Quelques logiques de construction d'une séquence d'apprentissage en sciences. L'exemple de la géologie à l'école élémentaire

On invoque souvent un modèle constructiviste d'enseignement, selon une modalité unique et survalorisée. Celle-ci cherche à se démarquer de la tradition transmissive, comme de l'héritage non directif. Il serait utile de disposer d'alternatives et de variantes didactiques multiples, également justifiables selon les objectifs du moment. L'article propose de distinguer quatre modes de commande pour une séquence d'enseignement scientifique. Leur emploi raisonné peut être combiné dans la pratique, contribuant à limiter la monotonie des situations didactiques. Il développe et discute des exemples, empruntés à une recherche récente, relative à l'enseignement de la géologie à l'école élémentair

L'émergence de la didactique de la biologie, un itinéraire

Depuis une quinzaine d'années, la didactique de la biologie se développe, et tente de se constituer comme une discipline autonome, générant ses concepts spécifiques. L'équipe de recherche de l'INRP est l'une des plus anciennes dans ce domaine, et l'auteur, actuellement responsable de cette équipe, décrit ici l'itinéraire et les évolutions intellectuelles qui ont conduit à l'émergence d'une didactique spécialisée, à partir d'une " pédagogie des sciences ". Ce texte tente d'identifier les ruptures théoriques et les problèmes nouveaux auxquels s'affronte cette discipline en développement. Il est issu d'une note de synthèse, rédigée pour la soutenance d'une Thèse sur travaux, à l'Université Lyon II, en 198

Approche didactique de quelques aspects du concept d'écosystème. Introduction

Trois articles de ce numéro d'Aster, relatifs aux notions de Milieu, de Population et de Relations alimentaires prolongent la publication d'un précédent rapport de recherche. Cette introduction développe la problématique d'ensemble qui a orienté la rédaction de ces articles, en insistant particulièrement sur les deux concepts didactiques d'objectif-obstacle et de niveau/registre de formulatio

Milieu

Le concept de Milieu présente la particularité d'être présent de façon implicite dans de nombreux textes scientifiques sans faire l'objet d'une définition précise. Lorsqu'il est employé, on constate une large variabilité de significations, que l'on peut souvent rattacher aux stades successifs de son élaboration historique. De même, en situation didactique, l'emploi du mot milieu est beaucoup plus fréquent que les séances de classe où sa construction comme concept est travaillée précisément. Les AA. essaient, après une analyse de contenu de cette notion, de caractériser les obstacles auxquels sa construction se heurte et les étapes possibles de son appropriation. Ils étudient en fonction de cette grille de lecture quelques exemples de séances de classe, et proposent de situer les étapes de construction mises en oeuvr

A novel approach to measure brain-to-brain spatial and temporal alignment during positive empathy

: Empathy is defined as the ability to vicariously experience others' suffering (vicarious pain) or feeling their joy (vicarious reward). While most neuroimaging studies have focused on vicarious pain and describe similar neural responses during the observed and the personal negative affective involvement, only initial evidence has been reported for the neural responses to others' rewards and positive empathy. Here, we propose a novel approach, based on the simultaneous recording of multi-subject EEG signals and exploiting the wavelet coherence decomposition to measure the temporal alignment between ERPs in a dyad of interacting subjects. We used the Third-Party Punishment (TPP) paradigm to elicit the personal and vicarious experiences. During a positive experience, we observed the simultaneous presence in both agents of the Late Positive Potential (LPP), an ERP component related to emotion processing, as well as the existence of an inter-subject ERPs synchronization in the related time window. Moreover, the amplitude of the LPP synchronization was modulated by the presence of a human-agent. Finally, the localized brain circuits subtending the ERP-synchronization correspond to key-regions of personal and vicarious reward. Our findings suggest that the temporal and spatial ERPs alignment might be a novel and direct proxy measure of empathy

Numerical results for the exact spectrum of planar AdS4/CFT3

We compute the anomalous dimension for a short single-trace operator in planar ABJM theory at intermediate coupling. This is done by solving numerically the set of Thermodynamic Bethe Ansatz equations which are expected to describe the exact spectrum of the theory. We implement a truncation method which significantly reduces the number of integral equations to be solved and improves numerical efficiency. Results are obtained for a range of 't Hooft coupling lambda corresponding to $0 \leq h(\lambda) \leq 1$, where h(lambda) is the interpolating function of the AdS4/CFT3 Bethe equations.Comment: v3: corrected Acknowledgements section; v4: minor changes, published version; v5: fixed typos in Eq. (3.9

