L'inversion des marges passives apparaît comme le premier stade vers l'initiation de nouvelles zones de subduction. Cette étape cruciale dans la tectonique des plaques soulève néanmoins encore de nombreuses questions. L'étude des marges actuellement réactivées en compression apparaît ainsi comme essentielle pour mieux comprendre ce processus. Ces marges sont peu nombreuses, situées dans des contextes géodynamiques variés, et les facteurs déterminant leur évolution mal contraints. Située au nord de l'Afrique, la marge algérienne fait partie de ces rares exemples potentiels à travers le monde. L'évolution de cette marge formée au Miocène en contexte d'arrière-arc s'intègre dans le puzzle complexe de l'histoire de la Méditerranée occidentale. Elle est depuis quelques millions d'années réactivée en compression dans le cadre de la convergence lente entre les plaques européenne et africaine, générant un potentiel sismogène fort au nord de l'Algérie. La relative jeunesse du bassin algérien, la charge sédimentaire, les forces aux limites compressives, constituent des conditions favorables à la formation d'une future subduction. A la suite des travaux menés depuis une dizaine d'années, les principales lacunes de connaissances identifiées portent sur (1) la structuration profonde du bassin algérien et de sa marge sud (type de marge, nature du socle,dimension et nature de la transition océan-continent, style et distribution de la déformation compressive), et (2) l'histoire de l'évolution cinématique et géodynamique du bassin, ce qui limite à l'heure actuelle une analyse approfondie des modalités d'inversion de cette marge. L'étude menée se focalise sur la marge centre-algérienne, dans le secteur de Tipaza (à l'ouest d'Alger), un endroit clé pour la compréhension des mécanismes d'ouverture du bassin algérien. Le traitement et l'analyse de nouvelles données de sismique profonde grand-angle et multitraces acquises dans le cadre du projet franco-algérien SPIRAL (Sismique Profonde et Investigations Régionales en Algérie, 2009) ont notamment permis de déterminer la structure crustale du bassin algérien et de sa marge sud, ainsi que la structuration pseudo-3D d'une structure spécifique au secteur d'étude constituée par le haut topographique sous-marin de Khayr-al-Din. L'analyse de la structure profonde de la marge indique un certain nombre de structures héritées de son évolution complexe : (1) une croûte de nature continentale de plus de 15 km d'épaisseur sur le haut de marge (banc de Khayr-al-Din), (2)une croûte fine de nature océanique de 5-6 km d'épaisseur dans le bassin incluant des vitesses légèrement élevées à sa base (7,2 km/s - 7,3 km/s), (3) des similitudes avec des marges formées dans des contextes de déformation transformante, (4) un approfondissement progressif de l'ensemble de la pile sédimentaire et l'épaississement des sédiments Plio-Quaternaire, depuis le bassin profond distal vers le pied de marge,coïncidant avec (5) une flexuration à grande longueur d'onde du socle. Les résultats obtenus apportent de nouvelles contraintes sur (1) la géométrie et la nature de la marge et du bassin, (2) l'évolution de la marge,suggérant une histoire multiphasée comprenant un stade de rifting et/ou d'accrétion océanique, suivi d'un épisode de déformation coulissante tardive liée à la migration du bloc Alboran vers l'ouest, et d'une reprise en compression distribuée du bassin profond au haut de la marge au Plio-Quaternaire; (3) les modalités de réactivation qui se traduisent par des chevauchements aveugles néoformés à pendages sud, notamment au pied du banc de Khayr-al-Din, suggérant un soulèvement du banc de 0,2 mm/an à 0,75 mm/an au Plio-Quaternaire et un début d'écaillage crustal. / The inversion of passive margins appears to be one of the first steps towards the initiation of new subduction zones. This crucial step in plate tectonics nevertheless still raises many questions. The study of margins currently reactivated by compressional tectonics is thus essential to better understand this process. These margins are uncommon, located in different geodynamic settings, and the factors determining their evolution are poorly constrained. The Algerian margin, located in North Africa, is one of handful of modern examples worldwide. The evolution of this margin, rifted during the Miocene, in a back-arc setting, is part ofthe complex puzzle of the western Mediterranean. Since a few million years, the margin has suffered inversion and compression in the framework of slow on going convergence between the European and African plates. This convergence generates moderate to strong earthquakes in North Algeria. The relatively young age of the Algerian basin, the large sediment load, and the compressive forces, constitute favorable conditions to the formation of a future subduction zone. Studies from the past ten years indicate, that themain unresolved questions are related to (1) the deep structure of the Algerian basin and