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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Trois essais sur la surliquidité bancaire dans la communauté économique et monétaire d'Afrique Centrale (CEMAC) / Three essays on bank overliquidity in the Economic and Monetary Community of Central Africa (CEMAC)

Beguy, Olivier 16 February 2012 (has links)
Cette thèse s’articule autour de trois essais consacrés à l’analyse de la surliquidité bancaire dans les pays de la CEMAC. Le premier essai a cherché à identifier les déterminants de la surliquidité des pays membres de la CEMAC sur la période de 1985 à 2002. L’estimation GMM utilisé a permis de montrer que la surliquidité en Afrique Centrale dérive à la fois du comportement de précaution des banques commerciales et des facteurs exogènes. La grande prudence des banques peut s’expliquer par l’expérience de la crise financière des années 1980, la restructuration du système bancaire, l’instabilité des dépôts et un contexte économique très risqué. L’embellie du cours du pétrole alimente les réserves excédentaires due à la faible capacité d’absorption des pays de la zone. Dans le deuxième essai, il a été question d’identifier les canaux de transmission les plus opérationnels en Afrique Centrale. La modélisation VAR a permis de montrer que le taux d’intérêt est le canal le plus faible. C’est précisément la carence d’un marché financier qui ne permet pas d’assurer le rôle de recyclage de la liquidité bancaire et de la transmission de la politique monétaire. Dans le troisième essai, a été élaboré un modèle de prévision d’inflation dans un des pays membres de la CEMAC à savoir le Tchad. Les modèles BVAR se sont révélés en Afrique Centrale être plus efficaces que les outils traditionnels (AR, ARIMA, VAR).L’analyse de sensibilité entreprise par l’approche bayesienne indique que la surliquidité exercerait des tensions inflationnistes dans la zone. / This thesis is based on three essays focused on analysis of the excess liquidity in the CEMAC countries. The first one identifies the determinants of excess liquidity in developing countries by studying the case of CEMAC member countries from 1985 to 2002. The GMM estimator used has shown that the excess liquidity in Central Africa derived from both the prudence of commercial banks and exogenous factors. The precaution of Commercial Banks can be explained by the financial crisis in 1980s, the restructuring of the banking system, the instability of deposits and a very risky economic environment. The increasing in oil prices fueling excess reserves due to the low absorption capacity of countries in the region. In the second essay, it was discussed the transmission channels in Central Africa. The VAR model used has shown that the interest rate channel is the lowest. This is exactly the lack of a financial market that does not allow ensuring the function of the recycling of liquidity and the transmission of mone ary policy. At the last essay, it was developed a forecasting model of inflation in Chad which is member of CEMAC countries. BVAR models have been shown in Chad to be more effective than traditional tools (AR, ARIMA and VAR). A sensitivity analysis undertaken by the Bayesian approach indicates that the excess liquidity would exert inflationary pressures.
282

Inferência Bayesiana em Modelos de Volatilidade Estocástica usando Métodos de Monte Carlo Hamiltoniano / Bayesian Inference in Stochastic Volatility Models using Hamiltonian Monte Carlo Methods

Dias, David de Souza 10 August 2018 (has links)
Este trabalho apresenta um estudo através da abordagem Bayesiana em modelos de volatilidade estocástica, para modelagem de séries temporais financeiras, com o uso do método de Monte Carlo Hamiltoniano (HMC). Propomos o uso de outras distribuições para os erros da equação de observações do modelos de volatilidade estocástica, além da distribuição Gaussiana, para tratar problemas como caudas pesadas e assimetria nos retornos. Além disso, utilizamos critérios de informações, recentemente desenvolvidos, WAIC e LOO que aproximam a metodologia de validação cruzada, para realizar a seleção de modelos. No decorrer do trabalho, estudamos a qualidade do método HMC através de exemplos, estudo de simulação e aplicação a conjunto de dados. Adicionalmente, avaliamos a performance dos modelos e métodos propostos através do cálculo de estimativas para o Valor em Risco (VaR) para múltiplos horizontes de tempo. / This paper presents a study using Bayesian approach in stochastic volatility models for modeling financial time series, using Hamiltonian Monte Carlo methods (HMC). We propose the use of other distributions for the errors of the equation at stochastic volatiliy model, besides the Gaussian distribution, to treat the problem as heavy tails and asymmetry in the returns. Moreover, we use recently developed information criteria WAIC and LOO that approximate the crossvalidation methodology, to perform the selection of models. Throughout this work, we study the quality of the HMC methods through examples, simulation study and application to dataset. In addition, we evaluated the performance of the proposed models and methods by calculating estimates for Value at Risk (VaR) for multiple time horizons.
283

Parasite genetic factors implicated in cerebral malaria / Facteurs génétiques parasitaires impliqués dans le neuropaludisme

