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Search Results: 1 - 10 of 327060 matches for " S. Estrada "
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Víctimas de un experimento: Conflicto multicultural en el programa de oportunidades
Carlos Andrés Estrada
Revista de Estudios Sociales , 1998,
Abstract:
Rese a de "Problemas antropológicos y utópicos del conocimiento" de Hugo Zemelman
Julio Estrada Cortés
Nueva antropología , 1996,
Abstract:
Editorial
Jesús Arroyo Estrada
Contaduría y administración , 2007,
Abstract:
Cartesian modules in small categories
E. Enochs,S. Estrada
Mathematics , 2012,
Abstract: In this note we extend the main results of [E. Enochs and S. Estrada, Relative homological algebra in the category of quasi-coherent sheaves. Adv. in Math. 194(2005), 284-295] to the category of cartesian modules over a flat presheaf of rings and on an arbitrary small category. This provides with new applications of that paper to the categories of quasi-coherent sheaves on an Artin stack or on a Deligne-Mumford stack.
Effect of Changes in Body Weight, Body Condition and Back Fat During Last Month of Pregnancy on the Reproductive Efficiency of Bos indicus Cows in the Tropics of Costa Rica  [PDF]
Jaime Galindo, Carlos S. Galina, Sandra Estrada, Juan José Romero
Open Journal of Veterinary Medicine (OJVM) , 2013, DOI: 10.4236/ojvm.2013.31005
Abstract:

With the aim of evaluating how changes in the metabolic status in the last month of pregnancy affects reproductive efficiency, forty six Bos indicus multiparous cows (5.5 ± 2.4 parturitions), were used. Measurements of body weight (BW), body condition score (BCS) and dorsal back fat (BF) were taken in the last month of pregnancy, postpartum period previous to synchronization (average 50 d) and at breeding by natural mating following synchronization with a progestin (average 70 d). Average postpartum days to resumption to ovarian activity were 79.96 ± 16.5 d, and average postpartum days to conception was 88.5 ± 14 d. Days postpartum to resumption of the ovarian activity was positively correlated (0.51, P < 0.01) with days postpartum to conception, also, days postpartum to conception was positively correlated with prepartum back fat (14 d before parturition) (0.44, P < 0.05). It was observed that BF at calving which is an objective measurement had a low correlation with other productive variables such as BCS and BW (always less than 0.39). Body fat might be a more reliable indicator of the current metabolic status of the animal particularly in the last month of pregnancy when the indicators of BCS are somehow more difficult to interpret and subjective.

Distributional asymptotic expansions of spectral functions and of the associated Green kernels
R. Estrada,S. A. Fulling
Electronic Journal of Differential Equations , 1999,
Abstract: Asymptotic expansions of Green functions and spectral densities associated with partial differential operators are widely applied in quantum field theory and elsewhere. The mathematical properties of these expansions can be clarified and more precisely determined by means of tools from distribution theory and summability theory. (These are the same, insofar as recently the classic Cesaro--Riesz theory of summability of series and integrals has been given a distributional interpretation.) When applied to the spectral analysis of Green functions (which are then to be expanded as series in a parameter, usually the time),these methods show: (1) The ``local'' or ``global'' dependence of the expansion coefficients on the background geometry, etc., is determined by the regularity of the asymptotic expansion of the integrand at the origin (in ``frequency space''); this marks the difference between a heat kernel and a Wightman two-point function, for instance. (2) The behavior of the integrand at infinity determines whether the expansion of the Green function is genuinely asymptotic in the literal, pointwise sense, or is merely valid in a distributional (Cesaro-averaged) sense; this is the difference between the heat kernel and the Schrodinger kernel. (3) The high-frequency expansion of the spectral density itself is local in a distributional sense (but not pointwise). These observations make rigorous sense out of calculations in the physics literature that are sometimes dismissed as merely formal.
