Universality of the Network and Bubble Topology in Cosmological Gravitational Simulations

Using percolation statistics we, for the first time, demonstrate the universal character of a network pattern in the real space, mass distributions resulting from nonlinear gravitational instability of initial Gaussian fluctuations. Percolation analysis of five stages of the nonlinear evolution of five power law models reveals that all models show a shift toward a network topology if seen with high enough resolution. However, quantitatively, the shift is significantly different in different models: the smaller the spectral index ,n, the stronger the shift. On the contrary, the shift toward the "bubble" topology is characteristic only for the n <= -1 models. We find that the mean density of the percolating structures in the nonlinear density distributions generally is very different from the density threshold used to identify them and corresponds much better to a visual impression. We also find that the maximum of the number of structures (connected regions above or below a specified density threshold) in the evolved, nonlinear distributions is always smaller than in Gaussian fields with the same spectrum, and is determined by the effective slope at the cutoff frequency.Comment: The paper is 26 pages long. The latex file uses aasms.sty as a style file. There are 5 figures and 2 tables included

Evidence for Filamentarity in the Las Campanas Redshift Survey

We apply Shapefinders, statistical measures of `shape' constructed from two dimensional partial Minkowski functionals, to study the degree of filamentarity in the Las Campanas Redshift Survey (LCRS). In two dimensions, three Minkowski functionals characterise the morphology of an object, they are: its perimeter (L), area (S), and genus. Out of L and S a single dimensionless Shapefinder Statistic, F can be constructed (0 <=F <=1). F acquires extreme values on a circle (F = 0) and a filament (F = 1). Using F, we quantify the extent of filamentarity in the LCRS by comparing our results with a Poisson distribution with similar geometrical properties and having the same selection function as the survey. Our results unambiguously demonstrate that the LCRS displays a high degree of filamentarity both in the Northern and Southern galactic sections a result that is in general agreement with the visual appearance of the catalogue. It is well known that gravitational clustering from Gaussian initial conditions gives rise to the development of non-Gaussianity reflected in the formation of a network-like filamentary structure on supercluster scales. Consequently the fact that the smoothed LCRS catalogue shows properties consistent with those of a Gaussian random field (Colley 1997) whereas the unsmoothed catalogue demonstrates the presence of filamentarity lends strong support to the conjecture that the large scale clustering of galaxies is driven by gravitational instability.Comment: Accepted for publication in Ap

A agroindústria e o setor agropecuário - nota incidental sobre o tema.

Este trabalho tem como principal objetivo destacar a importância da agroindústria não só para o país, mas, de modo específico, para o setor rural. Dada a relevância da agroindústria na conjuntura atual, os autores procuraram reunir idéias formadas não são com leituras de artigos sobre o tema, mas também oriundas de diversas discussões travadas entre si e com técnicos desta área, esperando com isto contribuir para o desenvolvimento do processo de agroindustrialização, de fundamental importância para o setor agropecuário nacional. Inicia-se o trabalho com uma caracterização da agroindústria, salientando-se, em seguida, sua importância e as diferentes contribuições que apresenta para o sistema de produção de alimentos. Ressalta-se o papel que o Sistema Brasileiro de Assistência Técnica e Extensão Rural (SIBRATER) pode desempenhar, as falhas que vem apresentando, procurando, finalmente, sugerir algumas edidas de ação, no curto, médio e longo prazos, para o desenvolvimento das agroindústrias no país

Desempenho acadêmico de doutores egressos do Programa de Pós-Graduação em Medicina Ciências Médicas da Faculdade de Medicina da UFRGS

Introdução: embora, no Brasil, muito tenha sido feito para estimular a criação e manutenção de programas de pós-graduação ainda há carência de meios para avaliar e para mensurar a evolução profissional dos egressos. O objetivo é compreender a trajetória dos Doutores formados pelo Programa de Pós-Graduação em Medicina Ciências Médicas (PPGCM), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul (UFRGS) e propor um índice de desempenho acadêmico e de inserção profissional. Métodos: foi realizado um estudo transversal. Foram coletados dados dos Currículos Lattes dos egressos de doutorado do Programa de Pós-Graduação em Medicina: Ciências Médicas (PPGCM), no período de 1987 a 2014. Foram extraídos apenas os dados pertinentes a sua origem, curso de graduação e de mestrado, produção intelectual, inserção acadêmica e a posição profissional. Resultados: foram analisados 324 doutores egressos, 221 eram graduados em Medicina. Foram utilizadas as variáveis: graduação em medicina, vínculo laboral em universidade pública, exerce atividade como orientador em nível de doutorado, exerce atividade como orientador em nível de mestrado, bolsista de produtividade em pesquisa do CNPq e possui registro do índice H no currículo Lattes. O coeficiente de determinação (R2) demonstrou que as variáveis incluídas no modelo explicam 99% do modelo hierárquico. Conclusão: os resultados demonstram que os egressos têm contribuído para a construção de conhecimento qualificado disseminado em jornais de circulação internacional, formação de recursos humanos, interagir e criar parcerias em seu ambiente de trabalho, gerenciar e repassar o conhecimento, bem como para fomentar o conhecimento na área das ciências médicas com relevância regional, nacional e internacional

