Les progrès récents de la microfluidique, la biologie synthétique, la microscopie automatisée rendent aujourd'hui possible le contrôle externe de l'expression des gènes en temps réel. Parmi les défis que devra relever le domaine du contrôle externe et temps-réel de l'expression des gènes, se trouve la possibilité de contrôler des réseaux de régulation génique aux dynamiques complexes et multi-stables et le contrôle de multiples gènes en parallèle. Pour faire avancer le domaine dans cette direction nous avons étudié la contrôlabilité d'un réseau bistable composé de deux gènes, appelé genetic toggle switch, ou bascule génétique, autour de son point d'équilibre instable sur de longues périodes. Dans ce document, nous présentons la mise en place d'une plateforme de contrôle externe de l'expression des gènes en cellule unique, ainsi que le développement d'un châssis cellulaire bactérien et d'une librairie de circuits de bascules génétiques à contrôler. Nous utilisons la plateforme pour diriger et maintenir notre système génétique dans sa région d'instabilité avec des techniques de stabilisation à la fois en boucle ouverte et en boucle fermée. Nous démontrons non seulement que les plateformes de contrôle in silico peuvent être utilisées pour contrôler un système génétique dans un état hors-équilibre, nous démontrons aussi la possibilité de maintenir une population de cellules dans leur région d'instabilité à l'aide de stimulations périodiques en boucle ouverte. Ces résultats suggèrent l'émergence de régimes de stabilité différents dans des réseaux de régulation génique lorsqu'ils sont soumis à des environnements fluctuants, et peuvent fournir de nouvelles perspectives dans l'étude de la prise de décision cellulaire. Nous présentons aussi une nouvelle approche pour l'analyse d'images de microscopie qui exploite l'information cachée dans plusieurs plans focaux autour du spécimen au lieu d'utiliser seulement un seul plan focal. L'objectif de cette méthode est d'identifier automatiquement les différentes parties d'une image à l'aide de techniques d'apprentissage-machine inspirées de l'imagerie hyperspectrale. La méthode facilite la segmentation de l'image et peut être facilement adaptée à différents organismes / Recent progresses in microfluidics, synthetic biology and microscopy automation now make it possible to control gene expression externally and in real time. Among the challenges facing the field of external real-time control of gene expression is the control of intricate, multistable gene regulation networks as well as the control of several target genes at the same time. To advance the domain in this direction we studied the controllability of a simple bistable two-genes network, the so-called genetic toggle switch, in the vicinity of its unstable equilibrium point for extended periods of time. Throughout this document, we present the development of a custom control platform for external control of gene expression at the single-cell level as well as a bacterial cellular chassis and a library of toggle switch genetic circuits for us to control. We use the platform to drive and maintain our genetic system in its region of unstability with both closed-loop and open-loop strategies. Not only do we demonstrate that in silico control platforms can control genetic systems in out-of-equilibrium states, we also notably maintain a population of cells in their unstable area with open-loop periodic stimulations. These results suggest the possible emergence of different regimes of stability in gene regulation networks submitted to fluctuating environments, and can potential insights in the study of cellular decision making. We also introduce a new approach for microscopy image analysis which exploits information hidden in several focal planes around the specimen instead of using only a single-plane image. The objective of this method is to automatically label different parts of an image with machine learning techniques inspired by hyperspectral imaging. The method is then shown to facilitate segmentation and be easily adaptable to various different organisms

