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Observation of charge-parity symmetry breaking in baryon decays
No full textInternational audienceThe Standard Model of particle physics, the theory of particles and interactions at the smallest scale, predicts that matter and antimatter interact differently due to violation of the combined symmetry of charge conjugation () and parity (). Charge conjugation transforms particles into their antimatter particles, while the parity transformation inverts spatial coordinates. This prediction applies to both mesons, which consist of a quark and an antiquark, and baryons, which are composed of three quarks. However, despite having been discovered in various meson decays, violation has yet to be observed in baryons, the type of matter that makes up the observable Universe. This article reports a study of the decay of the beauty baryon to the final state and its -conjugated process, using data collected by the LHCb (Large Hadron Collider beauty) experiment at CERN. The results reveal significant asymmetries between the decay rates of the baryon and its -conjugated antibaryon, marking the first observation of violation in baryon decays, thus demonstrating the different behaviour of baryons and antibaryons. In the Standard Model, violation arises from the Cabibbo-Kobayashi-Maskawa mechanism, while new forces or particles beyond the Standard Model could provide additional contributions. This discovery opens a new path to search for physics beyond the Standard Model
Off-Piste Skiing Demand Patterns and Climate Change Adaptation Pathways in La Grave, France
No full textInternational audienceOff-piste skiing is an adventurous niche segment of ski tourism that is gaining in popularity. However, its demand dynamics remain unclear. This study aimed to elucidate daily off-piste skiing demand patterns by developing a regression model for La Grave, located in the French Alps, where all visitors engage in off-piste skiing. We found that the amount of fresh snow positively influenced skier visits and forecasted avalanche risk did not affect skier visits. Vacation periods did not positively influence skier visits, whereas the post-COVID period has had a negative effect. We also discuss the impact of climate change and adaptation strategies in the area. La Grave depends heavily on off-piste skiing. Because one of the purposes of this activity is to ski on fresh natural snow, it cannot rely on snow management practices such as grooming and snowmaking, which are widespread adaptations in conventional ski areas. The winter business model in La Grave is expected to face further challenges in the future because of climate change. In addition, both a new development plan and opposition movements have emerged. La Grave appears to be undergoing a transition away from a model heavily dependent on off-piste skiing
Tibial implant varus >3° does not adversely affect outcomes or revision rates in functionally aligned image‐based robotic total knee arthroplasty in a minimum of 2‐year follow‐up
No full textInternational audienceAbstract Purpose Functional alignment (FA) aims to restore knee kinematics by balancing laxities and adapting implant positioning. This study evaluates safety and outcomes of >3° varus tibial positioning in patients with varus deformity undergoing robotic‐assisted total knee arthroplasty (TKA). Methods This retrospective study included 337 patients with varus deformity undergoing robotic‐assisted TKA with FA principles with a minimum of 2‐year follow‐up. Patients were divided into two groups based on tibial varus positioning: ≤3° varus: Group A and >3° varus: Group B. Preoperative and postoperative coronal alignment, implant positioning, and outcomes were assessed using the Knee Society Score (KSS) and the Forgotten Joint Score (FJS) at final follow‐up. The primary outcome was implants' survivorship, and secondary outcomes included complication rates and functional scores. Statistical analyses included Mann–Whitney and Chi‐square tests for group comparisons, Kaplan–Meier survival analysis for implant survivorship, and multivariate regression for key covariates. Results Implant survivorship was 99.4% in Group B over a median follow‐up of 30 months, with one revision due to aseptic loosening and 100% in Group A ( p = 0.36). The overall complication rates were 12.7% in Group A and 10.2% in B ( p = 0.48). The median KSS‐knee and function scores were 94.5 and 90 in Group A and 94 and 90 in B ( p = 0.88 and 0.8, respectively). The final FJS was 82 in Group A and 84 in B ( p = 0.8). No significant differences were observed in postoperative knee range of motion between the two groups. Multivariate regression analysis showed that none of the included covariates were statistically significant predictors of implant failure. Conclusion FA in robotic‐assisted TKA with tibial positioning >3° varus seems to be safe and reliable in patients with varus deformity, demonstrating similar revision rates, implant survivorship, and outcomes compared to the ≤3° tibial varus group. Level of Evidence Level III
Utilisation de l'occulomètre Néon de Pupil Labs pour les nourrissons de 3 à 24 mois
No full textUsing Pupil Labs' Neon eye-tracking module for infants aged 3 to 24 monthsWhile most studies analyzing infant visual attention use methods varying from annotations of videos from head-mounted cameras [1], [2], [4], [5] to fixed screen-based eyetracking setups [6], [7], [8], [9], [10], increasing interest has been shown towards solutions that would pair the precision of eyetracking with the free mobility offered by video annotation. This would allow infant research to gather high-quality visual attention data in naturalistic situations, which might yield results more representative of real-world infant environments [11]. For this purpose, various forms of portable eye-tracking devices have been developed and used to study infant cognition [3], [12], [13], [14], along with frequently time-consuming infant-adapted calibration procedures. Recently, the advent of calibration-free lightweight wearable eye-tracking systems developed by Pupil Labs © is offering new and simpler ways to study infant visual attention with the advantages of deeplearning calibration and miniaturization. However, despite a wide variety of wearing accessories being offered by the company, no suitable option currently exists for infants younger than 2 years old. In this paper, instructions will be provided to build a new wearing accessory for Pupil Labs' Neon eyetracking module adapted to 3 to 24 months-old infants, along with usage instructions.</div
The Size-Change Principle for Mixed Inductive and Coinductive types
