Sharp-Interface Limit of a Fluctuating Phase-Field Model

We present a derivation of the sharp-interface limit of a generic fluctuating phase-field model for solidification. As a main result, we obtain a sharp-interface projection which presents noise terms in both the diffusion equation and in the moving boundary conditions. The presented procedure does not rely on the fluctuation-dissipation theorem, and can therefore be applied to account for both internal and external fluctuations in either variational or non-variational phase-field formulations. In particular, it can be used to introduce thermodynamical fluctuations in non-variational formulations of the phase-field model, which permit to reach better computational efficiency and provide more flexibility for describing some features of specific physical situations. This opens the possibility of performing quantitative phase-field simulations in crystal growth while accounting for the proper fluctuations of the system.Comment: 21 pages, 1 figure, submitted to Phys. Rev.

A probabilistic model for crystal growth applied to protein deposition at the microscale

A probabilistic discrete model for 2D protein crystal growth is presented. This model takes into account the available space and can describe growing processes of different nature due to the versatility of its parameters which gives the model great flexibility. The accuracy of the simulation is tested against a real protein (SbpA) crystallization experiment showing high agreement between the proposed model and the actual images of the nucleation process. Finally, it is also discussed how the regularity of the interface (i.e. the curve that separates the crystal from the substrate) affects to the evolution of the simulation.Comment: 13 pages, 12 figure

La protección del patrimonio arqueológico en Castilla-La Mancha. Reflexiones sobre la Ley 4/2013 de patrimonio cultural

La nueva Ley 4/2013 ha aportado al panorama arqueológico de Castilla-La Mancha importantes novedades que el autor analiza y comenta desde una óptica personal. La Ley, aprobada la pasada primavera, multiplica los instrumentos jurídicos con que se dota a la Administración competente en la conservación del patrimonio cultural. Asimismo, supone el complemento normativo necesario al innovador Código Deontológico de la Arqueología y Patrimonio de Castilla-La Mancha recientemente aprobado en esta región. Este innovador Código aborda aquellos aspectos que, por implicar más a la ética que a la norma, no son definidos por ést

Epidemiological study of enteric infections in children by comparing different countries

Correlaciones entre muertes por diarrea en niños y parámetros tanto socioeconómicos como ambientales, son estudiadas aquí para 10 países, mostrando asociaciones entre casos y población, lluvia y producto interno bruto (PIB). Las variables correlacionadas incluyen: casos de muerte, población (total y densidad), área (tierra y agua), temperatura promedio, lluvia, productividad, desigualdad de ingreso (índice Gini), indicador de alta tecnología (tecnología de desarrollo de armas nucleares). Cuando se divide en 2 grupos la base de datos: países desarrollados y en desarrollo, algunas asociaciones crecen para los países en desarrollo (R más grandes, p-values <0.05). Las correlaciones encontradas aquí apoyan que el exceso de lluvias y los asentamientos atestados contribuyen a la transmisión de las infecciones; dando a entender que la densidad de población impone un límite práctico en el control de las infecciones entéricas en los países en desarrollo.Correlates among diarrhea-deaths in children, and social and environmental parameters, are studied here for 10 countries, showing significant associations among cases and population, rainfall, and gross domestic product (GDP). The variables correlated include: cases, population (total and density), area (land and water), average temperature, rainfall, productivity (GDP), income inequality (Gini index), and hi-technology indicator (by nuclear weapons technology). When the dataset is split in two sets: developed and developing countries, some of the associations for developing countries grow up (larger R, p-values < 0.05). Correlations found here support that excessive rainfall and crowded settlements contribute to the transmission of infections; hinting that population density imposes a practical boundary in controlling enteric infections in developing countries

Spin precession and spin Hall effect in monolayer graphene/Pt nanostructures

Spin Hall effects have surged as promising phenomena for spin logics operations without ferromagnets. However, the magnitude of the detected electric signals at room temperature in metallic systems has been so far underwhelming. Here, we demonstrate a two-order of magnitude enhancement of the signal in monolayer graphene/Pt devices when compared to their fully metallic counterparts. The enhancement stems in part from efficient spin injection and the large resistivity of graphene but we also observe 100% spin absorption in Pt and find an unusually large effective spin Hall angle of up to 0.15. The large spin-to-charge conversion allows us to characterise spin precession in graphene under the presence of a magnetic field. Furthermore, by developing an analytical model based on the 1D diffusive spin-transport, we demonstrate that the effective spin-relaxation time in graphene can be accurately determined using the (inverse) spin Hall effect as a means of detection. This is a necessary step to gather full understanding of the consequences of spin absorption in spin Hall devices, which is known to suppress effective spin lifetimes in both metallic and graphene systems.Comment: 14 pages, 6 figures. Accepted in 2D Materials. https://doi.org/10.1088/2053-1583/aa882

Testing parameters used in risk quantification of enteric infections

Las infecciones entéricas implican una inmensa carga incluyendo incapacidad, desarrollo deficiente y muerte del huésped. La Organización Mundial de la Salud en 2013 estimo 760,000 muertes en niños menores de 5 años principalmente en el 3er mundo. La evaluación de riesgo de infección permite predicciones que informan a la política ambiental, investigación y aplicación de recursos para prevenir y atacar infecciones. Aquí se trata de evaluar o probar el grado de dependencia de parámetros en las funciones de evaluación de riesgo de infección, mediante la asociación estadística. Los parámetros y variables observadas fueron: la concentración en biosólidos, decaimiento en el ambiente, respuesta a dosis, expresión, y dimensión o tamaño del patógeno. Se encontraron correlaciones estadísticamente significativas entre casos de hospitalizaciones y concentración de gérmenes en biosólidos Clase B y en excreciones. Estos hallazgos sirven de prueba de validación tanto de las ecuaciones como de los parámetros de los modelos de cálculo de riesgo de infección. No se encontraron asociaciones contradictorias.The global burden meant by enteric infections includes incapacities, poorly developed children, ill nutrient absorption, and death of the host; indeed in the year 2013 the World Health Organization reported 760,000 deaths per year in children fewer than 5 years old, mainly in developing countries. The risk quantification of infections informs environmental policy, and research to prevent and to control diseases. This work intends to introduce a simple test for the parameters effect in the risk quantification models, by analyzing the associations between hospitalized cases and: germs concentration in biosolids, decay, dose-response, shedding, and diameter or length of the pathogen. The strong associations found here between hospitalized cases and concentration of germs, in biosolids Class B and concentration in shed masses, between decay rate and dose response parameters, and between decay rate and biosolids concentration, serve as validation test of models and parameters of risk of enteric infection calculations. Interesting to notice that association between cases and concentration of germs in shedding is higher than concentration in biosolids. Here were found not contradictory associations

The ALHAMBRA photometric system

This paper presents the characterization of the optical range of the ALHAMBRA photometric system, a 20 contiguous, equal-width, medium-band CCD system with wavelength coverage from 3500A to 9700A. The photometric description of the system is done by presenting the full response curve as a product of the filters, CCD and atmospheric transmission curves, and using some first and second order moments of this response function. We also introduce the set of standard stars that defines the system, formed by 31 classic spectrophotometric standard stars which have been used in the calibration of other known photometric systems, and 288 stars, flux calibrated homogeneously, from the Next Generation Spectral Library (NGSL). Based on the NGSL, we determine the transformation equations between Sloan Digital Sky Survey (SDSS) ugriz photometry and the ALHAMBRA photometric system, in order to establish some relations between both systems. Finally we develop and discuss a strategy to calculate the photometric zero points of the different pointings in the ALHAMBRA project.Comment: Astronomical Journal on the 14th of January 201