First sighting of Zebrasoma flavescens (Teleostei: Acanthuridae) and Balistoides conspicillum (Teleostei: Balistidae) in the Mediterranean Sea: Two likely aquarium releases

Here we provide the first documented occurrence of the yellow tang Zebrasoma flavescens and of the clown triggerfish Balistoides conspicillum in the Mediterranean Sea. These tropical fishes were photographed in October 2008 off Sitges (Costa Daurada, Spain: 41°13'27.09" N; 1°47'22.35" E) and in July 2012 in front of Palamós (Costa Brava, Spain: 41°50'56.19" N; 3°8'26.29" E), respectively. Their possible release from private aquaria is discussed

Alumnos con deficiencia psíquica: aspectos a tener en cuenta en las clases de educación física

Los alumnos con deficiencia psíquica tienen los mismos estadios de desarrollo que el resto de niños, pero tienen un retraso en su desarrollo. A esto se añaden una serie de características afectivas, sociales, etc., que hay que tener en cuenta para planificar la clase. El artículo propone una seria de aspectos metodológicos que nos van a permitir dar las clases en óptimas condiciones

Homoclinic snaking in bounded domains

Homoclinic snaking is a term used to describe the back and forth oscillation of a branch of time-independent spatially localized states in a bistable, spatially reversible system as the localized structure grows in length by repeatedly adding rolls on either side. On the real line this process continues forever. In finite domains snaking terminates once the domain is filled but the details of how this occurs depend critically on the choice of boundary conditions. With periodic boundary conditions the snaking branches terminate on a branch of spatially periodic states. However, with non-Neumann boundary conditions they turn continuously into a large amplitude filling state that replaces the periodic state. This behavior, shown here in detail for the Swift-Hohenberg equation, explains the phenomenon of “snaking without bistability”, recently observed in simulations of binary fluid convection by Mercader, Batiste, Alonso and Knobloch (preprint)

Microscopic spheroidal particles obtained by laser cutting

In this work we study the characteristics of the particles ejected from the cutting zone of a SAE 1010 steel while using a CO2 gaseous laser with the purpose of determining the feasibility to use this technique in the production of microscopic particles for nuclear applications [2] as well as for other scientific and technological uses [1].Instituto de Física La Plat

A blue sky catastrophe in double-diffusive convection

A global bifurcation of the blue sky catastrophe type has been found in a small Prandtl number binary mixture contained in a laterally heated cavity. The system has been studied numerically applying the tools of bifurcation theory. The catastrophe corresponds to the destruction of an orbit which, for a large range of Rayleigh numbers, is the only stable solution. This orbit is born in a global saddle-loop bifurcation and becomes chaotic in a period doubling cascade just before its disappearance at the blue sky catastrophe.Comment: 4 pages, 6 figures, REVTeX, To be published in Physical Review Letter

Toldo urbano: Posibilidades de reducción de la demanda de refrigeración

As a result of the current economic and energy crisis, it has become necessary to rethink urban planning, starting from a global concept of efficiency and considering buildings not as isolated entities, but as part of an urban system, which consumes energy on a much larger scale. The connection between urban morphology and microclimate is a widely discussed question, including issues like the urban heat island phenomenon or outdoor comfort in open spaces. However, there is still a lot of work to be done regarding the influence of these microclimatic variations on building energy consumption. In that sense, would it be possible to apply efficient measures of microclimate modification on an urban scale to increase comfort levels in public spaces while at the same time, reducing building consumption? This paper focuses on urban canopy shading. Its effectiveness as a shading device and its capability to improve outdoor climate in areas with an excess of solar radiation is widely demonstrated. In this case, its effect on indoor climate of is evaluated. The case study is located in Cordoba (Spain), as an example of a climate with a hot and dry summer (according to CTE, level 4). A complete street canyon model has been created. Two buildings, one on each side of the street canyon, have been tested using an energy simulation software (Design Builder). Model features and simulation settings correspond to real values. Urban canopy shading effectiveness has been analyzed according to cooling demand decrease, taking into account both buildings. Spatial factors (street orientation, width-height ratio, windows-opaque ratio) and material factors (U-values and skin mass, % obstruction) have been considered. Results show 18% to 45% cooling demand decrease due to the canopy shading. Spatial factors are much more relevant than material factors: windows-opaque ratio is a determining factor, in contrast to mass and U-values. This study shows the importance of evaluating both urban facades, which means working from an urban perspective beyond the local scale of a single building.El contexto de crisis económica y energética en que nos encontramos, hace necesario repensar la forma de planificar la ciudad partiendo de un concepto global de eficiencia y entendiendo los edificios no como entes aislados que consumen energía, sino como parte de un sistema, consumidor una escala mucho mayor. La relación entre morfología urbana y el microclima es una cuestión ampliamente tratada, abordándose el fenómeno isla de calor o el confort en espacios urbanos. Sin embargo, en cuanto a la influencia de estas variaciones microclimáticas sobre el consumo energético del edificio, aún queda mucho por hacer. En esta línea, nos planteamos: ¿sería posible implantar estrategias de modificación del microclima a escala urbana, que aumenten los niveles de confort en exterior y, simultáneamente disminuyan el consumo de los edificios? En este artículo se analiza el caso del toldo urbano. Su eficacia como elemento de sombra, y su capacidad de mejorar las condiciones exteriores en climas con exceso de radiación solar, está ampliamente demostrada. En esta ocasión, nos centramos en su repercusión sobre el ambiente interior en edificios residenciales. El caso de estudio se localiza en Córdoba (España), ejemplo de clima con verano cálido y seco (según CTE, severidad 4). Se ha creado un modelo de cañón urbano, en cuya parte central se ubican los dos edificios (uno a cada lado de la calle) objeto de simulación energética con Design Builder. Las características del modelo y simulación, responden a condiciones similares a las edificaciones residenciales del entorno. La efectividad del toldo se ha analizado en base a la disminución de demanda de refrigeración que genera, teniendo en cuenta ambos edificios. Se han considerado tanto variables espaciales (orientación de la calle, proporción ancho-alto, % de hueco en fachadas) como materiales (Transmitancia y masa de los cerramientos,% obstrucción solar del toldo). Los resultados reflejan reducciones de demanda entre el 18 y el 45% y una mayor importancia de las variables espaciales frente a las materiales. El % de hueco en fachada se muestra como parámetro de gran relevancia, en contraposición a la masa y la transmitancia. Se concluye que el análisis debe efectuarse considerando las dos fachadas urbanas en su totalidad, es decir, partiendo de una perspectiva urbana que trasciende de la escala local de edificio

