Toxinas que atuam em canais para Na+ operados por voltagem são as principais responsáveis pelos efeitos tóxicos do envenenamento escorpiônico e podem ser divididas em duas classes: a- e b-neurotoxinas. TsTX-V e TsTX-I da peçonha de Tityus serrulatus (TsV) são, respectivamente, exemplos destas toxinas. Neste trabalho, foram avaliados os efeitos da TsV e destas toxinas sobre a pressão arterial média (PAM) e liberação de catecolaminas em ratos conscientes e não imobilizados, previamente cateterizados, bem como a captação de GABA, dopamina (DA) e glutamato (Glu) em sinaptosomas isolados de cérebro de ratos e a concentração citoplasmática de Ca+2 ([Ca+2 ]C) em células de músculo liso vascular de aorta de ratos. As toxinas foram isoladas por cromatografia de troca iônica (TsTX-I) seguida por CLAE de fase reversa (TsTX-V). As toxinas (15 e 30 g/kg) e TsV (50 e 100 g/kg) foram injetadas intravenosamente. A PAM foi monitorada continuamente através do cateter femoral. Os níveis plasmáticos de adrenalina (ADR) e noradrenalina (NA) foram determinados por CLAE de fase reversa com detector eletroquímico, em 10 min antes e 2,5, 30 e 90 min após os tratamentos. Efeitos pressores máximos foram observados em 2,5?3,5 min. TsV induziu um intenso aumento de longa duração na PAM, bem como a TsTX-I. A TsTX-V mostrou efeitos pressores menores. TsV mostrou os maiores efeitos sobre a liberação de catecolaminas, seguido pela TsTX-I e TsTX-V com um efeito máximo em 2,5 min, seguido por uma gradual redução, permanecendo, todavia, maior que os controles. Embora ambas as classes de toxinas atuem em canais para Na+, TsTX-I mostrou efeitos mais significantes e intensos sobre a liberação de catecolaminas e pressão arterial que a TsTX-V. Parece que a toxicidade da TsTX-V não está somente relacionada à sua capacidade de liberar catecolaminas, indicando que outros neutrotransmissores podem estar envolvidos em sua toxicidade. Nem a TsV ou suas toxinas foram capazes de afetar a captação de 3H-Glu. TsTXI inibiu somente a captação de 3H-DA (IC50 = 28,41 nM). Por outro lado, TsV (0,43ng/mL) inibiu a captação de 3H-GABA e 3H-DA (~50%). TsTX-V mostrou IC50 = 9,37 nM e 22,2 nM para a captação de 3H-GABA e 3HDA, respectivamente. Esses efeitos foram abolidos pelo pré-tratamento com TTX, indicando o envolvimento de canais para Na+ neste processo. Na ausência de Ca+2 e em baixas concentrações de toxinas, a redução não é tão singnificante como na presença de Ca+2. TsTX-V não reduziu a captação de 3H-GABA em células COS-7 expressando os transportadores de GABA, GAT-1 e GAT-3, sugerindo que esta toxina reduz indiretamente o transporte. A redução da captação de 3H-GABA pelos sinaptosomas pode ser devido a rápida e intensa despolarização celular, como revelado por microscopia confocal em células de glioma C6. Assim, TsTX-V causou redução da captação de 3H-GABA e 3H-DA de uma maneira independente de Ca+2, não afetando diretamente os transportadores de GABA, mas em consequencia da despolarização, envolvendo canais para Na+ operados por voltagem. TsV e suas toxinas foram capazes de aumentar a ([Ca2+ ]C , provavelmente por interargir com canais para Na+. Quando comparado aos efeitos despolarizantes do KCl 60 mM (100 %), TsV (100 e 500 g/mL) exibiu um aumento de 49,60 ± 2,58 % e 103,66 ± 5,17 %, respectivamente, enquanto que a TsTX-I e TsTX-V (50 e 100 g/mL de cada) exibiu 43,92 ± 3,06 % e 121,8 ± 8,9 %; 52,56 ± 8,33 % e 79,5 ± 6,1 % de aumento, respectivamente. TsTX-I (100 g/mL) mostrou-se mais potente nesta preparação, visto que uma dose de 100 g/mL causou efeito muito mais intenso do que a TsTX-V na mesma concentração. É possível que as diferenças observadas