211 research outputs found
La victimisation en milieu scolaire : une analyse des facteurs individuels, contextuels et environnementaux
Contexte et objectifs. Ce mĂ©moire propose un modĂšle conceptuel Ă©cologique afin de mieux comprendre la violence dans les Ă©coles. Les objectifs de cette recherche sont de ; 1) estimer lâeffet des facteurs individuels, contextuels et environnementaux sur le risque de victimisation, 2) vĂ©rifier la prĂ©sence dâinteractions entre les diffĂ©rents facteurs.
MĂ©thodologie. Les Ă©lĂšves de 16 Ă©coles primaires de la grande rĂ©gion mĂ©tropolitaine de MontrĂ©al ont pris part Ă un sondage auto-rĂ©vĂ©lĂ© en lien avec diffĂ©rentes dimensions liĂ©es Ă la victimisation en milieu scolaire. Des analyses descriptives ont Ă©tĂ© menĂ©es, dans un premier temps, pour dresser le portrait de la violence en milieu scolaire. Dans un second temps, lâemploi dâun modĂšle linĂ©aire hiĂ©rarchique gĂ©nĂ©ralisĂ© (MLHG) a permis dâestimer les effets de variables propres Ă lâindividu, au contexte et Ă lâenvironnement sur le risque de victimisation.
RĂ©sultats. Les rĂ©sultats aux analyses multiniveaux montrent que des variables individuelles, contextuelles et environnementales influent sur la probabilitĂ© dâĂȘtre victime de violence verbale, physique et dans les mĂ©dias sociaux. Ainsi, les Ă©lĂšves les plus dĂ©linquants sont aussi ceux qui rapportent le plus dâantĂ©cĂ©dents de victimisation. Toutefois, ces rĂ©sultats ne sont pas entiĂšrement imputables aux caractĂ©ristiques des individus. Le risque de victimisation est attĂ©nuĂ© lorsque les « gardiens » interviennent pour mettre un terme au conflit et que les victimes se dĂ©fendent. Enfin, le risque de victimisation est moins Ă©levĂ© dans les Ă©coles oĂč il y a un grand nombre dâĂ©lĂšves.
InterprĂ©tation. Les rĂ©sultats suggĂšrent que plusieurs facteurs qui ne sont pas liĂ©s aux victimes et aux dĂ©linquants permettent de mieux comprendre le processus de victimisation en milieu scolaire. Le rĂŽle des gardiens de mĂȘme que la taille des Ă©coles sont des Ă©lĂ©ments centraux Ă la comprĂ©hension du passage Ă lâacte.Context and goals. This study proposes an ecological framework model for understanding school violence. The goals of this research are to; 1) assess the effect of individual, contextual and environmental factors on the risk of victimization, 2) verify the existence of interaction between the different factors.
Methods. The pupils of 16 elementary schools from the great Montreal metropolitan participated in a self-reported survey pertaining to different aspects of violence at school. Firstly, descriptive analyses were conducted to portray school violence. Secondly, a general hierarchal linear model was used to estimate the effects of individual, contextual and environmental variables on the risk of victimization.
Results. The results of multi-level analyses show that individual, contextual and environmental variables have an effect on the probabilities of being victim of verbal, physical or online violence. Thus, the more delinquent students are also those who report more prior cases of victimization. These results are not entirely attributable to individual characteristics, however. The risk of victimization is lessened when âguardiansâ interfere in order to put an end to the conflict, as well as when victims defend themselves. Finally, the risk of victimization is lower in schools with a greater number of students.
