In the last decades, the increase of industrial activities and of the request for the world food requirement, the intensification of natural resources exploitation, directly connected to pollution, have aroused an increasing interest of the public opinion towards initiatives linked to the regulation of food production, as well to the institution of a modern legislation for the consumer guardianship. This work was planned taking into account some important thematics related to marine environment, collecting and showing the data obtained from the studies made on different marine species of commercial interest (Chamelea gallina, Mytilus edulis, Ostrea edulis, Crassostrea gigas, Salmo salar, Gadus morhua). These studies have evaluated the effects of important physic and chemical parameters variations (temperature, xenobiotics like drugs, hydrocarbons and pesticides) on cells involved in the immune defence (haemocytes) and on some important enzymatic systems involved in xenobiotic biotransformation processes (cytochrome P450 complex) and in the related antioxidant defence processes (Superoxide dismutase, Catalase, Heat Shock Protein), from a biochemical and bimolecular point of view. Oxygen is essential in the biological answer of a living organism. Its consume in the normal cellular breathing physiological processes and foreign substances biotransformation, leads to reactive oxygen species (ROS) formation, potentially toxic and responsible of biological macromolecules damages with consequent pathologies worsening. Such processes can bring to a qualitative alteration of the derived products, but also to a general state of suffering that in the most serious cases can provoke the death of the organism, with important repercussions in economic field, in the output of the breedings, of fishing and of aquaculture. In this study it seemed interesting to apply also alternative methodologies currently in use in the medical field (cytofluorimetry) and in proteomic studies (bidimensional electrophoresis, mass spectrometry) with the aim of identify new biomarkers to place beside the traditional methods for the control of the animal origin food quality. From the results it’s possible to point out some relevant aspects from each experiment: 1. The cytofluorimetric techniques applied to O. edulis and C. gigas could bring to important developments in the search of alternative methods that quickly allows to identify with precision the origin of a specific sample, contributing to oppose possible alimentary frauds, in this case for example related to presence of a different species, also under a qualitative profile, but morpholgically similar. A concrete perspective for the application in the inspective field of this method has to be confirmed by further laboratory tests that take also in account in vivo experiments to evaluate the effect in the whole organism of the factors evaluated only on haemocytes in vitro. These elements suggest therefore the possibility to suit the cytofluorimetric methods for the study of animal organisms of food interest, still before these enter the phase of industrial working processes, giving useful information about the possible presence of contaminants sources that can induce an increase of the immune defence and an alteration of normal cellular parameter values. 2. C. gallina immune system has shown an interesting answer to benzo[a]pyrene (B[a]P) exposure, dose and time dependent, with a significant decrease of the expression and of the activity of one of the most important enzymes involved in the antioxidant defence in haemocytes and haemolymph. The data obtained are confirmed by several measurements of physiological parameters, that together with the decrease of the activity of 7-etossi-resourifine-O-deetilase (EROD linked to xenobiotic biotransformation processes) during exposure, underline the major effects of B[a]P action. The identification of basal levels of EROD supports the possible presence of CYP1A subfamily in the invertebrates, still today controversial, never identified previously in C. gallina and never isolated in the immune cells, as confirmed instead in this study with the identification of CYP1A-immunopositive protein (CYP1A-IPP). This protein could reveal a good biomarker at the base of a simple and quick method that could give clear information about specific pollutants presence, even at low concentrations in the environment where usually these organisms are fished before being commercialized. 3. In this experiment it has been evaluated the effect of the antibiotic chloramphenicol (CA) in an important species of commercial interest, Chamelea gallina. Chloramphenicol is a drug still used in some developing countries, also in veterinary field. Controls to evaluate its presence in the alimentary products of animal origin, can reveal ineffective whereas the concentration results to be below the limit of sensitivity of the instruments usually used in this type of analysis. Negative effects of CA towards the CYP1A- IPP proteins, underlined in this work, seem to be due to the attack of free radicals resultant from the action of the antibiotic. This brings to a meaningful alteration of the biotransformation mechanisms through the free radicals. It seems particularly interesting to pay attention to the narrow relationships in C. gallina, between SOD/CAT and CYP450 system, actively involved in detoxification mechanism, especially if compared with the few similar works today present about mollusc, a group that is composed by numerous species that enter in the food field and on which constant controls are necessary to evaluate in a rapid and effective way the presence of possible contaminations. 