Access to multiliteracies: A critical ethnography

This paper reports the key findings of a critical ethnography, which documented the enactment of the multiliteracies pedagogy in an Australian elementary school classroom. The multiliteracies pedagogy of the New London Group is a response to the emergence of multimodal literacies in contemporary contexts of increased cultural and linguistic diversity. Giddens' structuration theory was applied to the analysis of systems relations. The key finding was that students, who were culturally and linguistically diverse, had differential access to multiliteracies. Existing degrees of access were reproduced among the student cohort, based on the learners' relation to the dominant culture. Specifically, students from Anglo-Australian, middle-class backgrounds had greater access to transformed designing than those who were culturally or socio-economically marginalized. These experiences were influenced by the agency of individuals who were both enabled and constrained by structures of power within the school and the wider educational and social systems

Des actions en faveur de la nature dans les cours d’école : un levier pertinent pour mieux vivre ensemble dans une démarche d’établissement « vers un développement durable »

Dans le cadre des pratiques développées par les classes-ateliers-environnement de Tours (France) qui accompagnent des projets d’éducation à l’environnement avec les écoles primaires, celles qui visent à réintroduire un peu de nature dans les cours des écoles font ici l’objet d’une première analyse. Une exploration bibliographique sur le sujet permet d’argumenter tout l’intérêt de ce type d’actions concrètes, intérêt déjà perçu intuitivement par la communauté éducative sollicitée. Pourtant, une analyse préliminaire de ces actions pédagogiques met en évidence des difficultés à différents niveaux qu’il serait intéressant d’étudier de manière approfondie par la suite. Cet article tend également à montrer qu’une volonté de renaturalisation de l’école pourrait s’avérer une entrée pertinente pour des établissements qui s’engagent dans une démarche de développement durable. En effet, le bien-fondé des actions collectives visant à restaurer un peu de biodiversité dans un espace éducatif informel peut s’ancrer dans un champ philosophique qui explore le thème du mieux-vivre ensemble à l’école.This article analyzes practices developed by environment workshop-classes in Tours (France) that complement environmental education projects in elementary schools. These practices aim to bring a little nature back into the classroom. A bibliographical exploration of the subject shows increased interest in this type of action. The educational community that was approached had already perceived this interest intuitively. However, a preliminary analysis of these pedagogical actions reveals problems at different levels, which would be interesting to study in more depth. The article also attempts to show that the school’s desire to renaturalize could be a relevant port of entry for schools involved in a sustainable development process. The legitimacy of collective actions aimed at restoring a little biodiversity to an informal educational space can be based on a philosophical exploration based on the theme of sharing the planet.En el cuadro de acciones desarrolladas por las clases-talleres-medio-ambiente de Tours (Francia), que acompañan los proyectos de educación relativas al entorno ecológico con escuelas primarias, aquellas que apuntaban la reintroducción de un poco de naturaleza en los cursos constituyen aquí los objetos de un primer análisis. Una exploración bibliográfica sobre el tema permite argumentar el interés de ese tipo de acciones concretas, interés ya percibido intuitivamente por la comunidad educativa solicitada. Sin embargo, el análisis preliminar de dichas acciones pedagógicas pone en evidencia dificultades en diferentes niveles, que sería interesante profundizar posteriormente. Este artículo tiende a mostrar que una voluntad de re-naturalización de la escuela podría ser una entrada apropiada para las escuelas que adhieren al proyecto de desarrollo sustentable. En efecto, lo bien fundado de las acciones colectivas que tratan restaurar un poco de biodiversidad en un espacio educativo informal pueden cimentarse en un campo filosófico que explora el tema de mejorar el vivir juntos en la escuela

Rente naturelle et composition des dépenses publiques

In this paper, we investigate the impact of natural resource rent on public expenditure composition. Our hypothesis is that, when institutional quality is low, politicians have more discretionary power on the allocation of public resources. Then public expenditure composition tends to be modified in favour of two types of public spending : those which generate important political benefits and those which are favoured the most by politicians. We use the model of political-budget cycles developed by Drazen and Eslava (2005a) to support our hypothesis. In this model, politicians try to influence citizens by manipulating public expenditure composition (and not the level of government spending). In the empirical part of this paper, we estimate a fixed effects model in which we explain the share of a type of public expenditure in total public spending by several variables among them we have a measure of natural resource rent. We use rent data compiled by the World Bank and calculate rent from ten raw agricultural products. According to our results, natural resource abundance is associated with higher current expenditure especially subsidies. Natural resource rent seems to have no significant effect on public investment. It is even associated with lower spending on transport and communications (a proxy for investment in public infrastructure)

Unusual structural tuning of magnetism in cuprate perovskites

Understanding the structural underpinnings of magnetism is of great fundamental and practical interest. Se_{1-x}Te_{x}CuO_{3} alloys are model systems for the study of this question, as composition-induced structural changes control their magnetic interactions. Our work reveals that this structural tuning is associated with the position of the supposedly dummy atoms Se and Te relative to the super-exchange (SE) Cu--O--Cu paths, and not with the SE angles as previously thought. We use density functional theory, tight-binding, and exact diagonalization methods to unveil the cause of this surprising effect and hint at new ways of engineering magnetic interactions in solids.Comment: 4 pages, with 4 postscript figures embedded. Uses REVTEX4 and graphicx macro

Rente naturelle et institutions. Les Ressources Naturelles : Une « Malédiction Institutionnelle » ?

