896 research outputs found

    Técnicas de imagens no estudo comparativo de ovários de diferentes espécies domésticas

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    Tese (doutorado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-graduação em Biologia Animal, 2014.Avanços na pesquisa básica em reprodução animal e nas biotécnicas reprodutivas dependem da perfeita visualização e monitoramento das estruturas ovarianas no desenvolvimento folicular. Assim, o primeiro capítulo desta tese traz uma revisão bibliográfica sobre as principais técnicas utilizadas no estudo e na visualização de estruturas ovarianas, com foco no potencial, na aplicabilidade e nas limitações de cada técnica. O segundo capítulo foi conduzido com um experimento que teve como objetivo comparar as estruturas internas visualizadas no ovário em diferentes espécies por tomografia computadorizada (TC). Foram utilizados ovários de rata, cadela, gata, vaca, porca, égua e jumenta. Os ovários foram escaneados com uso de microtomógrafo computadorizado, e a reconstrução das imagens deu origem a representações bi e tridimensionais dos ovários. As mesmas amostras foram posteriormente processadas para avaliação histológica e validação dos resultados obtidos pelo microTC. A TC possibilitou distinguir as regiões de córtex e medula, observar folículos antrais, identificar os ovócitos dentro deles, visualizar corpos lúteos, bem como a distribuição e morfologia dos vasos sanguíneos de médio e grande calibre, embora não tenha possibilitado a visualização de folículos pré-antrais. Esta técnica apresenta possibilidades para o estudo das estruturas internas do ovário. O terceiro capítulo consiste em uma revisão de literatura que foi motivada pela percepção de que informações sobre a estrutura e ultraestrutura ovariana de diferentes espécies encontram-se dispersas e desassociadas na literatura. Abordando sete espécies domésticas, foram consideradas as principais diferenças na presença e distribuição das organelas citoplasmáticas em ovócitos e células da granulosa de folículos pré-antrais e antrais. Verificou-se que o padrão ultraestrutural de folículos e ovócitos varia entre espécies domésticas bem como entre as fases do desenvolvimento folicular. Este tipo de conhecimento permite melhorias na compreensão anatômica e fisiológica do ovário, e pode subsidiar avanços em diversas linhas de pesquisa, como na melhoria das biotecnologias reprodutivas e no auxílio da compreensão de danos e pontos limitantes da manipulação in vitro de ovócitos em diferentes espécies. ______________________________________________________________________________ ABSTRACTMonitoring ovarian structures during follicular development may enable great advances in reproductive biotechnologies and animal reproduction. In this sense, this thesis was divided in three chapters, aiming to empower the understanding of diagnostic imaging, the characterization of ovarian structures and the comparison between domestic species. The first chapter of the thesis is a bibliographic revision considering the main techniques that are useful to visualize the ovarian structures. We focused on the potential, applicability and general limitations of each technique. The second chapter consists of an experiment, undertaken to compare the internal structures of the ovary using computerized microtomography. We compared the ovaries of rats, bitches, quees, cows, mares, sows and female donkey and carried out the reconstruction of the tomographic images to originate two and three dimensional representations. After scanning, the same samples were prepared for histologic evaluation, used in this research as validation criteria for ovary research based on computerized microtomography. Microtomography enabled to distinguish the regions of the cortex and medulla, to identify oocytes, corpus luteum and to visualize the morphology and distribution of medium caliber blood vessels. However, it didn’t enable the visualization of pre antral follicles. The third chapter of the thesis is a bibliographic revision motivated by the fact that information comparing the ovarian ultrastructure between species is scarce. We emphasized major differences in seven domestic species, considering the presence and distribution of cytoplasmic organelles in oocytes, granulosa cells, pre antral and antral follicles. It was observed that the ultrastructure of follicles and oocytes vary between species and between the stages of follicular development. This research subsidizes advanced comprehension of the anatomy and physiology of the ovary in different species. It may enable the understanding of several limitations points related to in vitro manipulation of oocytes and, therefore, generate future adjustments in reproductive technologies

