Les représentations sociales du collège et de la réussite chez les garçons en sciences humaines au collégial

"La présente recherche a été subventionnée par le Ministère de l'éducation dans le cadre du Programme d'aide à la recherche sur l'enseignement et l'apprentissage (PAREA)"Titre de l'écran-titre (visionné le 7 août 2006)Également disponible en version papierBibliogr

Les représentations sociales du collège et de la réussite chez les garçons en sciences humaines au collégial

"La présente recherche a été subventionnée par le Ministère de l'éducation dans le cadre du Programme d'aide à la recherche sur l'enseignement et l'apprentissage (PAREA)"Titre de l'écran-titre (visionné le 7 août 2006)Également disponible en version papierBibliogr

X-ray structural analysis of compensating mutations at the barnase-barstar interface

AbstractThe crystal structure of the barstar mutants (Y29P) and (Y29D, Y30W) as well as that of the complexes of barstar(Y29P) with wild-type barnase and barnase(H102K) have been determined. These barstar mutants compensate for the dramatic loss of barnase-barstar interaction energy caused by a single mutation of the barnase active site His-102 to a lysine. The latter introduces an uncompensated charge in the pocket at the surface of barstar where Lys-102 is located. The analysis of the structures suggests a mechanism for this compensation based on the solvation of the charge of Lys-102. Additional compensation occurs through the formation of a hydrogen bond

Effects of Oil and Chemically Treated Oil on Nearshore Under-Ice Meiofauna Studied in Situ

Meiofauna collected during May 1982 in the soft bottom layer of nearshore landfast ice at Cape Hatt, northern Baffin Island, were dominated by cyclopoid copepods, harpacticoid copepods, nematodes and polychaete larvae (73.5, 15.4, 6.3 and 3.5% of total numbers respectively). Also included were rotifers, gastropod veligers and calanoid copepod nauplii; calanoid nauplii were probably present in the near-ice water and not on or in the ice. Average abundance of all ice meiofauna was 54,000 individuals/sq m. Densities of all meiofauna groups were spatially variable, but only nematodes and cyclopoid copepods showed evidence of progressive temporal change between 18 May and 2 June. Undisturbed, enclosed areas of the under-ice surface were treated with oil on 23-24 May. Dispersed oil (Venezuela Lagomedio + Corexit 9527, BP CTD or BP 1100 WD) was in contact with the ice for 5 hours, whereas untreated oil and solidified oil (BP treatment) remained in the enclosures for the duration of the study (12 days post-treatment). Sampling was carried out in areas where oil contacted the ice and moved away or in areas near oil that remained in contact with the under-ice surface. Five hours after treatment, oil concentrations in the water within the enclosures were similar (0.15-0.28 ppm) in untreated oil, solidified oil and control enclosures. In contrast, dispersed oil oil concentrations were 5.8-36.5 ppm. Densities of all copepods and polychaetes decreased dramatically in each dispersed oil enclosure by the second post-spill day, and slight density increases were evident by the tenth post-spill day. Harpacticoid copepods apparently were more sensitive to dispersed oil than were cyclopoid copepods. Densities of nematodes and cyclopoid copepod nauplii were not affected by dispersed oil. Densities of nematodes, polychaetes and all copepods were not affected by untreated or solidified oil, but there was some evidence of a stimulatory effect of those treatments on some copepod groups and life stages.Key words: Arctic, ice meiofauna, ice copepods, ice polychaetes, ice nematodes, oil effects, dispersed oil effects, solidified oil effects, Baffin IslandMots clés: arctique, méiofaune glaciaire, copépodes glaciaires, polychètes glaciaires, nématodes glaciaires, effets dus au pétrole, effets dus au pétrole dispersé, effets dus au pétrole solidifié, île Baffi

Perception des cours de philosophie et de littérature chez les élèves de Soins infirmiers : influence de leurs enseignants.

L'objectif général de notre recherche était donc de déterminer l'influence des enseignantes et enseignants de Soins infirmiers sur la perception des élèves à l'égard des cours de philosophie et de littérature. Nous avons utilisé le concept de représentation sociale qui relève de la psychologie sociale, tout indiquée pour étudier l'interaction entre les enseignantes et les enseignants et les élèves. Plus spécifiquement, nous voulions répondre aux trois objectifs suivants : décrire les représentations sociales des élèves de Soins infirmiers concernant les cours de philosophie et de littérature; identifier les propos tenus par les enseignantes et enseignants de Soins infirmiers à leurs élèves au sujet des cours de philosophie et de littérature, tels que ceux-ci les rapportent; déterminer la présence de liens entre les propos tels qu'ils sont rapportés et les représentations sociales des élèves à l'égard de ces cours

The promises of gravitational-wave astronomy

No abstract available

Eukaryotic Cell Permeabilisation to Identify New Putative Chlamydial Type III Secretion System Effectors Secreted within Host Cell Cytoplasm.

Chlamydia trachomatis and Waddlia chondrophila are strict intracellular bacteria belonging to the Chlamydiales order. C. trachomatis is the most frequent bacterial cause of genital and ocular infections whereas W. chondrophila is an opportunistic pathogen associated with adverse pregnancy outcomes and respiratory infections. Being strictly intracellular, these bacteria are engaged in a complex interplay with their hosts to modulate their environment and create optimal conditions for completing their life cycle. For this purpose, they possess several secretion pathways and, in particular, a Type III Secretion System (T3SS) devoted to the delivery of effector proteins in the host cell cytosol. Identifying these effectors is a crucial step in understanding the molecular basis of bacterial pathogenesis. Following incubation of infected cells with perfringolysin O, a pore-forming toxin that binds cholesterol present in plasma membranes, we analysed by mass spectrometry the protein content of the host cell cytoplasm. We identified 13 putative effectors secreted by C. trachomatis and 19 secreted by W. chondrophila. Using Y. enterocolitica as a heterologous expression and secretion system, we confirmed that four of these identified proteins are secreted by the T3SS. Two W. chondrophila T3SS effectors (hypothetical proteins Wcw_0499 and Wcw_1706) were further characterised and demonstrated to be early/mid-cycle effectors. In addition, Wcw_1706 is associated with a tetratricopeptide domain-containing protein homologous to C. trachomatis class II chaperone. Furthermore, we identified a novel C. trachomatis effector, CT460 that localises in the eukaryotic nucleus when ectopically expressed in 293 T cells

