7 resultados para SPERM COMPETITION

em Archivo Digital para la Docencia y la Investigación - Repositorio Institucional de la Universidad del País Vasco


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We model the Spanish wholesale market as a multiplant linear supply function competition model. According to the theory, the larger generators should have supply curves for each plant which are to the left of the supply curves of plants owned by smaller generators. We test this prediction for fuel plants using data from the Spanish Market Operator (OMEL) from May 2001 to December 2003. Our results indicate that the prediction of the model holds.

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The role of Na+ fluxes through voltage-gated sodium channels in the regulation of sperm cell function remains poorly understood. Previously, we reported that several genes encoding voltage-gated Na+ channels were expressed in human testis and mature spermatozoa. In this study, we analyzed the presence and function of the TTX-resistant VGSC a subunit Na(v)1.8 in human capacitated sperm cells. Using an RT-PCR assay, we found that the mRNA of the gene SCN10A, that encode Na-v1.8, was abundantly and specifically expressed in human testis and ejaculated spermatozoa. The Na-v1.8 protein was detected in capacitated sperm cells using three different specific antibodies against this channel. Positive immunoreactivity was mainly located in the neck and the principal piece of the flagellum. The presence of Na-v1.8 in sperm cells was confirmed by Western blot. Functional studies demonstrated that the increases in progressive motility produced by veratridine, a voltage-gated sodium channel activator, were reduced in sperm cells preincubated with TTX (10 mu M), the Na-v1.8 antagonist A-803467, or a specific Na-v1.8 antibody. Veratridine elicited similar percentage increases in progressive motility in sperm cells maintained in Ca2+-containing or Ca2+-free solution and did not induce hyperactivation or the acrosome reaction. Veratridine caused a rise in sperm intracellular Na+, [Na+](i), and the sustained phase of the response was inhibited in the presence of A-803467. These results verify that the Na+ channel Na-v1.8 is present in human sperm cells and demonstrate that this channel participates in the regulation of sperm function.

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Para quien es de utilidad: •Alumnos de Tª Microeconómica IV, curso 3º LE. •Alumnos de las asignaturas de Tª de Juegos y Organización Industrial del Máster en Economía: Instrumentos del Análisis Económico. Estas notas sobre competencia imperfecta están dedicadas al estudio de estructuras de mercado caracterizadas por la existencia de poder de mercado. Se estudia en primer lugar el monopolio, dedicando una atención especial a los diferentes tipos de discriminación de precios. A continuación se presenta la Tª de juegos no cooperativos y se muestra su utilidad para analizar diferentes fenómenos económicos caracterizados por la interdependencia estratégica. Finalmente, se estudian diferentes modelos de competencia oligopolística y la estabilidad de los acuerdos colusivos.

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Documento de trabajo

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Recent experimental work in the field of synthetic protocell biology has shown that prebiotic vesicles are able to 'steal' lipids from each other. This phenomenon is driven purely by asymmetries in the physical state or composition of the vesicle membranes, and, when lipid resource is limited, translates directly into competition amongst the vesicles. Such a scenario is interesting from an origins of life perspective because a rudimentary form of cell-level selection emerges. To sharpen intuition about possible mechanisms underlying this behaviour, experimental work must be complemented with theoretical modelling. The aim of this paper is to provide a coarse-grain mathematical model of protocell lipid competition. Our model is capable of reproducing, often quantitatively, results from core experimental papers that reported distinct types vesicle competition. Additionally, we make some predictions untested in the lab, and develop a general numerical method for quickly solving the equilibrium point of a model vesicle population.

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World Conference on Psychology and Sociology 2012