sobre os efeitos induzidos pela TsTX-I e TsTX-V sejam conseqüência de alterações estruturais entre canais para Na+ presentes em vários tipos de tecidos e inervações. / Voltage-gated Na+ channel toxins are mainly responsible for the toxic effects of scorpion envenoming and can be classified into two classes: a- and b-neurotoxins. TsTX-V and TsTX-I from Tityus serrulatus venom (TsV) are, respectively, examples of these toxins. In this work, were evaluate the effects of TsV and its toxins on mean arterial pressure (MAP) and catecholamines release in conscious unrestrained rats previously catheterized, as well as GABA, dopamine (DA) and glutamate (Glu) uptake in isolated rat brain synaptosomes and cytosolic Ca2+ concentration ([Ca2+ ]C) in vascular smooth muscle cells from rat aorta. Toxins were isolated by ion exchange chromatography (TsTX-I) followed by RP-HPLC (TsTX-V). The toxins (15 and 30 g/kg) and TsV (50 and 100 g/kg) were injected intravenously. MAP was continuously monitored through femoral catheter. Epinephrine (E) and norepinephrine (NE) plasma levels were determined by RP-HPLC with electrochemical detection, at 10 min before and 2.5, 30 and 90 min after treatments. Maximal pressor effects were observed at 2.5 3.5 min. TsV induced intense long lasting increase in MAP, as did TsTX-I. TsTX-V showed the lowest pressor effects. TsV showed the highest effects on catecholamines release, followed by TsTX-I and TsTX-V with maximal effect at 2.5 min, followed by a gradual reduction, however remaining higher than controls. Although both toxins act on Na+ channels, TsTX-I displayed significant and more intense effects on catecholamines release and blood pressure than TsTX-V. It seems that the toxicity of TsTX-V is not related only with its ability to release catecholamines, indicating that other neurotransmitters, may be involved in its toxicity. Neither the TsV or its toxins was capable to affect the 3H-Glu uptake. TsTX-I inhibited only 3H-DA uptake (IC50 = 28.41 nM). On the other hand, TsV (0.43ng/mL) inhibited both 3H-GABA and 3H-DA uptake (~50%). TsTX-V showed IC50 = 9.37 nM and 22.2 nM for 3H-GABA and 3H-DA uptake, respectively. These effects were abolished by pre-treatment with TTX, indicating the involvement of Na+ channels in this process. In the absence of Ca2+ and at low concentrations of toxin, the reduction is not as significant as in the presence of Ca2+. TsTX-V did not reduce 3H-GABA uptake in COS-7 cells expressing GABA transporters GAT-1 and GAT-3, suggesting that this toxin indirectly reduces the transport. The reduced 3H-GABA uptake by synaptosomes could be due to fast and intense cell depolarization as revealed by confocal microscopy of C6 glioma cells. Thus, TsTX-V causes reduction on 3H-GABA and 3H-DA uptake in a Ca2+-independent manner, not affecting directly GABA transporters, but, in consequence of depolarization, involving voltage-gated Na+ channels. TsV and its toxins were able to increase the ([Ca2+ ]C , probably by interact with Na+ channels. When compared to KCl 60 mM depolarizing effect (100 %), TsV (100 and 500 ?g/mL), showed an increase of 49.60 ± 2.58 % and 103.66 ± 5.17 %, respectively, whereas TsTX-I and TsTX-V (50 and 100?g/mL of each) showed 43.92 ± 3.06 % and 121.8 ± 8.9 %; 52.56 ± 8.33 % and 79.5 ± 6.1 %, respectively. TsTX-I (100 ?g/mL) showed most potent effects in this type of preparation, since induced most intense effect that TsTX-V in the same concentration. Thus, it is possible that the differences observed on the effects induced by both toxins are consequence of structural changes among Na+ channels present in several types of tissues and innervations .