its southern margin (the type of margin, the nature of the basement, the dimension and nature of the ocean-continent transition, the style and the distribution of the compressional deformation), and (2) the history of the kinematic and geodynamic evolution of the basin. All of these unknowns have prevented a complete and thorough analysis of modalities of the Algerian margin inversion. This study focuses on the Central Algerian margin, in the area of Tipaza (West of Algiers), a key region to understand the mechanism of the opening of the Algerian basin. Processing and analysis of a deep wide-angle and multichannel seismic new data set acquired in the context of the French-Algerian project SPIRAL (Sismique profonde et Investigation Régionales en Algérie, 2009)have enabled us to determine the crustal structure of the Algerian basin and its southern continental margin,as well as the pseudo-3D structure of a specific feature in the study area: the submarine topographic highformed by the Khayr-al-Din bank. The analysis of the deep structure of the margin reveals features inherited from its complex evolution: (1) a crust of continental nature of more than 15 km thick at the upper margin(Khayr-al-Din Bank), (2) a thin crust of oceanic nature, 5-6 thick in the deep basin, including slightly high velocities at its base (7.2 km/s - 7.3 km/s), (3) similarities with margins formed in context of transform deformation, (4) a progressive deepening of the whole sedimentary cover and the thickening of the Plio-Quaternary sediments, from the distal deep basin towards the margin foot, coeval with (5) a long wavelengthflexuration of the basement in the basin. Results from this study provide new constraints on (1) the geometryand nature of the margin and the basin, (2) the evolution of the margin, suggesting a multiphased history including a stage of rifting and/or oceanic spreading, a transcurrent episode due to the westward migration of the Alboran block, and a diffuse Plio-Quaternary compressional reactivation distributed from the deep basinto the upper margin; (3) the mechanisms of the reactivation marked by newly formed south-dipping blind-thrusts, especially at the foot of the Khayr-al-Din bank, and suggesting a Plio-Quaternary uplift of the bankof 0.2 mm/y to 0.75 mm/y and the early stages of imbricate thrusting of crustal scales.

Cette thèse consiste en une analyse de l’État sénégalais en actes et de ses processus de gouvernementalité tels que ceux-ci sont déployés en Casamance. Au travers de la lutte contre le paludisme, comme objet ethnographique, ce travail mène une analyse de la fabrique de la légitimité étatique dans une région où celle-ci est remise en question. Il s'agit, au travers des actes d’État, d'interroger les relations entre les appareils d’État (idéologiques et coercitifs), les partenaires de l’État et les communautés. Les ajustements structuraux des années 1980, la décentralisation qui en découle et la mise en place des appareils communautaires ont participé, auprès de la population, de la dégradation de l'image d'un État fort. Cette dégradation, en contexte casamançais, fut exacerbée par une crise de la légitimité étatique trouvant son origine dans un conflit social. Celui-ci est survenu suite au sentiment éprouvé par les populations d'un État vécu comme pilleur et incapable d'assurer le bien-être de ses administrés. Aujourd'hui, alors que la Casamance reste en proie à un conflit de basse-intensité, l'imaginaire d'un État ayant « abandonné » la région subsiste. Comment, dès lors, l’État fabrique sa légitimité alors qu'il n'apparaît majoritairement aux yeux des Casamançais qu'au travers de ses prérogatives violentes ? Alors que ses appareils coercitifs sont très visibles (contrôles militaires et policiers réguliers), comment apparaît-il sous ses formes bienveillantes lui permettant de légitimer sa présence ? Ainsi, par une analyse du déploiement du biopouvoir, au travers de la mise en place des politiques de lutte contre le paludisme, cette thèse interroge la fabrique de l’État en Casamance. Cette recherche constitue ainsi une anthropologie politique. / This thesis consists in a Senegalese State analysis in its works and its governmentality process deployed in Casamance. Through the combat against malaria as an ethnographic field of investigation, this work analyses the fabrication of the State legitimacy in a region where it is challenged. It's about the investigation into the relations between the political apparatus (ideological and coercive), the government collaborators and communities through the State works. The structural adjustment of the 80's which has led to the decentralization and the community apparatus setting up, contributed to deteriorate the State's image for the people. A crisis of the legitimacy of the State rooted in a social conflict, exacerbated this deterioration in a Casamance context. This conflict appeared because the people felt that the State was a looter and was unable to provide for their well-being. Today, the imaginary of a State which has "given up" the region still goes on when Casamance still knows a weakened conflict. Consequently, how does the State build its legitimacy when it mainly reveals itself to the Casamances through its violent prerogatives? How does it appear by its benevolent forms allowing to legitimate its presence when its coercive apparatus are so obvious (military control and legitimate police)? Thus, this thesis questions, through an analysis of the deployment of the bio-powerand through the setting up of the policies to combat malaria, the fabrication of the State in Casamance. This research constitutes in this way a political anthropology.

