Crystallization of para-Hydrogen: a quantum phase transition at finite temperature?

4 págs.; 3 figs.; Open Access funded by Creative Commons Atribution Licence 3.0; 7th Meeting of the Spanish Neutron Scattering Association (SETN)Recent neutron scattering measurements have revealed that para-Hydrogen prepared in its fundamental state solidifies in a crystal that do not show temperature response (temperature independent molecular displacement and first rotational level linewidth as well as negligible thermal expansion). Here, it is argued that such unique behaviour in the crystal phase can be understood if the crystallization is driven by pure quantum fluctuations.Work supported in part by grants MAT2007-65711-C04-01 and MAT2012-33633 from the Spanish Ministerio de Economía y Competitividad.Peer Reviewe

Hydrogen as energy storage for wind energy

Nowadays, problems associated with greenhouse gases emission and fuel ending, makes that renewable energy sources and hydrogen technology have high interest for governments and researchers, and become an option for an environmentaly sustainable world. Renewable energy sources, like solar energy and wind energy, have been used for the last three decades to produce electricity. Researchers and companies have improved the efficiency of this kind of systems, but they have a problem due to energy source temporality that does a fluctuation in systems power output. This fluctuation makes sometimes energy demand is higher than energy produced by the system and vice versa. Hydrogen Technology, actuating as energy storage, may solve this problem. In this paper, a wind-hydrogen installation will be described. Also, its behavior in relation to different electric demand will be analysed

Dynamic properties of liquid Ni revisited

Liquid Ni has previously been studied by different approaches such as molecular dynamics simulations and experimental techniques including inelastic neutron and X-ray scattering. Although some puzzling results, such as the shape of the sound dispersion curve for q ≤ 1.0 Å−1, have already been sorted out, there still persist some discrepancies, among different studies, for greater q-values. We have performed ab initio simulation calculations which show how those differences can be reconciled. Moreover, we have found that the transverse current spectral functions have some features which, so far, had previously been shown by high pressure liquid metals

Efecto de los grados día de ayuno y del hacinamiento previos al sacrificio sobre el contenido estomacal y respuesta de estrés en trucha arcoíris (Oncorhynchus mykiss)

El ayuno pre-sacrificio es una práctica rutinaria en acuicultura que se lleva a cabo para vaciar el aparato digestivo disminuyendo la cantidad de heces y previniendo una contaminación de la canal (Robb, 2008). Sin embargo, el ayuno puede también incrementar los niveles de estrés de los peces y si estos son lo suficientemente altos afectan a la calidad de la canal (Poli et al., 2005)

Plasma cytokines as potential biomarkers of kidney damage in patients with systemic lupus erythematosus

Background: Systemic lupus erythematosus is a heterogeneous chronic inflammatory autoimmune disorder characterized by an exacerbated expression of cytokines and chemokines in different tissues and organs. Renal involvement is a significant contributor to the morbidity and mortality of systemic lupus erythematosus, and its diagnosis is based on renal biopsy, an invasive procedure with a high risk of complications. Therefore, the development of alternative, non-invasive diagnostic tests for kidney disease in patients with systemic lupus erythematosus is a priority. Aim: To evaluate the plasma levels of a panel of cytokines and chemokines using multiplex xMAP technology in a cohort of Colombian patients with active and inactive systemic lupus erythematosus, and to evaluate their potential as biomarkers of renal involvement. Results: Plasma from 40 systemic lupus erythematosus non-nephritis patients and 80 lupus nephritis patients with different levels of renal involvement were analyzed for 39 cytokines using Luminex xMAP technology. Lupus nephritis patients had significantly increased plasma eotaxin, TNF-a, interleukin-17-a, interleukin-10, and interleukin-15 as compared to the systemic lupus erythematosus non-nephritis group. Macrophage-derived chemokine, growth regulated oncogene alpha, and epidermal growth factor were significantly elevated in systemic lupus erythematosus non-nephritis patients when compared to lupus nephritis individuals. Plasma eotaxin levels allowed a discrimination between systemic lupus erythematosus non-nephritis and lupus nephritis patients, for which we performed a receiver operating characteristic curve to confirm. We observed a correlation of eotaxin levels with active nephritis (Systemic Lupus Erythematosus Disease Activity Index). Our data indicate that circulating cytokines and chemokines could be considered good predictors of renal involvement in individuals with systemic lupus erythematosus

Tres años con adolescentes en un servicio de salud mental comunitario.

Evaluación de la asistencia a adolescentes durante tres años en el programa infanto juvenil de un servicio de salud mental comunitario. Características de la demanda, intervenciones terapéuticas realizadas y situación asistencial en la que quedan los casos

Tres años con adolescentes en un servicio de salud mental comunitario.

Evaluación de la asistencia a adolescentes durante tres años en el programa infanto juvenil de un servicio de salud mental comunitario. Características de la demanda, intervenciones terapéuticas realizadas y situación asistencial en la que quedan los casos

Diseño, procesamiento y caracterización de laminados de tipo CERMET/WC-CO y WC-CO/WC-CO para aplicaciones de herramientas

Las herramientas para mecanizado de alta velocidad están sometidas a condiciones de servicio extremas y variables, requiriéndose el desarrollo de materiales con composiciones y microestructuras que varíen localmente (función gradiente) según la aplicación. En este trabajo, se presenta un novedoso diseño multicapa con forma de prisma basado en la disposición alternada de capas de cermet y metal duro. Las capas externas de cermet confieren resistencia a la oxidación y al desgaste, mientras que las de WC-Co aportan una mejora de la tenacidad de fractura y de la resistencia a la propagación de grietas. El material laminado debe combinar las capas a distinto estado tensional (tracción o compresión). Se han estimado dos distribuciones de tensiones posibles en el laminado (σR (WC-Co) = -742 MPa y σR (Cermet) = 82,5 MPa) y (σR (WC-Co) = -666 MPa y σR (Cermet) = 166 MPa). Las tensiones de compresión de las capas tenaces y la fuerte intercara actúan como barrera contra la propagación de los defectos presentes o generados en la capa externa.Cutting tools used for high-speed machining are subjected to extreme and variable operating conditions, which requires the development of materials with compositions and microstructures that change locally depending on the application (gradient function). In this work, we propose a novel multilayer design in the shape of prism, based on the alternate arrangement of cermets and hard metals layers. The cermet outer layers provide oxidation and wear resistance, while WC-Co layers improve fracture toughness and crack propagation resistance. The laminate must combine the layers at different stress state (tensile or compressive stress). We calculated two possible stress distributions (σR (WC-Co) = -742 MPa y σR (Cermet) = 82,5 MPa) and (σR (WC-Co)= -666 MPa y σR (Cermet)= 166 MPa). The compression stress acts as a barrier to the propagation of the existing or created defects on the external cermet layers