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Search Results: 1 - 10 of 477829 matches for " García-González "
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The relative nature of fertilization success: Implications for the study of post-copulatory sexual selection
Francisco García-González
BMC Evolutionary Biology , 2008, DOI: 10.1186/1471-2148-8-140
Abstract: Fertilization success values render biased sperm competitive ability values. Furthermore, asymmetries among males in the errors committed when estimating sperm competitive abilities are likely to exist as long as males exhibit variation in sperm competitiveness. Critically, random effects arising from the relative nature of fertilization success lead to an underestimation of underlying additive genetic variance in sperm competitive ability.The results show that, regardless of the existence of genotypic interactions affecting the output of sperm competition, fertilization success is not a perfect predictor of sperm competitive ability because of the stochasticity of the background used to obtain fertilization success measures. Random effects need to be considered in the debate over the maintenance of genetic variation in sperm competitiveness, and when testing good-genes and compatible-genes processes as explanations of polyandrous behaviour using repeatability/heritability data in sperm competitive ability. These findings support the notion that the genetic incompatibility hypothesis needs to be treated as an alternative hypothesis, rather than a null hypothesis, in studies that fail to detect intrinsic sire effects on the sperm competitiveness phenotype.A wealth of research inspired by Parker's [1] seminal study on sperm competition has provided overwhelming evidence that mating success is not always equivalent to reproductive success [1-4]. Sperm competition, a direct consequence of polyandry (females mating with different partners within a single reproductive episode), can contribute to the maintenance of promiscuity if females accrue benefits from encouraging the overlap of ejaculates at the site of fertilization. The sexy-sperm hypothesis, a post-copulatory analogue of the sexy-sons model for the evolution of female preferences and male attractiveness [5-7], suggests that polyandrous females could enhance their fitness if fertilization success is genetically co
Acción vaso-periférica del extracto acuoso de las hojas de Clusia coclensis (Clusiaceae)
García-González,Mildred;
Revista de Biología Tropical , 1998,
Abstract: aqueous leaf extract of clusia coclensis was applied at a dose of 40 mg/kg intravenously to isolated posterior extremities of six normotensive sprague-dawley rats and six spontaneously hipertensive rats anaesthetized with sodium nembutal. the perfusion was done in the abdominal artery using as carrier krebs bicarbonate ringer at 37 °c and keeping constant perfusion pressures of 100 mmhg in normotensive rats and 150 mmhg in hipertensive ratas. the venous return was measured in the inferior vena cava. the extract induced a significant reduction of the venous return begining 2 min after application, in both rat types. this may reflect a peripheral vasoconstriction that, in whole organism,would have an hipertensive effect. therefore, the mechanism of the alledgedly systemic hipotensive effect of the aqueous extract of clusia coclensis leafs resides probably at a central level, probably acting by a reduction of the contractibility of the myocardium.
Elementos para una filogeografía de la cabra montés ibérica (Capra pyrenaica schinz, 1838)
García-González, Ricardo
Pirineos : Revista de Ecología de Monta?a , 2011,
Abstract: In order to provide some issues for a future study of Capra pyrenaica phylogeography I review classic and recent works considering data of genetic studies known to date, as well as recent findings related to paleontology and biometrics. C. pyrenaica has experienced several population bottlenecks throughout its history that have led to a loss of genetic diversity. In addition, numerous recent translocations and population reinforcements can complicate the clarification of intraspecific genetic differentiation. I review current theories about the evolution of the species. One of them establishes a recent evolution (past 18,000 years) from ancestors related to C. caucasica. I analyze in some detail the morphological characters (mainly teeth and horns) on which this theory is based, showing their high variability. Present genetic studies show a clear relationship between C. pyrenaica and Alpine ibex (C. i. ibex). They also show a north-south genetic differentiation between Iberian goats, occupying the Pyrenean goats (C. p. pyrenaica) an intermediate position between Alpine ibex and southern Iberian goats. Recent paleontological findings evidence an ancient presence (Lower Pleistocene) of Capra in the Iberian Peninsula. I propose the hypothesis that the descendants of these ancient goats, may have come into contact with C. ibex in the Pyrenees and southern France, one or more times during the Upper Pleistocene. Intermediate characteristics, both genetic and biometric, of the extinct