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Search Results: 1 - 10 of 10195 matches for " Alejandro; Tapia Conver "
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Iniciativa México: Propuesta para el control y vigilancia epidemiológica de la enfermedad de Chagas en México
Salazar Schettino,Paz María; Cravioto Q,Alejandro; Tapia Conver,Roberto;
Boletín chileno de parasitología , 2001, DOI: 10.4067/S0365-94022001000200008
Abstract: it is showed the programme for the knowledge, control and epidemiological surveillance of chagas disease in mexico.
Iniciativa México: Propuesta para el control y vigilancia epidemiológica de la enfermedad de Chagas en México Mexico iniciative: A proposal for the epidemiological control and surveillance of Chagas disease in Mexico
Paz María Salazar Schettino,Alejandro Cravioto Q,Roberto Tapia Conver
Boletín chileno de parasitología , 2001,
Abstract: It is showed the programme for the knowledge, control and epidemiological surveillance of Chagas disease in Mexico.
Sistema de apoyo a la toma de decisiones de establecimiento de plantaciones forestales
TAPIA TORO,PATRICIO ALEJANDRO; CEPEDA JUNEMANN,MANUEL;
Bosque (Valdivia) , 2005, DOI: 10.4067/S0717-92002005000300003
Abstract: forest companies are currently investing strong amount of money in establishment of plantations, that implies the carrying out of various kinds of silviculture-based works or procedures, these bring about additional costs to the plantation, and if being suitable for the site, they shall generate income increase by the time the forest is harvested. in this context, decisions to be made by the time a plantation is establish turn out to be critical with respect to the business income-yield capacity. therefore, and due to economic restraints, available resources have to be properly allotted in order to achieve improvement regarding forest business income-yield capacity, in the case of a group of forest stands that feature their own productivity, localization and gathering. the purpose of this current research work has been to improve the forest business income-yield capacity, by developing a support system regarding silviculture-based decision making in the establishment of forest plantations (proyman). by means of the use of this model a solution showing no establishment taking part, against a current silviculture decision, and one achieved by the decision making support system. outcomes showed that better general results were obtained by proyman, in terms of land expected value (lev). besides, it is important to stand out that key variables parameterization with respect to the establishment process turns out to be a necessary characteristic. likewise, it is quite important for a decision making support system, since the proper management of such decisions shall bring about the suitable and right solutions.
Sistema de apoyo a la toma de decisiones de establecimiento de plantaciones forestales Support system for decisions making for the establishment of forest plantations
PATRICIO ALEJANDRO TAPIA TORO,MANUEL CEPEDA JUNEMANN
Bosque (Valdivia) , 2005,
Abstract: Las empresas forestales invierten fuertes sumas de dinero en establecimiento de plantaciones, en la ejecución de una serie de intervenciones silvícolas que agregan costos a la plantación y, si éstas son adecuadas al sitio, generarán un aumento de los ingresos a obtener al momento de la cosecha del bosque. En este contexto, las decisiones que se tomen son determinantes en la rentabilidad del negocio forestal. Debido a esto y a la existencia de restricciones económicas, es necesario hacer una buena asignación de los recursos disponibles para lograr una mejora en la rentabilidad, para un conjunto de rodales con características propias de productividad, localización y agrupamiento. Con el objetivo de mejorar la rentabilidad del negocio forestal, se desarrolló un sistema de apoyo a la toma de decisiones de establecimiento de plantaciones (PROYMAN). Mediante el empleo de este modelo, se comparó una solución sin intervenciones de establecimiento versus una decisión silvicultural actual y una obtenida por el sistema. En general, PROYMAN obtuvo mejores soluciones en términos de Valor Potencial del Suelo (VPS). Es importante destacar que la parametrización de variables claves en el proceso de establecimiento es una característica necesaria y muy importante para un sistema de apoyo a la toma de decisiones, ya que de un adecuado manejo de éstas dependerá la bondad de las soluciones que genere. Forest companies are currently investing strong amount of money in establishment of plantations, that implies the carrying out of various kinds of silviculture-based works or procedures, these bring about additional costs to the plantation, and if being suitable for the site, they shall generate income increase by the time the forest is harvested. In this context, decisions to be made by the time a plantation is establish turn out to be critical with respect to the business income-yield capacity. Therefore, and due to economic restraints, available resources have to be properly allotted in order to achieve improvement regarding forest business income-yield capacity, in the case of a group of forest stands that feature their own productivity, localization and gathering. The purpose of this current research work has been to improve the forest business income-yield capacity, by developing a support system regarding silviculture-based decision making in the establishment of forest plantations (PROYMAN). By means of the use of this model a solution showing no establishment taking part, against a current silviculture decision, and one achieved by the decision making support system.
