Search

This work evaluates the effectiveness of an instructional design focused on solving mathemat-ical problems through the experimentation and use of manipulative materials, focused on redirecting fu-ture teachers’ perceptions of mathematics towards more positive beliefs and reactions. The design was pre-experimental with a pretest posttest group, and the sample is made up of 91 students of the Primary and Infant Education Teacher degree, who were studying the Mathematics Teaching course. The instru-ment used is a previously validated self-report instrument on beliefs, emotions and attitudes about math-ematics. The instructional design has had a positive impact, since it has generated significant changes on their beliefs about the characteristics of the teacher, their attitudes and emotional reactions towards mathematics, and on their level of self-confidence and assurance as a future teacher capable of imple-menting procedures with the goal of solving mathematical problems in the context of the classroom., En este trabajo se evalúa la eficacia de un proceso de formación basado en la resolución de problemas matemáticos mediante la experimentación y el uso de materiales manipulativos, sobre el do-minio afectivo, definido como creencias, emociones y actitudes hacia las matemáticas de futuros maestros. Se ha utilizado un diseño preexperimental con grupo pretest y postest sobre una muestra de 91 estudiantes de los grados en Maestro en Educación Infantil y Primaria. El instrumento utilizado es un autoinforme so-bre creencias, emociones y actitudes acerca de las matemáticas validado previamente. El diseño de ins-trucción ha incidido de forma positiva en el dominio afectivo, pues ha generado cambios significativos en sus creencias acerca de la naturaleza de las matemáticas y de su enseñanza y aprendizaje, del papel del docente, de ellos mismos como aprendices de matemáticas y en sus actitudes y emociones, pues muestran un mayor interés, satisfacción y seguridad como futuros maestros.

La competencia digital docente y su perfeccionamiento cobran un papel destacado en el contexto educativo actual. En las áreas STEM, uno de los principales recursos digitales para promover eficazmente el conocimiento de las ciencias y desarrollar habilidades de indagación son las simulaciones virtuales, cobrando gran importancia el papel del docente en su uso eficiente en el aula. El objetivo de este trabajo es determinar la percepción de la competencia digital docente en el uso de simulaciones virtuales, así como analizar posibles diferencias frente a variables sociodemográficas, de uso y de formación. Se ha realizado un estudio cuantitativo mediante análisis descriptivo, correlacional y asociativo, con 500 docentes de áreas STEM de Educación Secundaria. Los resultados apuntan a una autopercepción media en las diferentes dimensiones de la competencia. No se obtienen diferencias significativas en genero, edad, años de experiencia docente, ni formación recibida, pero sí respecto al área de conocimiento en la que imparte clase, a la frecuencia de uso de esta tecnología en sus clases y a la necesidad de formación percibida. Se concluye que existe una necesidad de formación importante en el uso de simulaciones virtuales, destacando principalmente la formación en la búsqueda y selección de simulaciones adecuadas., Teacher digital competence and its improvement play a prominent role in the current educational context. Virtual simulations are one of the main digital resources for effectively learning science and developing inquiry skills in STEM areas, being essential the role of the teacher in their efficient use in the classroom. The objectives of this work are to measure the perception of teaching digital competence in the use of virtual simulations, as well as to analyze the results based on sociodemographic, use and training variables. A quantitative study has been carried out through descriptive, correlational and associative analysis, with 500 STEAM teachers of Secondary Education. The results show an average self-perception value in the different dimensions of the competence. No significant differences were found in gender, age, years of teaching experience, or training received, but there were differences regarding their knowledge area, the frequency of use of virtual simulations in class, and the perceived need for training. It is concluded that there is a need for significant training in the use of virtual simulations, mainly highlighting training in the search and selection of appropriate simulations.

This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty order of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity from the smallest (diatomic) molecules to clusters and nanoparticles. Combining some of these techniques opens up new avenues to unravel hitherto unexplored reaction pathways and mechanisms, and to establish their significance in, e.g. radiotherapy and radiation damage on the nanoscale, astrophysics, astrochemistry and atmospheric science.

Correction to: Nature Communications https://doi.org/10.1038/s41467-017-02437-9, published online 22 December 2017

The toolbox for imaging molecules is well-equipped today. Some techniques visualize the geometrical structure, others the electron density or electron orbitals. Molecules are many-body systems for which the correlation between the constituents is decisive and the spatial and the momentum distribution of one electron depends on those of the other electrons and the nuclei. Such correlations have escaped direct observation by imaging techniques so far. Here, we implement an imaging scheme which visualizes correlations between electrons by coincident detection of the reaction fragments after high energy photofragmentation. With this technique, we examine the H2 two-electron wave function in which electron–electron correlation beyond the mean-field level is prominent. We visualize the dependence of the wave function on the internuclear distance. High energy photoelectrons are shown to be a powerful tool for molecular imaging. Our study paves the way for future time resolved correlation imaging at FELs and laser based X-ray sources.

We present an analytical model based on the time-dependentWKB approximation to reproduce the photoionization spectra of anH2 molecule in the autoionization region.Weexplore the nondissociative channel, which is the major contribution after one-photon absorption, and we focus on the features arising in the energy differential spectra due to the interference between the direct and the autoionization pathways. These features depend on both the timescale of the electronic decay of the autoionizing state and the time evolution of the vibrational wavepacket created in this state. With full ab initio calculations and with a one-dimensional approach that only takes into account the nuclear wavepacket associated to the few relevant electronic states we compare the ground state, the autoionizing state, and the background continuum electronic states. Finally, we illustrate how these features transform from molecular-like to atomic-like by increasing the mass of the system, thus making the electronic decay time shorter than the nuclear wavepacket motion associated with the resonant state. In other words, autoionization then occurs faster than the molecular dissociation into neutrals., Consejo Superior de Investigaciones Científicas http://dx.doi.org/10.13039/501100003339, European Research Council http://dx.doi.org/10.13039/501100000781, Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266, European Cooperation in Science and Technology http://dx.doi.org/10.13039/501100000921, Computer time from the CCC-UAM and Mare Nostrum Superconduct or Centers, Peer Reviewed

The INhibitor of Growth (ING) family of tumor suppressors regulates the transcriptional state of chromatin by recruiting remodeling complexes to sites with histone H3 trimethylated at position K4 (H3K4me3). This modification is recognized by the plant homeodomain (PHD) present at the C-terminus in the five members of the ING family. ING4 facilitates histone H3 acetylation by the HBO1 complex. Here, we show that ING4 forms homodimers through its N-terminal domain, which folds independently into an elongated coiled-coil structure. The central region of ING4, which contains the nuclear localization sequence, is disordered and flexible and does not directly interact with p53, or does it with very low affinity, in contrast to previous findings. The NMR analysis of the full-length protein reveals that the two PHD fingers of the dimer are chemically equivalent and independent of the rest of the molecule. The detailed NMR analysis of the full-length dimeric protein binding to histone H3K4me3 shows essentially the same binding site and affinity as the isolated PHD finger. Therefore, the ING4 dimer has two identical and independent binding sites for H3K4me3 tails, which, in the context of the chromatin, could belong to the same or to different nucleosomes. These results show that ING4 is a bivalent reader of the chromatin H3K4me3 modification and suggest a mechanism for enhanced targeting of the HBO1 complex to specific chromatin sites. This mechanism could be common to other ING-containing remodeling complexes. © 2009 Elsevier Ltd.