Análisis temporal de una base de datos de preguntas de autoevaluación para el aprendizaje de un lenguaje de programación.

Número especial dedicado al VII Simposio Pluridisciplinar sobre Diseño y Evaluación de Contenidos Digitales Educativos (SPDECE 2010).Resumen basado en el de la publicación

La estructura temporal de la experiencia de sensibilidad materna : su efecto sobre el desarrollo cognitivo y emocional infantil.

Resumen basado en el de la publicación

Modelo explicativo del efecto de los enfoques de aprendizaje sobre el rendimiento y el papel modulador de la dedicaci??n temporal

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A la llum de les matrius: projecte d'exposició temporal

El treball presenta el projecte d'una exposició temporal al Museu d'Art sobre el fons de xilografies procedents de la Impremta Carreras

Threshold adaptation, temporal integration and frequency discrimination-learning in hearing impaired children

This paper is a review of a study to evaluate the usefulness of a laboratory approach to auditory training with hearing impaired children.

Cross-modality temporal resolution for auditory, vibrotactile, and visual stimuli

This paper reviews a study of cross-modalities and within-modalities and their effects on speech perception.

Temporal processing in listeners with unilateral hearing loss

Temporal processing is examined for sounds delivered to the intact ear of individuals with unilateral hearing, and delivered to one ear of individuals with normal, bilateral hearing. Two temporal processing skills are assessed: 1) the ability to detect sinusoidal amplitude modulation of a wide-band noise, for various modulation frequencies, and 2) the just-noticeable-difference for temporal complexity of random-spectrogram-sounds.

Genetic and temporal aspects of protection by kanamycin against cochlear noise injury

Experiments explored the minimal kanamycin dosing regimen that renders protection against noise induced hearing loss in young CBA/J mice. We also tested the age-dependence of protection in CBA/J as well as the dependence of protection on a particular genetic background in experiments using young C57BL/6J and CBA/CaJ mice.

La tributación interna aplicada al arrendamiento mercantil y en el Régimen Especial de Admisión Temporal

La presente investigación tiene por objeto analizar el manejo tributario de los arrendamientos mercantiles y del régimen especial de admisión temporal. Se analiza la evolución del Leasing, determinando que el Ecuador fue uno de los primeros países en Latinoamérica en regular el Leasing; sin embargo, esta normativa no ha evolucionado, por lo que se examina la normativa tributaria vigente. Los Arrendamientos Mercantiles Financieros, permiten el financiamiento del 100% de los bienes de capital, opera a través de un contrato, en donde una compañía autorizada o una institución del sistema financiero, adquiere un bien de capital de acuerdo a las características especificadas por el arrendatario, recibiendo un canon mensual durante un plazo determinado; y que al terminar éste, podrá optar entre continuar el contrato en nuevas condiciones, adquirir los bienes por un precio residual, devolver los bienes o participar del precio de venta a un tercero. Además, se dan a conocer las ventajas que tiene el Arrendamiento Financiero como herramienta de financiamiento. Con referencia a los Regímenes Especiales de Admisión Temporal, se revisa la base tributaria en cuanto al Impuesto al Valor Agregado, debido a que en el Régimen de Admisión Temporal con Reexportación en el mismo Estado, se presenta un pago doble, de acuerdo a lo que dispone el Reglamento para la Aplicación de la Ley de Régimen Tributario Interno y a la Ley Orgánica de Aduanas con referencia a la depreciación, que constituye la base imponible para el cálculo del Impuesto al Valor Agregado.

Spatial Aggregation of Forest Songbird Territories and Possible Implications for Area Sensitivity

Habitat area requirements of forest songbirds vary greatly among species, but the causes of this variation are not well understood. Large area requirements could result from advantages for certain species when settling their territories near those of conspecifics. This phenomenon would result in spatial aggregations much larger than single territories. Species that aggregate their territories could show reduced population viability in highly fragmented forests, since remnant patches may remain unoccupied if they are too small to accommodate several territories. The objectives of this study were twofold: (1) to seek evidence of territory clusters of forest birds at various spatial scales, lags of 250-550 m, before and after controlling for habitat spatial patterns; and (2) to measure the relationship between spatial autocorrelation and apparent landscape sensitivity for these species. In analyses that ignored spatial variation of vegetation within remnant forest patches, nine of the 17 species studied significantly aggregated their territories within patches. After controlling for forest vegetation, the locations of eight out of 17 species remained significantly clustered. The aggregative pattern that we observed may, thus, be indicative of a widespread phenomenon in songbird populations. Furthermore, there was a tendency for species associated with higher forest cover to be more spatially aggregated [ERRATUM].

