Les graphes argumentatifs interactifs sur Internet : sont-ils plus efficaces comme média du débat ou comme moyens de le représenter ?

Nous présentons les résultats d'une expérience menée dans le cadre du projet européen SCALE. Le but de cette recherche était d'étudier l'influence du type d'utilisation du graphe argumentatif durant des débats pédagogiques sur Internet. Précisément, il s'agissait de savoir sur le graphe argumentatif était plus efficace lorsqu'il était utilisé comme médium du débat (C1) ou comme moyen de le représenter (C2). Dans cet objectif, nous avons évalué à l'aide d'une méthode originale (ADAM), les différences entre des graphes argumentatifs construits individuellement avant et après le débat, et avons comparé ces différences entre les deux conditions expérimentales. Les résultats suggèrent une complémentarité entre les deux types d'utilisation des graphes argumentatifs dans le cadre d'un apprentissage conceptuel centré sur des questions socialement vives

Two massive star-forming regions at early evolutionary stages

We report sensitive ATCA radio-continuum observations toward IRAS 15596-5301 and 16272-4837, two luminous objects (> 2x10^4 Lsun) thought to represent massive star-forming regions in early stages of evolution (due to previously undetected radio emission at the 1-sigma level of 2 mJy per beam). Also reported are 1.2-millimeter continuum and a series of molecular-line observations made with the SEST telescope. For IRAS 15596-5301, the observations reveal the presence of three distinct compact radio-continuum sources associated with a dense molecular core. We suggest that this core contains a cluster of B stars which are exciting compact HII regions that are in pressure equilibrium with the dense molecular surroundings. No radio continuum emission was detected from IRAS 16272-4837 (3-sigma limit of 0.2 mJy). However, a dense molecular core has been detected. The high luminosity and lack of radio emission from this massive core suggests that it hosts an embedded young massive protostar that is still undergoing an intense accretion phase. This scenario is supported by the observed characteristics of the line profiles and the presence of a bipolar outflow detected from observations of the SiO emission. We suggest that IRAS 16272-4837 is a bona fide massive star- forming region in a very early evolutionary stage, being the precursor of an ultra compact HII region.Comment: 25 pages, 9 figures, accepted for publication in The Astrophysical Journa

Near-infrared and Millimeter-wavelength Observations of Mol 160: A Massive Young Protostellar Core

We have discovered two compact sources of shocked H2 2.12-micron emission coincident with Mol 160 (IRAS 23385+6053), a massive star-forming core thought to be a precursor to an ultracompact HII region. The 2.12-micron sources lie within 2" (0.05 pc) of a millimeter-wavelength continuum peak where the column density is >= 10e24 cm$^{-2}$. We estimate that the ratio of molecular hydrogen luminosity to bolometric luminosity is > 0.2%, indicating a high ratio of mechanical to radiant luminosity. CS J=2-1 and HCO$^+$ J=1-0 observations with CARMA indicate that the protostellar molecular core has a peculiar velocity of ~ 2 km s$^{-1}$ with respect to its parent molecular cloud. We also observed 95 GHz CH3OH J=8$-7 Class I maser emission from several locations within the core. Comparison with previous observations of 44-GHz CH3OH maser emission shows the maser sources have a high mean ratio of 95-GHz to 44-GHz intensity. Our observations strengthen the case that Mol 160 (IRAS 23385+6053) is a rapidly accreting massive protostellar system in a very early phase of its evolution.Comment: 47 pages, 8 figures, 2 tables, accepted for publication in ApJ, 7 Dec 201

Finite element modeling of dynamic frictional rupture with rate and state friction

