Materiales biodegradables en base a proteínas de soja y montmorillonitas

Entre los biomateriales, las proteínas de soja tienen la capacidad de formar películas comestibles y/o biodegradables. Respecto de los polímeros sintéticos, estas películas proteicas presentan excelentes propiedades barrera a gases, lípidos y aromas; pero comúnmente no muestran propiedades mecánicas y barrera al vapor de agua satisfactorias para aplicaciones prácticas. Con el fin de mejorar la funcionalidad de estas películas, en este trabajo se estudió la obtención de materiales nanocompuestos, amigables con el medio ambiente, a partir de proteínas de soja y montmorillonitas (MMT) con potencial aplicación como envases de alimentos o como adhesivos.Documento embargado hasta el 31 de marzo de 2014.Facultad de Ciencias Exacta

Can a Soil Mineralization Test Improve Wheat and Corn Nitrogen Diagnosis?

A network of field studies determined that the traditional method for predicting soil N availability …a pre-plant nitrate test … can be combined with an indicator of soil N mineralization capacity to significantly improve the diagnosis for soil N availability for both wheat and corn.Fil: Reussi Calvo, Nahuel Ignacio. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Laboratiorio de Suelos. Fertilab; ArgentinaFil: Echeverría, Hector E.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Sainz Rozas, Hernan Rene. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Berardo, Angel. Laboratiorio de Suelos. Fertilab; ArgentinaFil: Diovisalvi, Natalia. Laboratiorio de Suelos. Fertilab; Argentin

Enseñar a aprender: ¿ejercicios o problemas?

Tomando como ejemplo una clase de matemáticas, en este artículo se propone la solución de problemas como uno de los métodos de enseñar a aprender. Para que esta enseñanza sea efectiva tiene que partir de tareas poco rutinarias que planteen alguna dificultad a los alumnos y los obliguen a reflexionar sobre los objetivos y los procedimientos que ponen en marcha, aprendiendo a planificar, supervisar y evaluar su propio aprendizaje. Los profesores deben guiar ese aprendizaje para evitar que los estudiantes se pierda

Citizen security and urban commuting in Latin America

Sustainable modes of transport, including both public transit and active transport, have been promoted as strategies to reduce greenhouse gas emissions. However, one factor that may influence their use is related to security concerns, although prior evidence on this topic is scarce and inconclusive. We explore whether perceived security in 10 large cities in Latin America is related to mode choice for commuting. We rely on the 2017 CAF Survey implemented by the Development Bank of Latin America, where individuals report their levels of satisfaction with neighbourhood security. Our results suggest that individuals who feel more satisfied with their neighbourhood security engage in more public transit commuting, although this result holds only for male commuters. Our results suggest that strategies aimed at increasing security can alleviate concerns about neighbourhood crime, increasing the use of public transit in Latin America

Active commuting and the health of workers

Research has shown that commuting is related to the health of workers, and that mode choice may have differential effects on this relationship. We analyze the relationship between commuting by different modes of transport and the health status reported by US workers, using the 2014-2016 Eating and Health (EH) Module of the American Time Use Survey (ATUS). We estimate Ordinary Least Squares models on a measure of subjective health, that is the self-reported assessment of individual general health status, and on the body mass index. We find that longer commutes by bicycle are significantly related to higher levels of subjective health and to lower body mass index, while commuting by walking is weakly related to both health measures. We test the robustness of our results to possible measurement errors in commuting times, to the exclusion of compensating factors, and to the estimation method. We additionally instrument individual use of bicycles with an indicator of individual green attitudes, based on the General Social Survey (GSS), and the results consistently show that individuals who commute longer by bicycle report better subjective health and lower body mass index. Our results may help policy makers in evaluating the importance of having infrastructures that facilitate the use of bicycles as a means of transport, boosting investment in these infrastructures, especially in large cities.Fil: Echeverría, Lucía. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Gimenez-Nadal, J. Ignacio. University of Zaragoza. EDIS; Spain.Fil: Molina, josé Alberto. University of Zaragoza. EDIS; Spain

Carpooling: User profiles and well-being

Carpooling is a sustainable daily mobility mode, implying significant reductions in energy consumption and CO2 emissions, although it remains an uncommon practice. With the aim of stimulating this green transportation mode, this paper focus on understanding why certain individuals will agree to share a car to a common destination, apart from the obvious environmental benefit in emissions. It first describes the profile of users and then explores the relationship between this transportation mode and the participants' well- being. To that end, we have selected two countries, the UK and the US, where the use of cars represents a high proportion of daily commuting. We use the UK Time Use Survey (UKTUS) from 2014-2015 and the Well-Being Module of the American Time Use Survey (ATUS) from 2010-2012-2013 to identify which groups in the population are more likely to pool their cars, and with whom those individuals enjoy carpooling more. Results indicate that individuals with certain socio-demographic characteristics and occupations are more likely to commute by carpooling, but the profile seems to be country-specific. Furthermore, our evidence reveals a positive relationship between carpooling and well-being during commuting.Fil: Echeverría, Lucía. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Gimenez-Nadal, J. Ignacio. University of Zaragoza. EDIS; Spain.Fil: Molina, josé Alberto. University of Zaragoza. EDIS; Spain

