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Euclid: An emulator for baryonic effects on the matter bispectrum
No full textInternational audienceThe Euclid mission and other next-generation large-scale structure surveys will enable high-precision measurements of the cosmic matter distribution. Understanding the impact of baryonic processes such as star formation and AGN feedback on matter clustering is crucial to ensure precise and unbiased cosmological inference. Most theoretical models of baryonic effects to date focus on two-point statistics, neglecting higher-order contributions. This work develops a fast and accurate emulator for baryonic effects on the matter bispectrum, a key non-Gaussian statistic in the nonlinear regime. We employ high-resolution -body simulations from the BACCO suite and apply a combination of cutting-edge techniques such as cosmology scaling and baryonification to efficiently span a large cosmological and astrophysical parameter space. A deep neural network is trained to emulate baryonic effects on the matter bispectrum measured in simulations, capturing modifications across various scales and redshifts relevant to Euclid. We validate the emulator accuracy and robustness using an analysis of \Euclid mock data, employing predictions from the state-of-the-art FLAMINGO hydrodynamical simulations. The emulator reproduces baryonic suppression in the bispectrum to better than 2 for the percentile across most triangle configurations for and ensures consistency between cosmological posteriors inferred from second- and third-order weak lensing statistics
Questionner les technologies avec Andrew Feenberg. Perspectives critiques et socio-philosophiques
No full textInternational audienc
Developing and implementing business ecosystem strategies in the legal sector: current situation and prospects in France
No full textInternational audienceSince the beginning of the 2000s, the concept of business ecosystem (BE), which was introduced by James F Moore in the early 1990s, has become a major topic in management (strategy, management of innovation) and economics (Daidj, 2011). BE is now a concept widely used by both the economic press and the academic world to explain why successful companies are those that collaborate with other organizations to significantly improve their performance and competitiveness (Iansiti & Levien, 2004). The application of this concept to the law thus appears promising for understanding how companies collaborate with other geographically close actors in order to develop legal ecosystems that they can, if necessary, mobilise not only to defend their own interests, but also to provide them with the information and legal know-how they need to carry out their national and international activities.From a conceptual and theoretical perspective, the interpretations of BEs may differ according to various scholars providing their own definitions and representations. Moreover, BEs also vary according to the context and the continuous changes in the business environment with digital transformation, the development and adoption of new technologies (such as artificial intelligence, blockchain, data analytics etc.) and the emergence of new players that have a significant impact on value chain and business models. As the notion of BE has been used in various and sometimes competing ways, we have made the choice here to refer mainly to Moore’s academic work in strategic management. This chapter aims at providing some theoretical insights into BEs drawing mainly from Moore’s publications in order to understand the main features and the evolution of this organizational/network form and to attempt to explain its relevance for the legal sector in France. This chapter includes a description of this sector and its main challenges today with the intensification of uberization and the competition between new entrants (technological platforms) and the various incumbent operators
Spectroscopy and complex-time correlations using minimally entangled typical thermal states
No full text15 pages, 15 figuresInternational audienceTensor network states have enjoyed great success in capturing aspects of strong correlation physics. However, obtaining dynamical correlators at nonzero temperatures is generically hard even using these methods. Here, we introduce a practical approach to computing such correlators using minimally entangled typical thermal states (METTS). While our primary method directly computes dynamical correlators of physical operators in real time, we propose extensions where correlations are evaluated in the complex-time plane. The imaginary time component bounds the rate of entanglement growth and strongly alleviates the computational difficulty allowing the study of larger system sizes. To extract the physical correlators, one must take the limit of purely real-time evolution. We present two routes for obtaining this information: (i) via an analytic correlation function in complex time combined with a stochastic analytic continuation method to obtain the real-time limit and (ii) a Hermitian correlation function that asymptotically captures the desired correlation function quantitatively. We show that these numerical techniques capture the finite-temperature dynamics of the Shastry-Sutherland model—a model of interacting spins one-half in two spatial dimensions
Les MICAS pendant les JOP, ou l’usage extraordinaire d’outils routiniers