Almelli, Talleh 27 May 2014 (has links)
Le paludisme à P. falciparum est l’une des causes majeures de mortalité et de morbidité dans le monde. Ce parasite est responsable de plusieurs manifestations cliniques allant du portage asymptomatique et infections non compliquées aigüe au paludisme grave et compliqué, tel que le neuropaludisme. Nous avons émis l’hypothèse que l’expression différentielle des gènes contribue à la variation phénotypique de parasites, entraînant des interactions spécifiques avec l’hôte, qui à son tour déterminent le type de manifestations cliniques du paludisme. L’objectif principal de cette étude était d’identifier les facteurs génétiques de P. falciparum impliqués dans la pathogenèse du neuropaludisme. Ceci a été réalisé par l’analyse complète du transcriptome d’isolats provenant d’enfants camerounais porteurs asymptomatiques (PA) ou atteints d’accès simple (AS) ou de neuropaludisme (NP). Le transcriptome du clone non sélectionnée (3D7) et la lignée sélectionnée (3D7-Lib) a été également analysé. Les résultats ont montré la surexpression de plusieurs gènes chez des isolats provenant d’enfants atteints de neuropaludisme et chez la lignée 3D7-Lib, par rapport à ceux provenant d’enfants asymptomatiques et 3D7, respectivement. L’analyse de l’ontologie de gène indique que les gènes potentiellement impliqués dans la pathogenèse, la cytoadhérence et l’agrégation des érythrocytes sont surreprésentés parmi les gènes surexprimés chez les isolats de CM et 3D7-Lib. Les résultats les plus marquants étaient la surexpression des gènes var (groups A et B) portant les domaines cassettes DC4, DC5, DC8 et DC13 et les gènes avoisinants rif chez les isolats de NP et la lignée 3D7-Lib, par rapport aux isolats de PA et au clone non sélectionné 3D7, respectivement. Le rôle joué par ces gènes dans la virulence parasitaire est lié à la cytoadhérence, c’est-à-dire la capacité de leurs protéines exprimées à interagir entre les érythrocytes parasités et les récepteurs endothéliaux post capillaires. Parmi ces récepteurs, le CD36 et inter cellular adhesion molecule 1 (ICAM-1) ont été les plus couramment utilisés par les isolats. L’étude sur l’implication de ces deux récepteurs, ainsi que celle des ligands PfEMP-1, dans la pathogenèse du neuropaludisme devrait être approfondie poursuivie. Nous avons analysé le phénotype de cytoadhérence et les profils de transcription des variantes de Pfemp-1 des isolats frais provenant des enfants béninois atteints de NP ou AS à l’aide du test d’adhérence statique aux récepteurs CD36, ICAM-1 et CSPG et au moyen de RT-PCR quantitative pour les groupes A, B, var2, var3, DC8 et DC13. Nos résultats montrent que le niveau de cytoadhérence des parasites associés au neuropaludisme au CD36 est significativement plus important que celui des parasites associés à l’accès simple. En outre, nous n’avons pas trouvé de différence significative entre la cytoadhérence des isolats de deux groupes cliniques à ICAM-1 et au CSPG. En outre, les niveaux d’expression des groupes var A, B, var2, var3 et du DC8 et DC13 sont plus élevés chez les isolats associés au neuropaludisme que chez les isolats associés à l’accès simple. Nos résultats montrent également que, chez les parasites provenant de NP le haut niveau de cytoadhérence des parasites au CD36 est corrélé au niveau de l’expression de groupe B de gènes var. En revanche, les profils d’expression des groupes spécifiques du gène var et le phénotype de cytoadhérence aux récepteurs ICAM-1 et CSPG n’étaient pas corrélés. Nos résultats suggèrent un rôle important du récepteur CD36 et des protéines codées par les variantes de PfEMP-1 codées par le groupe B dans la pathogenèse du neuropaludisme. / Plasmodium falciparum infection is a major cause of mortality and morbidity worldwide. This parasite is involved in several clinical manifestations, ranging from asymptomatic carriage and acute uncomplicated to severe and complicated malaria, including cerebral malaria. We hypothesized that differential gene expression contributes to phenotypic variation of parasites leading to specific interaction with the host which induces several clinical categories of malaria. The principal aim of this study was to identify parasite genetic factors implicated in the pathogenesis of cerebral malaria. We investigated the whole transcriptome of parasites isolated from Cameroonian children with asymptomatic (AM), uncomplicated (UM) and cerebral malaria (CM). We also investigated the transcriptome of 3D7 clone and the selected 3D7-Lib line. Our results revealed the up-regulation of several genes in CM isolates and 3D7-Lib line compared to AM isolates and 3D7 clone respectively. Gene ontology analysis indicates an over-representation of genes implicated in pathogenesis, cytoadherence, and erythrocyte aggregation among up-regulated genes in CM and 3D7-Lib. The most remarkable outcomes were the up-regulation of UPS A and B var genes containing architectural Domains Cassettes DC4, DC5, DC8, and DC13 and their neighboring rif genes in isolates from CM and 3D7-Lib line, compared with isolates from AM and the unselected 3D7 line, respectively. The involvement of these genes in parasite virulence rises from the ability of their encoded proteins to mediate cytoadherence of infected erythrocytes to post-capillary endothelial receptors. Of these receptors, CD36 and Inter Cellular Adhesion Molecule-1 (ICAM-1) were found as the most commonly used by the isolates. The implication of these two receptors, as well as that of PfEMP-1 ligands in the pathogenesis of CM needs to be more elucidated. We examined the adhesive phenotype and the transcription patterns of Pfemp-1 variants of fresh isolates from Beninese children with CM or UM malaria by static binding assay to CD36, ICAM-1 and CSPG and RT-qPCR for groups A, B, var2, var3, DC8, and DC13. Our findings showed that isolates from CM patients bind more to CD36 than those from UM cases. No differences were observed in binding levels to ICAM-1 or CSPG between these two groups. Furthermore, CM isolates transcribed groups A, B, var2, var3, DC8 and DC13 of var genes at higher levels than UM isolates. Interestingly, the high transcription levels of group B in CM parasites correlated with their higher level of binding to CD36. In contrary, the expression profiles of a specific var group and the binding phenotype of isolates to ICAM-1 and to CSPG were not correlated. Our findings support the implication of CD36 along with PfEMP-1 variants encoded by group B in cerebral malaria pathogenesis.
284

Isolamento biomonitorado de substâncias ativas de Croton pallidulus var. pallidulus (Euphorbiaceae) / Isolantion of bioactive compounds from Croton pallidulus var. pallidulus (Euphorbiaceae)

