Un automorphisme (extérieur) $phi $ d'un groupe libre $F_n$ de rang fini $ngeq 2$ est dit géométrique s'il est induit par un homéomorphisme d'une surface. La question à laquelle nous intéressons est la suivante: Quels sont les automorphismes de $F_n$ qui sont géométriques?Nous donnons une réponse algorithmique pour la classe des automorphismes à croissance polynomiale (en s'autorisant à remplacer un automorphisme par une puissance).Pour cela, nous sommes amenés à étudier les automorphismes de graphes de groupes. En particulier, nous introduisons deux transformations élémentaires d'automorphismes de graphes de groupes: les quotients et les éclatements.Pour le cas particulier où l'automorphisme est un twist de Dehn partiel, on obtient un critère pour décider quand un tel twist de Dehn partiel est un véritable twist de Dehn.En appliquant le critère à plusieurs reprises sur un twist de Dehn cumulé, nous montrons que soit on peut ＂déplier＂ ce twist de Dehn cumulé jusqu'à obtenir un twist de Dehn ordinaire, soit que $phi$ est à croissance au moins quadratique (et par conséquent, n'est pas géométrique).Cela montre, au passage, que tout automorphisme du groupe libre à croissance linéaire admet une puissance qui est un twist de Dehn. Ce fait est connu des experts, et souvent utilisé, bien qu'il n'en existait pas de preuve formelle dans la littérature (à la connaissance de l'auteur).Pour conclure, on applique l'algorithme de Cohen-Lustig pour le transformer en twist de Dehn efficace, puis on applique l'algorithme Whitehead et des théorèmes classiques de Nielsen-Baer et Zieschang pour construire un modèle géométrique ou pour montrer qu'il n'est pas géométrique. / An automorphism $phi$ of a free group $F_n$ of finite rank $n geq 2$ is said to be geometric it is induced by a homeomorphism on a surface.In this thesis we concern ourselves with answering the question:Which precisely are the outer automorphisms of $F_n$ that are geometric?to which we give an algorithmical decision for the case of polynomially growing outer automorphisms, up to raising to certain positive power.In order to realize this algorithm, we establish the technique of quotient and blow-up automorphisms of graph-of-groups, which when apply for the special case of partial Dehn twist enables us to develop a criterion to decide whether the induced outer automorphism is an actual Dehn twist.Applying the criterion repeatedly on the special topological representative deriving from relative train track map, we are now able to either “unfold” this iterated relative Dehn twist representative level by level until eventually obtain an ordinary Dehn twist representative or show that $hat{phi}$ has at least quadratic growth hence is not geometric.As a side result, we also proved that every linearly growing automorphism of free group has a positive power which is a Dehn twist automorphism. This is a fact that has been taken for granted by many experts, although has no formal proof to be found in the literature.In the case of Dehn twist automorphisms, we then use the known algorithm to make the given Dehn twist representative efficient and apply the Whitehead algorithm as well as the classical theorems by Nielsen, Baers, Zieschangs and others to construct its geometric model or to show that it is not geometric.

