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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.
621

Análise da função ventricular direita em dois protocolos de treinamento com bandagem ajustável do tronco pulmonar / Assessment of right ventricular function in two training protocols with adjustable pulmonary banding

Favaro, Gustavo Antonio Guimarães 13 December 2011 (has links)
A transposição das grandes artérias (TGA) com septo interventricular (SIV) íntegro tem como correção ideal a cirurgia de Jatene no período neonatal. Caso o paciente não seja operado nesse período, o ventrículo esquerdo pode-se tornar despreparado para sustentar a circulação sistêmica. O treinamento do ventrículo subpulmonar, através da bandagem do tronco pulmonar (TP), é uma opção terapêutica nestes casos, preparando para posterior correção definitiva. A hipótese da realização de uma bandagem pulmonar com estresse sistólico ajustável para treinar o ventrículo subpulmonar minimizaria as inadequações da bandagem convencional e aperfeiçoaria o preparo destes ventrículos. Estudos prévios desta linha de pesquisa não evidenciaram diferenças funcionais, na condição de repouso, entre os dois protocolos de preparo ventricular com sobrecarga contínua e intermitente. O objetivo do presente estudo foi o de analisar a função ventricular durante o processo de hipertrofia ventricular aguda e as repercussões na função sistólica e diastólica do ventrículo direito (VD), em condições de repouso e estresse farmacológico, em animais jovens, submetidos a dois protocolos de sobrecarga pressórica ajustável, sendo um de forma contínua e outro de forma intermitente. Foram utilizados 19 cabritos hígidos, com idade aproximada de 60 dias e pesos comparáveis, divididos em três grupos: Sham (n = 7, cirurgia controle), Contínuo (n = 6, sobrecarga sistólica contínua do VD), Intermitente (n = 6, 12 horas/dia de sobrecarga sistólica do VD). A sobrecarga sistólica do VD foi mantida por 96 horas no grupo contínuo e por quatro períodos de 12 horas, alternados com 12 horas de descanso, no grupo intermitente. Os animais do grupo Sham foram submetidos ao implante do dispositivo de bandagem, o qual foi mantido desinsuflado. Avaliações ecocardiográficas e hemodinâmicas foram feitas diariamente. A função cardíaca em repouso e sob o estresse farmacológico induzido por dobutamina foi analisada em dois momentos: basal e após 96 horas do início do protocolo de sobrecarga. Após 96 horas de estudo, os animais foram mortos para avaliação dos parâmetros morfológicos. Ao final do protocolo, foi observada uma diferença significativa da espessura do VD no grupo Intermitente (+64,8% ± 23,37%), quando comparado ao grupo Contínuo (+43,9% ± 19,26%; p = 0,001) e de ambos os grupos de estudo quando comparados ao grupo Sham (p < 0,001). Os grupos de estudo apresentaram dilatação do VD no início do protocolo (tempo zero, p < 0,001), quando comparados ao grupo Sham. Entretanto, apenas o grupo Contínuo manteve a dilatação significativa do VD ao longo do protocolo (p < 0,006). Foi observada piora da fração de ejeção nos dois grupos de estudo, logo após o início da sobrecarga sistólica do VD (momento zero e 24 horas; p < 0,002), recuperando-se posteriormente no final do protocolo. No entanto, o grupo Contínuo manteve a fração de ejeção rebaixada por mais tempo que o grupo Intermitente (72 horas versus 48 horas respectivamente, p < 0,001), apesar de estar dentro dos limites da normalidade. Na situação de repouso, o desempenho miocárdico do VD no grupo Contínuo foi significativamente pior que o do grupo Sham, após 72 horas e 96 horas de treinamento ventricular (p < 0,039). Sob estresse farmacológico, o grupo Contínuo apresentou piora dos índices não apenas em relação ao grupo Sham, como também em relação ao grupo Intermitente (p < 0,01). À análise morfológica, ambos os grupos de estudo apresentaram magnitude semelhante de aumentos das massas do VD, apesar do menor tempo de sobrecarga pressórica no grupo intermitente. Apesar de ambos os protocolos de sobrecarga sistólica do VD promoverem ganho de massa ventricular de magnitude semelhante, a sobrecarga sistólica intermitente foi superior no sentido de preservar o desempenho miocárdico do VD em cabritos / The ideal surgical treatment of transposition of the great arteries is the Jatene operation during the neonatal period. If the neonate remains untreated for several reasons, the left ventricle may become unprepared to sustain systemic circulation. The preparation of the subpulmonary ventricle by pulmonary trunk (PT) banding is an option for the 2-stage Jatene operation. The hypothesis of PT banding with an adjustable device to retrain the subpulmonary ventricle could minimize the inadequacies of conventional banding and improve the preparation of those ventricles. Previous studies have shown no differences on systolic function between two different protocols of subpulmonary ventricle retraining, during resting condition. The aim of the present study was to assess ventricular function during two protocols of PT banding and the impact on systolic and diastolic function of the right ventricle (RV), at rest and under pharmacological stress. Nineteen healthy young goats, aged approximately 60 days and with comparable weights, were divided into three groups: Sham (n = 7, surgery control with no systolic overload), Continuous (n = 6, 96 hours of continuous RV systolic overload), Intermittent (n = 6, four 12-hour periods of systolic overload paired with a 12-hour resting period). before and after systolic overload every day postoperatively. Cardiac function at rest and under pharmacological stress induced by dobutamine was assessed on two occasions: baseline and after 96 hours. After 96-hour study period, all the animals were euthanized for morphologic assessment. There was a significant increase in RV free wall thickness of the Intermittent Group (+64.8% ± 23.37%) at the end of the protocol, when compared to Continuous Group (+43.9% ± 19.26%, p = 0.015). Both study groups presented a dilated RV after starting systolic overload (time zero, p < 0.001), as compared to Sham group. However, only Continuous group remained with significant RV dilation throughout the protocol (p < 0.006). Worsening of RV ejection fraction was observed in the two study groups after beginning systolic overload as well (time zero and 24 hours, p < 0.002), with recovery to normal levels at the end of the protocol. Nevertheless, RV ejection fraction of the Continuous Group remained lower than Intermittent Group for a longer period (72 hours versus 48 hours, p < 0.001). At rest, RV myocardial performance of the Continuous Group was significantly worse than Sham Group, after 72 hours and 96 hours of protocol (p < 0,039). Under dobutamine stress, Continuous Group presented worsening myocardial performance indexes, as compared to both Intermittent and Sham Group (p < 0.01). Regarding morphological analysis, both study groups presented an increased RV mass of similar magnitude, despite less exposure of Intermittent Group to pressure overload. Although both protocols of RV systolic overload had induced similar RV mass gain, intermittent systolic overload was more efficient in preserving RV myocardial performance in goats
622

