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Beyond uniqueness: Relaxation calculus of junction conditions for coercive Hamilton-Jacobi equations
No full textInternational audienceA junction is a particular network given by the collection of half lines glued together at the origin. On such a junction, we consider evolutive Hamilton-Jacobi equations with coercive Hamiltonians. Furthermore,we consider a general desired junction condition at the origin, given by some monotone function .There is existence and uniqueness of solutions which only satisfy weakly the junction condition (at the origin, they satisfy either the desired junction condition or the PDE).We show that those solutions satisfy strongly a relaxed junction condition (that we can recognize as an effective junction condition). It is remarkable that this relaxed condition can be computed in three different but equivalent ways: 1) using viscosity inequalities, 2) using Godunov fluxes, 3) using Riemann problems.Our result goes beyond uniqueness theory, in the following sense: solutions to two different desired junction conditions and do coincide if
The Online Data Filter for the KM3NeT Neutrino Telescopes
No full textInternational audienceThe KM3NeT research infrastructure comprises two neutrino telescopes located in the deep waters of the Mediterranean Sea, namely ORCA and ARCA. KM3NeT/ORCA is designed for the measurement of neutrino properties and KM3NeT/ARCA for the detection of high\nobreakdashes-energy neutrinos from the cosmos. Neutrinos are indirectly detected using three\nobreakdashes-dimensional arrays of photo\nobreakdashes-sensors which detect the Cherenkov light that is produced when relativistic charged particles emerge from a neutrino interaction. The analogue pulses from the photo\nobreakdashes-sensors are digitised offshore and all digital data are sent to a station on shore where they are processed in real time using a farm of commodity servers and custom software. In this paper, the design and performance of the software that is used to filter the data are presented. The performance of the data filter is evaluated in terms of its purity, capacity and efficiency. The purity is measured by a comparison of the event rate caused by muons produced by cosmic ray interactions in the Earth's atmosphere with the event rate caused by the background from decays of radioactive elements in the sea water and bioluminescence. The capacity is measured by the minimal number of servers that is needed to sustain the rate of incoming data. The efficiency is measured by the effective volumes of the sensor arrays
Blending variational approaches and deep learning to enforce prior constraints in medical image segmentation
No full textInternational audienceImage segmentation plays a crucial role in computer vision, particularly in medical image analysis. While convolutional neural networks (CNNs) are the current state-of-the-art for segmentation, they may generate artifacts, such as isolated pixels or holes, when object contours are not well defined. Therefore, incorporating prior knowledge into the segmentation process is essential, whether through topological prescriptions (e.g., the number of connected components, the partial convexity of an object boundary) or geometrical constraints (e.g., penalizing volume through constraints), particularly when preserving contextual relationships between objects and achieving a segmentation that is homeomorphic to a known a priori is desired. In this paper, we propose two hybrid variational/deep learning frameworks that include geometric and topological constraints in the training of CNNs, in the form of two penalty terms in the loss function. The first model incorporates geometric constraints via a regularization based on weighted total variation, a volume/area penalty, and a Mumford-Shah like term. In the second model, we view the segmentation process as a registration task that pairs the ground truth and the image to be labelled, based on non-linear elasticity principles. Incompressibility conditions stated in terms of the Jacobian matrix determinant of the deformation ensures volume and topology preservation, without any material self-intersection. We evaluate the proposed losses in the challenging problem of thoracic organs at risk segmentation in Computed Tomographic scans, where some organs lack contrast, and their borders are ill-defined. Our ablation study demonstrates that our methods provide significant improvements over existing unconstrained approaches, in terms of both quantitative criteria such as the measurement of region overlap and qualitative assessment, particularly when dealing with unbalanced classes.</div
Rapid, sensitive and facile measurement of intra- and extracellular lactate and pyruvate in cells by LC-MS/MS
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Louis de Mas Latrie, historien de Chypre et de la Grèce franques: Actes du colloque organisé à Nicosie, Université de Chypre, 30-31 octobre 2024
No full textInternational audienceThis volume brings together the contributions presented at the colloquium in Nicosia dedicated to the founder of Cypriot medieval studies, Louis de Mas Latrie.Cet ouvrage réunit les contributions données à l'occasion du colloque de Nicosie consacré au fondateur de la médiévistique chypriote, Louis de Mas Latrie