Le développement de la numérisation systématique des formes 3D (conservation du patrimoine national, commerce électronique, reverse engineering, intégration d’objets réels dans des environnements de réalité virtuelle) et le besoin toujours croissant de ces objets géométriques dans de nombreuses applications (conception assistée par ordinateur, calcul de simulations par éléments finis, système d’informations géographiques, loisirs numériques) a entrainé une augmentation vertigineuse du volume de données à traiter, avec l’émergence de nombreuses méthodes de compression de modèles 3D. Ce volume de données devient encore plus difficile à maitriser lorsque l’aspect temporel entre en jeu. Les maillages correspondent au modèle classiquement utilisé pour modéliser les formes numérisées et certaines approches de compression exploitent la propriété qu’une bonne estimation de la connectivité peut être déduite de l’échantillonnage, lorsque ce dernier s’avère suffisamment dense. La compression de la connectivité d’un maillage revient alors au codage de l’écart entre deux connectivités proches. Dans ce mémoire, nous nous intéressons au codage compact de cette différence pour des maillages surfaciques. Nos travaux sont fondés sur l’utilisation de la bascule d’arête (edge flip) et l’étude de ses propriétés. Nos contributions sont les suivantes. Etant donné deux triangulations connexes partageant le même nombre de sommets et un même genre topologique, nous proposons un algorithme direct et efficace pour générer une séquence de bascules d’arêtes permettant de passer d’un maillage `a un autre. Nous nous appuyons sur une correspondance entre les sommets des deux maillages, qui, si elle est non fournie, peut être choisie de manière totalement aléatoire / The development of scanning 3D shapes (national heritage conservation, ecommerce, reverse engineering, virtual reality environments) and the growing need for geometric objects in many applications (computer-aided design, simulations, geographic information systems, digital entertainment) have led to a dramatic increase in the volume of data to be processed, and the emergence of many methods of compression of 3D models. This volume of data becomes even more difficult to control when the temporal aspect comes in. Meshes correspond to the pattern typically used to model the scanned forms and some approaches exploit a property of compression that a good estimation of connectivity can be derived from sampling, when it appears sufficiently dense. Compressing the connectivity of a mesh is equivalent to coding the difference between two close connectivities. In this thesis, we focus on the compact coding of this difference for 2-dimensional meshes. Our work is based on the use and study of the properties of the edge flip. Our contributions are the following : - Given two connected triangulations that share the same number of vertices and the same topological genus, we propose a direct and efficient algorithm to generate a sequence of edge flips to change one mesh into the other. We rely on a correspondence between the vertices of the two meshes, which, if not provided, may be chosen randomly. The validity of the algorithm is based on the fact that we intend to work in a triangulation of a different class from those generally used. - We then generalize the edge flips to triangulations in which we identify each edge with a label. We show that a sequence of edge flips can be used to transpose two labels, under certain conditions. From this result, the edge flip can be generalized to meshes whose faces are not necessarily triangular, which allowed us to develop an algorithm for reducing sequences of edge flips. - Finally, we present a compact coding approach for a sequence of edge flips, and determine under what conditions it is better to use this compact transformation between two connectivities instead of coding them independently by a static algorithm

Made available in DSpace on 2017-07-10T19:24:48Z (GMT). No. of bitstreams: 1 Paulo Roberto Dulnik.pdf: 5194305 bytes, checksum: 354a67d6b39920693b0d770fe0b5dd6d (MD5) Previous issue date: 2006-06-13 / This paper objective was to develop a pluviograph with an optical sensor. The chosen modal to be developed was the bascule type for being versatile for the automatization process. To build the bascule, galvanized material was used. Te bascule, for precipitation measurement, has a sensibility of 0.3mm of liquid, that is, for every 0.3mm of rain precipitation there is collected water rejection and optical sensors, made of emission-receptor sets, send out pulses that are