O relaxamento vascular induzido pelo óxido nítrico (NO) está prejudicado em aorta de ratos hipertensos renais (2R-1C). A nossa hipótese é de que o menor efeito do NO na aorta de ratos 2R-1C pode estar relacionada com a maior degradação do NO e/ou modificação das cavéolas no músculo liso vascular (MLV), considerando que o NO pode ser degradado rapidamente e que as cavéolas parecem ser importantes para a redução da concentração citosólica de Ca2+ ([Ca2+]c). O presente trabalho teve por objetivo estudar as alterações nos mecanismos vasodilatadores do NO em aorta de ratos hipertensos renais 2R-1C. Inicialmente, estudamos a influência do estresse oxidativo sobre o efeito do NO liberado dos doadores [Ru(NH.NHq)(terpy)NO+]3+ (TERPY) e nitroprussiato de sódio (NPS) em aorta de ratos normotensos (2R) e 2R-1C. Verificamos que o relaxamento foi menor na aorta dos ratos 2R-1C do que de 2R para o TERPY e NPS e que nas células do MLV da aorta de 2R-1C o efeito do TERPY em reduzir a [Ca2+]c também foi menor. Porém, o tratamento das aortas de ratos 2R-1C com antioxidante normalizou o relaxamento para ambos doadores e o efeito do TERPY sobre a [Ca2+]c. A concentração basal de superóxido (O2-) nas aortas dos ratos 2R-1C é maior do que em 2R e foi reduzida pelos antioxidantes. A concentração de NO basal e liberada do TERPY é menor em aortas de ratos 2R-1C. Estudamos a influência das cavéolas sobre o efeito do TERPY e NPS, em aorta de ratos 2R e 2R-1C. Somente em aortas de ratos 2R, a desorganização das cavéolas com ciclodextrina inibiu o relaxamento dos doadores de NO utilizados e a redução da [Ca2+]c para o TERPY. O número de cavéolas é menor tanto nas células do MLV como nas células endoteliais da aorta de ratos 2R-1C. Estudamos ainda o efeito do TERPY sobre a pressão arterial de ratos 2R e 2R-1C acordados. O TERPY possui efeito hipotensor somente nos ratos 2R-1C e este efeito foi mais prolongado do que o efeito hipotensor com NPS. O NPS teve efeito hipotensor tanto em ratos 2R como 2R-1C, porém este efeito foi maior em 2R-1C. Os resultados obtidos neste estudo indicam que a elevada concentração de O2- e o menor número de cavéolas encontrados na aorta dos ratos 2R-1C, devem contribuir de forma importante para o menor relaxamento da aorta de ratos 2R-1C. / The vascular relaxation induced by nitric oxide (NO) donors is impaired in aortas from renal hypertensive rats (2K-1C). Our hypothesis was that the lower NO effect in aortas from 2K-1C rats could be related with the higher degradation of NO and/or caveolae changes in vascular smooth muscle cells (VSMCs), considering that NO can be rapidly degraded and caveolae seems to play important role in the reduction of cytosolic Ca2+ concentration [Ca2+]c. The present study aimed to investigate the alterations on aorta relaxation induced by NO in 2K-1C rat aorta. At first, we studied the influence of oxidative stress on the effect of NO released from the NO donors [Ru(NH.NHq)(terpy)NO+]3+ (TERPY) and sodium nitroprusside (SNP) in aortas from normotensive (2K) and 2K-1C rats. The relaxation induced by both NO donors was impaired in aortas from 2K-1C rats and the reduction on [Ca2+]c induced by TERPY was also impaired in 2K-1C VSMCs. However, in aortas treated with antioxidants the relaxation to both NO donors and the reduction on [Ca2+]c to TERPY were normalized. The basal concentration of superoxide (O2-) was greater in 2K-1C than in 2K, which was reduced by the antioxidants. The basal cytosolic NO concentration ([NO]c) and the NO released from TERPY were lower in aortas from 2K-1C rats. We studied the influence of caveolae on the effects of NO released from the NO donors, in aortas from 2K and 2K-1C rats. We verified that caveolae disassemble with ciclodextrin impaired the relaxation to NO donors and the reduction on [Ca2+]c to TERPY only in aortas from 2K rats. The number of caveolae is reduced in aortic VSMCs and in the endothelial cells from 2K-1C rats. We studied the effect of TERPY on arterial pressure from 2K and 2K-1C rats. TERPY reduced the arterial pressure only in 2K-1C rats, which effect was longer than that produced by SNP. The hypotensive effect of SNP was greater in 2K-1C than in 2K rats. Taken together, our results indicate that the higher concentration of O2- and the reduced number of caveolae on aortas from 2K-1C rats could contribute to impaired aorta relaxation of 2K-1C rats.