No full textThis paper shows how to use Lee, Jones and Ben Amram's size-change principle to check correctness of arbitrary recursive definitions in an ML / Haskell like programming language with inductive and coinductive types.Naively using the size-change principle to check productivity and termination is straightforward but unsound when inductive and coinductive types are nested. We can however adapt the size-change principle to check ``totality'', which corresponds exactly to correctness with respect to the corresponding (co)inductive type
Probing new forces with nuclear-clock quintessometers
No full textInternational audienceClocks based on nuclear isomer transitions promise exceptional stability and precision. The low transition energy of the Thorium-229 isomer makes it an ideal candidate, as it may be excited by a vacuum-ultraviolet laser and is highly sensitive to subtle interactions. This enables the development of powerful tools for probing new forces, which we call quintessometers. In this work, we demonstrate the potential of nuclear clocks, particularly solid-state variants, to surpass existing limits on scalar field couplings, exceeding the sensitivity of current fifth-force searches at submicron distances and significantly improving equivalence-principle tests at kilometer scales and beyond. Additionally, we highlight the capability of transportable nuclear clocks to detect scalar interactions at distances beyond km, complementing space-based missions
Diagnosis and data analysis of aging patterns for second life applications of electric vehicle batterie
No full textInternational audienceRapid and accurate diagnosis of the state of health of electric vehicle batteries with a view to their second-life applications still remains a difficult problem that needs to be resolved. In a context of upcoming pressure for the battery market, driven by economic, environmental or practical issues, batteries second life applications emerge as a solution. From modules having undergone a first life as an electric vehicle, we simulated three different possible second life applications. Two batches of aged prismatic modules (50 Ah) with different first lives were considered, characterized, and randomly spread into three aging groups. Solar-type profile simulates renewable energy storage, with a charge during day and discharge during night. UPS (Uninterruptible Power Supply) protocol consists of applying constant voltage at 100 % state of charge. Lastly, classical storage protocol simulates calendar aging. Check-ups are made on a regular basis by cycling at low C-rate and making Electrochemical Impedance Spectroscopy (EIS) measurements at different state of charge. Different tools are used for data analysis such as Equivalent Circuit Models, Incremental Capacity Analysis (ICA), or projection algorithms.Primary check-ups of aging protocols point out three different behaviours independent from first life. Concerning the solar-type profile: although signs of aging are observable in ICA data, most cells showed a stabilization in terms of performance, and even a resistance decrease with a gain of capacity for some of them. As regards the UPS protocol, cells showed an expected behaviour: resistance increase and capacity loss. The same behaviour occurs for the classical storage protocol, but in a slower manner. For each protocol, advanced data analysis of ICA and EIS highlight different degradation modes and identify defective cells. These promising results could provide a better insight into the remaining useful life of a battery (RUL) in the context of a given second-life application. Further work will be the continuation of aging tests, the exploitation of dimensionality reduction and descriptive statistical analysis for diagnostic purposes
Club des Entreprises USMB: présentation du Département Communication Hypermédia et de nos dispositifs numériques
No full textInternational audienceJeudi 13 mars, avec Marc Veyrat, nous avons eu le plaisir d’intervenir auprès du Club des Entreprises de l'Université Savoie Mont Blanc, à l’invitation de Nicolas Borghèse. Nous avons présenté les spécificités du Département Communication Hypermédia, notamment à travers des projets en recherche-création et en méthodologie visuelle, questionnant les liens entre territoire, data et création. L’occasion de partager notre pédagogie 100 % Approche par Compétences (APC), illustrant la manière dont elle structure les apprentissages autour de projets concrets, critiques et créatifs
Montages assurantiels d’anticipation des risques liés aux installations photovoltaïques sur des biens des collectivités locales
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Recent earthquakes on unmapped faults highlight hidden seismic hazards within the Golden Triangle region of Laos, Thailand and Myanmar
No full textInternational audienceIn the past decade, six 5.5 earthquakes struck the mountainous Golden Triangle region (Laos, Thailand, Myanmar) of the southeast India–Eurasia collision zone. The largest of them, the 2019 6.2 Sainyabuli earthquake in western Laos, shook river communities, dams and a UNESCO World Heritage Site, prompting a need to understand regional earthquake potential. We used Interferometric Synthetic Aperture Radar (InSAR) data and modelling to solve for the 2019 main shock source parameters, revealing right-lateral strike-slip along a 24 km-long NNW-trending fault which has limited topographic expression and was previously unmapped. InSAR modelling of its largest ( 5.5) aftershock in 2021 revealed a 7 km-long splay fault, also previously unrecognized. The 2022 5.9 Keng Tung earthquake in the northern Golden Triangle also ruptured an unknown, NW-trending right-lateral fault conjugate to longer, NE-trending faults nearby. Collectively, this shows that the region contains faults which are little evident in global digital topography and/or obscured by vegetation but long enough to generate sizeable earthquakes that should be accounted for in seismic hazard assessments. We relocated well-recorded aftershocks and other background seismicity (1978–2023) from across the Golden Triangle using the mloc software. Calibrated hypocentres span focal depths of 5–24 km and are distributed away from the main InSAR-modelled fault traces, another indication of fault structural immaturity. For the three 2019–2022 InSAR-constrained events, we also obtained moment tensor solutions from regional seismic waveform inversion. InSAR-derived peak slip depths and seismological centroid depths are mostly shallow (3–5 km), while focal depths are generally located in areas of low coseismic slip near the bottom of InSAR model faults. More broadly, we estimate a regional seismogenic thickness of 17 km (the 90 seismicity cut-off depth), a crucial parameter for seismic hazard calculations and building codes. Our integration of remote-sensing and seismologic analyses could be a blueprint for assessing earthquake potential of other regions with sparse instrumentation and limited topographic fault expression