Active commuting and the health of workers

Introduction: Research has shown that commuting is related to the health of workers, and that mode choice may have a range of effects on this relationship. We analyze the relationship between active commuting (walking and cycling) and the health status reported by US workers. Methods: We use the 2014-2016 Eating and Health (EH) Module of the American Time Use Survey (ATUS). We estimate Ordinary Least Squares models on a measure of subjective health that is the self-reported assessment of individual general health status, and on the body mass index. Results: longer commutes by bicycle are significantly related to higher levels of subjective health and to lower body mass index, while commuting by walking is only weakly related to both health measures. We test the robustness of our results to possible measurement error in commuting times, to the exclusion of compensating factors, to the estimation method, and to the inclusion of time devoted to leisure-based physical activities. Conclusions: Our results may help policy makers in evaluating the importance of infrastructures that facilitate the use of bicycles as a means of transport, boosting investment in these infrastructures, especially in larger cities.Fil: Echeverría, Lucía. CONICET; Argentina.Fil: Gimenez-Nadal, J. Ignacio. University of Zaragoza. EDIS; Spain.Fil: Molina, josé Alberto. University of Zaragoza. EDIS; Spain

Green mobility and well-being

Recent years have witnessed efforts worldwide to promote green mobility, aimed at boosting sustainable economic growth. However, how green mobility relates to travelers' well-being remains an open question. We explore whether "green" modes of transportation (public transit and walking/cycling) are associated with higher levels of well-being in comparison to private driving, placing special focus on different types of travel (related to paid work, unpaid work, personal care, childcare, and leisure). We use the UK Time Use Survey (UKTUS) from 2014-2015, and exploit information on self-reported enjoyment during travel, as a measure of experienced well-being. We estimate Ordinary Least Squares and Random Effects regressions for each travel category, and find relative, positive effects of physical transport on enjoyment, in terms of personal care and leisure, while the relative negative effects of public transport are observed for childcare and work/paid travel, in relationship to traditional driving modes. Our evidence suggests a need to develop strategies to effectively promote mobility by physical modes, while improving the experience of public transit users.Fil: Echeverría, Lucía. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Gimenez-Nadal, J. Ignacio. University of Zaragoza. EDIS; Spain.Fil: Molina, josé Alberto. University of Zaragoza. EDIS; Spain

In search of lost constructivism: implicit conceptions on learning

The Version of Record of this manuscript has been published and is available in Estudios de Psicología 2001 http://www.tandfonline.com/10.1174/021093901609479El punto de partida de este trabajo ha sido analizar los diferentes significados atribuidos al término constructivismo y las concepciones implícitas subyacentes sobre el aprendizaje y la enseñanza. De la misma manera que existe cierta confusión en la utilización de este término por psicólogos, educadores y otros académicos, también parece haber cierta confusión y una excesiva atribución de características constructivistas a distintas concepciones sobre el aprendizaje y la adquisición de conocimientos. Una manera de analizar las diferencias tanto entre estas teorías científicas como en las personales es analizar los supuestos epistemológicos, ontológicos y causales que subyacen a los distintos tipos de teorías. La búsqueda de las características constructivistas y de los métodos que permitan diferenciar un tipo de teorías de otros nos sirve de guía en este artículo para una revisión de los trabajos sobre concepciones del aprendizajeThe study first analyses the different meanings attributed to ‘constructivism’ together with implicit conceptions underlying teaching and learning. We argue that just as there is certain confusion in the way psychologists, educators, and other academic persons use this term, likewise there is certain confusion and an excessive attribution of constructivist characteristics to different conceptions of learning and knowledge acquisition. Differences both between these scientific theories and personal theories may be analysed by examining epistemological, ontological and conceptual presuppositions underlying the different types of theories. The present review is organised along two axes: searching for constructivist characteristics and methods that will allow us to distinguish between different kinds of learning and teaching conceptionsEste trabajo ha sido posible gracias al apoyo de la D.G.I.C.Y.T. al proyecto P.B 98-0095 de cuyo equipo investigador forman parte los 3 primeros autores y del C.O.N.I.C.E.T. al proyecto PEI 017/98 del que forma parte la última autora. Asimismo la versión final de este trabajo se ha visto enriquecida por las sugerencias aportadas por los miembros de la Red ALFA subvencionada por la Comisión Europea mediante el contrato ALR/B7-3011/94-5.0157.8 a un proyecto coordinado desde la Facultad de Psicología de la UAM, y del que forman parte los cuatro autore