La fracture en France est encore plus forte à gauche

L’affaire grecque divise toute la classe politique. Mais comme en Italie et en Espagne, la fracture en France est encore plus forte à gauche, une partie du PS tombant d’accord avec le Front de gauche pour exprimer sa solidarité avec Tsípras et glorifier l’attitude du peuple grec. L’intensité de ce débat atteste de la prégnance dans la culture française de la gauche radicale. Au travers du cas grec, on retrouve ses thématiques historiques : l’affirmation d’une solidarité internationale, dont la traduction au moment de la guerre d’Espagne fut son soutien aux républicains espagnols ; d’une solidarité aussi avec les peuples en souffrance, qui raisonne avec le tropisme très fort en France du complexe de David contre Goliath. On retrouve aussi l’hostilité au libéralisme, ce que l’on appelait l’anticapitalisme ; la critique de l’Europe, une constante de la gauche radicale, non pas au nom de l’anti-européanisme mais au nom de la construction d’«une autre Europe» plus sociale ; et puis enfin la célébration de la démocratie directe, référendaire. [Premier paragraphe

Porous Gold Films Fabricated by Wet-Chemistry Processes

Porous gold films presented in this paper are formed by combining gold electroless deposition and polystyrene beads templating methods. This original approach allows the formation of conductive films (2 × 106 (Ω·cm)−1) with tailored and interconnected porosity. The porous gold film was deposited up to 1.2 μm on the silicon substrate without delamination. An original zirconia gel matrix containing gold nanoparticles deposited on the substrate acts both as an adhesion layer through the creation of covalent bonds and as a seed layer for the metallic gold film growth. Dip-coating parameters and gold electroless deposition kinetics have been optimized in order to create a three-dimensional network of 20 nm wide pores separated by 20 nm thick continuous gold layers. The resulting porous gold films were characterized by GIXRD, SEM, krypton adsorption-desorption, and 4-point probes method. The process is adaptable to different pore sizes and based on wet-chemistry. Consequently, the porous gold films presented in this paper can be used in a wide range of applications such as sensing, catalysis, optics, or electronics

Chemical evolution of Titan's tholins exposed to solar radiation in Low Earth Orbit onboard the EXPOSE facility and possible incidence on Titan's aerosols composition (Screen 5)

International audienceWith the objective to characterize the aging of Titan's aerosols produced in the upper atmosphere and submitted to solar radiation during their long descent to the satellite surface, Titan's tholins were exposed to the direct solar radiation in low Earth orbit using the ESA's EXPOSE facility that was mounted outside the ISS for months. The interest of such an experiment comes from the exposure of the sample to the real solar radiation spectrum. Two varieties of tholins with different chemical properties were produced with the PAMPRE laboratory experiment, one using a (98:2) N2:CH4 gaseous mixture, and another one with a (90:10) mixture. These samples were exposed to the same solar radiation for the months the EXPOSE facility was mounted outside ISS. Their chemical properties measured before the flight and after their return to the laboratory were compared. Results clearly show that both tholins structure have been modified by the solar radiation. Thanks to control samples placed in the EXPOSE facility in blind cells, and in a facility in the laboratory, this evolution can be definitely attributed to UV radiation. We present here the corresponding results and the consequences we can deduce for the aging of the Titan'

Chemical Aging of Titan's Tholins Exposed to Solar Radiation in Low Earth Orbit onboard the EXPOSE Facility

International audienceTitan's organic aerosols are produced from the chemistry occurring in the atmosphere from gaseous N2 and CH4 submitted to UV solar radiation and energetic particles from Saturn magnetosphere. Our direct knowledge about their chemical composition is limited but we know they are among the most complex organic materials on Titan, composed of a solid core incorporating at least both carbon, hydrogen and nitrogen atoms. This chemistry is unique in the solar system and it could help understanding pathways of the prebiotic chemistry that resulted in the emergence of life. Titan's aerosols composition is indirectly studied through the production and analysis of analogues, called tholins, using laboratory experiments which mimic Titan's atmosphere chemistry conditions. But usually, these tholins are analyzed straight after their production, and it is only recently that the question of their aging was raised. In particular, the aging of the Titan's aerosols submitted to solar radiation during their long descent to the satellite surface was studied in the laboratory using specific UV wavelengths (1). With the same objective, Titan's tholins were exposed to the direct solar radiation in low Earth orbit using the ESA's EXPOSE facility mounted outside the ISS for months. Two varieties of tholins with different chemical properties were produced with the PAMPRE laboratory experiment (2), the first one using a (98:2) N2:CH4 gaseous mixture, and the other one, a (90:10) one. Increasing the amount of initial methane results in a more aliphatic material. These samples were exposed to the same solar radiation for the months the EXPOSE facility was mounted outside ISS. The chemical properties of these samples measured before the flight and after their return to the laboratory were compared. They clearly showed that both tholins structure have been modified in some extent by the solar radiation. Thanks to control samples placed in the EXPOSE facility in blind cells, and in a facility in the laboratory, this evolution can be definitely attributed to UV radiation. We present here the corresponding results and the consequences we can deduce for the aging of the Titan's aerosols Ref:[1]Carrasco N.(2018) Nat. Ast. [2] Szopa C. (2005) Planet. Space Sci

