Ab initio study of the CE magnetic phase in half-doped manganites: Purely magnetic versus double exchange description

The leading electronic interactions governing the local physics of the CE phase of half-doped manganites are extracted from correlated ab initio calculations performed on an embedded cluster. The electronic structure of the low-energy states is dominated by double exchange configurations and O-2$p_{\sigma}$ to Mn-3d charge transfer configurations. The model spectra of both a purely magnetic non-symmetric Heisenberg Hamiltonian involving a magnetic oxygen and two non-symmetric double exchange models are compared to the \textit{ab initio} one. While a satisfactory agreement between the Heisenberg spectrum and the calculated one is obtained, the best description is provided by a double exchange model involving excited non-Hund atomic states. This refined model not only perfectly reproduces the spectrum of the embedded cluster in the crystal geometry, but also gives a full description of the local double-well potential energy curve of the ground state (resulting from the interaction of the charge localized electronic configurations) and the local potential energy curves of all excited states ruled by the double exchange mechanism

Electron correlations and bond-length fluctuations in copper oxides: from Zhang--Rice singlets to correlation bags

We perform first principles, multiconfiguration calculations on clusters including several CuO$_6$ octahedra and study the ground-state electron distribution and electron--lattice couplings when holes are added to the undoped $d^9 p^6$ configuration. We find that the so-called Zhang--Rice state on a single CuO$_4$ plaquette is nearly degenerate with a state whose leading configuration is of the form Cu $d^9$-- O $p^5$-- Cu $d^9$. A strong coupling between the electronic and nuclear motion gives rise to large inter-site charge transfer effects for half-breathing displacements of the oxygen ions. Under the assumption of charge segregation into alternating hole-free and hole-rich stripes of Goodenough \cite{jbg_02,jbg_03}, our results seem to support the vibronic mechanism and the traveling charge-density wave model from Refs.\cite{jbg_02,jbg_03} for the superconductivity in copper oxides.Comment: submitted to Phys. Rev.

Renormalization of the quasiparticle hopping integrals by spin interactions in layered copper oxides

Holes doped within the square CuO2 network specific to the cuprate superconducting materials have oxygen 2p character. We investigate the basic properties of such oxygen holes by wavefunction-based quantum chemical calculations on large embedded clusters. We find that a 2p hole induces ferromagnetic correlations among the nearest-neighbor Cu 3d spins. When moving through the antiferromagnetic background the hole must bring along this spin polarization cloud at nearby Cu sites, which gives rise to a substantial reduction of the effective hopping parameters. Such interactions can explain the relatively low values inferred for the effective hoppings by fitting the angle-resolved photoemission data. The effect of the background antiferromagnetic couplings of renormalizing the effective nearest-neighbor hopping is also confirmed by density-matrix renormalization-group model Hamiltonian calculations for chains and ladders of CuO4 plaquettes

La problemática de la alimentación religiosa y de convicción en los centros educativos

AbstractAs a consequence of the sociological change undergone in Spain in what concerns religious beliefs, claims have arisen in the educational milieu, and among them the request of menus adapted to the religious prescriptions. In the present article we are intended to deal with such issue and to analyze whether it exists or not, as a result of the right to freedom of religion, the right to be offered menus by the educational institutions that could respond to the express request from the students. With this aim, the constitutional principles are studied, as well as the current legislation and the case-law decisions, in order to conclude with a proposal of «reasonable accommodation» as in the Law of Canada.ResumenComo consecuencia del cambio sociológico vivido en España en materia de creencias religiosas, han surgido algunas reivindicaciones en el ámbito escolar, entre ellas la petición de menús adaptados a las convicciones religiosas. El presente trabajo aborda esta problemática y analiza si existe, como consecuencia del derecho de libertad religiosa, un derecho a que los menús ofrecidos en los centros escolares puedan responder a la petición expresa de los alumnos. Para ello se analizan los principios constitucionales, así como la legislación vigente y las decisiones jurisprudenciales, para concluir con una propuesta de acomodo razonable al estilo canadiense.AbstractAs a consequence of the sociological change undergone in Spain in what concerns religious beliefs, claims have arisen in the educational milieu, and among them the request of menus adapted to the religious prescriptions. In the present article we are intended to deal with such issue and to analyze whether it exists or not, as a result of the right to freedom of religion, the right to be offered menus by the educational institutions that could respond to the express request from the students. With this aim, the constitutional principles are studied, as well as the current legislation and the case-law decisions, in order to conclude with a proposal of «reasonable accommodation» as in the Law of Canada