Soares, Sarah Aparecida 05 December 2013 (has links)
Croton (Euphorbiaceae), é um gênero promissor para pesquisa de compostos bioativos, tanto pela variedade de compostos químicos encontrados, quanto pela diversidade de uso na medicina tradicional/popular. Estudos farmacológicos comprovaram atividades antimicrobianas, antivirais, anti-inflamatórias, antioxidantes e citotóxicas. Neste trabalho, foram obtidos extratos fracionados em Soxhlet (hexano, diclorometano, acetato de etila e metanol) de folhas e caules de C. pallidulus Baill var. pallidulus (Baill.) L.B. Smith & S.F. Smith. Esses extratos foram avaliados quanto às atividades 1) antibacteriana pelo método de microdiluição em caldo, utilizando Staphylococcus aureus - cepas sensível e resistente à vancomicina, Pseudomonas aeruginosa, Escherichia coli e Salmonella choleraesuis; 2) antioxidante (sequestro do radical livre DPPH); e quanto à toxicidade frente à Artemia salina. A fração mais ativa neste último ensaio foi selecionada para a avaliação da atividade citotóxica utilizando as células de sarcoma uterino humano. Os fenóis totais, e flavonóis e flavonas totais foram quantificados por métodos colorimétricos. O fracionamento dos extratos hexânico e diclorometânico foi feito por cromatografia em coluna de sílica, enquanto o dos extratos de acetato de etila e metanol, em coluna de PVPP. O isolamento das substâncias das frações ativas nos ensaios de atividade antibacteriana (S. aureus - sensível) e de toxicidade frente à A. salina foi realizado por CLAE semipreparativo. O teor de fenóis totais de C. pallidulus var. pallidulus foi de 1,95 g EAG/100g MS e de flavonóis e flavonas totais foi de 0,56 g EQ/100g MS. Todos os extratos apresentaram atividade contra S. aureus (sensível e resistente), com CBM de 2048 mg/L, exceto o extrato metanólico que apresentou atividade apenas contra S. aureus (sensível). Nenhum extrato apresentou atividade contra as demais cepas. As frações FH-5A - hexano (CBM de 256mg/L) e FA-7 - acetato de etila (CBM de 1024mg/L) foram as que apresentaram maior atividade antibacteriana. A fração FH-5A foi separada em coluna de sílica, e suas subfrações apresentaram atividades antibacterianas menores que a fração que lhe deu origem. Das sete substâncias majoritárias isoladas da fração FA-7, nenhuma apresentou atividade antibacteriana. Seis delas são flavonoides: três C-glicosídeos de apigenina, um O-glucosídeo de campferol, um O-galactosídeo de isoramnetina e um O-rutinosídeo de isoraminetina. Apenas o extrato diclorometânico apresentou atividade no ensaio de toxicidade frente à A. salina, com CL50 de 385mg/L. A fração com maior toxicidade foi a FD-4A, com CL50 de 101mg/L. As substâncias mais abundantes nesta fração foram isoladas e identificadas como 8,9-secocauranos, derivados da kongensina F. Quanto a atividade citotóxica, a atividade de FD-4A foi três vezes maior que a atividade do extrato diclorometânico. Os extratos de acetato de etila e de metanol apresentaram os maiores valores de atividade antioxidante: 12,11 e 11,77 gEQ/100g, respectivamente. Verificou-se que os flavonoides foram as substâncias fenólicas que mais influenciaram na atividade antioxidante das frações dos extratos de acetato de etila e de metanol. Com esses resultados verifica-se que C. pallidulus var. pallidulus possui ação antibacteriana, citotóxica e antioxidante, sendo uma potencial fonte para novos fármacos para tratamento de doenças infecciosas e câncer. Conseguiu-se também isolar três 8,9-secocauranos, derivados da kongensina F, que aparentemente não haviam ainda sido descritos / Croton (Euphorbiaceae), is a promising genre for investigation of bioactive compounds, both for the variety of compouds, as for the diversity of use in traditional medicine. Pharmacological studies have demonstrated antimicrobial, antiviral, anti-inflammatory, cytotoxic, and antioxidant activities. In this study, fractionated extracts of leaves and stems of C. pallidulus Baill var. pallidulus (Baill.) L.B. S.F. Smith & Smith were obtained throught Soxhlet (hexane, dichloromethane, ethyl acetate and methanol). The following activities of these extracts were tested: 1) antibacterial activity, through microbroth dilution assay using: Staphylococcus aureus - sensitive and vancomycin-resistant strains, Pseudomonas aeruginosa, Escherichia coli and Salmonella choleraesuis; 2) antioxidant activity (free radical DPPH scavenging) and Artemia salina toxicity evaluation. The most active fraction in the latter test was selected to evaluate the cytotoxic activity using human uterine sarcoma cells. The total phenols, and total flavonols and flavones were quantified by colorimetric methods. The fractionation of hexane and dichloromethane extracts was done through silica column chromatography, while PVPP column was used for the ethyl acetate and methanol extracts. The isolation of the active fractions major compounds in the antibacterial activity (S. aureus - sensitive) and A. saline toxicity assays were performed by semipreparative HPLC. The total phenolic content of C. pallidulus var. pallidulus was 1.95 g GAE/100g DM and total flavonols and flavones was 0.56 g QE/100g MS. All extracts showed activity against S. aureus (sensitive and resistant), with MBC of 2048 mg/L, except for the methanol extract, which showed activity only against S. aureus (sensitive). Extracts showed no activity against the other strains. Fractions FH-5A-hexane (MBC: 256mg/L) and FA-7-ethyl acetate (MBC: 1024mg/L) showed the highest antibacterial activity. The fraction FH-5A was separated on a silica column, and its subfractions showed smaller antibacterial activity than FH-5A. The seven major compounds isolated from the FA-7 fraction, showed no antibacterial activity. Six of them are flavonoids, three apigenin C-glycosides, one kaempferol O-glucoside, one isorhamnetin O-galactoside and one isorhamnetin O-rutinoside. Only the dichloromethane extract showed activity in the A. salina toxicity assay, LC50: 385mg/L. The fraction with the highest toxicity was the FD-4A, LC50: 101mg/L. The most abundant substances in this fraction were isolated and identified as 8,9 - secokauranes derived from kongensin F. As for the cytotoxic activity, the FD-4A activity was three times higher than the dichloromethane extract activity. The extracts of ethyl acetate and methanol showed the highest antioxidant activity: 12.11 and 11.77 gQE/100g, respectively. It was observed that flavonoids were the phenolic substances that most influenced the antioxidant activity of the fractions of the ethyl acetate and methanol extracts. With these results we suggest that C. pallidulus var. pallidulus has antibacterial activity, cytotoxic and antioxidant properties, being a potential source of new drugs for treatment of infectious diseases and cancer. We also isolated three 8,9-secokauranes derived from kongensin F, which apparently had not been described yet
285

