Generalization of the Hamilton-Jacobi approach for higher-order singular systems

We generalize the Hamilton-Jacobi formulation for higher-order singular systems and obtain the equations of motion as total differential equations. To do this we first study the constraints structure present in such systems.

Conformal field theory of AdS background with Ramond-Ramond flux

We review a formalism of superstring quantization with manifest six-dimensional spacetime supersymmetry, and apply it to AdS(3) x S-3 backgrounds with Ramond-Ramond flux. The resulting description is a conformal field theory based on a sigma model whose target space is a certain supergroup SU' (2\2).

Light deflection and quadratic gravity

We study the bending of light caused by a static gravitational field generated by a localized material source in the context of quadratic gravity. Our calculation shows that for light rays passing close to the Sun the deflection Phi lies in the interval 0 < < 1.75. A tree-level approach to the same issue tells us that the vacuum concerning quadratic gravity is a dispersive medium. Nom Phi is energy dependent and ranges from 0(+) to 1.75(-) arcsec.

Mass neutrino flavor evolution in spacetime with torsion

In the framework of the spacetime with torsion, we obtain the flavor evolution equation of the mass neutrino oscillation in vacuum. A comparison with the result of general relativity case shows that the flavor evolutionary equations in Riemann spacetime and Weitzenbock spacetimes are equivalent in the spherical symmetric Schwarzschild spacetime, but turn out to be different in the case of the axial symmetry.

Manifestly covariant actions for D=4 self-dual Yang-Mills and D=10 super-Yang-Mills

Using an infinite number of fields, we construct actions for D = 4 self-dual Yang-Mills with manifest Lorentz invariance and for D = 10 super-Yang-Mills with manifest super-Poincare invariance. These actions are generalizations of the covariant action for the D = 2 chiral boson which was first studied by McClain, Wu, Yu and Wotzasek.

Pseudoclassical mechanics for the spin-0 and -1 particles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Programa de apoio a cuidadores: uma ação terapêutica e preventiva na atenção à saúde dos idosos

Dans le cadre du service de gériatrie du Centre de Santé-école de la faculté de médecine de Botucatu (Université de São Paulo), a été établi un programme d'appui à ces soignants avec les objectifs suivants: préserver leur qualité de vie et favoriser de meilleures conditions familiales aux patients. Le programme comprend de 10 à 12 réunions par semaine, de deux heures de durée, coordonnées par deux psychologues. on utilise des techniques de psychodrame centrées sur le rôle du soignant et leurs conséquences sociales et émotionnelles. Les informations théoriques sont transmises au moyen de discussions de groupe et de moyens audiovisuels. Les thèmes suivants sont abordés : signification et motivation du soin donné, signaux d'alertes de fatigue physique et mentale du soignant, les possibilités de se traiter et de demander de l'aide, une méthode d'amélioration de la communication face à une déficience visuelle, auditive et cognitive, une méthode pour favoriser l'indépendance et l'autonomie et surmonter les problèmes relatifs à l'hygiène, la mobilité, l'agression, l'irritation, les hallucinations et les idées délirantes de la personne âgée. Au cours de la première réunion de chaque groupe (qui comprend de 10 à 20 participants) on applique une échelle d'évaluation de l'impact émotionnel sur les soignants (Zarit et al., 1980) et le SRQ (Self Report Questionnaire - Mari and Williams, 1986) qui identifient des désordres psychiatriques. Ces échelles sont reproduites à la fin du programme, pour observer d'éventuelles modifications. Les données obtenues indiquent des changements favorables dans l'expression d'émotions, l'établissement de limites et de retour à des activités de loisirs.

Reflux esophagitis in chagasic megaesophagus

The esophagitis associated with chagasic megaesophagus is commonly attributed to food and secretion stasis, thereby its name of stasis esophagitis. The present work suggests instead that in some chagasic patients the clinical, endoscopic and histological findings are more compatible with a true reflux esophagitis.

Morphologic changes in the vesical transition epithelium of alcoholic rats

Few studies are available about the effect of alcohol on the epithelium of the urinary bladder. In the present investigation we studied the ultrastructure of the vesical transition epithelium of normal rats and of rats submitted to experimental chronic alcoholism. Adult rats were submitted to experimental chronic alcoholism by the ingestion of sugar cane liquor. The vesical epithelium was examined after 60, 120, 180 and 240 days of alcohol treatment by transmission electron microscopy. Surface cells presented nuclear and cytoplasmic changes and marked cellular desquamation. There was an increase in multivesicular bodies and lysosomes suggesting cell degeneration. Mast cell infiltration was observed, possibly related to increased epithelial sensitivity. Intercellular spaces were frequently observed. The transition epithelium of the urinary bladder was found to be sensitive to the action of alcohol, as demonstrated by the changes in the components of the blood-urine barrier, the greater sensitivity to inflammation, the increase in cell desquamation and the greater recycling of the apical membrane and of the fusiform vesicles of surface cells observed in alcoholic rats.

A CLUSTER MODEL FOR HYBRIDS

A model for describing hybrid spectroscopy similar to the diquark model for baryons is presented. Mass and r.m.s. radii are calculated and compared with experimental results.

Podolsky's higher-order electromagnetism from first principles

Podolsky's higher-order field equations are obtained by generalizing the laws of Podolsky's electrostatics, which follow from Coulomb's generalized law and superposition, to be consistent with special relativity. In addition, it is necessary to take into account the independence of the observed charge of a particle on its speed. It is also shown that the gauge-independent term concerning the Feynman propagator for Podolsky's generalized electrodynamics has a good ultraviolet behaviour at the expense of a negative metric massive ghost which, contrary to what is currently assumed in the literature, is non-tachyonic. A brief discussion on Podolsky's characteristic length is presented as well.

DIRAC CONFINEMENT BY A VARIATIONAL APPROACH

An analytical approximate method for the Dirac equation with confining power law scalar plus vector potentials, applicable to the problem of the relativistic quark confinement, is presented. The method consists in an improved version of a saddle-point variational approach and it is applied to the fundamental state of massless single quarks for some especial cases of physical interest. Our treatment emphasizes aspects such as the quantum-mechanical relativistic Virial theorem, the saddle-point character of the critical point of the expectation value of the total energy, as well as the Klein paradox and the behaviour of the saddle-point variational energies and wave functions.

Relaxation and tunnelling of structural units within the LTO phase of La2CuO4

The anelastic relaxation (elastic energy loss and Young modulus) of nearly stoichiometric La2CuO4+delta with LTO structure was measured. Extraordinarily intense effects are present below room temperature in the elastic dynamic susceptibility, indicating relaxational dynamics of a relevant fraction of the lattice. The involved degrees of freedom are identified as rotations of the CuO6 octahedra. Two distinct processes are found at frequencies around 1 kKz: one is observed around 150 K and is characterized by a mean activation energy of 2800 K; the second one occurs below 30 K and is governed by atomic tunnelling. Two explanations are proposed for the faster process: i) formation of fluctuating LTT domains on a scale of few atomic cells; ii) the LTO phase is a dynamical Jahn-Teller phase with all the octahedra tunneling between two LTT-like tilts. In both cases there would be important implications regarding the mechanisms giving rise to charge nanophase separation and strong electron-phonon coupling.