This study aimed at providing a thorough understanding of temporal and spatial variations of VOCs and underlying factors in different microenvironments in two different urban atmospheres, with different degrees of regulatory enforcement. The VOC data were collected in field campaigns conducted in Ankara, Turkey, and Ottawa, Canada over the years 2000-2004. Insight into the sources of VOCs in different urban atmospheres was sought by using three commonly used receptor models namely / Positive Matrix Factorization (PMF), Chemical Mass Balance (CMB) Model and Conventional Factor Analysis (CFA). Motor vehicle related source profiles were developed to use in receptor modeling. Motor vehicles are the most abundant VOC sources with about 60% and 95% contributions to ambient levels in Ankara and Ottawa, respectively. Residential heating (31%) during winter season, biogenic (9%) and architectural coating (12%) emissions during summer season and solvent use (about 12%) emissions are the next abundant VOC sources in Ankara. In addition, a new method to estimate the contribution of sources from wind sectors in urban atmosphere was developed and implemented in this study. The comparison of the results of these two cities demonstrated the influence of control measures on ambient levels and sources of VOCs observed in different urban atmospheres. VOC levels in Ankara exceed EU levels and they are about factor of two higher than that are measured in Ottawa owing to lack of implementation of emission control regulations for VOCs in Ankara compared to well adopted regulations in Ottawa.

Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic air pollutants formed during incomplete combustion and are ubiquitously distributed in the environment. To determine particle-bound PAHs in archived PM2.5 samples taken with low flow rate in Atlanta, a sensitive and robust method was developed for measuring 28 PAHs and methyl PAHs in PM samples using isotope dilution gas chromatography/high resolution mass spectrometry (GC/HRMS). The method was then used to analyze PM2.5 samples collected at three sites (rural, urban, suburban-highway) from the Assessment of Spatial Aerosol Composition in Atlanta (ASACA) network. Distinct seasonal and spatial variations were observed in PAH concentration. Particle-bound PAH levels were significantly higher in winter than in summer. The suburban-highway site had higher PM2.5-bound PAH concentration than did the urban site, and the rural site had the lowest PAH levels. Retene, a proposed biomass burning tracer, captured both the high leaves-grasses-bushes-branches burning season and the high wood burning months, suggesting that it might be a better marker for all biomass burning, while potassium ion might be a more specific tracer for wood burning. Human exposure to PAHs can be assessed by characterizing their hydroxy PAH (OH-PAH) metabolites in urine samples. A method was developed to measure 24 urinary OH-PAHs, metabolites of 8 parent PAHs, using enzymatic de-conjugation, automatic liquid-liquid extraction, and GC/HRMS. A study was then carried out to evaluating the variability of the urinary biomarker levels in a non-occupationally exposed non-smoking reference group. Levels of urinary PAH metabolites varied widely both within-subject and between-subjects and the within-day variance far exceeded the between-day variance. There were also considerable temporal correlations for these biomarkers. Sample size calculations were conducted and taking 24-hour voids would require the least number of subjects, which should be considered during epidemiological study design. Finally, a study was conducted to evaluate exposure to ambient PAHs in an urban setting among 8 non-occupationally exposed non-smoking volunteers employing both personal air sampling and urine biomonitoring. PAH levels varied largely in air samples taken at home, at work, and while driving or jogging. Monitoring urinary OH-PAH levels can capture both inhalation and dietary exposures. Total inhaled PAH was correlated with total excreted OH-PAHs, suggesting that by combining personal air sampling and biomonitoring, exposure to environmental PAHs can be well characterized even for low-level exposure.