Morphology and Phase Composition of Particles Produced by Electro-Discharge-Machining of Iron

Towards producing metallic particles of controlled size and spherical shape, which are of technological importance, we have collected in the filters of an electro-discharge-machine (EDM) the material ejected from the surface of EDM iron pieces. The conditions of machining were varied for kerosene and water as dielectrics, using a discharge current of 25 A and duration times of 16 and 3072 μs for kerosene and of 32, 384 and 768 μs for water, respectively. Scanning electron microscopy was used to assess the effect of the time of discharge on the size of the particles. Mossbauer spectroscopy and X-ray diffraction revealed that for kerosene EDM particles only cementite-like carbides of diverse stoichiometry were formed. While no oxide was found for kerosene spheres, the analyses showed that besides the main fraction of α-Fe, a small percentage of wustite (and traces of hematite for the 384 μs sample) formed on the water EDM ones.Facultad de Ciencias ExactasInstituto de Física La Plat

Construcción sostenible y materiales en Andalucía

In this paper, we describe the evolution of materials used in construction in Andalusia in the period 2007-2015 through analysis of the official databases, to assess sustainability. We study the envelope and exterior frames in residential and non-residential buildings and new buildings in general. We analyze housing according to their flooring and interior frame. We also analyze new buildings according to their envelope. Wood is increasingly present in construction next to other materials such as stone and plastics. There is a tendency toward sustainability in Andalusia in terms of increased percentages of more sustainable material, especially in nonresidential buildings. Non-residential buildings have a greater presence of stone and less of continuous coating in external walls, and exterior carpentry shows a greater presence of wood (11% compared to 6%) and much less of aluminum (55% compared to 89%). The graphics indicate a turning point in 2014 that makes us wonder if this is a change of cycle. The crisis in the construction sector has led to a greater sustainability that seems to be starting to get lost in the beginning of the recovery as it is evidenced in the promotion and increase of differences in 2014 and 2015El presente trabajo El presente trabajo muestra la evolución de los materiales utilizados en la construcción en Andalucía en el período 2007-2015, analizando las bases de datos oficiales, para valorar la sostenibilidad. Estudiamos los cerramientos y carpintería exterior en edificios de uso residencial y no residencial y en edificios de nueva planta en general. Analizamos las viviendas según su acabado interior, en suelos y carpintería interior y también el cerramiento exterior de viviendas en edificios de nueva planta. La madera está cada vez más presente en la construcción junto a otros materiales como pétreos y plásticos. Hay una tendencia hacia la sostenibilidad en Andalucía en cuanto a aumento de porcentajes de materiales más sostenibles, más presente en edificios de uso no residencial. Los edificios no residenciales tienen mayor presencia de pétreos y menor de revestimiento continuo en cerramientos exteriores, y en carpintería exterior mayor presencia de madera (11% respecto a 6%) y mucho menor de aluminio (55% respecto a 89%). Las gráficas indican un punto de inflexión en 2014 que nos lleva a preguntarnos si es un cambio de ciclo. La crisis de la construcción ha conllevado una mayor sostenibilidad que parece empezar a perderse en el comienzo de la recuperación como se comprueba en el ascenso y aumento de diferencias en 2014 y 2015