Unimodular cosmology and the weight of energy

Some models are presented in which the strength of the gravitational coupling of the potential energy relative to the same coupling for the kinetic energy is, in a precise sense, adjustable. The gauge symmetry of these models consists of those coordinate changes with unit jacobian.Comment: LaTeX, 23 pages, conclusions expanded. Two paragraphs and a new reference adde

Developing communication and thinking skills in English as a Foreign Language Education undergraduate students: a proposal for a syllabus model

It is our aim to share a proposal for a new syllabus model and learner-centered methodology for English as a Foreign Language students in the Degree in Teaching in Primary Education at the Universidad de Zaragoza (Spain), presenting the theoretical tenets and analyzing samples of resources and materials that have been designed. In a context of great diversity of levels and learning profiles in the abovementioned educational setting, it is no longer valid to conceive this part of teacher training only in terms of language proficiency, but rather it is necessary to equip students with learning to learn tools and metacognitive strategies as well as materials and resources purposefully designed bearing in mind their context, professional interests and linguistic needs. As a result, throughout the three 6 ECTS courses in the Degree (English in Primary Education I, II and III, for ist, 2nd and 4th year students respectively) we seek to implement active methodologies and make use of a variety of resources following Communicative Language Teaching and Task-based Instruction principles, such as the following: (i) Deep Learning (Clark, 2009a, 2009b) and Scaffolded, Visible Thinking (Ritchhart, Church, and Morrison, 2011); (ii) Cooperative Learning (Kagan and Kagan, 1994); (iii) ICTs and EdTech; (iv) reflective learning, promoting self-assessment and peer-assessment, and (v) Project Based Learning (BIE, 2003). Overall, the teaching proposal designed has enabled us to partially respond to heterogeneity in our large classes and make our students'' learning of a language relevant and meaningful

Supersymmetric solutions of gauged five-dimensional supergravity with general matter couplings

We perform the characterization program for the supersymmetric configurations and solutions of the $\mathcal{N}=1$, $d=5$ Supergravity Theory coupled to an arbitrary number of vectors, tensors and hypermultiplets and with general non-Abelian gaugins. By using the conditions yielded by the characterization program, new exact supersymmetric solutions are found in the $SO(4,1)/SO(4)$ model for the hyperscalars and with $SU(2)\times U(1)$ as the gauge group. The solutions also content non-trivial vector and massive tensor fields, the latter being charged under the U(1) sector of the gauge group and with selfdual spatial components. These solutions are black holes with $AdS_2 \times S^3$ near horizon geometry in the gauged version of the theory and for the ungauged case we found naked singularities. We also analyze supersymmetric solutions with only the scalars $\phi^x$ of the vector/tensor multiplets and the metric as the non-trivial fields. We find that only in the null class the scalars $\phi^x$ can be non-constant and for the case of constant $\phi^x$ we refine the classification in terms of the contributions to the scalar potential.Comment: Minor changes in wording and some typos corrected. Version to appear in Class. Quantum Grav. 38 page

Relationship of indicators of ability and experience of military sports skydiving with the psychological state and performance in competition of elite jumpers

© 2018: Servicio de Publicaciones de la Universidad de Murcia. This document is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in Cuadernos de Psicología del Deporte.Se deben considerar múltiples variables cuando se habla de rendimiento deportivo. Entre ellas, la literatura establece la importancia de la psicología y las técnicas indicadoras de la experiencia adquirida en la disciplina. Este estudio pretende establecer la relación entre determinados constructos que definen el perfil psicológico del deportista con indicadores de habilidad en paracaidismo militar. Para ello, se encuestó a 42 saltadores de 40,86 años (±7,35) pertenecientes al ejército español y a la guardia civil durante la celebración del Campeonato Nacional Militar de paracaidismo que se celebra anualmente, para conocer su nivel de optimismo, resiliencia, bienestar psicológico y burnout. Se concluye que los años de experiencia en paracaidismo y el número de saltos, como indicadores de habilidad, deben ser tomados en cuenta con un mayor nivel de concreción y especificidad, ya que ciertas variables psicológicas pueden aumentar o disminuir dependiendo de ellas. Conviene estudiar cada caso en particular para comprender qué puede ocurrir en el estado del paracaidista y desarrollar estrategias para optimizar el rendimiento deportivo.Multiple variables must be considered when talking about sports performance. Among them, the literature estblishes the importance of psychology and indicator techniques of experience acquired in the discipline. This study aims to establish the relationship between certain constructs that define the psychological profile of the athlete with skill indicators in military parachuting. For this, 42 jumpers aged 40.86 years old (±7.35) belonging to the Spanish army and the civil guard during the celebration of the National Military Championship of Skydiving which is held annually surveyed to know their level of optimism, resilience, psychological well-being, and burnout. It is concluded that the years of skydiving experience and the number of jumps, as indicators of skill, must be taken into account with a higher level of concreteness and specificity since certain psychological variables can increase or decrease depending on them. It is convenient to study each case, in particular, to understand what can happen in the state of the parachutist and develop strategies for optimizing sports performance.Múltiplas variáveis devem ser consideradas quando se fala em desempenho desportivo. Eentre eles, a literatura estabelece a importância da psicologia e das técnicas indicadoras da experiência adquirida na disciplina. Este estudo visa estabelecer a relação entre determinados constructos que definem o perfil psicológico do atleta com indicadores de habilidade no paraquedismo militar. Para tal, foram inquiridos 42 saltadores com 40,86 anos (±7,35) pertencentes ao exército espanhol e à guarda civil durante a celebração do Campeonato Nacional Militar de paraquedismo que se realiza anualmente para conhecer o seu nível de optimismo, resiliência, bem-estar psicológico e esgotamento. Conclui-se que os anos de experiência em paraquedismo e o número de saltos, como indicadores de habilidade, devem ser levados em consideração com maior grau de especificidade, pois certas variáveis psicológicas podem aumentar ou diminuir. É conveniente estudar cada caso em articular para entender o que pode acontecer no estado do paraquedista e desenvolver estratégias para otimizar o desempenho esportivo