Grandes déviations pour les temps locaux d'auto-intersections de marches aléatoires

Laurent, Clément 18 November 2011 (has links)
Dans cette thèse on s'intéresse au temps local d'auto-intersections de marches aléatoires. Cette quantité est définie comme la norme-p à la puissance p du temps local de la marche. Elle regarde dans quelle mesure la trajectoire de la marche aléatoire s'intersecte. Le temps local d'auto-intersections est lié à différents modèles physiques comme les modèles de polymères ou les problèmes d'écoulements de flux en milieux stratifiés mais aussi au modèle mathématiques des marches aléatoires en paysages aléatoires. Nous nous sommes pour notre part intéressés en particulier aux grandes déviations du temps local d'auto-intersections, c'est à dire que nous regardons la probabilité que la quantité d'intersections de la marche aléatoire soit plus grande que sa moyenne. Cette question qui a été très étudiée au cours des années 2000 fait apparaitre trois cas distincts, le cas sous-critique, le cas critique et le cas sur-critique. Nous améliorons la connaissance sur cette question au travers de deux résultats complets et d'un résultat partiel. D'abord nous prouvons un principe de grandes déviations dans les cas critique et sur-critique des marches alpha-stables, puis nous améliorons les échelles de déviations au cas sous-critique tout entier de la marche simple, enfin nous sommes en train d'étendre ce dernier résultat aux marches alpha-stables. Par ailleurs les trois preuves sont basées sur l'utilisation d'une version due à Eisenbaum d'un théorème d'isomorphisme de Dynkin. Cette méthode d'abord introduite par Castell dans le cas critique est donc ici étendue aux autres cas. Nous avons donc réussi à unifier les différentes méthodes de preuves au travers ce théorème d'isomorphisme. / In this thesis we are interested in the self-intersection local times of random walks. This quantity is defined as the p-norm to the power of p of the local times of the random walk. It measures how much the trajectory of the random walk intersects itself. The self-intersection local times is connected with various physical models as polymer models or problems of anomalous dispersion in layered random flows, but it is also linked with the mathematical model of random walks in random sceneries. More precisely, we are interested in the large deviations of the self-intersection local times, i.e. we work on the probability for the intersections to be larger than expected. This question that has been studied a lot during the 2000's is divided in three cases, the subcritical one, the critical one and the super critical one. We improve the knowledge about this question by two complete results and a partial one. First, we have proved a large deviation principle in the critical and super critical cases of alpha-stable random walks, then we have improved the deviations' scales to the entire subcritical case of simple random walk, finally we are extending this last result to the alpha-stable random walks. The three proofs are based on a version due to Eisenbaum of a Dynkin isomorphism theorem. This method which has been first introduced by Castell in the critical case, is extended here to the others cases. Thus, we have succeeded to unify the methods of proof by this isomorphism theorem.
623