Ancoragens são muito utilizadas na estabilização do maciço rochoso pela rapidez e baixo custo, embora sua análise não seja completamente entendida devido à interação de diferentes materiais como rocha, graute e aço. Este documento apresenta os resultados de um estudo realizado em juntas lisas reforçadas com ancoragens. Foram ensaiadas ancoragens com barras de diferentes diâmetros e diferentes orientações em relação ao plano da descontinuidade. Os ensaios realizados para avaliar o comportamento deste tipo de reforço foram o ensaio de arrancamento em tubo duplo e o ensaio de cisalhamento em juntas lisas reforçadas. Os ensaios de arrancamento em tubo duplo demonstraram que a resistência ao arrancamento é dependente da resistência à tração da barra. As deformações internas no sistema foram idealizadas através da obtenção de um comprimento livre hipotético de uma barra livre submetida a tração. Nos ensaios de cisalhamento, avaliou-se a melhora da resistência ao cisalhamento de descontinuidades lisas reforçadas com barras ancoradas. Observaram-se dois picos de carga mobilizada antes da ruptura do sistema no caso de barras perpendiculares ao plano da descontinuidade. Este fato introduz significativa ductilidade ao sistema e é importante do ponto de vista de confiabilidade do sistema. A ruptura das ancoragens se produz devido a uma combinação de efeitos de tração, flexão, e cortantes. Os sistemas reforçados com áreas maiores de aço apresentaram maior ductilidade, e, portanto oferecem maior segurança. Os resultados sugerem que uma vez superado o comprimento mínimo ancorado a ruptura das ancoragens acontecerá por ruptura das barras de aço e não por aderência na interface barra-graute, concluindo-se que a resistência das ancoragens é dependente da resistência de ruptura e da área de aço utilizada. Finalmente, esta pesquisa contribui ao entendimento dos mecanismos de ruína que acontecem num maciço reforçado com ancoragens. / Rock anchors are widely used to stabilize rock masses due to their rapid installation and low cost. Their behavior is not fully understood because of the interaction of different elements such as rock, grout and steel. This document presents the results of both pull-out and shear tests on steel bar reinforced discontinuities. Tests were carried out with different diameters and orientations of bars with respect to the discontinuity plane. Double-pipe pullout tests and smooth-joint anchor-reinforced shear tests were performed. The results of double-pipe pull-out tests were analyzed in terms of both strength and deformations. Internal strains were idealized through a model based on hypothetical length of a free bar. In the smooth-joint anchor-reinforced shear tests, both increase in shear strength and ductility were evaluated. Two load peaks were observed in test with bars perpendicular to the joint plane. Ductility is significantly increased with respect to joints reinforced with inclined bars. This is important for reliability evaluation. The failure of anchors is produced by a combination of tensile, bending, and shear internal forces. The systems reinforced with a greater amount of steel presented more ductile behavior than those less reinforced. The results suggest that since the minimum anchor length is exceeded, the system failure is governed by the rebar failure and not by the adhesion in the rebar-grout interface. From this, it is concluded that the anchor strength is dependent on the strength and cross section area of the rebar. Finally, this research contributes to better understanding of the failure mechanisms of anchor-reinforced rock masses.

Avec en perspective l’application à la robotique ou à l’étude des milieux granulaires, nous discutons la formulation des problèmes de contacts avec frottement en dynamique et pour les systèmes constitués de solides rigides. L’approche usuelle est event driven et ne permet pas d’écrire de manière systématique un problème d’évolution. Ceci a motivé l’émergence d’une nouvelle approche dans le cas sans frottement que nous généralisons au cas avec frottement. Suivant le point de vue de Lagrange sur l’équation de la dynamique, nous mettons en exergue l’usage systématique des puissances virtuelles et de la dualité. Ce parti-pris suggère de mettre l’accent sur l’effort généralisé de réaction dans la formulation et non sur les forces de réactions locales dans le monde réel, comme il est usuel. Ce point de vue permet d’échapper à des pathologies connues sous le nom de paradoxe de Painlevé. / In the view of robotics or granular media mechanics, we question the statement of the dynamical evolution problem for multibody systems with contacts and friction. The usual approach is event driven and does not allow to state an evolution problem in a systematic way. This matter of fact gave rise to a new approach in the frictionless case we generalize to the case with friction. Sticking to the point of view of Lagrange on the equation of the dynamics, we emphasize the systematic use of virtual powers and duality. This bias suggests to put emphasis on generalized reaction forces in the statement of the evolution problem and not on local reaction forces of the real world, as it is usual in practice. This point of view allows to escape from pathologies known as Painlevé paradox.

