The influence of holes in the mechanical properties of EWT solar cells

EWT back contact solar cells are manufactured from very thin silicon wafers. These wafers are drilled by means of a laser process creating a matrix of tiny holes with a density of approximately 125 holes per square centimeter. Their influence in the stiffness and mechanical strength has been studied. To this end, both wafers with and without holes have been tested with the ring on ring test. Numerical simulations of the tests have been carried out through the Finite Element Method taking into account the non-linearities present in the tests. It's shown that one may use coarse meshes without holes to simulate the test and after that sub models are used for the estimation of the stress concentration around the holes

El sistema tributario y la financiación de la Iglesia en España

El presente trabajo analiza los cambios que ha experimentado la posición de la Iglesia ante el sistema tributario desde la aprobación del Acuerdo sobre Asuntos Económicos de 3 de enero de 1979 hasta las recientes modificaciones introducidas en el modelo de financiación religiosa. El Acuerdo establece una serie de beneficios fiscales que conforman lo que habitualmente se conoce como 'financiación indirecta' de la Iglesia. Su vigencia se mantiene en los términos que en su momento acordaron el Estado y la Santa Sede, con las lógicas adaptaciones a la nueva realidad del sistema tributario. Esta circunstancia explica que la mayoría de las previsiones del Acuerdo deban referirse a otras figuras, que ciertas referencias hayan devenido inaplicables y, en fin, que algunos beneficios resulten incompatibles con el Derecho Comunitario, una realidad jurídica a la que era ajeno el ordenamiento español en el momento en que se firmó el Acuerdo. ------ The current work examines tax regime modifications the Catholic Church in Spain has experienced, since the passing of the 'Agreement on Economic Affairs', signed in 1979, up until the recent changes in the Spanish public financial model. The 1979 'Agreement on Economic Affairs' established certain tax benefits in favour of the Church, also usually known as 'indirect financing'. These benefits largely retain their relevance established in 1979 when they were agreed upon between the Spanish Government and the Holy See, but there has been a necessity to adapt them to the new reality of the current tax system. These circumstances explain the fact that today most of the benefit provisions have had to be referred to under different tax categories, while other tax references have become completely inapplicable; and still more benefits have had to be repealed because they were not allowed under European Community Law, a legal reality that had no relevance at the time the Agreement was signed

Effective coping with cyberbullying in boys and girls: the mediating role of self-awareness, responsible decision-making, and social support

There is sufficient evidence on the negative consequences of cyberbullying victimisation depending on the coping styles. Social support seeking is among the most effective strategies for coping with cybervictimisation, but it is scarcely used. The robust Maximum Likelihood (ML) method was used to test the potential mediating role of individual (self-awareness, and responsible decision-making) and contextual variables (self-perceived parental and peer support) in the relationship between cybervictimisation and social support seeking in boys and girls. This cross-sectional study collected data from 1,276 Spanish secondary school students (51.2% boys, 48.8% girls) aged 11-18 (M = 13.88, SD = 1.42). Structural equation modelling (SEM) results pointed out responsible decision-making and self-perceived parental support as relevant mediating factors for girls. By contrast, the model was not significant for boys. These findings highlight the importance of both individual and contextual variables in helping adolescents cope with cyberaggressions, considering gender differences

Role of prethymic cells in acquisition of self-tolerance

The sequential character of T-lymphocyte development as it pertains to the stage at which self-tolerance is acquired was investigated. Three phases were studied, defined here as prethymic, intrathymic, and postthymic as determined by the timing of thymus implantation. The model utilized was the temporal pattern of skin graft rejection in thymusless BALB/c nude mice implanted with allogeneic, C57BL/6J, or syngeneic thymuses before or after skin grafting; in some instances, F(1) hybrid spleen cells were also given to newborns or young adults. These experiments in nude mice showed that, (a) self-tolerance could be established despite the absence of the host’s own haplotype in the implanted thymus; (b) recently emigrated postthymic cells could already discriminate self from non-self; (c) specific neonatal tolerance could be induced in nudes by inoculation of F(1) hybrid cells; (d) nudes showed a higher capacity for induction of neonatal tolerance than did normal littermates. These findings indicate that the process of self-tolerance in the T cell's lineage begins during the prethymic state early in ontogeny

The ConRed Program, an Evidence-based Practice

La vertiginosa incorporación de las TIC a la sociedad y los consecuentes riesgos a los que los menores se enfrentan en Internet y las redes sociales han dejado en evidencia la necesidad de incorporar en el currículum escolar el dominio de los entornos virtuales. En cambio, son escasas las iniciativas en esta dirección y más aún programas rigurosamente evaluados, de modo que sirvan de fundamento para el diseño de las líneas de acción educativa. El programa ConRed está basado en la teoría del comportamiento social normativo y persigue los objetivos de mejorar y reducir problemas como el cyberbullying, la dependencia a Internet y la desajustada percepción del control de la información en las redes sociales, para así potenciar el uso beneficioso de éstas. La evaluación del ConRed se ha desarrollado mediante una metodología cuasi experimental, con un grupo experimental (N=595) y uno cuasi-control (N=298). Del total de los 893 estudiantes, el 45,9% eran chicas y la edad media 13,80 años (DT=1,47). Los resultados positivos de reducción de problemas en el grupo experimental y la ausencia de cambio en el grupo control son muestra de su validez y demuestran que trabajando con toda la comunidad educativa y en colaboración con ella es posible mejorar la calidad de la vida virtual y, por tanto, real de los adolescentes.The incredible force with which ITCs have arrived in society and the consequent risks to children when dealing with the Internet and social networks make it necessary for the domain of virtual environments to be included in the school curriculum. However, the initiatives in this direction are limited and there is a lack of rigorously evaluated programs that might act as a basis for designing educational lines of action. The ConRed Program is based on the theory of normative social behavior and aims to reduce problems such as cyber-bullying and addiction to the Internet and refocus the misadjusted perception of information control in the social networks in order to promote their use in a more beneficial way. The ConRed Program has been evaluated using a quasi-experimental methodology, with an experimental group (N=595) and a quasi-control group (N=298) consisting of 893 students (45.9% girls) with an average age of 13.80 years (SD=1.47). The reduction of problems in the experimental group and the lack of change in the control group is evidence of the program’s validity, and show that by working and collaborating with the whole educational community it is possible to improve the quality of the virtual and, therefore, the real life of adolescents

Optimal behavior of viscoelastic flow at resonant frequencies

The global entropy generation rate in the zero-mean oscillatory flow of a Maxwell fluid in a pipe is analyzed with the aim at determining its behavior at resonant flow conditions. This quantity is calculated explicitly using the analytic expression for the velocity field and assuming isothermal conditions. The global entropy generation rate shows well-defined peaks at the resonant frequencies where the flow displays maximum velocities. It was found that resonant frequencies can be considered optimal in the sense that they maximize the power transmitted to the pulsating flow at the expense of maximum dissipation.Comment: Paper accepted to be published in Phys. Rev.

The Ljapunov-Schmidt reduction for some critical problems

This is a survey about the application of the Ljapunov-Schmidt reduction for some critical problems

Empresa del Ferrocarril de Isabel II, de Santander a Alar del Rey

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201