A Note on Supersymmetric WZW term in Four Dimensions

We reconsider the supersymmetric Wess-Zumino-Witten (SWZW) term in four dimensions. It has been known that the manifestly supersymmetric form of the SWZW term includes derivative terms on auxiliary fields, the highest components of chiral superfields, and then we cannot eliminate them by their equations of motion. We discuss a possibility for the elimination of such derivative terms by adding total derivative terms. Although the most of derivative terms can be eliminated as in this way, we find that all the derivative terms can be canceled, if and only if an anomalous term in SWZW term vanishes. As a byproduct, we find the first example of a higher derivative term free from such a problem.Comment: LaTeX, 10 pages, no figures, typos corrected, references added, accepted for publication in Modern Physics Letters

SDSS White Dwarf mass distribution at low effective temperatures

The DA white dwarfs in the Sloan Digital Sky Survey, as analyzed in the papers for Data Releases 1 and 4, show an increase in surface gravity towards lower effective temperatures below 11500 K. We study the various possible explanations of this effect, from a real increase of the masses to uncertainties or deficiencies of the atmospheric models. No definite answer is found but the tentative conclusion is that it is most likely the current description of convection in the framework of the mixing-length approximation, which leads to this effect.Comment: to appear in the proceedings of the 16th European Workshop on White Dwarfs, Barcelona, 200

Charged Particle Dynamics in the Field of a Slowly Rotating Compact Star

We study the dynamics of a charged particle in the field of a slowly rotating compact star in the gravitoelectromagnetic approximation to the geodesic equation . The star is assumed to be surrounded by an ideal, highly conducting plasma (taken as a magnetohydrodynamic fluid) with a stationary, axially symmetric electromagnetic field. The general relativistic Maxwell equations are solved to obtain the effects of the background spacetime on the electromagnetic field in the linearized Kerr spacetime. The equations of motion are then set up and solved numerically to incorporate the gravitational as well as the electromagnetic effects. The analysis shows that in the slow rotation approximation the frame dragging effects on the electromagnetic field are absent. However the particle is directly effected by the rotating gravitational source such that close to the star the gravitational and electromagnetic field produce contrary effects on the particle's trajectory.Comment: 10 pages, 6 figures in B & W PostScript Forma

Slow shocks and conduction fronts from Petschek reconnection of skewed magnetic fields: two-fluid effects

In models of fast magnetic reconnection, flux transfer occurs within a small portion of a current sheet triggering stored magnetic energy to be thermalized by shocks. When the initial current sheet separates magnetic fields which are not perfectly anti-parallel, i.e. they are skewed, magnetic energy is first converted to bulk kinetic energy and then thermalized in slow magnetosonic shocks. We show that the latter resemble parallel shocks or hydrodynamic shocks for all skew angles except those very near the anti-parallel limit. As for parallel shocks, the structures of reconnection-driven slow shocks are best studied using two-fluid equations in which ions and electrons have independent temperature. Time-dependent solutions of these equations can be used to predict and understand the shocks from reconnection of skewed magnetic fields. The results differ from those found using a single-fluid model such as magnetohydrodynamics. In the two-fluid model electrons are heated indirectly and thus carry a heat flux always well below the free-streaming limit. The viscous stress of the ions is, however, typically near the fluid-treatable limit. We find that for a wide range of skew angles and small plasma beta an electron conduction front extends ahead of the slow shock but remains within the outflow jet. In such cases conduction will play a more limited role in driving chromospheric evaporation than has been predicted based on single-fluid, anti-parallel models

Cool White Dwarfs Found in the UKIRT Infrared Deep Sky Survey

We present the results of a search for cool white dwarfs in the United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The UKIDSS LAS photometry was paired with the Sloan Digital Sky Survey (SDSS) to identify cool hydrogen-rich white dwarf candidates by their neutral optical colors and blue near-infrared colors, as well as faint Reduced Proper Motion magnitudes. Optical spectroscopy was obtained at Gemini Observatory, and showed the majority of the candidates to be newly identified cool degenerates, with a small number of G- to K-type (sub)dwarf contaminants. Our initial search of 280 deg2 of sky resulted in seven new white dwarfs with effective temperature T_eff ~ 6000 K. The current followup of 1400 deg2 of sky has produced thirteen new white dwarfs. Model fits to the photometry show that seven of the newly identified white dwarfs have 4120 K <= T_eff <= 4480 K, and cooling ages between 7.3 Gyr and 8.7 Gyr; they have 40 km/s <= v_tan <= 85 km/s and are likely to be thick disk 10-11 Gyr-old objects. The other half of the sample has 4610 K <= T_eff <= 5260 K, cooling ages between 4.3 Gyr and 6.9 Gyr, and 60 km/s <= v_tan <= 100 km/s. These are either thin disk remnants with unusually high velocities, or lower-mass remnants of thick disk or halo late-F or G stars.Comment: To appear in ApJ, accepted April 18 2011. 34 pages include 11 Figures and 5 Table