The spatial data community relies on the quality of its data. This research investigates new ways of storing and retrieving spatial data quality information in databases. Given the importance of features and sub-feature variation, three different data quality models of spatial variation in quality have been identified and defined: per-feature, feature-independent and feature-hybrid. Quality information is stored against each feature in the per-feature model. In the feature-independent model, quality information is independent of the feature. The feature-hybrid is derived from a combination of the other two models. In general, each model of spatial variation is different in its representational and querying capabilities. However, no model is entirely superior in storing and retrieving spatially varying quality. Hence, an integrated data model called as RDBMS for Spatial Variation in Quality (RSVQ) was developed by integrating per-feature, feature-independent and feature-hybrid data quality models. The RSVQ data model provides flexible representation of SDQ, which can be stored alongside individual features or parts of features in the database, or as an independent spatial data layer. / The thesis reports on how Oracle 10g spatial RDBMS was used to implement this model. An investigation into the different querying mechanisms resulted in the development of a new WITHQUALITY keyword as an extension to SQL. The WITHQUALITY keyword has been designed in such a way that it can perform automatic query optimization, which leads to faster retrieval of quality when compared to existing query mechanism. A user interface was built using Oracle Forms 10g which enables the user to perform single and multiple queries in addition to conversion between models (example, per-feature to feature-independent). The evaluation, which includes an industry case study, shows how these techniques can improve the spatial data community’s ability to represent and record data quality information.

Cette thèse se propose de questionner, sous l’angle du langage, le phénomène de l’idéologie en partant de la francographie négro-africaine. Caractérisant cette dernière, nous restituons les temps forts de sa construction, tumultueuse, en pratique professionnelle organisée, pour aboutir à l’hypothèse que les idéologèmes du texte porteraient en premier sur une interprétation du vécu sociopolitique du continent. À partir de ce point, et compte tenu de l’ubiquité de notre sujet, nous tentons de circonscrire un cadre opératoire de nœuds idéologiques dans le texte. Pour ce faire, nous avons recours à l’analyse du discours, surtout avec ses notions de pratique et de formation discursives, ainsi qu’avec celle d’habitus, développée par Bourdieu pour rendre compte d’un système de signes culturellement et socialement conditionnés. Ceci écarte l’immanence structuralise et permet une porosité de l’analyse dans la perspective d’un aller-retour permanent entre l’idéologie de l’auteur et celle de son personnel en texte. C’est sur ces deux plages, et sur les deux plans (le plus fondamental de représentation du monde, et le plus calculé, le plus stratégique, voire le plus polémique) du processus idéologique, que nous parvenons à bâtir la structuration de notre thèse. Nous analysons ainsi, sous le couvert de la lexicologie, La caractérisation, La description et La créativité lexicale, qui prennent globalement en charge les artifices d’agencements discursifs des locuteurs pour donner à voir les êtres et les choses. Il en découle une vision plutôt négative du cosmos chez les personnages mis en scène, même si certains auteurs ont su relever l’image de l’Afrique, aussi bien auprès des Occidentaux que chez les Africains eux-mêmes. Dans la seconde partie, qui se penche sur La structuttion scénographique, nous analysons particulièrement le sens de l’énoncé à travers son énonciation, la (mise en) scène tant externe qu’interne de l’énonciation des auteurs et de leurs personnels. Éprouvant positivement le critère linguistique de la formation discursive de la graphie, Les représentations linguistiques montrent à quel point la langue française continue de hanter les esprits, plus d’un demi-siècle après l’occupation coloniale, que ce soit en vrai ou en faux, i.e comme soumis à un stratagème de positionnement dans la légende. Une étude de l’énonciation textuelle, par Les discours rapportés, Les déictiques et La temporalité narrative, montre comment les sujets parlant conçoivent l’altérité ou l’identité, comment ils migrent, selon le besoin de la cause, de l’énonciation singulière à l’énonciation universelle et vice-versa, comment ils manipulent l’énonciation d’autrui pour la soumettre à la leur. Les auteurs dénoncent, surtout sur le plan politique, un laxisme et un amour pitoyable de l’immédiateté.La francographie négro-africaine apparaît comme un champ de batailles idéologiques variées, que ce soit entre les écrivains, les politiques et les partenaires de l’édition, ou bien entre les écrivains et les lecteurs, africains ou francophones. Même si ces derniers ne répondent pas aux auteurs dans le texte, ou ne leur répondent pas tout simplement, les débats, les perceptions qui s’entretiennent de part et d’autre des deux camps se lisent en filigrane. / This