Facteurs individuels et sociaux de l'adaptation réussie à la transition secondaire - collégial

"La présente recherche a été subventionnée par le ministère de l'Éducation, du Loisir et du Sport dans le cadre du Programme d'aide à la recherche sur l'enseignement et l'apprentissage (PAREA)."Titre de l'écran-titre (visionné le 5 nov. 2007)Également disponible en format papierBibliogr.: p. 98-10

Soil weathering rates in 21 catchments of the Canadian Shield

Soil mineral weathering represents an essential source of nutrient base cation (Ca, Mg and K) for forest growth in addition to provide a buffering power against precipitation acidity for soils and surface waters. Weathering rates of base cations were obtained for 21 catchments located within the temperate and the boreal forest of the Canadian Shield with the geochemical model PROFILE. Weathering rates ranged from 0.58 to 4.46 kmol<sub>c</sub> ha<sup>−1</sup> yr<sup>−1</sup> and their spatial variation within the studied area was mostly in agreement with spatial variations in soil mineralogy. Weathering rates of Ca and Mg were significantly correlated (<i>r</i> = 0.80 and 0.64) with their respective lake concentrations. Weathering rates of K and Na did not correlate with lake concentrations of K and Na. The modeled weathering rates for each catchment were also compared with estimations of net catchment exportations. The result show that modeled weathering rates of Ca were not significantly different than the net catchment exportations while modeled weathering rates of Mg were higher by 51%. Larger differences were observed for K and Na weathering rates that were significantly different than net catchment exportations being 6.9 and 2.2 times higher than net exportations, respectively. The results for K were expected given its high reactivity with biotic compartments and suggest that most of the K produced by weathering reactions was retained within soil catchments and/or above ground biomass. This explanation does not apply to Na, however, which is a conservative element in forest ecosystems because of the insignificant needs of Na for soil microorganisms and above ground vegetations. It raises concern about the liability of the PROFILE model to provide reliable values of Na weathering rates. Overall, we concluded that the PROFILE model is powerful enough to reproduce spatial geographical gradients in weathering rates for relatively large areas as well as adequately predict absolute weathering rates values for the sum of base cations, Ca and Mg

Neurobehavioral Function in School-Age Children Exposed to Manganese in Drinking Water

Background: Manganese neurotoxicity is well documented in individuals occupationally exposed to airborne particulates, but few data are available on risks from drinking-water exposure. Objective: We examined associations of exposure from concentrations of manganese in water and hair with memory, attention, motor function, and parent- and teacher-reported hyperactive behaviors. Methods: We recruited 375 children and measured manganese in home tap water (MnW) and hair (MnH). We estimated manganese intake from water ingestion. Using structural equation modeling, we estimated associations between neurobehavioral functions and MnH, MnW, and manganese intake from water. We evaluated exposure–response relationships using generalized additive models. Results: After adjusting for potential confounders, a 1-SD increase in log10 MnH was associated with a significant difference of –24% (95% CI: –36, –12%) SD in memory and –25% (95% CI: –41, –9%) SD in attention. The relations between log10 MnH and poorer memory and attention were linear. A 1-SD increase in log10 MnW was associated with a significant difference of –14% (95% CI: –24, –4%) SD in memory, and this relation was nonlinear, with a steeper decline in performance at MnW > 100 μg/L. A 1-SD increase in log10 manganese intake from water was associated with a significant difference of –11% (95% CI: –21, –0.4%) SD in motor function. The relation between log10 manganese intake and poorer motor function was linear. There was no significant association between manganese exposure and hyperactivity. Conclusion: Exposure to manganese in water was associated with poorer neurobehavioral performances in children, even at low levels commonly encountered in North America. Citation: Oulhote Y, Mergler D, Barbeau B, Bellinger DC, Bouffard T, Brodeur ME, Saint-Amour D, Legrand M, Sauvé S, Bouchard MF. 2014. Neurobehavioral function in school-age children exposed to manganese in drinking water. Environ Health Perspect 122:1343–1350; http://dx.doi.org/10.1289/ehp.130791

Which Factors Are Associated with Monitoring Goal Progress?

