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Faire l'histoire des activités physiques et sportives par les archives : Quelle place donnée au corps ?
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Observation of tWZ production at the CMS experiment
No full textInternational audienceThe first observation of single top quark production in association with a W and a Z boson in proton-proton collisions is reported. The analysis uses data at center-of-mass energies of 13 and 13.6 TeV recorded with the CMS detector at the CERN LHC, corresponding to a total integrated luminosity of 200 fb. Events with three or four charged leptons, which can be electrons or muons, are selected. Advanced machine-learning algorithms and improved reconstruction methods, compared to an earlier analysis, result in an unprecedented sensitivity to tWZ production. The measured cross sections for tWZ production are 248 52 fb and 244 74 fb for =13 and 13.6 TeV, respectively. The signal is established with a statistical significance of 5.8 standard deviations, with 3.5 expected, compared to the background-only hypothesis
Quand Érec rencontre Erec(k). Réflexions croisées sur l’édition et l’interprétation des romans deChrétien de Troyes et de Hartmann von Aue
No full textInternational audienceHartmanns von Aue Erec, die deutschsprachige Übertragung des ersten Artusromans Chrétiens de Troyes Érec et Énide, ist ein paradigmatisches Beispiel für die intensive Zirkulation von Erzählstoffen im westeuropäischen Kulturraum des Mittelalters. Aus unterschiedlichen Gründen hat für beide Romane jeweils eine Handschrift (Paris, BnF fr. 794 und Wien, ÖNB, Cod. Ser. nova 2663) eine zentrale Rolle in der editorischen und kritischen Tradition gespielt. Vorliegender Beitrag zieht eine vergleichende Bilanz der Editionsgeschichte beider Texte, der damit verbundenen Debatten sowie ihrer Folgen für die Interpretation der Texte und die Erfassung beider Autorfiguren. Aus den gekreuzten Blicken geht hervor, wie produktiv eine komparatistische Perspektive sein kann, welche die Transformationen der Texte sowohl durch ihre Überlieferung als auch durch die Editionspraxis mit einbezieht.La traduction-réécriture en langue allemande, par Hartmann von Aue à la fin du XIIe siècle, du premier roman composé par Chrétien de Troyes, Érec et Énide, est un exemple bien connu de l’intense circulation de la matière narrative dans l’espace occidental médiéval. Pour chacun des textes, un manuscrit a joué un rôle central dans les traditions éditoriale et critique (Paris, BnF fr. 794 pour le texte de Chrétien, Wien, ÖNB, Cod. Ser. nova 2663 pour celui de Hartmann). Le présent article dresse un bilan de l’histoire des éditions des deux romans, des débats auxquels elles ont donné lieu et de leurs conséquences sur l’interprétation des textes et la perception de leurs auteurs. Ce bilan croisé vise à mettre en valeur l’intérêt, pour la démarche comparatiste, de tenir compte des particularités de la tradition textuelle et de l’influence des pratiques des éditeurs modernes
Differences between image-based and imageless robotics for total knee arthroplasty – an overview
No full textInternational audienceRobot-assisted total knee arthroplasty (TKA) has revolutionized implant positioning by enhancing surgical precision. However, significant differences exist between image-based and imageless robotic systems, influencing their accuracy, workflow, and potentially clinical outcomes. As such, this review aims to provide a structured comparison between image-based and imageless systems for TKA relevant to the surgeon. Image-based systems utilize preoperative imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI) to construct three-dimensional (3D) anatomical models for surgical planning and intraoperative guidance. In contrast, imageless systems rely on intraoperative anatomical landmark registration, reducing costs and radiation exposure but yielding a potential higher inaccuracy to define the joint-specific coordinate system. This current concepts review examines key differences between these technologies, focusing on coordinate system accuracy, anatomical landmark identification, resection precision, and clinical implications. Image-based systems may demonstrate superior accuracy in defining coordinate systems, particularly for femoral and tibial rotational axes, yet involve higher costs and logistical complexity. Imageless systems offer real-time adaptability and avoid preoperative imaging but may be more susceptible to anatomical registration errors. Comparative clinical studies suggest similar coronal plane alignment error between the two approaches, though image-based systems may offer advantages in tibial slope precision. Radiation exposure is an important consideration, as it varies significantly based on imaging protocols and may warrant greater attention from surgeons, especially for patients who receive frequent CT follow-up. As well, while both system types allow for assessing patellofemoral tracking, in addition patient-specific 3D models allow to restore the native trochlea orientation. Although both systems improve implant positioning compared to conventional techniques, evidence on mid- and long-term improved clinical outcomes compared to the conventional technique is still lacking
String Diagrams for Monoidal Categories, in Rocq
No full textWe present a Rocq library for monoidal categories, which includes a decision procedure for proving equality of morphisms as well as notations that make it possible to reason as if they were strict, inferring MacLane isomorphims automatically in the background. Together with an external tool for visualising and editing string diagrams, this make it possible to perform rewriting steps in monoidal categories graphically, and to translate them into textual formal proofs which are concise and readable
