Estrategias de comunicación utilizadas por aprendices de español como L2 y los efectos del tipo de tarea

Indexación: Scopus; Scielo.This study examines the possible effects of the task type on Spanish L2 learners’ strategic communication in face-to-face interactions with other learners and native speakers (NSs) of Spanish. Data was elicited from 36 interactions between Spanish L2 learners and native speakers of Spanish when carrying out two tasks, a jigsaw and a free-conversation activity. The data collection involved video and audio recording, observation of participants’ interactions and stimulated recall methodology. The spoken data was analysed based on Dӧrnyei and Kӧrmos’ taxonomy (1998) and the interactional CSs from Dӧrnyei and Scott's (1997). Quantitative and qualitative analyses were conducted to determine a possible association between CS use and the task factor as well as to identify the task effects. Findings show that there is an association between the task type and the learners’ use of CSs particularly influenced by the jigsaw. It seems that the task focus influences the use of certain CSs in order to fulfil the demands of each task. It was observed that the linguistic demands of the jigsaw and the cognitive demands of the free-conversation affected more the learners’ use of specific CSs.El objetivo de este estudio fue analizar los efectos del tipo de tarea en las estrategias de comunicación (EsC) que utilizan aprendices de español como L2 al interactuar cara a cara con otros aprendices y hablantes nativos del español. Se recolectó un corpus oral de 36 interacciones entre estos participantes al llevar a cabo dos tareas, una actividad jigsaw y una conversación. La recogida de datos se realizó mediante grabación de video y audio, observación y entrevistas retrospectivas. El análisis de la información se realizó en base a las taxonomías de Dӧrnyei y Kӧrmos (1998) y Dӧrnyei y Scott (1997). Los datos fueron analizados cuantitativa y cualitativamente para determinar una posible asociación entre el uso de EsC y la tarea realizada e identificar los efectos de la tarea. Los resultados indican una asociación entre el tipo de tarea y el uso de EsC, asociación que está particularmente influenciada por la actividad jigsaw. Se observó que el foco de las tareas afecta el uso de ciertas EsC utilizadas para cumplir con las demandas de cada actividad. Las demandas lingüísticas del jigsaw y las cognitivas de la conversación parecen afectar más el uso de ciertas EsC.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0718-09342018000100107&lng=en&nrm=iso&tlng=e

Examination of the Relationship Between Caesarean Section Births and Attention Deficit Hyperactivity Disorder

Attention Deficit/Hyperactivity Disorder, a neurological disorder characterized by inattentive and hyperactive behaviors, has become increasingly more prevalent (CDC, 2010). Recent research has found associations between this disorder and Caesarean section births (Amiri et al., 2012; Juarez et al., 2008). The current study examined the relationship between C-section birth and self-reported symptoms of ADHD by college students on the Internal Restlessness Scale (Weyandt et al., 2003). Results of the study indicate a significant difference in mean ratings of ADHD symptoms between C-section and vaginally born participants (t = 3.683, p \u3c .000). The current study supports previous findings of a relationship between C-sections and ADHD

