Utilización de textos y gráficos en la enseñanza asistida por ordenador

Se realiza un análisis de los aspectos que rigen la utilización de textos, gráficos y animaciones en el desarrollo de materiales didácticos orientados a la Enseñanza Asistida por Ordenador, con el objetivo de obtener mayor eficiencia y calidad en la confección de lecciones. Se destaca la importancia de la imagen y el texto durante el proceso de aprendizaje y se analiza la posibilidad de combinar el ordenador con sistemas electrónicos que aumentan su potencialidad y constituyen nuevas vías de interacción con el estudiante

Utilización de textos y gráficos en la Enseñanza Asistida por Ordenador

Se realiza un análisis de los aspectos que rigen la utilización de textos, gráficos y animaciones en el desarrollo de materiales didácticos orientados a la Enseñanza Asistida por Ordenador, con el objetivo de obtener mayor eficiencia y calidad en la conf

Conceptual Maps: A Resource for the Supported Learning in Technologies

Se describen las características fundamentales de los mapas conceptuales, se resalta su importancia como instrumento para la organización y sistematización de ideas y conocimientos y se ofrecen propuestas para su elaboración, especialmente vinculándolos al diseño y producción de materiales didácticos que sirvan de apoyo a diferentes modalidades de aprendizaje apoyadas en las tecnologías de la información y la comunicación.This paper describes the fundamental characteristics of conceptual maps, highlights its importance as an instrument for organization and sistematization of ideas and knowledge, and makes proposals for its construction, specially in connection with the design and production of educational stuff aimed at several information-technology supported learning modalities

The role of the synchrotron component in the mid infrared spectrum of M 87

We study in detail the mid-infrared Spitzer-IRS spectrum of M 87 in the range 5 to 20 micron. Thanks to the high sensitivity of our Spitzer-IRS spectra we can disentangle the stellar and nuclear components of this active galaxy. To this end we have properly subtracted from the M 87 spectrum, the contribution of the underlying stellar continuum, derived from passive Virgo galaxies in our sample. The residual is a clear power-law, without any additional thermal component, with a zero point consistent with that obtained by high spatial resolution, ground based observations. The residual is independent of the adopted passive template. This indicates that the 10 micron silicate emission shown in spectra of M 87 can be entirely accounted for by the underlying old stellar population, leaving little room for a possible torus contribution. The MIR power-law has a slope alpha ~ 0.77-0.82 (S$_\nu\propto\nu^{-\alpha}$), consistent with optically thin synchrotron emission.Comment: 5 pages, 4 figures, accepted for publication in ApJ main journa

Radon, water chemistry and pollution check by volatile organic compounds in springs around Popocatepetl volcano, Mexico

Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs were analysed as a function of the 2002-2003 volcanic activity. The measurements of soil radon indicated fluctuations related to both the meteorological and sporadic explosive events. Groundwater radon showed essential differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed also stability along the monitoring period. No anthropogenic pollution from Volatile Organic Compounds (VOCs) was observed. An overview of the soil radon behaviour as a function of the volcanic activity in the period 1994-2002 is also discussed

Disentangling environmental correlates of vascular plant biodiversity in a Mediterranean hotspot