L’hypertension artérielle chronique induit une hypertrophie ventriculaire gauche, à l’origine d’une dysfonction diastolique caractérisée par des troubles de la relaxation, de la compliance et du remplissage ventriculaires gauches, le tout aggravé par toute augmentation de la fréquence cardiaque. Le couplage contraction-relaxation physiologique implique, en cas de préservation dans ce contexte d’hypertrophie ventriculaire gauche, que cette dysfonction diastolique s’accompagne d’une dysfonction systolique. Ainsi, ce travail de thèse s’est attaché (1) à caractériser la fonction ventriculaire gauche et le couplage contraction-relaxation à l’aide de la mesure de la torsion et la détorsion, (2) à étudier les mécanismes cellulaires impliqués dans le couplage contraction-relaxation et (3) à explorer les effets d’une stratégie thérapeutique visant à réduire la fréquence cardiaque sur la torsion et la détorsion du ventricule gauche dans un modèle d’hypertension artérielle chronique et d’hypertrophie ventriculaire induites chez le porc chroniquement instrumenté par la perfusion continue d’angiotensine II pendant 28 jours. A J28, la torsion et la détorsion étaient diminuées et la détorsion également retardée au sein du cycle cardiaque, alors que la fraction d’éjection ventriculaire gauche était préservée. Le couplage contraction-relaxation était préservé, tant au niveau du ventricule gauche qu’à l’échelon cardiomyocytaire, suggérant que toute dysfonction diastolique devrait faire rechercher une dysfonction systolique. A J28, ces anomalies fonctionnelles s’accompagnaient d’une diminution de l’expression de la SERCA2a et de sa protéine régulatrice le phospholamban. Des anomalies du récepteur de la ryanodine de type 2 étaient aussi observées avec son hyperphosphorylation et la dissociation de sa protéine régulatrice calstabine 2, à l’origine de fuites calciques systoliques et diastoliques. Ce dernier pourrait ainsi jouer un rôle clé dans la préservation du couplage contraction-relaxation et représenter l’intégrateur entre les anomalies ventriculaire gauche systolique et diastolique observées. Enfin, la réduction pharmacologique de la fréquence cardiaque à J28 par l’ivabradine, un inhibiteur sélectif des canaux If, permettait d’améliorer, en partie par des effets fréquence-indépendants dont les mécanismes cellulaires restent à élucider, tant les anomalies ventriculaire gauche diastolique que systolique, avec une amélioration des temps de contraction et de relaxation isovolumiques, de la torsion et de la détorsion ainsi que du remplissage du ventricule gauche. En l’absence d’hypertrophie ventriculaire gauche, la réduction de la fréquence cardiaque à des valeurs inférieures à 60 batt/min s’accompagnait d’un effet délétère fréquence-dépendant, à l’origine d’une altération isolée de la fonction diastolique caractérisée par une diminution de la détorsion du ventricule gauche et une augmentation de la pression télédiastolique ventriculaire gauche. La caractérisation de la fonction ventriculaire gauche et l’étude du couplage contraction-relaxation par la mesure de la torsion et de la détorsion en cas de décompensation cardiaque restent à déterminer. / Chronic hypertension induces left ventricular (LV) hypertrophy, resulting in abnormalities in LV relaxation, passive stiffness and filling. The higher the heart rate, the more pronounced the LV diastolic dysfunction. Moreover, in the normal heart, there is a tight coupling between LV contraction and relaxation, implying that in case of preserved contraction-relaxation coupling during LV hypertrophy, there is no diastolic dysfunction without systolic dysfunction. Thus, the three main objectives of this thesis were to investigate 1) the LV function and contraction-relaxation coupling with LV twist and untwist, which represent LV myocardial deformation during systole and diastole, 2) the cellular mechanisms of the LV contraction-relaxation coupling and 3) the effects effects of heart rate reduction on LV twist and untwist in the context of chronic hypertension and LV hypertrophy. All experiments were conducted in a pig model of chronic hypertension and LV hypertrophy induced by four weeks of continuous angiotensin II infusion. Chronic angiotensin II infusion decreased LV twist and untwist but also delayed LV untwist in the cardiac cycle, whereas the LV ejection fraction was preserved. The contraction-relaxation coupling was preserved as illustrated by the strong relationship between LV twist and untwist. The contraction-relaxation coupling was also preserved at the level of cardiomyocytes. This implies that LV hypertrophy is associated with concomitant LV diastolic and systolic dysfunction despite preserved LV ejection fraction. Thus, LV diastolic dysfunction is always accompanied by LV systolic dysfunction, i.e., the discovery of LV diastolic dysfunction with preserved ejection fraction might imply the track of LV