Density functional/Monte Carlo study of ring-opening polymerization

Density functional calculations of the structure, potential energy surface and reactivity for organic systems closely related to bisphenol-A-polycarbonate (BPA-PC) provide the basis for a model describing the ring-opening polymerization of its cyclic oligomers by nucleophilic molecules. Monte Carlo simulations using this model show a strong tendency to polymerize that is increased by increasing density and temperature, and is greater in 3D than in 2D. Entropy in the distribution of inter-particle bonds is the driving force for chain formation. (C) 2002 Elsevier Science B.V. All rights reserved.

How teachers of Geography and History of Secondary Education assess?

The purpose of this article is to analyse the assessment procedures and instruments used by teachers of Geography and History of Compulsory Secondary School (ESO) in the Region of Murcia (Spain). The data have been extracted implementing a survey technique proceeded by a descriptive analysis. The results show that teachers generally have a traditional conception of assessment, reflected in the fact that they think that assessment should not change when teaching strategies are changed or when they innovate. On the other hand, although they consider that is necessary to employ a variety of instruments to assess well and to prevent school failure, they still use exams as the most objective and essential instrument in the assessment, while they don’t apply continuous assessment, only tests in a continuous way. The implementation of similar research in other areas or in other subjects shows the existence of contrasts in teacher assessment practices.

¿Barreras invisibles? Actitudes de los estudiantes universitarios ante sus compañeros con discapacidad

El presente trabajo analiza los conocimientos, opiniones y actitudes de los estudiantes universitarios sobre sus compañeros con discapacidad. La integración educativa y social de estos estudiantes es objeto de preocupación y estudio en todo el sistema educativo español, incluida la enseñanza superior en la que 21.942 universitarios con discapacidad se encontraban matriculados en el curso 2013-2014. El estudio se realiza en el marco de dos Proyectos de Innovación Educativa[1] de la Universidad de Málaga en los que se examinaron las actitudes del personal docente e investigador, el alumnado en general y el alumnado con discapacidad de esta institución. En este artículo se recogen las perspectivas de los estudiantes sin discapacidad, necesarias para medir el grado de aceptación dentro de las aulas universitarias. Se empleó una encuesta suministrada mediante correo electrónico a la totalidad de la población de estudiantes de la Universidad de Málaga (N= 32.464). El tamaño de la muestra fue de 620 estudiantes, por lo que trabajamos con un margen de error del 3,9% para la estimación de los porcentajes con un nivel de confianza del 95%. Los datos, analizados mediante análisis estadístico, visibilizan la importancia de un elevado grado de información y conocimiento así como de una experiencia directa con la discapacidad. Ambas circunstancias se traducen en actitudes más positivas y favorables. Tan solo el 20% de los alumnos manifestó haber recibido en alguna ocasión cualquier tipo de información sobre este asunto por parte de la Universidad; no obstante, la mayoría valora positivamente la presencia de alumnos con discapacidad en la Universidad, la posibilidad de contar ellos como compañeros de clase y el enriquecimiento que supone esta convivencia dentro del aula. Se discuten posibles acciones para mejorar las actitudes hacia los estudiantes con discapacidad. Además, se plantea incluir una perspectiva que promueva el empoderamiento de estos estudiantes. [1] PIE 10-135 y PIE 13-103.

Social networks and lifelong learning in older people

Various socio-demographic factors are causing our society to coexist every day with a group of elderly population that remains active and inserted into the daily dynamics. However, it is believed that there are certain barriers that make this group of people to not adequately address the technologies and even social networks. The creation of the University Programs for the Elderly (PUM), however, is leading to a new stage, since older people who participate come into contact with all kinds of content and rigor, updating own university education, thus changing the way to tackle the most innovative and different situations. In this study, we analyze what is the knowledge and use of older people, PUM, attending the University of Jaen have of the social networks and the assessment made of the need for these programs. To achieve this, we used a methodology in which qualitative and quantitative processes were articulated, through the analysis of data obtained from interviews and a focus groups with program Aquad 7. The data collected show that there is still some ignorance about social networks by older people, but everyone values their usefulness and necessity. Participants believe that they will be least affected of the risks of these technologies and demand a greater training in these contained within the PUM.

Polarisation independent bandpass FSS

The spectral transmittance of a frequency selective surface (FSS), which consists of two free-standing arrays of short-circuited nested annular slots, is presented. The FSS was designed to provide a minimum of 20 dB isolation between the frequency bands 316.5-325.5 and 349.5-358.5 GHz when the filter operates in the TE and TM planes at 45 degrees incidence. Experimental results, which are in close agreement with the computed transmission coefficients, show that the maximum insertion loss is 0.9 dB, and the minimum cross-polar discrimination is at least 21 dB in the passbands. The FSS yields virtually identical spectral responses in the two polarisation planes over the frequency range 315-359 GHz.

Effects of the acanthocephalan parasite Echinorhynchus truttae on the feeding ecology of Gammarus pulex (Crustacea : Amphipoda)

The amphipod Gammarus pulex is an intermediate host to the acanthocephalan fish parasite Echinorhynchus truttae. Gammarus pulex has a wide trophic repertoire, feeding as a herbivore, detritivore and predator. In this study an examination was made of the effects of E. truttae parasitism on components of the G. pulex diet: stream-conditioned leaves, dead chironomids and live juvenile isopods Asellus aquaticus. Over 21 days, parasitism had no effect on daily feeding rates or wet weights of G. pulex fed on leaves or chironomids. Parasitism had a significant effect on the number of A. aquaticus killed by G. pulex, with parasitized individuals killing significantly fewer than their unparasitized counterparts. In addition, unparasitized amphipods killed all size classes of A. aquaticus indiscriminately, whereas parasitized animals tended to kill the smaller size classes. The impacts of the parasitism of G. pulex throughout the wider freshwater community are discussed.

RAN GTPase is an effector of the invasive/metastatic phenotype induced by osteopontin.

Osteopontin (OPN) is a phosphorylated glycoprotein that binds to alpha v-containing integrins and is important in malignant transformation and cancer. Previously, we have utilized suppressive subtractive hybridization between mRNAs isolated from the Rama 37 (R37) rat mammary cell line and a subclone rendered invasive and metastatic by stable transfection with an expression vector for OPN to identify RAN GTPase (RAN) as the most overexpressed gene, in addition to that of OPN. Here we show that transfection of noninvasive R37 cells with an expression vector for RAN resulted in increased anchorage-independent growth, cell attachment and invasion through Matrigel in vitro, and metastasis in syngeneic rats. This induction of a malignant phenotype was induced independently of the expression of OPN, and was reversed by specifically reducing the expression of RAN using small-interfering RNAs. By using a combination of mutant protein and inhibitors, it was found that RAN signal transduction occurred through the c-Met receptor and PI3 kinase. This study therefore identifies RAN as a novel effector of OPN-mediated malignant transformation and some of its downstream signaling events in a mammary epithelial model of cancer invasion/metastasis.