We determined the environmental correlates of vascular plant biodiversity in the Baetic-Rifan region, a plant biodiversity hotspot in the western Mediterranean. A catalog of the whole flora of Andalusia and northern Morocco, the region that includes most of the Baetic-Rifan complex, was compiled using recent comprehensive floristic catalogs. Hierarchical cluster analysis (HCA) and detrended correspondence analysis (DCA) of the different ecoregions of Andalusia and northern Morocco were conducted to determine their floristic affinities. Diversity patterns were studied further by focusing on regional endemic taxa. Endemic and nonendemic alpha diversities were regressed to several environmental variables. Finally, semi-partial regressions on distance matrices were conducted to extract the respective contributions of climatic, altitudinal, lithological, and geographical distance matrices to beta diversity in endemic and nonendemic taxa. We found that West Rifan plant assemblages had more similarities with Andalusian ecoregions than with other nearby northern Morocco ecoregions. The endemic alpha diversity was explained relatively well by the environmental variables related to summer drought and extreme temperature values. Of all the variables, geographical distance contributed by far the most to spatial turnover in species diversity in the Baetic-Rifan hotspot. In the Baetic range, elevation was the most significant driver of nonendemic species beta diversity, while lithology and elevation were the main drivers of endemic beta diversity. Despite the fact that Andalusia and northern Morocco are presently separated by the Atlantic Ocean and the Mediterranean Sea, the Baetic and Rifan mountain ranges have many floristic similarities – especially in their western ranges – due to past migration of species across the Strait of Gibraltar. Climatic variables could be shaping the spatial distribution of endemic species richness throughout the Baetic-Rifan hotspot. Determinants of spatial turnover in biodiversity in the Baetic-Rifan hotspot vary in importance between endemic and nonendemic species

Reemergence of dengue in Cuba: a 1997 epidemic in Santiago de Cuba.

After 15 years of absence, dengue reemerged in the municipality of Santiago de Cuba because of increasing migration to the area by people from disease-endemic regions, a high level of vector infestation, and the breakdown of eradication measures. The 1997 epidemic was detected early through an active surveillance system. Of 2,946 laboratory-confirmed cases, 205 were dengue hemorrhagic fever, and 12 were fatal. No deaths were reported in persons under 16 years of age. Now the epidemic is fully controlled

Synthesis, cytotoxicity, DNA interaction and cell cycle studies of trans-diiodophosphine Pt(ii) complexes

Platinum complexes, bearing aliphatic amines and phosphine ligands in trans configuration with iodide as leaving groups, are synthesized and characterized. The crystal structure of trans-PtI2(isopropylamine)(PPh3) is reported. The complex bearing isopropylamine is demonstrated to be the best candidate as its cytotoxic activity is comparable to or better than cisplatin. A remarkably higher interaction of the complexes with DNA is reported as compared to the parent chlorido series. Cell cycle studies of the complexes in six human cell lines are performed and also compared with the previous seriesThe Spanish Ministerio de Economia y Competitividad has supported this work with the grant: SAF2012-34424. This work was also supported by a School of the Sciences, Stevenson University Seed Gran

Nanospintronics with carbon nanotubes

One of the actual challenges of spintronics is the realization of a spin-transistor allowing to control spin transport through an electrostatic gate. In this review, we report on different experiments which demonstrate a gate control of spin transport in a carbon nanotube connected to ferromagnetic leads. We also discuss some theoretical approaches which can be used to analyze spin transport in these systems. We emphasize the roles of the gate-tunable quasi-bound states inside the nanotube and the coherent spin-dependent scattering at the interfaces between the nanotube and its ferromagnetic contacts.Comment: 35 pages, 15 figures, some figures in gi

Electric-dipole active two-magnon excitation in {\textit{ab}} spiral spin phase of a ferroelectric magnet Gd0.7_{\textbf{0.7}}Tb0.3_{\textbf{0.3}}MnO3_{\textbf 3}

A broad continuum-like spin excitation (1--10 meV) with a peak structure around 2.4 meV has been observed in the ferroelectric $ab$ spiral spin phase of Gd$_{0.7}$Tb$_{0.3}$MnO$_3$ by using terahertz (THz) time-domain spectroscopy. Based on a complete set of light-polarization measurements, we identify the spin excitation active for the light $E$ vector only along the a-axis, which grows in intensity with lowering temperature even from above the magnetic ordering temperature but disappears upon the transition to the $A$-type antiferromagnetic phase. Such an electric-dipole active spin excitation as observed at THz frequencies can be ascribed to the two-magnon excitation in terms of the unique polarization selection rule in a variety of the magnetically ordered phases.Comment: 11 pages including 3 figure