La participation d'un enseignant stagiaire à la communauté de pratique enseignante lue au travers d'une théorie de l'action collective : éléments théoriques et premiers résultats.

Atelier 28 : Formation des enseignants en général.Cette étude de cas longitudinale s'appuie sur une relecture du concept de " participation " à une communauté de pratique (Lave & Wenger, 1991) par une théorie de l'apprentissage (Nelson, 2008) et de l'action collective (Wittgenstein, 1996). La participation à la communauté est ici davantage envisagée en termes de jeux de langage et de suivi de règles que de négociation de significations entre les acteurs de la communauté. A partir de cette relecture, il s'agit de décrire la trajectoire de participation d'un enseignant stagiaire à la communauté de pratique enseignante, d'identifier l'activité de formation du/(des) formateur(s) pouvant être rattachée à chaque modalité de participation et de préciser les conséquences de cette participation en termes de formation professionnelle pour l'enseignant stagiaire

Effects of the nature of the doping salt and of the thermal pre-treatment and sintering temperature on spark plasma sintering of transparent alumina

A slurry of a-Al2O3 was doped with Mg, Zr and La nitrates or chlorides, in various amounts in the range 150-500 wt ppm and then freeze-dried to produce nanosized doped powder (~150 nm). The powder was sintered by SPS to yield transparent polycrystalline alpha alumina. The influence of the nature of the doping element and the starting salt, the thermal treatment before sintering and the sintering emperature on the transparency of the ceramics were investigated. The transparency of the ceramics of nanosized Al2O3 was shown to depend mainly on the way the powder was prepared, the nature of the doping salt also had an effect. Finally, a high real inline transmittance, reaching 48.1% was achieved after optimization

A new subunit vaccine based on nucleoprotein nanoparticles confers partial clinical and virological protection in calves against bovine respiratory syncytial virus

Human and bovine respiratory syncytial viruses (HRSV and BRSV) are two closely related, worldwide prevalent viruses that are the leading cause of severe airway disease in children and calves, respectively. Efficacy of commercial bovine vaccines needs improvement and no human vaccine is licensed yet. We reported that nasal vaccination with the HRSV nucleoprotein produced as recombinant ringshaped nanoparticles (NSRS) protects mice against a viral challenge with HRSV. The aim of this work was to evaluate this new vaccine that uses a conserved viral antigen, in calves, natural hosts for BRSV. Calves, free of colostral or natural anti-BRSV antibodies, were vaccinated with NSRS either intramuscularly, or both intramuscularly and intranasally using MontanideTM ISA71 and IMS4132 as adjuvants and challenged with BRSV. All vaccinated calves developed anti-N antibodies in blood and nasal secretions and N-specific cellular immunity in local lymph nodes. Clinical monitoring post-challenge demonstrated moderate respiratory pathology with local lung tissue consolidations for the non vaccinated calves that were significantly reduced in the vaccinated calves. Vaccinated calves had lower viral loads than the nonvaccinated control calves. Thus NSRS vaccination in calves provided cross-protective immunity against BRSV infection without adverse inflammatory reaction

A Pilot Study on the Effectiveness of a Heat-Pain Stimulus to induce Pain, Anxiety, and Fear

While the majority of previous studies assessing pain-related variables in psychopaths used electric shocks, little is known about the effectiveness of alternative pain-inducing methods to increase emotional responses such as fear and anxiety. A small sample of healthy undergraduate men (N = 15) was recruited to assess the effectiveness of a heat stimulus to induce pain in an immediate versus delayed punishment paradigm. Although pain catastrophizing, anxiety, and threat of pain did not increase throughout the experiment, participants experienced a significant increase of fear of pain and pain intensity, indicating that the heat stimulus was effective in inducing pain. Furthermore, subjects were slower in initiating the pain stimulus during the first five trials, but no time difference was found during the 15 remaining trials. No correlation was found between psychopathic traits and pain-related variables, with the exception of inconsistent results within the Fearless Dominance factor. Findings are discussed in terms of improvement for a larger scale study involving psychopathic individuals

Homomorphism Polynomials Complete for VP

The VP versus VNP question, introduced by Valiant, is probably the most important open question in algebraic complexity theory. Thanks to completeness results, a variant of this question, VBP versus VNP, can be succinctly restated as asking whether the permanent of a generic matrix can be written as a determinant of a matrix of polynomially bounded size. Strikingly, this restatement does not mention any notion of computational model. To get a similar restatement for the original and more fundamental question, and also to better understand the class itself, we need a complete polynomial for VP. Ad hoc constructions yielding complete polynomials were known, but not natural examples in the vein of the determinant. We give here several variants of natural complete polynomials for VP, based on the notion of graph homomorphism polynomials

Homoepitaxial growth of catalyst-free GaN wires on N-polar substrates

3 pagesInternational audienceThe shape of c-oriented GaN nanostructures is found to be directly related to the crystal polarity. As evidenced by convergent beam electron diffraction applied to GaN nanostructures grown by metal-organic vapor phase epitaxy on c-sapphire substrates: wires grown on nitridated sapphire have the N-polarity ([000math]) whereas pyramidal crystals have Ga-polarity ([0001]). In the case of homoepitaxy, the GaN wires can be directly selected using N-polar GaN freestanding substrates and exhibit good optical properties. A schematic representation of the kinetic Wulff's plot points out the effect of surface polarity

Feodorov, Ioana (dir.), Relations entre les peuples de l’Europe orientale et les chrétiens arabes au xviie siècle : Macaire III Ibn al-Za‘īm et Paul d’Alep (Bucarest, 2012)

Cet ouvrage, coordonné par l’historienne Ioana Feodorov de l’Institut d’Études Européennes de l’Académie roumaine et compilant les contributions présentées lors d’un colloque tenu à Bucarest en septembre 2011, est le premier jalon d’une étude pluridisciplinaire menée par une équipe internationale de chercheurs s’étant donné comme mission, ambitieuse et nécessaire, l’édition et la traduction annotée et intégrale du Journal de voyage du Patriarche Macaire III Ibn al-Za‘īm aux Pays roumains, en ..