Segregated Distribution of Liriope tetraphylla, Aglaura hemistoma and Nausithoe punctata (Cnidaria) in the Southern Gulf of Mexico  [PDF]
César Flores-Coto, Alejandro Puente-Tapia, Laura Sanvicente A?orve, Mariana Fernández-Alamo
Open Journal of Ecology (OJE) , 2016, DOI: 10.4236/oje.2016.69055
Abstract: In order to study the segregated distribution of the three most abundant jellyfish species in the southern Gulf of Mexico, a total of 85 stations were sampled during an oceanographic cruise from 19 May to 18 June 2006. Trawling took place from surface to a maximum depth of 200 m, using a Bongo net with a 61 cm mouth diameter and 333 and 500 μm mesh sizes. Temperature and salinity were recorded. Samples were preserved in 4% formalin, neutralized with sodium borate, and changed to 70% ethylic alcohol after 24 hours for conservation. The jellyfish data were standardized to 100 m3 of filtered water. A total of 10,610 jellyfish were collected from the 333 μm mesh size net, of which eight species represented 88.49% of the total density: Aglaura hemistoma, Liriope tetraphylla, Nausithoe punctata, Clytia hemisphaerica, Persa incolorata, Obelia spp., Clytia folleata and Eutima gracilis. The former three species are the subject of this study. The results obtained indicate that the high density areas of these three species have a segregated distribution. Segregation values (White’s index) recorded between pairs of specie were very high: L. tetraphylla - A. hemistoma, 0.88; L. tetraphylla - N. punctata, 0.86 and A. hemistoma - N. punctata, 0.84. The spatial distribution of the high density areas of these species fits well with the three hydrodynamically different areas: A. hemistoma in Campeche Bank, L. tetraphylla on the Campeche and Tabasco shelves and N. punctata in Campeche Bay. This spatial distribution pattern corresponds to their main habitat and reproductive habits of the species, as well as the influence of the hydrodynamics that dominate each area.
7-(tert-Butyldiphenylsilyloxy)-2,2-dimethyl-1-benzofuran-3(2H)-one
Cristian O. Salas,Ricardo A. Tapia,Alejandro Macías
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536810054462
Abstract: The title compound, C26H28O3Si, is an allylic oxidation product of the tert-butyl(2,2-dimethyl-2,3-dihydrobenzofuran-7-yloxy)diphenylsilane with N-bromosuccinimide and 2,2′-azobis-isobutyronitrile. The nine-atom bicyclic system is almost planar, with an r.m.s deviation of 0.0123 (2) and a maximum deviation of 0.031 (2) for the O atom. In the crystal, the molecules pile up along the b axis but the strongest intermolecular contacts are the π–π stacking interactions between the benzene rings along the c axis [centroid–centroid distance = 3.655 (3) ].
Antioxidant responses of cortex neurons to iron loading
PABLA AGUIRRE,NATALIA MENA,VICTORIA TAPIA,ALEJANDRO ROJAS
Biological Research , 2006,
Abstract: Brain cells have a highly active oxidative metabolism, yet they contain only low to moderate superoxide dismutase and catalase activities. Thus, their antioxidant defenses rely mainly on cellular reduced glutathione levels. In this work, in cortical neurons we characterized viability and changes in reduced and oxidized glutathione levels in response to a protocol of iron accumulation. We found that massive death occurred after 2 days in culture with 10 mM Fe. Surviving cells developed an adaptative response that included increased synthesis of GSH and the maintenance of a glutathione-based reduction potential. These results highlight the fundamental role of glutathione homeostasis in the antioxidant response and provide novel insights into the adaptative mechanisms of neurons subjected to progressive iron loads.
