Oser connaître et reconnaître. Conditions épistémologiques, politiques, éthiques, de la pensée critique à l’école

Les conflits de vérités auxquels les enseignants sont confrontés dans les classes ont de multiples figures et sont d’une actualité brûlante : dénis de faits, complotisme, extrémismes… Ils relèvent de problèmes épistémologiques, politiques, éthiques, contemporains. À la crise de la rationalité occidentale, aux revendications d’identités s’ajoute l’exposition massive des jeunes esprits aux propagandes les plus obscurantistes. L’introduction présente le dossier, dont les articles attestent de ces préoccupations, proposent des élucidations, analysent des situations de classe, suggèrent des orientations pédagogiques. Soutenir chez les élèves l’usage de leur raison ne va pas sans une attention portée à la dimension émotionnelle des sujets abordés, à leur histoire, aux conditions politiques et éthiques de la pensée critique.The conflicting truths that teachers confront in the classroom come in multiple forms and are acutely topical: denials of the facts, conspiracy theories, extremisms, etc. They relate to contemporary epistemological, political and ethnical problems. Alongside the crisis of Western rationality and identity-related demands, there is now the massive exposure of young minds to the most obscurantist propagandas. This introduction presents the dossier, whose articles attest to these concerns, shine light on them, analyse classroom situations and suggest directions for teaching. In order to support students to use their faculties of reason, attention must be paid to the emotional dimension of the subjects tackled, to their history, and to the political and ethical conditions of critical thought.Los conflictos de verdades con los que los docentes tienen que enfrentarse en las clases revisten múltiples figuras y son de una actualidad candente: negación de los hechos, teorías del complot, extremismos… Participan de unos problemas epistemológicos, políticos, éticos contemporáneos. A la crisis de la racionalidad occidental, a las reivindicaciones de identidades, se añade la exposición masiva de jóvenes espíritus a las propagandas más oscurantistas. La introducción presenta el dossier, cuyos artículos testimonian de esas preocupaciones, proponen elucidaciones, analizan situaciones en las aulas, sugieren unas orientaciones pedagógicas. Apoyar en los alumnos el uso de su razón no se hace sin prestar atención a la dimensión emocional de los temas tratados, a su historia, a las condiciones políticas y éticas del pensamiento crítico

LOEFFEL Laurence. École, morale laïque et citoyenneté aujourd’hui

La recherche fondamentale se soustrait aux pressions de l’immédiateté, et précisément grâce à cela il arrive qu’elle offre une ressource bienvenue aux démarches concrètes ou au débat commun – mais il est rare qu’elle semble à ce point « tomber à pic ». L’ouvrage coordonné par Laurence Loeffel interrompt le long silence sur la « morale laïque » qui contraste avec les débats passionnés et récurrents sur la laïcité, tout en « relevant le défi » de se demander comment cette notion peut prendre se..

Vergnioux Alain. Théories pédagogiques. Recherches épistémologiques

Le livre d’Alain Vergnioux présente huit chapitres distribués en deux grandes parties. La première présente les « cadres conceptuels » d’une approche épistémologique de la pédagogie et la seconde consiste en des « études de cas », où sont présentées six théories pédagogiques telles qu’elles peuvent être comprises à l’aide de ces cadres, dont elles valident alors la teneur et l’usage. Le titre double se comprend donc, ainsi que la construction du livre, dans la mesure où la conclusion reprend ..

Postface: l'identite d'un metier

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Vergnioux Alain. Théories pédagogiques. Recherches épistémologiques

Le livre d’Alain Vergnioux présente huit chapitres distribués en deux grandes parties. La première présente les « cadres conceptuels » d’une approche épistémologique de la pédagogie et la seconde consiste en des « études de cas », où sont présentées six théories pédagogiques telles qu’elles peuvent être comprises à l’aide de ces cadres, dont elles valident alors la teneur et l’usage. Le titre double se comprend donc, ainsi que la construction du livre, dans la mesure où la conclusion reprend ..

Discours et récits sur l’éducation

Cet article explore le thème des récits et discours sur l’éducation dans quatre pays de l’ouest, du sud-ouest, de l’est de l’Asie : la Chine, la Corée, le Pakistan et le Vietnam. Comment une modernité mouvementée y fait-elle récit de son histoire ? Comment s’y conjuguent des justifications et des discours divergents de l’éducation ? Les auteurs montrent comment chaque situation singulière peut être décrite et analysée, pour dégager les traits significatifs d’un questionnement commun et contemporain.This article explores the theme of narratives and discourses on education in four countries in West, South-West and East Asia : China, Korea, Pakistan and Vietnam. How does a turbulent modernity narrativise its history ? How do divergent justifications and discourses on education coalesce within this narrative ? The authors show how each particular situation can be described and analysed to tease out the significant characteristics of a common and contemporary process of questioning.Este artículo explora el tema de los relatos y discursos sobre la educación en cuatro países del oeste, suroeste y este de Asia : China, Corea, Pakistán y Vietnam. ¿Cómo consigue hacer una modernidad tumultuosa el relato de su propia historia ? ¿Cómo se conjugan en estos países unas justificaciones y unos discursos divergentes sobre la educación ? Los autores muestran cómo cada situación singular puede describirse y analizarse para destacar los rasgos significativos de un cuestionamiento común y contemporáneo

Do DOM optical parameters improve the prediction of copper availability in vineyard soils?

