979 research outputs found

    Strength demands of tall wind turbines subject to earthquakes and wind load

    Get PDF
    Wind and earthquake load have historically been conceived to act independently. However, if we reflect on the fact that major seismic events are usually followed by a number of aftershocks and that wind is constantly flowing at high intensities around wind farms, which induces additional demands of resistance to infrastructure, then the joint probability of middle-to strong earthquakes and low-to mild wind events becomes more relevant. In this paper a generalised approach is used to estimate the ratio between earthquake and wind forces and their effect on infrastructure. Following, a probabilistic analysis is carried out to show that under certain conditions the combination of these natural events can induce additional demands of strength and ductility to wind turbines which could lead to unforeseen damage

    Tasas de deposición de polvo atmosférico en un área semiárida del entorno mediterráneo occidental

    Get PDF
    We evaluated the deposition rate of atmospheric dust in a non urban area of the Granada Depression (SE of Iberian Peninsula). By using in part existing methodology, we determined a rate of 23.06 g·m2·yr-1 on the basis of weekly observations, that showed marked variations, partially controlled by Saharan winds. The components of the dust can indicate source area. Thus, southerly winds provide considerable allochthonous components from North Africa, while others are local. Despite the scarcity of industrial activity, signs of contamination were recorded. The employed methodology complements the work methods used by other researchers. The role of airborne sediments provides an illustration in soil genesis of the Mediterranean region.La Depresión de Granada (SE de la Península Ibérica) presenta, en áreas no urbanas y no industriales, una tasa anual de deposición de polvo atmosférico de 23,06 g·m2·año-1 , obtenida a partir de observaciones semanales durante el año 1992. Este dato es el resultado de una metodología propia, que complementa los métodos de trabajo seguidos por otros investigadores. Dada la ubicación de la estación, este valor es representativo del fondo regional de partículas sólidas en suspensión. La distribución temporal de las tasas presenta importantes fluctuaciones, relacionadas con la dirección predominante del viento, que también parece tener influencia sobre los componentes del polvo. Estos datos se integran en el conocimiento de los procesos edafogenéticos de los suelos mediterráneos

    Influence of temperament on performance and carcass quality of commercial Brahman steers in a Colombian tropical grazing system

    Get PDF
    Temperament is defined as individual behavioral responses to potentially fear-eliciting or challenging situations related to human presence and handling. A total of 190 steers of commercial Zebu Brahman (Bos indicus) were used in this study, selected when they were between 10 and 11 months of age, fattened for 24 months (720 days) and slaughtered between 34 and 35 months of age. Using a temperament index (based on two tests: chute and exit score), animals were classified as calm, restless, or nervous. In general, calm animals had a longer carcass, a higher slaughter and fasting weight, and a normal pH24 (<5.7). However, carcass yield was significantly higher in nervous than in restless animals, but did not differ from that of calm steers. It is important to note that these results were obtained under experimental conditions, therefore, effects could have a greater impact on carcass quality under commercial conditions. © 2022 The Author

    Environment-driven reactivity of H2 on PdRu surface alloys

    Get PDF
    The dissociative adsorption of molecular hydrogen on PdxRu1−x/Ru(0001) (0 ≤ x ≤ 1) has been investigated by means of He atom scattering, Density Functional Theory and quasi-classical trajectory calculations. Regardless of their surroundings, Pd atoms in the alloy are always less reactive than Ru ones. However, the reactivity of Ru atoms is enhanced by the presence of nearest neighbor Pd atoms. This environment-dependent reactivity of the Ru atoms in the alloy provides a sound explanation for the striking step-like dependence of the initial reactive sticking probability as a function of the Pd concentration observed in experiments. Moreover, we show that these environment-dependent effects on the reactivity of H2 on single atoms allow one to get around the usual constraint imposed by the Brønsted–Evans–Polanyi relationship between the reaction barrier and chemisorption energy.Fil: Ramos Acevedo, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; ArgentinaFil: Minniti, M.. Universidad Autónoma de Madrid; EspañaFil: Díaz, C.. Universidad Autónoma de Madrid; EspañaFil: Farias, D.. Universidad Autónoma de Madrid; EspañaFil: Miranda, R.. Universidad Autónoma de Madrid; España. Instituto Madrileño de Estudios Avanzados en Nanociencia; EspañaFil: Martín, F.. Universidad Autónoma de Madrid; España. Instituto Madrileño de Estudios Avanzados en Nanociencia; EspañaFil: Martinez, Alejandra Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; ArgentinaFil: Busnengo, Heriberto Fabio. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentin

    “Alfabetización informacional de docentes/investigadores de universidades privadas de la provincia de Mendoza”

    Get PDF
    El Proyecto plantea la urgencia de una nueva alfabetización sistematizada que responda a lasnecesidades concretas de los actores que se ha destinado. Debe ser una alfabetización múltipleque capacite a los mismos en los nuevos lenguajes, las nuevas herramientas informacionales y eldesarrollo crítico en la búsqueda de la información.Las habilidades de información tienen un carácter metodológico y transversal. En tanto podemosconsiderarlas necesarias para el dominio de cualquier materia. Por ello la AlfabetizaciónInformacional debería ser resultado del empleo de métodos didácticos que implicaran suconocimiento y uso en el seno de todas las asignaturas.Esto llevaría al aprendizaje “en contexto” de las habilidades de información, lo cuales es altamentepositivo y coherente. Es positivo porque la motivación para las tareas de aprendizaje es más fácilcuando el acceso y uso de la información se lleva acabo no en abstracto o en general, sino con unobjetivo y una temática. Y es coherente porque en todas las disciplinas y asignaturas concretashay dificultades para conocer los recursos, las características propias de la documentación, hábitospropios de comunicación y publicación.Con este proyecto se ha comprobado que los docentes/investigadores universitarios tienen escasapráctica en la enseñanza de habilidades de información. El 80% de los mismos -encuestados- noconsultan las bases de datos, ni bibliotecas digitales

