Simulation for competition of languages with an ageing sexual population

Recently, individual-based models originally used for biological purposes revealed interesting insights into processes of the competition of languages. Within this new field of population dynamics a model considering sexual populations with ageing is presented. The agents are situated on a lattice and each one speaks one of two languages or both. The stability and quantitative structure of an interface between two regions, initially speaking different languages, is studied. We find that individuals speaking both languages do not prefer any of these regions and have a different age structure than individuals speaking only one language.Comment: submitted to International Journal of Modern Physics

Mapping the train model for earthquakes onto the stochastic sandpile model

We perform a computational study of a variant of the ``train'' model for earthquakes [PRA 46, 6288 (1992)], where we assume a static friction that is a stochastic function of position rather than being velocity dependent. The model consists of an array of blocks coupled by springs, with the forces between neighbouring blocks balanced by static friction. We calculate the probability, P(s), of the occurrence of avalanches with a size s or greater, finding that our results are consistent with the phenomenology and also with previous models which exhibit a power law over a wide range. We show that the train model may be mapped onto a stochastic sandpile model and study a variant of the latter for non-spherical grains. We show that, in this case, the model has critical behaviour only for grains with large aspect ratio, as was already shown in experiments with real ricepiles. We also demonstrate a way to introduce randomness in a physically motivated manner into the model.Comment: 14 pages and 6 figures. Accepted in European Physical Journal

Ising Ferromagnet: Zero-Temperature Dynamic Evolution

The dynamic evolution at zero temperature of a uniform Ising ferromagnet on a square lattice is followed by Monte Carlo computer simulations. The system always eventually reaches a final, absorbing state, which sometimes coincides with a ground state (all spins parallel), and sometimes does not (parallel stripes of spins up and down). We initiate here the numerical study of ``Chaotic Time Dependence'' (CTD) by seeing how much information about the final state is predictable from the randomly generated quenched initial state. CTD was originally proposed to explain how nonequilibrium spin glasses could manifest equilibrium pure state structure, but in simpler systems such as homogeneous ferromagnets it is closely related to long-term predictability and our results suggest that CTD might indeed occur in the infinite volume limit.Comment: 14 pages, Latex with 8 EPS figure

Uso de videoclipe ambiental com música amazônica no ensino da Língua Portuguesa.

Neste trabalho abordamos os procedimentos metodológicos adotados para o uso em sala de aula de um videoclipe ambiental elaborado para fins de uso didático em atividades de comunicação cientifica e educação ambiental. O videoclipe, com a música Pela cauda de um cometa, de autoria e interpretação de artistas da Amazônia, foi produzido por alunos da Escola E.E.F.M. Marcelo Cândia, com a finalidade de promover a divulgação científica da ciência florestal, ao público leigo. Para validar o videoclipe como uma ferramenta pedagógica de educomunicação científica e ambiental, o mesmo foi utilizado na disciplina de Língua Portuguesa, com uma turma de 41 alunos do 2.º ano do Ensino Médio. Na aplicação, os alunos, em grupos, fizeram análise textual e produziram 10 cartazes que registram a interpretação dos mesmos quanto aos temas abordados, no caso a degradação ambiental do Planeta. Com base nessa experiência analisada, apresentamos recomendações e sugestões de uso do videoclipe como recurso didático para a educação ambiental, como questão transversal

Efeito de diferentes sistemas de aquecimento no desempenho de leitoes.

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Desenvolvimento e caracterização de filmes de TiO2 para aplicação como fotocatalisadores em processos oxidativos avançados.

bitstream/item/77115/1/CT112-2010.pd

Associations between vitamin D levels and depressive symptoms in later life: evidence from the English Longitudinal Study of Ageing (ELSA)

BACKGROUND: A possible role of vitamin D in depression has received considerable attention, especially given the significant disability, mortality, and healthcare costs associated to depression and the high prevalence of vitamin D deficiency. METHODS: We investigated the cross-sectional associations between serum 25-hydroxyvitamin D (25OHD) levels and depressive symptoms (CES-D) in 5,607 older adults from the English Longitudinal Study of Ageing (ELSA). RESULTS: Overall, there was a significant association between low 25OHD levels and elevated depressive symptoms (odds ratio [OR] = 1.58, 95% confidence interval [CI] = 1.20–2.07 for the lowest quartile; OR = 1.45, 95% CI = 1.15–1.83 for <30 nmol/L cut-off and OR = 1.34, 95% CI = 1.10–1.62 for the ≤50 nmol/L cut-off) after adjustment for a wide range of covariates of clinical significance. Fully adjusted models showed that women in the lowest (OR = 1.67, 95% CI = 1.20–2.34) and second lowest (OR = 1.68, 95% CI = 1.20–2.35) quartiles of 25OHD as well as those with 25OHD levels <30 nmol/L (OR = 1.40, 95% CI = 1.06–1.86) and ≤50 nmol/L (OR = 1.35, 95% CI = 1.07–1.72) were more likely to report elevated depressive symptoms. For men, however, this association only remained significant for those with 25OHD levels of <30 nmol/L (OR = 1.60, 95% CI = 1.06–2.42) in the fully adjusted models. CONCLUSIONS: The independent and inverse association found between low 25OHD levels and elevated depressive symptoms suggests that vitamin D deficiency may be a risk factor for late-life depression, particularly among women. Whether our findings have any clinical meaning or not, additional data are needed from well-designed randomized controlled trials of vitamin D for the prevention and treatment of late-life depression

Acesso aberto à informação de solos brasileiros.

O objetivo deste trabalho foi demonstrar as formas de acesso aos dados e as etapas para a realização de consultas públicas, via Internet.CIIC 2014. Nº 14605