Pyrenean goats, would agree with this hypothesis. New paleontological records and more genetic studies (including fossil and recent materials) are necessary, to elucidate both the phylogeny of C. pyrenaica and its intraspecific diversification. En este trabajo se realiza una revisión sintética de los trabajos clásicos y recientes que conciernen a la filogeografía de Capra pyrenaica, aportando datos de los estudios genéticos conocidos hasta la fecha, así como de nuevos hallazgos relativos a su paleontología y biometría. C. pyrenaica ha experimentado varios cuellos de botella poblacionales a lo largo de su historia que han producido pérdida de diversidad genética. Al mismo tiempo, numerosas traslocaciones y reforzamientos poblacionales pueden complicar la clarificación de su diferenciación genética a nivel intraespecífico. Se revisan algunas teorías actuales sobre la evolución de la especie, que contemplan su evolución reciente (últimos 18.000 a os) a partir de ancestros afines a C. caucasica. Se examinan con cierto detalle los caracteres morfológicos en los que se basa dicha teoría
Acción vaso-periférica del extracto acuoso de las hojas de Clusia coclensis (Clusiaceae)
Mildred García-González
Revista de Biología Tropical , 1998,
Abstract: Se inyectó extracto acuoso de hojas de Clusia coclensis en dosis de 40 mg/kg por vía endovenosa en el tren posterior aislado de 6 ratas normotensas (SDN) y 6 ratas hipertensas (SHR). El extracto provocó en ambas cepas de ratas una reducción significativa del retorno venoso. Se concluye que el extracto de Clusia provoca un efecto vasoconstrictor periférico, por lo que el efecto hipotensor y anti-hipertensivo encontrado anteriormente, podría ser atribuido a un efecto directo sobre el miocardio, mediante una disminución en la fuerza de la contracción cardíaca (efecto inotrópico negativo). Aqueous leaf extract of Clusia coclensis was applied at a dose of 40 mg/kg intravenously to isolated posterior extremities of six normotensive Sprague-Dawley rats and six Spontaneously Hipertensive rats anaesthetized with sodium nembutal. The perfusion was done in the abdominal artery using as carrier Krebs bicarbonate ringer at 37 °C and keeping constant perfusion pressures of 100 mmHg in normotensive rats and 150 mmHg in hipertensive ratas. The venous return was measured in the inferior vena cava. The extract induced a significant reduction of the venous return begining 2 min after application, in both rat types. This may reflect a peripheral vasoconstriction that, in whole organism,would have an hipertensive effect. Therefore, the mechanism of the alledgedly systemic hipotensive effect of the aqueous extract of Clusia coclensis leafs resides probably at a central level, probably acting by a reduction of the contractibility of the myocardium.
Las mujeres, en el ámbito de la producción publicitaria. Estudio del sector publicitario gallego desde una perspectiva de género
Aurora García-González
Revista Latina de Comunicación Social , 2011,
Abstract: En los últimos a os, la publicidad ha recibido numerosas críticas ante el abuso que sus mensajes realizan de determinadas representaciones de género. Unos mensajes que son fruto de un cuidado proceso de elaboración, en el que se reflejan los valores y actitudes de los profesionales implicados.La hipótesis de partida de esta investigación ha sido la de considerar que la persistencia de estereotipos sexistas en la publicidad está relacionada con la ausencia de mujeres en aquellos departamentos vinculados al arte final.En este sentido, el objeto de este trabajo ha sido conocer la situación de las mujeres dentro del sector publicitario gallego, con especial atención a su participación en la creación de los mensajes. Un estudio que ha sido abordado desde la perspectiva del proceso de producción publicitaria y que pretende establecer comparación con la situación de las trabajadoras en el mercado publicitario estatal.
Women in advertising production. Study of the Galician advertising sector from a gender perspective
Aurora García-González
Revista Latina de Comunicación Social , 2011,
Abstract: In recent years, the advertising sector has been strongly criticised due to its sexist representation of gender. The messages in advertisements are the result of a careful manufacturing process, which reflects the values and attitudes of the professionals involved in their creation. The main research hypothesis of this article is that the persistence of sexist stereotypes in advertising is related to the absence of women in the creative departments of advertising agencies. In this sense, the objective of this work is to examine the situation of women within the Galician advertising sector, and particularly women’s participation in ads production. This study, which has been carried out from the production perspective, also compares the situation of women in the Galician advertising agencies with the general situation of women in the national advertising sector.
Activity rhythms and the influence of some environmental variables on summer ungulate behaviour in Ordesa-Monte Perdido National Park
Aldezabal, A.,Garin, I.,García-González, R.
