Anisotropias da radiação cósmica de fundo e vínculos em modelos com decaimento do vácuo

Many astronomical observations in the last few years are strongly suggesting that the current Universe is spatially flat and dominated by an exotic form of energy. This unknown energy density accelerates the universe expansion and corresponds to around 70% of its total density being usually called Dark Energy or Quintessence. One of the candidates to dark energy is the so-called cosmological constant (Λ) which is usually interpreted as the vacuum energy density. However, in order to remove the discrepancy between the expected and observed values for the vacuum energy density some current models assume that the vacuum energy is continuously decaying due to its possible coupling with the others matter fields existing in the Cosmos. In this dissertation, starting from concepts and basis of General Relativity Theory, we study the Cosmic Microwave Background Radiation with emphasis on the anisotropies or temperature fluctuations which are one of the oldest relic of the observed Universe. The anisotropies are deduced by integrating the Boltzmann equation in order to explain qualitatively the generation and c1assification of the fluctuations. In the following we construct explicitly the angular power spectrum of anisotropies for cosmologies with cosmological constant (ΛCDM) and a decaying vacuum energy density (Λ(t)CDM). Finally, with basis on the quadrupole moment measured by the WMAP experiment, we estimate the decaying rates of the vacuum energy density in matter and in radiation for a smoothly and non-smoothly decaying vacuum

Música em projetos socioassistenciais governamentais: práticas e concepções culturais no Serviço de Convivência e Fortalecimento de Vínculos em Natal/RN

This present research focus at the teaching of music in social programs, it discuss about the teaching concepts that permeates the educational-musical practice presents in Serviço de Convivência e Fortalecimento de Vínculos (SCFV), of Complexo Dom Bosco, in Natal-RN. The Objective is to reflect upon the music teaching concepts and the relations between musical knowledge and culture. For this, it was problematized the concepts of music teaching and learning in governmental social projects through theoretical and empirical research. After this step, it was studied the cultural aspects involving the routine in the institutions the influenced the music learning at Serviço de Convivência e Fortalecimento de Vínculos, furthermore, and how these aspects are present in the constitution of the paradigms that involve music teaching. For this, it was used a qualitative approach and a case study as type of research. As data capture tool it was used the ethnographic write, photography, interviews as a Facilitator of music with the students of the program, and video recordings of musical learning situations. Theoretical support it was used authors who study the complexity, culture and music teaching in social projects. Finally, the conclusion is that musical learning, in the SCFV context, is involved of cultural conceptions steeped to the Oratório Dom Bosco space and the same time the Brazilian Social Assistance Policy. Sometimes these concepts are contradictory: discipline, leadership and combat social exclusion refer to dialogical cultural hologram of the institutions involved in the music education process.