Quelles fonctions de deux systèmes didactiques auxiliaires destinés à des élèves en difficulté lors de la résolution d'une situation-problème mathématique ?

Solving mathematical problems is a major challenge for students with difficulties. In this article, we examine an assistance system tested by an elementary school teacher during a two-year collaborative research. This system consists of setting up two auxiliary educational systems (AES), in the form of a work session with the students presumed by the teacher to be having trouble, that is held prior to the solving of the problem with the whole class and another work session held after the solving of the problem. Within the AES, the teacher explains the problem to the students, and discusses concepts with the student regarded as prerequisites by the teacher. In the AES held after the solving of the problem, the teacher revisits the institutionalisation made with the whole class. In this article, we analyze the potential functions of our assistance system through the triple dimensions identified by Sensevy et al. (2000): Chronogenesis, mesogenesis and topogenesis.Résoudre des situations-problèmes mathématiques constitue un défi important pour les élèves en difficulté. Dans cet article, nous analysons un dispositif d'aide mis en œuvre par une enseignante dans le cadre d'une recherche collaborative. Ce dispositif consiste en la mise sur pied de deux systèmes didactiques auxiliaires (SDA). Le premier SDA prend la forme d'une rencontre de travail avec les élèves présumés en difficulté qui a lieu avant la résolution de la situation-problème en classe. Durant ce SDA, l'enseignante présente la consigne et discute de concepts qu'elle considère être des prérequis pour travailler sur la situation-problème. Au cours du SDA réalisé après la résolution de la situation-problème en classe, l'enseignante revisite l'institutionnalisation avec les élèves en difficulté. Dans cet article, nous analysons les fonctions de ces SDA à travers le triplet des genèses de Sensevy et al. (2000): chronogenèse, mésogenèse et topogenèse

Expression of C-terminal deleted p53 isoforms in neuroblastoma

The tumor suppressor gene, p53, is rarely mutated in neuroblastomas (NB) at the time of diagnosis, but its dysfunction could result from a nonfunctional conformation or cytoplasmic sequestration of the wild-type p53 protein. However, p53 mutation, when it occurs, is found in NB tumors with drug resistance acquired over the course of chemotherapy. As yet, no study has been devoted to the function of the specific p53 mutants identified in NB cells. This study includes characterization and functional analysis of p53 expressed in eight cell lines: three wild-type cell lines and five cell lines harboring mutations. We identified two transcription-inactive p53 variants truncated in the C-terminus, one of which corresponded to the p53β isoform recently identified in normal tissue by Bourdon et al. [J. C. Bourdon, K. Fernandes, F. Murray-Zmijewski, G. Liu, A. Diot, D. P. Xirodimas, M. K. Saville and D. P. Lane (2005) Genes Dev., 19, 2122–2137]. Our results show, for the first time, that the p53β isoform is the only p53 species to be endogenously expressed in the human NB cell line SK-N-AS, suggesting that the C-terminus truncated p53 isoforms may play an important role in NB tumor development

Différenciation des cellules épithéliales respiratoires chez les mammifères (modulation par les retinoides et expression des protéines p63 et p73)

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Interactivité entre p73 et p53 dans les cancers : un modèle, le neuroblastome

L’homologie de structure et d’organisation génique existant entre p53 et ses deux homologues, p73 et p63, suggère des fonctions biologiques similaires. Néanmoins des différences notables existent entre les membres de la famille p53. Ainsi, p53 est fréquemment muté dans les cancers humains, contrairement à p73 et p63. De plus, à l’opposé de p53 dont le transcrit majoritaire couvre tous les exons du gène, p73 et p63 codent pour deux types d’isoformes aux effets biologiques opposés : les unes, contenant un domaine de transactivation (TAD), ont des propriétés de protéine suppresseur de tumeur, tandis que les autres, dépourvues de TAD, possèdent des propriétés oncogéniques. Par ailleurs, si p53 répond aux stimulus génotoxiques, ses homologues participent au développement et à la différenciation tissulaires : tissu neuronal pour p73, tissu épithélial pour p63. Mais les trois membres de la famille p53 peuvent coopérer étroitement lors de la réponse cellulaire consécutive à un dommage génotoxique. Les tumeurs neuroblastiques, qui reproduisent les différents stades de différenciation des cellules du système nerveux sympathique, constituent un modèle de choix pour étudier les relations entre p53 et p73, ainsi que la régulation de leur expression

Formin-2 is required for spindle migration and for the late steps of cytokinesis in mouse oocytes

International audienc

Des carrières variées

Torner Véronique, Wang Cher, Auzac Evelyne d', Skoric Karine, Carton Stéphanie, P. Marie, Million-Lajoinie Marie-Madeleine. Des carrières variées. In: Diplômées, n°249, 2014. Les femmes dans le numérique : un défi à relever. pp. 74-78

Thrombosis and antiphospholipid antibody syndrome during acute Q fever

International audienceQ fever is a neglected and potentially fatal disease. During acute Q fever, antiphospholipid antibodies are very prevalent and have been associated with fever, thrombocytopenia, acquired heart valve disease, and progression to chronic endocarditis. However, thrombosis, the main clinical criterion of the 2006 updated classification of the antiphospholipid syndrome, has not been assessed in this context. To test whether thrombosis is associated with antiphospholipid antibodies and whether the criteria for antiphospholipid syndrome can be met in patients with acute Q fever, we conducted a cross-sectional study at the French National Referral Center for Q fever.Patients included were diagnosed with acute Q fever in our Center between January 2007 and December 2015. Each patient's history and clinical characteristics were recorded with a standardized questionnaire. Predictive factors associated with thrombosis were assessed using a rare events logistic regression model. IgG anticardiolipin antibodies (IgG aCL) assessed by an enzyme-linked immunosorbent assay were tested on the Q fever diagnostic serum. A dose-dependent relationship between IgG aCL levels and thrombosis was tested using a receiver operating characteristic (ROC) analysis.Of the 664 patients identified for inclusion in the study, 313 (47.1%) had positive IgG aCL and 13 (1.9%) were diagnosed with thrombosis. Three patients fulfilled the antiphospholipid syndrome criteria. After multiple adjustments, only positive IgG aCL (relative risk, 14.46 [1.85-113.14], P = .011) were independently associated with thrombosis. ROC analysis identified a dose-dependent relationship between IgG aCL levels and occurrence of thrombosis (area under curve, 0.83, 95%CI [0.73-0.93], P < .001).During acute Q fever, antiphospholipid antibodies are associated with thrombosis, thrombocytopenia, and acquired valvular heart disease. Antiphospholipid antibodies should be systematically assessed in acute Q fever patients. Hydroxychloroquine, which has been previously shown to antagonize IgG aCL pathogenic properties, should be tested in acute Q fever patients with anticardiolipin antibodies to prevent antiphospholipid-associated complications.Key Point: In addition to fever, thrombocytopenia and acquired valvular heart disease, antiphospholipid antibodies are associated with thrombosis during acute Q fever

Radiology and artificial intelligence: An opportunity for our specialty

International audienc