Pirineos : Revista de Ecología de Monta?a , 1999,
Abstract: We have studied daily activity rhythms and time-budgets of four large herbivores (cattle, sheep, goats and chamois) which form a multi-species grazing system in a summer pastoral unit of the Central Pyrenees. Also, the influence of some environmental variables (altitude, slope and plant cover) on the main activities has been appraised. Grazing is the activity to which most time is dedicated in all the species: cattle 48%, sheep 53%, goats 55% and chamois 68%. Cattle is the species with the highest resting rate (41%) and sheep is the species spends most time walking (35%). Results suggest the existence of an inverse relationship between body size and grazing time. Cattle show two clear grazing peaks during the day at early morning and late evening. Contrary to this, sheep and chamois show a multimodal pattern, with some peaks for this activity throughout the day. Environmental factors clearly influence cattle and chamois activities. Sheep and goats show a less definite pattern in respect to environmental factors, probably because of their herded condition. [es] Se estudian los ritmos de actividad diarios y la distribución del tiempo entre diferentes actividades, de cuatro grandes herbívoros (vacas, ovejas, cabras y rebecos) que utilizan durante el verano la misma unidad pastoral (Puerto de Góriz, Parque Nacional de Ordesa) en el Pirineo Central. Asimismo, se determina la influencia de diversas variables ambientales (altitud, pendiente y cobertura vegetal) sobre la conducta de dichos rumiantes. El pastoreo es la actividad a la que más tiempo dedican todas las especies: vacas 48%, ovejas 53%, cabras 55% y rebecos 68%. El ganado vacuno es la especie que más tiempo dedica al descanso (41%) y el ovino el que más tiempo emplea en desplazarse (35%). Los resultados sugieren la existencia de una relación inversa entre tama o corporal y tiempo dedicado al pastoreo, ya apuntada por otros autores. Vacas y cabras presentan dos períodos máximos de pastoreo a primeras horas de la ma ana y al atardecer, mientras que ovejas y rebecos presentan varios máximos de pastoreo a lo largo del día. Vacas y rebecos muestran claras relaciones entre varios tipos de actividad y los factores ambientales, mientras que la relación es menos aparente para ovejas y cabras. [fr] Nous avons étudié les rythmes d'activité journaliers ainsi que la distribution temporelle des différents types de comportement de quatre ongulés {vaches, brebis, chèvres et isards); ils utilisent la même unité pastorale (estive de Goriz) dans les Pyrénées Centrales, au Parc National d'Ordesa. Aussi nous avons evalué
Amyloidogenic Properties of a D/N Mutated 12 Amino Acid Fragment of the C-Terminal Domain of the Cholesteryl-Ester Transfer Protein (CETP)
Victor García-González,Jaime Mas-Oliva
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12032019
Abstract: The cholesteryl-ester transfer protein (CETP) facilitates the transfer of cholesterol esters and triglycerides between lipoproteins in plasma where the critical site for its function is situated in the C-terminal domain. Our group has previously shown that this domain presents conformational changes in a non-lipid environment when the mutation D 470N is introduced. Using a series of peptides derived from this C-terminal domain, the present study shows that these changes favor the induction of a secondary β-structure as characterized by spectroscopic analysis and fluorescence techniques. From this type of secondary structure, the formation of peptide aggregates and fibrillar structures with amyloid characteristics induced cytotoxicity in microglial cells in culture. These supramolecular structures promote cell cytotoxicity through the formation of reactive oxygen species (ROS) and change the balance of a series of proteins that control the process of endocytosis, similar to that observed when β-amyloid fibrils are employed. Therefore, a fine balance between the highly dynamic secondary structure of the C-terminal domain of CETP, the net charge, and the physicochemical characteristics of the surrounding microenvironment define the type of secondary structure acquired. Changes in this balance might favor misfolding in this region, which would alter the lipid transfer capacity conducted by CETP, favoring its propensity to substitute its physiological function.
Virología, epidemiología y mecanismos de transmisión del VHB
Moreno,D.; Alegre,F.; García-González,N.;
Anales del Sistema Sanitario de Navarra , 2004, DOI: 10.4321/S1137-66272004000400002
Abstract: illness due to the hepatitis b virus is an enormous problem for international public health, affecting over 300 million persons throughout the world, although its prevalence varies considerably between different geographic areas. the universal vaccination of the newly born, promulgated by the world health organisation, has made it possible to partially control the spread of the virus in many countries, including spain. however, the vaccine does not generate protective antibodies in approximately 5% of the population. besides, infection by the hepatitis b virus can produce few symptoms and the virus is easily transmitted, making its epidemiological control difficult. on the other hand, the growing flow of bi-directional migration of persons between geographical areas with a moderate or high prevalence and spain also seems to be contributing to the persistence of the disease in our milieu. all of this makes it compulsory to deploy an ensemble of preventive measures based on an increasingly deep understanding of the biological cycle of the virus. in spain, as in other regions with a low prevalence, the hepatitis b virus infection is considered chiefly to be a disease of sexual transmission, or else contagion takes place between patients who are users of intravenous drugs. on the other hand, blood transmission is of scarce importance in our milieu. following exposure to the hepatitis b virus, prophylaxis with immunoglobins and also the administration of the vaccine is highly effective, and acquires special interest for all healthcare workers.
Sensors: From biosensors to the electronic nose
García-González, Diego L.,Aparicio, Ramón
Grasas y Aceites , 2002,
Abstract: The recent advances in sensor devices have allowed the developing of new applications in many technological fields. This review describes the current state-of-the-art of this sensor technology, placing special emphasis on the food applications. The design, technology and sensing mechanism of each type of sensor are analysed. A description of the main characteristics of the electronic nose and electronic tongue (taste sensors) is also given. Finally, the applications of some statistical procedures in sensor systems are described briefly. Los recientes avances en los sistemas de sensores han permitido el desarrollo de nuevas aplicaciones en muchos campos tecnológicos. Este artículo de revisión describe el estado actual de esta nueva tecnología, con especial énfasis en las aplicaciones alimentarias. El dise o, la tecnología y el mecanismo sensorial de cada tipo de sensor son analizados en el artículo. También se describen las principales características de la nariz y la lengua electrónica (sensores de sabor). Finalmente, se describe brevemente el uso de algunos procedimientos estadísticos en sistemas de sensores.
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