Orientador: Dilson Amancio Alves / Banca: Percival Bueno de Araujo / Banca: Carlos Roberto Minussi / Banca: Geraldo Roberto Martins da Costa / Banca: Luiz Carlos Pereira da Silva / Resumo: Este trabalho apresenta dois métodos para a análise estática de contingências em Sistemas Elétricos de Potência utilizando o Método da Continuação. No primeiro método a margem de carregamento pós-contingência é obtida a partir do ponto de máximo carregamento do caso base. A magnitude de tensão de uma barra qualquer é usada como parâmetro na etapa de parametrização do fluxo de carga continuado. O ramo selecionado para avaliação da contingência é parametrizado por um fator de escalonamento que possibilita a remoção gradual do ramo e assegura a convergência nos casos em que o método diverge para a retirada total da linha de transmissão. Em geral, para a maioria das contingências analisadas são necessárias poucas iterações para a determinação do ponto de máximo carregamento pós-contingência. Mostra-se que o método pode ser usado como uma técnica alternativa para a averiguação e até mesmo para a obtenção da lista de contingências críticas fornecida pela função de análise de segurança de sistemas elétricos. No outro método, o qual obtém o ponto de máximo carregamento de pós-contingência a partir do caso base, as variáveis ângulo de fase e magnitude de tensão de uma barra k qualquer, e a perda total de potência ativa, são propostas como parâmetros para a etapa de parametrização do fluxo de carga continuado utilizado na averiguação da lista de contingências críticas fornecida pela função de análise de segurança de sistemas elétricos. Nos casos em que há divergência do fluxo de carga, o método proposto possibilita confirmar se esta ocorre devido à deficiência numérica do método em si ou a inexistência de um ponto de operação factível de pós-contingência. O uso da perda total de potência ativa como parâmetro traz como vantagem a possibilidade da determinação de pontos além do ponto de singularidade sem a necessidade...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work presents two methods for static contingency analysis of electric power systems by using Continuation Methods. In the first the post-contingency loading margin is obtained from the base case maximum loading point. The voltage magnitude of any bus can be used as a parameter in the parameterization step of the proposed continuation power flow. The branch selected for contingency evaluation is parameterized by a scaling factor which allows its the gradual removal and assures the continuation power flow convergence for the cases where the method would diverge for the complete transmission line removal. In general, for most of the analyzed contingencies little iterations are necessary for the determination of the post-contingency maximum loading point. It is shown that the method can be used as an alternative technique to verify and even to obtain the list of critical contingencies supplied by the electric power systems security analysis function. In the other method, which obtains the maximum loading point from the base case, new parameters, namely the voltage magnitudes, phase angles and the total power losses, for evaluating the effects of branch outages. The approach can be used as a verification tool after a list of critical contingencies had been ranked according to their severities by the contingency selection functions. It is then possible to find whether the non-convergence of a power flow is due to a numerical problem or to an infeasible operating situation. The mains advantage of using the total real power losses as a parameter is that it is not necessary to change parameters during the solutions tracing until beyond the simple limit point, where the original Jacobian is singular. The proposed methods facilitate the development and the implementation of continuation methods for contingencies analysis / Doutor

