Aspects économiques de la production de parquet massif de chêne vert

La faisabilité économique de la fabrication de parquet en chêne vert, essence très abondante sur le pourtour méditerranéen, a été analysée par le Cirad-Forêt. Le prix de revient global de la transformation a été calculé en se référant à une opération exp

2D numerical model of an ocean/continent subduction system: examples from the Variscan crust

Mechanisms that favor the exhumation of subducted crustal material, both continental and oceanic, have been explored by mean of several models and 2D numerical studies. Petrological and numerical models (e.g. Ernst and Liou, 2008; Roda et al., 2010 and refs. therein) reveal that the dehydration process of the oceanic slab, with a consequent hydration of the mantle wedge, have a primary role for developing a convective dynamics in the area between the slab and the upper plate, since the beginning of the subduction. The geodynamics of a convergent ocean/continent margin, evolving from subduction to continental collision, was analyzed by means of a 2D finite element thermo-mechanical model, in which the physics of the crust-mantle system is described by the equations for continuity, conservation of momentum and conservation of energy. A viscous behavior for the whole system is assumed, with both density and viscosity depending on temperature and composition. Different values of convergence velocities, 3, 5 and 8 cm/yr, have been used, as representative of slow, medium and fast subduction systems, respectively. Our analysis is particularly focused on the effects of viscous heating and mantle hydration on the dynamics in the wedge area. The results support that these mechanisms, differently from our reference model without hydration and viscous heating (Marotta and Spalla, 2007), induce the development of short wavelength convective cells in the wedge area, that favor the exhumation of buried crustal material since the early stages of the subduction. Model predictions, in terms of pressure, temperature, lithology and time, will be compared with structural, petrological and age natural data from the European Variscan crust to check and interactively improve 2D numerical models of the explored ocean/continent subduction system

Effects of mantle hydration and viscous heating on the dynamics of mantle wedge in a subduction system: differences and similarities of 2D model predictions with examples from the Variscan crust

Mechanisms that favor the exhumation of subducted crustal material, both continental and oceanic, have been explored by mean of several models and 2D numerical studies. Petrological and numerical models (e.g. Ernst and Liou, 2008; Roda et al., 2010; Regorda et al., 2013 and refs. therein) reveal that the dehydration process of the oceanic slab, with a consequent hydration of the mantle wedge, have a primary role for developing a convective dynamics in the area between the slab and the upper plate, since the beginning of the subduction. The geodynamics of a convergent ocean/continent margin, evolving from subduction to continental collision, was analyzed by means of a 2D finite element thermo-mechanical model, in which the physics of the crust-mantle system is described by the equations for continuity, conservation of momentum and conservation of energy. A viscous behavior for the whole system is assumed, with both density and viscosity depending on temperature and composition. Different values of convergence velocities, 3, 5 and 8 cm/yr, have been used, as representative of slow, medium and fast subduction systems, respectively. Our analysis is particularly focused on the effects of viscous heating and mantle hydration on the dynamics in the wedge area. The results support that these mechanisms, differently from our reference model without hydration and viscous heating (Marotta and Spalla, 2007), induce the development of short wavelength convective cells in the wedge area, that favor the exhumation of buried crustal material since the early stages of the subduction. Model predictions, in terms of pressure, temperature, lithology and time, will be compared with structural, petrological and age natural data from the European Variscan crust to check and interactively improve 2D numerical models of the explored ocean/continent subduction system

Analisis and tools for performance prediction

We present an analytical model that extends BSP to cover both oblivious synchronization and group partitioning. There are a few oversimplifications in BSP that make difficult to have accurate predictions. Even if the numbers of individual communication or computation operations in two stages are the same, the actual times for these two stages may differ. These differences are due to the separate nature of the operations or to the particular pattern followed by the messages. Even worse, the assumption that a constant number of machine instructions takes constant time is far from the truth. Current memory hierarchies imply that memory access vary from a few cycles to several thousands. A natural proposal is to associate a different proportionality constant with each basic block, and analogously, to associate different latencies and bandwidths with each “communication block”. Unfortunately, to use this approach implies that the evaluation parameters not only depend on given architecture, but also reflect algorithm characteristics. Such parameter evaluation must be done for every algorithm. This is a heavy task, implying experiment design, timing, statistics, pattern recognition and multi-parameter fitting algorithms. Software support is required. We have developed a compiler that takes as source a C program annotated with complexity formulas and produces as output an instrumented code. The trace files obtained from the execution of the resulting code are analyzed with an interactive interpreter, giving us, among other information, the values of those parameters.Eje: Programación concurrenteRed de Universidades con Carreras en Informática (RedUNCI

Analisis and tools for performance prediction

We present an analytical model that extends BSP to cover both oblivious synchronization and group partitioning. There are a few oversimplifications in BSP that make difficult to have accurate predictions. Even if the numbers of individual communication or computation operations in two stages are the same, the actual times for these two stages may differ. These differences are due to the separate nature of the operations or to the particular pattern followed by the messages. Even worse, the assumption that a constant number of machine instructions takes constant time is far from the truth. Current memory hierarchies imply that memory access vary from a few cycles to several thousands. A natural proposal is to associate a different proportionality constant with each basic block, and analogously, to associate different latencies and bandwidths with each “communication block”. Unfortunately, to use this approach implies that the evaluation parameters not only depend on given architecture, but also reflect algorithm characteristics. Such parameter evaluation must be done for every algorithm. This is a heavy task, implying experiment design, timing, statistics, pattern recognition and multi-parameter fitting algorithms. Software support is required. We have developed a compiler that takes as source a C program annotated with complexity formulas and produces as output an instrumented code. The trace files obtained from the execution of the resulting code are analyzed with an interactive interpreter, giving us, among other information, the values of those parameters.Eje: Programación concurrenteRed de Universidades con Carreras en Informática (RedUNCI

Students factors affecting undergraduates perceptions of their teaching and learning process within ECTS experience

Introduction: In the present study, we investigated the potential factors that influenced the level of students satisfaction with the teaching¿learning process (TLP), from the perspective of students participating in the European Credit Transfer System (ECTS) experience. Method: A total of 1490 students from the Universities of Almería and Granada (Spain) participated in an evaluation of their class discipline area. They completed the new revised protocol for evaluating the ECTS experience. Analyses of variance were carried out, taking the following factors as independent variables: student¿s grade average, year in school, study discipline, credit load in terms of ECTS credits assigned to a subject, the e-learning approach. Perception of the TLP was used as the dependent variable. Results: The data analyses showed variability of the degree of statistically significance among the factors that influenced students¿ perceptions of the TLP. These factors included: Student¿s grade average (in favor of high performers), year in school (in favor of earlier years), ECTS load (in favor of subjects with a medium load of credits), and e-learning (in favor of its use). These research findings provided evidence to explore the delineation of a potential profile of factors that trigger a favorable perception of the TLP. Discussion and Conclusion: The present findings certainly have implications to deepen our understanding of the core beliefs, commitment, and the experience in shaping the implementation of the European Higher Education Area through the ECTS

Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method

This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known $e/h$ ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within $\pm 1$ of the true values and the fractional energy resolution is $[(58\pm3)/\sqrt{E}+(2.5\pm0.3)$. The value of the $e/h$ ratio obtained for the electromagnetic compartment of the combined calorimeter is $1.74\pm0.04$ and agrees with the prediction that $e/h > 1.7$ for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio