999 resultados para Formation d´enseignants en Physique


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ABSTRACT The present study aimed at evaluating the heterotic group formation in guava based on quantitative descriptors and using artificial neural network (ANN). For such, we evaluated eight quantitative descriptors. Large genetic variability was found for the eight quantitative traits in the 138 genotypes of guava. The artificial neural network technique determined that the optimal number of groups was three. The grouping consistency was determined by linear discriminant analysis, which obtained classification percentage of the groups, with a value of 86 %. It was concluded that the artificial neural network method is effective to detect genetic divergence and heterotic group formation.

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A drinking experiment with participants suffering from Gilbert's syndrome was performed to study the possible influence of this glucuronidation disorder on the formation of ethyl glucuronide (EtG). Gilbert's syndrome is a rather common and, in most cases, asymptomatic congenital metabolic aberration with a prevalence of about 5 %. It is characterized by a reduction of the enzyme activity of the uridine diphosphate glucuronosyltransferase (UGT) isoform 1A1 up to 80 %. One of the glucuronidation products is EtG, which is formed in the organism following exposure to ethanol. EtG is used as a short-term marker for ethyl alcohol consumption to prove abstinence in various settings. After 2 days of abstinence from ethanol and giving a void urine sample, 30 study participants drank 0.1 L of sparkling wine (9 g ethanol). 3, 6, 12, and 24 h after drinking, urine samples were collected. 3 hours after drinking, an additional blood sample was taken, in which liver enzyme activities, ethanol, hematological parameters, and bilirubin were measured. EtG and ethyl sulfate (EtS), another short-term marker of ethanol consumption, were determined in the urine samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS); creatinine was measured photometrically. In all participants, EtG and EtS were detected in concentrations showing a wide range (EtG: 3 h sample 0.5-18.43 mg/L and 6 h sample 0.67-13.8 mg/L; EtS: 3 h sample 0.87-6.87 mg/L and 6 h sample 0.29-4.48 mg/L). No evidence of impaired EtG formation was found. Thus, EtG seems to be a suitable marker for ethanol consumption even in individuals with Gilbert's syndrome.

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Cancer stem cells are cancer cells characterized by stem cell properties and represent a small population of tumor cells that drives tumor development, progression, metastasis and drug resistance. To date, the molecular mechanisms that generate and regulate cancer stem cells are not well defined. BORIS (Brother of Regulator of Imprinted Sites) or CTCFL (CTCF-like) is a DNA-binding protein that is expressed in normal tissues only in germ cells and is re-activated in tumors. Recent evidences have highlighted the correlation of BORIS/CTCFL expression with poor overall survival of different cancer patients. We have previously shown an association of BORIS-expressing cells with stemness gene expression in embryonic cancer cells. Here, we studied the role of BORIS in epithelial tumor cells. Using BORIS-molecular beacon that was already validated, we were able to show the presence of BORIS mRNA in cancer stem cell-enriched populations (side population and spheres) of cervical, colon and breast tumor cells. BORIS silencing studies showed a decrease of sphere formation capacity in breast and colon tumor cells. Importantly, BORIS-silencing led to down-regulation of hTERT, stem cell (NANOG, OCT4, SOX2 and BMI1) and cancer stem cell markers (ABCG2, CD44 and ALDH1) genes. Conversely, BORIS-induction led to up-regulation of the same genes. These phenotypes were observed in cervical, colon and invasive breast tumor cells. However, a completely different behavior was observed in the non-invasive breast tumor cells (MCF7). Indeed, these cells acquired an epithelial mesenchymal transition phenotype after BORIS silencing. Our results demonstrate that BORIS is associated with cancer stem cell-enriched populations of several epithelial tumor cells and the different phenotypes depend on the origin of tumor cells.

