Simón Bolívar University

About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.

Brane-world stars from minimal geometric deformation, and black holes

Abstract: We build analytical models of spherically symmetric stars in the brane-world, in which the external space-time contains both an ADM mass and a tidal charge In order to determine the interior geometry, we apply the principle of minimal geometric deformation, which allows one to map General Relativistic solutions to solutions of the effective four-dimensional brane-world equations We further restrict our analysis to stars with a radius linearly related to the total General Relativistic mass, and obtain a general relation between the latter, the brane-world ADM mass and the tidal charge In these models, the value of the star’s radius can then be taken to zero smoothly, thus obtaining brane-world black hole metrics with a tidal charge solely determined by the mass of the source and the brane tension General conclusions regarding the minimum mass for semiclassical black holes will also be drawn

Validez y confiabilidad en la metodología cualitativa

Abstract: Este articulo trata de clarificar la frecuente confusion que tienen muchos investigadores al utilizar los criterios relacionados con la validez y la confiabilidad en una investigacion, ya sea de orientacion cuantitativa tradicional o cualitativa. Se hace enfasis en el enfoque epistemologico de cada una como base de todo, en sus caracteristicas propias y, principalmente, se resalta el proceso eminentemente critico que acompana a la metodologia cualitativa en todas sus fases: procesos de acopio de la informacion, de categorizacion, de estructuracion, de contrastacion y de teorizacion, y, de una manera especial, en los criterios de evaluacion de los resultados o estructuras teoricas como objetivo final de la investigacion. Palabras Clave: validez, confiabilidad, epistemologia, metodologia cualitativa Abstract This article tries to clarify the frequent confusion that many investigators have when using the approaches related to the validity and reliability in an investigation of the traditional quantitative orientation or the qualitative one. Emphasis is made on the epistemological focus of each one like base of everything, on its own characteristics and, mainly, on the eminently critical process that accompanies the qualitative methodology in all its phases: processes of information gathering, of categorization, of structuring, of “contrasting”, and of teorization, and, in a special way, in the approaches to the evaluation of results or theoretical structures as final objective of the investigation. Key words: validity, reliability, epistemology, cualitative metodology.

Chemical, biological and sensory evaluation of pasta products supplemented with α-galactoside- free lupin flours

Abstract: α-Galactoside-free lupin flour has been used to supplement durum wheat semolina flour in order to increase the nutritive value of pasta products. Supplemented pasta products had a shorter cooking time, higher cooking water absorption, cooking loss and protein loss in water than control pasta prepared with only semolina. Sensory evaluation of cooked pastas showed that products supplemented with 80 g kg−1 of α-galactoside-free Lupinus angustifolius var. Emir flour or with 100 g kg−1 of α-galactoside-free Lupinus angustifolius var. Troll flour showed the same acceptability by panellists as the semolina pasta. These levels of supplementation were selected for further studies. The cooked α-galactoside-free lupin/semolina pastas showed higher amounts of protein, dietary fibre, calcium, phosphorus, magnesium, zinc and antioxidant capacity than control pasta and a reasonable level of vitamin B1, vitamin B2 and vitamin E. Biological assessment of cooked pastas indicated that the true protein digestibility did not change after the fortification of semolina but protein efficiency ratio increased sharply in the pasta supplemented with α-galactoside-free lupin flours (2.07 and 1.92 for Emir and Troll lupin varieties, respectively) in comparison with the control pasta (1.11). It is concluded that the α-galactoside-free lupin flours are an adequate ingredient to improve the nutritional quality of pasta products without adding flatulent oligosaccharides. Copyright © 2006 Society of Chemical Industry