4. The investigations on fishes (Gadus morhua, and Salmo salar) and on a bivalve mollusc (Mytilus edulis) have allowed to evaluate different aspects related to the possibility to identify a biomarker for the evaluation of the health of organisms of food interest and consequently for the quality of the final product through 2DE methodologies. In the seafood field these techniques are currently used with a discreet success only for vertebrates (fishes), while in the study of the invertebrates (molluscs) there are a lot of difficulties. The results obtained in this work have underline several problems in the correct identification of the isolated proteins in animal organisms of which doesn’t currently exist a complete genomic sequence. This brings to attribute some identities on the base of the comparison with similar proteins in other animal groups, incurring in the possibility to obtain inaccurate data and above all discordant with those obtained on the same animals by other authors. Nevertheless the data obtained in this work after MALDI-ToF analysis, result however objective and the spectra collected could be again analyzed in the future after the update of genomic database related to the species studied. 4-A. The investigation about the presence of HSP70 isoforms directly induced by different phenomena of stress like B[a]P presence, has used bidimensional electrophoresis methods in C. gallina, that have allowed to isolate numerous protein on 2DE gels, allowing the collection of several spots currently in phase of analysis with MALDI-ToF-MS. The present preliminary work has allowed therefore to acquire and to improve important methodologies in the study of cellular parameters and in the proteomic field, that is not only revealed of great potentiality in the application in medical and veterinary field, but also in the field of the inspection of the foods with connections to the toxicology and the environmental pollution. Such study contributes therefore to the search of rapid and new methodologies, that can increase the inspective strategies, integrating themselves with those existing, but improving at the same time the general background of information related to the state of health of the considered animal organism, with the possibility, still hypothetical, to replace in particular cases the employment of the traditional techniques in the alimentary field.

Il presente studio ha a tema la versione araba del testo greco noto tra gli studiosi come De aeternitate mundi, Sull’eternità del cosmo, del filosofo Proclo (410-485 d. C.). Scopo della ricerca è mettere in luce la ricezione dottrinale e linguistica degli argomenti eternalisti procliani in traduzione araba. In arabo ci sono pervenute due traduzioni di parte degli argomenti eternalisti di Proclo, un fatto di grande interesse perché essi andarono ad alimentare, insieme a quelli creazionisti dell’avversario Filopono, uno dei primi dibattiti su cui le opinioni nel panorama intellettuale arabo musulmano si divisero: l’origine del mondo. Un confronto linguistico tra le due versioni del testo procliano mostra in primis che la prima traduzione, anonima, condivide una grammatica dottrinale e linguistica con le traduzioni nate nel cosiddetto “circolo di al-Kindi” (IX secolo), ed è pertanto riconducibile al filosofo arabo, per quanto sostenitore dell’inizio temporale del cosmo. Elementi linguistici e stilistici rendono inoltre ragione dell’«eloquenza», fasāḥa, che rese famoso il presunto traduttore della seconda versione degli argomenti procliani, Ishaq ib Hunayn (m. 911), ma allo stesso tempo mostrano come egli erediti le elaborazioni dottrinali della traduzione anteriore, probabilmente all’origine dell’interesse per gli argomenti procliani e per una loro seconda traduzione in epoca ad essa successiva. / This work focuses on the Arabic translation of the Greek treatise known as De aeternitate mundi, On the eternity of the world, written by the philosopher Proclus in the fifth century a.d. Its purpose is to enlight the doctrinal and linguistic reception of Proclus’ proofs of the eternity of the world in their Arabic translations. First, the interest in the mentioned proofs is due to the fact that they are considered, together with the opponent Giovanni Filopono’s creationist ones, one of the main sources for the initial debate for natural theology and philosophy, where opinions of Muslim divided: the inquiry concerning whether the world is eternal or had a beginning. A linguistic comparison between the two translation shows that the most ancient translation shares a common doctrinal and linguistic grammar with the texts borne in the so called “Circle of al-Kindi”, (IX century). Therefore, it can be linked to the Arabic philosopher, although he was in support of the temporal beginning of the world. In addition to that, it apparently gives reasons for the fasāḥa, “eloquence”, that made famous the presumed translator of the second version of the Arabic proclian proofs: Ishaq ibn Hunayn (m. 911), but at the same time shows that he inherited the doctrinal contents that the first translator developed in his version. It is this doctrinal development that apparently raised the interest for the proclian text and that justifies their second translation.

