A dark energy multiverse

We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time, which can be either big bang/crunchs or big rips singularities. Classicaly these solutions can be regarded as associated with multiverse scenarios, being those corresponding to phantom energy that may describe the current accelerating universe

Lorentzian wormholes generalize thermodynamics still further

This paper deals with some thermodynamical aspects of Lorentzian wormholes, including the formulation of the three main laws and the consideration of a possible thermal emission made up of some sort of phantom radiation coming out from the wormhole at a negative temperature. In order for these topics to be consistently developed we have used a 2+2 formalism first advanced by Hayward for spherically symmetric spacetimes, where a generalized surface gravity is defined on the trapping horizon. Our results generalize still further those of the already generalized gravitational thermodynamics. © 2009 IOP Publishing Ltd.This work was supported by a Spanish MEC Research Project No. FIS2008-06332/FIS.Peer Reviewe

Los alumnos prefieren diferentes estrategias didácticas de la enseñanza de las ciencias en función de sus características motivacionales

We carried out empirical research into the relationship between students' motivational pattems and their preferences for different teaching procedures in science education. According to the results obtained, students tend to prefer those teaching procedures and strategies that allow their motivational needs to be met and reject those conflicting with them

Public spaces and immigration in Seville: building citizenship or reproducing power relationships?

Many studies have focused on the importance of immigrants participating in the public spaces of the cities where they have settled in order to become integrated. Our research, in contrast, demonstrates the importance of contextualizing participation within the framework of the power relationships that justify and give meaning to certain practices of discipline and control. We look at one concrete example in Seville (Spain): the regulation of the Latin American sports leagues of San Jeronimo. This case demonstrates the central role of public space in monitoring and controlling immigrants and in the dynamics of resistance they develop.info:eu-repo/semantics/submittedVersio

High-Order Harmonic Generation from the Cu(111) surface

We investigate theoretically the origin behind the formation of the plateau and cutoff structures in the high-harmonic spectra produced after the interaction of a near-infrared laser pulse with a metal surface. We use a wave packet propagation scheme and a one dimensional description of the Cu(111) surfac

Isotropic extensions of the vacuum solutions in general relativity

In this work, we obtain isotropic extensions of the usual spherically symmetric vacuum geometries in general relativity. Exact and perturbative solutions are derived. The classes of geometries obtained include black holes in compact and noncompact universes, wormholes in the interior region of cosmological horizons, and anti-de Sitter geometries with excess/deficit solid angle. The tools developed here are applicable in more general contexts.Comment: 12 pages, 6 figures. Version to be published in Physical Review

Entanglement entropy of an accelerating universe

We have considered the existence of a dependence of the entanglement entropy on the cosmological horizon surface area also in several accelerating models of the current universe both for a quintessence scalar field and for a phantom-energy scenario. It is shown that if a quintessence vacuum cosmic field is considered then, though the case for w>-1 satisfies a second law for entanglement entropy, when w<-1 such a law is violated. It is finally noted that the entanglement entropy and the distinct formulations of cosmic holography share common future surfaces which are optimal screen for the latter descriptions. © 2012 American Physical Society.This work was supported by MICINN under Research Project FIS2008- 06332.Peer Reviewe

Ideas de los alumnos acerca del mol. Estudio curricular

In this paper a display is made of the controversy about the concept of m01 and the convenience of introducing it in the school "curricula" at the age in which nowadays is made. The results we have obtained from the research carried out on the difficulties experienced by 15 to 19 year old students in understanding this concept and other related concepts are given