A need has been established in industry and academic publications to link an engine's maintenance costs throughout its operational life to its design as well as its operations and operating conditions. The established correlations between engine operation, design and maintenance costs highlight the value of establishing a satisfactory measure of the relative damage due to different operating conditions (operational severity). The methodology developed in this research enables the exploration of the causal, physics-based relationships underlying the statistical correlations in the public domain and identifies areas for further investigation. This thesis describes a physics-based approach to exploring the interactions, for commercial aircraft, of engine design, operation and through life maintenance costs. Applying the "virtual-workshop" workscoping concept to model engine maintenance throughout the operating life captures the maintenance requirements at each shop visit and the impact of a given shop visit on the timing and requirements for subsequent visits. Comparisons can thus be made between the cost implications of alternative operating regimes, flight profiles and maintenance strategies, taking into account engine design, age, operation and severity. The workscoping model developed operates within a physics-based methodology developed collaboratively within the research group which encompasses engine performance, lifing and operational severity modelling. The tool-set of coupled models used in this research additionally includes the workscoping maintenance cost model developed and implements a simplified 3D turbine blade geometry, new lifing models and an additional lifing mechanism (Thermo-mechanical fatigue (TMF)). Case studies presented model the effects of different outside air temperatures, reduced thrust operations (derate), flight durations and maintenance decisions. The use of operational severity and exhaust gas temperature margin deterioration as physics based cost drivers, while commonly accepted, limit the comparability of the results to other engine-aircraft pairs as the definition of operational severity, its derivation and application vary widely. The use of a single operation severity per mission based on high pressure turbine blade life does not permit the maintenance to vary with the prevalent lifing mechanism type (cyclic/steady state).

Par l’écriture, Toni Morrison cherche à rendre leurs voix à ceux qui ont été interdits de mots. Auteure engagée, elle veut redonner à la minorité noire sa place centrale dans l’Histoire des États-Unis. Elle propose ainsi une ré-écriture de l’Histoire au travers de sa trilogie historique, composée de Beloved, Jazz et Paradise, ré-écriture déjà en germe dans son second roman, Sula. À travers l’étude de ces quatre romans, cette thèse se propose de mettre au jour la généalogie de l’indicible dans l’œuvre de Toni Morrison, mais aussi d’analyser le lien dynamique entre minoration et écriture chez cette auteure qui revendique son statut de romancière noire américaine. Les femmes occupent une place centrale dans notre corpus car, à la minoration raciale qui relègue déjà les Africains-Américains en marge de la société américaine, s’ajoute pour les femmes noires la minoration sexuelle qui les réduit à un corps-objet. Mais chez Toni Morrison, cette double minoration, et la fragmentation qu’elle entraîne, deviennent des lignes de fuite, au sens deleuzien du terme, qui (dé-)structurent son écriture. La minoration ne s’entend alors plus comme soustraction, mais comme création. Toni Morrison trace ainsi dans ses textes des lignes de fuite créatrices qui s’échappent du cadre de la page vers un en-dehors du langage où se dit le désir de résister et de survivre du mineur. / Toni Morrison’s writing aims at giving their voices back to those who were deprived of words. As a committed writer, Toni Morrison wants to highlight the central role of the black minority in the History of the United States. She then offers a new version of History as she rewrites it through her historical trilogy comprising her novels Beloved, Jazz and Paradise, to which can be added her second novel, Sula, where the seeds of the rewriting of History can already be found. Through the analysis of these four novels, the objective of this doctoral thesis is to excavate the genealogy of the unspeakable in Toni Morrison’s work, and to analyze the dynamic relationship between minoration and writing for an author who’s « insisted – insisted ! – upon being called a black woman novelist. » Women play a central part in the four novels we are studying because, to the racial minoration that already marginalizes African-Americans in the American society must be added for black women the sexual minoration which turns them into a mere body-object. But this double minoration, and the fragmentation it leads to, become in Toni Morrison’s work “lines of flight”, according to Gilles Deleuze’s terminology, which (de-)construct her writing. Minoration is therefore no longer to be understood as subtraction but as creation. Thus, Toni Morrison draws in her texts the lines of flight of creation which leak out of the page towards the outside of language where one can hear the desire for resistance and survival of the minor.

