The neural crest is a transient population of cells that forms a diverse range of derivatives in vertebrate embryos. Neural crest cells also migrate extensively throughout the embryo. The specification of a number of neural crest derivatives, including pigment cells and neurons and glia of the peripheral nervous system, is dependent on the transcription factor Sox10. In sox10 mutant zebrafish embryos, these neural crest derivatives fail to specify and subsequently the cell differentiation and migration fails leading to apoptosis. Sox10 mutant embryos also display an ear defect although the precise role of Sox10 in the ear is less well defined. Thus Sox10 controls an extensive gene regulatory network that drives the development of an important subset of neural crest derivatives and also functions during ear development. This gene regulatory network is currently poorly defined. The aim of this project was to identify genes that are both direct and indirect targets of Sox10 to further elucidate this gene regulatory network. To achieve this, a microarray approach was adopted. Initially, fluorescence activated cell sorting was employed to enrich for sox10 expressing cells from 24 hours post fertilization sox10:GFP transgenic embryos. The transcriptomes of WT and sox10 mutant cells were compared by microarray analysis to identify differentially regulated genes. A large number of target genes were identified by this method and by an unbiased in situ hybridization screen, 28 genes were validated. Of these, 23 genes were expressed in cells of the neural crest and down-regulated in sox10 mutant embryos. The majority of these genes were expressed in cells of the melanocyte and xanthophore lineages. 5 genes were expressed in the ear (otic vesicle) of which three otic vesicle genes were down-regulated while two otic vesicle genes were up-regulated in sox10 mutant embryos. Unfortunately due to time constraints, a study into the function of one of these target genes could not be completed. The series of validated genes identified during this project has opened new opportunities for research and has identified a number of highly expressed marker genes that will be useful in future studies. In addition, the microarray data presented will be a useful resource to aid the identification of further targets of Sox10.

This thesis presents a thorough investigation of the 2500th Anniversary Celebrations of the Founding of the Persian Empire by Cyrus the Great, held in Persepolis by the Shah of Iran in 1971. Since the time of the Celebrations they have been routinely demonised by historians and critics of the Pahlavi regime, who present them as evidence of the delusion and megalomania of an Oriental despot. The purpose of this thesis is to provide a more sober, balanced account of the events of 1971 and the preparations leading up to them, in order to understand more fully the aims and motivations of the Shah and his entourage in organising such a nationalist spectacle. It will argue that Iran benefitted greatly from the international exposure the event generated, politically, economically and culturally. Most accounts of the Celebrations have focussed primarily on the sumptuous Pahlavi hospitality, enjoyed by the world’s elite over the course of a few days in purpose-built accommodation at Persepolis, the former ceremonial capital of the Achaemenid dynasty. In contrast, the premise of this thesis is that the ceremonies at Persepolis and Pasargadae were just a small, albeit highly visible, part of the programme for the Celebrations. From the time the Celebrations were conceived in the late 1950s, exhibitions were organised, publications commissioned and buildings constructed. All were intended to contribute to the development and modernisation of Iran, and all were conceived with the Anniversary Celebrations in mind. Internationally too, the Celebrations aroused great interest. Hundreds of books and articles were published in conjunction with the event, and museum exhibitions, academic conferences and other special cultural events were organised around the world, giving an important boost to the field of Persian studies worldwide. Meanwhile, the Shah’s Iran was presented as a significant regional and global power. This thesis will contribute, therefore, to our understanding of the Celebrations, and more broadly the material effects of the politicisation of culture in the late Pahlavi period.

As the hereditary leader of the Safavid Sufi Order, Shah Ismail founded the Safavid dynasty in 1501. This study goes beyond Shah Ismail's historical legacy, however, to examine the pious and literary sources which have shaped a permanent place for him within the Alevi-Bektashi community, an Islamic sectarian minority in Turkey. / Although Shah Ismail has received extensive treatment in both historical chronicles and modern historiography, this dissertation locates the development of his cult in the legendary versions of his life story. In this respect, the Turkish "Minstrel Tale" (hikaye) is fundamental to the transformation of Shah Ismail's significance in the sectarian context. This dissertation also traces the development of his pious significance through both the "authentic" poetic works of Shah Ismail, as contained in his earliest collections of poetry, as well as the poetry attributed to Shah Ismail by the Alevi-Bektashi. It is further demonstrated how the poetry attributed to Shah Ismail is integrated into ritual structures. Through the examination of these disparate literary genres, this thesis accounts for Shah Ismail's legacy as it transformed and endured within a pious context beyond his lifetime and beyond his empire.

