La nourriture traditionnelle compose une part essentielle de la culture Inuit. Néanmoins, la contamination de cette nourriture par les organochlorés et les métaux lourds fait l’objet d’une attention toute particulière, car elle excède dans certains cas les recommandations canadiennes. Le but de ce travail est, d’une part de mettre à jour les estimés d’exposition au chlordane, au BPC, au toxaphène et au mercure, et d’autre part d’en explorer certaines sources de variation. Pour ce faire, de nouvelles données sur la concentration de ces contaminants parmi les plus importants aliments traditionnels ont été combinées aux relevés alimentaires assemblés dans l’Arctique canadien en 1998 et 1999, la quantité et le type de nourriture traditionnelle consommés étant supposés ne pas avoir changé. D’après l’ensemble des nouveaux estimés obtenus, les changements dans la banque de données sur les contaminants affectent plus les extrémités des distributions que les mesures de tendance centrale. Les estimés d’apports en organochlorés peuvent être considérés comme toujours actuels étant donné que les cinq types d’aliments pour lesquels il y a des nouvelles données disponibles représentent la majorité de l’exposition totale. En ce qui concerne le mercure, toutefois, des données additionnelles sont nécessaires à propos du caribou, du narval, du muktuk du béluga et de la truite de lac pour générer des niveaux d’exposition plus exacts. Les sources de variations de ces estimés d’exposition ont été explorées en évaluant les coefficients de variation propres aux apports alimentaires et ceux propres aux concentrations de contaminants dans les aliments traditionnels. Il s’avère que la variation attribuable aux méthodes de collecte de données alimentaires est plus élevée que celle attribuable à la mesure des contaminants dans les banques de données. De nouvelles méthodes pour mesurer les niveaux de consommation d’aliments traditionnels devraient être développées. / Traditional food is a part of Inuit culture. Nevertheless, contamination of this food by organochlorines and heavy metals is the subject of constant attention since it’s exceeding Canadians guidelines in some cases. The purpose of this work is to do an update of the exposure estimates for chlordane, PCB, toxaphene and mercury and to explore sources of variation. To do so, new data on concentration of contaminants in traditional food have been combined to dietary recalls collected in the Canadian arctic in 1998 and 1999 assuming that the quantity and the type of traditional food consumed didn’t change. According to the new estimates, changes in the contaminant database affected more the extremes of the distributions rather than the measures of central tendency. The estimates of organochlorines intakes can be considered updated since the five types of food for which data are available represent the majority of total exposure. For mercury, additional data are necessary for caribou, narwhal, beluga muktuk and lake trout to generate more exact estimates of exposure. The sources of variation of the exposure estimates have been explored by evaluating the coefficients of variation related to the measure of the dietary intake and those related to the contaminant concentrations in traditional food. The variation attributable to the methods of collecting food intake data is higher than the variability attributable to the contaminant database. New methods to measure the levels of traditional food consumption should be developed.

This research focuses on developing sensors for properties of aerodynamic interest (i.e., flow and pressure) based on low-cost polymeric materials and simple fabrication processes. Such sensors can be fabricated in large arrays, covering the surface of airfoils typically used in unmanned vehicles, allowing for the detection of flow separation. This in turn potentially enables, through the use of closed-loop control, an expansion of the flight envelope of these vehicles. A key advance is compensation for the typically inferior performance of these low cost materials through both careful design as well as new readout methods that reduce drift, namely a readout methodology based on aeroelastic flutter. An all-polymer micromachined piezoresistive flow sensor is fabricated, based on a flexible polyimide substrate and an elastomeric piezoresistive composite material. The flow sensor comprises a cantilever that is extended into the embedding flow; flow-induced stress on the cantilever is sensed through the piezoresistive composite material. Increasing the sensitivity of the sensor is achieved by either utilizing a long single-cantilever beam or using a dual-cantilever beam supporting a flap extending into the flow. In the latter case, the sensor demonstrates increased sensitivity with a reduced cantilever length. The increase in sensitivity helps to reduce sensor drift, which in turn is further reduced by a new measurement method, the vibration amplitude measurement method. In this drift reduction measurement method, the flow-induced vibration amplitude of the sensor structure (i.e., the amplitude of the aeroelastic flutter induced by the flow), instead of the absolute value of cantilever deflection, is measured in order to find the flow rate. Measurement of this relative resistance change instead of the absolute resistance in the piezoresistor rejects common-mode drift and greatly reduces overall drift. Experimental results verify the expected drift reduction. Sensor drift is also reduced when the elastomeric piezoresistive material is replaced by a Pt thin film piezoresistor. Development of pressure sensors based on polymers proceeds by encapsulating a reference cavity within a multilayer polymer structure and forming capacitor plates on the polymeric membranes encapsulating the cavity. Measuring the capacitance change induced by changes in the embedding pressure (which cause changes in the positions of the bounding polymeric membranes) enables calculation of the pressure. The use of polymeric membranes requires understanding the leakage rate of gas into the reference cavity, which is a source of pressure drift. Developing a polymer-based pressure sensor that solves the problem of sensor drift as a result of gas permeation entails the fabrication of a silicon pressure reference cavity embedded in the polymer substrate, which results in a more hermetic and lower drift sensor while preserving the flexibility of the embedding polymer. Both wired and wireless versions of pressure and flow sensors of these types were developed and characterized. Further, the sensors were characterized on airfoils and their performance in a wind tunnel was determined.