Online learning algorithms have several key advantages compared to their batch learning algorithm counterparts: they are generally more memory efficient, and computationally mor efficient; they are simpler to implement; and they are able to adapt to changes where the learning model is time varying. Online algorithms because of their simplicity are very appealing to practitioners. his thesis investigates several online learning algorithms and their application. The thesis has an underlying theme of the idea of combining several simple algorithms to give better performance. In this thesis we investigate: combining weights, combining hypothesis, and (sort of) hierarchical combining.¶ Firstly, we propose a new online variant of the Bayes point machine (BPM), called the online Bayes point machine (OBPM). We study the theoretical and empirical performance of the OBPm algorithm. We show that the empirical performance of the OBPM algorithm is comparable with other large margin classifier methods such as the approximately large margin algorithm (ALMA) and methods which maximise the margin explicitly, like the support vector machine (SVM). The OBPM algorithm when used with a parallel architecture offers potential computational savings compared to ALMA. We compare the test error performance of the OBPM algorithm with other online algorithms: the Perceptron, the voted-Perceptron, and Bagging. We demonstrate that the combinationof the voted-Perceptron algorithm and the OBPM algorithm, called voted-OBPM algorithm has better test error performance than the voted-Perceptron and Bagging algorithms. We investigate the use of various online voting methods against the problem of ranking, and the problem of collaborative filtering of instances. We look at the application of online Bagging and OBPM algorithms to the telecommunications problem of channel equalization. We show that both online methods were successful at reducing the effect on the test error of label flipping and additive noise.¶ Secondly, we introduce a new mixture of experts algorithm, the fixed-share hierarchy (FSH) algorithm. The FSH algorithm is able to track the mixture of experts when the switching rate between the best experts may not be constant. We study the theoretical aspects of the FSH and the practical application of it to adaptive equalization. Using simulations we show that the FSH algorithm is able to track the best expert, or mixture of experts, in both the case where the switching rate is constant and the case where the switching rate is time varying.

在《時空邊緣的女人》中，作者藉著揭露一位墨裔美籍女性穿梭時空的故事，來探討弱勢族群在美國資本主義社會中被邊緣化的困境，並批判美國社會中以中產階級白人男性觀點為主流價值標準而形成對「異己」團體及文化的壓迫、歧視與剝削。作者運用科幻小說技巧中的異想（fantasy），連結現在與未來，對比１９７０年代的美國現實社會和西元２１０７年的烏托邦世界，揉合女性主義及後現代主義精神，以檢驗並批判當代美國社會之窳陋，並試圖勾勒一個多元價值並存、兩性尊重平等、自然與科技平衡的願景。 此篇論文共分四章。第一章略述小說文本的概要及其寫作背景，並討論分析此一文本所應用之理論和概念：後現代主義、女性主義、烏托邦文學和科幻小說，及此四者所交織出對於典律(canon)之質疑和批判的策略。第二章討論作者如何運用後現代批判形式之論述策略來表達其女性主義之關懷，形成邊陲與中心的對話。第三章的焦點集中於探討女主角穿梭時空下對比現實世界、未來烏托邦和反烏托邦世界所牽引出──語言、歷史、科學╱科技、生態、性╱別以及主體──一系列課題之批判思考。最後一章則回顧前述的理論如何與文本的內容及形式相結合，以挑戰現實世界及讀者心中牢固偏執的主流意識形態。 / Struggling with the social norms of gender and to be a 'visible' woman writer, Marge Piercy challenges and interrogates the canonical, patriarchal hegemony that dominates the culture. Her work, Woman on the Edge of Time, invites multiple alternatives by imagining beyond what is taken for granted. This thesis aims to explore how the heroine's time-travel undergoes a dialogic process between the past, present and future, which effects a feminist politics to examine the social norms and to anticipate a change toward an egalitarian world. This thesis is divided into four chapters. The first chapter offers an overview of both the text and context of this novel. Since I define this novel as a generic mixture of feminist utopian writing and postmodern science fiction, I first introduce theories of postmodernism, feminism, science fiction, and utopian writing, and their intersections. The exploration of theories here paves the way for the textual analysis in later discussion. In the second chapter, I discuss how the writer manipulates postmodern strategies to express her feminist concerns of destabilizing