registered by an electronic counter and by a Personal Computer (PC). To build the receptor surface a 200 cm2-collecting ring was used and it is one of the most important parts of the instrument. This 200 cm2-receptor area is one of the most employed among pluviographs used in the country. The bascule system components were structured with bolted, removable parts without the use of soldering so it wouldn t cause deformity and to facilitate adjustments during building and testing. The electronic counter totals precipitation amount through the number of operations of the bascule system that are shown in a display. Through its parallel port, the computer uses a routine program and registers the amount of rain precipitation with the help of a transductional circuit. The computer software was developed in Visual Basic platform and named Monitor. On the computer screen, a table with the record of the 12 last operations performed by the bascule system is shown, and next to it, a three-indicator bar chart shows precipitation that occurred in the last minute, the last hour and in the last 24 hours (day). To validate the workability of the instrument, for comparative measurements, other two instruments were used: a Ville-de-Paris Conventional Pluviometer and a R. Fuess Siphon Pluviograph with readings taken at 9 AM. With these references, a considerable good performance was obtained, showing the record of the precipitation phenomenon with good regularity, which falls within this research expectation. Error relative to precipitation quantity pattern during measurements fell between 0mm and 1.9mm intervals. Error relative to the R. Fuess Siphon Pluviograph fell between 0mm and 2.1mm intervals. The least intense precipitation registered during this period(03/03/2006 04/14/2006) was 0.3mm, whereas the most intensive was 57mm. / Este trabalho estabeleceu como objetivo desenvolver um pluviógrafo com sensor ótico. O modelo escolhido para desenvolver foi o de caçambas (báscula), por ser bastante versátil para o processo de automatização. O material utilizado para construção da báscula foi chapa galvanizada. A báscula para medição da precipitação tem uma sensibilidade de 0,3 mm, isto é, a cada 0,3 mm de chuva acontece um descarte da água coletada e sensores óticos, formados por conjuntos emissor-receptor, emitem pulsos, contabilizados por um contador eletrônico e um microcomputador pessoal (PC). Para a construção da superfície receptora utilizou-se um anel de captação com área de 200 cm2, sendo uma das partes mais importantes do instrumento. Essa área de captação é uma das mais difundidas entre os pluviógrafos utilizados no Brasil. Os componentes do sistema basculante foram estruturados com peças totalmente desmontáveis, parafusadas e sem utilização de solda para não haver deformações e facilitar o ajuste durante a construção e testes. O contador eletrônico totaliza a quantidade precipitada pelo número de operações do sistema basculante, mostrado em um display. O computador, por meio de sua porta paralela, utiliza uma rotina de programa e registra no tempo a quantidade de chuva precipitada, com o auxílio de um circuito transdutor. O software foi desenvolvido em linguagem Visual Basic e denominado Monitor. Na tela do Monitor são mostrados uma tabela com o registro das últimas 12 operações realizadas pelo sistema basculante e, ao seu lado, um gráfico de barras com três indicações: a precipitação ocorrida no último minuto, na última hora e nas últimas 24 horas (dia). Para validar o funcionamento do instrumento foram utilizados, para medidas comparativas, outros dois instrumentos: como referência (padrão) um pluviômetro convencional tipo ville de Paris, além de um pluviógrafo de sifão (R. Fuess). Foram realizadas leituras a cada dia sempre às 9 horas. Com essas referências obteve-se um desempenho considerado bom, apresentando o registro do fenômeno da precipitação com boa regularidade, ficando dentro das expectativas deste trabalho de pesquisa. O erro relativamente ao padrão da quantidade de precipitação, durante as medições efetuadas, ficou compreendido entre o intervalo de 0 mm e 1,9 mm. O erro relativamente ao pluviógrafo de sifão (R. Fuess) ficou compreendido entre o intervalo de 0 mm e 2,1 mm. A precipitação menos intensa registrada nesse período( 03/03/2006 14/04/2006) foi de 0,3 mm e a mais intensa foi de 57 mm.