Distributional Asymptotic Expansions of Spectral Functions and of the Associated Green Kernels
R. Estrada,S. A. Fulling
Physics , 1997,
Abstract: Asymptotic expansions of Green functions and spectral densities associated with partial differential operators are widely applied in quantum field theory and elsewhere. The mathematical properties of these expansions can be clarified and more precisely determined by means of tools from distribution theory and summability theory. (These are the same, insofar as recently the classic Cesaro-Riesz theory of summability of series and integrals has been given a distributional interpretation.) When applied to the spectral analysis of Green functions (which are then to be expanded as series in a parameter, usually the time), these methods show: (1) The "local" or "global" dependence of the expansion coefficients on the background geometry, etc., is determined by the regularity of the asymptotic expansion of the integrand at the origin (in "frequency space"); this marks the difference between a heat kernel and a Wightman two-point function, for instance. (2) The behavior of the integrand at infinity determines whether the expansion of the Green function is genuinely asymptotic in the literal, pointwise sense, or is merely valid in a distributional (cesaro-averaged) sense; this is the difference between the heat kernel and the Schrodinger kernel. (3) The high-frequency expansion of the spectral density itself is local in a distributional sense (but not pointwise). These observations make rigorous sense out of calculations in the physics literature that are sometimes dismissed as merely formal.
Transfinite tree quivers and their representations
E. Enochs,S. Estrada,S. ?zdemir
Mathematics , 2012,
Abstract: The idea of "vertex at the infinity" naturally appears when studying indecomposable injective representations of tree quivers. In this paper we formalize this behavior and find the structure of all the indecomposable injective representations of a tree quiver of size an arbitrary cardinal $\kappa$. As a consequence the structure of injective representations of noetherian $\kappa$-trees is completely determined. In the second part we will consider the problem whether arbitrary trees are source injective representation quivers or not.
The frequency of intestinal parasites in puppies from Mexican kennels  [PDF]
Enedina Jiménez-Cardoso, Leticia Eligio-García, Adrián Cortés-Campos, Apolinar Cano Estrada, Margarita Pinto-Sagahón, Cynthia Noguera-Estrada
Health (Health) , 2010, DOI: 10.4236/health.2010.211196
Abstract: The purpose of this investigation was to determine the intestinal parasite prevalence in puppies from six different kennels; four kennels were in Guadalajara and Zapopan cities (Jalisco State) and two kennels were in Mexico City. From October 2006 to November 2007, we collected 441 fecal samples from 147 puppies, both male and female, ranging from 1 to 36 months of age. Three samples from every puppy were analyzed by using the Faust technique. The prevalence found were as follows: Giardia intestinalis (genotype A and B) 6.8%; Cystoisospora 21.08%; Uncinaria 7.48%; Toxocara canis 12.29% and multiparasitism (Giardia, Toxocara and Uncinaria) 4.76%. The highest prevalence for both Giardia and Cystoisospora were found in 2-3- month-old puppies; the highest prevalence for Toxocara canis was found in 3-4-month-old puppies. In the kennels of Mexico City we found mainly Giardia intestinalis, Cystoisospora to be most prevalent in Zapopan and Toxocara canis in Guadalajara. The high prevalence of intestinal parasites found in this study demonstrates an increased risk for infection in humans, as these animals are usually a common pet in many homes. This zoonotic phenomenon represents an important health problem for any community.
Anatomía de Commelinaceae presentes en un cultivo de papas (Solanum tuberosuml.) en Mérida, Venezuela
LUQUE ARIAS,Rebeca; ESTRADA SáNCHEZ,Javier;
Acta Botánica Venezuelica , 2005,
Abstract: commelinaceae is, after poaceae and cyperaceae, the family of monocotiledons with the greatest number of weeds associated to cultures; among them, some species of commelina and tinantia are host for acarus, rust and virus, like the potato y potyvirus that affects solanum tuberosum. in the andes of mérida, commelina obliqua and tinantia erecta grow like weeds in cultivation of potato. to try to determine the existence of common and differential anatomical characters among them, as well as which anatomical characters favor its establishment in the cultivation, and the existence or not of characters that indicate the presence of possible pathogenic agents associated to them, the anatomy of its vegetative organs was carried out. both species have amphistomatic leaves, tall epidermical cells , thin cuticle; compact and well defined mesophyll; stem showing abundant adventitious roots; all of those being characters that permit the weed condition. in addition, the parenchyma cells of the leaves sheath seem to be filled with a plasmodium, suggesting infection by pathogens.
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