Numerous laboratory experiments have demonstrated the dependence of the friction coefficient on the interfacial slip rate and the contact history, a behavior generically called rate and state friction. Although numerical models have been widely used for analyzing rate and state friction, in general they consider infinite elastic domains surrounding the sliding interface and rely on boundary integral formulations. Much less work has been dedicated to modeling finite size systems to account for interactions with boundaries. This paper investigates rate and state frictional interfaces in the context of finite size systems with the finite element method in explicit dynamics. We investigate the long term behavior of the sliding interface for two different friction laws: a velocity weakening law, for which the friction monotonously decreases with increasing sliding velocity, and a velocity weakening-strengthening law, for which the friction coefficient first decreases but then increases above a critical velocity. We show that for both friction laws at finite times, that is before wave reflections from the boundaries come back to the sliding interface, a temporary steady state sliding is reached, with a well-defined stress drop at the interface. This stress drop gives rise to a stress concentration and leads to an analogy between friction and fracture. However, at longer times, that is after multiple wave reflections, the stress drop is essentially zero, resulting in losing the analogy with fracture mechanics. Finally, the simulations reveal that velocity weakening is unstable at long time scales, as it results in an acceleration of the sliding blocks. On the other hand, velocity weakening-strengthening reaches a steady state sliding configuration

Finite element model updating of a semi‐rigid moment resisting structure

Partial-strength composite steel–concrete moment-resisting frame structures can be designed to develop a ductile response in components of beam-to-column joints and column bases, including flexural yielding of beam end plates, shear yielding of column web panel zones and yielding of anchors. To evaluate the performance of a statically indeterminate structure under different earthquake intensities, a series of pseudo-dynamic, quasi-static cyclic and vibration tests were carried out at the European Laboratory for Structural Assessment of the Joint Research Centre at Ispra, Italy. The identified modal parameters from forced vibration tests at three different damage levels were used in order to quantify local and global damage indices by updating a 3D FE model of the structure with the non-linear Powell's Dog-Leg optimization method. Then, the Latin Hypercube Sampling technique, a variant of the Monte Carlo method, was employed to study the sensitivity of the updated parameters of the 3D model to modal inputs, caused by measurement noise. Rotations of beam-to-column joints and column bases, storey displacements and forces were employed during the final cyclic test in order to update a 2D FE model of the test structure. To avoid numerical instabilities during the detection of the non-linear behaviour of the structure, a novel technique based on the transformation of the origin coordinates in each half cycle was implemented. The identified joint behaviours allowed low-cycle fatigue energy-based damage indices to be applied. Copyright © 2009 John Wiley & Sons, Ltd

Decrease in the prevalence of paediatric adiposity in Switzerland from 2002 to 2007

Abstract Objective A national study in Switzerland in 2002 suggested nearly one in five schoolchildren was overweight. Since then, many programmes have been introduced in an attempt to control the problem. The aim of the present study was to determine the prevalence of childhood overweight in Switzerland five years later. Design In both studies a cross-sectional, three-stage, probability-proportional-to-size cluster sampling of schools throughout Switzerland was used to obtain a representative sample of approximately 2500 children aged 6-13 years. Height and weight were measured and BMI calculated. The BMI references from the Centers for Disease Control and Prevention were used to determine the prevalences of underweight (100 000 compared with smaller communities (P < 0·05). Conclusions In summary, over the past 5 years, the prevalence of adiposity has decreased in Swiss children. These findings suggest that increased awareness combined with mainly school-based programmes aimed at physical activity and healthy nutrition may have helped to control this public health problem. Future monitoring in Switzerland will determine if these findings are sustaine

Passage Re-Ranking in Live QA NLP Pipelines with BERT

Passage ranking and document ranking are two common tasks in NLP. Many state of the art pipelines use BM25 to retrieve passages. The top results of this ranking are then re-ranked using a BERT transformer trained on the MS MARCO Passage data set. This system and variations have proved highly effective. In addition, questions and answers using BERT are also well explored topics. However, these systems are fundamentally limited by speed and resource consumption requirements. Given an arbitrary corpus and a collection of pre-trained models, we would like to prove that it is possible to create a live Question Answering machine without fine tuning for a particular topic. In particular, we employ a BERT re-ranker to find the first acceptable fit to pass to our QA transformer. This approach is fundamentally different from past research in that it is focused on first fit and not best fit. The goal of this research is to allow anyone to employ off the shelf components to create an effective, interactive question answering system

Densification of classic and fragile ferroelectrics by Cool-SPS

This presentation will illustrate the investigation by Cool-SPS (Spark Plasma Sintering) of the sintering of fragile ferroelectric materials. The efficiency of this advanced technique to sinter, stabilize or even synthetize fragile materials has been established by previous studies conducted at ICMCB [1,2]. Please click Additional Files below to see the full abstract