Search results for "EDUCA"
showing 10 items of 30201 documents
Influence of the MgO barrier thickness on the lifetime characteristics of magnetic tunnelling junctions for sensors
2016
Magnetic tunnelling junctions increasingly enter the market for magnetic sensor applications. Thus, technological parameters such as the lifetime characteristics become more and more important. Here, an analysis of the lifetime characteristics of magnetic tunnelling junctions using the Weibull statistical distribution for CoFeB/MgO/CoFeB junctions is presented. The Weibull distribution is governed by two parameters, the characteristic lifetime η of the population and the shape parameter β, which gives information about the presence of an infant mortality. The suitability of the Weibull distribution is demonstrated for the description of dielectric breakdown processes in MgO-based tunnelling…
Light-induced nonthermal population of optical phonons in nanocrystals
2017
Raman spectroscopy is widely used to study bulk and nanomaterials, where information is frequently obtained from spectral line positions and intensities. In this study, we monitored the Raman spectrum of ensembles of semiconductor nanocrystals (NCs) as a function of optical excitation intensity (optical excitation experiments). We observe that in NCs the red-shift of the Raman peak position with increasing light power density is much steeper than that recorded for the corresponding bulk material. The increase in optical excitation intensity results also in an increasingly higher temperature of the NCs as obtained with Raman thermometry through the commonly used Stokes/anti-Stokes intensity …
El pensamiento espontáneo docente sobre la ciencia y su enseñanza
2018
<span>En las dos últimas décadas la investigación en didáctica de las ciencias ha centrado su atención en el aprendizaje y, en particular, se ha caracterizado por haber estudiado en profundidad el conocimiento inicial de los estudiantes en muy diversos dominios de las ciencias. Desde hace pocos años el énfasis está derivado -y cada vez con mayor interés- hacia el estudio de la enseñanza y, en particular, hacia el de su principal artífice: el profesorado.</span>
Sostenibilidad y laboratorios escolares
2018
<span>Actualmente no es ninguna exageración afirmar que estamos viviendo una situación de verdadera emergencia planetaria, marcada por toda una serie de graves problemas estrechamente relacionados entre sí, tales como: superpoblación, contaminación, agotamiento de recursos naturales, cambio climático, pérdida de biodiversidad, lluvia ácida y destrucción de la capa de ozono. Dichos problemas, lejos de disminuir, son cada vez más intensos y extienden su impacto sobre todo el planeta. Así, en cuanto al calentamiento global, se afirma que la gravedad es tal, que si no se pone freno antes de una decena de años, después será ya demasiado tarde (Gore, 2007).</span>
La motivación de los estudiantes y la enseñanza de la Química. Una cuestión controvertida
2018
<span>El tema de la motivación de los estudiantes hacia el aprendizaje de cualquier materia científica constituye una seria preocupación para el profesorado. En primer lugar, porque los docentes constatan una falta general de interés de los alumnos hacia las disciplinas científicas como la Física y la Química. Esta percepción ha sido corroborada por los propios estudiantes en diferentes trabajos de investigación. En efecto, los propios estudiantes señalan como principales causantes de su actitud desfavorable, de su desinterés hacia la ciencia y su aprendizaje, a la enseñanza de una ciencia descontextualizada...</span>
Dificultades para la incorporación a la enseñanza de los hallazgos de la investigación e innovación en didáctica de las ciencias
2018
<span>La importancia social concedida, desde hace ya décadas, a la educación científica (Dewey 1916; Langevin, 1926) ha ido creciendo y ha experimentado, últimamente, un cambio cualitativo. En efecto, la tradicional importancia concedida a las inversiones en educación científica y tecnológica, para hacer posible el desarrollo futuro de un país, ha dejado paso al convencimiento de que la alfabetización científica de todos los ciudadanos y ciudadanas ha pasado a constituir una exigencia urgente, un requisito también para el desarrollo inmediato.</span>
Elucidating the Influence of the Activation Energy on Reaction Rates by Simulations Based on a Simple Particle Model
2020
An application for visualizing the dynamic properties of an equimolar binary mixture of isotropic reactive particles is presented. By introducing a user selectable choice for the activation energy, the application is useful to demonstrate qualitatively that the reaction rate depends on the above choice and on temperature. The application is based on a 2D realistic dynamic model where atoms move because of their thermal energies and the trajectories are determined by solving numerically Newton’s laws according to a Molecular Dynamics (MD) scheme. Collisions are monitored as time progresses, and every time the collision energy is larger than the selected activation energy, a reactive event oc…
Analysis of salivary detection of P16INK4A and RASSF1A promoter gene methylation and its association with oral squamous cell carcinoma in a Colombian…
2019
Background Epigenetic factors play a fundamental role in the etiopathogenesis of oral squamous cell carcinoma (OSCC). This study evaluated if salivary detection of P16INK4A/RASSF1A gene promoter methylation might be linked to the clinical/histological features of OSCC in a Colombian population. Material and Methods Methylation-specific polymerase chain reaction (MSP-PCR) was used to detect the methylation frequency of P16INK4A/RASSF1A genes in DNA obtained from whole saliva collected of 40 healthy controls (HC) and 43 OSCC patients. Determination of the clinical performance of MSP-PCR assay was based on standard algorithms derived from two-way contingency table analysis. The association of …
Social Representations of Flooding of Future Teachers of Primary Education (Social Sciences): A Geographical Approach in the Spanish Mediterranean Re…
2020
The risk of flooding is the main natural hazard that affects the European Mediterranean region. This hazard has worsened in recent decades due to the occupation of flood areas and the effects of climate change. Therefore, understanding and gaining a more in-depth knowledge of social representations of flooding is important. In addition, interest in this subject is accentuated in the case of future teachers. This is because it is mandatory to teach this subject in Primary Education (Grades 1&ndash
Projecting Exposure to Extreme Climate Impact Events Across Six Event Categories and Three Spatial Scales
2020
Summarization: The extent and impact of climate‐related extreme events depend on the underlying meteorological, hydrological, or climatological drivers as well as on human factors such as land use or population density. Here we quantify the pure effect of historical and future climate change on the exposure of land and population to extreme climate impact events using an unprecedentedly large ensemble of harmonized climate impact simulations from the Inter‐Sectoral Impact Model Intercomparison Project phase 2b. Our results indicate that global warming has already more than doubled both the global land area and the global population annually exposed to all six categories of extreme events co…