If sufficiently persistent, semi-volatile organic contaminants (SVOCs) can travel long distances through the atmosphere from their points of release and become concentrated in cold, remote regions. As air is sampled for SVOCs to establish both their presence and the success of emission reduction efforts, it becomes helpful to determine sampling site proximity to sources and the origin of the sampled air masses. Comparing three increasingly sophisticated methods for quantifying source proximity of sampling locations, it was judged necessary to account for the actual history of the sampled air through construction of an airshed, especially if wind is highly directional and population distribution is very non-uniform. The airshed concept was improved upon by introducing a ‘geodesic’ grid of equally spaced cells, rather than a simple latitude/longitude grid, to avoid distortion near Earth’s poles and to allow for the comparison of airshed shapes. Assuming that a perfectly round airshed reveals no information about sources allows the significance of each cell of an airshed to be judged based on its departure from roundness. Combining air-mass histories with a 2 year-long series of SVOC air concentrations at Little Fox Lake in Canada’s Yukon Territory did not identify distinct source regions for most analytes, although γ-hexachlorocyclohexane appears to originate broadly in north-eastern Russia and/or Alaska. Based on this remoteness from sources, the site is judged to be well suited to monitor changes in the hemispheric background concentrations of SVOCs. A model-based exploration revealed wet-gaseous deposition as the dominant process responsible for cold-trapping SVOCs in mountain soils. Such cold trapping is particularly effective if precipitation rate increases with altitude and if temperature differences along the mountain are large. Considerable sensitivity of the modeled extent of cold-trapping to parameters as diverse as scale, mean temperature, atmospheric particle concentration and time relative to emission maxima is consistent with the wide variety of observed enrichment behaviour. Concentration gradients of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in air and soil measured on four Western Canadian mountains with variable distance from sources revealed source proximity as the main driver of concentrations at both the whole-mountain scale and along individual mountain transects.

If sufficiently persistent, semi-volatile organic contaminants (SVOCs) can travel long distances through the atmosphere from their points of release and become concentrated in cold, remote regions. As air is sampled for SVOCs to establish both their presence and the success of emission reduction efforts, it becomes helpful to determine sampling site proximity to sources and the origin of the sampled air masses. Comparing three increasingly sophisticated methods for quantifying source proximity of sampling locations, it was judged necessary to account for the actual history of the sampled air through construction of an airshed, especially if wind is highly directional and population distribution is very non-uniform. The airshed concept was improved upon by introducing a ‘geodesic’ grid of equally spaced cells, rather than a simple latitude/longitude grid, to avoid distortion near Earth’s poles and to allow for the comparison of airshed shapes. Assuming that a perfectly round airshed reveals no information about sources allows the significance of each cell of an airshed to be judged based on its departure from roundness. Combining air-mass histories with a 2 year-long series of SVOC air concentrations at Little Fox Lake in Canada’s Yukon Territory did not identify distinct source regions for most analytes, although γ-hexachlorocyclohexane appears to originate broadly in north-eastern Russia and/or Alaska. Based on this remoteness from sources, the site is judged to be well suited to monitor changes in the hemispheric background concentrations of SVOCs. A model-based exploration revealed wet-gaseous deposition as the dominant process responsible for cold-trapping SVOCs in mountain soils. Such cold trapping is particularly effective if precipitation rate increases with altitude and if temperature differences along the mountain are large. Considerable sensitivity of the modeled extent of cold-trapping to parameters as diverse as scale, mean temperature, atmospheric particle concentration and time relative to emission maxima is consistent with the wide variety of observed enrichment behaviour. Concentration gradients of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in air and soil measured on four Western Canadian mountains with variable distance from sources revealed source proximity as the main driver of concentrations at both the whole-mountain scale and along individual mountain transects.