systolic dysfunction. At the cellular level, LV systolic and diastolic dysfunctions were associated to aberrant calcium handling with a remodelling of the type 2 ryanodine receptor calcium release channel (RyR2), i.e., PKA-hyperphosphorylation and depletion of calstabin 2 (FKBP12.6). RyR2 were leaky and hypersensitive to cytosolic calcium, during both the contraction and the relaxation phases. Since both LV systolic and diastolic dysfunctions were associated to leaky and hypersensitive RyR2 channels, it might suggest considering RyR2 as an integrator contributing to control contraction-relaxation coupling during chronic hypertension and LV hypertrophy. Finally, we investigated the effects of heart rate reduction induced by ivabradine, an If-channel blocker, which does not modify atrioventricular or LV conduction and is devoid of any intrinsic negative inotropic or lusitropic effects. In the context of chronic hypertension and LV hypertrophy, ivabradine improved both LV systolic and diastolic functions, as attested by the improvement in contraction and relaxation times, LV twist and untwist as well as LV filling. Heart-rate independent effects of ivabradine, i.e., pleiotropic effects, participate to its beneficial effect. However, the cellular mechanisms of these beneficial effects of ivabradine were not elucidated and require further investigations. In normal heart, when heart rate was reduced to a low level (approximately <60 beats/min) with ivabradine, LV twist was not affected but LV diastolic function was altered as suggested by decreased LV untwist parameters and increased LV end-diastolic pressure. Investigation of contraction-relaxation coupling during decompensation from stable LV hypertrophy remains a goal to achieve.

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Internal combustion engines are used in many applications. The same engine type may have different components mounted to it depending upon its use. These engine mounted components need to be designed against fatigue in order to withstand the engine vibrations. Measured engine vibrations are commonly used as input data for fatigue estimation. The focus in this thesis is set on heavy-duty diesel engines, typically used in trucks, buses and industrial applications. All of the appended papers use engine vibration measurements to evaluate the proposed methods. In Paper A, the engine block motion is described with a seven degree of freedom kinematic model. These degrees of freedom consist of six rigid body modes and one assumed twisting degree of freedom. With this description, measured engine block vibrations can be used to accurately predict the vibration in positions that have not been measured. Relating the measured vibrations of an engine mounted component with the projected motion of the engine block at that same position, makes it possible to identify local dynamic phenomena. In Paper B, the kinematic model of Paper A is extended with three assumed bending deformation mode shapes. For the current engine type, all of the assumed deformation modes are ranked within the 10-300 Hz frequency range. The deformation mode of highest importance is the engine block twist. Including bending deformation increases the accuracy of the engine block vibration description but it also increases the demands on instrumentation. In Paper C, the possibility to modify measured engine vibration signals, for addition or removal of engine mounted components, is investigated. For this purpose, engine vibration measurements were performed with and without a 29 kg brake air compressor mounted to the engine. For the task of removing the effect that this engine mounted component has on the engine block, the two cases of knowing, and not knowing the vibration of the component are both considered. The proposed methodology successfully predicts the changes in engine vibration due to system modification. The proposed method can also be used to estimate the time response of a component's centre of gravity. In this study the component's dynamic properties are derived from measurements but they could also be produced using finite element analysis. This can be useful early in the design process to find critically stressed areas due to base excitation. / <p>QC 20171222</p>

Indiana University-Purdue University Indianapolis (IUPUI) / This paper is a study of the dynamics of a new family of maps from the complex plane to itself, which we call twisted tent maps. A twisted tent map is a complex generalization of a real tent map. The action of this map can be visualized as the complex scaling of the plane followed by folding the plane once. Most of the time, scaling by a complex number will \twist" the plane, hence the name. The "folding" both breaks analyticity (and even smoothness) and leads to interesting dynamics ranging from easily understood and highly geometric behavior to chaotic behavior and fractals.

