Enseignement et apprentissage des mathématiques à l'école primaire dans un contexte bilingue breton-francais

International audienceThis article deals with teaching mathematics in Breton at primary school. We mainly refer to Adler's research (2000, 2001) inviting to consider linguistic plurality not only as a difficulty, but also as a possible resource for mathematics teaching. Her work also invites to focus on available material resources and on the way teachers use them. We study the characteristic features of Breton liable to constitute -or not- the language as a resource for mathematics teaching. Relying on teachers' answers to a questionnaire, we also study the material resources they use and what resources are lacking. We finally discuss our first results and try to suggest a few trails towards taking the linguistic and cultural specificities of the language into account in mathematics teaching.Cet article concerne l'enseignement des mathématiques en breton à l'école primaire. Nous nous référons en particulier aux travaux de Adler (2000, 2001), qui invitent à considérer la pluralité de langues non seulement comme une difficulté, mais comme une ressource possible pour l'enseignement des mathématiques. Ils invitent également à porter attention aux ressources matérielles disponibles, et à leur usage par les professeurs. Nous étudions les caractéristiques de la langue bretonne susceptibles d'amener celle-ci à constituer, ou non, une ressource pour l'enseignement des mathématiques. A partir des réponses de professeurs à un questionnaire, nous étudions les ressources matérielles qu'ils utilisent, et celles qui leur manquent. Enfin, nous discutons nos premiers résultats et essayons de proposer quelques pistes pour une prise en compte de la spécificité de la langue et de la culture bretonne dans l'enseignement des mathématiques en breton

A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Xenopus Tadpoles

Increasing numbers of substances present in the environment are postulated to have endocrine-disrupting effects on vertebrate populations. However, data on disruption of thyroid signaling are fragmentary, particularly at the molecular level. Thyroid hormone (TH; triiodothyronine, T(3)) acts principally by modulating transcription from target genes; thus, thyroid signaling is particularly amenable to analysis with a transcriptional assay. Also, T(3) orchestrates amphibian metamorphosis, thereby providing an exceptional model for identifying thyroid-disrupting chemicals. We combined these two advantages to develop a method for following and quantifying the transcriptional action of T(3) in Xenopus laevis tadpoles. This technology provides a means of assessing thyroid activity at the molecular level in a physiologically relevant situation. Moreover, translucent tadpoles are amenable to “on-line” imaging with fluorescent reporter constructs that facilitate in vivo measurement of transcriptional activity. We adapted transgenesis with TH-responsive elements coupled to either luciferase or green fluorescent protein to follow T(3)-dependent transcription in vivo. To reduce time of exposure and to synchronize responses, we optimized a physiologic pre-treatment protocol that induced competence to respond to T(3) and thus to assess T(3) effects and T(3) disruption within 48 hr. This pretreatment protocol was based on a short (24 hr), weak (10(−12) M) pulse of T(3) that induced TH receptors, facilitating and synchronizing the transcriptional responses. This protocol was successfully applied to somatic and germinal transgenesis with both reporter systems. Finally, we show that the transcriptional assay allows detection of the thyroid-disrupting activity of environmentally relevant concentrations (10(−8) M) of acetochlor, a persistent herbicide

Assessment of Estrogenic Endocrine-Disrupting Chemical Actions in the Brain Using in Vivo Somatic Gene Transfer