Interpretation. The results suggest that many aspects unrelated to victims and delinquents make it easier to comprehend the process of victimization at school. The role of guardians as well as the size of schools are important elements to the etiology of violent behaviour
New perspectives on the evolution of within-individual genome variation and germline/soma distinction
Genomes can vary significantly even within the same individual. The underlying mechanisms are manifold, ranging from somatic mutation and recombination, development-associated ploidy changes and genetic bottlenecks, over to programmed DNA elimination during germline/soma differentiation. In this perspective piece, we briefly review recent developments in the study of within-individual genome variation in eukaryotes and prokaryotes. We highlight a Society for Molecular Biology and Evolution 2020 virtual symposium entitled "Within-individual genome variation and germline/soma distinction" and the present Special Section of the same name in Genome Biology and Evolution, together fostering cross-taxon synergies in the field to identify and tackle key open questions in the understanding of within-individual genome variation
Vers un modĂšle Ă©cologique de la victimisation en milieu scolaire
Cet article sâinspire de la perspective Ă©cologique pour vĂ©rifier la contribution des effets de facteurs individuels, contextuels et environnementaux sur le risque de victimisation en milieu scolaire. Lâaccent est mis particuliĂšrement sur le rĂŽle des gardiens potentiels, des superviseurs et des victimes. Pour ce faire, un questionnaire a Ă©tĂ© administrĂ© aux Ă©lĂšves de 16 Ă©coles primaires dâune rĂ©gion urbaine du QuĂ©bec (N = 838) afin de sonder leurs expĂ©riences de violence en milieu scolaire. Les donnĂ©es ont Ă©tĂ© analysĂ©es Ă lâaide dâun modĂšle linĂ©aire hiĂ©rarchique gĂ©nĂ©ralisĂ© (MLHG), ce qui permet dâintĂ©grer simultanĂ©ment des variables sur le plan de lâĂ©cole et de lâĂ©lĂšve. Les rĂ©sultats indiquent que 44,2 %, 74 % et 22,3 % des Ă©lĂšves ont Ă©tĂ© respectivement victimes de violence physique, verbale et sur Internet au cours du dernier mois. Les rĂ©sultats montrent que lâadoption de comportements violents augmente le risque de victimisation verbale et physique chez les Ă©lĂšves. Les interventions des tĂ©moins (gardiens potentiels) rĂ©duisent significativement le risque de victimisation tout comme lâautodĂ©fense de la part des victimes. Demander de lâaide aux superviseurs (enseignants, surveillants ou parents) accroĂźt le risque de victimisation. Inciter les tĂ©moins Ă intervenir reprĂ©sente une piste qui pourrait ĂȘtre Ă©ventuellement intĂ©grĂ©e aux programmes de prĂ©vention
Temporal changes in gene expression profile during mature adipocyte dedifferentiation
Objective. To characterize changes in gene expression profile during human mature adipocyte dedifferentiation in ceiling culture. Methods. Subcutaneous (SC) and omental (OM) adipose tissue samples were obtained from 4 participants paired for age and BMI. Isolated adipocytes were dedifferentiated in ceiling culture. Gene expression analysis at days 0, 4, 7, and 12 of the cultures was performed using Affymetrix Human Gene 2.0 STvi arrays. Hierarchical clustering according to similarity of expression changes was used to identify overrepresented functions. Results. Four clusters gathered genes with similar expression between day 4 to day 7 but decreasing expression from day 7 to day 12. Most of these genes coded for proteins involved in adipocyte functions (LIPE, PLIN1, DGAT2, PNPLA2, ADIPOQ, CEBPA, LPL, FABP4, SCD, INSR, and LEP). Expression of several genes coding for proteins implicated in cellular proliferation and growth or cell cycle increased significantly from day 7 to day 12 (WNT5A, KITLG, and FGF5). Genes coding for extracellular matrix proteins were differentially expressed between days 0, 4, 7, and 12 (COL1A1, COL1A2, and COL6A3, MMP1, and TGFB1). Conclusion. Dedifferentiation is associated with downregulation of transcripts encoding proteins involved in mature adipocyte functions and upregulation of genes involved in matrix remodeling, cellular development, and cell cycle