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Les membres de la Génération Sandwich (GS) jouent un rôle pivot dans la société : tout en ayant un emploi, ils s'occupent de leurs enfants ou petits-enfants et offrent de l'aide à leurs parents ou beaux-parents (P/BP) fragilisés par leur vieillissement. Les charges de travail coexistantes générées par ces activités représentent pour leur santé un risque potentiel qui pourrait augmenter. Les connaissances sur la GS et sa santé perçue sont cependant insuffisantes pour que les infirmières de santé au travail développent des interventions préventives basées sur des preuves. La majorité des recherches existantes ont considéré la coexistence des charges comme a priori pathogénique. La plupart des études n'ont examiné l'association que d'une ou de deux de ces trois activités avec la santé. Très peu ont utilisé un cadre théorique infirmier. La présente thèse visait à développer les connaissances sur les membres de la GS et leur santé perçue. Aussi, nous avons adopté une des stratégies existantes pour développer des théories en science infirmière - donc pour développer des connaissances infirmières pour intervenir - décrites par Meleis (2012) : la stratégie « de la Théorie à la Recherche à la Théorie ». Premièrement, un cadre de référence infirmier salutogénique a été construit. Il s'est basé sur le modèle de soins Neuman Systems Model, des concepts issus de la théorie Déséquilibre entre Effort et Récompense de Siegrist et d'une recension intégrative des écrits. Il relie les charges de la GS avec la santé perçue et suggère l'existence de facteurs protégeant la santé. Deuxièmement, un dispositif de recherche descriptif corrélationnel exploratoire a été mis en place pour confronter les deux propositions relationnelles du cadre théorique au monde empirique. Des données ont été récoltées au moyen d'un questionnaire électronique rempli par 826 employés d'une administration publique (âge 45-65 ans). Après examen, 23.5% de l'échantillon appartenait à la GS. La probabilité d'appartenir à la GS augmentait avec l'avancement en âge des P/BP, la co-résidence et la présence d'un enfant dans le ménage ; cependant le sexe n'influençait pas cette probabilité. Les analyses n'ont révélé aucune relation entre la charge totale et la santé physique ou mentale des femmes. Néanmoins, il y avait une relation négative entre cette charge et la santé physique des hommes et une relation négative proche du seuil de significativité, sans toutefois l'atteindre, entre cette charge et leur santé mentale. La nature de ces deux dernières relations était principalement le fait de la charge de travail domestique et familiale. Cinq facteurs identifiés théoriquement ont effectivement protégé la santé de la GS de leurs charges coexistantes : l'absence de sur-engagement dans l'activité professionnelle et une grande latitude décisionnelle dans l'aide aux P/BP ont protégé la santé mentale des femmes ; une grande latitude décisionnelle dans l'activité domestique et familiale a protégé la santé mentale des hommes ; l'absence de sur-engagement dans l'aide aux P/BP et des relations de bonne qualité dans l'activité professionnelle ont protégé la santé physique des hommes. S'appuyant sur ces facteur protecteurs de la santé, cette thèse a proposé des pistes afin de développer des interventions pour la prévention primaire en santé au travail qui soient soucieuses de faire évoluer favorablement les inégalités de genre (gender-transformative). Elles ne concernent pas seulement les membres de la GS et les P/BP, mais aussi les employeurs. Troisièmement, comme les deux propositions relationnelles ont plutôt bien supporté la confrontation avec le monde empirique, cette thèse offre des suggestions pour poursuivre le développement de son cadre théorique et tendre vers la création d'une théorie de moyenne portée en science infirmière.

