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Search for vector-like leptons with long-lived particle decays in the CMS muon system in proton-proton collisions at = 13 TeV
No full textInternational audienceA first search is presented for vector-like leptons (VLLs) decaying into a light long-lived pseudoscalar boson and a standard model lepton. The pseudoscalar boson is assumed to have a mass of 2 GeV and to decay exclusively into a pair of photons. It is identified using the CMS muon system. The analysis is carried out using a data set of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment in 2016-2018, corresponding to an integrated luminosity of 138 fb. Selected events contain at least one pseudoscalar boson decaying electromagnetically in the muon system and at least one hadronically decaying lepton. No significant excess of data events is observed compared to the background expectation. Upper limits are set at 95% confidence level on the vector-like lepton production cross section as a function of the VLL mass and the pseudoscalar boson mean proper decay length. The observed and expected exclusion ranges of the VLL mass extend up to 700 and 670 GeV, respectively, depending on the pseudoscalar boson lifetime
Mechanochemical Approach for Metal‐Free Regioselective C5‐Sulfenylation of Imidazo[2,1‐b]thiazoles
No full textInternational audienceThe development of sustainable and selective methodologies for heterocyclic functionalization remains a key challenge in organic synthesis. In this study, we report a novel, metal‐free bis(trifluoroacetoxy)iodo]benzene (PIFA)‐mediated strategy for the regioselective C5‐sulfenylation of imidazo[2,1‐b]thiazoles using aryl methyl sulfides under mechanochemical conditions. This solvent‐free approach offers a rapid, efficient, and environmentally friendly alternative to current methods, achieving yields of up to 86% while completely avoiding hazardous solvents. The method exhibits broad substrate scope, with tolerance to both electron‐donating and electron‐withdrawing functional groups. This mechanochemical strategy provides a valuable synthetic tool for the functionalization of imidazo[2,1‐b]thiazole scaffold, with potential applications in medicinal and materials chemistry
3D-Shell Electromechanical Modeling of the Left Atrium
No full textInternational audienceThe thin-walled nature of the atrial wall can lead to numerical locking issues when using 3D models discretized with standard finite elements. In order to circumvent these issues, we introduce a comprehensive electromechanical model of the left atrium based on a 3D-shell formulation. The model integrates both the passive and active components of the atrial tissue, while blood flow and the mitral valve dynamics are described in a lumped parameter fashion. The resulting model is discretized with a finite element approach specifically designed to mitigate numerical locking. The effectiveness of the proposed approach is evaluated by comparing the numerical results with biomarkers reported in the literature, in the case of both healthy and pathological conditions
Modèles de communication et calculabilité dans les réseaux anonymes
No full textInternational audienceLe problème du calcul distribué de la fonction f consiste, pour un réseau de n agents autonomes, à ce que chaque agent calcule la valeur f (ω 1 , ..., ω n ) lorsque ω 1 , ..., ω n sont les valeurs d'entrée des agents, chacune étant initialement privée à un agent. Dans cet article, nous étudions cette question dans les réseaux synchrones anonymes où la communication se fait par échanges de messages, avec différentes hypothèses sur le degré de connaissance ou de contrôle que chaque agent a sur ses voisins. Dans le modèle de diffusion "à l'aveugle" où, à chaque tour, un agent se contente d'envoyer un message unique sans aucune connaissance ni contrôle sur ses destinataires, Boldi et Vigna ont prouvé que les fonctions calculables sont exactement celles dont la valeur ne dépend que de l'ensemble {ω 1 , ..., ω n } des arguments. Ce résultat est encore valable même s'il existe un leader ou si les agents connaissent la taille du réseau. Ici, nous examinons trois modèles de communication, plus forts mais tout aussi naturels, régis par les principes suivants : (1) à chaque tour, les agents connaissent le nombre de leurs voisins sortants ; (2) tous les liens de communication dans le réseau sont bidirectionnels ; ou (3) les agents peuvent s'adresser individuellement à chacun de leurs voisins sortants. Nous montrons que, dans les réseaux statiques et pour chacun de ces trois modèles de communication, la classe des fonctions calculables est exactement celle composée des fonctions dont la valeur ne dépend que de la fréquence relative de chaque valeur d'entrée ω i . Si, en outre, le réseau possède un leader ou si les agents connaissent la taille du réseau, chaque agent peut récupérer en fait le multi-ensemble complet {{ω 1 , ..., ω n }} et peut donc calculer n'importe quelle fonction invariante sous permutation de ses arguments. Autrement dit, une connaissance, même minimale, sur les destinataires des messages augmente considérablement la calculabilité en distribué. Dans une dernière partie, nous étudions comment étendre les résultats obtenus pour les réseaux statiques aux réseaux dynamiques
GEOMETRIC OPTIMIZATION OF A LITHIUM-ION BATTERY WITH THE DOYLE-FULLER-NEWMAN MODEL
No full textThis paper studies the geometric optimization of the separator in a lithium-ion battery, following the Doyle-Fuller-Newman model. For a general objective function, we compute its derivative with respect to the interface position by mean of the adjoint method. Our main numerical application is the maximization of the total electric energy during a discharge. Both cases of a fixed final time and a final time depending on the state of charge are examined. Our 2-d numerical implementation is performed in the finite element software FreeFEM with body-fitted meshes. Our main practical conclusion is that optimization over shorter time periods yields more interdigitated designs.</div
Runtime Analysis for Multi-Objective Evolutionary Algorithms in Unbounded Integer Spaces