Les sources d’émissions de polluants organiques persistants (POP) dans l’atmosphère sont relativement bien connues. Une fois dans ce compartiment sous formes gazeuse et/ou particulaire, ces composés sont transportés à plus ou moins longue distance puis éliminés en fonction des conditions météorologiques par dépôts secs (aérosols) ou humides (pluie et neige). L’impact des POP est planétaire, tous les milieux de l’environnement sont touchés et les milieux aquatiques de montagne ne sont pas épargnés. Plusieurs études ont rapportées la présence de Polychlorobiphényles (PCB) et d’Hydrocarbures Aromatiques Polycycliques (HAP) sur des lacs d’altitude européens où l’atmosphère est l’unique source de pollution. A ce jour, très peu d’études ont été menées en milieux de montagne pour comprendre et identifier les mécanismes de transfert à l’interface entre l’air et l’eau. Ces travaux de thèse sont ainsi focalisés sur les échanges de POP à l’interface air-eau en milieu aquatique de montagne. Dans le but de définir le rôle de l’atmosphère sur ces milieux et de calculer des flux de POP, deux systèmes hydriques distincts ont été étudiés : un lac d’altitude (Lac de la Muzelle, Oisans) et une rivière alpine (Arc, vallée de la Maurienne). Deux familles de POP ont été ciblées pour leurs différentes propriétés physico-chimiques : les HAP et les PCB. Pour l’étude de ces milieux de montagne parfois difficile d’accès, une stratégie d’échantillonnage passive a été choisie. Les systèmes d’échantillonnage employé ont été améliorés, développés au laboratoire ou utilisés tel quel pour échantillonner distinctement toutes les formes de POP dans l’air (gaz, particules, dépôts secs et humides) et dans l’eau (phase dissoute et particulaire). Une comparaison des systèmes d’échantillonneurs atmosphériques passifs a été réalisée pour définir le plus fiable et représentatif. Ces études de transferts air-eau ont été conduites sur le lac d’altitude pendant deux périodes estivales (2014 et 2015) et un suivi de deux ans a été réalisé (2014 à 2016) sur la rivière alpine.Le rôle de l’atmosphère en période estivale a pu être ainsi défini sur le lac d’altitude et des flux d’échanges de polluants à l’interface ont pu être calculés. La rivière alpine étant un système hydrique dynamique plus complexe pour l’étude des transferts air-eau et la quantification de flux, un suivi spatio-temporel de la contamination a tout d’abord été réalisé le long de la rivière et une première approche de calcul de flux de polluants à l’interface a été appliquée. / Atmospheric sources of persistent organic pollutants (POPs) are relatively well known. Once in this compartment under both gas and particulate forms, these compounds are carried on more or less long range. Then, pollutants are eliminated by dry (aerosol) or wet (rain, snow) depositions according to meteorological conditions. The global planetary distribution of POPs affects all environments and mountain aquatic environments are not spared. Several studies on European high altitude mountain lakes have reported the presence of Polychlorinated Biphenyls (PCBs) and Polycyclic Aromatic Hydrocarbons (PAHs). In these remote areas, the atmospheric compartment is the unique source of pollution. Few studies were conducted in order to understand and identify transfer mechanisms at the air-water interface in mountain. So, this thesis focused on POP exchanges at the air-water interface. In order to characterize atmospheric influence on aquatic compartment and calculate pollutant fluxes, two separate water systems were studied: a high altitude lake (Muzelle lake, Oisans) and an alpine river (Arc, Maurienne valley). Two POP families were targeted for their different physicochemical properties: PAHs and PCBs.In these mountain environments with limited access and energy, passive sampling strategy was chosen. Samplers were improved, developed in the lab or used to distinctly collect all POP forms in the air (gas, particulate, dry and wet depositions) and water (dissolved, particulate). A comparison of different atmospheric passive samplers was conducted to define the most reliable and representative. The air-water transfer studies were realized on the high altitude lake over two summer periods (2014 and 2015) and over a two years monitoring (2014 to 2016) in the alpine river. So, the atmospheric role on the alpine lake in summer was defined and air-water flux exchanges were calculated. As the alpine river is a more complex water system for the air-water transfers study and quantification, in a first time a space-time contamination monitoring was conducted along the river and a first approach was applied to calculate pollutant fluxes at the interface.

