Identité ethnolinguistique, autodétermination et satisfaction de vie en contexte francophone minoritaire

L’étude a pour objet de vérifier empiriquement la validité d’un modèle théorique qui propose un système de relations liant la construction de l’identité ethnolinguistique à la satisfaction de vie, un aspect du mieux-être psychologique, et à l’autoévaluation de sa santé. Un échantillon de 8 124 élèves du secondaire, provenant de 30 conseils scolaires francophones situés à l’extérieur du Québec, a participé à l’étude. Les résultats sont conformes au modèle fondé sur la théorie de l’autodétermination, qui stipule que lorsque la construction identitaire se fait dans un contexte d’appui à des besoins psychologiques de base, elle est reliée au mieux-être psychologique de la personne.The purpose of this study was to provide an empirical verification of the validity of a theoretical model proposing a system of relationships linking the construction of an ethnolinguistic identity to satisfaction with life, an aspect of psychological well-being, and to health self-evaluation. A sample of 8124 high-school students from 30 Francophone school boards outside of Quebec participated in the study. The results support a model based on the theory of self-determination stipulating that when identity construction takes place in a context of support for basic psychological needs, it is linked to the person’s psychological well-being

FOULING OF A HYDROPHOBIC MICROFILTRATION MEMBRANE BY ALGAE AND ALGAL ORGANIC MATTER: MECHANISMS AND PREVENTION

Microfiltration is a membrane filtration process increasingly used in potable water treatment because it effectively removes turbidity and particles which include pathogens. However, the permeability of microfiltration membranes usually decreases during filtration as a result of the accumulation of aquatic material on or within the membrane, a phenomenon referred to as fouling. While the fouling of microfiltration membranes by surface waters has largely been attributed to the presence of natural organic matter (NOM) in these waters, the fouling caused specifically by algae and their associated algal organic matter (AOM) has not been rigorously investigated. The fouling of a hydrophobic microfiltration membrane system typical of those used in potable water treatment was therefore tested with a series of model organic compounds, selected to represent AOM, and three genera of algae grown in the laboratory, Scenedesmus, Asterionella, and Microcystis. Finally, the use of coagulation/flocculation pre-treatment using alum to reduce fouling by algae and AOM was examined. Model compounds including proteins and polysaccharides were capable of significant and irreversible fouling of the hydrophobic microfiltration membrane. Two fouling ii i mechanisms by these compounds were identified: (1) limited pore constriction caused by the adsorption of small organic molecules onto the membrane pore walls and (2) pore obstruction caused by large organic aggregates that form under specific solution conditions. Fouling of the hydrophobic membrane by the different algae varied significantly. Algal cells accumulated on the membrane surface during filtration and caused no fouling or fouling which was mostly reversible. By contrast, AOM was capable of significant and mostly irreversible fouling. Because the AOM produced by each alga varied significantly in concentration and size, their fouling varied significantly as well. Similarities in fouling mechanisms were observed between AOM and the model compounds. Coagulation/flocculation pre-treatment using alum may be an effective method to reduce the fouling caused by several types of organic matter, including AOM. Reductions in fouling are achieved when the alum dose exceeds the minimum effective alum dose (MEAD) established by jar test for removal of the organic matter by settling

Origin of weakened interannual sea-surface temperature variability in the Southeastern Tropical Atlantic Ocean

Observations and reanalysis products are used to investigate the substantial weakening in the southeastern tropical Atlantic sea‐surface temperature (SST) variability since 2000. Relative to 1982‐1999, the March‐April‐May SST variability in the Angola‐Benguela area (ABA) has decreased by more than 30 %. Both equatorial remote forcing and local forcing are known to play an important role in driving SST variability in the ABA. Compared to 1982‐1999, since 2000 equatorial remote forcing had less influence on ABA SSTs whereas local forcing has become more important. In particular, the robust correlation that existed between the equatorial zonal wind stress and the ABA SSTs has substantially weakened, suggesting less influence of Kelvin waves on ABA SSTs. Moreover, the strong correlation linking the South Atlantic Anticyclone and the ABA SSTs has reduced. Finally, multidecadal surface warming of the ABA could also have played a role in the weakening of the interannual SST variability

Apparent Densities of Stomoxys Species (Diptera, Muscidae) of Different Physiological Ages Caught with Vavoua Trap Differ With Landscape and Trapping Period

