Les milliers de messages publiés quotidiennement sur internet constituent autant d'indices de pratiques, d'attitudes et d'opinions exprimées sur de nombreux sujets, dont la politique. Ces messages peuvent être appréhendés comme un véritable matériau d'analyse du monde social. Ils présentent néanmoins une certaine spécificité par rapport à d'autres types de données : ils ne sont pas générés par et pour un protocole de recherche. De ce fait, le chercheur ignore bien souvent les propriétés sociologiques de leurs auteurs. Afin de pouvoir situer ces auteurs dans le monde social « réel », nous avons construit notre propre dispositif méthodologique de panélisation d'une population d'inscrits au réseau social Twitter. Les données générées par notre dispositif nous ont permis d'observer que, bien que politisés et dotés en capitaux culturels, les individus publiant des messages politiques ne le font que de façon très intermittente. Le niveau de production de messages politiques sur Twitter est en fait corrélé au niveau d'activité du champ de production de l'information et de l'opinion. On peut donc appréhender Twitter comme un observatoire du marché des opinions politiques. / Thousands of texts daily published on the Internet indicate practices, attitudes and opinions on plenty of issues, politics included. They can be considered a real material to analyze the social world. These digital texts are quite specific, with regard to other types of data: they are not generated by and for a research protocol. Therefore, the researcher ignores the sociological properties of their authors. In order to identify these authors in the real social world, I built my own methodological plans to panelize the members of the social network Twitter. The data generated by my method support the following idea : the individuals who publish political texts are politicized and have high cultural capital. Besides, they only do so on an occasional basis. The level of production of political tweets is in fact correlated to the level of activity of the field of production of information and opinion. Twitter can therefore be considered a monitoring tool of the political opinion market.

The politics of Blacks are stereotypically assumed to be the same and share the same race-based root, be it disenfranchisement or solidarity. Given the recent jump in Black political participation and the seemingly race-based and partisan nature "the Black vote" holds, it is essential to investigate what factors drive Black voter turnout as well as what factors contribute to the partisan nature of Black voters. Most other studies of political opinion, turnout, and party preference only consider comparable demographic groups such as men versus women or Blacks versus Whites. This study examines partisan preference and participation only among Black Americans. The data used here come from the American National Election Survey (ANES) 1984, 1996, and 2008 Pre- and Post-Election Survey, election years that coincided with peaks and lows of Black voter turnout since the Civil Rights Movement. Findings indicate that Black Democrats report higher voter turnout than Black non-Democrats, and younger Blacks and those who opposed abortion were less likely to vote. Also, results suggest that although Black partisanship can be predicted by gender, abortion stance, and age, partisanship is largely not a product of demographics or political stances based on how little variance these models account; rather, Black partisanship may be explained by aspects that go beyond these usual determinants, measures, and proxies. Implications of this study show that non-Democratic Blacks were political available to other parties, and it warrants a further investigation into Black partisanship.

Comment les citoyens reçoivent-ils et interprètent-ils les informations politiques auxquelles ils sont exposés quotidiennement ? Cette thèse s’intéresse au contexte d’exposition aux informations et met en évidence la diversité des interprétations dont celles-ci font l’objet. Elle porte une attention aux usages et en explore les implications politiques. Les résultats sont énoncés à partir d’un regard croisé entre une démarche d’analyses quantitative et qualitative. L’approche qualitative met en place un protocole d’enquête original, qui s’appuie sur des entretiens de couple réalisés en France. Les résultats portent sur l’exposition aux informations, l’attention qui leur est accordée et enfin leur interprétation. L’exposition aux informations s’inscrit, pour l’ensemble des citoyens, dans une routine quotidienne et s’imbrique dans leurs emplois du temps familiaux et professionnels. Les citoyens, quel que soit leur niveau de politisation ou leur origine sociale, ne font pas état d’une démarche intentionnelle de recherche d’informations. En conséquence, leur attention est variable car dépendante de ce contexte. Elle est tributaire des intérêts qu’ils déploient vis-à-vis du champ politique et de l’action publique mais aussi des caractéristiques de l’offre médiatique. Quatre processus d’interprétation sont identifiés. Leur diversité s’appuie sur l’existence de convictions politiques ancrées, qui guident l’interprétation, et sur les modalités de combinaison des expériences personnelle et médiatique. La thèse met ainsi en évidence les grilles de lecture que les citoyens mobilisent pour donner sens au monde qui les entoure et témoigne du rôle des informations dans leur construction. / How do citizens receive and interpret political news to which they are daily exposed? This PhD thesis deals with the context in which people are exposed to news and sheds light on the diversity of their interpretation. Emphasis is put on media uses and on the investigation of their political implications. The results are based on a mixed method approach (quantitative and qualitative). The qualitative approach offers an inventive interview protocol with French couples, in Paris region and in the North of France. The results focus on exposure to news, attention to news and interpretation. All citizens are exposed to news in daily routine, within their work and family lives. They do not seek for information, regardless of their level of political interest or their social background. Consequently, their attention to news is variable because it is dependent on this context. Not only is attention reliant on citizens’ interests in the political scene and public action but also on the way the media present and construct news. I identify four types of interpretation. Their diversity relies on deeply rooted political convictions, which guide the interpretation, and on the way personal and media experiences are combined. This PhD thesis also singles out the frameworks of interpretation used by citizens to make sense of the world around them and how information contributes to their construction.

The aim of this thesis is to study political opinions and party voting in relation to class. The range of opinions studied consists of a socioeconomic dimension, dealing with issues of economic equality, and a socio-cultural dimension, dealing with questions of culture and morality. Following Pierre Bourdieu, the object of the study is conceptualised as a field of consumption of political opinions consisting of a space of political opinions or stances, a space of political party preferences, and a space of social positions or opinion holders defined by (among other things) their cultural and economic capital. The field of consumption is examined through multiple correspondence analysis and Euclidean classification. Overall, the field of consumption of political opinions is found to be relatively homologous to the social space. The field of consumption is found to be a two-dimensional space, with one dimension separating left-wing from rightwing opinions and the second distinguishing between socio economic and socio- cultural opinions. The tendency to vote left wing and to have left-leaning socio-economic opinions corresponds to a low total volume of capital and possessions dominated by cultural capital, whereas the tendency to vote right wing and to have right-leaning socio-economic opinions corresponds to a high total volume of capital. Liberal socio-cultural opinions correspond to a high level of possession cultural capital (and its relative weight in the structure of the total possession of capital), whereas the opposite is true for conservative opinions. Furthermore, the socio-cultural dimension is found to harbour two different aspects: liberalism or conservatism with regard to traditional morality and liberalism or conservatism with regard to the idea of a national culture. This thesis also studies how individuals tend to combine opinions from the two dimensions into tangible constellations of opinions.

Diploma thesis reviews the position of the European Union to regulate the business-to-business relations in the retail supply chain and sums up the view of parliamentary political parties in the Czech Republic on the regulation of unfair trading practices in the business-to-business relations. The first chapter defines the behavior of firms in the market structures of perfect and imperfect competition, and specifies the microeconomic effects of economic policy. The second chapter describes the development of retail sector, forms of unfair trading practices, and approaches to solving the problem of unfair trade practices in the Czech Republic and in the European Union. The third chapter presents opinions of political parties in the Czech Republic to regulate the unfair trading practices in the retail supply chain.