Le groupe professionnel des managers de rayon en France : travail, emploi et ethos dans les grandes surfaces alimentaires / Department managers' professional group in french supermarkets and hypermarkets

Racine, Florent 30 November 2018 (has links)
Depuis une trentaine d’années, les travaux français qui portent sur les grandes surfaces alimentaires en sociologie du travail ont privilégié l’étude des caissières sans se soucier outre mesure des salariés des rayons. Cette thèse vise à rétablir ce déséquilibre en se focalisant sur les managers de rayon, premier niveau d’encadrement des magasins.Afin d’étudier ce groupe, nous commençons par mobiliser la sociologie du travail pour conduire une analyse microsociologique de leur travail quotidien. Les managers ont pour principales missions de faire progresser le chiffre d’affaires et la marge des rayons sous leur responsabilité ainsi que de motiver leurs équipes d’employés. Ils sont donc en interaction constante avec les employés chargés de la mise en rayon des produits, d’une partie des commandes et de la gestion des stocks, mais aussi avec d’autres interlocuteurs comme les fournisseurs ou encore les clients. Ce sont les membres de la direction du magasin (manager secteur, directeur) qui leur donnent des directives, contrôlent leurs résultats et évaluent leur comportement.Afin de prendre de la hauteur vis-à-vis des interactions quotidiennes, nous mobilisons également la sociologie des professions pour conduire une analyse davantage mésosociologique et macrosociologique. Nous étudions de cette façon les transformations de l’organisation du travail dans les magasins et celles du groupe des managers de rayon, toutes deux étroitement corrélées aux mutations structurelles de la branche de la distribution qui s’adapte en permanence aux aléas de la conjoncture économique et au goût versatile des consommateurs. Nous nous focalisons par conséquent sur les changements du travail, de l’emploi et de l’organisation des supermarchés et des hypermarchés qui touchent les managers depuis les années 2000 et s’accélèrent au cours des années 2010.Contrairement aux monographies réalisées sur les caissières, cette approche permet au moins deux choses. Premièrement, nous pouvons replacer dans leur contexte les nombreuses transformations du travail, de l’organisation et de l’emploi qu’ont vécues les salariés des rayons depuis le tournant des années 2010. Quand cela s’avère nécessaire, nous détaillons l’impact différencié de ces mutations sur les managers en fonction de leur appartenance à un ou plusieurs segments professionnels : enseigne intégrée vs indépendante, rayons alimentaires vs non alimentaires, zone urbaine vs rurale, supermarchés vs hypermarchés, faible présence syndicale vs délégués syndicaux revendicatifs.Notre approche nous permet par ailleurs de développer une réflexion dans le champ de la sociologie des professions : entre une approche fonctionnaliste qui se focalise sur l’unité d’une profession et une approche interactionniste qui insiste sur la diversité des pratiques au sein d’un même groupe professionnel, nous mobilisons le concept d’ethos professionnel pour penser à la fois l’unité et la diversité du groupe des managers de rayon. Nous proposons pour ce faire une définition personnelle de l’ethos en trois dimensions : une dimension pratique (activité, tâches, travail concret), une dimension symbolique (discours, normes, valeurs, représentations) et une dimension sociale (sexe, classe, race, diplôme, âge). Cet ethos ainsi défini articule les caractéristiques objectives d’un groupe professionnel avec ses valeurs et représentations et avec son travail concret.La thèse se divise en deux grandes parties. La première décrit la dimension pratique de l’ethos professionnel des managers de rayon. La seconde ajoute les dimensions symbolique et sociale de cet ethos bousculé par les récentes réorganisations des magasins. La thèse se conclut par une définition précise du concept d’ethos professionnel qui ouvre des perspectives de recherche concernant d’autres groupes professionnels. / For the past 30 years, research in France concerning workplace sociology within supermarkets and hypermarkets have highly favored the study of cashiers, thus disregarding the department employees. The aim of this dissertation is to restore this discrepancy by focusing on department managers who represent the first level of management in retail stores.In order to study this specific workforce, a focus on workplace sociology was initially necessary to advance a microsociological analysis of their daily work. The main tasks of department managers are to increase the turnover and the profits of the departments they are responsible for as well as keeping up the motivation of their teams. Therefore, they are interacting on a daily basis with the employees responsible for shelving, ordering, and stock managing products as well as dealing with suppliers and customers. Instructions are given by the store management i.e. store manager or sector manager, who also check the employees’ results and assess their behavior. To get some insight into the daily interactions in a supermarket, the sociology of professions was considered to produce a mesosociological and macrosociological analysis of the workplace and employment. This serves as a way to study the evolution in retail stores’ work structure as well as the changes in the particular group of department managers. Both are closely linked to the structural changes of the retail industry which is constantly adjusting to the contingencies of the economic context and the changeable desire of customers. Therefore, the mutations at work will be highlighted, for the employment and management in supermarkets and hypermarkets, which have impacted managers since the early 2000s ; a process that began accelerating around 2010.Unlike the numerous monographs that can be found on the topic of cashiers, this approach will focus on two elements. First, we will contextualize the structural and employment evolutions at work that retail employees have faced since the turn of the 2010s. We will elaborate, when needed, on the differentiated impact of these mutations on managers depending on their relation to one or several professional segments: food store chains vs. independent stores, food department vs. non-food departments, urban areas vs. rural areas, supermarkets vs. hypermarkets, weak union presence vs. strong union representation. In addition, this method leads to a deeper consideration on the sociology of professions: 1) a functionalist theoretical approach which focuses on the individuality of a profession and 2) an interactionist theoretical approach underlining the variety of practices within the same professional group. The concept of professional ethos is all the while used to encompass both the uniqueness and variety of department managers. A personal interpretation of this ethos will be developed revolving around 3 points: a practical dimension (practice, activities, tasks, rules, daily missions), a symbolic dimension (discourse, norms, values, representations) and a social dimension (gender, education, age, social category). This new definition of ethos, remaining consistent with the objective features of a professional group and its values, representation, and daily work, will open up new perspectives of research regarding other professional groups.This dissertation is divided into two parts. The first is dedicated to the practical dimension of the professional ethos of department managers. The second is devoted to the symbolic and social aspects of this work ethos which has been disturbed by the recent restructuring of retail stores. This thesis will conclude with an accurate definition of the concept of professional ethos which will contribute to understand other professional groups.
624