Stationary strings and branes in the higher-dimensional Kerr-NUT-(A)dS spacetimes

We demonstrate complete integrability of the Nambu-Goto equations for a stationary string in the general Kerr-NUT-(A)dS spacetime describing the higher-dimensional rotating black hole. The stationary string in D dimensions is generated by a 1-parameter family of Killing trajectories and the problem of finding a string configuration reduces to a problem of finding a geodesic line in an effective (D-1)-dimensional space. Resulting integrability of this geodesic problem is connected with the existence of hidden symmetries which are inherited from the black hole background. In a spacetime with p mutually commuting Killing vectors it is possible to introduce a concept of a $\xi$-brane, that is a p-brane with the worldvolume generated by these fields and a 1-dimensional curve. We discuss integrability of such $\xi$-branes in the Kerr-NUT-(A)dS spacetime.Comment: 8 pages, no figure

On the Bogomol'nyi bound in Einstein-Maxwell-dilaton gravity

It has been shown that the 4-dimensional Einstein-Maxwell-dilaton theory allows a Bogomol'nyi-type inequality for an arbitrary dilaton coupling constant $\alpha$, and that the bound is saturated if and only if the (asymptotically flat) spacetime admits a nontrivial spinor satisfying the gravitino and the dilatino Killing spinor equations. The present paper revisits this issue and argues that the dilatino equation fails to ensure the dilaton field equation unless the solution is purely electric/magnetic, or the dilaton coupling constant is given by $\alpha=0, \sqrt 3$, corresponding to the Brans-Dicke-Maxwell theory and the Kaluza-Klein reduction of 5-dimensional vacuum gravity, respectively. A systematic classification of the supersymmetric solutions reveals that the solution can be rotating if and only if the solution is dyonic or the coupling constant is given by $\alpha=0, \sqrt 3$. This implies that the theory with $\alpha \ne 0, \sqrt 3$ cannot be embedded into supergravity except for the static truncation. Physical properties of supersymmetric solutions are explored from various points of view.Comment: v2: 23 pages, typos corrected, minor modifications, to appear in CQ

Functional Integration Approach to Hysteresis

A general formulation of scalar hysteresis is proposed. This formulation is based on two steps. First, a generating function g(x) is associated with an individual system, and a hysteresis evolution operator is defined by an appropriate envelope construction applied to g(x), inspired by the overdamped dynamics of systems evolving in multistable free energy landscapes. Second, the average hysteresis response of an ensemble of such systems is expressed as a functional integral over the space G of all admissible generating functions, under the assumption that an appropriate measure m has been introduced in G. The consequences of the formulation are analyzed in detail in the case where the measure m is generated by a continuous, Markovian stochastic process. The calculation of the hysteresis properties of the ensemble is reduced to the solution of the level-crossing problem for the stochastic process. In particular, it is shown that, when the process is translationally invariant (homogeneous), the ensuing hysteresis properties can be exactly described by the Preisach model of hysteresis, and the associated Preisach distribution is expressed in closed analytic form in terms of the drift and diffusion parameters of the Markovian process. Possible applications of the formulation are suggested, concerning the interpretation of magnetic hysteresis due to domain wall motion in quenched-in disorder, and the interpretation of critical state models of superconducting hysteresis.Comment: 36 pages, 9 figures, to be published on Phys. Rev.