4 resultados para B. Microstructure-final

em Portal de Revistas Científicas Complutenses - Espanha


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In this paper we analyze the partial grades – of continuous assessment activities including the final exam – and the final grades – computed as a weighted average of partial grades – for nine subjects taught in the third year of Business Administration Degree. On one hand, results show that there is a significant positive correlation between the grades of continuous assessment activities (excluded the final exam) and final exam in seven subjects. On the other hand, overall we find that students’ grades in continuous assessment activities (excluded the final exam) help in the improvement of their final grades (i.e., students’ final grades exceed the grades that they would obtain by only taking into account their final exam grades). The results are consistent when the analysis is carried out over each subject area as well as over the grades of the students who registered for the nine subjects.

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Calcitic belemnite rostra are usually employed to perform paleoenvironmental studies based on geochemical data. However, several questions, such as their original porosity and microstructure, remain open, despite they are essential to make accurate interpretations based on geochemical analyses.This paper revisits and enlightens some of these questions. Petrographic data demonstrate that calcite crystals of the rostrum solidum of belemnites grow from spherulites that successively develop along the apical line, resulting in a “regular spherulithic prismatic” microstructure. Radially arranged calcite crystals emerge and diverge from the spherulites: towards the apex, crystals grow until a new spherulite is formed; towards the external walls of the rostrum, the crystals become progressively bigger and prismatic. Adjacent crystals slightly vary in their c-axis orientation, resulting in undulose extinction. Concentric growth layering develops at different scales and is superimposed and traversed by a radial pattern, which results in the micro-fibrous texture that is observed in the calcite crystals in the rostra.Petrographic data demonstrate that single calcite crystals in the rostra have a composite nature, which strongly suggests that the belemnite rostra were originally porous. Single crystals consistently comprise two distinct zones or sectors in optical continuity: 1) the inner zone is fluorescent, has relatively low optical relief under transmitted light (TL) microscopy, a dark-grey color under backscatter electron microscopy (BSEM), a commonly triangular shape, a “patchy” appearance and relatively high Mg and Na contents; 2) the outer sector is non-fluorescent, has relatively high optical relief under TL, a light-grey color under BSEM and low Mg and Na contents. The inner and fluorescent sectors are interpreted to have formed first as a product of biologically controlled mineralization during belemnite skeletal growth and the non-fluorescent outer sectors as overgrowths of the former, filling the intra- and inter-crystalline porosity. This question has important implications for making paleoenvironmental and/or paleoclimatic interpretations based on geochemical analyses of belemnite rostra.Finally, the petrographic features of composite calcite crystals in the rostra also suggest the non-classical crystallization of belemnite rostra, as previously suggested by other authors.

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El arteterapia permite una aproximación creativa biográfica particularmente valiosa en la etapa final de la vida. La persona enferma presenta múltiples necesidades – físicas, emocionales, sociales y espirituales – que solo una atención holística puede pretender abarcar, tal como lo contempla la filosofía de los cuidados paliativos. El arteterapeuta integrado en el equipo interdisciplinar contribuye a aliviar y acompañar el sufrimiento del paciente y su familia. Se presentan aquí las bases teóricas y la metodología de la intervención, así como el marco sanitario en el cual se inscribe.

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Este artículo analiza las estatuas-menhir noroccidentales que se distribuyen en el área comprendida entre los valles del río Duero y el río Miño, pero que descubrimientos recientes han extendido a regiones fuera de este área nuclear. Partiendo de tres aspectos claves para su interpretación (la cronología, su relación con el paisaje y su sentido iconográfico), se examinan las relaciones entre estas formas materiales y un paisaje socio-material de acción específico (las formas socio-materiales de interacción propias del Bronce final atlántico). Para ello, se tiene en cuenta diferentes conexiones materiales (presencia, encuentro, coexistencia, hibridación, etc.) que permiten contextualizar las estatuasmenhir dentro de un proceso histórico particular: la integración del noroeste de la península Ibrica en un contexto de relaciones mediterráneo-atlánticas, en la segunda mitad del II milenio a.C.