Stable flies (Stomoxys spp.) are common pests of livestock in the peri-urban rangelands of Vina Division of the Adamawa Plateau. No documented information is available on their diurnal dynamics in relation to physiological age and landscape. The main aim of this study was to determine the trap apparent density (ADT) of Stomoxys and associate it to their diurnal activity rhythm and landscape. Vavoua traps (n=12) were used for Stomoxys collection. Trapping was carried out for seven days i.e. three days consecutively in August and four days consecutively in October, 2016.Three traps were pitched in each of the three biotopes (river, cattle corral and gallery forest) of the four study sites (Galim, Mbidjoro, Velambai and Soukourwo). All female Stomoxys captured underwent ovarian dissection for the determination of their physiological ages (parous or nulliparous). A total of 218 Stomoxys were caught and identified into four species (S. niger niger, S. omega, S. calcitrans, and S.xanthomelas) with an overall ADT of 2.59 flies per trap per day and Stomoxys niger niger (1.13 s.n.n. per trap per day) recorded the highest ADT. Species richness was study site dependent.Higher catches of females 113 (51.83%) were made than that of their male 105 (48.17%) counterparts. Galim recorded the highest Stomoxys apparent density (4.90) as compared to other sites with a statistically significant difference (P<0.05). The proportion of parous 87 (59.30%) was higher than that of their nulliparous 46 (40.71%) counterparts. Parity differed with landscape and capture periods. S. n. niger was the most frequent in all biotopes and Galim recorded the highest ADT. The population of female flies was made up of adults (parous) with a bimodal diurnal activity rhythm whereas males had a unimodal activity rhythm.

Temporal Development of Scour Holes around Submerged Stream Deflectors

Although the deflector structures used in many fish habitat rehabilitation schemes are frequently overtopped, few studies have examined the scour patterns created around submerged models. Furthermore, laboratory studies typically test smooth-surfaced structures, when those installed in natural rivers are generally made of logs or boulders. This study uses rough-surfaced, paired deflectors to investigate the temporal evolution of scour for three overtopping ratios in identical approach flow conditions in a flume. Results show that when maintaining identical discharge, raising deflector height and thus reducing the overtopping ratio (flow depth / structure height), an increased depth and volume of scour is generated next to the structures. The location of maximum depth and the rate of scouring with time is similar for the two highest deflectors (overtopping ratios of 1.22 and 1.83), but different for the lowest deflector model (overtopping ratio of 3.67). In order to improve the success rate of river restoration projects using in-stream structures, the overtopping ratio should be used in equations that predict scour depth evolution with time

Management of Trickle Irrigated Orchards for Increased Water Use Efficiency

Trickle irrigation is the most efficient method of irrigating peach orchards in Texas. With a trickle irrigation system, a producer may make full use of a limited or low-volume water supply to apply precise amounts of water to the root zones of individual trees. Improved irrigation scheduling methods offer the potential for further savings in water and energy to pressurize the water since peach trees require less than a fully-watered state for production. This report describes research to determine the crop coefficients for peach trees that would result in an optimum irrigation schedule. One major effort evaluated the physiological response of the peach tree to varying irrigation regimes. This thrust indicated that a crop coefficient as low as 0.53 produced similar physiological responses (leaf water potential, leaf resistance, and transpiration rate) as a crop coefficient of 0.7. The critical period for initiation of stress was during the period before harvest. A large twin weighing lysimeter facility was designed and installed. Preliminary results for mature peach trees showed water use rates at the maximum evapotranspiration rate approached a crop coefficient of 1.0. The research indicates that the peach tree is a luxury consumer of water; improved irrigation scheduling is achievable

Plant Responses of Drip Irrigated Trees to Climate and Water Stress

Past irrigation research has shown that peach (prunus persica) trees vary in their field response to water stress, and the degree of stress is a function of the plants' environment. Water deficits reduce plant growth and crop yields, therefore, measurements of plant water stress are fundamental in understanding how the environment affects plant performance. This in turn will facilitate the irrigator to have very precise water control and to determine optimum irrigation quantities. This research examined the effect of environmental variables on leaf water potential, leaf resistance, canopy resistance and transpiration rate; and evaluated their ultimate effect on yield, water use efficiency and pruning weights for trees under four drip irrigation regimes at Stephenville, Texas. Treatments selected were instrumented with 1-, 2-, 3- and 4-emitters per tree, and single trees from each treatment were instrumented with ground covers. Plant responses were measured hourly on sunlit and shaded leaves of each treatment. Leaf water potentials and leaf resistances were higher in shaded leaves, resulting in reduced transpiration. An increase in early morning leaf water potentials indicated irrigation had decreased stress. Lower leaf water potentials and higher leaf resistance indicated the tress were being severely stressed prior to harvest. Leaf water potentials decreased linearly, whereas leaf resistance decreased exponentially, with increasing solar radiation. In stressed trees critical leaf water potentials were lower suggesting some degree of adaptation to stress. Leaf water potentials decreased linearly with increasing transpiration. Total resistance (sum of plant and soil resistance) increased with increasing severity of stress. The 3-emitter tree was recommended, since yield and water use efficiency are relatively high. Proper irrigation increased total yields and also the number of fruit within a marketable size range, while maintaining high water use efficiency, resulting in economic benefits to the farmer

