Universal Aspects of U(1)U(1) Gauge Field Localization on Branes in DD-dimensions

In this work, we study the general properties of the $D$-vector field localization on $(D-d-1)$-brane with co-dimension $d$. We consider a conformally flat metric with the warp factor depending only on the transverse extra dimensions. We employ the geometrical coupling mechanism and find an analytical solution for the $U(1)$ gauge field valid for any warp factor. Using this solution we find that the only condition necessary for localization is that the bulk geometry is asymptotically AdS. Therefore, our solution has an universal validity for any warp factor and is independent of the particular model considered. We also show that the model has no tachyonic modes. Finally, we study the scalar components of the $D$-vector field. As a general result, we show that if we consider the coupling with the tensor and the Ricci scalar in higher co-dimensions, there is an indication that both sectors will be localized. As a concrete example, the above techniques are applied for the intersecting brane model. We obtain that the branes introduce boundary conditions that fix all parameters of the model in such a way that both sectors, gauge and scalar fields, are confined.Comment: 26 pages, 5 figures, Accepted version for publication in JHE

Criatividade e ensino

O objetivo do presente artigo é decorrer sobre a criatividade no ensino e mostrar que o desenvolvimento do potencial criador durante o ensino é fundamental para uma melhora na educação

Near-Infrared Time-Series Photometry in the Field of Cygnus OB2 Association I - Rotational Scenario For Candidate Members

In the last decades, the early pre main sequence stellar rotational evolution picture has been constrained by studies targeting different young regions at a variety of ages. Observational studies suggest a mass-rotation dependence, and for some mass ranges a connection between rotation and the presence of a circumstellar disk. Not still fully explored, though, is the role of environmental conditions on the rotational regulation. We investigate the rotational properties of candidate members of the young massive association Cygnus OB2. The Stetson variability index, Lomb-Scargle periodogram, Saunders statistics, string/rope length method, and visual verification of folded light curves were applied to select 1224 periodic variable stars. Completeness and contamination of the periodic sample was derived from Monte Carlo simulations, out of which 894 periods were considered reliable. Our study was considered reasonably complete for periods from 2 to 30 days. The general rotational scenario seen in other young regions is confirmed by Cygnus OB2 period distributions, with disked stars rotating on average slower than non-disked stars. A mass-rotation dependence was also verified, but as in NGC 6530, lower mass stars are rotating on average slower than higher mass stars, with an excess of slow rotators among the lower mass population. The effect of the environment on the rotational properties of the association was investigated by re-analysing the results while taking into account the incident UV radiation arising from O stars in the association. Results compatible with the disk-locking scenario were verified for stars with low UV incidence, but no statistical significant relation between rotation and disk presence was verified for stars with high UV incidence suggesting that massive stars can have an important role on regulating the rotation of nearby low mass stars.Comment: Submitted on December 23, 201

A repressão ao potencial criador

Made available in DSpace on 2016-10-10T03:51:47Z (GMT). No. of bitstreams: 5 A repressão ao Pontencial Criador.pdf: 880446 bytes, checksum: dea6bc6e1b421b85c8653c5708eda262 (MD5) license_url: 52 bytes, checksum: 2f32edb9c19a57e928372a33fd08dba5 (MD5) license_text: 24259 bytes, checksum: f1f24f769b03eb8f9cd3f53c1090841c (MD5) license_rdf: 24658 bytes, checksum: 9d3847733d3c0b59c7c89a1d40d3d240 (MD5) license.txt: 1872 bytes, checksum: 9ede5d1aaff3f6277cd24454ee44422e (MD5) Previous issue date: 1989SimPublicad

Dados preliminares da estrutura genética - bioquimica do gado Nelore (Bos indicus) da Fazenda Canchim.