the canon and enabling a dialogic interaction between the margin and the center. The third chapter focuses on key debates within feminist discourse, which are revealed and symbolized through the heroine's telepathic experiences communicating between the dystopian present and the utopian future. The feminist thinking toward language, history, science/technology, ecology, gender/sexuality, and subjectivity is elaborated in this chapter. Finally, the concluding chapter reviews theories and issues concerning both postmodernist and feminist thinking highlighted through the heroine's time-travel/mind-travel, which is a dialogic process bringing up different voices and perspectives--a voyage of rethinking and reshaping.

We present robust explicit construction of 3D configuration spaces using controlled linear perturbation. The input is two planar parts: a fixed set and a moving set, where each set is bounded by circle segments. The configuration space is the three-dimensional space of Euclidean transformation (translations plus rotations) of the moving set relative to the fixed set. The goal of constructing the 3D configuration space is to determine the boundary representation of the free space where the intersection of the moving set and fixed set is empty. To construct the configuration space, we use the controlled linear perturbation algorithm. The controlled linear perturbation algorithm assigns function signs that are correct for a nearly minimal input perturbation. The output of the algorithm is a consistent set of function signs. This approach is algorithm-independent, and the overhead over traditional floating point methods is reasonable. If the fixed and moving sets are computer representations of physical objects, then computing the configuration space greatly aids in many computational geometry problems. The main focus of computing the configuration space is for the path planning problem. We must find if a path exists from the start to the goal, where the fixed set is the obstacle, and the moving set is the object trying to reach the goal.

Das Phänomen der Subduktion eines aktiven Spreizungszentrums an der Südspitze Südamerikas ist seit langem bekannt. Eine Vielzahl von geologischen Beobachtungen wurden mit diesem Phänomen in Verbindung gebracht, trotzdem ist der genaue Mechanismus der Beeinflussung des aktiven Kontinentalrandes weitgehend unbekannt. <br /> <br /> Die Zusammenhänge zwischen den Subduktionsprozessen und der Entwicklung der patagonischen Anden zwischen 47&#176;S und 48&#176;S stehen im Mittelpunkt der Untersuchungen. Um eine detaillierte zeitliche Auflösung der zugrunde liegenden Prozesse untersuchen zu können, wurde die Entwicklung der Vorlandsedimentation, die thermische Entwicklung und die Heraushebung der Oberkruste des andinen Orogens untersucht und diese in Bezug zur Subduktion des Chile-Rückens gesetzt. <br /> <br /> Im Bereich von 47&#176;30&prime;S wurden die synorogenen Vorlandsedimente der Santa Cruz Formation sedimentologisch untersucht. Diese fluviatilen Sedimente wurden in einem reliefarmen Vorlandgebiet durch häufige Rinnenverlagerung und dem Aufbau von Rinnenumlagerungsgürteln in Kombination mit assoziierten großräumigen Überflutungsablagerungen akkumuliert. Sie stehen in einem engen Zusammenhang mit der orogenen Entwicklung im andinen Liefergebiet. Dies spiegelt sich in dem nach oben gröber werdenden Zyklus der Santa Cruz Formation wider. Die magnetostratigraphischen Untersuchungen einer 270 m mächtigen Sequenz aus der Basis der Santa Cruz Formation, die mit 329 Einzelproben aus 96 Probenpunkten beprobt wurde, ergab 7 Umkehrungen der geomagnetischen Feldrichtung. Mit Hilfe der geomagnetischen Polaritätszeitskala (CANDE AND KENT, 1995) konnte der untersuchte Abschnitt der Santa Cruz Formation zwischen 16.2 und 18.5 Ma datiert werden. Als Träger der Sedimentations-Remanenz konnten überwiegend Pseudoeinbereichs-Magentitpartikel und untergeordnet Hämatitpartikel identifiziert werden. <br /> <br /> An drei Profilen der Santa Cruz Formation wurden aus Sandsteinlagen unterschiedlicher stratigraphischer Position detritische Apatite mit Hilfe der thermochronologischen