Diseño y evaluación de una secuencia de enseñanza para introducir los conceptos de sustancia y reacción química en la educación secundaria

Este trabajo propone una secuencia de enseñanza que facilite el aprendizaje de los conceptos de sustancia, sustancia simple, compuesto y reacción química. La secuenciación y organización de los contenidos se fundamenta en un análisis histórico de la construcción de la teoría atómica daltoniana y la secuencia de enseñanza se completa mediante dos programas de actividades basados en el modelo de aprendizaje como investigación orientada. La eficacia de la secuencia de enseñanza se evaluó mediante un diseño postest en el que se comparaban las respuestas de los alumnos de los grupos experimentales (N=187) con las formuladas por estudiantes de grupos de control que no habían sido tratados (N= 381). Los resultados muestran que la utilización del programa ha favorecido un mayor aprendizaje en los estudiantes de los grupos experimentales

Designing New Models for Energy Efficiency in Urban Freight Transport for Smart Cities and its Application to the Spanish Case

AbstractConsidering that the transport sector is responsible for 30% of the CO2 emissions in the EU, reaching up to 40% in urban areas, the efforts for technological improvements and innovation in transportation have been increasing during the last few decades. It is evident that urban freight distribution requires innovative solutions that are capable of improving the efficiency of transport whilst promoting innovative use of renewable energy, thus reducing energy consumption and associated GHG emissions while adopting and not stifling economic development. In this context, six Mediterranean cities (Barcelona, Bologna, Piraeus, Rijeka and Valencia)) collaborated with the purpose of contributing to the improvement of energy efficiency on urban freight transport as part of the SMILE Project (2015) (SMart green Innovative urban Logistics Models for Energy efficient mediterranean cities project), funded by the MED Programme. The SMILE project aims to improve the energy efficiency of Mediterranean cities through the promotion of innovative ‘green’ and cost effective solutions for urban freight logistics, addressing the target of green and smart urban development. This paper shows the results of the live test of smart city urban logistics solutions in the cities of Barcelona and Valencia that consisted of combining the use of electric tricycles and Transhipment terminals (or Urban Consolidation Centres) for the last-mile delivery of parcels and small shipments. A thoughtful analysis of the quantitative outcomes of the pilot test in both cities are presented from different perspectives: economical, operational, energy efficiency, environmental and social

Preface. Palaeodiversity and Palaeoecology of Iberian Ecosystems. New insights into the Phanaerozoic biotas from Spain and Portugal

Preface. Palaeodiversity and Palaeoecology of Iberian Ecosystems. New insights into the Phanaerozoic biotas from Spain and Portuga

Biochronological data for the Early Pleistocene site of Quibas (SE Spain) inferred from rodents assemblage

In this paper, the rodent fauna from the Early Pleistocene of Gruta1 (Quibas karstic complex, Murcia, SE Spain) is described. The assemblage includes one arvicoline (Allophaiomys sp.), two murines (Apodemus ex gr. mystacinus-epimelas, Castillomys rivas) and one glirid (Eliomys quercinus). The rodent assemblage indicates an age very close to the age of Fuente Nueva 3 and Barranco León 5 in the Guadix-Baza Basin, and Sima del Elefante in the Atapuerca karstic complex, between ca. 1.2-1.4My.

Selection for Robustness in Mutagenized RNA Viruses

Mutational robustness is defined as the constancy of a phenotype in the face of deleterious mutations. Whether robustness can be directly favored by natural selection remains controversial. Theory and in silico experiments predict that, at high mutation rates, slow-replicating genotypes can potentially outcompete faster counterparts if they benefit from a higher robustness. Here, we experimentally validate this hypothesis, dubbed the “survival of the flattest,” using two populations of the vesicular stomatitis RNA virus. Characterization of fitness distributions and genetic variability indicated that one population showed a higher replication rate, whereas the other was more robust to mutation. The faster replicator outgrew its robust counterpart in standard competition assays, but the outcome was reversed in the presence of chemical mutagens. These results show that selection can directly favor mutational robustness and reveal a novel viral resistance mechanism against treatment by lethal mutagenesis

The range and extent of the Vallesian Crisis (Late Miocene): new prospects based on the micromammal record from the Vallès-Penedès basin (Catalonia, Spain)