RAD-QTL mapping reveals both genome-level parallelism and different genetic architecture underlying the evolution of body shape in Lake Whitefish (Coregonus clupeaformis) species pairs
Parallel changes in body shape may evolve in response to similar environmental conditions, but whether such parallel phenotypic changes share a common genetic basis is still debated. The goal of this study was to assess whether parallel phenotypic changes could be explained by genetic parallelism, multiple genetic routes, or both. We first provide evidence for parallelism in fish shape by using geometric morphometrics among 300 fish representing five species pairs of Lake Whitefish. Using a genetic map comprising 3438 restriction site-associated DNA sequencing single-nucleotide polymorphisms, we then identified quantitative trait loci underlying body shape traits in a backcross family reared in the laboratory. A total of 138 body shape quantitative trait loci were identified in this cross, thus revealing a highly polygenic architecture of body shape in Lake Whitefish. Third, we tested for evidence of genetic parallelism among independent wild populations using both a single-locus method (outlier analysis) and a polygenic approach (analysis of covariation among markers). The single-locus approach provided limited evidence for genetic parallelism. However, the polygenic analysis revealed genetic parallelism for three of the five lakes, which differed from the two other lakes. These results provide evidence for both genetic parallelism and multiple genetic routes underlying parallel phenotypic evolution in fish shape among populations occupying similar ecological niches.Keywords : Adaptive radiation, Parallel evolution, Fish body shape, Geometric morphometrics, Genotyping-by-sequencing
Archives et création : nouvelles perspectives sur l'archivistique. Cahier 1
Ce cahier de recherche fait Ă©tat des travaux menĂ©s au cours de la premiĂšre Ă©tape (2013-2014) du projet « Archives et crĂ©ation : nouvelles perspectives sur lâarchivistique ». Il comprend les textes suivants : Yvon Lemay et Anne Klein, « Introduction », p. 4-6; Yvon Lemay, « Archives et crĂ©ation : nouvelles perspectives sur lâarchivistique », p. 7-19; Anne-Marie Lacombe, « Exploitation des archives Ă des fins de crĂ©ation : un aperçu de la littĂ©rature », p. 20-59; Simon CĂŽtĂ©-Lapointe, « Archives sonores et crĂ©ation : une pratique Ă la croisĂ©e des chemins », p. 60-83; HĂ©lĂšne Brousseau, « Fibres, archives et sociĂ©tĂ© », p. 84-104; Annie Lecompte-Chauvin, « Comment les archives entrent dans nos vies par le biais de la littĂ©rature », p. 105-120; Aude Bertrand, « Valeurs, usages et usagers des archives », p. 121-150; Laure Guitard, « Indexation, Ă©motions, archives », p. 151-168; Anne Klein, Denis Lessard et Anne-Marie Lacombe, « Archives et mise en archives dans le champ culturel. SynthĂšse du colloque « Archives et crĂ©ation, regards croisĂ©s : tournant archivistique, courant artistique », p. 169-178. De plus, dans le but de situer le projet dans un contexte plus large, le cahier inclut une bibliographie des travaux effectuĂ©s sur les archives et la crĂ©ation depuis 2007, p. 179-182.Le projet de recherche est financĂ© par le Conseil de recherches en sciences humaines du Canada (Programme Savoir, 2013-2016)
Phase diagram of insulating crystal and quantum Hall states in ABC-stacked trilayer graphene
In the presence of a perpendicular magnetic field, ABC-stacked trilayer
graphene's chiral band structure supports a 12-fold degenerate N=0 Landau level
(LL). Along with the valley and spin degrees of freedom, the zeroth LL contains
additional quantum numbers associated with the LL orbital index .