thesis, entitled The ideology of the text: semiolinguistic analysis of the negro-African francography, is attempting a scrutiny of ideology in the novel. Characterizing what is known as francography, we restore the main events of its tumultuous development into the organized professional activity that it is today. We thus postulate that ideologems in the text initiate an interpretation of the sociopolitical situation in Africa. Trying to resolve the ubiquity of ideology in language, we manage to circumscribe a frame of study to spot the manifestations of our topic in the text. For that purpose, we recourse to discourse analysis, especially its concepts of discursive practice and discursive formation. The notion of habitus, developed by Bourdieu, also contributed to state systems of signs that are culturally and socially determined in the African literary field, as well as it deviated the structuralist immanence of text theories. This deviation led to an efficient switch between the ideology of the authors and that of their characters or narrators. It is on these two lines and on the double aspect (the basic one of thoughts and viewpoints, and the most strategic or controversial one) of the ideological action that we come to build the frame of the thesis. Through a lexicological study (Characterization, Description and Lexical creativity), we examine the lexical combinations constructed by the speakers to represent things and beings according to their judgments. It emerges from this that enunciators have a rather negative representation of their environment, even though some authors succeed in raising the image of Africa. In the second section of the theses, based on Thescenographic structuration, we scrutinize the sense of the utterance according to its enunciation, as well as we consider both the internal and the outside stage/staging of the various protagonists of the communication. Confirming the statement that African writers, more than fifty years after colonization, are still concerned with the linguistic question, The Linguistic representations illustrate the use of various conceptions of French that writers perform, either to simply get ordinary representations to reverberate across the literary field, either as a strategy to make their mark on a topic that has always been very successful. The study of the text enunciation, through Reported speech, Deixis and Narrative temporality, reveals how speakers/thinkers conceive otherness and identity, how they switch, according to their interests, from a singular to a universal reference and vice versa, how they manipulate the other’s enunciation to serve their viewpoints. In the aggregate, authors of the corpus denunciate an excessive free-and-easy political attitude and a pernicious propensity for immediacy.The negro-African francography turns out to be a field of various ideological battles, both for writers, political and publishing protagonists, on the one hand, and, on the other hand, for writers and readers, whether the latter are African or Europeans. It does not matter much that readers don’t answer writers back in the text, or don’t even simply retort; what is certain is that the battles and reciprocal perceptions over both sides are palpable in the text.

Ces travaux approchent la question de la diversité dans la Francophonie sur la base de constructions verbales en Côte d’Ivoire. L’étude du sous-corpus écrit montre ainsi que le fait que 232 sur 400 étudiants soient concernés par des « écarts » de constructions verbales relève essentiellement d’une « connaissance approximative de la valence du verbe employé ». Quant à l’interférence du français ivoirien ordinaire, elle diminue progressivement jusqu’à la Licence (Licence 3) avant de présenter une chute significative en Maîtrise (Master 1). L’analyse du sous-corpus oral souligne ensuite des constructions verbales typiques du français ivoirien ordinaire. Nous en déduisons que les étudiants des années supérieures manient mieux le français standard, et la variation en général, que ceux des premières années. Nous proposons dès lors une didactique du français de Côte d’Ivoire jetant les bases pédagogiques de la variation du français en Côte d’Ivoire tout en insistant sur l’intérêt d’une norme grammaticale pour l’ensemble du monde francophone. / These studies approach the issue of diversity in the Francophonie on the basis of verbal constructions in Côte d'Ivoire. The study of written sub-corpus shows that the fact that 232 out of 400 students are involved with "gaps" in verbal constructions is essentially an "approximate knowledge of the valence of the verb used." As for the interference of the standard ivorian french, it gradually decreases to the License (Licence 3) before presenting a significant drop in Master (Master 1). The analysis of oral sub-corpus then highlights typical verbal constructions of standard ivorian french. We conclude that students in senior years handle better the standard french and the change in general, than those of early years. We therefore propose a didactics of french in Côte d’Ivoire laying the educational foundation of the change in french in Côte d’Ivoire while emphasizing the importance of a grammatical standard for the entire french-speaking world.

