The Role of Fermions in Bubble Nucleation

We present a study of the role of fermions in the decay of metastable states of a scalar field via bubble nucleation. We analyze both one and three-dimensional systems by using a gradient expansion for the calculation of the fermionic determinant. The results of the one-dimensional case are compared to the exact results of previous work.Comment: 15 pages, revtex, 9 figure

Repeatability of traits evaluated in a split-plot or factorial experiment.

In this paper repeatability expressions are derived and their respective ANOVA estimators obtained by using split-plot and factorial models, both in a randomized complete block design. The paper also considers different fixed and random effect models and their assumptions and restrictions. Repeatability estimates, such as the correlation between successive measurements (over time) of the same genotype, always have the same value regardless of the model used, and this allows repeatability to be calculated using models based on the mean of the experimental units (mean of blocks) of each genotype in each time. This independence was not observed for repeatability estimates at the upper limit of broad-sense heritability based on the mean of successive measurements (over time) of the same genotype. The repeatability of traits evaluated in experimental trials of different designs is also discussed

Improved semiclassical density matrix: taming caustics

We present a simple method to deal with caustics in the semiclassical approximation to the thermal density matrix of a particle moving on the line. For simplicity, only its diagonal elements are considered. The only ingredient we require is the knowledge of the extrema of the Euclidean action. The procedure makes use of complex trajectories, and is applied to the quartic double-well potential.Comment: 20 pages, 7 figures. Revised version, accepted for publication in Phys. Rev.

Desempenho do híbrido de girassol BRS 321 no Rio Grande do Sul.

bitstream/item/59620/1/girassol-Barneche.pd

Literacia, ensino da leitura e sucesso escolar

Nas últimas décadas, tem se observado uma crescente demanda pelo domínio da linguagem escrita em todas as áreas da vida social (Olson 2009). Essa demanda não se limita apenas ao contexto brasileiro, mas refere-se a um contexto mundial, que hoje coloca o domínio das diversas capacidades de linguagem, em especial das capacidades de leitura e escrita, como condição para acesso ao conhecimento, à participação social e o exercício efetivo da cidadania. O domínio de tais capacidades refere-se a um certo tipo ou nível de literacia que vai além da descodificação, diz respeito às diversas capacidades de leitura e escrita necessárias em diferentes práticas sociais. Partindo de uma parceria de investigação entre instituições de ensino superior em Portugal e no Brasil, temos vindo a reflectir sobre questões de currículo nos dois países.ABSTRACT In the last decades, a growing demand for the domain of written language in all areas of social life has been observed (Olson 2009). This demand is not limited to the Brazilian context, but concerns a global context which now sets the domain of different language skills, especially skills in reading and writing as a condition for access to knowledge, social participation and effective exercise of citizenship. The domain of these skills concerns a certain type or level of literacy that goes beyond decoding, refers to the different reading and writing skills required in different social practices. From a research partnership between universities and research centers in Portugal and Brazil, we have been reflecting on issues of curriculum in both countries