Theory and observations of ice particle evolution in cirrus using Doppler radar: evidence for aggregation

Vertically pointing Doppler radar has been used to study the evolution of ice particles as they sediment through a cirrus cloud. The measured Doppler fall speeds, together with radar-derived estimates for the altitude of cloud top, are used to estimate a characteristic fall time tc for the `average' ice particle. The change in radar reflectivity Z is studied as a function of tc, and is found to increase exponentially with fall time. We use the idea of dynamically scaling particle size distributions to show that this behaviour implies exponential growth of the average particle size, and argue that this exponential growth is a signature of ice crystal aggregation.

Spatial and temporal scale issues in determining biomass burning regimes in Bolivia and Peru

ATSR-2 active fire data from 1996 to 2000, TRMM VIRS fire counts from 1998 to 2000 and burn scars derived from SPOT VEGETATION ( the Global Burnt Area 2000 product) were mapped for Peru and Bolivia to analyse the spatial distribution of burning and its intra- and inter-annual variability. The fire season in the region mainly occurs between May and October; though some variation was found between the six broad habitat types analysed: desert, grassland, savanna, dry forest, moist forest and yungas (the forested valleys on the eastern slope of the Andes). Increased levels of burning were generally recorded in ATSR-2 and TRMM VIRS fire data in response to the 1997/1998 El Nino, but in some areas the El Nino effect was masked by the more marked influences of socio-economic change on land use and land cover. There were differences between the three global datasets: ATSR-2 under-recorded fires in ecosystems with low net primary productivities. This was because fires are set during the day in this region and, when fuel loads are low, burn out before the ATSR-2 overpass in the region which is between 02.45 h and 03.30 h. TRMM VIRS was able to detect these fires because its overpasses cover the entire diurnal range on a monthly basis. The GBA2000 product has significant errors of commission (particularly areas of shadow in the well-dissected eastern Andes) and omission (in the agricultural zone around Santa Cruz, Bolivia and in north-west Peru). Particular attention was paid to biomass burning in high-altitude grasslands, where fire is an important pastoral management technique. Fires and burn scars from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) data for a range of years between 1987 and 2000 were mapped for areas around Parque Nacional Rio Abiseo (Peru) and Parque Nacional Carrasco (Bolivia). Burn scars mapped in the grasslands of these two areas indicate far more burning had taken place than either the fires or the burn scars derived from global datasets. Mean scar sizes are smaller and have a smaller range in size between years the in the study area in Peru (6.6-7.1 ha) than Bolivia (16.9-162.5 ha). Trends in biomass burning in the two highland areas can be explained in terms of the changing socio-economic environments and impacts of conservation. The mismatch between the spatial scale of biomass burning in the high-altitude grasslands and the sensors used to derive global fire products means that an entire component of the fire regime in the region studied is omitted, despite its importance in the farming systems on the Andes.

Temporal patterns of nutrient availability around nests of leaf-cutting ants (Atta colombica) in secondary moist tropical forest

Leaf-cutting ants consume up to 10% of canopy leaves in the foraging area of their colony and therefore represent a key perturbation in the nutrient cycle of tropical forests. We used a chronosequence of nest sites on Barro, Colorado Island, Panama, to assess the influence of leaf-cutting ants (Atta colombica) on nutrient availability in a neotropical rainforest. Twelve nest sites were sampled, including active nests, recently abandoned nests (<1 year) and long-abandoned nests (>1 year). Waste material discarded by the ants down-slope from the nests contained large concentrations of nitrogen and phosphorus in both total and soluble forms, but decomposed within one year after the nests were abandoned. Despite this, soil under the waste material contained high concentrations of nitrate and ammonium that persisted after the disappearance of the waste, although soluble phosphate returned to background concentrations within one year of nest abandonment. Fine roots were more abundant in soil under waste than control soils up to one year after nest abandonment, but were not significantly different for older sites. In contrast to the waste dumps, soil above the underground nest chambers consistently contained lower nutrient concentrations than control soils, although this was not statistically significant. We conclude that the 'islands of fertility' created by leaf-cutting ants provide a nutritional benefit to nearby plants for less than one year after nest abandonment in the moist tropical environment of Barro Colorado Island. Published by Elsevier Ltd.