International audienceAccumulation of copper (Cu) in soils due to the application of fungicides may be toxic for organisms and hence affect winegrowing sustainability. Soil parameters such as pH and dissolved organic matter (DOM) are known to affect the availability of Cu. In this study, we investigated the contribution of chromophoric and fluorescent DOM properties to the prediction of Cu availability in 18 organic vineyard soils in the Bordeaux winegrowing area (France). The DOM parameters, assessed through absorbance and fluorescence analyses, and proxies for Cu availability (total soluble Cu and free ionic Cu2+) were measured in 0.01 M KCl extracts. Total soluble Cu (CuKCl) varied 23-fold while free ionic Cu2+ varied by a factor of 4600 among the soils. DOC concentrations were similar among the soils, but the samples differed in the quality of DOM as assessed by optical spectroscopy. Multilinear regression models with and without DOM quality parameters were investigated to predict Cu availability. The best model for CuKCl successfully explained 83% of variance and included pH, CuT, and two DOM fluorescence quality indices, the FI fluorescence index, which distinguishes between microbial and higher plant origins, and the HIX humification index. For the prediction of Cu2+, pH alone explained 88% of variance and adding DOM parameters did not improve modelling. The two Cu availability proxies were related to pH. This study confirms the prominent role of pH in Cu availability and underlines the importance of DOM quality to better predict Cu solubilit

Effective Field Theory for Highly Ionized Plasmas

We examine the equilibrium properties of hot, dilute, non-relativistic plasmas. The partition function and density correlation functions of a classical plasma with several species are expressed in terms of a functional integral over electrostatic potential distributions. The leading order, field-theoretic tree approximation automatically includes the effects of Debye screening. Subleading, one-loop corrections are easily evaluated. The two-loop corrections, however, have ultraviolet divergences. These correspond to the short-distance, logarithmic divergence which is encountered in the spatial integral of the Boltzmann exponential when it is expanded to third order in the Coulomb potential. Such divergences do not appear in the underlying quantum theory --- they are rendered finite by quantum fluctuations. We show how such divergences may be removed and the correct finite theory obtained by introducing additional local interactions in the manner of modern effective quantum field theories. We obtain explicit results for density-density correlation functions through two-loop order and thermodynamic quantities through three-loop order. The induced couplings are shown to obey renormalization group equations, and these equations are used to characterize all leading logarithmic contributions in the theory. A linear combination of pressure and energy and number densities is shown to be described by a field-theoretic anomaly. The effective theory allows us to evaluate very easily the algebraic long-distance decay of density correlation functions.Comment: 194 pages, uses elsevier & epsf.sty; final corrections include

Changes over time in organic matter dynamics and copper solubility in a vineyard soil after incorporation of cover crop residues: Insights from a batch experiment

Cover crops (CCs) are increasingly used in viticulture because they benefit the soil and the environment in many ways. This study investigated the extent to which the incorporation of CC residues altered organic matter (OM) and Cu dynamics in a Cu-contaminated vineyard topsoil. A 92-day incubation period was used to monitor changes over time in carbon mineralization, carbon hydrolytic enzyme activity, concentration and optical properties of dissolved organic matter (DOM), and Cu solubility after the addition (or not) of two CC residues, oat or faba bean. The results revealed that adding CCs transitorily increased the concentration of DOM in soil solution, as well as the activity of C hydrolytic enzymes and C mineralization rates. DOM content was approximately two orders of magnitude higher in CC-amended soils than in the control soil on day 0, after which it gradually decreased to reach concentrations similar to those measured in the control soil on day 92. Analyses of DOM optical properties showed that its molecular weight and degree of humification increased over time with a decrease in its concentration. The close relationship between DOM and Cu concentrations in the soil solution suggests that degradation of CCs releases soluble forms of C capable of complexing and solubilizing Cu, and hence that incorporating CC residues can transitorily increase the solubility of Cu in vineyard topsoils. Despite their different C:N ratios, oat and faba bean had almost the same effect on Cu dynamics, implying that C inputs played a prominent role in explaining the interactions between OM and Cu within the timeframe of our experiment. In conclusion, this study enabled recommendations on how to mitigate the risk of Cu ecotoxicity associated with incorporating CCs in Cu-contaminated vineyard soils

The non-Abelian Debye screening length beyond leading order

In quantum electrodynamics, static electric fields are screened at non-zero temperatures by charges in the plasma. The inverse screening length, or Debye mass, may be analyzed in perturbation theory and is of order $eT$ at relativistic temperatures. An analogous situation occurs when non-Abelian gauge theories are studied perturbatively, but the perturbative analysis breaks down when corrections of order $e^2 T$ are considered. At this order, the Debye mass depends on the non-perturbative physics of confinement, and a perturbative ``definition'' of the Debye mass as the pole of a gluon propagator does not even make sense. In this work, we show how the Debye mass can be defined non-perturbatively in a manifestly gauge invariant manner (in vector-like gauge theories with zero chemical potential). In addition, we show how the $O(e^2 T)$ correction could be determined by a fairly simple, three-dimensional, numerical lattice calculation of the perimeter-law behavior of large, adjoint-charge Wilson loops.Comment: 30 pages, revtex format, 9 postscript figures included using epsf.st