Phase transition in a sexual age-structured model of learning foreign languages

The understanding of language competition helps us to predict extinction and survival of languages spoken by minorities. A simple agent-based model of a sexual population, based on the Penna model, is built in order to find out under which circumstances one language dominates other ones. This model considers that only young people learn foreign languages. The simulations show a first order phase transition where the ratio between the number of speakers of different languages is the order parameter and the mutation rate is the control one.Comment: preliminary version, to be submitted to Int. J. Mod. Phys.

Controle de plantas daninhas em pomares de cajueiro.

bitstream/CNPAT/7813/1/ctec_10.pd

Cultivares de cebola e alho para processamento.

Importancia econômica. Aspectos nutricionais. Composição. Nutrientes essenciais. Flavonoides. Flavonois. Antocianinas. Frutooligossacarideos. Compostos de enxofre. Teors de favonoides em cultivares de cebola. Efeito da cura na composição química da cebola. Efeito do cozimento na composição química da cebola.Produtos processados de cebola e alho. Caracteríricas desejáveis nas cultivares para processamento. Teor de sólidos totais. Pungência. Acúcares redutores. Cor. Capacidade de reidratação. Cultivares de cebola e alho para processamento industrial.Trabalho apresentado no 52. Congresso Brasileiro de Olericultura, Salvador, 2012

Indirect lattice evidence for the Refined Gribov-Zwanziger formalism and the gluon condensate ⟨A2⟩\braket{A^2} in the Landau gauge

We consider the gluon propagator $D(p^2)$ at various lattice sizes and spacings in the case of pure SU(3) Yang-Mills gauge theories using the Landau gauge fixing. We discuss a class of fits in the infrared region in order to (in)validate the tree level analytical prediction in terms of the (Refined) Gribov-Zwanziger framework. It turns out that an important role is played by the presence of the widely studied dimension two gluon condensate $\braket{A^2}$. Including this effect allows to obtain an acceptable fit up to 1 \'{a} 1.5 GeV, while corroborating the Refined Gribov-Zwanziger prediction for the gluon propagator. We also discuss the infinite volume extrapolation, leading to the estimate $D(0)=8.3\pm0.5\text{GeV}^{-2}$. As a byproduct, we can also provide the prediction $\braket{g^2 A^2}\approx 3\text{GeV}^2$ obtained at the renormalization scale $\mu=10\text{GeV}$.Comment: 17 pages, 10 figures, updated version, accepted for publication in Phs.Rev.

O efeito tosquia na produção ovina: uma revisão.

bitstream/item/110443/1/O-EFEITO-TOSQUIA-NA-PRODUCAO.pd

Demographic growth and the distribution of language sizes

It is argued that the present log-normal distribution of language sizes is, to a large extent, a consequence of demographic dynamics within the population of speakers of each language. A two-parameter stochastic multiplicative process is proposed as a model for the population dynamics of individual languages, and applied over a period spanning the last ten centuries. The model disregards language birth and death. A straightforward fitting of the two parameters, which statistically characterize the population growth rate, predicts a distribution of language sizes in excellent agreement with empirical data. Numerical simulations, and the study of the size distribution within language families, validate the assumptions at the basis of the model.Comment: To appear in Int. J. Mod. Phys. C (2008