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Iran has come to the forefront of media and policy discussion in recent years due to the renewal of nuclear prospects within the complex nation. The media and much of the west has taken notice of the situation and made predictions and assertions often leading toward nuclear war between the United States and the Islamic Republic of Iran. However, the west often forgets our relationship with Iran when Muhammad Reza Shah, the last of the Shah's, was in power. From 1941 to 1979 the United States enjoyed peaceful relations with Iran; the two nations even reached a certain economic prosperity with each other. The Shah introduced reform that was pleasurable to the United States and in return, America traded and invested in Iran, including establishing a nuclear program in Iran and building a number of nuclear facilities. In 2005 when President Mahmoud Ahmadinejad, formally the mayor of Tehran, was elected the great eye of the United States turned once again to Iran, viewing it as a threat. This study explores the Shah's rule and Ahmadinejad's presidency; and perhaps more importantly, the American foreign policy that was established for both. A brief history of both Iranian leaders, their complexities; the external and internal factors that effected each individually and as a leader of the great nation will be followed by a comparison of both using the foreign policy of the United States as a medium for comparison. This thesis will perhaps expose an often ignored perspective on American Iranian foreign relations.

La première moitié du 19ème siècle, a constitué le point de départ de la mise en place de la modernisation d’Iran. Aucun domaine n’a pu échapper au défi lancé par la modernisation et la formation d’une nouvelle élite iranienne à travers l’envoi d’étudiants iraniens en Europe a contribué au projet de modernisation du pays. En considérant les jeunes iraniens instruits en Europe comme autant de figures emblématiques de mutation de la société iranienne dans le processus de la modernisation, ces derniers ont été considérés comme une élite moderne. Les évolutions sociopolitiques et économiques de la société iranienne, au début du 20ème siècle, mettent en lumière l’existence d’une dynamique de renouvellement et d’un changement élitaire. Les étudiants en tant qu’acteurs principaux du processus de modernisation de l’Iran constituent un nouveau courant de pensée, une nouvelle manière d’envisager la société par l’émergence de courants politiques et de nouvelles littératures. Dans ce registre la formation de la nouvelle élite en Iran à l’époque Pahlavi est passé par la formation d’enseignants instruits en Europe chargés de former la nouvelle élite nationale à l’intérieur du pays. Autrement dit ces étudiants ont été envoyés en Europe pour devenir formateurs, instituteurs et professeurs au sein des établissements d’enseignement iraniens à leur retour en Iran. En dressant le tableau de la vie quotidienne et les difficultés que ces étudiants ont rencontré, nous avons essayé de mettre en cause les idées reçues sur l’élite moderne et le rôle de l’élite et des intellectuels dans le projet de la modernisation ; sujet resté pendant longtemps entre mythe et réalité historique. / The first half of the 19th century was the starting point of the implementation of iranian modernization. No area has escaped the challenge posed by modernization and the formation of a new elite through the formation of Iranian students in Europe which has contributed to the modernization of Iran. Considering Iran's educated youth in Europe like so many emblematic figures of Iranian society’s transformation in the process of modernization, they have been regarded as a modern elite. The socio-political and economic developments of the Iranian society in the beginning of 20th century highlight the existence of a dynamic renewal and change of elite status. Students as major actors in the process of Iran’s modernization form a new school of thought, a new way of considering the society by the emergence of new political trend and literatures. In this context the formation of new elite in Iran in the Pahlavi era has gone through the training of teachers educated in Europe responsible for training the new national elite within the country. These students were sent to Europe to become at their return to Iran, trainers, teachers and professors in Iranian institutions. In drawing the picture of daily life and the difficulties that these students met, we tried to blame received ideas on the modern elite and its role in the project of modernization; a subject remained for a long time between myth and historical reality.

On étudie dans cette thèse la régularité des cônes et d'ensembles de dimension 3 dans l'espace Euclidien de dimension 4.Dans la première partie, on étudie d'abord la régularité Bi-Hölderienne des cônes minimaux de dimension 3 dans l'espace Euclidien de dimension 4. Ceci nous permet ensuite de montrer qu'il existe un difféomorphisme locale entre un cône minimal de dimension 3 dans l'espace Euclidien de dimension 4 et un cône minimal de dimension 3, de type P, Y ou T, loin d'origine. La méthode est la même que pour les ensembles minimaux de dimension 2. On construit des compétiteurs et on se ramène aux situations connues des ensembles minimaux de dimension 2 dans l'espace Euclidien de dimension 3.Dans la deuxième partie, on utilise le résultat de la première partie pour donner quelques résultats de régularité Bi-Hölderienne pour les ensembles minimaux de dimension 3 dans l'espace Euclidien de dimension 4. On s'intéresse aussi aux ensembles minimaux de Mumford-Shah et on obtient un résultat de l'existence d'un point de type T. / In this thesis we study the problems of regularity of three-dimensional minimal cones and sets in l'espace Euclidien de dimension 4In the first part we study the Hölder regularity for minimal cones of dimension 3 in l'espace Euclidien de dimension 4. Then we use this for showing that there exists a local diffeomorphic mapping between a minimal cone of dimension 3 and a minimal cone of dimension 3 of type P, Y or T, away from the origin. The techniques used here are the same as the ones for the regularity of two-dimensional minimal sets. We construct some competitors to reduce to the known situation of two-dimensional minimal sets in l'espace Euclidien de dimension 3.In the second part, we use the first part to give somme results of the Hölder regularity for three-dimensional minimal sets in l'espace Euclidien de dimension 4. We interested also in Mumford-Shah minimal sets and we get a result of the existence of a T-point.