Made available in DSpace on 2017-05-12T14:48:12Z (GMT). No. of bitstreams: 1 Paulo Roberto Dulnik.pdf: 5194305 bytes, checksum: 354a67d6b39920693b0d770fe0b5dd6d (MD5) Previous issue date: 2006-06-13 / This paper objective was to develop a pluviograph with an optical sensor. The chosen modal to be developed was the bascule type for being versatile for the automatization process. To build the bascule, galvanized material was used. Te bascule, for precipitation measurement, has a sensibility of 0.3mm of liquid, that is, for every 0.3mm of rain precipitation there is collected water rejection and optical sensors, made of emission-receptor sets, send out pulses that are registered by an electronic counter and by a Personal Computer (PC). To build the receptor surface a 200 cm2-collecting ring was used and it is one of the most important parts of the instrument. This 200 cm2-receptor area is one of the most employed among pluviographs used in the country. The bascule system components were structured with bolted, removable parts without the use of soldering so it wouldn t cause deformity and to facilitate adjustments during building and testing. The electronic counter totals precipitation amount through the number of operations of the bascule system that are shown in a display. Through its parallel port, the computer uses a routine program and registers the amount of rain precipitation with the help of a transductional circuit. The computer software was developed in Visual Basic platform and named Monitor. On the computer screen, a table with the record of the 12 last operations performed by the bascule system is shown, and next to it, a three-indicator bar chart shows precipitation that occurred in the last minute, the last hour and in the last 24 hours (day). To validate the workability of the instrument, for comparative measurements, other two instruments were used: a Ville-de-Paris Conventional Pluviometer and a R. Fuess Siphon Pluviograph with readings taken at 9 AM. With these references, a considerable good performance was obtained, showing the record of the precipitation phenomenon with good regularity, which falls within this research expectation. Error relative to precipitation quantity pattern during measurements fell between 0mm and 1.9mm intervals. Error relative to the R. Fuess Siphon Pluviograph fell between 0mm and 2.1mm intervals. The least intense precipitation registered during this period(03/03/2006 04/14/2006) was 0.3mm, whereas the most intensive was 57mm. / Este trabalho estabeleceu como objetivo desenvolver um pluviógrafo com sensor ótico. O modelo escolhido para desenvolver foi o de caçambas (báscula), por ser bastante versátil para o processo de automatização. O material utilizado para construção da báscula foi chapa galvanizada. A báscula para medição da precipitação tem uma sensibilidade de 0,3 mm, isto é, a cada 0,3 mm de chuva acontece um descarte da água coletada e sensores óticos, formados por conjuntos emissor-receptor, emitem pulsos, contabilizados por um contador eletrônico e um microcomputador pessoal (PC). Para a construção da superfície receptora utilizou-se um anel de captação com área de 200 cm2, sendo uma das partes mais importantes do instrumento. Essa área de captação é uma das mais difundidas entre os pluviógrafos utilizados no Brasil. Os componentes do sistema basculante foram estruturados com peças totalmente desmontáveis, parafusadas e sem utilização de solda para não haver deformações e facilitar o ajuste durante a construção e testes. O contador eletrônico totaliza a quantidade precipitada pelo número de operações do sistema basculante, mostrado em um display. O computador, por meio de sua porta paralela, utiliza uma rotina de programa e registra no tempo a quantidade de chuva precipitada, com o auxílio de um circuito transdutor. O software foi desenvolvido em linguagem Visual Basic e denominado Monitor. Na tela do Monitor são mostrados uma tabela com o registro das últimas 12 operações realizadas pelo sistema basculante e, ao seu lado, um gráfico de barras com três indicações: a precipitação ocorrida no último minuto, na última hora e nas últimas 24 horas (dia). Para validar o funcionamento do instrumento foram utilizados, para medidas comparativas, outros dois instrumentos: como referência (padrão) um pluviômetro convencional tipo ville de Paris, além de um pluviógrafo de sifão (R. Fuess). Foram realizadas leituras a cada dia sempre às 9 horas. Com essas referências obteve-se um desempenho considerado bom, apresentando o registro do fenômeno da precipitação com boa regularidade, ficando dentro das expectativas deste trabalho de pesquisa. O erro relativamente ao padrão da quantidade de precipitação, durante as medições efetuadas, ficou compreendido entre o intervalo de 0 mm e 1,9 mm. O erro relativamente ao pluviógrafo de sifão (R. Fuess) ficou compreendido entre o intervalo de 0 mm e 2,1 mm. A precipitação menos intensa registrada nesse período( 03/03/2006 14/04/2006) foi de 0,3 mm e a mais intensa foi de 57 mm.