Adhesive category theory for graph rewriting in Rocq
No full textInternational audienceWe design a Rocq library about adhesive categories, using Hierarchy Builder (HB). It is built around two hierarchies. The first is for categories, with usual categories at the bottom and adhesive categories at the top, with weaker variants of adhesive categories in between. The second is for morphisms (notably isomorphisms, monomorphisms and regular monomorphisms). Each level of these hierarchies is equipped with several interfaces to define instances.We cover basic categorical concepts such as pullbacks and equalizers, as well as results specific to adhesive categories. Using this library, we formalize two central theorems of categorical graph rewriting theory: the Church-Rosser theorem and the concurrency theorem. We provide several instances, including the category of types, the category of finite types, the category of simple graphs and categories of presheaves. We detail the implementation choices we made and report on the usage of HB for this formalization work
Numerical analysis of 3D crack initiation under rolling contact fatigue in polycrystals with subsurface inclusions and surface dents
No full textInternational audienceRolling contact fatigue (RCF) remains a critical challenge in the design and longevity of mechanical components such as rolling element bearings, gears, and railway tracks. This study presents a novel numerical model to simulate crack initiation under RCF conditions, focusing on both subsurface and surface initiation mechanisms. The model incorporates polycrystalline microstructures generated with Voronoi tessellations, and random crystallographic orientations. Contact stresses are computed using the highly efficient Green-FFT method, enabling high resolution 3D analysis. The Tanaka–Mura fatigue crack initiation model is used. This model is grounded in the physical mechanism of dislocation energy accumulation within slip bands, with initiation occurring when the accumulated energy reaches a critical fracture energy. Slip band geometry is determined based on grain orientation and geometry. The model is applied to two scenarios: subsurface initiation near an inclusion and surface initiation near a dent. By simulating multiple microstructures, statistical analyses of crack position, orientation, and initiation life are conducted. Key results include the influence of inclusion stiffness on initiation sites, the alignment of cracks near inclusions, and the preferential initiation of cracks near dents. Additionally, increasing Hertz pressure reduces mean initiation life and decreases its variability, while the number of grains within the stress concentration volume significantly affect initiation life dispersion. The study highlights the necessity of 3D modeling to capture the complex, out-of-plane crack initiation behaviors that cannot be adequately represented in 2D simulations
Within‐Host Environmental Heterogeneity Is Associated With Phenotypic but Not Genomic Diversity in Wolbachia Endosymbionts
No full textInternational audienceHosts represent complex environments where different tissues may act as distinct ecological niches, imposing different constraints that may shape parasite ecology and evolution. Such within‐host heterogeneity can generate phenotypic diversity with consequences for virulence and transmission. Our aim was to determine whether the constraints associated with infecting different host tissues lead to the coexistence of multiple parasite sub‐populations with distinct phenotypes. We tested this hypothesis using the widespread bacterial endosymbiont Wolbachia . We injected bacteria isolated from three tissues of the common pill‐bug into uninfected individuals and tracked temporal changes in Wolbachia load in the recipient host tissues, as well as the virulence associated with each bacterial source. Our results show that colonisation success depends on the tissue of origin of the injected Wolbachia . Genome resequencing did not detect any genetic variation associated with variation in bacterial replication rate, which thus likely results from phenotypic plasticity. Indeed, no recurrent tissue‐specific variants were detected, and our conservative filtering pipeline retained only one substitution and one gene conversion event. These findings highlight the genomic stability of Wolbachia across host environments while demonstrating that within‐host diversification can occur without genetic divergence. More broadly, they underscore how microenvironmental variation within hosts can shape parasite ecology
Patch-based Representation and Learning for Efficient Deformation Modeling
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Multiresolution Adaptive Block-Coordinate Forward-Backward for Image Reconstruction
No full textClassical first-order optimization methods for imaging inverse problems scale poorly with image resolution. Wavelet based multilevel strategies can accelerate convergence under strong blur, but their fixed coarse-to-fine schedules lose effectiveness in moderate-blur or noise-dominated regimes.In this work, we propose an adaptive multiresolution block coordinate Forward-Backward algorithm for image restoration. Multiresolution block selection is driven by the local magnitude of the proximal update via a stochastic non-smooth Gauss-Southwell rule applied to the wavelet decomposition of the image. This adaptive selection strategy dynamically balances updates across scales, emphasizing coarse or fine blocks according to the degradation regime. As a result, the proposed method automatically adapts to varying blur and noise levels without relying on a predefined hierarchical update scheme