Kaluza-Klein gauge and minimal integrable extension of OSp(4|6)/(SO(1,3) x U(3)) sigma-model

Basing upon experience from performing double-dimensional reduction of the D=11 supermembrane on AdS_4 x S^7 background to Type IIA superstring on AdS_4 x CP^3 we introduce Kaluza-Klein (partial) kappa-symmetry gauge as a vanishing condition of the contribution to the D=11 supervielbein components tangent to D=10 space-time proportional to the differential of the coordinate parametrizing compact 11-th space-time dimension, that is identified with the supermembrane world-volume compact dimension. For AdS_4 x S^7 supermembrane Kaluza-Klein gauge removes half Grassmann coordinates associated with 8 space-time supersymmetries, broken by the AdS_4 x CP^3 superbackground, by imposing D=3 (anti-)Majorana condition on them. The consideration relies on the realization of osp(4|8) isometry superalgebra of the AdS_4 x S^7 superbackground as D=3 N=8 superconformal algebra. Requiring further vanishing of the D=10 dilaton leaves in the sector of broken supersymmetries just two Grassmann coordinates organized into D=3 (anti-)Majorana spinor that defines minimal SL(2,R)-covariant extension of the OSp(4|6)/(SO(1,3)x U(3)) sigma-model. Among 4 possibilities of such a minimal extension we consider in detail one, that corresponds to picking out D=3 Majorana coordinate related to broken Poincare supersymmetry, and show that the AdS_4 x CP^3 superstring equations of motion in this partial kappa-symmetry gauge are integrable. Also the relation between the OSp(4|6)/(SO(1,3) x U(3)) sigma-model and the AdS_4 x CP^3 superstring is revisited.Comment: LaTeX, 22 pages; v2: minor improvements in the text, typos corrected, references adde

Isolamento e caracterização de marcadores microssatélites em guaranazeiro (Paullinia cupana var. sorbilis).

O objetivo deste trabalho foi desenvolver marcadores microssatélites para serem usados na caracterização da diversidade genética contida no Banco de Germoplasma de guaranazeiro da Embrapa

Strings in AdS_4 x CP^3: finite size spectrum vs. Bethe Ansatz

We compute the first curvature corrections to the spectrum of light-cone gauge type IIA string theory that arise in the expansion of $AdS_4\times \mathbb{CP}^3$ about a plane-wave limit. The resulting spectrum is shown to match precisely, both in magnitude and degeneration that of the corresponding solutions of the all-loop Gromov--Vieira Bethe Ansatz. The one-loop dispersion relation correction is calculated for all the single oscillator states of the theory, with the level matching condition lifted. It is shown to have all logarithmic divergences cancelled and to leave only a finite exponentially suppressed contribution, as shown earlier for light bosons. We argue that there is no ambiguity in the choice of the regularization for the self-energy sum, since the regularization applied is the only one preserving unitarity. Interaction matrices in the full degenerate two-oscillator sector are calculated and the spectrum of all two light magnon oscillators is completely determined. The same finite-size corrections, at the order 1/J, where $J$ is the length of the chain, in the two-magnon sector are calculated from the all loop Bethe Ansatz. The corrections obtained by the two completely different methods coincide up to the fourth order in $\lambda' =\lambda/J^2$. We conjecture that the equivalence extends to all orders in $\lambda$ and to higher orders in 1/J.Comment: 32 pages. Published version; journal reference adde

Classical integrability and quantum aspects of the AdS(3) x S(3) x S(3) x S(1) superstring

In this paper we continue the investigation of aspects of integrability of the type IIA AdS(3) x S(3) x S(3) x S(1) and AdS(3) x S(3) x T(4) superstrings. By constructing a one parameter family of flat connections we prove that the Green-Schwarz string is classically integrable, at least to quadratic order in fermions, without fixing the kappa-symmetry. We then compare the quantum dispersion relation, fixed by integrability up to an unknown interpolating function h(lambda), to explicit one-loop calculations on the string worldsheet. For AdS(3) x S(3) x S(3) x S(1) the spectrum contains heavy, as well as light and massless modes, and we find that the one-loop contribution differs depending on how we treat these modes showing that similar regularization ambiguities as appeared in AdS(4)/CFT(3) occur also here.Comment: 29 pages; v2: updated references and acknowledgmen