Cette thèse, "Création à partir de l'impact", nous propose une réflexion élaborée à partir d'un point de vue pratique, sur l'effet créatif qu'engendre l'impact dans l'art du 20éme siècle jusqu'à aujourd'hui. L'impact sur la matière agit comme un agent de transformation qui mène à une redécouverte du matériau, permettant ainsi une relation intrinsèque avec la matière. C'est avec le regard intérieur de l'artiste que l'auteur nous fait découvrir son propre processus créatif développé à partir de l'impact. L'impact est une transmission d'énergie qui mène au-delà des choses matérielles, il est ce par quoi l'artiste peut entendre les résonances venues de l'intérieur, comme une nouvelle identité à découvrir. L'impact devient ainsi, une façon de passer de l'extérieur vers l'intérieur. Il permet de dépasser l' aspect visuel et matériel des choses pour en découvrir l'essence même. Nous y voyons comment certains événements de l'histoire ont créé des impacts, provoquant des réactions stimulant la créativité des artistes. Les impacts venus de partout, engendrent des transformations de la matière, de la pensée humaine et de la vie elle-même. L'œuvre d'art s'érige comme un phare à la mémoire et à la pensée de l'homme, une métaphore de l'énergie de la vie qui évolue. / Entitled "Creation from the impact", this thesis is intended to open up a reflection from a practical point of view on the creative effect provided by the impact on twentieth century art and beyond. Impact on matter works as a transformation agent; it leads to rediscover the material, allowing then an intrinsic relationship with matter. It is with the internal gaze of the artist that the author is willing to make discover her own creative process rooted in impact. Impact is an energy flow which leads beyond material things; through it the artist is able to hear the echo coming from the inside, as a new identity to be discovered. Impact becomes then a way leading from the outside to the inside. The visual and material aspects are overstepped in order to discover the very essence of things. One can understand how certain historical events have produced impacts and subsequently reactions stimulating the artists' creativity. Coming from everywhere, impacts tend to transform matter, human thinking and even life itself. The work of art rises as a light illuminating human memory and thinking, as a metaphor of the energy of the life process.

Chaque division cellulaire requiert une duplication précise du génome. Des dizaines de milliers de sites d’initiation de la réplication d’ADN (origines de réplication) sont impliqués dans la réplication complète du génome humain. L’activation des origines de réplication est régulée précisément et des études génomiques extensives ont démontré la présence de caractéristiques génomiques associées à l’activation des origines de réplication. Le complexe de pré-réplication (pre-RC) est la base de l’initiation de la réplication et consiste en deux sous-complexes majeurs : l’ « origin recognition complex » (ORC) qui interagit directement avec l'ADN et est nécessaire pour recruter le second sous-complexe, les hélicases Mcm2 7, qui sont responsables de l'initiation de la réplication. La régulation de l’assemblage du pre-RC est bien étudiée, mais les caractéristiques de la chromatine qui déterminent le positionnement du pre-RC sur le génome restent peu connues. Les études génomiques par immuno-précipitation de la chromatine et séquençage à haut débit (ChIP-seq) des pre-RCs sont rares et jusqu’à aujourd’hui seulement disponibles pour ORC. Du fait que Mcm2-7 migre de son site de chargement initial, il est crucial d'obtenir des informations sur le positionnement des Mcm2-7 pour la compréhension complète de la régulation de la réplication. Ce travail présente la première analyse génomique par méthode ChIP-seq des deux sous-unités majeures du pre-RC, ORC et Mcm2-7, dans la lignée cellulaire de lymphome de Burkitt Raji infectée par le virus d’Epstein-Barr (EBV). La présence du génome d’EBV permet d'avoir un contrôle interne de la qualité de nos expériences, en comparant les positions de pre-RC déterminées avec des positions du pre-RC précédemment publiées. Sur le génome humain, les résultats de séquençage du pre-RC corrèlent bien avec des zones de réplication