Three studies examined how people assess their progress on personal goals (e.g., whether they compare their progress to the past and/or to a desired target state), along with factors that might influence the nature of progress monitoring (e.g., whether the goal involves attaining a positive outcome or avoiding a negative outcome). Study 1 involved semi-structured interviews with 40 participants, in which we examined how participants monitored their progress and whether this was related to: (a) their level of self-efficacy, (b) whether the goal was prevention focused, and (c) whether goal progress was represented in quantifiable terms. Studies 2 (N = 492) and 3 (N = 481) were conducted online and additionally examined whether how participants monitored their progress differed as a function of the domain of the goal (i.e., whether it was related to physical development/health, finances, work/study, or social relationships). The findings suggest that participants: (i) were less likely to monitor their progress toward goals that were related to avoiding negative outcomes, (ii) were less likely to monitor their progress toward goals related to finances, work, or study with reference to the past, than progress toward other goals (e.g., those relating to physical development and health), (iii) found it easier to monitor their progress toward goals that they felt confident of attaining, but harder to monitor their progress toward goals related to work or study. Finally, the more participants thought about their goal in quantifiable terms, the more likely they were to monitor their progress, and the easier they found monitoring their progress to be. Taken together, these studies begin to describe the nature of progress monitoring and the factors that influence this important self-regulatory process

Intellectual Impairment in School-Age Children Exposed to Manganese from Drinking Water

ABSTRACT: BACKGROUND: Manganese is an essential nutrient, but in excess it can be a potent neurotoxicant. Despite the common occurrence of manganese in groundwater, the risks associated with this source of exposure are largely unknown. OBJECTIVES: Our first aim was to assess the relations between exposure to manganese from drinking water and children's intelligence quotient (IQ). Second, we examined the relations between manganese exposures from water consumption and from the diet with children's hair manganese concentration. METHODS: This cross-sectional study included 362 children 6-13 years of age living in communities supplied by groundwater. Manganese concentration was measured in home tap water (MnW) and children's hair (MnH). We estimated manganese intake from water ingestion and the diet using a food frequency questionnaire and assessed IQ with the Wechsler Abbreviated Scale of Intelligence. RESULTS: The median MnW in children's home tap water was 34 microg/L (range, 1-2,700 microg/L). MnH increased with manganese intake from water consumption, but not with dietary manganese intake. Higher MnW and MnH were significantly associated with lower IQ scores. A 10-fold increase in MnW was associated with a decrease of 2.4 IQ points (95% confidence interval: -3.9 to -0.9; p < 0.01), adjusting for maternal intelligence, family income, and other potential confounders. There was a 6.2-point difference in IQ between children in the lowest and highest MnW quintiles. MnW was more strongly associated with Performance IQ than Verbal IQ. CONCLUSIONS: The findings of this cross-sectional study suggest that exposure to manganese at levels common in groundwater is associated with intellectual impairment in children

Self-affirmation improves performance on tasks related to executive functioning

Objectives: The current study explored the effect of self-affirmation on two aspects of performance that have been related to executive functioning: working memory (assessed by a 2-back task) and inhibition (assessed by a Stroop task). The goal was to establish whether self-affirmation improved performance on these tasks. Method: Participants (N = 83) were randomized to either a self-affirmation or a control task and then completed the computerized tasks, in a fixed sequence. Results: Self-affirmed participants performed better than non-affirmed participants on both tasks. Conclusion: Self-affirmation can improve aspects of performance related to executive functioning. This finding may help to explain the wide range of beneficial effects that self-affirmation can have on cognition and behavior

Memory Self-Efficacy in its Social Cognitive Context

This chapter takes a primarily cognitive construct - memory self-efficacy (MSE) - and returns it to its roots - social cognition (Bandura, 1986). This is a natural and obvious move. MSE has evolved since the mid-1980s (Berry, West, & Powlishta, 1986; Hertzog, Dixon, Schulenberg, & Hultsch, 1987) to its present identity and status in the cognitive aging and adult developmental research literature. If it is to avoid becoming a hypothesis in search of data (Light, 1991) or worse, an epiphenomenon to more robust explanations of cognitive aging (e.g., speed) (Salthouse, 1993), its potential and limits must be scrutinized and subjected to rigorous new research agendas. Arguably, MSE has arrived at its present destination via metamemory (Dixon, Hertzog, & Hultsch, 1986; Hertzog, Dixon, & Hultsch, 1990a; Hertzog et al., 1987; Hultsch, Hertzog, Dixon, & Davidson, 1988), thereby acquiring a more cognitive emphasis than its clinical and social underpinnings suggest. This chapter presents MSE research from my lab that has been conducted from the orienting framework of self-efficacy theory and methodology (Bandura, 1977, 1986, 1997; Bandura, Adams, Hardy, & Howells, 1980; Bandura, Reese, & Adams, 1982). The value of this framework lies in its rich theoretical foundation, its unique measurement approach, and its ties to social cognition. The goal of the chapter is to evaluate the present status of MSE research and to suggest new research directions