Dans ce travail de thèse, nous avons évalué les effets neurotoxiques multigénérationnels de l’exposition des mères F0 gestantes et allaitantes aux polychlorobiphényles non-dioxin-like indicateurs (PCB-NDLi), à un profil mimant l'exposition humaine à partir de poissons contaminés, sur le développement et le comportement, y compris les réponses émotionnelles et les interactions sociales, des deux générations F1 et F2 des souris mâles et femelles, à différentes phases de leur ontogenèse. Deux faibles doses des PCB-NDLi : (i) la DJT, qui est de 10 ng/kg/j, et (ii) une dose environnementale de 1000 ng/kg/j, ont été administrés par accès libre aux souris mères F0. En fonction de la modalité d’exposition des parents F1 aux PCB, 4 groupes de génération F2 ont été obtenus, en croisant (i) des pères F1 exposés à des mères F1 non exposées, (ii) des mères F1 exposées à des pères F1 non exposés, (iii) des deux parents F1 exposés, ou (iv) des deux parents F1 non exposés (témoins), aux PCB en période périnatale. Nos résultats ont montré que les mâles adultes de la génération F1 ont manifesté un comportement dépressif-like ; alors que les mâles F2, issus uniquement des pères F1 exposés aux PCB, ont exhibé un comportement anti-dépressif-like, ce que suggère que l’exposition périnatale des souris F1 aux PCB-NDLi a induit une altération multigénérationnelle d’origine parentale du comportement de la résignation, et ce d’une façon sexe dépendante. De même, une altération sexe-dépendante de l’anxiété, a été détectée chez la génération F1 exposées durant la période périnatale aux PCB-NDLi comme uniquement les souris mâles d’âge moyen F1 ont développé un phénotype anxieux qui a été transmis aux souris mâles d’âge moyen F2, via leurs pères F1. En outre, une altération multigénérationnelle du comportement social a été détectée chez les souris mâles et femelles F1 et F2. D’une façon remarquable, chez la génération F2, des altérations comportementales dépendantes à la fois du sexe et de la dose, ont été trouvées, malgré l’absence d’effets chez leurs parents F1, effets qui dépendaient également de l’origine parentale, tels que la diminution significative du niveau de la préférence pour la nouveauté sociale chez les souris mâles F2, issues uniquement des mères F1 périnatallement exposées à la dose 10 ng/kg de PCB. Le dosage des biomarqueurs chez les souris d’âge moyen de la génération F1 a révélé une altération de nombreux paramètres biochimiques, y compris une augmentation du niveau de corticostérone et de l’activité de l’acétylcholinestérase / In this study, we evaluated the multigenerational neurotoxic effects of gestational and lactational exposure of F0 female mice to a representative mixture of the six indicator non-dioxin-like-polychlorinated biphenyls (NDL-PCBs) at environmentally low doses, a profile that closely mimics human exposure to contaminated fish. The tolerable day intake (TDI) of 10 ng/kg/day and a higher environmental dose of 1000 ng/kg/day were administered by free access to F0 mothers during pregnancy and lactation. Afterwards, the development and behavior, including emotional responses and social interactions, of the two F1 and F2 generations of Swiss male and female mice at different phases of their ontogenesis, were assessed. Depending on the mode of exposure of F1 parents to PCBs, four F2 generation groups were obtained by crossing (i) F1 fathers perinatally exposed with unexposed F1 mothers, (ii) F1 mothers perinatally exposed with unexposed F1 fathers, (iii) both F1 parents perinatally exposed, or (iv) both F1 parents perinatally unexposed (controls), to PCBs. Our results showed that F1 adult males showed depressive-like behavior whereas F2 adult males, coming from F1 mothers, perinatally exposed to PCBs, exhibited anti-depressive-like behavior. This result suggested an induction of a multigenerational alteration that was of parental origin, on the resignation behavior in a sex-dependent manner. Similarly, sex-selective anxious behavior was detected in F1 middle-aged males perinatally exposed to PCBs, which was transmissible to F2 middle-aged males, via their F1 fathers. Furthermore, a multigenerational alteration of social behavior was found in F1 and F2 male and female mice. Remarkably, some behavioral alterations in F2 generation were found, despite of the absence of effects in their F1 parents, such as a significant decrease in the level of preference for social novelty in F2 male mice, coming from F1 mothers perinataly exposed to 10 ng/kg of NDL-PCBs. The biomarker assays in F1 middle-aged mice revealed an alteration in many biochemical markers, including increased corticosterone levels and acetylcholinesterase activity in male as well as females.