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En aquest treball s’ha estudiat el comportament de compostos antimalàrics com els fàrmacs i els polímers en diferents situacions. Una de les barreres que ha estat identificada com a principal obstacle per a una millora de l’eficàcia dels compostos antimalàrics, és la limitació en la quantitat de fàrmac que pot ser encapsulada dins un liposoma, i que depèn de la seva solubilitat en medi aquós. Amb la inspiració de la descripció d’un nou tipus de nanocàpsules amb aplicacions oncològiques capaces d’encapsular grans quantitats de fàrmacs (protocells, Ashley et al., 2011). Els constructes formats per liposomes amb un nucli d’òxid de silici altament porós capaç de contenir el fàrmac, s’anomenen “protocells”, que en comparació als liposomes, tenen una major selectivitat i estabilitat, i permeten alliberar altes concentracions de droga directament al citosol de les cèl·lules cancerígenes. Aquest estudi es basa en la fabricació d’aquests nous nanovectors que continguin fàrmacs antimalàrics i té com a objectiu futur dirigir-los a eritròcits infectats per malària (pRBCs). Una altra part del treball és l’estudi de la distribució del polímer ISA-FITC en Anopheles atroparvus. Sabent que els polímers han estat utilitzats com a transportadors antimalàrics, es va pensar en l’opció d’eliminar el paràsit a dins del mateix mosquit, com una alternativa a tots el estudis realitzats fins ara centrats en les etapes d’infecció de l’hoste. Per aquest motiu es va idear l’experiment pensant en aquest polímer amb la intenció final de veure la seva localització en un mosquit Anopheles lliure del paràsit. OBJECTIUS: Determinació de la capacitat encapsuladora de tres tipus de nanopartícules, fabricades amb el mateix material però amb característiques de mida i càrrega diferents, incubant-les amb cinc fàrmacs antimalàrics. El blau de metilè, la primaquina, la cloroquina, la quinina i la curcumina, cadascun d’ells amb característiques de pH, solubilitat i estructura diferents. Alguns d’ells són fàrmacs que no s’han emprat en altres estudis degut a la seva toxicitat o elevada inespecificitat (la qual es pretén reduir un cop encapsulats en protocells). Construcció de “protocells” un cop determinada la millor nanopartícula encapsuladora i fàrmac candidat i determinació de la concentració de fàrmac que podien contenir, i el ritme d’alliberament d’aquest en PBS (simulant les condicions fisiològiques dels pRBCs). Estudi de la localització del polímer antimalàric ISA-FITC en l’anatomia del mosquit Anopheles Atroparvus. PROCEDIMENTS: Mètodes espectrofotomètrics Microscopia Cryo-electrònica de transmissió Microscopia confocal de fluorescència

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Le management des risques dans les institutions psychiatriques représente aujourd'hui un challenge majeur pour les cliniciens, les administrateurs et les décideurs politiques. Il pose la question de la formation des équipes au management de la violence et de l'évaluation des patients dans la clinique quotidienne. Cet article fait le lien entre une étude, menée sur un an dans une institution psychiatrique et un modèle de management des risques, le modèle cindynique. Les résultats doivent interroger sur les représentations du phénomène de violence par les différents acteurs, l'appropriation par les équipes d'outils d'évaluation de la dangerosité et sur la communication dans l'équipe pluridisciplinaire et avec le patient.

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Identity metamorphoses in a context of mobility This study has its roots in the current upsurge in student mobility and in the scientific debates about the concepts of identity and intercultural communication. Based on a corpus of interviews with French Erasmus students in Finland, the study blends in theories of postmodern identity, intercultural hermeneutics and discourse analysis to examine how the students construct themselves and diverse ‘othernesses’ (included theirs) when they talk about their experiences. The use of the French pronoun on, pronoun switches, and virtual voices (ex: I said to myself...) allowed to pinpoint the students’ unstable identity metamorphoses in their discourses: integration of liquid and solid selves, infidelity in identification with the French but also with Erasmus ‘tribes’, and games of identity. Though the exchange experience appears as interesting for the students, the results show that many and varied misconceptions about identity, culture, intercultural communication, language use, and strangeness lead the students to evaluate their experiences negatively. The implication of the study is that students should be prepared for their time abroad, not so much in terms of ‘grammars of culture’ (e.g. ‘Finns behave in such and such ways’, ‘the French are...’), but through the development of competences to analyse the identity metamorphoses that take place in intercultural encounters and prevent people from meeting each other as diverse individuals. This could make study abroad one of the best training periods for postmodernity and globalization.