The Vallesian Crisis was initially recognized as a local event, which implied the extinction of certain rodent and artiodactyl genera coincidingwith the early/late Vallesian boundary (at 9.7 Ma). Following works increased the range and extent of this event to encompass allEurope and involve a great number of mammal taxa. Here, we analyze the Vallesian rodent and insectivore record of the Vallès-Penedèsbasin (Catalonia, Spain), where the crisis was first recognized. We show that the quality of the record before the crisis is comparativelymuch better than afterwards so diversity appears inflated and extinction rates are overrated. Accordingly, we used inferred taxon rangesand rarefaction to calculate new diversity measures independent of sample size. These measures virtually eliminate the Vallesian Crisis,showing that diversity somewhat decreased during the earliest late Vallesian and soon recovered afterwards. This is because it cannot bediscarded that several rare taxa, customarily said to have disappeared during the crisis, are in fact present. Amongst the rodents and insectivores,these taxa include genera that are generally rare and show a discontinuous record during the early Vallesian. These are presumedspecialists adapted to humid forested environments such as flying squirrels, beavers or certain dormice, most of them being only recordedwhen the sample size is large enough. Alternatively, these genera may have been associated to very specific habitats which, for an unknownreason, are not sampled during the late Vallesian. Our results cast serious doubts on the very existence of the Vallesian Crisis suggesting thatrather than an abrupt event a series of extinctions occurred during a longer time span. It has not been evaluated whether the same patternis observed in the case of large mammals and in other areas. However, our results show that biases introduced by the quality of the recordneed to be taken into account when assessing the extent of the event.La Crisis Vallesiense fue inicialmente definida como un fenómeno local que implicó la desaparición de ciertos géneros de roedores y artio­dáctilos coincidiendo con el límite entre Vallesiense inferior y superior (hace 9.7 Ma). Trabajos posteriores ampliaron el ámbito y alcance de este evento hasta incluir toda Europa e implicar un gran número de taxones de mamíferos. En este trabajo analizamos el registro Vallesiense de roedores e insectívoros de la cuenca del Vallès-Penedès (Cataluña, España), donde la crisis fue reconocida por primera vez. Se muestra que la calidad del registro fósil con anterioridad a la crisis es comparativamente mucho mejor que la de después de modo que se magnifica la diversidad y se exageran las tasas de extinción. Por lo tanto, se ha utilizado rarefacción y se han inferido rangos estratigráficos a fin de calcular nuevas medidas de diversidad independientes del tamaño de la muestra. Estas medidas eliminan virtualmente la Crisis Vallesiense, mostrando que la diversidad disminuyó a principios del Vallesiense superior para recuperarse poco después a finales de esta edad. Esto es debido a que no podemos descartar que diversos taxones poco abundantes, normalmente citados como víctimas de la crisis, estuvieran de hecho presentes. Entre los roedores e insectívoros dichos taxones incluyen géneros que son generalmente raros y que muestran un registro discontinuo durante el Vallesiense inferior. Se trata de supuestos especialistas adaptados a ambientes boscosos húmedos tales como ardillas voladoras, castores o ciertos lirones, la mayoría de los cuales sólo se encuentran cuando el tamaño de la muestra es lo suficientemente grande. Alternativamente, estos géneros podrían haber estado asociados a hábitats muy específicos que por algún motivo no están siendo muestrea­dos durante el Vallesiense superior. Nuestros resultados cuestionan seriamente la existencia de la Crisis Vallesiense y sugieren que en lugar de un evento abrupto podría tratarse de una serie de extinciones que habrían sucedido durante un período más largo. Queda pendiente de evaluación si el mismo patrón se observa en el caso de los grandes mamíferos y en otras áreas. No obstante nuestros resultados muestran que se deberían tomar en consideración las desviaciones introducidas por la calidad del registro al analizar el alcance de este evento

Micromammalian faunas from the middle miocene (middle Aragonian) of the Tudela formation (Ebro Basin, Spain)

Two new fossil micromammal localities of Middle Miocene age (Pico del Fraile 2, PF2 and Sancho Abarca 5, SA5) from the Tudela Formation (northeastern Ebro Basin) are described. PF2 contains rodents and insectivores of Aragonian age (local zone Dc). The rodent assemblage from the locality SA5 is very scarce and probably of Middle Aragonian age, like PF2. The micromammal fauna from the locality PF2 is very similar to that from Valdemoros 3B (VA3B) (Calatayud-Daroca Basin), including Microdyromys cf. remmerti, a species until now only described from the Miocene of the Daroca-Villafeliche area. Among the fauna recorded in PF2, a form of Democricetodon is described. The sedimentary record of the Pico del Fraile and Sancho Abarca sections and the mammalian findings extend the stratigraphic and paleontological knowledge of this part of the Ebro Basin, and allow its study in a continuous stratigraphic context

Análisis de Tensiones Residuales Inducidas en Aleaciones Metálicas por Tratamientos Superficiales mediante Ondas de Choque Generadas por Láser

En el presente artículo se plantea un estudio sobre la medida de tensiones residuales mediante el método del taladro en banda extensométrica (o agujero ciego) aplicado en probetas de aluminio 2024-T351, previamente tratadas superficialmente mediante laser shock processing (método de tratamiento superficial por ondas de choque generadas por láser, conocido como LSP). Finalmente, se realiza una comparación entre los resultados experimentales obtenidos al medir las tensiones residuales obtenidas en probetas tratadas mediante LSP y los valores obtenidos mediante un modelo de simulación