No full textInternational audienceRandomized search heuristics have been applied successfully to a plethora of problems. This success is complemented by a large body of theoretical results. Unfortunately, the vast majority of these results regard problems with binary or continuous decision variables -- the theoretical analysis of randomized search heuristics for unbounded integer domains is almost nonexistent. To resolve this shortcoming, we start the runtime analysis of multi-objective evolutionary algorithms, which are among the most successful randomized search heuristics, for unbounded integer search spaces. We analyze single- and full-dimensional mutation operators with three different mutation strengths, namely changes by plus/minus one (unit strength), random changes following a law with exponential tails, and random changes following a power-law. The performance guarantees we prove on a recently proposed natural benchmark problem suggest that unit mutation strengths can be slow when the initial solutions are far from the Pareto front. When setting the expected change right (depending on the benchmark parameter and the distance of the initial solutions), the mutation strength with exponential tails yields the best runtime guarantees in our results -- however, with a wrong choice of this expectation, the performance guarantees quickly become highly uninteresting. With power-law mutation, which is an essentially parameter-less mutation operator, we obtain good results uniformly over all problem parameters and starting points. We complement our mathematical findings with experimental results that suggest that our bounds are not always tight. Most prominently, our experiments indicate that power-law mutation outperforms the one with exponential tails even when the latter uses a near-optimal parametrization. Hence, we suggest to favor power-law mutation for unknown problems in integer spaces
Wearable-Derived Behavioral and Physiological Biomarkers for Classifying Unipolar and Bipolar Depression Severity
No full textInternational audienceDepression is a complex mental disorder characterized by a diverse range of observable and measurable indicators that go beyond traditional subjective assessments. Recent research has increasingly focused on objective, passive, and continuous monitoring using wearable devices to gain more precise insights into the physiological and behavioral aspects of depression. However, most existing studies primarily distinguish between healthy and depressed individuals, adopting a binary classification that fails to capture the heterogeneity of depressive disorders. In this study, we leverage wearable devices to predict depression subtypes-specifically unipolar and bipolar depression-aiming to identify distinctive biomarkers that could enhance diagnostic precision and support personalized treatment strategies. To this end, we introduce the CALYPSO dataset, designed for non-invasive detection of depression subtypes and symptomatology through physiological and behavioral signals, including blood volume pulse, electrodermal activity, body temperature, and three-axis acceleration. Additionally, we establish a benchmark on the dataset using well-known features and standard machine learning methods. Preliminary results indicate that features related to physical activity, extracted from accelerometer data, are the most effective in distinguishing between unipolar and bipolar depression, achieving an accuracy of 96.77%. Temperature-based features also showed high discriminative power, reaching an accuracy of 93.55%. These findings highlight the potential of physiological and behavioral monitoring for improving the classification of depressive subtypes, paving the way for more tailored clinical interventions
Rank-based Linear-Quadratic Surrogate Assisted CMA-ES
No full textInternational audienceIn this poster, we introduce a rank-based surrogate-assisted variant of CMA-ES. Unlike previous methods that employ rank information as constraints to train an SVM classifier, our approach employs a linear-quadratic regression on the ranks. We investigate the method's invariance empirically. While this first algorithm outperforms CMA-ES with a few exceptions, it falls short to entirely meet the lq-CMA-ES performance levels. To address this, we propose an enhanced variant that handles together two alternative surrogates, one based on the ranks and one based on the original function values. Although this variant sacrifices strict invariance, it gains in robustness and achieves performance comparable to, or even exceeding, lq-CMA-ES on transformed problems. This last algorithm shows how simply incorporating new transformations of rank values could improve any surrogate-based CMA-ES variant.Dans ce poster, nous présentons une variante de CMA-ES assistée par un métamodèle basé sur les rangs. Contrairement aux approches précédentes qui exploitent l'information de rang comme contrainte pour entraîner un classifieur SVM, notre méthode repose sur une régression linéaire-quadratique appliquée aux rangs. Nous étudions empiriquement l'invariance de cette approche. Bien que ce premier algorithme surpasse CMA-ES dans la plupart des cas, il n’atteint pas pleinement les performances de lq-CMA-ES. Pour pallier cette limitation, nous proposons une variante améliorée combinant deux modèles alternatifs : l’un fondé sur les rangs, l’autre sur les valeurs originales de la fonction objectif. Cette nouvelle version renonce à l’invariance stricte, mais gagne en robustesse et atteint des performances comparables, voire supérieures, à celles de lq-CMA-ES sur des problèmes transformés. Ce dernier algorithme montre comment l’intégration simple de nouvelles transformations des rangs peut améliorer toute variante de CMA-ES reposant sur un métamodèle
Input to the ESPPU: The LUXE Experiment
No full textInternational audienceThis document presents an overview of LUXE (Laser Und XFEL Experiment), an experiment that will combine the high-quality and high-energy electron beam of the European XFEL with a high-intensity laser, to explore the uncharted terrain of strong-field quantum electrodynamics. The scientific case, facility, and detector setup are presented together with an overview of the foreseen timeline and expected capital costs
Varieties of Economic Elites? Preliminary Results From the World Elite Database (WED)
No full textInternational audienceThe strategies, decisions and beliefs of those who occupy prominent positions of economic power have influence on very large corporations and the markets they dominate, on vast amounts of economic resources, and on the rules of the game. However, the sociology of elites faces a dual challenge: divergent conceptualisations of what can be considered as a position of economic power and internationally incompatible sources of information hinder comparative analysis. The World Elite Database (WED) addresses this dual challenge, by generating, based on a consistent definition, standardised data for 16 countries. This research note introduces WED, its construction principles, and presents preliminary findings on how economic elites differ across countrie