Avaliação do glicerol proveniente da fabricação do biodiesel como substrato para produção de endotoxinas por Bacillus thuringiensis var. israelensis / Evaluation of glycerol derived from biodiesel production as substrate for endotoxins production by Bacillus thuringiensis var. israelensis.

Barbosa, Claudia Rodrigues 19 June 2009 (has links)
A utilização do glicerol proveniente da fabricação do biodiesel como substrato para a obtenção de produtos biotecnológicos é uma alternativa promissora como forma de disposição adequada deste subproduto. O bioinseticida formulado com toxinas de Bacillus thuringiensis tem sido utilizado para o controle de insetos veiculadores de doenças, como a dengue, que atingem milhões de pessoas em todo o mundo. Para que este bioinseticida seja competitivo com os inseticidas químicos é necessário que o custo de sua produção seja diminuído, o que pode ser feito com a utilização de fontes de carbono alternativas, de forma a diminuir o custo do meio de fermentação. Neste trabalho, empregou-se o glicerol proveniente da fabricação do biodiesel de sebo bovino como componente do meio de fermentação para a produção de bioinseticida por Bacillus thuringiensis var. israelensis. Foram avaliados diferentes tratamentos do resíduo contendo glicerol, baseados em acidificação, decantação e aquecimento, para remoção de impurezas. O ajuste do pH até 7 pela adição de ácido fosfórico, seguido de decantação, aquecimento para remoção de metanol e nova decantação, foi a forma de tratamento escolhida, uma vez que proporcionou a maior atividade tóxica do meio fermentado contra larvas de Aedes aegypti. O meio de fermentação foi formulado determinando-se as concentrações de glicerol, extrato de levedura, sulfato de amônio e cloreto de cálcio que proporcionaram a maior atividade larvicida do meio fermentado, de acordo com planejamento fatorial 24. A toxicidade foi avaliada pela CL50 (concentração do complexo esporo-cristal necessária para matar 50% da população de larvas). O melhor valor de CL50 foi obtido com a utilização de glicerol a 10 g/L, extrato de levedura a 12 g/L, cloreto de cálcio a 0,24 g/L e sem adição de sulfato de amônio. A análise estatística dos dados confirmou a significância das variáveis glicerol, extrato de levedura e cloreto de cálcio sobre a atividade larvicida do meio fermentado. Cloreto de cálcio não influenciou significantemente a produção de esporos pela bactéria, e a taxa de esporulação não foi influenciada por cloreto de cálcio e sulfato de amônio nas concentrações estudadas. Para a otimização da produção de endotoxinas pela bactéria, foi realizado um planejamento fatorial 22, variando-se apenas as concentrações de extrato de levedura e de cloreto de cálcio, fixando-se a concentração de glicerol em 10 g/L e excluindo-se o sulfato de amônio do meio de fermentação. O melhor valor de CL50 (0,295 mg/mL) foi obtido no ensaio com 15 g/L de extrato de levedura e 0,4 g/L de cloreto de cálcio. / The use of glycerol derived from biodiesel production as a substrate for the acquisition of biotechnology products is a promising alternative as an adequate disposal mean of this by-product. The bioinsecticide formulated with toxins from Bacillus thuringiensis has been used to control vectors insects of diseases, such as dengue, which affect millions of people around the world. For this bioinsecticide be competitive with chemical insecticides is necessary a lower cost of its production, which can be achieved by the use of alternative carbon sources in order to reduce the fermentation medium cost. In this work, it was used glycerol from beef tallow biodiesel production as a component of the fermentation medium for the production of bioinsecticide by Bacillus thuringiensis var. israelensis. Different treatments of the residue containing glycerol, based on acidification, sedimentation and heating, to remove impurities, were evaluated. The adjustment of pH to 7 by addition of phosphoric acid, followed by decantation, then heating for removal of methanol, and a new decantation, was the treatment selected, since it provided the highest toxic activity of the fermented broth against Aedes aegypti larvae. The fermentation medium was formulated by determining the concentration of glycerol, yeast extract, ammonium sulfate and calcium chloride that provided the greatest larvicidal activity of the fermented broth according to 24 factorial design. The toxicity was measured by the LC50 (concentration of the spore-crystal complex required to kill 50% of the larvae). The best value of LC50 was obtained using glycerol at 10 g/L, yeast extract at 12 g/L, calcium chloride at 0.24 g/L and without addition of ammonium sulfate. Statistical analysis confirmed the significance of the variables glycerol, yeast extract and calcium chloride on the larvicidal activity of fermented broth. Calcium chloride did not influence significantly the production of spores by the bacteria and the sporulation ratio was not affected by calcium chloride and ammonium sulfate at the studied concentrations. For the endotoxins production optimization, a 22 factorial design was carried out, varying only the concentrations of yeast extract and calcium chloride, maintaining the concentration of glycerol at 10 g/L and excluding ammonium sulfate of the fermentation medium. The best value of LC50 (0,295 mg/mL) was obtained in the assay with 15 g/L of yeast extract and 0.4 g/L of calcium chloride.
286