To assemble the fulcrum of bascule bridges, a trunnion is immersed into liquid nitrogen so that it can be shrunk fit into the hub. This is followed by immersing the resulting trunnion-hub assembly into liquid nitrogen so that it can be then shrunk fit into the girder. On one occasion in Florida, when the trunnion-hub assembly was put into liquid nitrogen, development of cracks on the hub was observed. Experimental and numerical studies conducted since 1998 at University of South Florida show that the cracking took place due to combination of high interference stresses in the trunnion-hub assembly, low fracture toughness of steel at cryogenic temperatures, and steep temperature gradients due to sudden cooling. In this study, we are studying the benefit of staged cooling to avoid cracking in the trunnion-hub assembly when it is cooled down for shrink fitting. We looked at three cooling processes - 1) Direct immersion into liquid nitrogen 2) Immersion into a refrigerated chamber, then liquid nitrogen 3) Immersion into a refrigerated chamber, then a dry-ice/alcohol bath, and finally liquid nitrogen. The geometry of the trunnion-hub assembly was approximated by a composite made of two infinitely long hollows cylinders. The transient problem of temperature distribution and the resulting stresses was solved using finite difference method. Using critical crack lengths and Von-Mises stress as failure criteria, the three cooling processes were compared. The study showed that the minimum critical crack length and stress ratio is increased by as much as 200% when cooling first in refrigerated air followed by liquid nitrogen. However, there is little benefit from adding dry-ice/alcohol as an intermediate step in the cooling process.

Avec l'explosion du marché des applications portables et le paradigme de l'Internet des objets, la demande pour les circuits à très haute efficacité énergétique ne cesse de croître. Afin de repousser les limites de la loi de Moore, une nouvelle technologie est apparue très récemment dans les procédés industriels afin de remplacer la technologie en substrat massif ; elle est nommée fully-depleted silicon on insulator ou FDSOI. Dans les circuits numériques synchrones modernes, une grande portion de la consommation totale du circuit provient de l'arbre d'horloge, et en particulier son extrémité : les bascules. Dès lors, l'architecture adéquate de bascules est un choix crucial pour atteindre les contraintes de vitesse et d'énergie des applications basse-consommation. Après un large aperçu de l'état de l'art, les bascules à impulsion explicite sont reconnues les plus prometteuses pour les systèmes demandant une haute performance et une basse consommation. Cependant, cette architecture est pour l'instant fortement utilisée dans les circuits à haute performance et pratiquement absente des circuits à basse tension d'alimentation, principalement à cause de sa faible robustesse face aux variations.Dans ce travail, la conception d'architecture de bascule à impulsion explicite est étudiée dans le but d'améliorer la robustesse et l'efficacité énergétique. Un large panel d'architectures de bascule, avec les fonctions reset et scan, a été comparé dans le domaine énergie-délais, à haute et basse tension d'alimentation, grâce à une méthodologie de dimensionnement des transistors. Il a été montré que la technique dite de « back bias », l'un des principaux avantages de la technologie FDSOI, permettait des meilleures performances en énergie et délais que la méthodologie de dimensionnement. Ensuite, comme le générateur d'impulsion est la principale raison de dysfonctionnement, nous avons proposé une nouvelle architecture qui permet un très bon compromis entre robustesse à faible tension et consommation énergétique. Une topologie de bascule à impulsion explicite a été choisie pour être implémentée dans un banc de registres et, comparé aux bascules maître-esclave, elle présente une plus grande vitesse, une plus faible consommation énergétique et une plus petite surface. / The explosion market of the mobile application and the paradigm of the Internet of Things lead to a huge demand for energy-efficient systems. To overcome the limit of Moore's law due to bulk technology, a new transistor technology has appeared recently in industrial process: the fully-depleted silicon on insulator, or FDSOI.In modern ASIC designs, a large portion of the total power consumption is due to the leaves of the clock tree: the flip-flops. Therefore, the appropriate flip-flop architecture is a major choice to reach the speed and energy constraints of mobile and ultra-low power applications. After a thorough overview of the literature, the explicit pulse-triggered flip-flop topology is pointed out as a very interesting flip-flop architecture for high-speed and low-power systems. However, it is today only used in high-performances circuits mainly because of its poor robustness at ultra-low voltage.In this work, explicit pulse-triggered flip-flops architecture design is developed and studied in order to improve their robustness and their energy-efficiency. A large comparison of resettable and scannable latch architecture is performed in the energy-delay domain by modifying the sizing of the transistors, both at nominal and ultra-low voltage. Then, it is shown that the back biasing technique allowed by the FDSOI technology provides better energy and delay performances than the sizing methodology. As the pulse generator is the main cause of functional failure, we proposed a new architecture which provides both a good robustness at ultra-low voltage and an energy efficiency. A selected topology of explicit pulse-triggered flip-flop was implemented in a 16x32b register file which exhibits better speed, energy consumption and area performances than a version with master-slave flip-flops, mainly thanks to the sharing of the pulse generator over several latches.