Remote inter-layer hopping terms and external potential difference
between the layers lead to LL splitting by introducing a gap
between the degenerate zero-energy triplet LL orbitals. Assuming that the spin
and valley degrees of freedom are frozen, we study the phase diagram of this
system resulting from competition of the single particle LL splitting and
Coulomb interactions within the Hartree-Fock approximation at integer filling
factors. Above a critical value of the external potential
difference i,e, for , the ground state is a
uniform quantum Hall state where the electrons occupy the lowest unoccupied LL
orbital index. For (which corresponds to large
positive or negative values of ) the uniform QH state is unstable
to the formation of a crystal state at integer filling factors. This phase
transition should be characterized by a Hall plateau transition as a function
of at a fixed filling factor. We also study the properties of
this crystal state and discuss its experimental detection.Comment: 16 pages with 13 figure
Circulating steroid levels as correlates of adipose tissue phenotype in premenopausal women
Background: Obesity-related alterations in the circulating steroid hormone profile remain
equivocal in women. Our objective was to identify circulating steroid levels that relate to
increased adiposity and altered adipose phenotype in premenopausal women. Materials and
methods: In a sample of 42 premenopausal women (age 46±3 years; BMI 27.1±4.2 kg/m2
), 19
plasma steroids were quantified by ESI-LC-MS/MS. Body composition and fat distribution were
assessed by dual-energy X-ray absorptiometry and computed tomography, respectively. Markers
of adipose tissue function including adipocyte size distributions, radiological attenuation, and
macrophage infiltration were also analyzed in surgically obtained visceral and subcutaneous fat
samples. Results: Many negative correlations were observed between adiposity measurements
such as BMI, body fat percentage or total abdominal adipose tissue area and plasma levels of
androstenedione (r=-0.33 to -0.39, pâ€0.04), androsterone (r=-0.30 to -0.38, pâ€0.05) and plasma
levels of steroid precursor pregnenolone (r=-0.36 to -0.46, pâ€0.02). Visceral adipocyte
hypertrophy was observed in patients with low pregnenolone concentrations (p<0.05). Visceral
adipose tissue radiologic attenuation, a potential marker of adipocyte size, was also positively
correlated with pregnenolone levels (r=0.33, p<0.05). Low levels of pregnenolone were related to
increased number of macrophages infiltrating visceral and subcutaneous adipose tissue (p<0.05).
Conclusion: Plasma levels of androgens and their precursors are lower in women with increased
adiposity and visceral adipocyte hypertrophy. Low circulating pregnenolone concentration may
represent a marker of adipose tissue dysfunction
Impact of sex and sex hormones on pathophysiology and progression of aortic stenosis in a murine model
The lesions observed in AS have been shown to be sex specific, with women presenting extensive fibrotic remodeling while men developing more calcification deposit. We thus aimed to evaluate the influence of sex and sex hormones on the pathophysiology of aortic valve stenosis (AS) in our mouse model of AS. LDLr-/- ApoB100/100 IGF-II+/- mice (n = 210) were separated in six different groups: (1) intact male (IM), (2) intact female (IF), (3) castrated male (CM), (4) ovariectomized females (OF), (5) CM with testosterone supplementation (CMT), and (6) OF with 17ÎČ-estradiol supplementation (OFE). Mice were fed a high-fat/high-sucrose/high-cholesterol diet for 6 months. Hemodynamic progression of AS was followed by transthoracic echocardiography (at 12 and 36 weeks) and analyzed in all mice alive at 36 weeks. Aortic valves were collected for histological and digital droplet PCR* analysis. Increases in peak velocity were comparable in IF and IM (24.2 ± 5.7 vs. 25.8 ± 5.3 cm/s; p = 0.68), but IF presented with less severe AS. Between the three groups of male mice, AS progression was more important in IM (increase in peak velocity: 24.2 ± 5.7 cm/s; p < 0.001) compared to CM (6.2 ± 1.4; p = 0.42), and CMT (15.1 ± 3.5; p = 0.002). In the three groups of female mice, there were no statistical differences in AS progression. Digital PCR analysis revealed an important upregulation of the osteogenic gene RunX2 in IM (p < 0.0001) and downregulation of the pro-calcifying gene ALPL in IF (p < 0.05). Male sex and testosterone play an important role in upregulation of pro-calcifying genes and hemodynamic progression of AS. However, female mice appeared to be protected against calcification, characterized by downregulation of pro-osteogenic genes, but presented a similar AS hemodynamic progressio
Measurement of proteinuria
In pregnancy, there is a focus on measurement of proteinuria as it has been regarded as critical to the diagnosis of pre-eclampsia, the most dangerous of the hypertensive disorders of pregnancy. However, it is increasingly recognised that proteinuria is not essential for the diagnosis of pre-eclampsia, which can be based on other end-organ complications (such as elevated liver enzymes). Although heavy proteinuria has been linked with an increased risk of stillbirth in a âsigns and symptoms onlyâ model of maternal risk (i.e., miniPIERS), we lack the ability to identify a level of proteinuria above which maternal and/or perinatal risk is heightened. Therefore, at present, we rely on the detection of proteinuria that exceeds what is normally excreted by healthy pregnant women. Proteinuria detection methods are also a matter of keen debate, with all available methods having advantages and disadvantages.Publisher PD
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