Estrogenic endocrine-disrupting chemicals abnormally stimulate vitellogenin gene expression and production in the liver of many male aquatic vertebrates. However, very few studies demonstrate the effects of estrogenic pollutants on brain function. We have used polyethylenimine-mediated in vivo somatic gene transfer to introduce an estrogen response element–thymidine kinase–luciferase (ERE-TK-LUC) construct into the brain. To determine if waterborne estrogenic chemicals modulate gene transcription in the brain, we injected the estrogen-sensitive construct into the brains of Nieuwkoop-Faber stage 54 Xenopus laevis tadpoles. Both ethinylestradiol (EE2; p < 0.002) and bisphenol A (BPA; p < 0.03) increased luciferase activity by 1.9- and 1.5-fold, respectively. In contrast, low physiologic levels of 17β-estradiol had no effect (p > 0.05). The mixed antagonist/agonist tamoxifen was estrogenic in vivo and increased (p < 0.003) luciferase activity in the tadpole brain by 2.3-fold. There have been no previous reports of somatic gene transfer to the fish brain; therefore, it was necessary to optimize injection and transfection conditions for the adult goldfish (Carassius auratus). Following third brain ventricle injection of cytomegalovirus (CMV)-green fluorescent protein or CMV-LUC gene constructs, we established that cells in the telencephalon and optic tectum are transfected. Optimal transfections were achieved with 1 μg DNA complexed with 18 nmol 22 kDa polyethylenimine 4 days after brain injections. Exposure to EE2 increased brain luciferase activity by 2-fold in males (p < 0.05) but not in females. Activation of an ERE-dependent luciferase reporter gene in both tadpole and fish indicates that waterborne estrogens can directly modulate transcription of estrogen-responsive genes in the brain. We provide a method adaptable to aquatic organisms to study the direct regulation of estrogen-responsive genes in vivo

Biomagnification of perfluoroalkyl acids (PFAAs) in the food web of an urban river: assessment of the trophic transfer of targeted and unknown precursors and implications

International audienc

Enseignement et apprentissage des mathématiques à l’école primaire dans un contexte bilingue breton-français

This article deals with teaching mathematics in Breton at primary school. We mainly refer to Adler’s research inviting to consider linguistic plurality not only as a difficulty, but also as a possible resource for mathematics teaching. Her work invites to focus on available material resources and on the way teachers use them. We study the characteristic features of Breton liable to constitute – or not – the language as a resource for mathematics teaching. Relying on teachers’answers to a questionnaire, we also study the material resources they use and what resources are lacking. We finally discuss our first results and try to suggest a few trails towards taking the linguistic and cultural specificities of the language into account in mathematics teaching.Cet article concerne l’enseignement des mathématiques en breton à l’école primaire. Nous nous référons en particulier aux travaux d’Adler, qui invitent à considérer la pluralité de langues non seulement comme une difficulté, mais aussi comme une ressource possible pour l’enseignement des mathématiques. Ils invitent également à porter attention aux ressources matérielles disponibles, et à leur usage par les professeurs. Nous étudions les caractéristiques de la langue bretonne susceptibles d’amener celle-ci à constituer, ou non, une ressource pour l’enseignement des mathématiques. À partir des réponses de professeurs à un questionnaire, nous étudions les ressources matérielles qu’ils utilisent, et celles qui leur manquent. Enfin, nous discutons nos premiers résultats et essayons de proposer quelques pistes pour une prise en compte de la spécificité de la langue et de la culture bretonne dans l’enseignement des mathématiques en breton.Poisard Caroline, Kervran Martine, Le Pipec Erwan, Alliot Stéphane, Gueudet Ghislaine, Hili Hélène, Jeudy-Karakoç Nathalie, Larvol Gwenolé. Enseignement et apprentissage des mathématiques à l’école primaire dans un contexte bilingue breton-français. In: Spirale. Revue de recherches en éducation, n°54, 2014. Langage, apprentissage et enseignement des mathématiques, sous la direction de Thomas Barrier et Anne-Cécile Mathé. pp. 129-150

A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles-1

<p><b>Copyright information:</b></p><p>Taken from "A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles"</p><p>Environmental Health Perspectives 2005;113(11):1588-1593.</p><p>Published online 11 Jul 2005</p><p>PMCID:PMC1310923.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p

A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles-2

<p><b>Copyright information:</b></p><p>Taken from "A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles"</p><p>Environmental Health Perspectives 2005;113(11):1588-1593.</p><p>Published online 11 Jul 2005</p><p>PMCID:PMC1310923.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p

A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles-4

<p><b>Copyright information:</b></p><p>Taken from "A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles"</p><p>Environmental Health Perspectives 2005;113(11):1588-1593.</p><p>Published online 11 Jul 2005</p><p>PMCID:PMC1310923.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p

A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles-0

<p><b>Copyright information:</b></p><p>Taken from "A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Tadpoles"</p><p>Environmental Health Perspectives 2005;113(11):1588-1593.</p><p>Published online 11 Jul 2005</p><p>PMCID:PMC1310923.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p