xxiii, 507 p. / This dissertation contextualizes melodic variation within a cultural, historical, and cognitive framework. This work discusses how traditional musicians learn how to vary melodies by observing norms of social and musical behavior exhibited by senior musicians. The core of this dissertation is the transcription and analysis of fifty source recordings of fifty different Irish musicians playing one tune each dating from between 1904 and 2007. Though the transcriptions of the recordings exhibited a high instance of melodic variation (48.2% of the measures), only a small percentage of variation fell on set accented tones (an average of 7.3%). The considerable invariance of set accented tones suggests that part of what constitutes the concept of a tune in an Irish musician's mind relates to the pitch of these key tones. I introduce the term aesthetic conservatism to designate a philosophical approach to performance practice that seeks to maintain both the dance genre and tune identity. I argue that aesthetic conservatism may be a by-product of archetypes and exemplars created through transcriptions and recording technology. This conservatism may also be a function of famine-induced fear of cultural dissolution or inferiority with respect to more prominent music-making supercultures. I call on the philosophy of aesthetic conservatism to explain why few set accented tones are varied. Of the measures that were varied, 74% of those variations involved the addition, subtraction, or redistribution of ornamentation. To catalogue the variety of variations within this sample, I propose a taxonomy that is designed to account for the number of notes in a measure and to assess intervallic differences over successive repetitions of a tune. Finally, I propose a theory to explain the cognitive processes that allow a musician to vary a melody. I suggest that in the mind of a traditional musician there is both a tune schema and a variation schema. These are flexible models that are distinct and separate but that interact within a short span of time because of the exceptionally efficient anatomy of a musician's brain. / Committee in charge: Anne Dhu McLucas, Chairperson; Lori Kruckenberg, Member; Stephen Rodgers, Member; Glen Waddell, Outside Member

MAIA, José Robson. Estudo do L-histidinato de níquel (II) monohidratado sob condições extremas de temperatura e pressão por Espectroscopia Raman. 2014. 106 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2014. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-04-09T20:15:54Z No. of bitstreams: 1 2014_tese_jrmaia.pdf: 4019401 bytes, checksum: 420b482ed2b28ebe5d6b391e56123ee8 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-04-10T20:51:27Z (GMT) No. of bitstreams: 1 2014_tese_jrmaia.pdf: 4019401 bytes, checksum: 420b482ed2b28ebe5d6b391e56123ee8 (MD5) / Made available in DSpace on 2015-04-10T20:51:27Z (GMT). No. of bitstreams: 1 2014_tese_jrmaia.pdf: 4019401 bytes, checksum: 420b482ed2b28ebe5d6b391e56123ee8 (MD5) Previous issue date: 2014 / In this work bis(L-histidinato)nikel(II) Monohydrate crystals were obtained by slow evaporation method using 1 mol of NiCl2.6H2O, 2 mols of L-histidine and NaOH. Reitveld refinement of X-ray data confirmed the structure. Raman modes obtained at ambient conditions of pressure and temperature were assigned by comparison with results on similar materials and by density functional theory DFT calculations. PED (potential energy distribution) is also present. Raman spectroscopy measurements were performed from room temperature up to 150 oC in the 50- 3500 cm-1 spectral range. For temperatures higher than 125 oC the modes related with the water stretching disappeared as well as the lattice modes disappeared indicating a phase transition undergone by the crystal. DSC experiments support this assumption. By decreasing temperature up to 18 K in the 40-3500 cm-1 spectral range it was observed modifications only in internal modes, so we believe that some conformational change has been occurred in the molecules of bis(L-histidinate)nikel(II) Monohydrate. High pressure experiments were performed from ambient pressure up to 9,5 GPa in the 50-3500 cm-1 spectral range. Disappearance of modes between 0,4 and 0,8 GPa was interpreted as evidences of a structural phase transition undergone by the crystal. A second set of modifications in the spectra indicates other phase transition experienced by the crystal between 2,6 and 3,2 GPa. The spectrum obtained the realizing pressure points out to the irreverbility of the phase transitions. / Neste trabalho cristais de L-histidinato de níquel (II) monohidratado (Ni(C6H8N3O2)2.H2O) foram obtidos por meio da evaporação lenta do solvente de uma solução saturada de 1 mol de NiCl2.6H2O, 2 mols de L-histidina mais NaOH. Após a obtenção da amostra a confirmação da estrutura deu-se por refinamento do Reitveld. A classificação dos modos vibracionais à temperatura e pressão ambiente foi realizada por comparação com outros materiais e através de cálculos de teoria da densidade do funcional DFT. A distribuição da energia potencial (PED) também foi calculada. Experimentos de espectroscopia Raman variando a temperatura desde a temperatura ambiente até 150 0C, foram realizadas no cristal de L-histidinato de níquel (II) monohidratado no intervalo espectral entre 50 e 3500 cm-1. Para temperaturas superiores a 125 0C o desaparecimento e