Derived Subgroups of Fixed Points in Profinite Groups

The main result of this paper is the following theorem. Let q be a prime, A an elementary abelian group of order q^3. Suppose that A acts as a coprime group of automorphisms on a profinite group G in such a manner that C_G(a)' is periodic for each nontrivial element a in A. Then G' is locally finite.Comment: To appear in Glasgow Mathematical Journal (2011). 11 page

The Anatomy of a Scientific Rumor

The announcement of the discovery of a Higgs boson-like particle at CERN will be remembered as one of the milestones of the scientific endeavor of the 21st century. In this paper we present a study of information spreading processes on Twitter before, during and after the announcement of the discovery of a new particle with the features of the elusive Higgs boson on 4th July 2012. We report evidence for non-trivial spatio-temporal patterns in user activities at individual and global level, such as tweeting, re-tweeting and replying to existing tweets. We provide a possible explanation for the observed time-varying dynamics of user activities during the spreading of this scientific "rumor". We model the information spreading in the corresponding network of individuals who posted a tweet related to the Higgs boson discovery. Finally, we show that we are able to reproduce the global behavior of about 500,000 individuals with remarkable accuracy.Comment: 11 pages, 8 figure

Partners and relatives. Articulating modernity and tradition in Portuguese large family firms

Large family enterprises are different from other kinds of large firms in Portugal. The formation of kinship relationships found in the social context of large family firms is also of a different nature than those found in other social groups. Both features are due to the overlapping of family and economic relations that characterises large family firms. Based on research developed among large Portuguese family firms, this article analyses changes in the succession for leadership positions in these organisations over the last 100 years. Although these wealth entrepreneurial families are strongly rooted on traditional social values (as they claim their aristocratic origin) they develop strong strategies to integrate modernity symbols and meritocratic criteria in the incorporation of relatives into the firm. I will argue that the articulation of family tradition with modern economic rationality is central to the survival of traditional large family firms in contemporary world economy.info:eu-repo/semantics/publishedVersio

Sistema policultivar de milho: tecnologia para reduzir os riscos de producao no Piaui.

A pesquisa tem mostrado que quando se planta cultivares com caracteristicas de florescimento diferentes o risco de perdas de colheitas e bemmenor, mesmo em condicoes climaticas adversas. O sistema policultivar de milho e uma das maneiras de como o agricultor pode amenizar os riscos de perder sua lavoura, bastando para isso que ele escolha cultivares de ciclos diferentes, que semeadas na mesma epoca, terao maior possibilidade de escape, no caso de estiagens prolongadas. Sao recomendadasas cultivares hibridas com floracao entre 50 e 55 dias: PIONEE 6875, XL-560, AG 64 A, SAVE 342 e DK 550. O plantio deve ser feito no espacamento de 1,00 x 0,40m deixando-se duas plantas por cova.bitstream/item/95916/1/CT290001.pd

Sliding Blocks Revisited: A simulational Study

A computational study of sliding blocks on inclined surfaces is presented. Assuming that the friction coefficient $\mu$ is a function of position, the probability $P(\lambda)$ for the block to slide down over a length $\lambda$ is numerically calculated. Our results are consistent with recent experimental data suggesting a power-law distribution of events over a wide range of displacements when the chute angle is close to the critical one, and suggest that the variation of $\mu$ along the surface is responsible for this.Comment: 6 pages, 4 figures. submitted to Int. J. Mod. Phys. (Proc. Brazilian Wokshop on Simulational Physics

On Matrix Superpotential and Three-Component Normal Modes

We consider the supersymmetric quantum mechanics (SUSY QM) with three- component normal modes for the Bogomol'nyi-Prasad-Sommerfield (BPS) states. An explicit form of the SUSY QM matrix superpotential is presented and the corresponding three-component bosonic zero-mode eigenfunction is investigated.Comment: 17 pages, no figure. Paper accepted for publication in Journal of Physics A: Mathematical and Theoretica

Estimativas de herdabilidade e correlações genéticas de produções parciais e total de leite de cabras mestiças.

O objetivo desde trabalho foi estimar as herdabilidades, repetibilidades e correlações genéticas para as produções parciais acumuladas e produção total de leite de cabras mestiças. Os dados utilizados foram obtidos de 29.703 controles leiteiros, resultantes de 1055 lactações de 400 cabras F1 Pardo-Alpina x Moxotó no período de 1988 a 1997, pertencente ao CNPC-EMBRAPA. As estimativas dos componentes de covariâncía foram obtidas pelo método da Máxima Verossimilhança Restrita, por meio do modelo animal utilizando o Programa Multiple Trait Derivate-Free Restricted Maximum Likelihood (MTDFREML). Estudou-se o efeito fixo estação-ano de parição e ordem de lactaçâo e como covariável o peso da matriz ao parto (linear) e o peso total das crias (linear). Como efeito aleatório, inclui-se o efeito genético aditivo e o efeito não correlacionado de ambiente permanente. As estimativas obtidas de herdabilidade e repetibilidade para as produções parciais aos 30, 60, 90, 120,150 dias de lactaçâo e para a produção de leite total foram 0,27 + 0,15; 0,31 + 0,15; 0,31+ 0,15; 0,31 + 0,15; 0,30 + 0,15; 0,22 + 0,15 e 0,64; 0,51; 0,58; 0,54; 0,55 e 0,48, respectivamente. As características foram correlacionadas geneticamente variando na mesma direção e sentido. As correlações genéticas obtidas encontraram-se no intervalo de 0,68 a 0,98.Disponível em Separata