active. De façon intéressante, les zones de terminaison de la réplication étaient spécifiquement bas en pre-RC, spécialement en Mcm2-7. La localisation des sites d'initiation de la réplication identifiés est généralement bien corrélée avec les sites de transcription active. En effet, des sites d’assemblage du pre-RC de haute affinité sont localisés préférentiellement en voisinage de sites de transcription active, ce qui est possiblement dû à l’accessibilité de la chromatine dans ces régions. La fixation de Mcm2-7 fluctue de façon dépendante du cycle cellulaire, ce qui suggère des translocations de Mcm2 7 en G1, probablement dépendantes de la machinerie active de la transcription. Ces résultats indiquent que les positions de ORC et Mcm2-7 sont principalement dépendantes de l’accessibilité de la chromatine avec un accès privilégié dans la chromatine active et Mcm2 7 étant le déterminant majeur de l’initiation de la réplication. Au sein de l'hétérochromatine, ORC est enrichi dans des zones associées avec l'histone modifié H4K20me3. Cependant, cet enrichissement est moins important pour les Mcm2-7. En utilisant un système de réplication basé sur des plasmides, nous avons démontré que l’association d'ORC et H4K20me3 favorise l’assemblage du pre-RC et l’initiation de la réplication. Cette observation suggère que l’interaction ORC-chromatine est le déterminant majeur de la régulation de la réplication d’ADN au sein de l’hétérochromatine. En conclusion, cette étude propose deux mécanismes différents de la régulation de l'assemblage du pre-RC dépendants de l’environnement de la chromatine. / With every cell division, the genome needs to be faithfully duplicated. Tens of thousands of DNA replication initiation sites (origins of replication) are involved in replicating the human genome. Origin activation is precisely regulated and extensive genome-wide studies found association of origin activation to several different genomic features. The pre-replication complex (pre RC) is the basis for replication initiation and consists of two major subcomponents: the origin recognition complex (ORC) binds DNA and is required for loading of the second component, Mcm2-7 helicases, which initiate DNA replication. Regulation of pre-RC assembly is well studied, however, chromatin features driving pre RC positioning on the human genome remain largely unknown. Genome-wide pre-RC chromatin immunoprecipitation experiments followed by sequencing (ChIP-seq) studies are rare and so far only performed for ORC. As Mcm2-7 can translocate from their initial loading site, information about Mcm2-7 positioning are required for full understanding of DNA replication regulation.This work presents the first genome-wide ChIP-seq analysis of the two major pre-RC subcomponents ORC and Mcm2-7 in the Epstein-Barr virus (EBV) infected Burkitt’s lymphoma cell line Raji. Successful ChIPs were validated on the EBV genome by comparing obtained pre RC positions with already existing pre-RC ChIP-on chip data. On the human genome, pre-RC sequencing results nicely correlated with zones of active replication. Interestingly, zones of replication termination were specifically depleted from pre-RC components, especially from Mcm2 7. Active DNA replication is known to correlate with active transcription. Indeed, strong pre-RC assembly preferentially occurred at sites of active transcriptional regulation, presumably determined by chromatin accessibility. Strong Mcm2-7 binding thereby fluctuated cell cycle-dependently, arguing for Mcm2-7 translocations during G1, possibly depending on the active transcriptional machinery. These results indicate ORC and Mcm2-7 positions being mainly dependent on chromatin accessibility in active chromatin, with Mcm2-7 being the major determinant of replication initiation. In heterochromatin, ORC was enriched at H4K20me3 sites, while Mcm2-7 enrichment was less prominent. Employing a plasmid-based replication system, ORC association to H4K20me3 was proven to promote successful pre-RC assembly and replication initiation, situating direct ORC-chromatin interactions being the major determinant for DNA replication regulation in heterochromatin. Taken together, this study proposes two different modes of pre-RC assembly regulation depending on chromatin environment.