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ABP1 (Auxin Binding Protein 1), qui peut se lier à l'auxine, est essentielle pour le développement des plantes. Il a été prouvé qu’elle a la capacité de se lier à l’auxine et de conduire le signal auxine dans les cellules. ABP1 est supposé être localisée et avoir des fonctions à la surface extérieure de la membrane plasmique à travers une composante inconnue. Au cours ma thèse, nous avons essayé d’étudier l'interaction entre ABP1 et le candidat de la composante inconnue, CBP1 (chez le maïs), qui est une protéine à ancres GPI déjà identifiée comme ayant la capacité de liaison au peptide de synthèse C-terminale d’ABP1 en 2006. L'orthologue de CBP1 chez arabidopsis appartient à une famille de gènes contenant 19 membres, dont seulement trois d'entre eux ont été prédit comme était des protéines à ancres GPI. Nous avons fait les caractérisations fonctionnelles de ces trois membres. Les données suggèrent que les protéines SKS à ancres GPI sont impliquées dans l'orientation de la cellule, le développement des gamétophytes et de l'embryon. / ABP1 (Auxin Binding Protein1), who can bind auxin, is essential for the development of plants. It was proved to have the ability to bind auxin and transduce auxin signal into the cells. It is supposed to be localized and functions at the outer surface of plasma membrane through unknown component. In my thesis, we tried to invesitgate the interaction between ABP1 and the candidate of the unknown component, CBP1 (From maize), which is GPI-acnhored and already identified as the binding ability to synthesized C-terminus peptide of ABP1 in 2006. The orthologous of CBP1 in arabidopsis belongs to a gene family with 19 members, in which only three of them were prediceted to be GPI anchored. We did the functional characterisation of these three GPI-anchored members. Data suggested that GPI-anchored SKS were involved in cell orientation, gametophyte and embryo development.

Orientador: Daniel Mário Ugarte / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-17T20:15:26Z (GMT). No. of bitstreams: 1 Tizei_LuizHenriqueGalvao_D.pdf: 12237887 bytes, checksum: e97ac7041ecfd4c30088cf9b43d9849a (MD5) Previous issue date: 2011 / Resumo: O desenvolvimento de novos materias tem grande interesse devido à ocorrência de novos fenômenos e propriedades, as quais podem ser usadas em futuras aplicações tecnológicas. Em particular, nas últimas décadas, esforços imensos foram realizados buscando compreender nanomateriais e os efeitos da redução de tamanho e de dimensão. Entre os diferentes avanços alcançados, podemos citar o desenvolvimento significativo de nanofios semicondutores (estruturas quasi-unidimensionais) com dezenas ou centenas de nanometros de espessura e milhares de nanometros de comprimento. O método mais utilizado para o crescimento de nanofios é o método catalítico chamado VLS (Vapor-Líquido-Sólido), no qual uma nanopartícula metálica serve como sorvedouro preferencial de átomos de um vapor e, também, como posição para a formação de um sólido (nanofio). O VLS foi proposto por Wagner e Ellis nos anos 60. Em nossos trabalhos, nos concentramos no estudo de nanofios de semicondutores III-V crescidos em um reator de Epitaxia de Feixe Químico (CBE) catalisados por nanopartículas de Au. Mais especificamente, estudamos nanofios de InP, InAs, InGaP, InAsP e heteroestruturas InP/InAs/InP. Como a qualidade de interfaces e homogeneidade química do material crescido, influenciam diretamente as propriedades ópticas e elétricas de nanofios, nossa pesquisa nos levou a avaliar os limites da aplicação de diversas técnicas de microscopia eletrônica de transmissão aplicadas: TEM (Microscopia Eletrônica de Transmissão), STEM (Microscopia Eletrônica de Transmissão em Varredura), HRTEM (Microscopia Eletrônica de Transmissão de Alta Resolução), EDS (Espectroscopia de Raios-X Dispersados em Energia) e EELS (Espectroscopia de Perda de Energia de Elétrons). Como consequência, determinamos os limites de detecção de variações químicas e de medidas de larguras de interfaces das diferentes técnicas. Em particular, devido às limitações impostas pelo dano por radiação no material, propusemos o uso de deslocamentos químicos de plasmons (EELS) para a caracterização química de nanoestruturas de semicondutores III-V. Desenvolvemos uma metodologia para a análise de seções transversais de nanofios de InAsP. Os experimentos realizados indicam a diferença entre os semicondutores produzidos por crescimento axial (catalítico) e por radial (bidimensional). Além disso, a análise química detalhada de heteroestruturas InP/InAs/InP levou a detecção de