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Bone engineering is a rapidly developing area of reconstructive medicine where bone inducing factors and/or cells are combined with a scaffold material to regenerate the structure and function of the original tissue. The aim of this study was to compare the suitability of different macroporous scaffold types for bone engineering applications. The two scaffold categories studied were a) the mechanically strong and stable titanium fiber meshes and b) the elastic and biodegradable porous polymers. Furthermore, bioactive modifications were applied to these basic scaffold types, and their effect on the osteogenic responses was evaluated in cell culture and ectopic bone formation studies. The osteogenic phenotype of cultured cell-scaffold constructs was heightened with a sol-gel derived titania coating, but not with a mixed titania-silica coating. The latter coating also resulted in delayed ectopic bone formation in bone marrow stromal cell seeded scaffolds. However, the better bone contact in early implantation times and more even bone tissue distribution at later times indicated enhanced osteoconductivity of both the coated scaffold types. Overall, the most promising bone engineering results were obtained with titania coated fiber meshes. Elastic and biodegradable poly(ε-caprolactone/D,L-lactide) based scaffolds were also developed in this study. The degradation rates of the scaffolds in vitro were governed by the hydrophilicity of the polymer matrix, and the porous architecture was controlled by the amount and type of porogen used. A continuous phase macroporosity was obtained using a novel CaCl2 • 6H2O porogen. Dynamic culture conditions increased cell invasion, but decreased cell numbers and osteogenicity, within the scaffolds. Osteogenic differentiation in static cultures and ectopic bone formation in cell seeded scaffolds were enhanced in composites, with 30 wt-% of bioactive glass filler.

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The purpose of this study was to increase the understanding of the role and nature of trust in asymmetric technology partnership formation. In the knowledge-based "learning race" knowledge is considered as a primary source for competitive advantage. In the emerging ICT sector the high pace of technological change, the convergence of technologies and industries as well as the increasing complexity and uncertainty have forced even the largest players to seek cooperation for complementary knowledge and capabilities. Small technology firms need the complementary resources and legitimacy of the large firms to grow and compete in the global market place. Most of the earlier research indicates, however, that partnerships with asymmetric size, managerial resources and cultures have failed. A basic assumption supported by earlier research was that trust is a critical factor in asymmetric technology partnership formation. Asymmetric technology partnership formation is a dynamic and multi-dimensional process, and consequently a holistic research approach was selected. Research issue was approached from different levels: the individual decision-maker, the firm and the relationship between the parties. Also the impact of the dynamic environment and technology content was analyzed. A multitheoretical approach and a qualitative research method with in-depth interviews in five large ICT companies and eight small ICT companies enabled a holistic and rich view of the research issue. Study contributes on the scarce understanding on the nature and evolution of trust in asymmetric technology partnership formation. It sheds also light on the specific nature of asymmetric technology partnerships. The partnerships were found to be tentative and the diverse strategic intent of small and large technology firms appeared as a major challenge. The role of the boundary spanner was highlighted as a possibility to match the incompatible organizational cultures. A shared vision was found to be a pre-condition for individual-based fast trust leading to intuitive decision-making and experimentation. The relationships were tentative and they were continuously re-evaluated through the key actors' sense making of the technology content, asymmetry and the dynamic environment. A multi-dimensional conceptualization for trust was created and propositions on the role and nature of trust for further research are given. The purpose of this study was to increase the understanding of the role and nature of trust in asymmetric technology partnership formation. In the knowledge-based "learning race" knowledge is considered as a primary source for competitive advantage. In the emerging ICT sector the high pace of technological change, the convergence of technologies and industries as well as the increasing complexity and uncertainty have forced even the largest players to seek cooperation for complementary knowledge and capabilities. Small technology firms need the complementary resources and legitimacy of the large firms to grow and compete in the global market place. Most of the earlier research indicates, however, that partnerships with asymmetric size, managerial resources and cultures have failed. A basic assumption supported by earlier research was that trust is a critical factor in asymmetric technology partnership formation. Asymmetric technology partnership formation is a dynamic and multi-dimensional process, and consequently a holistic research approach was selected. Research issue was approached from different levels: the individual decision-maker, the firm and the relationship between the parties. Also the impact of the dynamic environment and technology content was analyzed. A multitheoretical approach and a qualitative research method with in-depth interviews in five large ICT companies and eight small ICT companies enabled a holistic and rich view of the research issue. Study contributes on the scarce understanding on the nature and evolution of trust in asymmetric technology partnership formation. It sheds also light on the specific nature of asymmetric technology partnerships. The partnerships were found to be tentative and the diverse strategic intent of small and large technology firms appeared as a major challenge. The role of the boundary spanner was highlighted as a possibility to match the incompatible organizational cultures. A shared vision was found to be a pre-condition for individual-based fast trust leading to intuitive decision-making and experimentation. The relationships were tentative and they were continuously re-evaluated through the key actors' sense making of the technology content, asymmetry and the dynamic environment. A multi-dimensional conceptualization for trust was created and propositions on the role and nature of trust for further research are given.