Dans cette thèse, nous nous intéressons à la fois aux aspects théoriques et à la résolution numérique du problème de Mumford-Shah avec anisotropie pour la restauration et la segmentation d'image. Cette fonctionnelle possède en effet la particularité de reconstruire une image dégradée tout en extrayant l'ensemble des contours des régions d'intérêt au sein de l'image. Numériquement, on utilise l'approximation d'Ambrosio-Tortorelli pour approcher un minimiseur de la fonctionnelle de Mumford-Shah. Elle Gamma-converge vers cette dernière et permet elle aussi d'extraire les contours. Les implémentations avec des schémas aux différences finies ou aux éléments finis sont toutefois peu adaptées pour l'optimisation de la fonctionnelle d'Ambrosio-Tortorelli. On présente ainsi deux nouvelles formulations discrètes de la fonctionnelle d'Ambrosio-Tortorelli à l'aide des opérateurs et du formalisme du calcul discret. Ces approches sont utilisées pour la restauration d'images ainsi que pour le lissage du champ de normales et la détection de saillances des surfaces digitales de l'espace. Nous étudions aussi un second problème d'optimisation de forme similaire avec conditions aux bords de Robin. Nous démontrons dans un premier temps l'existence et la régularité partielle des solutions, et dans un second temps deux approximations par Gamma-convergence pour la résolution numérique du problème. L'analyse numérique montre une nouvelle fois les difficultés rencontrées pour la minimisation d'approximations par Gamma-convergence. / In this work, we study both theoretical and numerical aspects of an anisotropic Mumford-Shah problem for image restoration and segmentation. The Mumford-Shah functional allows to both reconstruct a degraded image and extract the contours of the region of interest. Numerically, we use the Amborsio-Tortorelli approximation to approach a minimizer of the Mumford-Shah functional. It Gamma-converges to the Mumford-Shah functional and allows also to extract the contours. However, the minimization of the Ambrosio-Tortorelli functional using standard discretization schemes such as finite differences or finite elements leads to difficulties. We thus present two new discrete formulations of the Ambrosio-Tortorelli functional using the framework of discrete calculus. We use these approaches for image restoration and for the reconstruction of normal vector field and feature extraction on digital data. We finally study another similar shape optimization problem with Robin boundary conditions. We first prove existence and partial regularity of solutions and then construct and demonstrate the Gamma-convergence of two approximations. Numerical analysis shows once again the difficulties dealing with Gamma-convergent approximations.

La modélisation de processus complexes peut impliquer un grand nombre de variables ayant entre elles une structure de corrélation compliquée. Par exemple, les phénomènes spatiaux possèdent souvent une forte régularité spatiale, se traduisant par une corrélation entre variables d’autant plus forte que les régions correspondantes sont proches. Le formalisme des graphes pondérés permet de capturer de manière compacte ces relations entre variables, autorisant la formalisation mathématique de nombreux problèmes d’analyse de données spatiales. La première partie du manuscrit se concentre sur la résolution efficace de problèmes de régularisation spatiale, mettant en jeu des pénalités telle que la variation totale ou la longueur totale des contours. Nous présentons une stratégie de préconditionnement pour l’algorithme generalized forward-backward, spécifiquement adaptée à la résolution de problèmes structurés par des graphes pondérés présentant une grande variabilité de configurations et de poids. Nous présentons ensuite un nouvel algorithme appelé cut pursuit, qui exploite les relations entre les algorithmes de flots et la variation totale au travers d’une stratégie de working set. Ces algorithmes présentent des performances supérieures à l’état de l’art pour des tâches d’agrégations de données geostatistiques. La seconde partie de ce document se concentre sur le développement d’un nouveau modèle qui étend les chaînes de Markov à temps continu au cas des graphes pondérés non orientés généraux. Ce modèle autorise la prise en compte plus fine des interactions entre noeuds voisins pour la prédiction structurée, comme illustré pour la classification supervisée de tissus urbains. / Modeling complex processes often involve a high number of variables with anintricate correlation structure. For example, many spatially-localized processes display spatial regularity, as variables corresponding to neighboring regions are more correlated than distant ones. The formalism of weighted graphs allows us to capture relationships between interacting variables in a compact manner, permitting the mathematical formulation of many spatial analysis tasks. The first part of this manuscript focuses on optimization problems with graph-structure dregularizers, such as the total variation or the total boundary size. We first present the convex formulation and its resolution with proximal splitting algorithms. We introduce a new preconditioning scheme for the existing generalized forward-backward proximal splitting algorithm, specifically designed for graphs with high variability in neighbourhood configurations and edge weights. We then introduce a new algorithm, cut pursuit, which used the links between graph cuts and total variation in a working set scheme. We also present a variation of this algorithm which solved the problem regularized by the non convex total boundary length penalty. We show that our proposed approaches reach or outperform state-of-the-art for geostatistical aggregation as well as image recovery problems. The second part focuses on the development of a new model, expanding continuous-time Markov chain models to general undirected weighted graphs. This allows us to take into account the interactions between neighbouring nodes in structured classification, as demonstrated for a supervised land-use classification task from cadastral data.