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Search Results: 1 - 10 of 123477 matches for " T. Vargas "
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Ponzano-Regge Model on Manifold with Torsion
T Vargas
Physics , 2013,
Abstract: The connection between angular momentum in quantum mechanics and geometric objects is extended to manifold with torsion. First, we notice the relation between the $6j$ symbol and Regge's discrete version of the action functional of Euclidean three dimensional gravity with torsion, then consider the Ponzano and Regge asymptotic formula for the Wigner $6j$ symbol on this simplicial manifold with torsion. In this approach, a three dimensional manifold $M$ is decomposed into a collection of tetrahedra, and it is assumed that each tetrahedron is filled in with flat space and the torsion of $M$ is concentrated on the edges of the tetrahedron, the length of the edge is chosen to be proportional to the length of the angular momentum vector in semiclassical limit. The Einstein-Hilbert action is then a function of the angular momentum and the Burgers vector of dislocation, and it is given by summing the Regge action over all tetrahedra in $M$. We also discuss the asymptotic approximation of the partition function and their relation to the Feynmann path integral for simplicial manifold with torsion without cosmological constant.
El sentido de la vida en expolicías parapléjicos. Enfoque fenomenológico
Hector Téllez Vargas
Revista Latinoamericana de Psicología , 1991,
The energy of the universe in teleparallel gravity
T. Vargas Auccalla
Physics , 2003, DOI: 10.1023/B:GERG.0000022386.29438.be
Abstract: The teleparallel versions of the Einstein and the Landau-Lifshitz energy-momentum complexes of the gravitational field are obtained. By using these complexes, the total energy of the universe, which includes the energy of both the matter and the gravitational fields, is then obtained. It is shown that the total energy vanishes independently of both the curvature parameter and the three dimensionless coupling constants of teleparallel gravity.
The Energy of Bianchi Type I and II Universes in Teleparallel Gravity
Lau Loi So,T. Vargas
Physics , 2006,
Abstract: For certain models, the energy of the universe which includes the energy of both the matter and the gravitational fields is obtained by using the quasilocal energy-momentum in teleparallel gravity. It is shown that in the case of the Bianchi type I and II universes, not only the total energy but also the quasilocal energy-momentum for any region vanishes independently of the three dimensionless coupling constants of teleparallel gravity.
Regge Calculus in Teleparallel Gravity
J. G. Pereira,T. Vargas
Physics , 2002, DOI: 10.1088/0264-9381/19/19/301
Abstract: In the context of the teleparallel equivalent of general relativity, the Weitzenbock manifold is considered as the limit of a suitable sequence of discrete lattices composed of an increasing number of smaller an smaller simplices, where the interior of each simplex (Delaunay lattice) is assumed to be flat. The link lengths between any pair of vertices serve as independent variables, so that torsion turns out to be localized in the two dimensional hypersurfaces (dislocation triangle, or hinge) of the lattice. Assuming that a vector undergoes a dislocation in relation to its initial position as it is parallel transported along the perimeter of the dual lattice (Voronoi polygon), we obtain the discrete analogue of the teleparallel action, as well as the corresponding simplicial vacuum field equations.
Goedel type solution in teleparallel gravity
Yu. N. Obukhov,T. Vargas
Physics , 2004, DOI: 10.1016/j.physleta.2004.06.003
Abstract: The stationary cosmological model without closed timelike curves of G\"odel type is obtained for the ideal dust matter source within the framework of the teleparallel gravity. For a specific choice of the teleparallel gravity parameters, this solution reproduces the causality violating stationary G\"odel solution in general relativity, in accordance with the teleparallel equivalent of general relativity. The relation between the axial-vector torsion and the cosmic vorticity is clarified.
A mathematical Model to Predict Transition-to-Fatigue During Isometric Exercise on Muscles of the Lower Extremities  [PDF]
Jorge Garza-Ulloa, Huiying Yu, T. Sarkodie- Gyan, Pablo Rangel, Olatunde Adeoye, Noe Vargas Hernandez
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.410B005

Surface Electromyography (sEMG) activities of the four muscles were studied from twelve healthy subjects to analyze muscle fatigue. Data were recorded while subjects performed isometric exercises for a period of time until fatigue. The signal was segmented with 5000 samples to enable the evolutionary process. Based on the mean power spectrum and Median Frequency (MDF) of each segment, we developed a methodology that is able to detect the signal into a meaningful sequence of Non-Fatigue to Transition-to-Fatigue. By identifying this transitional fatigue stage, it is possible to predict when fatigue will occur, which provides the foundation of the automated system that has the potential to aid in many applications of our lives, including sports, rehabilitation and ergonomics.

Progresividad del gasto público en salud en México: 1984-2002
Vargas-Téllez, César Octavio;
Economía, sociedad y territorio , 2011,
Abstract: this study attempts to calculate the progressivity of health expenditure by institution, type of medical care and its behavior for 16 years. using analysis of incidence and micro data, we generated distributions of transfers of public expenditure on health per family. the analysis is completed with the calculation of inequality indexes; the results show a gradual improvement in the progressivity of health expenditure in the study period, with higher progressivity of health services provided by the secretariat of health and fewer improvements in issste and pemex services. by type of medical care, preventive services seem more progressive than curative and hospital services. the results support the hypothesis that universal health care and their unification through a single entity would substantially improve the fairness of the public health system in mexico.
?Es redistributivo el sistema fiscal en México? La experiencia de 1984-2002
Vargas Téllez, César Octavio;
Estudios sociales (Hermosillo, Son.) , 2010,
Abstract: this paper has calculated the mexican family tax burden for every kind of taxes. the period studied take account almost twenty years, from 1984 to 2002 which cover the structural change suffered by the mexican economy. the approach was based on micro-data, basically the national house-hold surveys (enigh). since, there are not continue surveys about mexican families, were employed four years (1984, 1989, 1996 and 2002) to capture a dynamic behavior. as well, were calculated the progressivity degree for every kind of taxes, through inequality indexes such concentration and kakwani. by other side the tax redistributive impact was estimated applying reynolds-smolensky index. in accordance with the results the whole tax system is lightly progressive, almost neutral; where such proggresivity is found exclusively on the personnel income. disaggregating, the direct taxes registered certain progressivity while the indirect taxes were significative regressive. finally was simulated an increase for the vat rate with two possible scenarios, the fist one with a reduced tax of 6% for food and medicines, and the second one, with a general rate of 10%. the result, cast a vat system 50% less progressive, and a bigger burden tax for low income families, with only a 26% more collected.
Progresividad del gasto público en salud en México: 1984-2002
César Octavio Vargas-Téllez
Economía, sociedad y territorio , 2011,
Abstract: En este trabajo intentamos calcular la progresividad que tiene el gasto en salud por institución, tipo de cuidados médicos y su evolución a lo largo de 16 a os. Utilizando análisis de incidencia y microdatos, se generaron distribuciones de las transferencias del gasto público en salud por familia. El análisis se completa con el cálculo de índices de desigualdad, los resultados arrojan una paulatina mejoría en la progresividad del gasto en salud en el tiempo de estudio, con mayor progresividad de los servicios de salud prestados por la Secretaría de Salud y menores avances en los servicios del ISSSTE y Pemex. Por tipo de cuidados médicos, los servicios preventivos se han desarrollado más que los servicios hospitalarios y curativos. Los resultados sostienen la hipótesis de que la universalización de los servicios de salud y su unificación en una sola entidad proveedora mejoraría sustancialmente la equidad del sistema de salud pública en México.
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