O BNDES é contracíclico? Uma análise da instituição no período de 1999 a 2012 / Is The BNDES counter-cyclical? An analysis of the institution from 1999 to 2012

Cardoso, Wilson Lira 06 June 2014 (has links)
A crise mundial de 2008 ressaltou um caráter importante desempenhado pelos Bancos Públicos de Desenvolvimento: a sua política anti-cíclica. Como previsto para instituições financeiras públicas na teoria keynesiana, esses orgãos passam a aumentar o número de empréstimos concedidos e injetar mais dinheiro em momentos de queda geral da atividade econômica. No caso do Brasil, uma parte dos autores defende que a atuação contra-cíclica do BNDES foi benéfica para a manutenção da liquidez na economia durante os períodos de turbulência econômica. Já outros autores defendem que a intervenção Estatal pelo BNDES provoca um efeito crowding-out sobre o crédito, inibindo a formação de um mercado de crédito privado de longo prazo. O Objetivo do trabalho é fazer uma análise objetiva da trajetória do BNDES de 1999 a 2012, procurando discernir se a sua atuação ao longo desse período pode ser efetivamente caracterizada, como defende o governo e a própria instituição, como contra-cíclica. Para efetuar esse trabalho usaremos métodos econométricos de séries temporais a partir de dados de série de variáveis macroeconômicas agregadas para uma análise quantitativa do comportamento do BNDES ao longo desse período. Juntamente com isso, será feita também uma analise qualitativa das séries históricas com o objetivo de qualificar e interpretar economicamente tanto os dados, quanto os resultados obtidos. / The Global Financial Crisis of 2008 underscored an important characteristic played by Public Development Banks: its anti-cyclical policy. As regarded for Public Financial Institutions in Keynesian theory, those institutions increase their volume of loans and inject more money in periods of general economic downturn. In Brazil, some authors argue that the counter- cyclical role of BNDES was beneficial to maintain liquidity in the economy during periods of economic turmoil. On another hand, others authors stand that State intervention by BNDES causes a crowding-out effect on credit, inhibiting the formation of a private market for long-term credit. The goal of this dissertation is to write an objective analysis of the trajectory of BNDES from 1999 to 2012, seeking to discern whether its activity during this period can be effectively characterized, like the government and the institution itself arms, as countercyclical. In order to do that, we are going to use time series econometric methods based on data series of aggregate macroeconomic variables for a quantitative analysis of the BNDES\'s behavior over that period. Along with this, we also made a qualitative analysis of the time series in order to qualify and interpret both economic data and the obtained results.
287

Aproveitamento da água residual do processamento do pescado em irrigação / Reuse of fish processing wastewater in irrigation

