Near-barrier Fusion Induced by Stable Weakly Bound and Exotic Halo Light Nuclei

The effect of breakup is investigated for the medium weight $^{6}$Li+$^{59}$Co system in the vicinity of the Coulomb barrier. The strong coupling of breakup/transfer channels to fusion is discussed within a comparison of predictions of the Continuum Discretized Coupled-Channels model which is also applied to $^{6}$He+$^{59}$Co a reaction induced by the borromean halo nucleus $^{6}$He.Comment: 6 pages, 3 figures. A talk given at the FUSION06: International Conference on Reaction Mechanisms and Nuclear Structure at the Coulomb barrier, March 19-23, 2006, San Servolo, Venezia, Ital

Lesiones en tenistas:percepción subjetiva sobre la importancia de los factores causales

The purpose of this study is to ascertain the importance attached by the players to factors that may cause sports injuries, in terms of being or not being injured. The sample consisted of 63 male tennis players with a mean age of 31.62 years (SD 8.93). The questionnaire used to assess the perception of the degree of importance of different factors as causes of injury. The results indicate that the injured players are placing more emphasis on preventive measures to causation of injuries than non-injured, those who have never been injured, placing more importance on the psychological, that the players who have suffered one or more lesions ; to analyze whether the number of injuries suffered in any way affect the importance given to the factors as a cause of injury, the results indicate that only seems to affect the psychological factor, reducing the importance attached by increasing the number of injuries.El propósito del presente trabajo es conocer la importancia concedida por los tenistas a los factores que pueden provocar lesiones deportivas, en función de estar o no estar lesionados. La muestra estuvo compuesta por 63 jugadores varones de tenis con una media de edad de 31,62 años (d.t. 8,93). Se utilizó un cuestionario para evaluar la percepción del grado de importancia que tienen de diferentes factores como causa de lesiones. Los resultados indican que los tenistas lesionados conceden más importancia a las medidas preventivas en la causación de lesiones, que los no lesionados; los que nunca se han lesionado, conceden más importancia a los aspectos psicológicos, que los tenistas que han sufrido una o más lesiones; al analizar si el número de lesiones sufridas afecta de alguna manera a la importancia concedida a los factores como causa de lesión, los resultados señalan que sólo parece afectar al factor psicológico, reduciendo la importancia concedida según aumenta el número de lesiones

Predicción del rendimiento académico en las nuevas titulaciones de grado de la EPS de la Universidad de Córdoba

En este artículo se describe una experiencia de innovación docente que tiene como finalidad predecir el rendimiento académico de los estudiantes de primer curso de grado universitario utilizando técnicas de minería de datos. La investigación se ha realizado utilizando información de los alumnos de tres asignaturas de introducción a la informática que se han impartido durante el primer cuatrimestre del curso 2010-11 en las distintas titulaciones de grado de la Escuela Politécnica Superior de la Universidad de Córdoba.SUMMARY -- In this paper, we describe an educational innovation experience about the prediction of the students’ academic performance during the first year of university degree by applying data mining techniques. The research has been carried out by using the information of students of three subjects about introduction to computer science during the first semester of 2010-11 academic year in the different degrees of the Higher Technical College of the University of Cordoba.Peer Reviewe

On the relative efficacy of electropermeation and isothermal desorption approaches for measuring hydrogen diffusivity

The relative efficacy of electrochemical permeation (EP) and isothermal desorption spectroscopy (ITDS) methods for determining the hydrogen diffusivity is investigated using cold-rolled pure iron. The diffusivities determined from 13 first transient and 8 second transient EP experiments, evaluated using the conventional lag and breakthrough time methods, are compared to the results of 10 ITDS experiments. Results demonstrate that the average diffusivity is similar between the second EP transient and ITDS, which are distinctly increased relative to the first EP transient. However, the coefficient of variation for the ITDS experiments is reduced by 2 and 3-fold relative to the first and second EP transients, confirming the improved repeatability of ITDS diffusivity measurements. The source of the increased error in EP measurements is systematically evaluated, revealing an important influence of assumed electrochemical boundary conditions on the analysis and interpretation of EP experiments

Binary reaction decays from 24Mg+12C

Charged particle and gamma decays in 24Mg* are investigated for excitation energies where quasimolecular resonances appear in 12C+12C collisions. Various theoretical predictions for the occurence of superdeformed and hyperdeformed bands associated with resonance structures with low spin are discussed within the measured 24Mg* excitation energy region. The inverse kinematics reaction 24Mg+12C is studied at E_lab(24Mg) = 130 MeV, an energy which enables the population of 24Mg states decaying into 12C+12C resonant break-up states. Exclusive data were collected with the Binary Reaction Spectrometer in coincidence with EUROBALL IV installed at the VIVITRON Tandem facility at Strasbourg. Specific structures with large deformation were selectively populated in binary reactions and their associated gamma decays studied. Coincident events associated with inelastic and alpha-transfer channels have been selected by choosing the excitation energy or the entry point via the two-body Q-values. The analysis of the binary reaction channels is presented with a particular emphasis on 24Mg-gamma, 20Ne-gamma and 16O-gamma coincidences. New information (spin and branching ratios) is deduced on high-energy states in 24Mg and 16O, respectively.Comment: 27 pages, 8 figures, 1 tabl

Simulation of hydrogen permeation through pure iron for trapping and surface phenomena characterisation

There is a need for numerical models capable of predicting local accumulation of hydrogen near stress concentrators and crack tips to prevent and mitigate hydrogen assisted fracture in steels. The experimental characterisation of trapping parameters in metals, which is required for an accurate simulation of hydrogen transport, is usually performed through the electropermeation test. In order to study grain size influence and grain boundary trapping during permeation, two modelling approaches are explored; a 1D Finite Element model including trap density and binding energy as input parameters and a polycrystalline model based on the assignment of a lower diffusivity and solubility to the grain boundaries. Samples of pure iron after two different heat treatments - 950C for 40 minutes and 1100C for 5 minutes - are tested applying three consecutive rising permeation steps and three decaying steps. Experimental results show that the finer grain microstructure promotes a diffusion delay due to grain boundary trapping. The usual methodology for the determination of trap densities and binding energies is revisited in which the limiting diluted and saturated cases are considered. To this purpose, apparent diffusivities are fitted including also the influence of boundary conditions and comparing results provided by the constant concentration with the constant flux assumption. Grain boundaries are characterised for pure iron with a binding energy between 37.8 and 39.9 kJ/mol and a low trap density but it is numerically demonstrated that saturated or diluted assumptions are not always verified, and a univocal determination of trapping parameters requires a broader range of charging conditions for permeation. The relationship between surface parameters, i.e. charging current, recombination current and surface concentrations, is also studied

Ternary cluster decay within the liquid drop model

Longitudinal ternary and binary fission barriers of $^{36}$Ar, $^{56}$Ni and $^{252}$Cf nuclei have been determined within a rotational liquid drop model taking into account the nuclear proximity energy. For the light nuclei the heights of the ternary fission barriers become competitive with the binary ones at high angular momenta since the maximum lies at an outer position and has a much higher moment of inertia.Comment: Talk presented at the 9th International Conference on Clustering Aspects of Nuclear Structure and Dynamics (CLUSTERS'07