A presente pesquisa trata das relações entre escritores e Partido Comunista do Brasil (PCB) na cidade de Porto Alegre. O objetivo é revelar e explorar as articulações entre o mundo da militância comunista e o mundo da literatura porto-alegrense entre as décadas de 1920 e 1960 a partir da trajetória dos homens e das mulheres produtores de literatura que aderiram ao Partido, entre eles: Beatriz Bandeira, Cyro Martins, Dyonélio Machado, Edith Hervé, Fernando Melo, Ivan Pedro de Martins, Jorge Bahlis, Laci Osório, Lila Ripoll e Plínio Cabral. Para tanto, utiliza um conjunto de fontes composto por compêndios bibliográficos, documentos oficiais do PCB, entrevistas, memórias, textos literários, periódicos, relatórios provenientes da polícia e Anais da Assembleia Legislativa do Rio Grande do Sul. Tais testemunhos são tomados como canais de acesso a situações em que os escritores lançaram mão de diferentes recursos em prol do Partido e a episódios elucidativos da repercussão da militância de esquerda em suas vidas e em suas carreiras. Dividida em seis capítulos, a tese busca mostrar, enfim, em que medida o arranjo social em que os escritores atuaram em diferentes contextos políticos gerou condições para que universos pretensamente independentes fossem perpassados por regras alheias. / This thesis concerns about the connections with some writers and the Brazil's Communist Party (PCB) in Porto Alegre. Our aims here are to reveal them and further to exploit the link between the communist activity and the literary world in Porto Alegre since 1920 to 1960 taking as a point of departure the trajectory of men and women writers engaged to the communist party. Among them, we particularly mention here Beatriz Bandeira, Cyro Martins, Dyonélio Machado, Edith Hervé, Fernando Melo, Ivan Pedro de Martins, Jorge Bahlis, Laci Osório, Lila Ripoll and Plínio Cabral. In order to reach our aim we use a set of sources composed of bibliographic compilation, PCB's official documents, interviews, memoirs, literary texts, news papers, magazines, police’s accounts and the Legislative Assembly of Rio Grande do Sul's Annals. All these testimonies are taken as access channels to specific contexts wherein these writers used different resources to aid the party's causes and to light up some episodes of the impact of leftist activity in their own lives and literary work. Our research is divided into six parts to show how the social arrangement where these writers acted in different political contexts gave birth to the conditions to supposedly independents universes were pervaded by others rules.

A presente dissertação tem como objetivo fundamental o estudo da relação do PCB e do PCdoB com o MDB-PMDB no processo de distensão política da ditadura militar. Entre as questões estudadas destacam-se o processo de aproximação das agremiações comunistas ao MDB, enfatizando que este processo era reflexo dos limites impostos pelo regime autoritário, dando origem à dupla militância, por parte dos comunistas: legal (MDB-PMDB) e ilegal (PCB e PCdoB). Examinam-se as eleições no RS desde a instauração do bipartidarismo, com especial ênfase às eleições de 1982, que foi a última eleição em que essas três agremiações funcionaram como uma "unidade" partidária. Para tanto, analisa-se a linha tático-estratégica dos comunistas em consonância com o PMDB e as suas aspirações com respeito ao fim do regime, assim como o próprio cotidiano da vida partidária e os reflexos advindos desta dupla militância na dinâmica infrapartidária. Trata-se de um trabalho de reconstituição histórica em que, além das fontes bibliográficas e dos resultados eleitorais, faz-se uso da documentação partidária do período e de entrevistas com militantes partidários sobre as eleições de 1982. / This dissertation aims to study the fundamental relationship between the PCB and the PCdoB with the MDB-PMDB distension in the policy of the military dictatorship. Among the issues examined included the process of approximation of the MDB communist associations, emphasizing that this process was reflective of the limits imposed by the authoritarian regime, leading to double militancy on the part of communists: legal (MDB-PMDB) and illegal (PCB and PCdoB). It examines the elections in RS since to begin the bipartisan system, with special emphasis for election of 1982, which was the last election in that the three associations functioned as a "unity" party. Thus, it examines the strategic-tactical line of the communists in line with the PMDB and aspirations with respect to the end of the procedure, so as the daily life of the party and reflexes arising in the dynamics of double militancy into partisan. This paper is about a historical reconstitution where, besides the bibliographical sources and the electoral results, use the partisan documentation of the period and interviews with militant partisans the 1982 elections.