Lama, Felipe Morais Del 08 November 2018 (has links)
A água residual do processamento do pescado contém elevados teores de matéria orgânica, íons e microrganismos. Devido a essa composição, há a necessidade de tratamento antes do retorno do efluente aos corpos hídricos ou ao meio ambiente. Mesmo após o tratamento, ainda pode haver contaminantes presentes no efluente tratado. Desse modo, práticas sustentáveis de gerenciamento de resíduos, tais como o reúso destes na agricultura, mostram-se adicionais ao tratamento e alternativas ao lançamento do material residual nos diferentes ecossistemas. O objetivo deste trabalho consistiu, inicialmente, em caracterizar química, física e microbiologicamente a água residual proveniente de uma indústria que realiza o beneficiamento de tilápia (Oreochromis niloticus), bem como do efluente tratado, oriundo de uma estação pertencente à própria indústria. Observou-se uma eficiência média de remoção de 90% da matéria orgânica. A concentração microbiana, todavia, apresentou aumento considerável no efluente tratado, tendo sido observado maior número de colônias de Escherichia coli. Ademais, esse mesmo material líquido apresentou concentração média de 123,4 mg/L de nitrogênio e 10,55 mg/L de fósforo, valores considerados elevados. Isso pode ser explicado pela adição inadequada de outros resíduos presentes na indústria, como dejetos humanos, às etapas de tratamento. Realizaram-se, posteriormente, ensaios de irrigação em plantas e sementes de alface (Lactuca sativa var.crispa), empregando-se cada resíduo líquido nas concentrações de 25%, 50%, 75% e 100%. Não houve efeitos adversos ao potencial fisiológico das sementes. Para as plantas cultivadas em substrato de argila, o aumento da concentração dos efluentes aplicados acarretou o acúmulo do íon cloreto (Cl-) nas alfaces. Nesse contexto, constataram-se correlações negativas entre o aumento da concentração de cloreto nos tecidos vegetais, a bioamassa e o crescimento da parte aérea e do sistema radicular. Observou-se, ainda, o aumento da taxa de mortalidade vegetal nos tratamentos irrigados com água residual, à medida que se aumentaram as concentrações desse resíduo. Os resultados referentes à irrigação permitem concluir que o efluente tratado, nas concentrações de 25% e 50%, possibilitou melhor desempenho agronômico. As análises microbiológicas das plantas irrigadas com o efluente em tais concentrações, por sua vez, não mostraram a presença de bactérias patogênicas constantes na legislação brasileira. Apesar disso, melhor gerenciamento das etapas do tratamento dos efluentes faz-se necessário, a fim de que a prática de reúso agrícola seja segura e permita geração de receitas, quesitos estes indispensáveis para a maior ecoeficiência das empresas / Fish processing wastewater contains high levels of organic matter, ions and microorganisms. Because of this composition, it is necessary to treat this effluent before its return to water bodies or the environment. Despite the treatment, there can be some remaining contaminants in the treated wastewater. Thus, sustainable practices regarding the wastes management, such as their reuse in agriculture, turn out to be an additional option to the treatment and an alternative to the disposal of these compounds in different ecosystems. The objective of this work was initially to perform chemical, physical and microbiological characterizations of a raw wastewater coming from a tilapia (Oreochromis niloticus) processing plant as well as the treated wastewater. The latter was collected from a waste treatment facility located beside and belonging to this same industry. There was a removal efficiency of 90% in organic matter. Nevertheless, bacteria concentration, mainly Escherichia coli, increased in the treated wastewater. Furthermore, this same liquid waste presented a medium concentration of 123.4 mg/L in nitrogen, and 10.55 mg/L in phosphorus, values considered important. These facts can be explained by the inappropriate addition, during the treatment stages, of other wastes present in the industry like human excrements. Secondly, irrigation trials were performed in lettuce (Lactuca sativa var.crispa) and its seeds by using each wastewater at concentrations of 25%, 50%, 75% and 100%. There were not any adverse effects to the seeds physiological potential. For plants which were grown in a clay substrate, the increase in the applied effluents caused lettuce to cumulate chloride (Cl-). In this respect, negative correlations between the chloride concentration in plants tissues, biomass, and shoot and root growth, were observed. There was still an increase in the plants mortality rate in lettuce irrigated with raw wastewater as the concentrations of this effluent became greater. These tests showed that the treated wastewater at concentrations of 25% and 50% had the best agronomic performance. The microbiological analyses of these treatments in turn did not reveal the presence of pathogenic bacteria present in the Brazilian laws. Despite this fact, a better management of the treatment stages is compulsory in order to achieve a safer wastewater reuse. Moreover, there can be a production of incomes, which represents an asset for ecoefficient companies
288

Essays in empirical macroeconomics with application to monetary policy in a data-rich environment

Ahmadi, Pooyan Amir 05 July 2010 (has links)
Diese Dissertation besteht aus vier eigenständigen Aufsätzen. Das erste Kapitel liefert eine Einleitung uns einen Literaturüberblick. Im zweiten Kapitel schätzen wir die Effekte eines geldpolitischen Schocks in einer Bayesianischen faktorerweiterten Vektorautoregression. Als ein Identifikationsschema schlagen wir theoretisch fundierte Vorzeichenrestriktionen vor, welche auf die angemessenen Impuls-Antwortfolgen auferlegt werden können. Der Vorteil der faktorbasierten Vorzeichenrestriktion liegt in der Möglichkeit sehr viele theoretische fundierte Restriktionen zu setzen um so exakter zu identifizieren. Im dritten Kapitel untersuchen wir die Rolle der Geldpolitik während der Weltwirtschaftskrise in den USA. Die besondere Rolle der Geldpolitik gilt seit Friedman and Schwartz [1963] als gängige Meinung. In diesem Papier versuchen wir die entscheidenden Dynamiken der Zwischenkriegszeit mit dem BFAVAR Modell abzubilden und die Effekte geldpolitischer Schocks zu analysieren. Weiterhin schauen wir uns die Effekte der systematischen Komponente der Geldpolitik an. Wir finden heraus, dass der Anteil der Geldpolitik insgesamt zwar präsent allerdings recht gemäßigt vorhanden. Im vierten Kapitel werden die makroökonomischen Dynamiken innerhalb des Euroraumes untersucht. Hierbei schlage ich einen neuen Ansatz vor um die vielen relevanten Interrelationen effizient und sparsam zu vereinbaren. Ein faktorbasiertes DSGE Modell wird gemeinsam mit einem dynamischen Faktormodell geschätzt. Hierbei wird explizit ökonomische Theorie zur Datenanalyse verwendet. Zur Identifikation makroökonomischer Schocks verwende ich sowohl Vorzeichenrestriktionen wie auch die DSGE Rotation. / This thesis consists of four self-contained chapters. The first chapter provides an introduction with a literature overview. In Chapter 2 we estimate the effects of monetary policy shocks in a Bayesian Factor- Augmented vector autoregression (BFAVAR). We propose to employ as an identification strategy sign restrictions on the impulse response function of pertinent variables according to conventional wisdom. The key strength of our factor based approach is that sign restrictions can be imposed on many variables in order to pin down the impact of monetary policy shocks. Thus an exact identification of shocks can be approximated and monitored. In chapter 3 the role of monetary policy during the interwar Great Depression is analyzed. The prominent role of monetary policy in the U.S. interwar depression has been conventional wisdom since Friedman and Schwartz [1963]. This paper attempts to capture the pertinent dynamics through a BFAVAR methodology of the previous chapter. We find the effects of monetary policy shocks and the systematic component to have been moderate. Our results caution against a predominantly monetary interpretation of the Great Depression. This final chapter 4 analyzes macroeconomic dynamics within the Euro area. To tackle the questions at hand I propose a novel approach to jointly estimate a factor-based DSGE model and a structural dynamic factor model that simultaneously captures the rich interrelations in a parsimonious way and explicitly involves economic theory in the estimation procedure. To identify shocks I employ both sign restrictions derived from the estimated DSGE model and the implied restrictions from the DSGE model rotation. I find a high degree of comovement across the member countries, homogeneity in the monetary transmission mechanism and heterogeneity in transmission of technology shocks. The suggested approach results in a factor generalization of the DSGE-VAR methodology of Del Negro and Schorfheide [2004].
289