Etude du comportement mécanique de tôles en alliage de titane et des paramètres procédé dans les opérations d'emboutissage à hautes températures / Study of the mechanical behavior of titanium sheets alloys and process parameters in hot stamping operations

Sirvin, Quentin 06 September 2018 (has links)
Dans l'industrie aéronautique, les alliages de titane sont utilisés pour leur excellent comportement mécanique associé à une faible masse volumique. Ils sont largement employés sous forme de tôles dont la mise en forme peut se faire par le biais de trois procédés : à température ambiante par opération d'emboutissage, à très hautes températures (T≈900°C) par formage superplastique (SPF) et à des températures intermédiaires (T=730°C, 880°C) par formage à chaud (HF). Le projet repose sur le développement du procédé d'emboutissage à chaud d'une tôle d'alliage de titane Ti-6Al-4V en conditions isothermes à des températures inférieures à 700°C. Par conséquent, la détermination des paramètres procédés et matériaux constitue une étape importante pour la mise en œuvre de simulations numériques et contribue à la réussite des opérations d'emboutissage de pièces industrielles. Ces paramètres procédés sont liés à la vitesse du poinçon, aux efforts de serre-flan et au frottement induit entre le flan et l'outillage. Leur analyse a permis de déterminer deux niveaux de températures (400°C et 500°C) offrant une chute drastique du coût énergétique, en comparaison des procédés HF ou SPF, tout en conservant des niveaux d'allongement suffisants. Les paramètres matériaux influençant le comportement de l'alliage sont analysés et quantifiés. Ils peuvent être influencés par plusieurs mécanismes : élasticité, viscosité, anisotropie (Hill48, Barlat91) et nature de l’écrouissage (isotrope, cinématique). Dans cette étude, un modèle de comportement élasto-viscoplastique anisotrope, capable de considérer les trajets de chargement subis par la tôle lors de sa mise en forme, a été formulé pour les deux niveaux de température. L’implantation du modèle de comportement a été réalisée dans le code de calcul éléments finis Abaqus/Standard 6.14® interfacé avec le logiciel ZMAT®. Elle a permis d’une part des simulations d’emboutissage de profil Omega pour lesquelles des comparaisons avec les expériences ont été réalisées et d’autre part, des calculs sur une pièce de forme complexe. / In the aerospace industry, titanium alloys are used for their excellent mechanical behavior associated with low density. They are widely available in sheet form and the final shape can be obtained through three processes: at room temperature by stamping operation, at very high temperatures (T≈900°C) by superplastic forming (SPF) and at intermediate temperature (T=730°C, 880°C) by hot forming (HF). The project is based on the development of the hot stamping process of Ti-6Al-4V titanium alloy sheet under isothermal conditions at temperatures below than 700°C. Therefore, the determination of the process and material parameters constitutes an important stage for implementing the numerical simulation while contributing to the success of the stamping operation at the scale of an industrial part. The process parameters are related to the punch speed, the blank holder forces and the friction induced between the sheet and the tool. Their analysis allowed to determine two temperature levels (400°C et 500°C) leading a drastic drop in energy cost, compared to HF or SPF processes, while maintaining enough elongation levels. The material parameters influencing the behavior of the alloy are analyzed and quantified. They can be influenced by several mechanisms: elasticity, viscosity, anisotropy (Hill48, Barlat91) and nature of hardening (isotropic, kinematic). In this study, an anisotropic elasto-viscoplastic behavior model, able to consider the loading path undergone by sheet during forming, has been formulated for both temperature levels. The implementation of the behavior model is achieved in Abaqus/Standard 6.14® Finite Element code with the material library plugin ZMAT®. It enables, on the one hand, stamping numerical simulations of a simple shape Omega profile for which experimental comparisons were done, on the other hand, calculations on an industrial part with a complex shape.
625