Les découvertes de systèmes hydrothermaux marins ont permis de dire qu'ils réunissaient les conditions favorables à l'apparition des premières formes de vie car des concentrations appréciables en N2, CO2, H2S, CH4, C2H6 et C3H8 ainsi que des quantités détectables (10-9 mol) de n-alcanes de poids moléculaire élevé (C16-C29) ont été mesurées dans les fluides hydrothermaux de la ride médio-Atlantique. Les premières formes de vie étaient sans doute des êtres microbiens simples et unicellulaires qui ont pu trouver dans les composés organiques l'énergie nécessaire à leur évolution. Les systèmes hydrothermaux marins peuvent avoir constitués un environnement favorable à l'apparition de la vie car ces systèmes sont caractérisés par des fumeurs noirs et des fumeurs blancs avec un écosystème indépendant de l'énergie solaire où vivent les organismes les plus primitifs trouvés dans les environnements actuels, les hyperthermophiles. Ces arguments sont très importants en ce qui concerne les conditions qui régnaient à l'Archéen. Les systèmes hydrothermaux Archéens sont les seuls environnements où la vie primitive a pu être protégée des impacts des météorites et de la vaporisation partielle de l'océan. Ces systèmes sont compatibles avec l'origine et l'évolution de la vie. Les études expérimentales, sur la synthèse et la stabilité des composés prébiotiques dans des conditions hydrothermales sont couplées aux études théoriques en thermodynamique permises par les travaux de mesure expérimentales. L'origine abiogéniques des composés organiques azotés dans les conditions hydrothermales est primordiale dans l'histoire de la Terre / Hydrothermal Systems discovery involve it gather favorable conditions to act for the appearing of the first living shape, because significant concentrations in N2, CO2, H2S, CH4, C2H6 and C3H8 and detectable quantities (10-9 mol) of heavy weights n-alcanes (C19-C29) were measured in hydrothermal fluids of the mid-Atlantic ridge. The first living shape were without no doubt simple or unicellular microbes being which finding in organic compounds the satisfying energize for their evolution. Hydrothermal systems could have constitute a favorable environment for the appearing of life because these systems are characterized by black smokers and white smokers with an ecosystems independent of solar energize where the most primitives organisms live, found in actual environments, the hyperthermophiles. These arguments are very important concerning the conditions ruling in Archean. The hydrothermal systems of Archean were the only environment where the primitive life was protect of meteoritic impact and partial vaporization of the ocean. These systems are compatible with origin and evolution of life. The experimental study, on the synthesis and stability of prebiotic compounds in hydrothermal conditions are gathered with thermodynamic studies permit by the works of experimental measures. Abiogenic origin of nitrogen organic compounds in hydrothermal conditions is primordial in the history of the Earth

Cette thèse revient sur les migrations diolas et les évolutions identitaires qui accompagnent ces populations au contact d’autres groupes, et à la faveur des déplacements de personnes.L'immigration diola très peu étudiée, est abordée dans cette thèse, à travers les associations, informelles ou celles qui relèvent de la loi 1901, pour celles légitimées par l’autorité préfectorale en France.Ces regroupements constituent un creuset par excellence, pour analyser les enjeux de pouvoirs chez des populations héritières d'une autre forme de pouvoir. Les liens envers le lieu d'origine questionnent au-delà des parcours migratoires, les histoires, les politiques et les identifications de ces immigrés et de leurs descendants.Les enjeux de pouvoir et les interactions entre les immigrés et leurs parents restés au pays seront donc analysées sous le prisme des migrations et des coopérations bilatérales. Le contexte politique et économique est un facteur très important dans cette étude.Mots clés : Migrations, enjeux de pouvoirs, Diolas, associations, identités. / This thesis deals with the diola migrations and the evolutions of their identities when they meet other groups by moving.The diola immigration, few studied, is considered in this thesis through the unformal associations or the legal associations ruled by the law of 1901 legitimated by French local authorities. These communities are the ideal place to analyze the challenges of power among people who have been ruled by other kinds of power. The links with the country of origin are questioned out of the migratory trajects and the stories, the policies and the didentifications of these immigrants and their descents are also studied.The power challenges and the interactions between the immigrants and their relatives living in the country of origine will be analyzed through the migrations and the bilateral cooperations. The politicla and economic context is an important factor in this research.Key words : migrations, power challenges, Diola, associations, identities

