferentes espécies e, simultaneamente, capitalizar heterose para crescimento, advinda de vários pares de espécies, cujas combinações são sabidamente heteróticas. Baseia-se na obtenção de duas populações sintéticas multi-espécies e posterior seleção recorrente recíproca (SRR) entre essas. É denominada seleção recorrente recíproca entre populações sintéticas multi-espécies (SRR-PSME) e melhora os caracteres resistência à seca e às doenças, volume, densidade, rendimento e teor de lignina. São apresentadas opções para composição das populações sintéticas. A SRR-PSME é favorável também à aplicação da seleção genômica.Nota Científica

    Corymbia citriodora: estado da arte de pesquisas no Brasil.

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    Introdução; Área de ocorrência natural e descrição botânica; Importância econômica da espécie e utilizações; Caracterização da madeira; Doenças e insetos-praga; Aspectos silviculturais; Germoplasma e melhoramento genético; Melhoramento genético e caracteres de importância; Comercialização de sementes e cultivares; Hibridação interespecífica; Propagação vegetativa; Considerações finais; Referências.bitstream/item/94547/1/Doc.-255-Reis-Ainfo1.pd

    A Compact Sift-Based Strategy for Visual Information Retrieval in Large Image Databases

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    This paper applies the Standard Scale Invariant Feature Transform (S-SIFT) algorithm to accomplish the image descriptors of an eye region for a set of human eyes images from the UBIRIS database despite photometric transformations. The core assumption is that textured regions are locally planar and stationary. A descriptor with this type of invariance is sufficient to discern and describe a textured area regardless of the viewpoint and lighting in a perspective image, and it permits the identification of similar types of texture in a figure, such as an iris texture on an eye. It also enables to establish the correspondence between texture regions from distinct images acquired from different viewpoints (as, for example, two views of the front of a house), scales and/or subjected to linear transformations such as translation. Experiments have confirmed that the S-SIFT algorithm is a potent tool for a variety of problems in image identification

    Avaliação do efeito da combinação de pectina, gelatina e alginato de sódio sobre as características de gel de fruta estruturada a partir de "mix" de polpa de cajá e mamão, por meio da metodologia de superfície de resposta.

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    Este trabalho teve por objetivo estabelecer procedimento tecnológico para produção de fruta estruturada a partir de ?mix? de polpa de cajá e mamão, procurando unir as propriedades sensoriais de cada uma das frutas e potencializar as características funcionais do produto final. Avaliou-se o efeito da combinação de pectina, gelatina e alginato de sódio, via metodologia de superfície de resposta, nas características do gel de fruta. As polpas de mamão e cajá e os estruturados obtidos foram caracterizados com relação aos compostos funcionais, avaliando-se o teor de taninos e carotenóides totais, além das análises de composição centesimal, pH, acidez titulável, sólidos solúveis, açúcares, atividade de água, carboidratos e valor energético total. Os resultados obtidos através do planejamento experimental indicam que para o estruturado misto de cajá e mamão, somente o aumento da concentração de gelatina afeta a firmeza do produto final. Os estruturados de frutas desenvolvidos apresentaram boa aceitação sensorial para todos os atributos avaliados. Com relação à intenção de compra, 70% dos provadores responderam que provavelmente ou certamente, comprariam o estruturado misto de cajá e mamão se o encontrassem à venda
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