Maintien de l’engagement paternel après la rupture : point de vue de pères et de mères en contexte de pauvreté

Depuis les dernières décennies, les ruptures d’unions conjugales se sont multipliées au Canada et au Québec, affectant maintenant 53 % des ménages (Duchesne, 2006). Ainsi, près de trois hommes sur cinq (56 %) se retrouvent dans un rôle de père gardien après la rupture (Duchesne, 2006). En dépit de changements législatifs et normatifs visant à favoriser un partage des responsabilités parentales après un divorce, la garde des enfants confiée à la mère demeure encore l’arrangement le plus courant. Les mères deviennent ainsi les principales, et souvent uniques, responsables des enfants, alors que la plupart des pères passent d’un rapport continu, régulier et intense avec leurs enfants, à une relation discontinue souvent imposée par la cour (Quéniart et Fournier, 1996).Cet article explore le phénomène du maintien de l’engagement du père après une rupture conjugale dans un contexte de pauvreté. Après avoir situé la problématique, les résultats de deux études qualitatives sur ce sujet sont présentés (Allard, Bourret et Tremblay, 2004; 2005), l’une à partir des propos de pères qui se disent encore engagés envers leurs enfants après la rupture, l’autre à partir de la parole de mères qui considèrent leur ex-conjoint encore impliqué auprès de leurs enfants. Les participants de ces deux études n’étaient pas appariés. Par la suite, les résultats sont confrontés afin de mettre en évidence les convergences et les divergences dans les points de vue des pères et des mères. Enfin, l’article conclut avec des éléments susceptibles d’inspirer les intervenants. Rappelons que la valorisation de l’engagement paternel après la rupture conjugale des parents vise à réduire le risque que ces enfants se retrouvent doublement pauvres : pauvres économiquement et « pauvres » (privés) de père (Allard et Binet, 2002; Marsiglio et Cohan, 2000)

Fine-scale assessment of genetic diversity of trembling aspen in northwestern North America

Background: In North America, the last ice age is the most recent event with severe consequences on boreal species’ ranges. Phylogeographic patterns of range expansion in trembling aspen (Populus tremuloides) suggested that Beringia is likely to be a refugium and the "ice-free corridor" in Alberta may represent a region where small populations persisted during the last glacial maximum (LGM). The purpose of this study was to ascertain whether the origins of trembling aspen in western North America are reflected in the patterns of neutral genetic diversity and population structure. A total of 28 sites were sampled covering the northwestern part of aspen’s distribution, from Saskatchewan to Alaska. Twelve microsatellite markers were used to describe patterns of genetic diversity. The genetic structure of trembling aspen populations was assessed by using multivariate analyses, Mantel correlograms, neighbor-joining trees and Bayesian analysis. Results: Microsatellite markers revealed little to no neutral genetic structure of P. tremuloides populations in northwestern North America. Low differentiation among populations and small isolation by distance (IBD) were observed. The most probable number of clusters detected by STRUCTURE was K = 3 (?K = 5.9). The individuals in the populations of the 3 clusters share a common gene pool and showed a high level of admixture. No evidence was found that either Beringia or the "ice-free corridor" were refugia. Highest allelic richness (AR) and lowest heterozygosity (Ho) were observed in Alberta foothills of the Rocky Mountains. Conclusions: Contrary to our hypothesis, our results showed that microsatellite markers revealed little to no genetic structure in P. tremuloides populations. Consequently, no divergent populations were observed near supposed refugia. The lack of detectable refugia in Beringia and in the "ice-free corridor" was due to high levels of gene flow between trembling apsen populations. More favorable environmental conditions for sexual reproduction and successful trembling aspen seedling establishment may have contributed to increase allelic richness through recombination in populations from the Albertan foothills of the Rocky Mountains

Influence of northern limit range on genetic diversity and structure in a widespread North American tree, sugar maple (Acer saccharum Marshall)

Due to climate change, the ranges of many North American tree species are expected to shift northward. Sugar maple (Acer saccharum Marshall) reaches its northern continuous distributional limit in northeastern North America at the transition between boreal mixed-wood and temperate deciduous forests. We hypothesized that marginal fragmented northern populations from the boreal mixed wood would have a distinct pattern of genetic structure and diversity. We analyzed variation at 18 microsatellite loci from 23 populations distributed along three latitudinal transects (west, central, and east) that encompass the continuous–discontinuous species range. Each transect was divided into two zones, continuous (temperate deciduous) and discontinuous (boreal mixed wood), based on sugar maple stand abundance. Respective positive and negative relationships were found between the distance of each population to the northern limit (D_north), and allelic richness (AR) and population differentiation (FST). These relations were tested for each transect separately; the pattern (discontinuous–continuous) remained significant only for the western transect. structure analysis revealed the presence of four clusters. The most northern populations of each transect were assigned to a distinct group. Asymmetrical gene flow occurred from the southern into the four northernmost populations. Southern populations in Québec may have originated from two different postglacial migration routes. No evidence was found to validate the hypothesis that northern populations were remnants of a larger population that had migrated further north of the species range after the retreat of the ice sheet. The northernmost sugar maple populations possibly originated from long-distance dispersal

L'individu dans la modernité : Georges Herbert Mead, Charles Taylor et Alain Touraine

Dans ce travail nous avons relaté une notion de l'individu moderne tel que définit dans la sociologie de Georges Herbert Mead, Charles Taylor et Alain Touraine. Avec les écritures de ces derniers, nous enfonçons l'individu profondément dans le social et nous produisons les arguments nécessaires à une conception interactive, intersubjective et dialogique de l'individu. Nous appuyant sur ces principes nous formulons un outil d'argumentation pertinente pouvant nous situer à l'intérieur des débats actuels en ce qui concerne l'individu et sa relation au social. Bien que notre travail ne soit pas soutenu de manière empirique, nous articulons notre position théorique en analysant le travail de Stella, une association regroupant des travailleuses du sexe à Montréal (Québec, Canada). Nous développons un argument théorique (exploratoire) sur les effets possibles engendrés par la criminalisation de la prostitution. Cet argument nous assiste dans l'élaboration d'une position théorique en ce qui concerne la relation soi/social

Genetic consequences of selection cutting on sugar maple (Acer saccharum Marshall)

Selection cutting is a treatment that emulates tree-by-tree replacement for forests with uneven-age structures. It creates small openings in large areas and often generates a more homogenous forest structure (fewer large leaving trees and defective trees) that differs from old-growth forest. In this study, we evaluated whether this type of harvesting has an impact on genetic diversity of sugar maple (Acer saccharum Marshall). Genetic diversity among seedlings, saplings, and mature trees was compared between selection cut and old-growth forest stands in Québec, Canada. We found higher observed heterozygosity and a lower inbreeding coefficient in mature trees than in younger regeneration cohorts of both forest types. We detected a recent bottleneck in all stands undergoing selection cutting. Other genetic indices of diversity (allelic richness, observed and expected heterozygosity, and rare alleles) were similar between forest types. We concluded that the effect of selection cutting on the genetic diversity of sugar maple was recent and no evidence of genetic erosion was detectable in Québec stands after one harvest. However, the cumulative effect of recurring applications of selection cutting in bottlenecked stands could lead to fixation of deleterious alleles, and this highlights the need for adopting better forest management practices