Thesis Across the Line of the World: On Poetics of Being on the Road in the Central and East European Novel of the second half of the Twentieth Century dissert on the phenomen of vagabondism in a given space and time. Analysis of eight texts (Albahari, Bachmannová, Bernhard, Bondy, Chwin, Miłosz, Müllerová, Sebald, Velikić) through the concept of smooth and striated space (Gilles Deleuze, Félix Guattari), and Milan Balaban's exegesis on the Biblical Exodus shows four basic principals of this rather intensive than extensive vagabondism: nothingness, sense for smoothness, melancholy and fragmentarization. Central and East European Novel Vagabondism Smooth and striated space (Gilles Deleuze, Félix Guattari) Exodus (Milan Balabán) Melancholy Nothingness Sense for smoothness Fragmentarization

Dans le premier chapitre de cette thèse, nous passons en revue les outils de la théorie analytique des nombres qui seront utiles pour la suite. Nous faisons aussi un survol des entiers y−friables, c’est-à-dire des entiers dont chaque facteur premier est plus petit ou égal à y. Au deuxième chapitre, nous présenterons des problèmes classiques de la théorie des nombres probabiliste et donnerons un bref historique d’une classe de fonctions arithmétiques sur un espace probabilisé. Le problème de Erdos sur la table de multiplication demande quel est le nombre d’entiers distincts apparaissant dans la table de multiplication N × N. L’ordre de grandeur de cette quantité a été déterminé par Kevin Ford (2008). Dans le chapitre 3 de cette thèse, nous étudions le nombre d’ensembles y−friables de la table de multiplication N × N. Plus concrètement, nous nous concentrons sur le changement du comportement de la fonction A(x, y) par rapport au domaine de y, où A(x, y) est une fonction qui compte le nombre d’entiers y− friables distincts et inférieurs à x qui peuvent être représentés comme le produit de deux entiers y− friables inférieurs à p x. Dans le quatrième chapitre, nous prouvons un théorème de Erdos-Kac modifié pour l’ensemble des entiers y− friables. Si !(n) est le nombre de facteurs premiers distincts de n, nous prouvons que la distribution de !(n) est gaussienne pour un certain domaine de y en utilisant la méthode des moments. / The object of the first chapter of this thesis is to review the materials and tools in analytic number theory which are used in following chapters. We also give a survey on the development concerning the number of y−smooth integers, which are integers free of prime factors greater than y. In the second chapter, we shall give a brief history about a class of arithmetical functions on a probability space and we discuss on some well-known problems in probabilistic number theory. We present two results in analytic and probabilistic number theory. The Erdos multiplication table problem asks what is the number of distinct integers appearing in the N × N multiplication table. The order of magnitude of this quantity was determined by Kevin Ford (2008). In chapter 3 of this thesis, we study the number of y−smooth entries of the N × N multiplication. More concretely, we focus on the change of behaviour of the function A(x,y) in different ranges of y, where A(x,y) is a function that counts the number of distinct y−smooth integers less than x which can be represented as the product of two y−smooth integers less than p x. In Chapter 4, we prove an Erdos-Kac type of theorem for the set of y−smooth integers. If !(n) is the number of distinct prime factors of n, we prove that the distribution of !(n) is Gaussian for a certain range of y using method of moments.

