Deflationary Models Driven by Matter Creation

A nonsingular deflationary cosmology driven by adiabatic matter creation is proposed. In this scenario there is no preinflationary stage as happens in conventional inflationary models. Deflation starts from a de Sitter spacetime characterized by an arbitrary time scale $H_{I}^{-1}$, which also pins down an initial value for the temperature of the universe. The model evolves continuously towards a slightly modified Friedman-Robertson-Walker universe. The horizon and other well known problems of the standard model are then solved but, unlike in microscopic models of inflation, there is no supercooling and subsequent reheating. Entropy generation is concomitant with deflation and if $H_{I}^{-1}$ is of the order of the Planck time, the present day value of the radiation temperature is deduced. It is also shown that the ``age problem'' does not exist here. In particular, the theoretically favored FRW flat model is old enough to agree with the observations even given the high values of $H_{o}$ suggested by recent measurements.Comment: 17 pages, 2 figures(available from the authors), uses LATE

Periódicos de Oporto, públicos de la ciudad : la construcción de la identidad editorial y las audiencias

The three Oporto daily newspapers O Comércio do Porto, O Primeiro de Janeiro and Jornal de Notícias were founded during the XIX century and steadily grew in prestige and respect amongst the national Portuguese press. These papers began as local and ideological projects supported by political parties and a powerful commercial association but gradually evolved to more comprehensive newspapers with a wider range of lectors. Each particular profile was built through editorial policies which led to strategies of audience identification, underlined by the charisma of their owners and directors. The aim of this study is to identify the engagement processes with readers in their early days and the methodology will rely on sources such as newspapers contents and some other specialized publications. The key moments of evolution in Comércio, Janeiro and Notícias will be tracked by the adaptation to the modernization challenges according to reports, newspapers and some senior journalists’ testimoniesLos periódicos de Oporto O Comércio do Porto, O Primeiro de Janeiro y Jornal de Notícias, surgieron en el siglo XIX y gradualmente se tornaron títulos nacionales de prestigio. Inicialmente dos de ellos eran proyectos ideológicos de partidos políticos locales y el tercero tenía el respaldo de la asociación comercial, pero con el tiempo fueron evolucionando hacia modelos de información más anchos, ampliando el círculo de lectores. El perfil informativo de cada uno se construyó en articulación con públicos específicos y a través de la promoción de procesos de identificación, reforzada por la acción de propietarios y directores carismáticos. El objetivo de este estudio es identificar estas características editoriales y procesos de conquista del público en sus primeras etapas, según una metodología basada en el contenido de los periódicos y publicaciones especializadas. Los momentos clave de la transformación serán identificados por los periódicos, informes y testimonios de periodista

Reflection matrices for the Uq[sl(r∣2m)(2)]U_{q}[sl(r|2m)^{(2)}] vertex model

The graded reflection equation is investigated for the $U_{q}[sl(r|2m)^{(2)}]$ vertex model. We have found four classes of diagonal solutions and twelve classes of non-diagonal ones. The number of free parameters for some solutions depends on the number of bosonic and fermionic degrees of freedom considered.Comment: 30 page

A Note on Commuting Diffeomorphisms on Surfaces

Let S be a closed surface with nonzero Euler characteristic. We prove the existence of an open neighborhood V of the identity map of S in the C^1-topology with the following property: if G is an abelian subgroup of Diff^1(S) generated by any family of elements in V then the elements of G have common fixed points. This result generalizes a similar result due to Bonatti and announced in his paper "Diffeomorphismes commutants des surfaces et stabilite des fibrations en tores".Comment: 16 page

Evolution of ethnocentrism on undirected and directed Barabási-Albert networks

Using Monte Carlo simulations, we study the evolution of contigent cooperation and ethnocentrism in the one-move game. Interactions and reproduction among computational agents are simulated on undirected and directed Barabási-\ud Albert (BA) networks. We first replicate the Hammond-Axelrod model of in-group favoritism on a square lattice and then generalize this model on undirected and directed BA networks for both asexual and sexual reproduction cases. Our simulations demonstrate that irrespective of the mode of reproduction, ethnocentric strategy becomes common even though cooperation is individually costly and mechanisms such as reciprocity or conformity are absent. Moreover, our results indicate that the spread of favoritism toward similar others highly depends on the network topology and the associated heterogeneity of the studied population