Nogo-A Regulates Neural Precursor Migration in the Embryonic Mouse Cortex

Although Nogo-A has been intensively studied for its inhibitory effect on axonal regeneration in the adult central nervous system, little is known about its function during brain development. In the embryonic mouse cortex, Nogo-A is expressed by radial precursor/glial cells and by tangentially migrating as well as postmigratory neurons. We studied radially migrating neuroblasts in wild-type and Nogo-A knockout (KO) mouse embryos. In vitro analysis showed that Nogo-A and its receptor components NgR, Lingo-1, TROY, and p75 are expressed in cells emigrating from embryonic forebrain–derived neurospheres. Live imaging revealed an increased cell motility when Nogo-A was knocked out or blocked with antibodies. Antibodies blocking NgR or Lingo-1 showed the same motility-enhancing effect supporting a direct role of surface Nogo-A on migration. Bromodeoxyuridine (BrdU) labeling of embryonic day (E)15.5 embryos demonstrated that Nogo-A influences the radial migration of neuronal precursors. At E17.5, the normal transient accumulation of radially migrating precursors within the subventricular zone was not detectable in the Nogo-A KO mouse cortex. At E19, migration to the upper cortical layers was disturbed. These findings suggest that Nogo-A and its receptor complex play a role in the interplay of adhesive and repulsive cell interactions in radial migration during cortical development

Effects of Experimental Releases of Oil and Dispersed Oil on Arctic Nearshore Macrobenthos. II. Epibenthos

An experimental subsurface release of chemically dispersed oil at Cape Hatt, northern Baffin Island, resulted in short-term relatively high oil concentrations in the waters of two adjacent bays, whereas untreated oil released onto the surface of a third bay could not be detected in the water below a depth of 1 m. The only immediate response in epibenthos observed by divers was narcosis in urchins and starfish following the dispersed oil release. Analysis of data from in situ counts in the three test bays and in a fourth (reference) bay during the open water seasons of 1980-83 showed that densities of the starfish Leptasterias polaris were not affected by either oil release and that effects on urchin densities were minor or transitory: Strongylocentrotus droebachiensis apparently made immediate and transitory attempts to avoid dispersed oil in the water and possibly tried to avoid untreated and dispersed oil in sediments two years after oiling. Analysis of airlift samples collected at 3 and 7 m depths in the four bays during 1980-83 showed no major effects of either oil release on densities of epibenthic crustaceans; taxa examined included all crustaceans, all cumaceans, one species of cumacean, all amphipods and eight individual amphipod taxa. The overall trend was toward increases in epibenthic crustacean densities over the study period. Effects that may have been attributable to oil were found in only 2 of 22 analyses of density data for individual taxa. In those cases, effects were minor: untreated oil in sediments apparently altered the depth distribution of Anonyx juveniles, and dispersed oil in the water column apparently had a delayed adverse effect on reproduction in the amphipod family Stenothoidae. Densities of Pontoporeia femorata were not affected by oil, but inspection of size-frequency data indicated a possible delayed adverse effect on its reproduction.Key words: arctic epibenthos, amphipods, echinoderms, oil effects, dispersed oil effects, experimental oil releases, Baffin Island, macrobenthosMots clés: épibenthos arctique, amphipodes, échinodennes, effets dus au pétrole, effets dus au pétrole dispersé, déversements expérimentaux de pétrole, île Baffin, macrobentho

Negotiating infant feeding in private and public spaces: a study of women’s experiences

There is a wealth of literature suggesting that breastfeeding for 6 months offers the ideal balance of nutrients for complete infant growth, and that all infants should be: “exclusively breastfed from birth to six months of age” (WHO 2003). However, although 98 percent of new mothers are capable of breastfeeding, only a minority of infants continue to be breastfed at six months following birth. In addition, breastfeeding rates are socially patterned whereby women living in the most affluent neighbourhoods are three times more likely to breastfeed their infants than women living in the least affluent areas (Bolling et al 2007). This thesis set out to address a range of research questions in relation to women’s lived experiences of breastfeeding in private and public spaces throughout the first 6 months of motherhood within a sample of mothers from the most and least affluent neighbourhoods. Given that breastfeeding is an embodied health behaviour, the epistemology adopted a position of interpretivism as a means of capturing the meaning and lived experiences of women’s breastfeeding. Breastfeeding women were recruited at 2 days following birth from the most and least affluent areas of Glasgow south and 41 in-depth interviews were conducted over 3 time periods following birth: 4 weeks (n18), 10 weeks (n12) and 26 weeks (n11). The results from this public policy health service research study suggest that breastfeeding is a learnt skill and women work hard to develop their skills and confidence in order to breastfeed comfortably and discreetly in private and public spaces. Breastfeeding is commonly discussed as a private domestic activity, and home is generally considered the most appropriate place for breastfeeding to take place. However, with the constant flow of visitors a new baby attracts, the boundaries between what are considered private and public space breaks down. As a result, women develop an awareness of appropriate and inappropriate spaces for breastfeeding both at home and outside the home. Women suggest, at times, they feel a greater degree of privacy breastfeeding within public spaces than they do in the private space of their own home