Cette thèse de doctorat composée de trois chapitres contribue au développement de la problématique sur la sélection de modèle de volatilité de type GARCH. Le premier chapitre propose une étude de simulation sur la sélection de modèles dans le cadre spécifique des modèles à changement de régimes. On propose des expériences de simulation permettant de mettre en évidence l'inefficacité des critères de sélection usuels dans des cas particuliers, ce qui peut conduire à des erreurs de spécification lors du choix de modèle. Le deuxième chapitre propose un test du multiplicateur de Lagrange de mauvaise spécification dans les modèles GARCH univariés. L'hypothèse nulle admet que le processus générateur des données est un modèle GARCH linéaire tandis que sous l'hypothèse alternative il correspond à une forme fonctionnelle inconnue qui est linéarisée à l’aide d’un développement de Taylor. On illustre le test dans une application empirique sur les taux de change. Le dernier chapitre étudie l'impact du prix du pétrole sur les spreads de Credit Default Swaps souverains de deux pays exportateurs de pétrole: le Vénézuela et la Russie. Utilisant des données récentes, nous trouvons que les rendements du prix du pétrole impactent les spread de CDS souverains du Vénézuela directement alors que cela passe par le canal du taux de change pour la Russie. Ce chapitre emploie des méthodes statistiques avancées, notamment l'utilisation de modèles à changement de régimes Markoviens. Finalement, l'appendice propose le manuel de la toolbox MSGtool (Matlab) qui propose une collection de fonctions pour l'étude des modèles à changement de régimes Markoviens. La toolbox est très user-friendly. / This Ph.D. thesis composed by three chapters contributes to the development of model selection in GARCH-type models.The first chapter investigates whether the most common selection criteria lead to choose the right specification in a regime switching framework. We propose simulation experiments which reveal the inefficiency of some selection criteria in particular cases which lead to misspecification. Depending on the Data Generating Process used in the experiments, great care is needed when choosing a criterion.In the second chapter, a misspecication test for GARCH-type models is presented. We propose a Lagrange Multiplier type test based on a Taylor expansion to distinguish between (G)ARCH models and unknown nonlinear GARCH-type models. This test can be seen as a general misspecication test. We investigate the size and the power of this test through Monte Carlo experiments. We show the usefulness of our test with an illustrative empirical example based on daily exchange rate returns.In the third chapter, we study the impact of oil price returns on sovereign Credit Default Swaps (CDS) spreads for two major oil producers, Russia and Venezuela. Using daily spreads from 2008 to 2015, we find that crude oil price returns are a critical determinant of Venezuela CDS spreads changes, but does not explain significantly Russian CDS spreads. Indeed, oil prices seem to impact Russian CDS spreads through the exchange rates canal. Finally, we propose as an appendix the manual of the MSGtool, a MATLAB toolbox, which provides a collection of functions for the simulation and estimation of a large variety of Markov Switching GARCH (MSG) models.

Cette thèse étudie les performances du marché du travail dans une économie susceptible de présenter plusieurs équilibres, et les implications d’une telle configuration pour la politique économique. Elle comporte quatre essais, traitant chacun d’un aspect spécifique de cette problématique. En premier lieu, l’analyse économétrique des séries temporelles de taux de chômage de quelques pays de l’OCDE, permettant notamment l’identification des changements de régimes et de leurs caractéristiques, apporte des évidences significatives à l’appui de l’hypothèse d’une multiplicité d’équilibres. En second lieu, on étudie les effets de l’introduction d’un salaire minimum obligatoire et d’une hausse de celui-ci dans un modèle statique de concurrence imparfaite avec négociations salariales au niveau de la firme, le facteur travail étant hétérogène. Si la hausse du salaire minimum est défavorable à l’emploi,l’introduction d’un salaire minimum en présence d’une multiplicité d’équilibres permet d’éliminer l’équilibre Pareto-inférieur. En troisième lieu, on étudie également les implications de l’existence d’équilibres multiples pour les politiques économiques, du fait de l’altération des propriétés dynamiques de l’économie, à travers l’analyse complète d’un modèle dynamique de concurrence imparfaite avec des négociations salariales individuelles et des frictions d’appariement sur le marché du travail. Enfin, on montre grâce à l’outil expérimental dans quelle mesure l’introduction d’une variable dite de tâche solaire, peut être source de défaut de coordination et d’inefficience dans une économie possédant deux équilibres Pareto-ordonnés. / This thesis analyzes the performances of labor market in an economy subject to multiple equilibria and the implications of such a configuration for economic policy. It contains four pieces of research, each dealing with a particular aspect of the general setting. First, the econometric analysis of the unemployment time series for several OECD countries,which allows the identification of regime switches and their characteristics, brings forth some significant evidence that the multiple equilibria framework is relevant. Second, the effect of the implementation and of the rise of the minimum wage are investigated through a static model, assuming imperfect competition, heterogeneous labor input and wage negotiations at the firm level. Though minimum wage hikes have an adverse effect on employment, the implementation of a binding minimum wage turns out to be an efficient tool for excluding the Pareto- inferior equilibrium. Third economic policy conditions are also affected because the existence of multiple equilibria alters the dynamic properties of the economy. This case has been investigated in the framework of a fully dynamic model assuming imperfect competition individual wage negotiations and matching frictions. Finally, a coordination game experiment confirms that the introduction of a sunspot can be a source of coordination failure and inefficiency in an economy with two Pareto-ranked equilibria.