    Ubiquinone, Ezetimibe/Simvastatin and Rosuvastatin Effects on Mitochondrial Function in Diabetic Polyneuropathy

    Get PDF
    Diabetic polyneuropathy (DPN) pathophysiologic findings include loss of multifocal and focal nerve fibers secondary to axonal degeneration and segmental demyelization due to oxidative stress and mitochondrial dysfunction induced by chronic hyperglycaemia

    Very Low-Calorie Diets in Type 2 Diabetes Mellitus: Effects on Inflammation, Clinical and Metabolic Parameters

    Get PDF
    Type 2 diabetes mellitus (DM) is a chronic and multifactorial disease strongly linked to a low-grade inflammatory process. Thus far, type 2 DM is generally regarded as an incurable disease by common therapies. However, very low-calorie diet (VLCD) regimens have demonstrated beneficial and rapid effects on glucose metabolism in subjects with type 2 DM. These beneficial effects include improvement of diabetes complications, insulin sensitivity and reduction in glycaemia, glycated hemoglobin (HbA1C), and triglyceride levels. VLCD regimens commonly comprise no more than 800 kcal/day and are therefore associated with rapid weight loss in overweight and obese individuals. This group of diets positively affects local/systemic inflammation and oxidative stress (OS) by modulating inflammatory cytokines, adipokines and endogenous antioxidant levels. The investigation of VLCDs in the field of type 2 DM treatment is progressively augmenting due to the multiple benefits in cardiometabolic health of overweight/obese subjects with type 2 DM. Here, we gather and review the evidence regarding the role of inflammation and OS in individuals with type 2 DM under VLCD regimens

    Graphene catalyzes the reversible formation of a C–C bond between two molecules

    Get PDF
    Carbon deposits are well-known inhibitors of transition metal catalysts. In contrast to this undesirable behavior, here we show that epitaxial graphene grown on Ru(0001) promotes the reversible formation of a C–C bond between −CH2CN and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). The catalytic role of graphene is multifaceted: First, it allows for an efficient charge transfer between the surface and the reactants, thus favoring changes in carbon hybridization; second, it holds the reactants in place and makes them reactive. The reaction is fully reversible by injecting electrons with an STM tip on the empty molecular orbitals of the product. The making and breaking of the C–C bond is accompanied by the switching off and on of a Kondo resonance, so that the system can be viewed as a reversible magnetic switch controlled by a chemical reactionJ.J.N., F.C., R.M., and A.L.V.d.P. acknowledge the Ministerio de Economía y Competitividad (MINECO) project FIS2015-67367-C2-1-P and Comunidad de Madrid projects MAD2D P2013/MIT-3007 and Nanofrontmag S2013/MIT-2850. M.P., C.D., and F.M. acknowledge the MINECO project FIS2016-77889-R and computer time from the CCC-UAM and the Red Española de Supercomputación. C.D. acknowledges a Ramón y Cajal contract from MINECO (Spain). E.M.P., J.V., and B.N.-O. acknowledge the European Research Council project MINT, ERC-StG-2012-307609. IMDEA Nanoscience acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, grant SEV-2016-0686). IFIMAC acknowledges support from the “María de Maeztu” Programme for Units of Excellence in R&D (MDM-2014-0377

    Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)

    Get PDF
    The macrozoobenthos of Mejillones Bay (23°S; Humboldt Current) was quantitatively investigated over a 7-year period from austral summer 1995/1996 to winter 2002. About 78 van Veen grab samples taken at six stations (5, 10, 20 m depth) provided the basis for the analysis of the distribution of 60 species and 28 families of benthic invertebrates, as well as of their abundance and biomass. Mean abundance (2,119 individuals m-2) was in the same order compared to a previous investigation; mean biomass (966 g formalin wet mass m-2), however, exceeded prior estimations mainly due to the dominance of the bivalve Aulacomya ater. About 43% of the taxa inhabited the complete depth range. Mean taxonomic Shannon diversity (H', Log e) was 1.54 ± 0.58 with a maximum at 20 m (1.95 ± 0.33); evenness increased with depth. The fauna was numerically dominated by carnivorous gastropods, polychaetes and crustaceans (48%). About 15% of the species were suspensivorous, 13% sedimentivorous, 11% detritivorous, 7% omnivorous and 6% herbivorous. Cluster analyses showed a significant difference between the shallow and the deeper stations. Gammarid amphipods and the polychaete family Nephtyidae characterized the 5-mzone, the molluscs Aulacomya ater, Mitrella unifasciata and gammarids the intermediate zone, while the gastropod Nassarius gayi and the polychaete family Nereidae were most prominent at the deeper stations. The communities of the three depth zones did not appear to be limited by hypoxia during non-El Niño conditions. Therefore, no typical change in community structure occurred during El Niño 1997–1998, in contrast to what was observed for deeper faunal assemblages and hypoxic bays elsewhere in the coastal Humboldt Current system
    corecore