Avaliação experimental do metabolismo energético em dois protocolos de sobrecarga sistólica do ventrículo direito / Experimental evaluation of energy metabolism in two right ventricle systolic overload protocols

Fernando Antibas Atik 16 March 2012 (has links)
Objetivo: Alterações do metabolismo energético tem sido identificadas em processos de hipertrofia miocárdica, sendo algumas consideradas benéficas, porém outras estão associadas a insuficiência cardíaca. O objetivo deste trabalho foi comparar a atividade de três enzimas do metabolismo energético em dois protocolos de sobrecarga sistólica do ventrículo direito (VD) num modelo experimental em cabritos. Métodos: 27 cabritos jovens foram divididos em três grupos: Sham (sem sobrecarga), Contínuo (sobrecarga sistólica constante) e Intermitente (4 períodos de 12 horas de sobrecarga sistólica, intercalados com 12 horas de descanso). Durante as 96 horas do protocolo, a sobrecarga sistólica foi ajustada a fim de atingir relação de pressão entre a aorta e o VD de 0,7. Medidas ecocardiográficas e hemodinâmicas foram realizadas antes e após o período de sobrecarga diariamente até o término do protoloco. Após o término do mesmo, os animais foram sacrificados a fim de obter dados morfológicos e a atividade máxima das enzimas Glicose 6 Fosfato Desidrogenase (G6PD), Hexoquinase (HK) e Lactato Desidrogenase (LDH). Resultados: Houve aumento de 92,1% e 46,5% nas massas do VD e septal no grupo Intermitente, respectivamente, quando comparado ao grupo Sham, enquanto que no grupo Contínuo houve incremento de 37,2% somente na massa septal. O VD e Septo dos grupos submetidos à sobrecarga sistólica contínua e intermitente do VD apresentaram um aumento discreto, porém significativo, do conteúdo de água (VD, p=0,0014; Septo, p=0,0004) em relação ao grupo Sham. Ao final do protocolo, foi observado um aumento significativo de 103,8% da espessura do VD no grupo Intermitente, comparado a um aumento de 38,4% do grupo Contínuo. Houve também dilatação ventricular significativa no grupo Contínuo ao longo do protocolo, quando comparado aos outros grupos (p<0,001). Piores índices de desempenho miocárdico ocorreram no grupo Contínuo no momentos 72 e 96 horas, quando comparados ao grupos Sham (P<0,039) e Intermitente (P<0,001). A razão da atividade máxima da G6PD do VD pelo VE revelou um aumento de 130,1% no grupo contínuo (p= 0,012) e de 39,8% no grupo Intermitente (p=0,764), quando comparados ao grupo Sham. O processo de hipertrofia aguda do VD não afetou a atividade enzimática da HK e LDH nos grupos estudados. Conclusões: Apesar de haver uma sobrecarga sistólica proporcionalmente menor no VD do grupo intermitente, a bandagem intermitente do TP promoveu maior hipertrofia do VD. A maior atividade da G6PD observada no grupo contínuo sugere maior produção de radicais livres via NADPH oxidase, haja vista que o ciclo das pentoses Fosfato incrementa a disponibilidade de NADPH citoplasmático, ocasionados pela maior demanda de um estímulo de sobrecarga miocárdica constante, um importante mecanismo de insuficiência cardíaca. Este estudo sugere que a preparação do ventrículo sub-pulmonar com a sobrecarga sistólica intermitente poderá proporcionar melhor resultado para a cirurgia de Jatene em dois estágios que a sobrecarga contínua / Objective: Altered energy metabolism has been identified in myocardial hypertrophy. Some processes are considered beneficial, whereas others are linked to heart failure. The purpose of this study was to compare the activity of three different energy metabolism enzymes in two different protocols of right ventricle (RV) systolic overload in young goats. Methods: 27 young goats were separated into three groups: Sham (no overload), Continuous (continuous systolic overload) and Intermittent (4 periods of 12-hour systolic overload, alternated with a 12-hour resting period). During a 96-hour protocol, systolic overload was adjusted to achieve a 0.7 RV / aortic pressure ratio. Echocardiographic and hemodynamic evaluations were performed before and after systolic overload every day postoperatively. After the study period, the animals were humanely killed for morphological and Glucose-6-phosphate dehydrogenase (G6PD), hexoquinase (HK) and lactate dehydrogenase (LDH) activity assessment. Results: There was a 92.1% and 46.5% increase in RV and septal masses of Intermittent group, respectively, as compared to Sham group, while Continuous systolic overload resulted in 37.2% increase of only septal mass. There was a small, but significant increase in water content in RV and septum of Intermittent and Continuous groups, as compared to Sham group (RV, p=0.0014; Septum, p=0.0004). At the end of protocol, it was observed a greater increase in RV thickness (103.8%) in Intermittent group, as compared to Continous group (38.4%). There was also a significant right ventricle dilatation in Continuos group along the protocol, as compared to the other groups (p<0.001). A worsening RV myocardial performance index occurred in the continuous group at 72 hours and 96 hours, compared with the sham (P<0.039) and intermittent groups (P<0.001). Compared to Sham, RV to LV G6PD activity ratio was elevated by 130.1% in Continuous group (p= 0,012) and by 39.8% in Intermittent group (p=0.764). The acute hypertrophic process in the RV did not altered the HK and LDH enzymatic activity among study groups. Conclusions: Despite of a proportional lesser exposure to systolic overload, intermittent pulmonary trunk banding promoted greater RV hypertrophy. This study indicates that continuous systolic overload for ventricle retraining causes upregulation and hyperactivity of myocardial G6PD. Since pentose phosphate pathway enhances cytosolic NADPH availability, this altered energy substrate metabolism can elevate levels of free radicals by NADPH oxidase, an important mechanism in the pathophysiology of heart failure. It suggests that Intermittent systolic overload may provide better results for 2-stage Jatene operation as compared to continuous protocol
626