Spaltspurmethode untersucht. Die thermisch nicht rückgesetzten, detritischen Apatite spiegeln das Auftreten unterschiedlicher Altersdomänen im Liefergebiet der Sedimente wider. In der Kombination mit den geochemischen Gesamtgesteinsuntersuchungen der Sedimente und den petrographischen Untersuchungen der Sandsteine, die ein überwiegend andesitisch-vulkanisch geprägtes Liefergebiet widerspiegeln, kann nachgewiesen werden, dass die Erosion im Liefergebiet um 16.5 Ma in tiefere, deformierte Krustensegmente einschneidet. Dies bedeutet, dass aufgrund der Denudation im andinen Orogen erste Sockelgesteinseinheiten in den Bereich der Abtragung gelangen und dass dieser Eintrag um 12 bis 10 Ma ein Volumen einnimmt, das zu signifikanten Änderungen der Gesamtgesteinsgeochemie der Vorlandsedimente führt. <br /> <br /> Die thermochronologische Untersuchung von Apatiten aus rezenten topographischen Höhenprofilen aus der Kernzone der patagonischen Anden im Bereich von 47&#176;30&prime;S zeigen den Beginn einer beschleunigten Heraushebung des Orogens um 7.5 Ma. Aus diesen Untersuchungen kann eine Denudationsrate im Zeitraum der letzen 7 bis 8 Ma von 600 bis 650 m/Ma abgeschätzt werden. Die Modellierung der Apatit-Spaltspurergebnisse zeigt eine signifikante Temperaturerhöhung im Zeitraum zwischen 12 und 8 Ma um 20 bis 30&#176;C für diesen Krustenbereich, die mit der Subduktion des aktiven Chile-Rückens in diesem Bereich der Anden in Verbindung gebracht wird. <br /> <br /> Aus den gewonnen Daten kann ein Modell für die Entwicklung der patagonischen Anden seit dem frühen Miozän abgeleitet werden. In diesem Modell wird die orogene Entwicklung in den patagonischen Anden auf eine erhöhte Konvergenzrate zwischen der Nazca Platte und der Südamerikanischen Platte zurückgeführt, die für die Heraushebung und Denudation der Anden sowie für die damit verbundene Entwicklung im Vorlandbereich verantwortlich ist. Diese orogene Entwicklung wird in einer späten Phase durch die nordwärts wandernde Subduktion des aktiven Spreizungszentrums des Chile Rückens überprägt und beeinflusst. Das auf der Integration von geologischen, chronologischen sowie thermochronologischen Daten beruhende Modell kann zahlreiche geologische und geophysikalische Beobachtungen in diesem Bereich der südlichen Anden konsistent erklären. / The phenomenon of active ridge subduction to the continental margin of southern South America has been well known for a long time. A diversity of geological observations are related to this phenomenon, however, the exact mechanism of the influence of ridge subduction to the active continental margin is unknown.<br /> <br /> The aim of the present investigations is to determine connections between the subduction processes and the development of the Patagonian Andes between 47&#176;S and 48&#176;S. In order to reach that objective, the development of the foreland basin settings, the uplift of the upper crust of the Andean Orogeny, and the relation with the subduction of the Chile Ridge were investigated to obtain a detailed temporal resolution of the basic geological processes.<br /> <br /> Within the area of 47&#176;30'S the style and sedimentological pattern of the synorogenic foreland deposits of the Santa Cruz Formation were investigated. These fluvial sediments were accumulated in a foreland basin of small scale topography by frequent progradational avulsions, which were accompanied by deposition of avulsion-belt sediments associated with thick overbank deposits. <br /> <br /> The upward-coarsening is best explained by progradation of fan deposits during an eastwards advancement of the deformation in the western Andes at that time. <br /> <br /> Magnetostratigraphic investigations of a total of 329 drill cores, which were collected at 96 sites, show seven major reversals in a thick stratigraphic section of 270 m from the base of the Santa Cruz Formation. A comparison with the geomagnetic polarity timescale of Cande and Kent (1995) gives a sedimentation age between 16.2 and 18.5 Ma for the investigated section of the Santa Cruz Formation. The investigation of rock-magnetism predominantly indicates magnetite and subordinated haematite as