    Evaluation of ovarian structures using computerized microtomography

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    Visualization and clear understanding of the ovarian structures are important in determining the stage of oestrus, helping to diagnose several pathologies and supporting advances in reproductive technologies. In this research, computerized microtomography (microCT) was used to explore and characterize the ovarian structure of seven mammalian species. Ovaries of rats, female dog, queens, cows, mares, sows and a female donkey were used. After microCT scanning, the same samples were prepared for histologic evaluation, used here as a validation criterion. It was possible to distinguish regions of the cortex and medulla, visualize the morphology and distribution of blood vessels, clearly observe corpus luteum and antral follicles, and visualize oocytes inside some antral follicles. This is the first report using microCT to explore and compare ovarian structures in several domestic mammals. MicroCT revealed great potential for the evaluation of ovarian structures. This research open prospects for the use of computerized tomography (CT) as a non-invasive approach to studying ovarian structures in live animals, which may be especially attractive for scientific study of development of ovarian structures and/or ovarian pathologies in small animals’ models

    Polymorphism of exon 20 of the leptin receptor gene and serum leptin concentrations of Nellore heifers raised on pasture

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    The physiological changes that occur at puberty in heifers are objectives of study in order to better understand this phenomenon and to identify alternatives to achieve greater sexual precocity. Among the most important factors that influence puberty the leptin hormone and its receptor can be highlighted, as they are factors that perform communication between the nutritional status and the reproductive axis, and its participation in reproductive physiology is not fully understood. Therefore, the aim of this study was to determine the serum profile of the leptin hormone, to identify polymorphisms at exon 20 of the leptin receptor and associate them with the occurrence of puberty in heifers raised on pasture. We followed 56 heifers for 17 months and carried out the progesterone assay for determining the puberty occurrence, leptin dosage and sequencing of the leptin receptor gene for identifying the occurrence of SNP polymorphisms. After identifying the manifestation of puberty in 37 heifers and the association of serum leptin and the occurrence of SNPs with the occurrence of this physiological phenomenon, no correlation was found between variables with the onset of puberty.The physiological changes that occur at puberty in heifers are objectives of study in order to better understand this phenomenon and to identify alternatives to achieve greater sexual precocity. Among the most important factors that influence puberty the leptin hormone and its receptor can be highlighted, as they are factors that perform communication between the nutritional status and the reproductive axis, and its participation in reproductive physiology is not fully understood. Therefore, the aim of this study was to determine the serum profile of the leptin hormone, to identify polymorphisms at exon 20 of the leptin receptor and associate them with the occurrence of puberty in heifers raised on pasture. We followed 56 heifers for 14 months and carried out the progesterone assay for determining the puberty occurrence, leptin dosage and sequencing of the leptin receptor gene for identifying the occurrence of SNP polymorphisms. Concentration of leptin was compared between the animals puberty with animals not puberty and the hormone of the animals puberty in the pre-pubertal and pubertal periods. After the identification of the polymorphism, the possible interactions of the mutation occurrence in the leptin receptor gene with the leptin concentrations and the puberty were analyzed. After analyzing, no observed correlation between the occurrence of the mutation in the leptin T945M receptor gene and leptin plasma concentrations and the puberty in heifers raised on pasture

    COMPOSITION, STRUCTURE, ISOLATION AND ANTIOXIDANT ACTIVITY OF SECONDARY METABOLITES FROM BROWN ALGAE

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    Recently, the search for natural antioxidants for the creation of new drugs and/or drug enhancers has been growing. In this context, brown algae stand out for having in their extracts compounds with antioxidant activity such as fucoidans, phlorotannins, fucoxanthin, and laminaria. This review summarizes the main research into important metabolites found during the analysis of brown algae, as well as performing evaluation of antioxidant activity, both in vitro and in vivo, of bioactive compounds from brown seawee

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good
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