Distribuição de autovalores de matrizes aleatórias. / Eigenvalues distribution of random matrices.

Roberto da Silva 18 May 2000 (has links)
Em uma detalhada revisão nós obtemos a lei do semi-círculo para a densidade de estados no ensemble gaussiano de Wigner. Também falamos sobre a analogia eletrostática de Dyson, enxergando os autovalores como cargas que se repelem no círculo unitário, mostrando que nesse caso a densidade de estados é uniforme. Em um contexto mais geral nós obtemos a lei do semicírculo, provando o teorema de Glivenko-Cantelli para variáveis fortemente correlacionadas usando um método combinatorial de contagem de trajetos, o que nos dá subsídios para falar em estabilidade da lei do semi-círculo. Também, nesta dissertação nós estudamos as funções de correlação nos ensembles gaussiano e circular, mostrando que sob um adequado reescalamento elas são idênticas. Outros ensembles nesta dissertação foram investigados usando o Método de Gram para o caso em que os autovalores são limitados em um intervalo. Computamos a densidade de estados para cada um desses ensembles. Mais precisamente no ensemble de Chebychev, os resultados foram obtidos analiticamente e nesse ensemble além da densidade de estados, também traçamos grá…cos da função de correlação truncada. / In a detailed review we obtain a semi-circle law for the density of states in theWigner’s Gaussian Ensemble. Also we talk about Dyson’s Analogy, seeing the eigenvalues like charges that repulse themselves in the unitary circle, showing that this case the density of states is uniform. In a more general context we obtain the semi-circle law, proving the Glivenko-Cantelli Theorem to strongly correlated variables, using a combinatorial method of Paths' Counting. Thus we are showing the stability of the semi-circle Law. Also, in this dissertation we study the correlation functions in the Gaussian and Circular ensembles showing that using the Gram's Method in the case that eigenvalues are limited in a interval. In these ensembles we computed the density of states. More precisely, in a Chebychev ensemble the results were obtained analytically. In this ensemble, we also obtain graphics of the truncated correlation function.
627

Grandes obras no Nordeste: o Projeto de Transposição das Águas do Rio São Francisco