surgimento de modos na região dos modos da rede bem como na região dos modos internos indicam uma transição de fase estrutural no L-histidinato de níquel (II) monohidratado devido à saída de água. A transição é irreversível pois o espectro obtido após a amostra retornar a temperatura ambiente é bem diferente daquele obtido no início do experimento. Experimentos de DSC corroboram com o experimento de espectroscopia Raman pois indicam a saída da molécula de água do cristal de L-histidinato de níquel (II) monohidratado no valor de temperatura de 140 0C, e ainda perda de massa de água na mesma temperatura (140 0C), relatada pela curva de TG. Nos experimentos de espectroscopia Raman a baixas temperaturas a amostra de L-histidinato de níquel (II) monohidratado foi resfriada desde a temperatura ambiente até 18 K no intervalo espectral de 40 a 3500 cm-1. Observou-se o surgimento de alguns modos internos, porém, como não evidenciou-se mudanças nos modos externos supomos que o material deva sofrer apenas uma mudança conformacional. Os experimentos de espectroscopia Raman a altas pressões foram realizados no intervalo de pressão entre 0,1 e 9,5 GPa, em um intervalo espectral de 50 a 3500 cm-1. Com o aumento da pressão percebe-se o desaparecimento de modos indicando uma transição de fase estrutural entre 0,4 e 0,8 GPa. Aumentando-se ainda mais a pressão observa-se o surgimento de três modos em torno da frequência de 50 cm-1 no intervalo de pressão entre 2,6 e 3,2 GPa. Estas mudanças indicam uma segunda transição de fase estrutural da amostra de L-histidinato de níquel (II) monohidratado. O espectro obtido após a descompressão é idêntico aquele do início do experimento indicando reversibilidade da transição.

La littérature scientifique dédiée à l’accentuation en anglais australien standard contemporain (SAusE) est, contrairement à celle qui concerne la prononciation de ses voyelles, peu étendue. Après un chapitre introductif proposant le contexte historique dans lequel le SAusE est né et a été décrit, sa définition actuelle ainsi que sa description phonologique, notre étude est consacrée à un examen systémique de l’accentuation lexicale en SAusE. Un corpus test a été mis en place spécifiquement, qui comporte la quasi-totalité des verbes dissyllabiques, des préfixés pluricatégoriels et des exceptions aux règles d’accentuation des mots de deux syllabes et plus, ainsi qu’un large échantillon d’emprunts aux langues aborigènes. Ces quelques 3500 items ont été choisis précisément parce qu’ils font partie des mots les plus susceptibles de connaître une variation accentuelle en anglais contemporain. Notre approche se situe dans la lignée de Lionel Guierre et propose un traitement dictionnairique dans lequel les éléments du corpus sont tous étudiés au travers des données de chacune des éditions les plus récentes des Longman Pronouncing Dictionary, Cambridge English Pronunciation Dictionary et Macquarie Dictionary qui constituent les dictionnaires de références dans le domaine de la prononciation de l’anglais. Ces données ont été complétées, lorsque cela était nécessaire, par des données fréquentielles issues du Corpus of Contemporary American English et par des données orales enregistrées spécialement pour cette étude, selon une démarche similaire à la première partie du protocole du projet Phonologie de l’Anglais Contemporain. Notre analyse met en évidence une grande stabilité accentuelle intervariétale entre le SAusE, l’anglais britannique standard et l’anglais américain standard et propose un relevé étayé et détaillé des spécificités accentuelles lexicales du SAusE contenues dans le corpus étudié. / The scientific literature dedicated to word stress in contemporary standard Australian English (SAusE) is not very extensive contrary to the one dealing with the pronunciation of vowels in this variety of English. We will introduce the historical context in which SAusE first emerged and was described, its current definition as well as its phonological description. Our study is then devoted to the systemic study of lexical word stress in SAusE. A corpus was specifically put together for this particular research : it includes most of the dissyllabic verbs, of the prefixed multicategorial words and of the words that are exceptions to the rules of word-stress assignment in English, as well as a large sample of borrowings from Aboriginal languages. These 3500 items were not chosen randomly : they are words which specifically tend to show word-stress variation in contemporary English. Our approach follows Lionel Guierre’s and offers a dictionary treatment in which all the elements of our corpus are studied using the data of each of the most recent editions of the Longman Pronouncing Dictionary, the Cambridge English Pronunciation Dictionary and the Macquarie Dictionary, all reference books on English pronunciation. Frequency data extracted from the Corpus of Contemporary American English and oral data recorded for this study (following a protocol similar to that which is applied in the first part of the project Phonologie de l’Anglais Contemporain) were added to the dictionary data when necessary. Our analysis brings to the fore a great accentual intervarietal stability between SAusE, standard British English and standard American English, and offers a detailed and complete list of the lexical accentual specificities of SAusE ascertained through our study.

