Quatro vezes Lula-lá A imagem pública de Lula no horário eleitoral nas quatro campanhas presidenciais

Descreve-se aqui a formação da Imagem Pública de Luis Inácio Lula da Silva através do Horário Gratuito de Propaganda Eleitoral, nas quatro eleições presidenciais que marcaram o período de democratização do País: 1989, 1994, 1998 e 2002. O fato de um candidato contrário às elites, três vezes derrotado em eleições anteriores, conseguir convencer através da mídia a elegê-lo eleitores que votavam antes em seus adversários, demonstra que a democracia representativa brasileira é institucionalmente compatível com regime de informação imposto pelos meios de comunicação de massa na sociedade atual? Além de comprovar a preponderância da Imagem Pública em processos eleitorais em que o Cenário de Representação da Política se caracteriza pela imprevisibilidade, a pesquisa constatou ainda que a atual luta política, mais que uma luta meramente pela visibilidade imposta pela TV e pelos meios de comunicação em geral ainda é uma disputa política. E que a mídia enquadra a política, mas também é por ela agendada, principalmente em momentos de grande incerteza política e/ou pouca previsibilidade eleitoral

O regime da memória através dos diários virtuais: o caso dos blogs

CARVALHO, Luciana Moreira.;CARVALHO, Monica Marques. O registro da memória através dos diários virtuais:o caso dos blogs.Em Questão, Porto Alegre, v. 11, n. 1, p. 53-66, jan./jun. 2005.ISSN 1808-5245. Disponivel em:dex.php/EmQuestao/article/viewArticle/111>. Acesso em: 04 out. 2010. ão

Estudo da transição de fase da percolação através da entropia da informação

Various physical systems have dynamics that can be modeled by percolation processes. Percolation is used to study issues ranging from fluid diffusion through disordered media to fragmentation of a computer network caused by hacker attacks. A common feature of all of these systems is the presence of two non-coexistent regimes associated to certain properties of the system. For example: the disordered media can allow or not allow the flow of the fluid depending on its porosity. The change from one regime to another characterizes the percolation phase transition. The standard way of analyzing this transition uses the order parameter, a variable related to some characteristic of the system that exhibits zero value in one of the regimes and a nonzero value in the other. The proposal introduced in this thesis is that this phase transition can be investigated without the explicit use of the order parameter, but rather through the Shannon entropy. This entropy is a measure of the uncertainty degree in the information content of a probability distribution. The proposal is evaluated in the context of cluster formation in random graphs, and we apply the method to both classical percolation (Erd¨os- R´enyi) and explosive percolation. It is based in the computation of the entropy contained in the cluster size probability distribution and the results show that the transition critical point relates to the derivatives of the entropy. Furthermore, the difference between the smooth and abrupt aspects of the classical and explosive percolation transitions, respectively, is reinforced by the observation that the entropy has a maximum value in the classical transition critical point, while that correspondence does not occurs during the explosive percolation.

Estudo da transição de fase da percolação através da entropia da informação

Various physical systems have dynamics that can be modeled by percolation processes. Percolation is used to study issues ranging from fluid diffusion through disordered media to fragmentation of a computer network caused by hacker attacks. A common feature of all of these systems is the presence of two non-coexistent regimes associated to certain properties of the system. For example: the disordered media can allow or not allow the flow of the fluid depending on its porosity. The change from one regime to another characterizes the percolation phase transition. The standard way of analyzing this transition uses the order parameter, a variable related to some characteristic of the system that exhibits zero value in one of the regimes and a nonzero value in the other. The proposal introduced in this thesis is that this phase transition can be investigated without the explicit use of the order parameter, but rather through the Shannon entropy. This entropy is a measure of the uncertainty degree in the information content of a probability distribution. The proposal is evaluated in the context of cluster formation in random graphs, and we apply the method to both classical percolation (Erd¨os- R´enyi) and explosive percolation. It is based in the computation of the entropy contained in the cluster size probability distribution and the results show that the transition critical point relates to the derivatives of the entropy. Furthermore, the difference between the smooth and abrupt aspects of the classical and explosive percolation transitions, respectively, is reinforced by the observation that the entropy has a maximum value in the classical transition critical point, while that correspondence does not occurs during the explosive percolation.