The AMINO experiment: methane photolysis under Solar VUV irradiation on the EXPOSE-R facility of the International Space Station

International audienceThe scientific aim of the present campaign is to study the whole chain of methane photo-degradation, as initiated by Solar vacuum-ultraviolet irradiation in Titan's atmosphere. For this purpose, the AMINO experiment on the EXPOSE-R mission has loaded closed cells for gas-phase photochemistry in space conditions. Two different gas mixtures have been exposed, named Titan 1 and Titan 2, involving both N2-CH4 gas mixtures, without and with CO2, respectively. CO2 is added as a source of reactive oxygen in the cells. The cell contents were analysed thanks to infrared absorption spectroscopy, gas chromatography and mass spectrometry. Methane consumption leads to the formation of saturated hydrocarbons, with no detectable influence of CO2. This successful campaign provides a first benchmark for characterizing the whole methane photochemical system in space conditions. A thin film of tholin-like compounds appears to form on the cell walls of the exposed cells

Recherche, politique et pratiques en éducation : services rendus et questions posées d’un univers à l’autre

À l’occasion de son 200e numéro, la Revue française de pédagogie, revue généraliste de recherche en éducation de référence dans le monde francophone, a souhaité renouer avec l’une des interrogations fondamentales qui la caractérisent depuis sa création en 1967 : celle des rapports entre recherche, politique, administration et pratique professionnelle en éducation. Fondé sur un appel à contributions inédit, ce numéro a la particularité de ne pas regrouper uniquement des articles émanant de chercheurs, mais de croiser ceux-ci avec des contributions d’acteurs aux profils divers. Les analyses présentées permettent ainsi de couvrir une grande diversité de situations nationales et institutionnelles, notamment : rôle et fonctionnement de différents « Conseils supérieurs » en France ou au Québec, débats et controverses médiatiques et scientifiques à propos d’une loi sur « l’école inclusive » en République tchèque, construction de séquences didactiques fondées sur la recherche au Mexique, accompagnement d’établissements scolaires par la recherche dans le canton de Vaud en Suisse ou encore place de la recherche dans des revues d’interface. Deux axes majeurs structurent le numéro : l’étude de divers espaces, supports ou acteurs assurant une fonction de médiation entre les univers étudiés ; l’analyse de la place et des transformations de la recherche en contexte non strictement académique (situations d’expertise ou de formation par exemple). En cela, ce numéro apporte une contribution fondamentale aux nombreux questionnements actuels sur les rôles et la structuration de la recherche en éducation dans une société dite de la connaissance. For its 200th issue, the Revue française de pédagogie, a generalist journal of research in education and one of the leading publication on the subject in the French-speaking world, decided to take a fresh look at one the fundamental questions which have defined it since it was first published in 1967: the relationship between academic research, politics, administration and professional practice in education. Based on a new call for papers, this issue consists of articles by scholars and contributions from stakeholders from a range of backgrounds (experts, policy makers, activists etc.). The articles cover a wide variety of domestic and institutional situations including: the role and functioning of “High Councils” for education in France and Quebec; media and academic debate and controversy surrounding an "inclusive education" law in the Czech Republic; the design of teaching sequences in Mexico; research-based support for schools in the Swiss canton of Vaud; or the place of research in some professional journals which interface with the academic world. Two main themes run through the issue: the study of various spaces, resources or stakeholders which perform a mediating role between academic research and other areas, and the analysis of the place of and changes in research in a non-academic context (expertise or training situations, for instance). In this regard, this issue makes a significant contribution to the many current studies on the role of academic research and how it is organised in a so-called knowledge society