Estudo do rebanho Nelore da Fazenda Canchim, quanto aos marcadores genético - bioquímicos. levando em conta os diferentes fenótipos detectados, a população mostrou-se estar em equilíbrio.Resumo

Desempenho produtivo de fêmeas das raças Canchim e Nelore. I. Desenvolvimento e puberdade.

Avaliar a eficiência produtiva da raça Canchim em comparação a raça Nelore; Apresenta os resultados referentes aos pesos dos animais e as idades e pesos a puberdade e de entrada em reprodução

Pesos de bovinos Nelores e cruzados Charolês X Nelores.

Comparação dos pesos ao nascimento, desmama e ao sobreano de animais Nelores e de vários graus de sangue Charolês Nelore

Modeling the Halpha line emission around classical T Tauri stars using magnetospheric accretion and disk wind models

Spectral observations of classical T Tauri stars show a wide range of line profiles, many of which reveal signs of matter inflow and outflow. Halpha is the most commonly observed line profile due to its intensity, and it is highly dependent on the characteristics of the surrounding environment of these stars. Our aim is to analyze how the Halpha line profile is affected by the various parameters of our model which contains both the magnetospheric and disk wind contributions to the Halpha flux. We used a dipolar axisymmetric stellar magnetic field to model the stellar magnetosphere and a modified Blandford & Payne model was used in our disk wind region. A three-level atom with continuum was used to calculate the required Hydrogen level populations. We use the Sobolev approximation and a ray-by-ray method to calculate the integrated line profile. Through an extensive study of the model parameter space, we have investigated the contribution of many of the model parameters on the calculated line profiles. Our results show that the Halpha line is strongly dependent on the densities and temperatures inside the magnetosphere and the disk wind region. The bulk of the flux comes, most of the time, from the magnetospheric component for standard classical T Tauri stars parameters, but the disk wind contribution becomes more important as the mass accretion rate, the temperatures and densities inside the disk wind increase. We have also found that most of the disk wind contribution to the Halpha line is emitted at the innermost region of the disk wind. Models that take into consideration both inflow and outflow of matter are a necessity to fully understand and describe classical T Tauri stars.Comment: 15 pages, 9 figures, accepted for publication in Astronomy & Astrophysics. Revised version with English correction

Inventory of educational practices that favor creativity in higher education level

Este estudo teve como objetivo construir e validar um instrumento que permitisse avaliar a percepção de estudantes universitários quanto à extensão em que seus professores vinham apresentando comportamentos e implementando práticas docentes que favorecem o desenvolvimento e a expressão da criatividade do aluno. O instrumento denominado Inventário de Práticas Docentes era composto de 37 itens relativos a diversas dimensões da criatividade. Este instrumento foi aplicado em 1068 estudantes de universidades pública e privada. Foi efetuada uma análise fatorial e 4 fatores foram gerados: Incentivo a Novas Idéias, Clima para Expressão de Idéias, Avaliação e Metodologia de Ensino e Interesse pela Aprendizagem do Aluno. Os coeficientes a de fidedignidade obtidos para os fatores foram superiores a 0,72. Os resultados indicam que o inventário discrimina distintas dimensões do comportamento docente que são relevantes para o desenvolvimento da criatividade, constituindo-se em um instrumento útil para fins de pesquisa e diagnóstico de práticas docentes.The purpose of this study was to construct and validate an instrument that assessed university students' perception with respect to what extent their teachers had presented behaviors and implemented educational practices that favoured the development and expression of students' creativity. The instrument was named Inventory of Educational Practices and consisted of 37 itens related to distinct dimensions of creativity. This instrument was administered to 1068 students from public and private universities. A factorial analysis was conducted and four factors were generated: Incentive to New Ideas, Climate for the Expression of Ideas, Evaluation and Methodology of Teaching, and Interest for the Student's Learning. The alpha coefficients of reliability for all factors were above .72. The results indicated that the inventory discriminates distinct dimensions of teacher behavior that are relevant to the development of creativity, being an useful instrument for researching and diagnosing educational practices