L'intégration des nouveaux éléments basés sur la physique des plasmas dans le domaine des circuits et des systèmes micro-ondes est l'objectif de ce travail. En profitant des caractéristiques électromagnétiques des plasmas et en jouant sur leur architecture, on développe des micro-commutateurs micro-ondes et d'autres circuits radio et hyperfréquences en technologies microrubans ou en guide d'onde… La simulation de la propagation des ondes électromagnétiques dans un plasma et les études de l'interaction entre un plasma et les ondes électromagnétiques nécessite la connaissance des paramètres fondamentaux du plasma comme la permittivité. C'est pour cela qu'on étudie aussi les mesures plasmas par différents techniques comme la transmission/réflexion des ondes électromagnétiques, la perturbation des cavités résonnantes, ... Un schéma électrique équivalent modélisant un micro-commutateur hyperfréquence en plasma, est obtenu grâce aux mesures des courants de décharge électrique, à la rétro-simulation et aux techniques de modélisation numérique. Un coupleur directif hybride compact est utilisé pour les mesures plasmas en assurant la protection du matériel et de l'équipement de mesure des signaux d'un plasma. / Integration of new plasma-based elements for RF and microwave circuits and systems is the goal of this work. Taking advantage of electromagnetic characteristics of plasmas and playing on their architecture, we develop microwave micro-switches and other RF and microwave circuits by different technologies such as microstrip, waveguide circuits. The simulation of the propagation of electromagnetic waves in plasma and studying the interaction between plasma and electromagnetic waves require a pre-knowledge of its basic intrinsic parameters such as permittivity for that we also study measures and plasma different techniques like transmission/reflection of an electromagnetic waves, cavity perturbation technique... An equivalent electrical circuit modeling the plasma will be used for modeling microwave micro-switches. It is obtained by measurements of electric discharge currents, the reverse CAD simulation and numerical modeling techniques. A compact hybrid directional coupler is used to measure plasma and to protect test equipment from dangerous signals of the electrical discharge.

Made available in DSpace on 2014-06-11T19:26:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2000Bitstream added on 2014-06-13T19:13:38Z : No. of bitstreams: 1 pomar_per_me_fran.pdf: 1438282 bytes, checksum: a6265152c06528500f8c16563f9a09c5 (MD5) / O presente trabalho examina conflito de natureza política ocorrido em 1949 em Ribeirão Preto, por ocasião do II Congresso das Câmaras Municipais do Estado de São Paulo (também chamado Congresso das Municipalidades ou Congresso Municipalista). Operação policial resultou em processo criminal contra treze vereadores de onze municípios, seis dos quais chegaram a ser presos. Todos, exceto um, eram militantes do Partido Comunista do Brasil (PCB), eleitos em novembro de 1947 por diferentes legendas: PSD, PTB, UDN, PSP, PSB, PTN. Pretende-se demonstrar que o caso expressa a lógica repressiva liberal-conservadora, anticomunista, antinacionalista vigente no governo Dutra, à qual aderiu o governador de São Paulo, Adhemar de Barros, embora tenha sido eleito para o cargo com apoio decisivo do PCB. Procura-se descrever as atividades dos órgãos de repressão política, neste caso, destacadamente o Departamento de Ordem Política e Social (DOPS-SP); bem como analisar a ação do PCB, em particular em Ribeirão Preto, nas suas características organizativas, ideológicas e políticas. / This work examines politic nature conflict ocurred in 1949 at Ribeirão Preto City, during the São Paulo State Second Congress of City Halls (also called Congress of Municipalities). The police operation resulted in a criminal process against thirteen concillors of eleven cities, six of wich were arrested. All of them, but one, were militants of Communist Party of Brazil (PCB), elected in November 1947 by different legends, including PSD, PTB, UDN, PSP, PSB, PTN. The author wants to demonstrate that this episode express the repressive logic liberal-conservative, anticommunist and antinacionalist valid in Dutra's government, used by São Paulo's governor, Adhemar de Barros, although he has been supported by PCB. The research describes the organ's activities engaged in political repression during the refered period, mainly the Departamento de Ordem Política e Social, DOPS. Also, it analyzes the organization, ideologies and political characteristcs of PCB, particulary in Ribeirão Preto City.