Silva, Flávio José Rocha da 13 August 2015 (has links)
Made available in DSpace on 2016-04-26T14:55:34Z (GMT). No. of bitstreams: 1 Flavio Jose Rocha da Silva.pdf: 11685449 bytes, checksum: 499e0dc41d0630c401f4fb88b7b109ba (MD5) Previous issue date: 2015-08-13 / This research has its focus on the São Francisco River Diversion Project. This megaproject can be classified as the biggest development project in Brazil and follows other megaprojects that promised to develop the Northeast of Brazil. The methodology used in the work was the analysis of the justifications for other megaprojects in the Northeast in the last century and how those projects were appropriated by a few economic and political groups from that region in order to take advantage of public money. We believe that the discourse of "drought victims" used by those groups was successful in demanding money from the federal government to build water reservoirs and irrigation projects along with the creation of many governmental institutions, such as the SUDENE, to develop the Northeast. This discourse collaborated to benefit the Northeastern political elite and some economic groups from other parts of Brazil which profited with the construction of those projects. Our conclusion is that the model of development that has been in place in the last decades does not respect the social and environmental characteristics of the Northeast by creating a distance between the government megaprojects and the local population, in contrast with the actions developed by some non-governmental organizations since the eighties that prioritize the local environment with its limits and potentialities. The São Francisco River Diversion Project, publicized by the government as a Project that will provide water for more than 12 million people, reproduces the historical way to deal with the problems in the Northeast by affirming a model of development that degrades the environment and does not respect the reality of those who live in the Northeast. This project impacts the São Francisco River, which already suffers from many human actions of exploitation of its resources. It also impacts many indigenous and afro-descendants communities, fisher peoples and peasants who survive from the abundance of the river. In sum, we conclude that the São Francisco River Diversion Project will be added to a long list of megaprojects that brought benefits to a few while the majority will continue disadvantaged land and water concentrations, the real cause of the social inequality in the Northeast of Brazil / Este trabalho de pesquisa tem o seu foco no Projeto de Transposição das Águas do Rio São Francisco PTARSF para os estados do Nordeste Setentrional. O objeto pesquisado pode ser classificado como a maior obra hídrica já realizada no Brasil e está inserida no campo das grandes obras que prometem levar o desenvolvimento para o Nordeste brasileiro. Nossa apreciação metodológica pautou-se primeiramente pela análise das justificativas para os outros grandes projetos naquela mesma região no último século e de como estes foram apropriados por grupos econômicos e/ou políticos locais e de outras partes do país. Para isso, corroborou o discurso de vítimas da seca amplificado pela elite nordestina com o intuito de reivindicar verbas para a açudagem, os perímetros de irrigação, além da criação de vários órgãos que supostamente trariam o desenvolvimento para o Nordeste e principalmente para o Semiárido, a exemplo da SUDENE. Diante de tantas tentativas ao longo de mais de cem anos, o que teria dado errado? A nossa conclusão é que o modelo de desenvolvimento vendido como o propulsor de melhorias para aquela área do país não respeita as características do meio ambiente local, criando uma dissonância entre os megaprojetos e os habitantes daquele lugar, diferentemente dos vários projetos de convivência com o Semiárido, que surgiram a partir dos anos 1980. O PTARSF, vendido pela propaganda governamental como uma obra que levará água para 12 milhões de pessoas e o desenvolvimento para os estados que receberão as águas do São Francisco, está reproduzindo a lógica secular das grandes obras com gastos públicos para lucros privados, além de reproduzir e ampliar um padrão de desenvolvimento em desacordo com a realidade dos que habitam a área de sua realização. Ele afeta sobremaneira o Rio São Francisco, um manancial que já enfrenta problemas por causa de várias ações antrópicas. O PTARSF também atinge várias comunidades de povos indígenas, remanescentes quilombolas, vazanteiros, pescadores artesanais, etc. Em suma, concluímos que esta é mais uma grande obra para entrar na lista daquelas cuja existência trará benefícios para uns poucos em detrimento da grande maioria da população nordestina sem lidar com as estruturas de concentração agrária e hídrica, verdadeiras causas das desigualdades socioeconômicas do Nordeste
628

Polimorfismos de enzimas de fase 1 e 2 do metabolismo de drogas em pacientes portadores de linfoma difuso de grandes células B / Polymorphisms of phase 1 and 2 enzymes of drugs metabolism in patients with diffuse large B cell lymphoma

