Air-driven reverse buoyancy

Abstract Air-induced fluidization in vibrated granular beds can be responsible of the phenomenon of reverse buoyancy. We show that the air flow induced across the bed, as the gap in the bottom of the cell evolves, can fluidize the bed in a similar way as in gas-fluidized static beds and consequently a buoyancy force can arise. To quantify this mechanism we use Kroll's model.

Análisis de la firma electrónica en el contexto de la Transformación Digital en la Unión Europea

[ES] El futuro profesional de la informática recibe una escasa formación en lo que respecta a su vinculación con el marco legal, político y económico del sector europeo. A pesar de que las implicaciones laborales son muchas, las más de las veces el parco acercamiento suele quedarse en un estado teórico y escaso. Con la presente experiencia se busca acercar al alumnado al contexto europeo legal técnico y económico que rodea a la firma electrónica. Este elemento está vinculado con la autentificación e identificación electrónica de ciudadanos europeos en los servicios ofrecidos por el sector público y privado dentro del Mercado Único Digital. Esta estrategia es promovida por la Unión Europea como un paso más dentro de la teoría de la integración de mercados. La involucración de los autores en este contexto es debido a su participación en el proyecto financiado por la Comisión Europea denominado ‘Crossborder authentication in European cloud platforms according to the eIDAS Regulation (EUROLogin), de cuyos resultados se deriva información de interés para el seguimiento e investigación por parte del alumnado.Los autores de la presente comunicación quieren agradecer expresamente a la Comisión Europea y a la Agencia Ejecutiva de Innovación y Redes (Innovation and Networks Executive Agency), así como, al programa marco de financiación Connecting Europe Facility (CEF Telecom) por la financiación otorgada dentro de este marco al proyecto „Cross-border authentication in European cloud platforms according to the eIDAS Regulation (EUROLogin) con el número de Acción 2018-EU-IA-0026 y número de Grant Agreement INEA/CEF/ICT/A2018/1633379.Oltra Gutiérrez, JV.; Montesa Andrés, JO.; Stratu Strelet, D.; Gil Gómez, H.; Oltra Badenes, RF.; oltra gutie (2020). Análisis de la firma electrónica en el contexto de la Transformación Digital en la Unión Europea. Editorial Universitat Politècnica de València. 919-926. https://doi.org/10.4995/INN2019.2019.10942OCS91992

Genetic patterns and conservation of the Scarlet Macaw (Ara macao) in Costa Rica

Once widely distributed throughout the lowland forests of Costa Rica, scarlet macaws (Ara macao) have been reduced to two major, geographically separated, pop ulations along the Pacific slope. Past demographic declines raise conservation concerns regarding the detrimental effects of population fragmentation. This investigation aimed to evaluate the current status of scarlet macaws along the Pacific slope by examining levels of genetic variation and patterns of genetic structure within and among remnant populations. Statistical analyses using multilocus genotypes revealed strong differentiation between Central and South Pacific populations, suggesting local geographic barriers have historically restricted gene flow between these locali ties. High genetic diversity suggests neither population suffers from genetic erosion, likely resulting from relatively large population sizes and high dispersal capacity and longevity. However, evidence of disequilibrium within the Central Pacific population infers anthropogenic threats have disrupted natural population dynamics. These results advo cate on focusing available resources on habitat restorationUniversidad Nacional, Costa Rica.Instituto Internacional en Conservación y Manejo de Vida Silvestr

Dendrochronological study of the Canal del Roc Roig avalanche path: first results of the Aludex project in the Pyrenees

ABSTRACT. Historical data about ancient avalanches are scarce in the Pyrenees. Dendrochronology can provide new data about past avalanches and their return period, but up to now little research has been carried out with this purpose. The Aludex project aims to obtain information about the frequency and extent of extreme avalanches, using a dendrochronological and a nivo-meteorological approach. In this paper, we present the results of a dendrochronological study of the Canal del Roc Roig avalanche path which was affected by two extreme avalanches in February 1996. This first dendrochronological study has permitted us to assess the tree-ring signals due to avalanche events in 53 out of 132 dated trees. The trees presented a variety of responses to the 1996 avalanche events. It is shown that the type of tree-ring signal depends on tree age. The methodology has proved successful in detecting the 1996 and 1972 documented avalanche events, and provided outstanding evidence of undocumented past events such as one in 1930