Analyse des facteurs d’hôte et facteurs parasitaires dans le paludisme grave d’importation / Analysis of host factors and parasitic factors in severe imported malaria

Argy, Nicolas 06 July 2015 (has links)
Le paludisme est une infection parasitaire de répartition mondiale notamment en zones intertropicales où l’infection par Plasmodium falciparum est responsable de centaines de milliers de morts par an principalement chez les enfants de moins de cinq ans. Le paludisme constitue également un problème en France par l’importation de cas de paludisme chez le voyageur de retour de zone d’endémie. L’infection à Plasmodium falciparum dans cette population, considérée comme à risque de développer les formes graves de la maladie, peut se présenter sous différentes formes cliniques plus ou moins associées au risque de mortalité. Même si certains facteurs de risque de gravité tels que l’âge et l’immunité ont été identifiés, cette interaction complexe hôte-parasite n’a été largement étudiée que chez l’enfant en zone d’endémie et peu de données sont disponibles pour le paludisme d’importation. L’objectif de ces travaux de thèse repose sur l’analyse des facteurs d’hôte et des facteurs parasitaires intervenant dans le paludisme d’importation. A travers le réseau de surveillance du centre national de référence du paludisme en France métropolitaine, l’ensemble des données démographiques, épidémiologiques, cliniques et biologiques des cas de paludisme d’importation, notifiés entre 2011 et 2015, ont été collectées ainsi que les échantillons ayant servis au diagnostic. Après expertise diagnostique, le plasma obtenu après centrifugation a été utilisé pour les dosages des antipaludéens, pour la quantification d’HRP2 ainsi que pour la sérologie anti-palustre. L’ARN extrait par le TRIZOL® à partir du culot globulaire a été utilisé pour l’étude de l’expression des gènes var et des domaines cassettes par qRT-PCR. Le culot de globules rouges parasités a été mis en culture pour la maturation des formes parasitaires en vue de l’étude du phénotype de cytoadhérence sur les récepteurs solubles CD36, ICAM-1, EPCR et du phénomène de rosetting . L’ensemble de ces études a été réalisé sur une population de patients dans le cadre du paludisme d’importation groupée en migrants de première génération, migrants de deuxième génération et voyageurs/expatriés et dont la présentation clinique du paludisme d’importation a été classée en paludisme « très grave », paludisme « grave » et paludisme « simple ». L’ensemble des données épidémiologiques, cliniques et biologiques recueillies au cours de l’étude a permis d’identifier l’âge élevé, l’origine ethnique, la profondeur de la thrombopénie et l’absence d’antécédents de paludisme comme des facteurs de risque associés à la survenue d’un accès palustre « très grave », entité clinique caractérisée pour une biomasse parasitaire séquestrée élevée. L’effet de la pré-exposition au parasite, reflété par le statut sérologique des patients, semble être à l’origine de la présentation clinique de la maladie en limitant notamment la biomasse parasitaire séquestrée au cours de l’accès palustre. L’étude de l’expression des gènes var et des domaines cassettes réalisée dans cette population, en fonction de la présentation clinique, de l’origine ethnique et du statut sérologique des patients, a révélé une surexpression du groupe de gènes var A et B et des motifs protéiques composant les domaines cassettes DC4, DC8 et DC13 dans le paludisme « grave » et « très grave » d’importation au sein de cette population hétérogène de patients. L’étude du phénotype de cytoadhérence et du rosetting, réalisée dans un autre groupe de patients rencontré dans le cadre du paludisme d’importation, a identifié le rosetting comme le phénotype d’adhérence à l’origine de l’accès palustre « très grave ». Le profil d’expression des gènes var et domaines cassettes correspondants à cette population a confirmé les observations antérieures et corrèle le phénotype de rosetting à l’expression des motifs protéiques DBLß3 et DBLa2 de DC4 et DC8 (...) / Malaria is a worldwide parasitic infection especially in tropical area where Plasmodium falciparum infection is responsible for hundreds of thousands annually mainly among children under five years old. Malaria is also a problem in France by the importation of malaria cases in travelers coming from endemic area. The Plasmodium falciparum infection in this population, considered at risk of developping severe malaria, can present different clinical forms more or less associated with mortality.While some risk factors for severity like age and immunity have been identified, this complex host-parasite interactions have been widely studied in children in endemic areas and few data are available for imported malaria. The aim of the thesis work is based on analysis of host factors and parasite factors in imported malaria.Through the monitoring network of the French National reference center of malaria, all the demographic, epidemiological, clinical and laboratory of imported malaria cases, notified between 2011 and 2015, were collected and also samples of the parasitological diagnosis. After diagnostic expertise, the plasma obtained after centrifugation was used for determinations of antimalarial drugs, for quantification of plasmatic HRP2 and for serological tests. RNA extracted by the Trizol® from red cells pellets was used to study the expression of var genes and domain cassettes by qRT-PCR. The pellet of parasitized red blood cells were cultured for maturation of parasitic forms for the study of phenotype cytoadherence on soluble receptor CD36, ICAM-1 and EPCR and for the study of the rosetting phenomenon. All of these studies was conducted in an imported malaria context,in a population of patients composed by first-generation migrants, second-generation migrants and travelers / expatriates and whose clinical presentation of imported malaria was classified into very severe (VSM), mild severe (MSM) and uncomplicated malaria (UM).All the epidemiological, clinical and biological data collected during the study identified the high age, ethnicity, depth of thrombocytopenia and no history of malaria as factors risk associated with the occurrence of very severe malaria, clinical entity characterized by high sequestered parasite biomass. The effect of pre-exposure to the parasite, reflected by the serological status of patients, seems to be the cause of the clinical presentation of the disease in particular by limiting parasite biomass sequestered during malaria. The study of the expression of var genes and domain cassettes performed in this population, according to clinical presentation, ethnicity and the serological status of patients, revealed an overexpression of the group of var genes A and B and protein patterns of the domain cassette DC4, DC8 and DC13 in mild severe and very severe malaria within this heterogeneous patient population. The study of cytoadherence phenotype and rosetting, made in another group of patients in imported malaria context, identified the rosetting as adhesion phenotype causing very severe malaria. The expression profile of var genes and domain cassettes corresponding to this population confirmed earlier observations and correlates rosetting phenotype to the expression of DBLß3 and DBLa2 of DC4 and DC8 (...)
290