No full textInternational audienceIf the administrative antiterrorism legal framework remained unchanged during the Olympics and Paralympics, its application by the Home Office services demonstrates that the scope of behavior administratively qualified as “terrorism” has been extended. The Olympics window illustrates that, in a specific context, authorities can apply this legal framework in a way recalling the state of emergency regime operative in 2015-2017. Moreover, the Olympics of 2024 show the expansion attempts of administrative anti-terrorist policy, and suggest future reforms, particularly in the context of the 2030 Winter Olympics in the French Alps.Si le cadre juridique relatif aux MICAS est resté inchangé pendant les Jeux Olympiques et Paralympiques (JOP), son application par les services du ministère de l’Intérieur témoigne d’une extension considérable du champ des comportements pouvant être qualifiés, sur le plan administratif, de « menace terroriste ». La fenêtre olympique démontre ainsi qu’à la faveur d’un contexte particulier, le cadre juridique issu de la normalisation de l’état d’urgence peut être appliqué dans un cadre rappelant la mise en œuvre de ce dernier entre 2015 et 2017. Surtout, cette fenêtre témoigne des tentatives d’extension de la police administrative antiterroriste, et laisse présager de futures réformes, notamment dans le cadre des JOP d’hiver de 2030
Preliminary Results from the IWGSC Wheat Diversity Project: International initiative to unlock bread wheat diversity by sequencing 12 maximally diverse landrace genomes & update RefSeq Chinese Spring
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Améliorer la performance humaine grâce à une vision augmentée
No full textAugmented Vision (AV) is an emerging field that aims to enhance human sight by directly modulating a user's view of the real world. Unlike traditional visual aids such as spectacles or contact lenses that provide static correction, AV systems offer dynamic, real-time modulation of the real world. This capability to actively change the user's view opens up new possibilities for both correcting and augmenting human vision.One of the three most common applications for AV is vision correction. This is particularly relevant for presbyopia, an age-related condition affecting 1.8 billion people worldwide. Conventional solutions, such as progressive glasses or multifocal contact lenses, offer a static compromise with fixed focal zones or averaged focus, respectively. In contrast, AV systems use their inherently dynamic behaviour to address these limitations. For instance, some systems use automatic single focus approaches using focus-tunable lenses to focus at specific depths. However, this approach is limited to applying one optical power across the entire field of view at a time. The alternatives are multifocal systems, which provide granular, spatial control over focus. However, while the concept has been demonstrated, there is a lack of objective evaluation of the imaging quality of such systems.This thesis addresses two primary objectives. The first is to establish a conceptual framework for Augmented Vision by stating a formal definition and a new taxonomy that categorises existing systems by their light modulation method. The second is to address a gap identified by this framework: the lack of multifocal augmented vision systems and the evaluation of their imaging performance.To tackle the challenges of providing multifocal vision, this thesis proposes an optical architecture that combines a phase-only Spatial Light Modulator (SLM) with a Lohmann lens, allowing spatial control of the optical power over the Field Of View (FOV), providing see-through, real-world modulation. We validate the prototype by measuring the Modulation Transfer Function (MTF) for global and multifocal correction, placing objects at various depths and setting the system's focus at them. We use a camera with its focus set to infinity to simulate a presbyopic eye during the measurements. The results confirm that the system can bring objects from multiple depths into focus, demonstrating a higher MTF for each focused plane when the system is active compared to the inactive condition.This thesis provides two primary contributions: (1) a formal conceptual framework for AV systems that identifies the research gap, and (2) a prototype of an optical platform for multifocal vision and its evaluation. This platform serves as foundational technology for exploring a new class of interfaces based on spatially-variant optical power to enhance visual perception and address widespread visual impairments.La vision augmentée (VA) est un domaine émergent qui vise à améliorer la vision humaine en modulant directement la perception qu'a l'utilisateur du monde réel. Contrairement aux aides visuelles traditionnelles telles que les lunettes ou les lentilles de contact qui offrent une correction statique, les systèmes de VA permettent une modulation dynamique et en temps réel du monde réel. Cette capacité à modifier activement la perception de l'utilisateur ouvre de nouvelles possibilités pour corriger et augmenter la vision humaine. L'une des trois applications les plus courantes de la VA est la correction de la vision. Cela est particulièrement pertinent pour la presbytie, une affection liée à l'âge qui touche 1,8 milliard de personnes dans le monde. Les solutions conventionnelles, telles que les lunettes progressives ou les lentilles de contact multifocales, offrent un compromis statique avec des zones focales fixes ou un contraste réduit, respectivement. En revanche, les systèmes VA utilisent leur comportement intrinsèquement dynamique pour pallier ces limites. Par exemple, certains systèmes utilisent des approches à mise au point unique automatique avec des lentilles à mise au point réglable pour faire la mise au point à des profondeurs spécifiques. Cependant, cette approche se limite à l'application d'une seule puissance optique sur l'ensemble du champ de vision à la fois. Les alternatives sont les systèmes multifocaux, qui offrent un contrôle spatial granulaire de la mise au point. Cependant, bien que le concept ait été démontré, il manque une évaluation objective de la qualité d'image de ces systèmes. Cette thèse aborde deux objectifs principaux. Le premier est d'établir un cadre conceptuel pour la vision augmentée en énonçant une définition formelle et une nouvelle taxonomie qui classe les systèmes existants en fonction de leur méthode de modulation de la lumière. Le second est de combler une lacune identifiée par ce cadre : l'absence de systèmes de vision augmentée multifocaux et l'évaluation de leurs performances d'imagerie. Pour relever les