Notre étude s’intéresse à un aspect phonologique : le comportement du phonème /R/ du français parlé à Niamey, capitale du Niger, pays de l’Afrique subsaharienne. L’enquête a été mené selon le protocole du projet international, Phonologie du Français Contemporain (abrégé PFC). Il vise à rassembler un vaste corpus oral de français contemporain à travers toutes les zones francophones du monde.Nos enquêtes de terrain ont été effectuées dans une ville où le français demeure la langue officielle, et où l’on retrouve aussi d’autres langues nationales et/ou locales (haousa, songhaï-zarma, touareg, peul, kanuri et arabes). Une présentation des rhotiques du point de vue phonétique et phonologique s’est avéré nécessaire, avant la classification et l’analyse de nos données. D’une part nous avons analysé les allophones de /R/ réalisés par les enquêtés. Ces analyses montrent que la réalisation largement majoritaire est la vibrante alvéolaire [r], suivie de loin par la fricative uvulaire [ʁ], puis par les réalisations [ɰ], [χ], [ɻ] et la non-réalisation de /R/ [ø]. Tous ces résultats ont été comparés ensuite à ceux d’autres points d’enquêtes PFC dans le monde. D’autre part, nous nous sommes intéressés à la chute de /R/ dans les groupes consonantiques et en finales, pour aboutir à la conclusion que ce phénomène dépend du lexique et, plus exactement, concerne généralement la prononciation des chiffres (par exemple quatre [katR]> [kat]). / This thesis focuses on the phonological aspect of the /R/ in French language spoken in Niamey, the capital of Niger, a Sub-Saharan country of Africa. The survey has been conducted conforms to theprotocol and the mehology of an international project Phonologie du Français Contemporain (PFC), which aims to collect a large corpus of contemporary French spoken from all around the word. In Niamey, French coexists with others national and local languages: haousa, songhaï-zarma, touareg, peul, kanuri et arabic.In the proposed work at first we have illustrated a phonetic and phonology classification of rhotics class, then we have classified and analyzed our data. We have analyzed all allophones of /R/ produced by the interviewed speakers. These data show that the largest part of the speaker pronounce a vibrant alveolar [r], followed by a fricative uvular [ʁ], and then by [ɰ], [χ], [ɻ] and [ø]. Furthermore, we have compared our results with other PFC studies conducted all around the francophone word. Additionally, we have focused on fall of /R/ in cluster group, and we concluded that this fall depends on the lexicon, and concerns especially numbers pronunciation (for example, quatre [katR]> [kat]).

