Estudio de demandas de formación profesional para el desarrollo local y regional. Un estudio sectorial en la provincia de Entre Ríos

Este trabajo presenta, de manera sintética, los resultados de un estudio desarrollado durante el año 2005 en la provincia de Entre Ríos con el objeto de relevar los perfiles y competencias laborales requeridos en los distintos departamentos de la p rovincia, identificar demandas de capacitación y avanzar en la definición de ofertas de formación profesional y laboral que respondieran a dichas demandas. En primer lugar se realizan algunas consideraciones en torno a los fundamentos y enfoques posibles a aplicar a los análisis de mercados de trabajo locales. Luego, se presentan los instrumentos de relevamiento utilizados y se exponen y sistematizan los resultados obtenidos. Finalmente se presentan las conclusiones y se incluyen algunas recomendaciones que pueden derivarse a partir de dichos resultados. El contenido del mismo apunta a enriquecer el proceso de toma de decisiones en torno a la reconstrucción de la educación y al desarrollo productivo con base sustentable

Degradation in AlGaN/GaN heterojunction field effect transistors upon electrical stress: Effects of field and temperature

AlGaN/GaN heterojunction field effect transistors (HFETs) with 2 μm gate length were subjected to on-state-high-field (high drain bias and drain current) and reverse-gate-bias (no drain currentand reverse gate bias) stress at room and elevated temperatures for up to 10 h. The resulting degradation of the HFETs was studied by direct current and uniquely phase noise before and after stress. A series of drain and gate voltages was applied during the on-state-high-field and reverse-gate-bias stress conditions, respectively, to examine the effect of electric field on degradation of the HFET devices passivated with SiNx. The degradation behaviors under these two types of stress conditions were analyzed and compared. In order to isolate the effect of self-heating/temperature on device degradation, stress experiments were conducted at base plate temperatures up to 150 °C. It was found that the electric field induced by reverse-gate-bias mainly generated trap(s), most likely in the AlGaN barrier, which initially were manifested as generation-recombination (G-R) peak(s) in the phase noise spectra near 103 Hz. Meanwhileelectric field induced by on-state-high-field stress mainly generated hot-electron and hot-phonon effects, which result in a nearly frequency independent increase of noise spectra. The external base plate temperatures promote trap generation as evidenced by increased G-R peak intensities

Field-tuned order by disorder in frustrated Ising magnets with antiferromagnetic interactions

We demonstrate the appearance of thermal order by disorder in Ising pyrochlores with staggered antiferromagnetic order frustrated by an applied magnetic field. We use a mean-field cluster variational method, a low-temperature expansion, and Monte Carlo simulations to characterize the order-by-disorder transition. By direct evaluation of the density of states, we quantitatively show how a symmetry-broken state is selected by thermal excitations. We discuss the relevance of our results to experiments in 2D and 3D samples and evaluate how anomalous finite-size effects could be exploited to detect this phenomenon experimentally in two-dimensional artificial systems, or in antiferromagnetic all-in-all-out pyrochlores like Nd2Hf2O7 or Nd2Zr2O7, for the first time.Publisher PDFPeer reviewe

Study of the light-induced metal-insulator transition in SrTiO3 by photoresistance spectroscopy

Photoresistivity and its spectral response has been systematically studied in oxygen deficient SrTiO3 single crystals for a wide range of resistivities, ρ, and carrier densities, n. At roomtemperature we have found a persistent photoresistance that gradually decreases as ρ is diminished or n is increased in addition to relaxation times of seconds to a few minutes suggesting that trapping of carriers is playing a major role. An analysis of the photoresistance excitation spectra shows two distinctive features that are related to the indirect gap of SrTiO3 at (3.25 ± 0.04) eV and to a direct transition at (3.40 ± 0.03) eV. The photoresistive crystals present a temperature dependent resisitivity under illumination that experiences a metal-insulator transition below T ∼ 85 K. Lowtemperature photoresistance spectrum reveals as a suitable technique to understand the origin of this transition, pointing to an enhanced efficiency of the ∼ 3.25 eV gap to promote electrons to the bottom of the conduction band.Fil: Bridoux, German. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Villafuerte, Manuel Jose. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferreyra, J. M.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Bachi, N.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Figueroa, C. A.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Heluani, S. P.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentin

Field-tuned order by disorder in frustrated ising magnets with antiferromagnetic interactions

We demonstrate the appearance of thermal order by disorder in Ising pyrochlores with staggered antiferromagnetic order frustrated by an applied magnetic field. We use a mean-field cluster variational method, a low-temperature expansion, and Monte Carlo simulations to characterize the order-by-disorder transition. By direct evaluation of the density of states, we quantitatively show how a symmetry-broken state is selected by thermal excitations. We discuss the relevance of our results to experiments in 2D and 3D samples and evaluate how anomalous finite-size effects could be exploited to detect this phenomenon experimentally in two-dimensional artificial systems, or in antiferromagnetic all-in-all-out pyrochlores like Nd2Hf2O7 or Nd2Zr2O7, for the first time.Facultad de Ciencias ExactasInstituto de Física de Líquidos y Sistemas Biológico

Communicative interaction in natural sciences lessons. A didactic analysis based on discursive circuits

En este trabajo se discute el rol de la comunicación en el aula de ciencias y se delimita una forma de análisis relacionada con circuitos de interacción discursiva. Se comparan tres tipos de circuitos para clases de ciencias experimentales: exposición abierta, diálogo guiado e indagación dialógica problematizadora. Los datos resumen los registros de un grupo de investigaciones interpretativas desarrolladas por el equipo en los últimos diez años, las cuales analizan el diálogo asociado a temas de ciencias y ciclos de actividad. Se presenta la escala de análisis resultante y los tipos de secuencia de intervenciones de docentes y alumnos. Desde las mismas se modelizan circuitos de comunicación que van desde la clase tradicional a una constructivista.Se concluye respecto a la necesidad de incluir la problemática de la comunicación en el aula a lo largo de la práctica educativa y de los procesos de formación docente, haciéndola formar parte tanto del diseño, como del desarrollo y evaluación de la tarea docente.This work argues the role of communication in natural sciences classrooms and delimits a way of analysis in relation to interactive discursive circuits. Three types of circuits for experimental sciences lessons are compared: open exposition, guided dialog and problematic dialogic inquiry. The data summary the records of a group of interpretative research developed by the team in the last years ten years, which analyses the dialogue associated with science topics and cycles of activity. The resulting scale of analysis and types of intervention sequences held by teachers and students are presented. Based on them, communication circuits are modeled ranging from the traditional classroom to a constructivist one. It is concluded in relation to the need of including the problem of communication in the classroom throughout the educational practice and the processes of teacher training, making it part of the design, development and evaluation of the teaching task