Resultados de investigación

Corona discharge and total discharge from the tip of a copper wire. The ground plane is placed at 15 cm from the tip. The voltage needed to break the air insulation is around 87 kV.

Corona glow in a high-voltage cable at 17 kV and in a typical connector tip at the end of the cable. This picture was taken to test if the connector would affect in the measurements of partial discharges in radio-frequency with antennas.

Surface discharges and electric-arc on a polyethylene layer. The cylindric electrode is connected to a high-voltage source. As the voltage is raised, partial discharges appear at the base of the electrode giving a faint purple glow. A further increase in the voltage creates short arcs that do not reach the ground metallic plane. Finally, for voltages above 14 kV, the arcs are able to shortcircuit the electrode to ground.

Faint corona glow around a high voltage cable at 17 kV. The electrodes below the cable are made of stainless steel and connected to ground. The electrode on the cable is only a weight to press it to ground. The glow at the left of the picture is due to a wire wrapped around the cable and also connected to ground. Photograph taken in the High-Voltage Laboratory at University Carlos III of Madrid.

Intensively managed grasslands are globally prominent ecosystems. We investigated whether experimental increases in plant diversity in intensively managed grassland communities can increase their resource use efficiency. This work consisted of a coordinated, continental-scale 33-site experiment. The core design was 30 plots, representing 15 grassland communities at two seeding densities. The 15 communities were comprised of four monocultures (two grasses and two legumes) and 11 four-species mixtures that varied in the relative abundance of the four species at sowing. There were 1028 plots in the core experiment, with another 572 plots sown for additional treatments. Sites agreed a protocol and employed the same experimental methods with certain plot management factors, such as seeding rates and number of cuts, determined by local practice. The four species used at a site depended on geographical location, but the species were chosen according to four functional traits: a fast-establishing grass, a slow-establishing persistent grass, a fast-establishing legume, and a slow-establishing persistent legume. As the objective was to maximize yield for intensive grassland production, the species chosen were all high-yielding agronomic species. The data set contains species-specific biomass measurements (yield per species and of weeds) for all harvests for up to four years at 33 sites. Samples of harvested vegetation were also analyzed for forage quality at 26 sites. Analyses showed that the yield of the mixtures exceeded that of the average monoculture in >97% of comparisons. Mixture biomass also exceeded that of the best monoculture (transgressive overyielding) at about 60% of sites. There was also a positive relationship between the diversity of the communities and aboveground biomass that was consistent across sites and persisted for three years. Weed invasion in mixtures was very much less than that in monocultures. These data should be of interest to ecologists studying relationships between diversity and ecosystem function and to agronomists interested in sustainable intensification. The large spatial scale of the sites provides opportunity for analyses across spatial (and temporal) scales. The database can also complement existing databases and meta-analyses on biodiversity–ecosystem function relationships in natural communities by focusing on those same relationships within intensively managed agricultural grasslands., Dades primàries associades a un article publicat a la revista Journal of Applied Ecology disponible a l'adreça https://doi.org/10.1111/1365-2664.12991

Conjunto de datos citado en el artículo, con el mismo título, publicado en la revista Plos One, 9(7), disponible en: http://hdl.handle.net/10532/2616

Peer Reviewed

Fotografía tomada en Palamós, en enero de 2013 -- 1er premio en el Concurso Fotográfico de SEF (Sociedad Española de Ficología), Dictyota cyanoloma es una alga parda (Phaeophyceae) del Mediterráneo recientemente descrita por Tronholm et al. (2010) cuya distribución actual incluye la Península Ibérica, la región macaronésica, el Adriático y Turquía. Se trata de una especie que vive generalmente en zonas portuarias o en sus alrededores y que según parece se encuentra en expansión. Todo hace pensar que es una especie de reciente introducción en el Mediterráneo. Con el fin de verificar esta hipótesis y conocer el posible origen de la especie, así como su fenología, se está llevando a cabo un proyecto subvencionado por la Fundación Biodiversidad. Por un lado, se estudia la distribución actual de la especie en las costas mediterráneas de la península ibérica. Por otro, se analiza la variabilidad genética de D. cyanoloma y se compara con otras dos especies mediterráneas del género (D. fasciola y D. mediterranea)., Peer reviewed

Contiene la imagen utilizada en el workshop en español e inglés.-- Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, Con motivo de la semana internacional del acceso abierto 2014, DIGITAL.CSIC organizó el seminario "Nuevos sistemas para la evaluación científica, peer-review y acceso abierto" para debatir desde distintas perspectivas cómo afectan las actuales transformaciones en la comunicación científica y políticas de acceso abierto a los modelos de evaluación y análisis del impacto., Peer reviewed

La colección violeta de micrografías recoge los datos micrográficos obtenidos mediante microscopía electrónica de barrido (MEB) sobre estructuras metálicas de objetos fabricados en oro procedentes de la Península ibérica, que pueden ser fechados entre los inicios de la metalurgia y el fin de la Antigüedad., Peer reviewed