Souza, Pamela Oliveira de 27 June 2011 (has links)
Para avaliar a influência dos polimorfismos de nucleotídeo único (SNPs) do CYP2B6, CYP3A5, GSTM1, GSTP1, GSTT1, PON1, NQO1 e MDR1 na resposta ao tratamento com R-CHOP e CHOP, 82 pacientes com Linfoma Difuso de Grandes Células B, sem evidências de infecção por HIV, foram selecionados nesse estudo. Amostras de sangue periférico foram coletadas para extração de DNA. Os SNPs foram analisados por PCR-RFLP. Em relação aos pacientes que apresentaram resposta completa (RC) ao tratamento (70%), 51% foram tratados com R-CHOP. Sobre o tratamento, 50% dos pacientes com RC apresentaram classificação de ECOG 0-1 (p=0,0193) e a maioria desses pacientes (41%) não apresentaram envolvimento extranodal (p=0,0377). Não houve associação entre os SNPs do CYP2B6, CYP3A5, GSTT1, NQO1 e MDR1 (C3435T) e as variáveis estudadas. Apenas CYP3A5 (sexo p=0,0519), GSTM1 (idade p=0,016; tratamento p=0,0372), GSTP1 (envolvimento extranodal p=0,0307), PON1 (sintomas B p=0,0201; Bulky p=0,0148) e MDR1 C1236T (sexo p=0,0316) mostraram associação. Em relação à sobrevida global, apenas tratamento (p=0,0129), IPI (p=0,000342), idade (p=0,0155), estadiamento (p=0,00281) e ECOG (p=0,00869) apresentaram resultados significantes. Quanto à sobrevida livre de doença (SLD), apenas idade (p=0,0292), estadiamento (p=0,0402) e ECOG (p=0,0142) apresentaram resultados significantes / To evaluated the influence of single nucleotide polymorphisms (SNPs) of CYP2B6, CYP3A5, GSTM1, GSTP1, GSTT1, PON1, NQO1 and MDR1 in the treatment response with R-CHOP and CHOP, 82 patients with Diffuse Large B-cell Lymphoma, without evidence of HIV infection, were enrolled in this study. Peripheral blood samples were collected for DNA extraction. The SNPs were analyzed by PCR-RFLP. In relation the patients that showed complete response (CR) to the treatment (70%), 51% were treated with R-CHOP. About the treatment, 50% of the patients with CR showed ECOG classification of 0-1 and the most of these patients (41%) did not showed extranodal involvement (p=0,0377). There was no association between CYP2B6, CYP3A5, GSTT1, NQO1 and MDR1 (C3435T) SNPs and the variables studied. Only CYP3A5 (gender p=0,0519), GSTM1 (age p=0,016; treatment p=0,0372), GSTP1 (extranodal involvement p=0,0307), PON1 (B symptoms p=0,0201; Bulky p=0,0148) e MDR1 C1236T (gender p=0,0316) showed association. In relation to overall survival, only treatment (p=0,0129), IPI (p=0,000342), age (p=0,0155), stadiament (p=0,00281) and ECOG (p=0,00869) showed significant results. To disease-free survival, only age (p=0,0292), stadiament (p=0,0402) e ECOG (p=0,0142) showed significant results
629

Le décrochage universitaire : les facteurs d'intention, de santé mentale et de personnalité / Dropping out of university : factors of intention, mental health and personnality

Vinciguerra, Antony 30 January 2018 (has links)
Objectifs. Le décrochage d’études universitaires est un comportement marquant la sortie d’un cursus avant l’obtention du diplôme le validant. Il est produit par des processus complexes se manifestant sur les lignes de fragilité du rapport entre la singularité psychique de l’étudiant et le cursus d’études dans lequel il s’inscrit et évolue. Cette thèse vise à préciser les déterminants psychosociaux à l’œuvre dans ces processus. / Introduction. Dropping out of university is a behavior related to leaving a study course without a degree. It is produced by complex processes manifested on the lines of fragility in the relationship between the psychic singularity of the student and the enrollment on specific studies. The aim of this thesis is to precise psychosocial determinants at work in these processes.
630

Etude du méandrement du sillage éolien lointain dans différentes conditions de rugosité / Study of the meandering of the far wake of a wind turbine in various roughness conditions

Muller, Yann-Aël 10 December 2014 (has links)
Le phénomène connu sous l'appellation "méandrement" (ou meandering) désigne les variations aléatoires de la trajectoire du sillage aérodynamique d'une éolienne. Ce phénomène est responsable de contraintes mécaniques particulières sur les éoliennes positionnées dans le sillage d'autres éoliennes et joue donc rôle dans la conception et dans la prévision de production des parcs éoliens.Ce travail propose d'étudier le méandrement par des moyens expérimentaux et numériques. La problématique est traitée en deux parties, la première portant sur la modélisation de l'écoulement de couche limite atmosphérique, avec une attention particulière portée à la modélisation des grandes échelles de la turbulence atmosphérique. La seconde partie porte sur l'étude du sillage d'un disque actuateur soumis à un écoulement atmosphérique. Chacune de ces parties comporte un volet expérimental et un volet numérique. La modélisation numérique instationnaire de l'écoulement atmosphérique fait intervenir une technique de génération stochastique de champs de vitesse turbulente avec évolution temporelle, spécialement développée au cours de la présente thèse et à laquelle un chapitre spécifique est dédié.L'un des principaux résultats est que le méandrement du sillage est fortement corrélé avec les grandes échelles de la turbulence atmosphérique. / The phenomenon known as meandering describes the unsteady trajectory variations of the wake of a wind turbine. This phenomenon is responsible for specific mechanical stresses on turbines positioned in the wake of other turbines. As such, this phenomenon must be accounted for in the design and operation of wind turbine plants.This work uses numerical fluid simulation and wind tunnel testing in order to study the meandering of the wake of a wind turbine. The subject is discussed in two parts. The first part discusses the modeling of the atmospheric boundary layer, with a focus on the large scales of the atmospheric turbulence. The second part is a study of the behavior of the wake of an actuator disc model in atmospheric wind conditions.Both parts include experimental and numerical work. The numerical simulation of the atmospheric boundary layer involves the generation of synthetic turbulent velocity time series by mean of a stochastic technique developed during this thesis, to which a chapter is dedicated.One of the main results of this work is that the meandering is highly correlated with the large scales of the atmospheric turbulence.

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