Solución numérica de ecuaciones diferenciales lineales de segundo orden no homogéneas con coeficientes variables por el método de los elementos finitos
César R. Acosta,J. Alejandro Tapia,Maritza de Coss
Matemáticas : Ense?anza Universitaria , 2011,
Abstract: En este trabajo se introduce el concepto del funcional generalizado, al cual al aplicarle la ecuación de Euler se obtiene la ecuación diferencial a resolver. Se impone el método variacional al funcional, obteniéndose una función que es solución generalizada de la ecuación diferencial, la cual se expresa como integrales definidas por tramos, cada uno representa un segmento de recta definido entre dos puntos [yi, yi+1], contenidos en el rango total [a, b]. Al integrar para cada segmento de recta en todo el rango se tiene una ecuación lineal, al resolver el sistema de (N -1) ecuaciones con (N -1) incógnitas se tiene la solución numérica de la ecuación diferencial dada.
Variedades no convencionales como opción para elevar la productividad de maíces locales en valles altos de México
Alejandro Espinosa Calderón,Margarita Tadeo Robledo,Alfredo Tapia Naranjo
Agronomía Mesoamericana , 2000,
Abstract: Variedades no convencionales como opción para elevar la productividad de maíces locales en Valles Altos de México. En los Valles Altos de México (2200 a 2600 msnm), es escaso el uso de semilla mejorada (6%), además de variedades e híbridos que se promueven en el Programa Kilo por Kilo, serían convenientes otro tipo de variedades no convencionales, para ambientes de menor potencial productivo, no cubiertas actualmente, que permitan a los agricultores incrementar su propia semilla. Una posibilidad para mejorar los maíces criollos es combinarlos con algún híbrido que mejore características y eleve la productividad. En 1997 se cruzaron nueve maíces criollos, con un híbrido simple de porte intermedio y buena posición de mazorca, fueron evaluados en el ciclo primavera verano de 1998, en comparación con cada uno de sus progenitores y cinco testigos comerciales, los resultados se alan que los híbridos no convencionales superaron en rendimiento a las variedades criollas, ocho de los nueve fueron superiores numéricamente de 2% hasta 40%, al H-40, el mejor testigo comercial fue H-50 con 5462 kg./ha, el cual fue superado en 14.9% por la mejor cruza no convencional (6279 kg./ha). Los Híbridos no convencionales con respecto a las variedades nativas mejoraron en posición de mazorca y altura de planta, tolerancia al acame así como precocidad. Una buena alternativa para incrementar la productividad y mejorar algunas características agronómicas
Bioinformatic detection of E47, E2F1 and SREBP1 transcription factors as potential regulators of genes associated to acquisition of endometrial receptivity
Alejandro Tapia, Cristian Vilos, Juan Marín, Horacio B Croxatto, Luigi Devoto
Reproductive Biology and Endocrinology , 2011, DOI: 10.1186/1477-7827-9-14
Abstract: Gene expression datasets were intersected to determine a consensus endometrial receptivity transcript list (CERTL). For this cluster of genes we determined their functional annotations using available web-based databases. In addition, promoter sequences were analyzed to identify putative transcription factor binding sites using bioinformatics tools and determined over-represented features.We found 40 up- and 21 down-regulated transcripts in the CERTL. Those more consistently increased were C4BPA, SPP1, APOD, CD55, CFD, CLDN4, DKK1, ID4, IL15 and MAP3K5 whereas the more consistently decreased were OLFM1, CCNB1, CRABP2, EDN3, FGFR1, MSX1 and MSX2. Functional annotation of CERTL showed it was enriched with transcripts related to the immune response, complement activation and cell cycle regulation. Promoter sequence analysis of genes revealed that DNA binding sites for E47, E2F1 and SREBP1 transcription factors were the most consistently over-represented and in both up- and down-regulated genes during the window of implantation.Our research synthesis allowed organizing and mining high throughput data to explore endometrial receptivity and focus future research efforts on specific genes and pathways. The discovery of possible new transcription factors orchestrating the CERTL opens new alternatives for understanding gene expression regulation in uterine function.The human endometrium is a complex tissue whose cyclic regulation is mainly driven by the changing pattern of the ovarian steroidal hormones estradiol (E2) and progesterone (P4) [1]. The main function of the endometrium is to provide receptive substrate at the appropriate time for blastocyst implantation. Although it is non-adhesive to embryos throughout most of the menstrual cycle [2] the action of P4 on an E2-primed endometrium induces a certain gene expression profile that is favorable for blastocyst adhesion during a restricted period of time known as the 'window of implantation' [3,4]. In women, this maternal
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