défis liés à la vision multifocale, cette thèse propose une architecture optique qui combine un modulateur spatial de lumière (SLM) à phase uniquement avec une lentille de Lohmann, permettant un contrôle spatial de la puissance optique sur le champ de vision et offrant une modulation transparente et réaliste. Nous validons le prototype en mesurant la fonction de transfert de modulation (FTM) pour la correction globale et multifocale, en plaçant des objets à différentes profondeurs et en réglant la mise au point du système sur ceux-ci. Nous utilisons une caméra dont la mise au point est réglée sur l'infini pour simuler un œil presbyte pendant les mesures. Les résultats confirment que le système peut mettre au point des objets à plusieurs profondeurs, démontrant une FTM plus élevée pour chaque plan mis au point lorsque le système est actif par rapport à l'état inactif. Cette thèse apporte deux contributions principales : (1) un cadre conceptuel formel pour les systèmes VA qui identifie les lacunes de la recherche, et (2) un prototype de plateforme optique pour la vision multifocale et son évaluation. Cette plateforme sert de technologie de base pour explorer une nouvelle classe d'interfaces basées sur la puissance optique variable dans l'espace afin d'améliorer la perception visuelle et de remédier aux déficiences visuelles courantes
Assessment of soil erosion over six decades in a long‐term experiment using fallout 137Cs and rusle : a South American case study
No full textInternational audienceSoil erosion remains a major global concern affecting agricultural productivity and land sustainability. This study investigates the magnitude and variability of soil erosion in a long‐term experiment (LTE) established in 1963 in Colonia, Uruguay, aiming to compare the performance of the 137 Cs tracer technique and the RUSLE model across different crop rotations. We hypothesized that pasture inclusion into rotations reduces soil erosion compared to continuous cropping, regardless of the model. Four contrasting LTE treatments were selected: continuous cropping without fertilization, continuous cropping with fertilization, and two crop‐pasture rotations with 33% or 50% time under pasture. Each plot had a size of 25 × 200 m positioned along a hillslope and was sampled at six sampling points along a transect from the hilltop towards the footslope. Soil erosion was assessed using two methods: (1) the 137 Cs technique, estimating net soil redistribution based on deviations from a reference site, and (2) the RUSLE model, calibrated with national agronomic and climatic data. The 137 Cs method showed erosion rates from −73 to +51 Mg ha −1 year −1 , with accumulation at footslopes and highest losses in eroded gullies under unfertilized continuous cropping. RUSLE predicted losses from −1 to −20 Mg ha −1 year −1 , based on sheet erosion assumptions. The comparison was limited to five sampling points where erosion processes were dominant and compatible with RUSLE assumptions. Nevertheless, results confirmed that crop‐pasture rotations substantially reduced erosion and preserved soil over six decades. We conclude that integrating pastures into rotations is an effective erosion control strategy in sloping agricultural systems and helps maintain long‐term productivity
Biological Surfaces in Biomimicry: A Functional Perspective for Biologists
No full textBiological surfaces perform a wide range of functions, from communication to molecular exchange, defense, and movement. These natural interfaces have inspired innovative technologies across fields such as materials science, robotics, and medicine. This review examines how the structural and functional properties of biological surfaces inform the design of advanced biomimetic materials. We explore communication mechanisms like directional reflection and electrochemical signaling, as well as exchange systems such as aquaporins and extracellular vesicles, which have influenced developments in sensing, filtration, and drug delivery. Defensive strategies, including camouflage, antimicrobial textures, and dynamic barriers, offer models for protective coatings and responsive materials. In the context of movement, we highlight drag-reducing and adhesive surfaces that have led to advances in robotics, textiles, and transport. By analyzing these biological systems through a mechanistic lens, we identify key design principles that support the development of multifunctional, adaptive surfaces. This review provides a framework for translating biological insights into sustainable and high-performance technologies
Prenatal ultrasound diagnosis of fetal upper gastrointestinal bleeding in a monochorionic twin pregnancy: a case report
No full textInternational audienceBackground: Fetal upper gastrointestinal bleeding (UGIB) is an exceptionally rare condition. We report a case of antenatally detected UGIB in a monochorionic diamniotic twin pregnancy, emphasizing key ultrasound features that enabled timely delivery and a favorable neonatal outcome.Case presentation: A 23-year-old woman with a monochorionic diamniotic twin pregnancy complicated by Stage II twin-to-twin transfusion syndrome (TTTS) underwent fetoscopic laser ablation at 23 + 1 weeks. At 33 + 5 weeks’ gestation, routine ultrasound revealed marked gastric and intestinal dilatation with echogenic intraluminal material and echogenic amniotic fluid in the recipient twin, along with elevated middle cerebral artery (MCA) peak systolic velocity (1.53 MoM) suggesting fetal anemia. An emergency cesarean section was performed. The neonate, born in bloody amniotic fluid, presented with hemorrhagic shock due to hemorrhagic gastritis confirmed by endoscopy. After intensive resuscitation, the infant recovered fully and was discharged on Day 23.Conclusion: The coexistence of echogenic bowel content, echogenic amniotic fluid, and increased MCA Doppler should alert clinicians to possible in-utero gastrointestinal bleeding. Early recognition within standardized high-risk pregnancy surveillance protocols may allow life-saving intervention