Lectura, experimentación y nuevas tecnologías en la enseñanza de los modelos atómicos

The scientific concepts related to the matter structure and the atomic models are difficult topics to be understood by students in Physics and Chemistry classes. This difficulty could be associated with the contents own abstraction and the way they are covered in school textbooks, which promote a fragmented and decontextualized learning that does not emphasize the circumstances and the questionings that led to the substitution of one model for another. Taking the previous issue into account, we designed and implemented a didactic unit that combines reading comprehension, experimentation and the use of simulations with students attending 3rd year in a preuniversity school in San Juan. In this article we present the most distinctive aspects of the proposal and the results of its implementation, which show significant achievements as regards the learning of the disciplinary content as well as motivation aspects related to the resources used and the tasks proposed.  Los contenidos científicos relacionados con la estructura de la materia y los modelos atómicos son temas difíciles de comprender por los estudiantes en los espacios curriculares de Física y Química. Esta dificultad puede asociarse a la abstracción propia de los contenidos y al abordaje que se realiza en los manuales escolares, los cuales promueven un aprendizaje fragmentado y descontextualizado que no enfatiza las circunstancias y los interrogantes que condujeron a la sustitución de un modelo por otro. Teniendo en cuenta lo expuesto, diseñamos e implementamos una propuesta didáctica que conjuga la lectura de textos, la experimentación y el uso de simulaciones con alumnos de 3° año de un instituto preuniversitario de San Juan. En este artículo presentamos los aspectos más representativos de la propuesta y los resultados de su implementación, que muestran logros significativos tanto en el aprendizaje disciplinar como en aspectos motivacionales relacionados con los recursos y las tareas propuestas

Shrub encroachment can reverse desertification in semi-arid Mediterranean grasslands

The worldwide phenomenon of shrub encroachment in grass-dominated dryland ecosystems is commonly associated with desertification. Studies of the purported desertification effects associated with shrub encroachment are often restricted to relatively few study areas, and document a narrow range of possible impacts upon biota and ecosystem processes. We conducted a study in degraded Mediterranean grasslands dominated by Stipa tenacissima to simultaneously evaluate the effects of shrub encroachment on the structure and composition of multiple biotic community components, and on various indicators of ecosystem function. Shrub encroachment enhanced vascular plant richness, biomass of fungi, actinomycetes and other bacteria, and was linked with greater soil fertility and N mineralization rates. While shrub encroachment may be a widespread phenomenon in drylands, an interpretation that this is an expression of desertification is not universal. Our results suggest that shrub establishment may be an important step in the reversal of desertification processes in the Mediterranean region.F.T.M. and M.A.B. were supported by ‘Ramón y Cajal’ and ‘Juan de la Cierva’ contracts from the Spanish MICINN (co-funded by the European Social Fund). F.T.M. was also supported by the British Ecological Society (ECPG 231/607 and Studentship 231/1975) and MICINN (CGL2008-00986-E/BOS project). This research was funded by grants from the Fundación BBVA (BIOCON06/105), Comunidad de Madrid (REMEDINAL, S-0505/AMB/0335), and Universidad Rey Juan Carlos (URJC-RNT-063-2).Peer reviewe

El texto multimodal de Física en la escuela secundaria: Propuesta de tareas de lectura

Los textos de ciencias, particularmente los de Física, se caracterizan por ser textos multimodales en los que interactúan (1) un sistema verbal, que constituye la expresión de significados basados en lo lingüístico, exclusivamente; (2) un sistema gráfico que posibilita la presentación de datos en formatos tales como fotografías, diagramas, tablas, entre otros; (3) un sistema matemático conformado por grupos de grafías, signos o representaciones que permiten que el significado sea codificado simbólicamente de forma sintética; y (4) un sistema tipográfico constituido por la forma, tamaño y color de las letras. Esto implica para el estudiante enfrentar dificultades diferentes de las que se le presentan cuando lee en otro contexto. En el marco de la Lingüística Sistémico‐Funcional, en este trabajo presentamos el análisis de un texto de Física extraído de un manual escolar de uso corriente en el nivel secundario con el objetivo de caracterizar esta compleja interacción entre los sistemas mencionados. Dicho análisis es el punto de partida para el diseño de tareas de lectura que capten los significados presentes en estos sistemas y sus relaciones. Consideramos que una propuesta de este tipo le ofrece al docente de ciencias un modo de evaluar críticamente el texto antes de su uso en el aula. A su vez, este análisis le ayudaría a plantear tareas que optimicen el proceso de lectura para que los estudiantes puedan superar los obstáculos y así favorecer la construcción del conocimiento escolar en ciencias en la escuela secundaria

