Rotating 5D-Kaluza-Klein Space-Times from Invariant Transformations

Using invariant transformations of the five-dimensional Kaluza-Klein (KK) field equations, we find a series of formulae to derive axial symmetric stationary exact solutions of the KK theory starting from static ones. The procedure presented in this work allows to derive new exact solutions up to very simple integrations. Among other results, we find exact rotating solutions containing magnetic monopoles, dipoles, quadripoles, etc., coupled to scalar and to gravitational multipole fields.Comment: 24 pages, latex, no figures. To appear in Gen. Rel. Grav., 32, (2000), in pres

Axisymmetric Stationary Solutions as Harmonic Maps

We present a method for generating exact solutions of Einstein equations in vacuum using harmonic maps, when the spacetime possesses two commutating Killing vectors. This method consists in writing the axisymmetric stationry Einstein equations in vacuum as a harmonic map which belongs to the group SL(2,R), and decomposing it in its harmonic "submaps". This method provides a natural classification of the solutions in classes (Weil's class, Lewis' class etc).Comment: 17 TeX pages, one table,( CINVESTAV- preprint 12/93

Oscillatons revisited

In this paper, we study some interesting properties of a spherically symmetric oscillating soliton star made of a real time-dependent scalar field which is called an oscillaton. The known final configuration of an oscillaton consists of a stationary stage in which the scalar field and the metric coefficients oscillate in time if the scalar potential is quadratic. The differential equations that arise in the simplest approximation, that of coherent scalar oscillations, are presented for a quadratic scalar potential. This allows us to take a closer look at the interesting properties of these oscillating objects. The leading terms of the solutions considering a quartic and a cosh scalar potentials are worked in the so called stationary limit procedure. This procedure reveals the form in which oscillatons and boson stars may be related and useful information about oscillatons is obtained from the known results of boson stars. Oscillatons could compete with boson stars as interesting astrophysical objects, since they would be predicted by scalar field dark matter models.Comment: 10 pages REVTeX, 10 eps figures. Updated files to match version published in Classical and Quantum Gravit

Avaliação dos efeitos de um protocolo com a plataforma NINTENDO WII® nas dimensões cognitivas e físicas /equilíbrio e coordenação) em idosos

Objetivos: Avaliar e quantificar o impacto do tratamento de fisioterapia, utilizando exclusivamente a Nintendo Wii®, na Qualidade de Vida relacionada com a saúde dos sujeitos com 65 anos ou mais e as mudanças na cognição, equilíbrio, coordenação e desempenho das Atividades da Vida Diária após o protocolo; Inquirir o grau de adesão ao treino. Material e Métodos: 30 sujeitos em dois momentos de avaliação. Medidas aplicadas: SF-12, MSE, TUG e com tarefa cognitiva, Escala de Equilíbrio de Berg, avaliação da coordenação e Escala de Barthel. Intervenção durante 4 semanas, 2 por semana, 60 minutos, em 8 sessões. Resultados: Ganhos em todas as escalas, com significado estatístico na Escala de Saúde Mental Geral, componente do SF-12 (p=0,008), MMSE (p=0,007), TUG normal (p=0,003), TUG com tarefa cognitiva (p=0,028) e Protocolo de Avaliação da Coordenação proposto por O’Neil et al. (p=0,008). Da amostra 46,67% teve um Baixo Grau de Adesão, 30% Médio Grau de Adesão, e 23,33% Alto Grau de Adesão. Conclusões: Um protocolo de intervenção de 4 semanas com a Nintendo Wii Sports® (bowling) em sujeitos institucionalizados, apresenta benefícios na QV relacionada com a Saúde Metal e de cognição, e dimensão física da coordenação e capacidade para a dupla-tarefa

Spherical Scalar Field Halo in Galaxies

We study a spherically symmetric fluctuation of scalar dark matter in the cosmos and show that it could be the dark matter in galaxies, provided that the scalar field has an exponential potential whose overall sign is negative and whose exponent is constrained observationally by the rotation velocities of galaxies. The local space-time of the fluctuation contains a three dimensional space-like hypersurface with surplus of angle.Comment: 5 REVTeX pages, no figures. Contains important suggestions provided by the referee. Final version, to appear in Phys. Rev.

Köhler disease: an infrequent or underdiagnosed cause of child's limping?

Köhler disease (KD) is the osteochondrosis of the tarsal navicular bone of the young children, which is a self-limited condition. Typically the child reports pain with mechanical characteristics in the medial region of the foot, however, intermittent or continuous limping may be the only clinical manifestation, which delays the diagnosis and consequently exposes to unnecessary tests and treatments. We describe a bilateral KD whose clinical manifestation was unilateral limping with 4 months evolution. The radiologic evaluation showed flattening, sclerosis and irregular rarefaction of both navicular bones. Claudication persisted for four weeks, after which, the child remains asymptomatic.info:eu-repo/semantics/publishedVersio

A new cosmological tracker solution for Quintessence

In this paper we propose a quintessence model with the potential $V(\Phi )=V_{o}[ \sinh {(\alpha \sqrt{\kappa_{o}}\Delta \Phi})] ^{\beta}$, which asymptotic behavior corresponds to an inverse power-law potential at early times and to an exponential one at late times. We demonstrate that this is a tracker solution and that it could have driven the Universe into its current inflationary stage. The exact solutions and the description for a complete evolution of the Universe are also given. We compare such model with the current cosmological observations.Comment: 13 pages REVTeX, 5 eps color figure

Scalar Field Dark Matter: head-on interaction between two structures

In this manuscript we track the evolution of a system consisting of two self-gravitating virialized objects made of a scalar field in the newtonian limit. The Schr\"odinger-Poisson system contains a potential with self-interaction of the Gross-Pitaevskii type for Bose Condensates. Our results indicate that solitonic behavior is allowed in the scalar field dark matter model when the total energy of the system is positive, that is, the two blobs pass through each other as should happen for solitons; on the other hand, there is a true collision of the two blobs when the total energy is negative.Comment: 8 revtex pages, 11 eps figures. v2 matches the published version. v2=v1+ref+minor_change