ENTRE REPRODUCTION ET MOBILISATION: LES RAPPORTS DE GENRE EN FORMATION CONTINUE EN FRANCE ET AU CANADA

La situation des femmes en éducation initiale a beaucoup évolué depuis 40 ans. Mais qu’en est-il de leur situation en éducation et formation des adultes? Cet article, comparant le Canada et la France, montre que si les femmes ont un taux de participation plus élevé que les hommes, ce qui est un fait connu, leur présence plus forte en formation à vocation professionnelle constitue, toutefois, un phénomène nouveau. L’analyse met en relief certaines particularités, telles qu’un recours plus important à la formation continue au Canada, ou encore une probabilité plus élevée, en France, de la participation des employés à temps complet. Dans les deux pays, la participation des femmes demeure modulée par divers facteurs sociaux.     

Protective effect of endolithic fungal hyphae on oolitic limestone buildings

This study presents characterizations of weathering forms of the same oolitic limestone from four quarries and eight monuments exposed on various environmental conditions focusing on the waterproofing effect of endolithic organic matter. Patinas were analyzed by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX), capillarity coefficient through weathered and unweathered sides, gypsum content and porous network morphology by epoxy resin molding. Study of weathering forms on old quarries indicates that lichens colonization (Verrucaria nigrescens and Caloplaca aurantia) can fill the superficial porous network with a dense network of lichenised fungal hyphae. Capillary coefficient measurement on natural and calcinated samples showed that endolithic organic matter can waterproof the stone and could act as a sulfate contamination barrier. Similar endolithic organic layer due to ancient lichens growth are found on some antique monuments of the Nîmes downtown and could explain their well-preserved state, unlike decayed 19th century churches that were never colonized by lichens.     

On the robustness of Riccati flows to complete model misspecification

Consider the continuous-time matrix Riccati operator Ricc$\left(Q\right)=AQ+Q{A}^{\prime }?QSQ+R$. In this work, we consider the robustness of this operator to direct perturbations of the matrices (A, R, S) and, in particular, the flow robustness of the corresponding Riccati differential equation. For a given class of perturbation, we show that the corresponding differential equation is well defined in the sense it is bounded above and below, it has a well-defined fixed point, and it converges to this fixed point exponentially fast. Moreover, the flow of the perturbed Riccati flow is close to the nominal Riccati flow when the perturbation is small; i.e. we prove a continuity-type condition in the size of the perturbation.