Cytotoxic polyfunctionality maturation of cytomegalovirus-pp65-specific CD4 + and CD8 + T-cell responses in older adults positively correlates with response size

Cytomegalovirus (CMV) infection is one of the most common persistent viral infections in humans worldwide and is epidemiologically associated with many adverse health consequences during aging. Previous studies yielded conflicting results regarding whether large, CMV-specific T-cell expansions maintain their function during human aging. In the current study, we examined the in vitro CMV-pp65-reactive T-cell response by comprehensively studying five effector functions (i.e., interleukin-2, tumor necrosis factor-α, interferon-γ, perforin, and CD107a expression) in 76 seropositive individuals aged 70 years or older. Two data-driven, polyfunctionality panels (IL-2-associated and cytotoxicity-associated) derived from effector function co-expression patterns were used to analyze the results. We found that, CMV-pp65-reactive CD8 + and CD4 + T cells contained similar polyfunctional subsets, and the level of polyfunctionality was related to the size of antigen-specific response. In both CD8 + and CD4 + cells, polyfunctional cells with high cytotoxic potential accounted for a larger proportion of the total response as the total response size increased. Notably, a higher serum CMV-IgG level was positively associated with a larger T-cell response size and a higher level of cytotoxic polyfunctionality. These findings indicate that CMV-pp65-specific CD4 + and CD8 + T cell undergo simultaneous cytotoxic polyfunctionality maturation during aging

Cerebral toxoplasmosis in Acquired Immunodeficiency Syndrome (AIDS) patients also provides unifying pathophysiologic hypotheses for Holmes tremor

<p>Abstract</p> <p>Background</p> <p>Holmes tremor is a rare symptomatic movement disorder. Currently suggested pathophysiological mechanisms of the disease are mostly derived from stroke cases. Although rare, cerebral toxoplasmosis may strengthen the pathophysiologic mechanism of disease.</p> <p>Case presentation</p> <p>A case of Holmes tremor secondary to cerebral toxoplasmosis in an AIDS patient is presented. A relevant literature search was performed, using pubmed and several entries for Holmes tremor as labelled in the literature. The unifying feature of our case and those of the literature is the involvement of either the cerebello-thalamo-cortical and/or the dentato-rubro-olivary pathways. The abscess or the extension of surrounding edema beyond these two circuits may account for the superimposed dysfunction of the nigrostriatal system in some but not all cases. The short delay observed in our observation and the dramatic response to treatment may indirectly support the secondary neuronal degeneration theory in the mechanism of Holmes tremor.</p> <p>Conclusion</p> <p>Cases of cerebral toxoplasmosis in AIDS patients also provide arguments for the role of the thalamo-cortical and/or the dentato-rubro-olivary pathways dysfunction in the pathogenesis of Holmes tremor. Involvement of the nigro-striatal pathway may not be crucial in the development of this syndrome. Our case also brings additional indirect arguments for the role of secondary neuronal degeneration in the mechanism of Holmes tremor.</p

Associations of cannabis use disorder with cognition, brain structure, and brain function in African Americans

Although previous studies have highlighted associations of cannabis use with cognition and brain morphometry, critical questions remain with regard to the association between cannabis use and brain structural and functional connectivity. In a cross-sectional community sample of 205 African Americans (age 18–70) we tested for associations of cannabis use disorder (CUD, n = 57) with multi-domain cognitive measures and structural, diffusion, and resting state brain-imaging phenotypes. Post hoc model evidence was computed with Bayes factors (BF) and posterior probabilities of association (PPA) to account for multiple testing. General cognitive functioning, verbal intelligence, verbal memory, working memory, and motor speed were lower in the CUD group compared with nonusers (p \u3c .011; 1.9 \u3c BF \u3c 3,217). CUD was associated with altered functional connectivity in a network comprising the motor-hand region in the superior parietal gyri and the anterior insula (p \u3c .04). These differences were not explained by alcohol, other drug use, or education. No associations with CUD were observed in cortical thickness, cortical surface area, subcortical or cerebellar volumes (0.12 \u3c BF \u3c 1.5), or graph-theoretical metrics of resting state connectivity (PPA \u3c 0.01). In a large sample collected irrespective of cannabis used to minimize recruitment bias, we confirm the literature on poorer cognitive functioning in CUD, and an absence of volumetric brain differences between CUD and non-CUD. We did not find evidence for or against a disruption of structural connectivity, whereas we did find localized resting state functional dysconnectivity in CUD. There was sufficient proof, however, that organization of functional connectivity as determined via graph metrics does not differ between CUD and non-user group