Otimização das condições de cultivo de 'Rhizopus microsporus' var. 'rhizopodiformis' para a produção, isolamento e identificação de metabólitos com atividade antimicrobiana / Otimization of the conditions of cultivation of Rhizopus microsporus var. rhizopodiformis for the production, isolation and identification of metabólites with antimicrobial activity

Camillo, Ana Silvia Ciscato 12 April 2007 (has links)
O fungo Rhizopus microsporus var. rhizopodiformis foi submetido a determinadas condições de cultivo, objetivando produzir substâncias com atividade antimicrobiana. O microorganismo foi transferido da sílica, na qual foi armazenado, e incubado por sete dias em meio aveia-ágar para o crescimento prévio. Em seguida, 4 x 106 esporos/mL de meio foram transferidos para o meio pré-fermentativo e incubado por 24 horas, seguido de transferência para meio fermentativo (meio Czapek, meio Jackson e meio Vogel) e incubado por períodos de tempo determinados. Além disso, foi incubado em meio fermentativo de arroz por 20 dias. Após a fermentação nos diferentes meios, o caldo da cultura foi obtido por filtração e submetido a partições utilizando-se solventes orgânicos: acetato de etila e n-butanol, os quais foram recuperados por evaporação a vácuo. Os extratos obtidos dessas partições foram submetidos aos testes de bioautografia para determinação das frações ostentando atividade antimicrobiana. Os extratos em acetato de etila dos quatro meios fermentativos apresentam tal atividade. As frações ativas foram submetidas a diferentes modalidades cromatográficas para isolamento das substâncias, como a cromatografia liquida em coluna de sílica e a Cromatografia Liquida de Alta Eficiência. Foram isolados quatro metabólitos secundários a partir das frações obtidas em acetato de etila dos meio liquido Jackson e do meio sólido de arroz. Foram identificadas duas dicetopiperazinas (ciclos Leu-Pro e Leu-4-OH-Pro) e um derivado aromático contendo nitrogênio na porção alifática da molécula. Foram determinadas as concentrações inibitórias mínimas (CIM) das substâncias isoladas contra os seguintes microorganismos: Kocuria rhizophila (ATCC 9341), Staphylococcus aureus (ATCC 25923) Candida albicans (ATCC 10231), Escherichia coli (ATCC 25922) e Pseudomonas aeruginosa (ATCC 27853). Todos os extratos obtidos dos meios de cultura apresentaram atividade contra S. aureus e K. rhizophila, bem como o extrato metanólico dos micélios. Apenas os extratos em n-butanol não foram ativos. Nos ensaios de microdiluição, as três ix substâncias identificadas apresentaram CIMs entre 400 e 350 μg/mL. Os resultados obtidos indicam que o fungo em questão é uma fonte interessante para obtenção de metabólitos secundários. / The fungus Rhizopus microsporus var. rhizopodiformis was cultivated in different fermentative media aiming to produce secondary metabolites bearing antimicrobial activity. The conidia storage in silica gel was incubated in oat medium for conidia production. After seven days the conidia (4 x 106 conidia/mL) was transferred to a pre-fermentative medium and incubated for 24 h for mycelium production. After that, it was transferred to three fermentative media: Czapek, Jackson and Vogel, and incubated for different periods of time. After fermentation, cultures were filtered and the broth was submitted to partition using ethyl acetate and n-buthanol in sequence, which were, afterwards, recovered under vacuum. The obtained crude extracts were evaluated under bioautography assay aiming to select the most adequate medium for secondary antimicrobial metabolite production. The ethyl acetate extracts obtained from both Jackson and rice media displayed the higher activities. Therefore, they were submitted to different chromatographic means, including silica gel column and HPLC, furnishing four isolated compounds, from which three were identified: two diketopiperazines (cyclos Leu-Pro and Leu-4-OH-Pro) and one aromatic compound containing a nitrogen in the aliphatic moiety. The pure isolated compounds were submitted to microdilution tests against the following bacteria: Kocuria rhizophila (ATCC 9341), Staphylococcus aureus (ATCC 25923) Candida albicans (ATCC 10231), Escherichia coli (ATCC 25922) e a Pseudomonas aeruginosa (ATCC 27853), aiming to determine their Minimum Inhibitory Concentrations (MIC). All the ethyl acetate extracts displayed antimicrobial activity in the bioautography assays against S. aureus and K. rhizophila, as well as the mycelia methanol extracts. Only the n-butanol extracts did not display activity. Regarding the microdilution assay, three of evaluated pure compounds displayed MIC values between 400 and 350 μg/mL. The obtained results indicated that the studied fungus is an interesting source for biologically active secondary metabolites production.

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