The current assembly procedure to install a trunnion and hub into a bascule bridge girder involves cooling the trunnion in liquid nitrogen and shrink fitting it into the hub. The resulting trunnion-hub assembly is then allowed to warm to room temperature. Next, the trunnion-hub assembly is cooled in the liquid nitrogen and shrunk fit into the girder. The cooling of the trunnion does not cause any problems, however, when the trunnion-hub assembly is cooled in the liquid nitrogen, the hub experiences a large thermal shock. These thermal shocks induce large stresses into the hub, which has been known to cause it to crack. This study investigates an innovative assembly procedure to install the trunnion-hub assembly into a bascule bridge girder. To avoid cooling the trunnion-hub assembly, the girder was heated instead. Laboratory testing and finite element analysis were used to determine if the girder could reasonably be heated to install the trunnion-hub assembly. An experiment was conducted to analyze the heating process that will be used. A rectangular steel plate ( 60"x60x"0.75") was used to model the girder in the lab. Inductance-heating coils were used to heat the steel plate to 350°F. The heating process was recorded using a data acquisition system with thermocouples and strain gages. ANSYS was the finite element analysis (FEA) program that was used to model the heating process of the plate. The FEA results from ANSYS were compared with the experimental results. This confirmed the parameters of the finite element analysis were correct. Those parameters were then used to model a full-scale girder. The feasibility of heating the girder was determined from the finite element analysis results. It was determined that heating the girder with 2250 BTU over min for 90 minutes, was sufficient energy for the assembly procedure to work. The girder was heated to a maximum temperature of 350°F and a 0.015" clearance was created for the assembly of the trunnion-hub. The finite element analysis of the girder showed that the placement of the heating coils on the girder was critical. Therefore this innovative assembly procedure can easily be accomplished, however, each girder must first be analyzed to determine the optimal heating configuration.

Nous avons étudié les fluctuations quantiques du champ électromagnétique ayant interagi avec un nuage d'atomes froids placé à l'intérieur d'une cavité optique. Proche de résonance, le milieu atomique se comporte comme un milieu non-linéaire en raison de la saturation de la transition optique. Lorsque le faisceau incident est polarisé linéairement, cette saturation se traduit par un effet de type Kerr sur le champ moyen et de type Kerr-croisé sur le mode vide orthogonal. Ces effets non-linéaires modifient les fluctuations de ces modes du champs. Nous avons alors pu observer la réduction du bruit sous la limite quantique standard sur ces deux modes.<br /> Nous avons interprété la réduction de bruit sur le mode vide orthogonal en terme de réduction du bruit de polarisation du faisceau. Les fluctuations de polarisation ont été caractérisées par la mesure des fluctuations des paramètres de Stokes.<br /> Par ailleurs, nous avons étudié les corrélations quantiques produites par le système. Ces corrélations ont été estimées à l'aide d'un critère de nonséparabilité, valable pour les variables continues. Nous avons alors montré que les modes polarisés à °45° (par rapport au champ moyen) sont intriqués en quadrature. Cette intrication a ensuite été utilisée pour produire deux faisceaux intriqués en polarisation.