The construct gender as a basis for categorizingscience texts in first and foreing languages

El constructo género implica un evento comunicativo, con propósitos identificados y comprendidos por los miembros de una comunidad profesional o académica. El género es así, una actividad orientada a un propósito, planteada en etapas con sus propias estructuras esquemáticas (Martin, 1992). Con el objetivo de: a) mostrar la importancia del constructo género desde la Lingüística Sistémico-Funcional (LSF), b) presentar una taxonomía de géneros de las ciencias, y c) reflexionar sobre la selección de textos en base a géneros, se planificó un taller en el marco del XVII Encuentro Plurilingüístico realizado en la Universidad Católica de Cuyo, San Juan, Argentina. Este artículo presenta el trabajo realizado con los docentes de lengua materna y extranjera que asistieron al mencionado taller.53-62anualThe construct genre implies a recognizable communicative event, characterized by some purposes which are identified by the members of a professional or academic community. Thus, genre is a staged goal oriented activity with its own schematic structures (Martin, 1992). With the aim of a) showing the importance of the construct genre in Systemic Functional Linguistics (SFL), b) presenting a taxonomy on genres of sciences, and c) reflecting on a genre based selection of texts, a workshop was planned for the XVII Encuentro Plurilingüístico carried out at Universidad Católica de Cuyo, San Juan, Argentina. This article describes the work done with the teachers of languages, both, native and foreign, who attended this conference

Data from: Shrub encroachment can reverse desertification in semi-arid Mediterranean grasslands

The worldwide phenomenon of shrub encroachment in grass-dominated dryland ecosystems is commonly associated with desertification. Studies of the purported desertification effects associated with shrub encroachment are often restricted to relatively few study areas, and document a narrow range of possible impacts upon biota and ecosystem processes. We conducted a study in degraded Mediterranean grasslands dominated by Stipa tenacissima to simultaneously evaluate the effects of shrub encroachment on the structure and composition of multiple biotic community components, and on various indicators of ecosystem function. Shrub encroachment enhanced vascular plant richness, biomass of fungi, actinomycetes and other bacteria, and was linked with greater soil fertility and N mineralization rates. While shrub encroachment may be a widespread phenomenon in drylands, an interpretation that this is an expression of desertification is not universal. Our results suggest that shrub establishment may be an important step in the reversal of desertification processes in the Mediterranean region

Data from: Shrub encroachment can reverse desertification in semi-arid Mediterranean grasslands

The worldwide phenomenon of shrub encroachment in grass-dominated dryland ecosystems is commonly associated with desertification. Studies of the purported desertification effects associated with shrub encroachment are often restricted to relatively few study areas, and document a narrow range of possible impacts upon biota and ecosystem processes. We conducted a study in degraded Mediterranean grasslands dominated by Stipa tenacissima to simultaneously evaluate the effects of shrub encroachment on the structure and composition of multiple biotic community components, and on various indicators of ecosystem function. Shrub encroachment enhanced vascular plant richness, biomass of fungi, actinomycetes and other bacteria, and was linked with greater soil fertility and N mineralization rates. While shrub encroachment may be a widespread phenomenon in drylands, an interpretation that this is an expression of desertification is not universal. Our results suggest that shrub establishment may be an important step in the reversal of desertification processes in the Mediterranean region

Environmental and soil data from encroached/unencroached Stipa tenacissima steppes from Spain

Environmental (coordinates, elevation, slope, aspect, mean annual rainfall and temperature) and soil (pH, organic carbon, total nitrogen, total phosphorus, soil respiration, potassium and nitrogen mineralization) variables at the microsite and site scales for Stipa tenacissima grasslands with and without sprouting shrubs in a gradient from central to southern Spain