Generation of a porous scaffold with a starting composition in the CaO-SiO2-MgO-P2O5 system in a simulated physiological environment

Magnesium-based ceramics are involved in orthopedic applications such as bone scaffolds or implant coatings. They provide structural support to cells for bone ingrowth, but highly porous matrices cannot resist severe mechanical stress during implantation. In this study, the laser floating zone (LFZ) technique is used to prepare a dense crystalline material with composition in the CaO-SiO2-MgO-P2O5 system. This material, under physiological conditions, is able to generate a porous scaffold controlled by the dissolution of the MgO phase, meeting the mechanical advantages of a dense material and the biological features of a porous scaffold. FESEM (Field emission scanning electron microscopy), XRD (X-ray Diffraction), EDS (Energy Dispersive X-rays spectroscopy), and ICP ((Inductively Coupled Plasma) analysis were carried out in order to characterize the samples before and after immersion in simulated body fluid (SBF)

Un Nuevo modelo de estilos de aprendizaje: el aprendizaje preferencial complementario

El aprendizaje preferencial complementario es un nuevo modelo de estilos necesario para conocer la forma de aprender del alumno, proporcionar una atención individualizada por perfil y, en general, mejorar el proceso de enseñanza-aprendizaje. Todos los estilos que lo componen están presentes en la naturaleza de cada individuo, pero sólo uno de ellos es preferencial y describe el rol desarrollado por éste cuando aprende. Cuando un grupo de personas, cada una experta en un rol, cooperan para lograr un conocimiento lo hacen de forma complementaria, cada una siguiendo un ciclo análogo al del grupo, aunque con un resultado parcial diferente. Se ha desarrollado un proyecto de Innovación Educativa para estudiantes de Informática aplicando el modelo propuesto a dos grupos reducidos con resultados altamente satisfactorios, no sólo académicos sino también colaborativos y de sinergia entre los miembros del equipo. Seguiremos investigando y profundizando en este modelo ya que día a día descubrimos algo nuevo de cada estilo.Peer Reviewe

Magnetic field production during preheating at the electroweak scale

We study the generation of magnetic fields during preheating within an scenario of hybrid inflation at the electroweak (EW) scale. We find that the non-perturbative and strongly out-of-equilibrium process of magnetic field production occurs along the lines predicted by Vachaspati many years ago. The system starts in the false vacuum at the end of inflation, and very quickly the initial quantum fluctuations of the Higgs field get amplified via long wavelength spinodal instabilities. The subsequent nucleation of the random Gaussian Higgs field bubbles (lumps) leads to EW symmetry breaking, and to the creation of $Z$-strings, which soon decay, along with longwave magnetic flux tubes with nontrivial helicity. The intensity and scales in these helical magnetic fields are consistent with their later development into the microgauss fields observed in galaxies and clusters of galaxies.Comment: 4 pages, 6 figures, uses revtex

Simulations of Cold Electroweak Baryogenesis: Finite time quenches

The electroweak symmetry breaking transition may supply the appropriate out-of-equilibrium conditions for baryogenesis if it is triggered sufficiently fast. This can happen at the end of low-scale inflation, prompting baryogenesis to occur during tachyonic preheating of the Universe, when the potential energy of the inflaton is transfered into Standard Model particles. With the proper amount of CP-violation present, the observed baryon number asymmetry can be reproduced. Within this framework of Cold Electroweak Baryogenesis, we study the dependence of the generated baryon asymmetry on the speed of the quenching transition. We find that there is a separation between ``fast'' and ``slow'' quenches, which can be used to put bounds on the allowed Higgs-inflaton coupling. We also clarify the strong Higgs mass dependence of the asymmetry reported in a companion paper (hep-ph/0604263).Comment: 18 pages, 20 figure

Indicators of the quality of the foster care

Una de las dificultades en la selección de las familias que se acercan al acogimiento familiar está relacionado con la falta de estudios que pudieran apuntar hacia características necesarias que apoyaran un desarrollo integral y comunitario óptimo del menor acogido y a su vez, en el proceso acogedor ayudar tanto a la familia como al menor para generar y/u optimizar aquellos recursos que permitan la consecución de las mismas. En una muestra de 53 familias que a lo largo tres años acogieron a 80 menores nuestro objetivo fue identificar las características que más habían favorecido el desarrollo del menor. Los resultados subrayan la importancia del establecimiento de vínculos seguros del menor con los acogedores, la integración del menor en la familia acogedora (la aparición de un sentido de pertenencia), la existencia de hijos en el núcleo de convivencia y una percepción de satisfacción con el acogimiento, por parte de la familia acogedora.One of the difficulties in choosing the families who come to foster care is related to the lack of studies that indicate the features needed to support optimal integrated development of children in foster care and also help in the process both the family as the child to generate the necessary resources. The sample consisted of 53 families with 80 children in foster care for three years. The aim was to identify characteristics that allow promote the development of the child. The results underline the importance of establishing secure links between the child and the foster family, the integration of the child in the foster family (the emergence of a sense of belonging), the existence of children in the foster family and a sense of satisfaction with welcoming, by the foster family.peerReviewe

New RPC front-end electronics for hades

Time-of-flight (TOF) detectors are mainly used for both particle identification and triggering. Resistive Plate Chamber (RPC) detectors are becoming widely used because of their excellent TOF capabilities and reduced cost. The new ESTRELA* RPC wall, which is being installed in the HADES detector at Darmstadt GSI, will contain 1024 RPC modules, covering an active area of around 7 m2. It has excellent TOF and good charge resolutions. Its Front-End electronics is based on a 8-layer Mother-Board providing impedance matched paths for the output signals of each of the eight 4-channel Daughter-Boards to the TDC

Research on nonlinear and quantum optics at the photonics and quantum information group of the University of Valladolid

We outline the main research lines in Nonlinear and Quantum Optics of the Group of Photonics and Quantum Information at the University of Valladolid. These works focus on Optical Solitons, Quantum Information using Photonic Technologies and the development of new materials for Nonlinar Optics. The investigations on optical solitons cover both temporal solitons in dispersion managed fiber links and nonparaxial spatial solitons as described by the Nonlinear Helmholtz Equation. Within the Quantum Information research lines of the group, the studies address new photonic schemes for quantum computation and the multiplexing of quantum data. The investigations of the group are, to a large extent, based on intensive and parallel computations. Some associated numerical techniques for the development of the activities described are briefly sketched