Diálogo interreligioso y gobernanza ciudadana

SUMARIO: 1. Introducción- 2. La problemática de las identidades – 3. El diálogo interreligioso como instrumento para la consecución de la convivencia pacífica y su promoción por el Estado -4. Diálogo interreligioso y gobernanza ciudadana. Interreligious dialogue and citizen governance ABSTRACT: The 21st century has been characterized by the emergence of identity issues. The invocation of identity in a globalized world is on the agenda of all research centers and has generated a huge intellectual and political debate. Many of the conflicts that plague the contemporary world are based on identity. Exclusionary identitarianism, whether of a religious, ethnic or nationalist nature, has taken root in many societies. They are, as the writer Amin Maalouf called them, the "killer identities", exclusionary identities based on two fundamental concepts: the conception of an identity as unique, all-embracing of the individual, and the thesis of the scapegoat. The fight against these initiatives is complex and requires different instruments. One of these instruments, in the case of radicalized religious identities, could be the promotion by the public authorities of interreligious dialogue. These initiatives would be inserted in the new concept of governance and Open Government, which encourages citizen participation in the development of public policies. The current research formulates a proposal for the application of interreligious dialogue at the municipal level as a mechanism to combat religious radicalization and exclusionary identitarianism in the search for more plural and peaceful societies

Gestión de la documentación

El objetivo de esta conferencia es dar una visión general de la gestión documental en los proyectos de telecomunicaciones, yendo más allá de su mera organización, para incluirla en la política general de información de la empresa y su cultura corporativa. Definición de conceptos básicos de: archivo, identificación y organización de tipos documentales en los proyectos telecomunicaciones, gestión documental y del conocimiento, inteligencia competitiva y aplicación de normas ISO.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Theoretical study of the electronic spectrum of p-benzoquinone

The electronic excited states of p-benzoquinone have been studied using multiconfigurational second-order perturbation theory (CASPT2) and extended atomic natural orbital (ANO) basis sets. The calculation of the singlet–singlet and singlet–triplet transition energies comprises 19 valence singlet excited states, 4 valence triplet states, and the singlet 3s,3p, and 3d members of the Rydberg series converging to the first four ionization limits. The computed vertical excitation energies are found to be in agreement with the available experimental data. Conclusive assignments to both valence and Rydberg states have been performed. The main features of the electronic spectrum correspond to the ππ∗ 1 1Ag→1 1B1u and ππ∗ 1 1Ag→3 1B1u transitions, computed to be at 5.15 and 7.08 eV, respectively. Assignments of the observed low-energy Rydberg bands have been proposed: An n→3p transition for the sharp absorption located at ca. 7.4 eV and two n→3d and π→3s transitions for the broad band observed at ca. 7.8 eV. The lowest triplet state is computed to be an nπ∗ 3B1g state, in agreement with the experimental [email protected] ; [email protected] ; [email protected]

Preocupación y conducta ecológica responsable en estudiantes universitarios: estudio comparativo entre estudiantes chilenos y españoles

ResumenSe discutirán los resultados de un estudio piloto, que forma parte de un proyecto mayor, orientado al análisis transcultural de la preocupación ambiental y su relación con la conducta ecológica. El propósito de este artículo es mostrar los resultados obtenidos de la aplicación del instrumento creado en España para probarlo en la realidad chilena, donde no se contaba con un instrumento pertinente que evaluara estos factores a nivel local. El método contempla la comparación de los resultados entre estudiantes chilenos (n=88) y españoles (n=149), a quienes se les aplica un cuestionario de conducta y preocupación ambiental. Los resultados indican diferencias entre ambos grupos, los cuales se analizan en función del modelo de conceptualización multidimensional de la preocupación por el medio ambiente manifestada en cuatro tipologías actitudinales: apático, antropocéntrico, conectado y afinidad emocional (Amérigo et al., 2012). Se considera, de igual forma, el papel importante de las variables culturales y psicosociales involucradas en los resultados. En las conclusiones se describe la importancia de contar con instrumentos que permitan iniciar estudios en el contexto chileno en el área, considerando los factores contextuales, como la agudización de la crisis ambiental en el país, la preocupación ciudadana sobre la situación y la necesidad de realizar estudios transculturales para seguir profundizando en el conocimiento de la temática a nivel mundial.AbstractAs part of a pilot study aimed at the transcultural analysis of environmental concern and its relationship with ecological behavior, a questionnaire assessing these was developed in Spain, and tested in Spain and in Chile. Chilean (n=88) and Spanish (n=149) students filled out the questionnaire. The results were analysed according to the model of multidimensional conceptualisation of concern for the environment manifested in 4 types of attitude: apathetic, anthropocentric, connected and emotional affinity (Amérigo et al., 2012). Results differed between the two groups, and cultural and psychosocial variables appear to play a significant role in this. This suggest that it is important to have instruments that facilitate environmental studies in the Chilean context, and to take contextual factors (such as the exacerbation of the country's environmental crisis and citizens’ concern about the situation) into account in such studies. Transcultural studies are key to deepening our understanding of the subject at the worldwide level