Depuis les travaux de Sachs et Warner (1995), la littérature de la malédiction des ressources naturelles identifie un effet négatif de la dotation naturelle sur les performances économiques des pays. Un des mécanismes mis en avant est celui de la mauvaise qualité institutionnelle, les ressources naturelles empêcheraient le développement de « bonnes » institutions favorables au développement économique. Cet article apporte deux éléments au débat. Tout d'abord, il propose une analyse aussi exhaustive que possible des mécanismes reliant ressources naturelles et qualité institutionnelle. Au-delà de la corruption et des comportements de prédation souvent traités dans la littérature, nous analysons le rôle de l'héritage colonial, celui des guerres civiles et de l'instabilité politique, celui des institutions politiques et celui de l'efficacité publique (surtout en termes d'insuffisant développement du système fiscal) et celui des politiques économiques. Dans un deuxième temps, nous procédons à une étude empirique des déterminants de la qualité institutionnelle sur la période 1990-2004 en nous inspirant de l'étude de La Porta et al (1998). Les ressources naturelles sont mesurées par la rente qu'elles génèrent (et non par les exportations comme c'est généralement le cas) et nous distinguons les ressources concentrées (hydrocarbures, minerais, cultures de plantation) et les ressources diffuses (riz, blé, forêt). On montre que, quel que soit l'indicateur institutionnel utilisé, les ressources naturelles concentrées agissent de façon négative sur la qualité institutionnelle. En revanche, les ressources diffuses n'ont généralement pas d'effet significatif (ou alors généralement positif). Les pays les plus pauvres, ceux situés près de l'équateur, ceux disposant d'une forte proportion de catholiques et de musulmans ainsi que ceux ayant une origine légale civile (française) ou socialiste tendent à avoir de moins bonnes institutions (La Porta et al, 1998). En revanche, la fragmentation ethnique n'est pas significative

Rhodium colloidal suspension deposition on porous silica particles by dry impregnation: Study of the influence of the reaction conditions on nanoparticles location and dispersion and catalytic reactivity

Rhodium composite nanomaterials were synthesized by an innovating process called dry impregnation in a fluidized bed. It consists in spraying an aqueous colloidal suspension of rhodium on silica porous particles. The use of this precursor solution containing preformed nanoparticles avoids calcination/activation step. Different composite nanomaterials were prepared displaying various metal loadings. The operating conditions were tuned to modify τs, the solvent vapour saturation rate value, in order to influence the deposit location: either uniform on the whole silica particles or at the particles surface like a coating. τs is defined as the ratio between solvent content in the bed atmosphere and the maximum solvent content. The obtained samples were investigated in catalytic hydrogenation of aromatic compounds under very mild conditions. Their catalytic performances were compared to those of the original colloidal suspension in one hand and of a similar catalyst prepared through wet impregnation in another hand. Interesting activity and selectivity were observed.This illustrates the interest of the dry impregnation method: this way allows an easy control of the metal loading as well as of the metal loading location in the support particles. Moreover, the support particle size and morphology are preserved

Synthesis of Supported Catalysts by Dry Impregnation in Fluidized Bed

The synthesis of catalytic or not composite materials by dry impregnation in fluidized bed is described. This process can be carried out under mild conditions from solutions of organometallic precursors or colloidal solutions of preformed nanoparticles giving rise to reproducible metallic nanoparticles containing composite materials with a high reproducibility. The adequate choice of the reaction conditions makes possible to deposit uniformly the metal precursor within the porous matrix or on the support surface. When the ratio between the drying time and the capillary penetration time (tsec/tcap) is higher than 10, the impregnation under soft drying conditions leads to a homogeneous deposit inside the pores of the particles of support. The efficiency of the metal deposition is close to 100%, and the size of the formed metal nanoparticles is controlled by the pores diameter. Finally, some of the presented composite materials have been tested as catalysts: iron-based materials were used in carbon-nanotubes synthesis, while Pd and Rh composite materials have been investigated in hydrogenation reactions

Dry impregnation in fluidized bed: Drying and calcination effect on nanoparticles dispersion and location in a porous support

The synthesis of metal nanoparticles dispersed inside the grains of a porous inorganic support was carried out by ‘‘dry impregnation’’ in a fluidized bed. The principle of this technique consists in the spraying of a solution containing a metal source into a hot fluidized bed of porous particles. The metal source can be of different nature such as metal salts, organometallic precursors or colloidal solutions. The experimental results obtained from iron oxide deposition on a porous silica gel as support, constitute the core of this article but others results concerning the deposition of rhodium from a colloidal suspension containing preformed rhodium nanoparticles are also described. More precisely, this study aims to understand the effect of the bed temperature during the impregnation step, the initial particle porosity and the calcination operating protocol on the metallic nanoparticles dispersion and location in the silica porous particles. The so-obtained products were characterized by various techniques in order to determine their morphology, their surface properties and the dispersion of the nanoparticles inside the support. The results showed that, under the chosen operating conditions, the deposit efficiency is close to 100% and the competition between the drying rate, depending on the process-related variables, and the capillary penetration rate, depending on the physicochemical-related variables, controls the deposit location. A quasi uniform deposit inside the support particles is observed for soft drying. The metal nanoparticles size is controlled by the pore mean diameter of the support as well as the calcination operating protocol

Model arenes hydrogenation with silica-supported rhodium nanoparticles:The role of the silica grains and of the solvent on catalytic activities

Silica-supported rhodium-based nanoheterogeneous catalysts were easily prepared by impregnation with a pre-stabilized colloidal suspension. The resulting catalysts contain rhodium nanoparticles well-dispersed in the silica pores with a mean size of 5 nm. Influence of the silica grains size and of the solvent was investigated in arenes hydrogenation. It appeared that the size of the silica grains has a minimal influence on the reaction rate but the supported nanocatalysts displayed higher TOFs in hexane than in water