the dominant carrier of remanence. All results from hysteresis data determination cluster in the coarse pseudo-single (PSD) to multi-domain (MD) grain size range of the Day Diagram (DAY ET AL. 1977)<br /> <br /> Fission track analysis was applied to detrital apatite of sandstone samples at different stratigraphic positions within three sections of the Santa Cruz Formation. The fission track ages of the not reseted detrital apatite are assumed to be related to the age of the sediment provenance area. In combination with sandstone petrographic investigations, which indicate a dominant andesitic volcanic source for the sediment and geochemical whole rock investigations can be shown, that the erosion cuts into the basement of the source area at 16.5 Ma. This means, that due to the denudation in the Andean Orogen first deformed basement units arrive into the sedimentation cycle. In the range of 12 to 10 Ma this sediment input attained such a volume, that the whole-rock geochemistry of the sediments was changed .<br /> <br /> The thermochronological investigations of apatites from vertical profiles covering the largest elevation range of the central zone of the Patagonian Andes within the range of 47&#176;30'S show the beginning of an accelerated cooling and related uplift phase of the orogen at approximately 7.5 Ma. The calculated denudation rate in the period of the last 7 to 8 Ma ranges from 600 to 650 m/Ma. The modelling of apatite fission-track data shows a significant reheating in the range of 20 to 30&#176;C between 12 and 8 Ma for the upper crust. This is interpreted as an influence of the active Chile rise mid-oceanic spreading center on the overriding plate.<br /> <br /> The modelling of the apatite fission-track results shows a significant rise in temperature between 12 and 8 Ma around 20 to 30&#176;C for this crust area, which is associated with the subduction of the active Chile back in this area of the Andes. <br /> <br /> A model has been derived from the obtained data to explain the evolution of the Patagonian Andes since the early Miocene. In this model, orogeny is attributed to the increasing convergence rate between the Nazca plate and South America and its response due to uplift and denudation of the Patagonian Andes and the development of the adjacent foreland basin. In a late phase, orogeny is influenced and overprinted by the northward migration of the Chile ridge subduction. The model consistently explains many of the geological and geophysical observations.

The performance of analog integrated circuits is dependent on the technology. Digital circuits are scalable in nature, and the same circuit can be scaled from one technology to another with improved performance. But, in analog integrated circuits, the circuit components must be re-designed to maintain the desired performance across different technologies. Moreover, in the case of digital circuits, minimum feature-size (short channel length) devices can be used for better performance, but analog circuits are still being designed using channel lengths larger than the minimum feature sizes. The research in this thesis is aimed at understanding the impact of technology scaling and short channel length devices on the performance of analog integrated circuits. The operational amplifier (op amp) is chosen as an example circuit for investigation. The performance of the conventional op amps are studied across different technologies for short channel lengths, and techniques to develop technology-independent op amp architectures have been proposed. In this research, three op amp architectures have been developed whose performance is relatively independent of the technology and the channel length. They are made scalable, and the same op amp circuits are scaled from a 0.25 um CMOS onto a 0.18 um CMOS technology with the same components. They are designed to achieve large small-signal gain, constant unity gain-bandwidth frequency and constant phase margin. They are also designed with short channel length transistors. Current feedback, gm-boosted, CMOS source followers are also developed, and they are used in the buffered versions of these op amps.