Autism Spectrum Disorder and mental health problems: patterns of difficulties and longitudinal trajectories in a population-based twin sample

There is increasing concern regarding additional psychiatric problems that co-occur with Autism Spectrum Disorder (ASD), as reflected in recent changes to diagnostic schemes. However, there remains little research with population-based samples across childhood. We report on additional problems, as measured by the Strengths and Difficulties Questionnaire, in a population-based sample of 135 twins with ASD, 55 non-ASD co-twins, and 144 comparison twins low in ASD traits. Frequencies, associated demographic factors, and changes in mental health difficulties from age 4 to 13 years are presented. Our data confirm the high rates of additional difficulties reported in previous studies, and suggest that the profile, associated risk factors and longitudinal course of additional difficulties in ASD may differ from those in typically-developing populations

TEASING: a fast and accurate approximation for the low multipole likelihood of the Cosmic Microwave Background temperature

We explore the low-l likelihood of the angular spectrum C(l) of masked CMB temperature maps using an adaptive importance sampler. We find that, in spite of a partial sky coverage, the likelihood distribution of each C(l) closely follows an inverse gamma distribution. Our exploration is accurate enough to measure the inverse gamma parameters along with the correlation between multipoles. Those quantities are used to build an approximation of the joint posterior distribution of the low-l likelihood. The accuracy of the proposed approximation is established using both statistical criteria and a mock cosmological parameter fit. When applied to the WMAP5 data set, this approximation yields cosmological parameter estimates at the same level of accuracy as the best current techniques but with very significant speed gains.Comment: 10 pages, 10 figures, submitted to MNRA

Analytic philosophy for biomedical research: the imperative of applying yesterday's timeless messages to today's impasses

The mantra that "the best way to predict the future is to invent it" (attributed to the computer scientist Alan Kay) exemplifies some of the expectations from the technical and innovative sides of biomedical research at present. However, for technical advancements to make real impacts both on patient health and genuine scientific understanding, quite a number of lingering challenges facing the entire spectrum from protein biology all the way to randomized controlled trials should start to be overcome. The proposal in this chapter is that philosophy is essential in this process. By reviewing select examples from the history of science and philosophy, disciplines which were indistinguishable until the mid-nineteenth century, I argue that progress toward the many impasses in biomedicine can be achieved by emphasizing theoretical work (in the true sense of the word 'theory') as a vital foundation for experimental biology. Furthermore, a philosophical biology program that could provide a framework for theoretical investigations is outlined

Tolerance for 8-oxoguanine but not thymine glycol in alignment-based gap filling of partially complementary double-strand break ends by DNA polymerase λ in human nuclear extracts

Ionizing radiation induces various clustered DNA lesions, including double-strand breaks (DSBs) accompanied by nearby oxidative base damage. Previous work showed that, in HeLa nuclear extracts, DSBs with partially complementary 3′ overhangs and a one-base gap in each strand are accurately rejoined, with the gaps being filled by DNA polymerase λ. To determine the possible effect of oxidative base damage on this process, plasmid substrates were constructed containing overhangs with 8-oxoguanine or thymine glycol in base-pairing positions of 3-base (-ACG or -GTA) 3′ overhangs. In this context, 8-oxoguanine was well tolerated by the end-joining machinery when present at one end of the break, but not when present at both ends. Thymine glycol was less well tolerated than 8-oxoguanine, reducing gap filling and accurate rejoining by at least 10-fold. The results suggest that complex DSBs can be accurately rejoined despite the presence of accompanying base damage, but that nonplanar bases constitute a major barrier to this process and promote error-prone joining. A chimeric DNA polymerase, in which the catalytic domain of polymerase λ was replaced with that of polymerase β, could not substitute for polymerase λ in these assays, suggesting that this domain is specifically adapted for gap filling on aligned DSB ends