Cette thèse se consacre aux garanties de reconstruction et de l’analyse de sensibilité de régularisation variationnelle pour des problèmes inverses linéaires bruités. Il s’agit d’un problème d’optimisation convexe combinant un terme d’attache aux données et un terme de régularisation promouvant des solutions vivant dans un espace dit de faible complexité. Notre approche, basée sur la notion de fonctions partiellement lisses, permet l’étude d’une grande variété de régularisations comme par exemple la parcimonie de type analyse ou structurée, l’anti-Parcimonie et la structure de faible rang. Nous analysons tout d’abord la robustesse au bruit, à la fois en termes de distance entre les solutions et l’objet original, ainsi que la stabilité de l’espace modèle promu.Ensuite, nous étudions la stabilité de ces problèmes d’optimisation à des perturbations des observations. A partir d’observations aléatoires, nous construisons un estimateur non biaisé du risque afin d’obtenir un schéma de sélection de paramètre. / This thesis is concerned with recovery guarantees and sensitivity analysis of variational regularization for noisy linear inverse problems. This is cast as aconvex optimization problem by combining a data fidelity and a regularizing functional promoting solutions conforming to some notion of low complexity related to their non-Smoothness points. Our approach, based on partial smoothness, handles a variety of regularizers including analysis/structured sparsity, antisparsity and low-Rank structure. We first give an analysis of thenoise robustness guarantees, both in terms of the distance of the recovered solutions to the original object, as well as the stability of the promoted modelspace. We then turn to sensivity analysis of these optimization problems to observation perturbations. With random observations, we build un biased estimator of the risk which provides a parameter selection scheme.

Nous avons déterminé la capacité de régénération du tissu vasculaire in vivo des CSM traitées avec BMP2 à la dose de [100 ng.mL-1] dans un modèle rat. Nous avons ainsi rapporté qu’une prothèse revêtue de CSM traitée par BMP2 pendant 1 semaine et implantée 14 jours chez le rat permettait la reconstitution des trois tuniques de la paroi mimant la structure de l’aorte. La capacité proangiogénique des CSM était augmentée par BMP2 grâce à la mise en jeu de voies intracellulaires impliquant le facteur induit par l’hypoxie (HIF-1α) via JAK/STATs. Nous avons montré que les CSM migraient sous l’influence de BMP2 par stimulation de l’activité du complexe enzymatique NADPH oxydase via l’augmentation de l’expression des protéines PAK1, Vav2 et RAC1 GTPase/PI3K. Ce travail a confirmé l’intérêt de l’utilisation de CSM conjointement à rh-BMP2, une protéine impliquée dans l’embryogénèse vasculaire, pour la bioingénierie de la régénération vasculaire. / We determined the capacity to regenerate vascular tissue in vivo, of MSC treated with BMP2 at a dose of [100 ng.mL-1] in a rat model. We have reported that a prosthesis coated with CSM treated 1 week with BMP2 and implanted in rats 14 days allowed the reconstruction of the three tunics of the wall that mimic the structure of the aorta. The proangiogenic capacity of MSCs was increased by BMP2 through the intracellular pathways involving hypoxia inducible factor (HIF-1α) via JAK / STAT. We have shown that MSCs migrated under the influence of BMP2 by stimulating the activity of the enzyme complex NADPH oxidase via the increased expression of PAK1 protein, Vav2 and RAC1 GTPase/PI3K. This work confirmed the interest of the use of MSC in conjunction with rh-BMP2, a protein involved in vascular embryogenesis for bioengineering for vascular regeneration.