Notre modèle d'étude, Mycoplasma mycoides subsp. mycoides (Mmm), est l'agent de la péripneumonie contagieuse bovine (PPCB). Cette maladie fut un des plus grands fléaux de l'élevage bovin au XIXème siècle et sévit encore largement en Afrique. A cause de son impact sur l'économie, elle a bénéficié de grandes attentions dans les pays industrialisés, notamment lors des épisodes de résurgence européens dans les années 1980-90. Inscrite sur les listes de l'OIE, la PPCB est à déclaration obligatoire, ce qui entraine de sévères mesures de restriction sur le commerce des animaux vivants. Plusieurs espèces de mycoplasmes sont phylogénétiquement proches de Mmm. Pour mieux comprendre la pathogénie de cette maladie, il est nécessaire d'analyser les facteurs qui peuvent concourir à la virulence de l'agent pathogène incriminé. Dans ce contexte, nous nous sommes intéressés aux exopolysaccharides (EPS) de Mmm, candidats clés dans la virulence de cette bactérie. Ils ont été caractérisés chimiquement par HPLC et RMN, puis comparés aux polysaccharides capsulaires (CPS) dans le cadre d'une étude sur des variants intraclonaux de Mmm. Ces expériences ont été rendues possibles grâce à l'élaboration d'un protocole offrant une production optimale des EPS pour les analyses et un affranchissement des contaminants du milieu lors de leur isolement à partir des surnageants de culture. Ce protocole a permis, par ailleurs, d'élargir l'étude de caractérisation chimique des EPS au groupe « mycoides » auquel appartient Mmm. La production d'anticorps monoclonaux anti-polysaccharides a offert la possibilité d'étudier les communautés antigéniques au sein du groupe et de caractériser la localisation du polymère sécrété (CPS et/ou EPS). Les génomes séquencés et annotés disponibles ont fait l'objet d'études in silico sur les voies de biosynthèse potentiellement impliquées dans la production des polysaccharides. Les résultats montrent que dans le cas de Mmm, les variants d'un même clone présentent des différences de production de polysaccharides se traduisant par un phénotype opaque/translucide en culture sur milieu solide pouvant être associé à un « switch ON/OFF » du gène qui code un transporteur de glucose. Mmm sécréte du galactane (polymère de β-D-(1-6) galactofuranose) identique au composé associé à la membrane. Au sein du groupe « mycoides », deux espèces sécrètent un β-D-(1-2) glucane dont la structure linéaire est originale. L'analyse des voies de biosynthèse des génomes concernés concorde avec les deux produits mis en évidence. De nombreux gènes impliqués semblent résulter de transferts latéraux venant de mycoplasmes éloignés phylogénétiquement mais qui partagent le même habitat / Our model, Mycoplasma mycoides subsp. mycoides (Mmm), is the agent of contagious bovine pleuropneumonia (CBPP). CBPP is a severe contagious disease currently present in Africa. CBPP is classed as a notifiable disease by the OIE, which implies severe restrictive measures in in the trade of live animals. Because of its economic importance, CBPP has received much attention in indusdrialized country, notabily when the disease had reemerged in Europe in 1980’s and 90’s. To better understand the pathogenesis of this disease, it is necessary to analyze the factors that may contribute to the virulence of this agent. In this context, we were interested in Mmm exopolysaccharides (EPS), potential key molecules in the virulence of this bacterium. First, Mmm EPS were chemically characterized by HPLC and NMR and compared to the capsular polysaccharides (CPS) in a study on intraclonal Mmm variants. To conduct these experiments, a suitable methodology was developed to produce and to purify EPS from culture supernatants by avoiding technical difficulties due to the complexity of the mycoplasma growth medium. Then, this protocol allowed extending the study to the chemical characterization of EPS from mycoplasmas belonging to the Mycoplasma mycoides cluster (MMC) as Mmm. The production of monoclonal antibodies recognizing Mmm and Mccp polysaccharides was used to study the antigenic communities within this group of mycoplasmas and to characterize the location of the secreted polymer (CPS and/or EPS). The sequenced and annotated genomes were used to manage in silico studies of biosynthetic pathways potentially involved in the production of polysaccharides. The results showed that Mmm intraclonal variants resulting in an opaque / translucent phenotype on solid culture may be associated with an “ON/OFF switch" of the gene encoding a glucose transporter and, in turn associated to the production of either CPS or EPS. Mmm secretes a β-(1-6) galactofuranose polymer identical to that of the membrane associated compound, excepted it has no lipid anchor. Within MMC, there are two species that secrete a β -(1-2) glucan, the linear structure of which is original. The analyses of the biosynthetic pathways of the different genomes were consistent with the structure of the related secreted products. Many genes could appear to originate from phylogenetically distant mycoplasmas that share the same habitat