An infinite family of magnetized Morgan-Morgan relativistic thin disks

Applying the Horsk\'y-Mitskievitch conjecture to the empty space solutions of Morgan and Morgan due to the gravitational field of a finite disk, we have obtained the corresponding solutions of the Einstein-Maxwell equations. The resulting expressions are simply written in terms of oblate spheroidal coordinates and the solutions represent fields due to magnetized static thin disk of finite extension. Now, although the solutions are not asymptotically flat, the masses of the disks are finite and the energy-momentum tensor agrees with the energy conditions. Furthermore, the magnetic field and the circular velocity show an acceptable physical behavior.Comment: Submitted to IJTP. This paper is a revised and extended version of a paper that was presented at arXiv:1006.203

Megaprojetos de infraestrutura territorial em face da vulnerabilidade urbana regional-sub-Regional. O Caso do Departamento de Antioquia

The main objective of this paper is to address the impact of mega infrastructure projects on the planning and management of the territory in accordance with its vulnerability. As a methodology, it describes, from the point of view of social transaction costs, the infrastructure, order and territorial planning, which allow to orientate the components that are required so that the mega-projects cohere the diffuse conditions derived from the physical space of the territory. As main contributions, the management of mega-projects from the point of view of territorial ordering, planning and ecological dependence, must pass to the scenario of the applied and masterly chair, through the research and proposal foundation as a line of work.El escrito tiene como principal objetivo el abordaje de la incidencia de los megaproyectos de infraestructura en el ordenamiento y la planeación conforme a la vulnerabilidad territorial. Como metodología, describe desde la óptica de los costos sociales de transacción, la infraestructura, ordenamiento y planeación territorial, que permiten orientar los componentes que se requieren para que los megaproyectos cohesionen las condiciones difusas derivadas de lo físico espacial del territorio. Como principales aportes resalta la gestión de los megaproyectos desde el ordenamiento, la planeación y la dependencia ecológica territorial, deben pasar al escenario de la cátedra aplicada y magistral, a través, de la fundamentación investigativa y propositiva como línea de trabajo.L'objectif principal de ce document est d'aborder l'impact des mégaprojets d'infrastructure sur la planification et la gestion en fonction de la vulnérabilité du territoire. En tant que méthodologie, elle décrit, sous l'angle des coûts de transaction sociaux, les infrastructures, la planification et l'aménagement du territoire, qui permettent d'orienter les composantes nécessaires aux mégaprojets pour mettre en cohérence les conditions diffuses issues de l'espace physique du territoire. Comme contributions principales, la gestion des méga-projets du point de vue de l'ordonnancement territorial, de la planification et de la dépendance écologique, doit passer au scénario de la chaire appliquée et magistrale, à travers la fondation de recherche et de proposition comme ligne de travail.Oprincipal objetivo deste trabalho é abordar o impacto dos megaprojetos de infra-estrutura no planejamento e gestão de acordo com a vulnerabilidade territorial. Como metodologia, descreve, do ponto de vista dos custos de transação social, infra-estrutura, planejamento e ordenação territorial, que permitem orientar os componentes necessários para que os megaprojetos coexistam as condições difusas derivadas do espaço físico do território. Como principais contribuições, a gestão de megaprojetos do ponto de vista da ordenação territorial, planejamento e dependência ecológica, deve passar para o cenário da cadeira aplicada e magistral, através da pesquisa e da fundamentação da proposta como uma linha de trabalho

The AdS(4) x CP(3) string and its Bethe equations in the near plane wave limit

We perform a detailed study of bosonic type IIA string theory in a large light-cone momentum / near plane wave limit of $AdS_4 \times CP_3$. In order to attain this we derive the Hamiltonian up to cubic and quartic order in number of fields and calculate the energies for string excitations in a $R\times S^2 \times S^2$ subspace. The computation for the string energies is performed for arbitrary length excitations utilizing an unitary transformation which allows us to remove the cubic terms in the Hamiltonian. We then rewrite a recent set of proposed all loop Bethe equations in a light-cone language and compare their predictions with the obtained string energies. We find perfect agreement.Comment: 28 pages, references and footnote adde

Exceptional Askey-Wilson type polynomials through Darboux-Crum transformations

An alternative derivation is presented of the infinitely many exceptional Wilson and Askey-Wilson polynomials, which were introduced by the present authors in 2009. Darboux-Crum transformations intertwining the discrete quantum mechanical systems of the original and the exceptional polynomials play an important role. Infinitely many continuous Hahn polynomials are derived in the same manner. The present method provides a simple proof of the shape invariance of these systems as in the corresponding cases of the exceptional Laguerre and Jacobi polynomials.Comment: 24 pages. Comments and references added. To appear in J.Phys.

CMB anisotropy predictions for a model of double inflation

We consider a double-inflationary model with two massive scalar fields interacting only gravitationally in the context of a flat cold dark matter (CDM) Universe. The cosmic microwave background (CMB) temperature anisotropies produced in this theory are investigated in great details for a window of parameters where the density fluctuation power spectrum P(k) is in good agreement with observations. The first Doppler (``acoustic'') peak is a crucial test for this model as well as for other models. For the ``standard'' values of the cosmological parameters of CDM, our model is excluded if the height of the Doppler peak is sensibly higher than about three times the Sachs-Wolfe plateau.Comment: 12 pages LaTeX using revtex, to be published in Phys. Rev.

The variable phase method used to calculate and correct scattering lengths

It is shown that the scattering length can be obtained by solving a Riccati equation derived from variable phase theory. Two methods of solving it are presented. The equation is used to predict how long-range interactions influence the scattering length, and upper and lower bounds on the scattering length are determined. The predictions are compared with others and it is shown how they may be obtained from secular perturbation theory.Comment: 7 pages including 3 figure

On the radioecological issues of natural radionuclides in water and sediment of a highly contaminated lagoon from Mexico

Se han determinado las concentraciones de actividad de radionucleidos naturales en el agua y los sedimentos de la laguna El Pedernalillo, Zacatecas, México

Engaging with issues of emotionality in mathematics teacher education for social justice

This article focuses on the relationship between social justice, emotionality and mathematics teaching in the context of the education of prospective teachers of mathematics. A relational approach to social justice calls for giving attention to enacting socially-just relationships in mathematics classrooms. Emotionality and social justice in teaching mathematics variously intersect, interrelate or interweave. An intervention, usng creative action methods, with a cohort of prospective teachers addressing these issues is described to illustrate the connection between emotionality and social justice in the context of mathematics teacher education. Creative action methods involve a variety of dramatic, interactive and experiential tools that can promote personal and group engagement and embodied reflection. The intervention aimed to engage the prospective teachers with some key issues for social justice in mathematics education through dialogue about the emotionality of teaching and learning mathematics. Some of the possibilities and limits of using such methods are considered