concentrações inesperados de As no segmento final de InP. Interpretamos esta observação como uma indicação de que As difunde através da nanopartícula catalisadora durante o crescimento, demonstrando uma rota de incorporação de elementos do grupo V em nanofios crescidos pelo método VLS. Finalmente, estudamos os efeitos de defeitos estruturais extendidos, como discordâncias na morfologia e distorções estruturais de nanofios. Neste sentido, observamos a torção de Eshelby em nanofios de InP contendo discordâncias em parafuso únicas. Nossos resultados mostram que as taxas de torção medida são muito maiores (até 100%) do que o previsto pela teoria elástica macroscópica. Isto mostra as mudanças significativas nas propriedades mecânicas e estruturais em nanoestruturas e ilustra o papel importante de estudos detalhados de microscopia eletrônica para a análise de deformações em nanoestruturas / Abstract: The development of new materials has great interest due to the possibility of finding new phenomena and properties, which can be used in technological applications. In particular, in the last decades, huge efforts have been made in order to understand nanomaterials and, the effects of size and dimensionality reduction. Among different advances, it is worth noting the significant development of semiconductor nanowires (quasi-one dimensional structures) with tens or hundreds of nanometers in diameter and thousands of nanometers in length. The catalytic method VLS (Vapor-Liquid-Solid) is the most used approach for nanowire preparation, in which a metal nanoparticle serves as a preferential sink for atoms from a vapor and, also, as the position for the solid nucleation; this method was proposed by Wagner and Ellis in the 60s. In our work, we have focused on the study of III-V semiconductor nanowires grown by Chemical Beam Epitaxy (CBE) catalyzed by Au nanoparticles. Specifically, we have studied different III-V nanowires (InP, InAs, InGaP and InAsP), as ell as, some heterostructured wires (InP/InAs/InP). As the quality of interfaces and the chemical homogeneity of materials directly influence the optical and electrical properties of nanowires, our research have led us to assess the limit of applicability of several characterization techniques based on transmission electron microscopy: TEM (Transmission Electron Microscopy), STEM (Scanning Transmission Electron Microscopy), HRTEM (High Resolution Transmission Electron Microscopy), EDS (Energy Dispersed X-Ray Spectroscopy) and EELS (Electron Energy Loss Spectroscopy). As a consequence, we have determined the detection limit for the measurement of chemical composition variations and interface widths. In particular, due to the limitations imposed by radiation damage on III-V nanowires, we have proposed the use of Plasmon chemical shifts (EELS) to the chemical characterization of III-V nanostructures. We have analyzed the cross sections of InAsP nanowires and we have been able to reveal a difference between the semiconductors materials produced by the axial (catalytic) and radial (bidimensional) growth. Through the detailed chemical analysis of InP/InAs/InP heterostructures we have detected an unexpected concentration of As in the last InP segment of the heterostructure. We have interpreted this result as an indication that As diffuses through the catalytic nanoparticle during growth. This demonstrates an incorporation route for group V atoms in nanowires grown by VLS. Finally, we have studied the effects of extended structural defects, like dislocations, in the morphology and structural distortions of nanowires. In this sense, we have observed the Eshelby twist in InP nanowires containing a single screw dislocation. Our results show that measured twist rates are much larger (up to 100%) than the predictions from the elasticity theory. This shows the significant change of mechanical and structural properties in nanoscale and, illustrates the important role of a careful electron microscopy studies to analyze deformations in nanostructures / Doutorado / Física da Matéria Condensada / Doutor em Ciências

The diploma thesis aim to the design of equipment for ŠKODA JS a.s., which is part of a new inspection stand (N-SIO). This equipment is an inspection column that provides the possibility to inspect spent fuel assemblies at the operation of the Temelín nuclear power plant. This master thesis is also a summary of the whole design of the new inspection stand and a description of the individual inspection components and devices. One of the parts of the thesis is also a basic strength analysis and a drawing of the main assembly of inspection equipment.