Sur l'air de la Fronde. Chansons d'actualité et guerre civile (1648-1661)
No full textInternational audiencePeut-on connaitre les mots qui circulaient dans les rues de Paris pendant les révoltes anciennes ? Les chansons nous offrent une chance d’approcher ces discours qu’on diffusait sur des airs connus, à destination d’un public ciblé ou élargi. Ainsi, pendant la Fronde (1648-1653), des milliers de couplets ont circulé dans les rues de Paris, à l’écrit ou à l’oral, avant d’être collectés jusqu’au XVIIIe siècle. Les chefs des factions en lutte s’en servaient pour diffuser efficacement des éléments de langage sur les rapports de force du moment. Mais d’autres chansons d’actualité, mises en circulation par les petits métiers de Paris, peuvent aussi donner accès aux mots des subalternes. Accompagnée de 45 extraits sonores, cette étude sur les « mazarinades » chantées donne à entendre un nouveau discours sur la guerre civile en France au milieu du XVIIe siècl
Prediction of temperature-dependent nucleation and growth in pure FeCr alloy via a self-consistent Phase Field approach
No full textInternational audienceIn a nucleation and growth process, the nucleation rate dictating the decomposition kinetics is generally modeled using the classical nucleation theory approach, which is only valid near the solubility limit where experiments are very difficult to perform. An alternative to this difficulty is to describe the exact dynamics associated with the decomposition from the metastable state to the stable state. This dynamics depends on the system under consideration and is complex to calculate. The approach presented in this work circumvents these two difficulties. The nucleation rate is calculated using only the knowledge of an effective Hamiltonian within a phase field approach. It then does not require the exact knowledge of the dynamics. The key point of this generic work is to show that only two time scales are sufficient to describe the complex interactions between the nucleation, growth, and coarsening processes. Comparing these scales makes it then possible to simulate microstructures by considering the nucleation process either as an initial condition or as a source term in the phase field equations. This approach is validated by the very good agreement between the simulated and measured 3D microstructures at different times on ultra-pure samples of FeCr, a textbook case of a nucleation-growth process
La place de l’Histoire du droit et des institutions dans les pensées libertaires
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À Terre libérée : une dystopie glocale
No full textInternational audienceAujourd’hui le retour à la terre est recherché comme une panacée qui nous délivrerait des maux de l’urbanité, de la pollution et de l’anthropocène. En s’immergeant dans la terre chacun espère encore aujourd’hui1 libérer la terre de l’exploitation de l’anthropocène trouverait dans les communs2 une nouvelle expérience durable. Elever3 en respectant les cycles de la nature est rendu complexe dans le contexte : la perturbation globale des cycles de la nature par la pollution et le changement climatique est plus important encore aujourd’hui mais existe déjà dans la critique au début du XXe siècle que nous décrivons ici. 4 Andruchiw A., 2025, Voir son assiette comme un outil de lutte, pour une déviandisation de nos usage (...)2Ce lien entre critique de l’industrialisation par l’anthropocène et recherche de solution contre le carnivorisme4 implique une « déviandisation » : celle-ci est moins une privation qu’une nouvelle économie végétaliste de la terre. La libération pourrait être globale par le renversement du capitalisme mais aussi, comme nous le démontrons ici, par une modification des modes de vie, de production, de l’habitat et d’alimentation.3Cette libération de la terre du modèle industriel la construction de colonie agricole alternative aura commencé dans les causes anarchistes. Plutôt que de détruire par la violence politique, nous cherchons ici à décrire la dystopie végétarienne de Terre Libérée. Puissions nous libérer la terre
Projets alimentaires territoriaux et stratégies alimentaires locales : une comparaison France -Brésil
No full textInternational audienceThis text compares civil society and national and local policy actions targeting the food system in Brazil and France. It shows how the two countries have adopted mirror strategies, with France relying on a multitude of local initiatives led by local authorities and civil society, with little national support, while Brazil first developed a powerful national policy influenced by organised citizen networks to disseminate it at regional and local levels.Ce texte, en version longue par rapport à l'ouvrage à paraître, compare les actions de la société civile et politiques nationales et locales visant le système alimentaire, entre le Brésil et la France. Il montre comment les deux pays ont adopté des stratégies en miroir, la France se basant sur une multitude d'initiatives locales portées par les collectivités et la société civile, avec un faible portage national, pendant que le Brésil a d'abord développé une puissante politique nationale influencée par les réseaux citoyens organisés pour la diffuser aux échelles régionale et locale