Oscillating p-Branes

Coset methods are used to construct the action describing the dynamics associated with the spontaneous breaking of the Poincare symmetries of D dimensional space-time due to the embedding of a p-brane with codimension N=D-p-1. The resulting world volume action is an ISO(1,p+N) invariant generalization of the Nambu-Goto action in d=p+1 dimensional space-time. Analogous results are obtained for an AdS p-brane with codimension N embedded in D dimensional AdS space, yielding an SO(2,p+N) invariant version of the Nambu-Goto action in d=p+1 dimensional space-time. Attention is focused on a supersymmetric extension of the D=6 Minkowski space case with an embedded p=3 brane; a particular realization of which is provided by a non-BPS vortex. Here both the Nambu-Goto-Akulov-Volkov action and its dual tensor form are presented.Comment: 25 pages, no figure

Amplification profiles of the SSR markers in cultivars of hexaploid wheat and their relatives

Dissertação de Mestrado em Psicologia das Organizações e do Trabalho, apresentada à Faculdade de Psicologia e de Ciências da Educação da Universidade de CoimbraEsta investigação insere-se na linha de investigação ligada à abordagem dos stakeholders e teve como principal objectivo estudar as relações existentes entre os padrões discursivos adoptados pela gestão (o discurso financeiro e económico, o discurso da responsabilidade social da empresa e o discurso dos stakeholders) e a saliência atribuída aos quatro tipos de stakeholders considerados neste estudo (sócios/accionistas, clientes, colaboradores e comunidade). Procurámos, ainda, analisar se determinadas características organizacionais e dos gestores influenciavam os seus discursos, e investigámos a possibilidade de haver um efeito moderador do Ciclo de Vida das Organizações (CVO) na relação entre os discursos adoptados pelos gestores e a saliência atribuída aos diferentes stakeholders organizacionais. Neste sentido, foi utilizada uma amostra de 111 gestores, provenientes de 50 empresas de várias dimensões e sectores, maioritariamente da zona centro do país, que responderam a três questionários: Questionário da Gestão de Stakeholders (GS) de Carvalho (2007); Questionário das Preocupações e Prioridades da Gestão de Carvalho (2007); e, Questionário do Ciclo de Vida Organizacional (CVO) de Carvalho (2001). Os resultados encontrados sugerem que, apesar de se verificarem algumas relações significativas entre estas três variáveis em estudo, não se verificou, tal como previsto, que a variável CVO moderasse a relação entre os discursos dos gestores e a saliência dos stakeholders. As implicações teóricas e práticas destes resultados serão alvo de análise e de discussão.This research falls in the line of research related to the stakeholder approach and had a main objective to study the relationship between the predominant speech patterns adopted by management (the financial and economic discourse, the discourse of corporate social responsibility and the discourse of stakeholders) and the salience attributed to four types of stakeholders considered in this study (partners / shareholders, clients, employees and community). We also tried to test whether certain organizational and managerial characteristics influenced their speeches, and investigated the possibility of a moderating effect of the CVO in the relationship between the organizational discourses adopted by managers and the salience attributed to the different stakeholders. In this sense, we used a sample of 111 managers, from 50 companies of various sizes and sectors, mostly in the center of the country who responded to three questionnaires: Questionnaire Stakeholder Management (GS) (Carvalho, 2007); Questionnaire Concerns and Priorities of Management (Carvalho, 2007); and Questionnaire Organizational Life Cycle (CVO) (Carvalho, 2001). The results suggest that, despite showing some significant relationships between these three variables studied, the variable CVO did not moderate the relationship between discourses of managers and stakeholders’ salience, as expected. The theoretical and practical implications of these results will be subject to analysis and discussion

Brane Vector Phenomenology

Local oscillations of the brane world are manifested as masssive vector fields. Their coupling to the Standard Model can be obtained using the method of nonlinear realizations of the spontaneously broken higher dimensional space-time symmetries, and to an extent, are model independent. Phenomenological limits on these vector field parameters are obtained using LEP collider data and dark matter constraints.Comment: 3 pages, 2 figures, late