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The cuticle is an essential diffusion barrier on aerial surfaces of land plants whose structural component is the polyester cutin. The PERMEABLE CUTICLE1/ABCG32 (PEC1) transporter is involved in plant cuticle formation in Arabidopsis. The gpat6 pec1 and gpat4 gapt8 pec1 double and triple mutants are characterized. Their PEC1-specific contributions to aliphatic cutin composition and cuticle formation during plant development are revealed by gas chromatography/mass spectrometry and Fourier-transform infrared spectroscopy. The composition of cutin changes during rosette leaf expansion in Arabidopsis. C16:0 monomers are in higher abundance in expanding than in fully expanded leaves. The atypical cutin monomer C18:2 dicarboxylic acid is more prominent in fully expanded leaves. Findings point to differences in the regulation of several pathways of cutin precursor synthesis. PEC1 plays an essential role during expansion of the rosette leaf cuticle. The reduction of C16 monomers in the pec1 mutant during leaf expansion is unlikely to cause permeability of the leaf cuticle because the gpat6 mutant with even fewer C16:0 monomers forms a functional rosette leaf cuticle at all stages of development. PEC1/ABCG32 transport activity affects cutin composition and cuticle structure in a specific and non-redundant fashion.

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Réunissant quelques-uns des meilleurs experts français sur la question, le projet de cet ouvrage est de dresser un bilan des principales orientations historiographiques de l'histoire du sport. Cette réflexion complète la table ronde organisée lors du congrès du comité français des sciences historiques (Reims 2012). Elle s'interroge sur la spécificité d'un champ qui s'est développé en marge de l'Histoire en abordant un objet - le sport - qui traverse les cultures et les périodes, et entretient avec les registres politiques, sociaux, économiques, médiatiques, ou scientifiques des liens originaux. Appuyée sur des comparaisons européennes et nordaméricaines, elle suggère aussi des perspectives et de nouvelles pistes à investiguer. Cet ouvrage constitue une base de données précieuse pour les étudiants, doctorants, enseignants, chercheurs, archivistes et conservateurs et, plus largement, tout public averti et désireux de comprendre comment l'histoire a, jusqu'ici, questionné le phénomène sportif. Le lecteur y puisera des éléments conceptuels et des points d'appui historiographiques essentiels. Les grands débats du moment s'y reflètent : sport dans l'Antiquité, histoire de l'éducation physique, histoire économique du sport, histoire des techniques, des médias, du genre, ou encore histoire du sport en milieu colonial.