4 resultados para Edafología y Química Agrícola

em Portal de Revistas Científicas Complutenses - Espanha


Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the last years, “Inquiry-Based Science Education” methodologies (IBSE) are being recommended by European institutions in order to improve the competence levels and the attitudes towards science of primary and secondary school students. Therefore, the aim of this study is to test the effectiveness of an IBSE methodology, the Methodology of Problem Solving as an Investigation (MPSI), for the teaching-learning process of planning of experiments in the fourth level of Spanish Secondary Education. By means of the students’ solutions for a series of open problems, the progress in the learning of the competences related to the planning of experiments has been analyzed, along with the influence of the methodology on the development of these competencies. The results show a students’ command from higher to lower levels on: emission of hypothesis, design of the experiment, qualitative analysis, identification of variables and reformulation of the open problem. Furthermore, the Methodology has contributed to an improvement of the scientific competence in the area of planning experiments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mineral and chemical composition of alluvial Upper-Pleistocene deposits from the Alto Guadalquivir Basin (SE Spain) were studied as a tool to identify sedimentary and geomorphological processes controlling its formation. Sediments located upstream, in the north-eastern sector of the basin, are rich in dolomite, illite, MgO and KB2BO. Downstream, sediments at the sequence base are enriched in calcite, smectite and CaO, whereas the upper sediments have similar features to those from upstream. Elevated rare-earth elements (REE) values can be related to low carbonate content in the sediments and the increase of silicate material produced and concentrated during soil formation processes in the neighbouring source areas. Two mineralogical and geochemical signatures related to different sediment source areas were identified. Basal levels were deposited during a predominantly erosive initial stage, and are mainly composed of calcite and smectite materials enriched in REE coming from Neogene marls and limestones. Then the deposition of the upper levels of the alluvial sequences, made of dolomite and illitic materials depleted in REE coming from the surrounding Sierra de Cazorla area took place during a less erosive later stage of the fluvial system. Such modification was responsible of the change in the mineralogical and geochemical composition of the alluvial sediments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Con este trabajo nos proponemos estudiar las políticas agrarias del franquismo y particularmente la creación y actuación del Servicio de Extensión Agraria (1955) en el contexto de la difusión de la Teoría de la Modernización. Comenzaremos con una contextualización de las relaciones culturales entre España y los EE.UU. y su potencial proyección sobre el ámbito rural. A continuación, prestaremos atención a la impronta del modelo extensionista norteamericano en la organización y metodología del Servicio de Extensión Agraria. Sin perder de vista la importancia de la escala estatal para la implementación y adaptación de las distintas políticas agrarias, atenderemos al contexto político e ideológico internacional como elemento que permite ampliar la comprensión y estudio de dichas políticas. En ese sentido, propondremos finalmente una primera aproximación comparativa al estudio del SEA en relación con diferentes experiencias de extensionismo agrario en Latinoamérica.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Se estudia la distribución peninsular y la composición en derivados del b-orcinol de Melanelia acetabulum (Neck.) Essl. Las muestras mediterráneas analizadas presentan constantemente ácidos connorestícticos y norestíctico, careciendo de ácido salacínico y atranorina. Las muestras de la única localidad eurosiberiana estudiada presentan las mismas depsidonas, pero además contienen pequeñas cantidades de atranorina. Se discute, en base a estos resultados, la relación entre Melanelia acetabulum y M. koflerae (Clauzade & Poelt) Essl.