Portail HAL UPEC
Not a member yet
55480 research outputs found
Sort by
Finding the convex envelope of a boundary datum using random geometric graphs
No full textIn this paper we approximate the convex envelope of a boundary datum inside a bounded domain in the Euclidean space. We work with a random graph that is obtained as random points with uniform distribution that are connected by proximity (x ∼ y when |x -y| < r). On the graph we solve an equation (that approximate the first eigenvalue of the Hessian of a smooth function) with an exterior datum. Under appropriate assumptions on r we show that the unique solution to the equation in the graph converges to the convex envelope of the boundary datum as the number of points goes to infinity
Entre qualité des soins et injonctions budgétaires : les paradoxes du NPM à l'écran, en France, au Royaume-Uni et aux USA
No full textInternational audienc
Unilateral accessory tragi in a cat
No full textInternational audienceAn accessory tragus-a congenital malformation of part of the external ear-is an abnormal appendage developed from the first pharyngeal (or branchial) arch. In humans, an accessory tragus can be associated with other abnormalities as part of congenital malformative syndromes, most of which are transmitted in an autosomal dominant mode. Three cutaneous exophytic lesions were detected in the right preauricular region of a 2.5-y-old, castrated male European shorthair cat. Two of these lesions were submitted for histologic examination and were diagnosed as accessory tragi. They consisted of a vertical axis of loose collagenous tissue with hair follicles and sebaceous glands covered by a simple fold of epidermis. The epidermis was of normal thickness and slightly hyperpigmented. Only the pretragal lesion contained a central core of well-differentiated elastic cartilage. To our knowledge, accessory tragus has not been reported previously in cats and has been reported only once in veterinary medicine, in a dog with a solitary unilateral lesion. For pathologists, the diagnosis of this rare lesion may not be straightforward, especially if the cartilaginous core is absent or the location of the sample is unknown.</div
Rock-slope failures as a proxy of a paraglacial denudation crisis. Examples in the Icelandic Westfjords (Dýrafjörður and Önundarfjörður areas)
No full textInternational audienc
Effet de la dimension géographique sur la conscience de la situation des apprenants en contexte d'apprentissage expérientiel
No full textInternational audienc
A Space-Time Cartesian Cut-Cell Method for Two-Phase Diffusion Problems using a Two-Fluid Approach
No full textInternational audienceWe present a Cartesian cut-cell finite-volume framework for sharp-interface two-phase diffusion problems in static geometries and prescribed interface motion on a fixed Cartesian grid. Following a two-fluid approach, one scalar field is solved independently in each phase and coupled through embedded interface conditions enforcing conservation together with general jump laws. In the static setting, the governing equations are integrated over phase-restricted control volumes and surfaces, yielding conservative discrete divergence and gradient operators. Interface coupling is achieved by introducing a small set of interfacial unknowns per cut cell on the embedded boundary, so that the resulting algebraic system involves bulk and interfacial averages. A key feature of the method is that all operators are assembled from a reduced geometric description based on low-order moments (volumes, apertures), avoiding explicit construction of cut volumes. For moving interfaces, we extend the discrete balance to phase-restricted space-time control volumes over each time interval; swept volumes and apertures provide the geometric weights that account naturally for cut-cell creation and destruction (fresh/dead-cell events) while preserving strict discrete conservation. The space-time formulation retains the algebraic structure of the static scheme, with motion entering only through local geometric weights and interface coupling operators. We validate the approach in steady and unsteady regimes, including curved embedded boundaries, Dirichlet/Neumann/Robin conditions, general jump laws and strong property and jump contrasts. The results demonstrate a super-linear convergence behavior, sharp enforcement of interfacial laws and excellent conservation properties, providing a robust building block for multiphase transport in evolving geometries and a foundation for future Stefan-type free-boundary extensions
« Les jeunes sont très lucides sur leur usage des réseaux sociaux et sont parfois mieux outillés que nous »
No full textAlors qu’Emmanuel Macron souhaite interdire aux moins de 15 ans l’accès aux réseaux sociaux, les chercheuses Rosa Maria Bortolotti et Sigolène Couchot-Schiex, qui étudient les pratiques des adolescents en ligne, émettent des réserves
Transducing Linear Decompositions of Tournaments
No full textBojańczyk, Pilipczuk, and Grohe [LICS '18] proved that for graphs of bounded linear clique-width, clique-decompositions of bounded width can be produced by a CMSO transduction. We show that in the case of tournaments, a first-order transduction suffices. This implies that the logics CMSO and existential MSO are equivalent over bounded linear clique-width tournaments