Simposio : los libros de texto : análisis y propuestas de futuro

En este simposio se reúnen comunicaciones que tienen como foco principal el análisis de los textos que se utilizan en las clases de ciencias con la finalidad de identificar las características que los hacen útiles para la enseñanza de las ciencias y, a partir de ello, proponer nuevos enfoques de futuro

Triple correlation for detection of damage-related nonlinearities in composite structures

Nonlinear effects in vibration responses are investigated for the undamaged composite plate and the composite plate with a delamination. The analysis is focused on higher harmonic generation in vibration responses for various excitation amplitude levels. This effect is investigated using the triple correlation technique. The dynamics of composite plate was modelled using two-dimensional finite elements and the classical lamination theory. The doubled-node approach was used to model delamination area. Mode shapes and natural frequencies were estimated based on numerical models. Next, the delamination divergence analysis was used to obtain relative displacements for delaminated plies. Experimental modal analysis test was carried out to verify the numerical models. The two strongest vibration modes as well as two vibration modes with the smallest and largest motion level of delaminated plies were selected for nonlinear vibration test. The Fisher criterion was employed to verify the effectiveness and confidence level of the proposed technique. The results show that the method can be used not only to reveal nonlinearities, but also to reliably detect impact damage in composites. These results are confirmed using the statistical analysis

Energy absorption capability of nanomodified glass/epoxy laminates

Abstract The impact response of standard and clay-modified vacuum-infused glass/epoxy laminates was investigated. The activity was oriented to evaluate the enhancements in the energy absorption capability of the laminates due to the nanomodification. Nanomodification was achieved by using Cloisite 30B nanoclays by Southern Clay. Low velocity impact tests were carried out on flat samples of about 4 mm thicknessby a drop-weight tower. The results clearly indicate that the nanomodified laminates have a greater capability to absorb the impact energy (with up to 30% increases in dissipated energy) with respect to the standard laminates, also in combination with a decrease of the peak impact force (from 10 to 15%). In some ways, this behaviour can be partly justified by the larger damage exhibited by nanomodified laminates, with projected damage areas more than double the damage areas of standard panels, for the same impact energy

Chalet en Somosaguas, Madrid – España

This project has a very specific internal distribution, due to the requirements imposed by the owners, Cie. de Saint Gobain. The purpose of the bungalow is to house the senior members of the firm during their visits to Madrid. Both the external and internal design of volumes and spaces and the Castillan type decoration have been very carefully adapted to its intended purpose.Esta vivienda responde a una distribución especial, consecuencia de las necesidades impuestas por la entidad propietaria —Cié. de Saint Gobain—, ya que tenía que cumplir una función determinada y muy concreta: albergar a los altos cargos de la Empresa en sus visitas a Madrid. Tanto la organización de espacios abiertos y cerrados como la decoración interior y exterior (estilo castellano), se han cuidado en extremo en una interpretación acertada del programa previsto

Potentially probiotic and bioprotective lactic acid bacteria starter cultures antagonise the Listeria monocytogenes adhesion to HT29 colonocyte-like cells

The capability of five lactic acid bacteria (LAB) to counteract the adhesion of Listeria monocytogenes to the epithelial intestinal cell line HT29 was studied. The highest adhesion ability to HT29 was achieved by the intestinal strain Lactobacillus rhamnosus CTC1679, followed by the meat-derived strains Lactobacillus sakei CTC494 and Enterococcus faecium CTC8005. Surprisingly, the meat strains showed significantly better adhesion to HT29 than two faecal isolates of Lactobacillus casei and even significantly higher than the reference strain L. rhamnosus GG. Additionally, the anti-listerial, bacteriocin-producer starter culture L. sakei CTC494 was able to significantly reduce the adhesion of L. monocytogenes to HT29 in experiments of exclusion, competition and inhibition. The performance was better than the faecal isolate L. rhamnosus CTC1679. Our results reinforce the fact that the ability of LAB to interact with a host epithelium model, as well as to antagonise with foodborne pathogens, is a strain-specific characteristic. Additionally, it is underlined that this trait is not dependent on the origin of the bacterium, since some food LAB behave better than intestinal ones. Therefore, the search for novel strains in food niches is a suitable approach to find those with potential health benefits. These strains are likely pre-adapted to the food environment, which would make their inclusion in the formulation of probiotic foods more feasible. © 2014 Wageningen Academic Publishers.Peer Reviewe

Distintas narrativas para un mismo contenido : la tabla periódica en los libros de texto

Se analizan las ‘narrativas’ implícitas en una muestra amplia de libros de texto para establecer una tipologia que tiene implicaciones en la selección de los contenidos de los temas que se tratan en el libro. Se ha centrado el estudio en la Tabla periódica de los elementos, siguiendo las investigaciones de Linares (2004) y Izquierdo y Adúriz (2007). Los resultados del análisis que se ha realizado en una muestra amplia de libros de texto a partir de los años cincuenta muestran que la manera de presentar a la Tabla Periódica en el libro intenta ser coherente con el enfoque global de la química en él. Ahora bien, se detectan incoherencias que nos llevan a proponer un foro de discusión sobre el diseño de los contenidos de química a la luz de las propuestas didácticas actuales y sobre la función actual de los libros de texto en la enseñanza de la Química

Enhanced recovery after surgery pathways in thoracic surgery, do they end at discharge?

Fast track pulmonary resection protocols have shown to be feasible and to improve hospital related costs, shortening length of stay and maintaining quality of care (1-4). Despite the increasing number of scientific literature addressing the benefits of specific lobectomy pathways (4,5) and the recent publication of Enhanced Recovery after Surgery (ERAS®) guidelines in thoracic surgery (4-6) the truth is that the description of most of these interventions ends at patients’ discharge, with no clear indications for follow up or measures to prevent unintended hospital readmissions (2,3