Methanol dehydration over ZrO2 supported-activated carbons

Resumen comunicación congreso internacionalDME is playing an important role due to its potential use as an alternative fuel in diesel engines. The use of this fuel produces lower NOx emissions, and less engine noise compared to traditional diesel fuels. Moreover, this compound is used as building block for many value-added chemicals such as lower olefins. DME is usually produced via catalytic dehydration of methanol over a solid acid. The use of activated carbons in catalytic processes, acting directly as catalyst and as catalyst support, is focussing much attention. They can be obtained from different types of lignocellulosic waste, producing not only an environmental but an economical profit. In this sense, the preparation of activated carbons with phosphoric acid produces catalytic supports with certain surface acidity, which have shown high activity for alcohol dehydration. In this study, ZrO2 supported activated carbons were prepared from an industrial byproduct as lignin for the methanol dehydration to DME. The activated carbon was prepared by chemical activation with H3PO4, using Alcell® lignin as precursor. The impregnation ratio value (H3PO4/lignin) used was 3. The impregnated sample was activated under N2 flow at 500 ºC for 2h, washed and dried. The activated carbon was loaded with different amounts of ZrO(NO3)2, dried at 120ºC for 24h, and calcined in air at 250ºC for 2h, obtaining ZrO2 loadings of 5 and 10%, respectively. For the sake of comparison, pure ZrO2 was also used. Catalytic tests were performed at atmospheric pressure in a fixed bed reactor, at different space times and partial pressures. The activated carbon (ACP) prepared shows a well-developed porous structure, with an apparent surface area higher than 2000 m2/g, and a high contribution of mesoporosity. After metal loading, a maximum decrease of 20% in all structural parameters of the ACP was observed.The results show that ZrO2 loading produces an enhancing in the catalytic activity of the carbon materials compared to the parent activated carbon (0.1 g·s/μmol, PCH3OH= 0.02 atm in helium and 350 ºC). In this sense, a methanol conversion of 25% was observed with the addition of 10% w/w ZrO2 (ACP-10Zr), at steady state conditions (Figure 1). ACP shows negligible conversion, at the same conditions and for pure ZrO2 the methanol conversion was of 10%. Very high selectivity to DME (~100%) was found at temperatures lower than 350 ºC. The methanol conversion increases with temperature, reaching a value of 67% at 475ºC, but a slight decrease in DME selectivity is observed, resulting in a higher production of light hydrocarbons, mainly CH4. The results suggest that the addition of only a 10% of ZrO2 over an activated carbon prepared by chemical activation with H3PO4 enhances significantly the performance of the catalyst, compared to pure ZrO2.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Robustness of the European power grids under intentional attack

The power grid defines one of the most important technological networks of our times and sustains our complex society. It has evolved for more than a century into an extremely huge and seemingly robust and well understood system. But it becomes extremely fragile as well, when unexpected, usually minimal, failures turn into unknown dynamical behaviours leading, for example, to sudden and massive blackouts. Here we explore the fragility of the European power grid under the effect of selective node removal. A mean field analysis of fragility against attacks is presented together with the observed patterns. Deviations from the theoretical conditions for network percolation (and fragmentation) under attacks are analysed and correlated with non topological reliability measures.Comment: 7 pages, 4 figure

Compuesto etileno acetato de vinilo (EVA) reforzado con neumáticos fuera de uso (GTR) propiedades dieléctricas, mecánicas y térmicas

La masiva producción de neumáticos, así como su posterioralmacenamiento después de su utilización constituye un grave problema medioambiental al que se pretende dar salida con diversas soluciones. Una de ellas pasa por mezclar estos neumáticos reutilizados (Ground Tire Rubber GTR) con diversos polímeros termoplásticos, siendo esta opción la analizada en el presente trabajo, el cual tiene como objetivo obtener materiales aislantes adecuados para la industria eléctrica a partir de la mezcla del Etil-vínil Acetato (EVA) con neumáticos fuera de uso. Como exigencia principal se ha partido de unos costes mínimos de reciclado, es decir, mediante el uso del GTR sin desvulcanizary sin ningún pretratamiento previo con ácidos, pero en cambio actuando sobre la concentración y tamaños de las partículas del GTR, la cual se ha conseguido de una forma sencilla y económica como es el tamizado. Con este fin se han realizado análisis dieléctricos, mecánicos y térmicos de un gran número de compuestos obtenidos a partir de los tres tamaños de partículas del GTR (p<200μm, 200<p<500μm y p>500μm), y las siete concentraciones con las que se han formado los compuestos (0%, 5%, 10%, 20%, 40%, 50% y 70% en GTR). Todos estos datos han permitido una caracterización precisa de las propiedades de los nuevos compuestos y, de acuerdo con estos resultados y las Normativas vigentes, se han determinadoposibles aplicaciones eléctricas de los compuestos.