Les régions polaires sont particulièrement touchées par le changement climatique actuel, en raison des mécanismes d'amplification qui y opèrent. Les forages de glace en Antarctique et au Groenland sont des témoins précieux des variations paléoclimatiques locales et donnent aussi accès à des informations sur les modifications environnementales des latitudes plus basses. Ce travail de thèse repose sur l'obtention d'informations délivrées par l'air progressivement emprisonné sous forme de bulle lors du processus de transformation de la neige en glace : la composition élémentaire et isotopique de l'air (N2, O2, Ar et Kr) et la concentration en méthane. Nos résultats permettent de progresser sur trois aspects différents mais intimement liés : (i) L'évolution passée de la structure des névés en Antarctique. La mesure des isotopes du krypton sur le forage profond de Dome C (EDC pour EPICA Dome C) nous permet de mettre en évidence qu'une zone convective de l'ordre de 20-50 m a pu se développer dans le névé en période glaciaire. L'étude conjointe des profils isotopiques de l'azote ("15N) mesurés sur les forages EPICA Dronning Maud Land (EDML) et TALDICE suggèrent que l'évolution de la structure du névé des deux sites ne répond plus de manière simple aux changements du taux d'accumulation en surface lorsque celui-ci dépasse un seuil de 5 ±1.5 cm eq. glace an- 1. (ii) La datation des forages glaciologiques. Nous avons exploité le premier enregistrement de "O2/N2 produit entre 300 000 et 800 000 ans sur l'air piégé dans la glace de EDC. Alors qu'il semble délicat d'utiliser ce signal pour construire une nouvelle datation par calage orbital de ce forage, en particulier pour les périodes de faible excentricité, le "O2/N2 se révèle être un outil pertinent pour tester les limites et les incertitudes de la datation actuelle du forage (EDC3). L'utilisation conjointe des isotopes de l'oxygène atmosphérique et du méthane nous permet d'établir une synchronisation des forages de EDML (Antarctique) et de NorthGRIP (Groenland) couvrant le début de la dernière période glaciaire (75 000-123 000 ans) avec une incertitude inférieure à 400 ans. (iii) Cette datation relative nous permet de décrire les variations climatiques rapides au début de la dernière période glaciaire au Groenland et en Antarctique. Nous mettons en évidence une variabilité climatique sub-millénaire superposée à la succession classique des évènements de Dansgaard Oeschger, i.e. des évènements précurseurs aux évènements rapides, des rebonds climatiques en fin d'interstade. Nous démontrons que le mécanisme de bascule bipolaire entre le Groenland et l'Antarctique est également opérationnel à l'échelle sub- millénaire. Une étude multiparamétrique sur le premier événement abrupt enregistré dans la glace de NorthGRIP (DO25) montre que cet événement caractérise la transition entre la dernière période interglaciaire et la mise en place d'une variabilité abrupte couplant les hautes et les basses latitudes. L'ensemble de nos résultats établit un lien étroit entre la dynamique climatique rapide à l'échelle millénaire et les composantes à évolution lente qui imposent l'état de base du système climatique (configuration orbitale, volume des glaces).

La présente thèse se propose de résoudre les problématiques de facilités de contrôle optique d'un document de sécurité pourvu d'un hologramme par l'application d'une structure optique complexe mettant en œuvre les modes de plasmons de surface. Dans une partie dédiée nous démontrerons l'adaptation de la transmission extraordinaire plasmonique à travers une couche métallique continue ; un concept de sécurité sera aussi présenté permettant l'observation et l'authentification de l'effet transmissif. Dans une autre partie nous présentons un effet de réflexion plasmonique extraordinaire. En lieu et place des phénomènes classiques d'absorption sur une couche métallique épaisse, nous présentons un phénomène que nous avons nommé balance énergétique à médiation plasmonique. Cet effet est bien évidemment mis en évidence à travers un concept final adapté au domaine de l'optique de sécurité