Depuis la découverte de la chiralité moléculaire par Pasteur il y a plus de 150 ans, l'origine de l'homochiralité de la vie reste un mystère non résolu et troublant, qui remonte probablement à l'origine de la vie elle-même. Cette énigme a récemment été recensée dans Nature comme étant l’une des cinq plus grandes énigmes non résolues par la science.Aujourd'hui il existe deux façons d’aborder le problème de l'origine de l'asymétrie moléculaire impliquant des scénarios soit déterministes soit aléatoires. Ces derniers étant basés sur la résolution spontanée des énantiomères, et sont donc impossible à tester. En revanche, les théories déterministes peuvent être confrontées à l’expérience afin notamment de valider la reproductibilité de leur influence chirale.Le présent manuscrit est une synthèse bibliographique et expérimentale mettant en évidence les interactions de la LPC avec des molécules chirales dans le cadre de l’origine de l’homochiralité de la vie. Ces travaux ont pour but de mieux comprendre les propriétés chiroptiques de molécules chirales ainsi que de déterminer les espèces chirales susceptibles d'être présentes dans la glace cométaire / Since the Pasteur’s discovery of chirality more than 150 years ago, the origin of homochirality remains to be an unresolved mystery, which is probably linked to the origin of life-itself. This puzzle was named by the journal Nature as one of the five biggest unresolved puzzles in modern science.Today there exist two ways to address the question of the origin of molecular homochirality. It implies either deterministic or chance scenario. The latest is based on the spontaneous resolution of enantiomers by phase transition, and in consequence, it cannot be tested. On the other hand, deterministic theories can be subjected to experimental confirmation, since if there was, in fact, a chiral influence that imposed its chirality this should in principle be reproducible.The presented manuscript is a synthesis of bibliographic research and experimental studies that focus on the interaction of CPL with chiral molecules which are put in the context of the origin of homochirality of life. This work is aiming to advance our understanding of chiroptical properties of chiral molecules as well as to determine chiral species susceptible to be present in cometary ice

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Les dix premières années de l'œuvre de Jacques Derrida, soit de la traduction et de l'introduction à L'origine de la géométrie de Husserl (1962) jusqu'à Marges de la philosophie (1972), développent progressivement la «pensée» de la différance. La visée centrale de ce mémoire consiste à décrire la genèse de la différance en insistant sur la déconstruction de l'origine. Nous posons deux questions : 1) de quelle manière Derrida analyse-t-il le concept d'origine présent dans la philosophie de la présence?; et 2) de quelle manière -à partir de cette analyse du concept d'origine- en vient-il à proposer le « concept » de différance? Nous tenterons donc de démontrer que ce n'est que par le biais de la déconstruction du concept d'origine et par sa rayure que Derrida en vient à émettre sa « philosophie » de la différance.

Ce mémoire revisite à l’aide de méthodes d’économétrie spatiale le modèle gravitaire PODM (Passenger Origin-Destination Model) que Transports Canada utilise pour prédire le trafic aérien domestique de passagers. Différents modèles spatiaux de panel sont estimés par maximum de vraisemblance et par la méthode des moments. Les résultats montrent que l’approche traditionnelle ne détecte pas d’effets de la distance entre l’origine et la destination sur le volume du trafic intérieur de passagers. Ce sont les caractéristiques de la région d’origine et de destination (PIB, revenu disponible, population) et les caractéristiques du trajet (prix moyen du billet, nombre de vols offerts) qui sont les déterminants les plus importants des flux de passagers. Dans les modèles spatiaux explorés, les interactions spatiales se révèlent d’importants déterminants aux côtés des caractéristiques locales. La prise en compte de ces effets spatiaux pourrait permettre d’améliorer les prévisions de trafic de passagers au Canada. Mots clés : interactions spatiales, données de panel, maximum de vraisemblance, méthodes des moments.