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An efficient construction of Raz's two-source randomness extractor with improved parameters
No full textRandomness extractors are algorithms that distill weak random sources into near-perfect random numbers. Two-source extractors enable this distillation process by combining two independent weak random sources. Raz's extractor (STOC '05) was the first to achieve this in a setting where one source has linear min-entropy (i.e., proportional to its length), while the other has only logarithmic min-entropy in its length. However, Raz's original construction is impractical due to a polynomial computation time of at least degree 4. Our work solves this problem by presenting an improved version of Raz's extractor with quasi-linear computation time, as well as a new analytic theorem with reduced entropy requirements. We provide comprehensive analytical and numerical comparisons of our construction with others in the literature, and we derive strong and quantum-proof versions of our efficient Raz extractor. Additionally, we offer an easy-to-use, open-source code implementation of the extractor and a numerical parameter calculation module
An equation for the kinetic energy balance in homogeneous turbulence
No full textInternational audienceWe derive a two-equation model for the energy balance in statistically homogeneous turbulence. The present formulation is expressed in terms of the energy flux, unlike the classical approach, where the dissipation rate appears in the kinetic energy equation. This enables a unified description of both forced and decaying turbulence with a single set of model constants. The model also captures the time lag between the evolution of the kinetic energy and the dissipation rate. Reformulating the system as an equation for the dissipation rate further clarifies how non-equilibrium effects can be incorporated into existing turbulence models
Les structures baptismales en Gaule hors la ville (villae, castra) : retour sur les problèmes d’identification des structures et des contextes d’implantation (Ve-VIIe siècles)
No full textInternational audienceCet article s’intéresse aux structures baptismales implantées hors du cadre urbain en Gaule entre le Ve et le VIIe siècle, notamment dans des villae ou des castra. Il interroge les difficultés d’identification archéologique de ces édifices ainsi que les incertitudes pesant sur leur statut, leur fonction et leur relation à l’épiscopat. Loin d’être marginales, ces fondations témoignent d’une dynamique chrétienne enracinée dans des réalités locales, souvent en lien avec des réseaux aristocratiques ou des noyaux d’habitat secondaire. La diversité des contextes invite à dépasser les oppositions entre ville et campagne, et à repenser les modalités d’implantation et de diffusion du christianisme. L’article souligne enfin la nécessité d’éclairer les formes d’encadrement religieux de ces sanctuaires, avant la normalisation conciliaire du VIe siècle, et appelle à de nouvelles enquêtes croisant données archéologiques, topographiques et contextuelles
Evaluation of functional deficits using the Ankle‐GO™ score before and after arthroscopic anatomic lateral ankle ligament reconstruction among patients suffering from chronic ankle instability
No full textInternational audienceAbstract Purpose To evaluate the evolution of ankle deficits in patients suffering from chronic ankle instability (CAI) following an arthroscopic anatomic lateral ankle ligament reconstruction (AALALR) based on Ankle‐GO™. Methods This prospective cohort (2022–2023) included patients suffering from CAI who underwent an AALALR. The primary outcome was the evolution of ankle deficits at 5 months postsurgery, assessed using the Ankle‐GO™, which includes the modified Star Excursion Balance Test (mSEBT), Figure‐of‐8 Test (F8T), Side Hop Test (SHT) and Single‐Leg Stance Test (SLS), the Foot and Ankle Ability Measure (Foot and Ankle Ability Measure—Activity of Daily Living [FAAM‐ADL] and Foot and Ankle Ability Measure—Sport [FAAM‐Sport]) and the Ankle Ligament Reconstruction–Return to Sport after Injury (ALR‐RSI) scale. Secondary outcome was the return to sports (RTS). Factors influencing lower postoperative Ankle‐GO TM were evaluated. Results Fifty patients (mean age 29.8 ± 11.1 years) were included. The Ankle‐GO™ score increased significantly from 8.2 ± 4.7 to 13.9 ± 5.4 at 5 months postoperatively ( p < 0.01; r = 0.80). Among the individual components, ALR‐RSI showed the greatest improvement, rising from 28.0% to 69.0% ( p < 0.01; r = 0.86), followed by FAAM‐Sport (56.5%–80.1%; p < 0.01; r = 0.71). The FAAM‐ADL score increased significantly from 82.4% to 91.8% ( p < 0.01). The F8T did not improve significantly ( p > 0.05). At 5 months, 35 patients (70.0%) had returned to sport, although only 11 (31.4%) had resumed at their pre‐injury level. Preoperative Ankle‐GO™ was lower in patients not returning to sport (6.4 vs. 9.1; p = 0.04). Conclusion This short‐term study confirmed that the Ankle‐GO™ score effectively tracks recovery following AALALR. The score reflects improvements in both static and dynamic stability as well as psychological readiness. Additionally, preoperative scores were found to predict a patient's ability to RTS. Level of Evidence Level II, prospective cohort study
History and geochemical signatures of hydrothermally silicified volcanic and sedimentary rocks from the Paleoarchean (3.5-3.2 Ga) Barberton Greenstone Belt
No full textco-auteur étrangerInternational audienceSeafloor-derived silicified volcanic and sedimentary rocks provide unique records ofhydrothermal systems that operated at the top of the Paleoarchean submerged crust. Basedon petrographic, thermometric, and geochemical analyses, we distinguish the signaturesof Paleoarchean hydrothermal activity from those due to subsequent metamorphismand weathering in silicified volcanic and sedimentary rocks sampled from the3.5–3.2 GaBarberton Greenstone Belt. Measured138La-138Ce and147Sm-143Nd isotopic compositionsindicate that weathering by post-Archean oxidised fluids modified LREE abundances insamples displaying Ce anomalies. Raman spectroscopy of carbonaceous material, chloritethermometry and oxygen isotope thermometry provide evidence for mineralogical resettingby regional metamorphism at∼350±50°C, which arguably did not modify the bulk-rockgeochemistry. Oxygen isotope fractionation in a quartz-carbonate assemblage preservedfrom subsequent resetting provides a minimum temperature of∼110±50°Cinterpreted asthe highest possible temperature of the Paleoarchean silicifying hydrothermal fluids. Y/Hoand Zr/Hf ratios are chondritic in silicified volcanic and clastic sedimentary rocks, whichdifferentiates them from Archean orthochemical cherts with suprachondritic Y/Ho and Zr/Hfratios. Finally, silicified volcanic rocks that are free of Ce anomalies (mostly unweatheredby oxidising fluids) display slightly lower Sm/Nd ratios and more variable Lu/Hf ratios thannon-silicified counterparts, which we ascribe to differential REE mobilisation by silicifyinghydrothermal fluids. The modification of Sm/Nd and Lu/Hf ratios during Paleoarcheanhydrothermal activity should be integrated in future Sm-Nd and Lu-Hf isotopic investigationsof hydrothermal inputs to Archean ocean chemistry and of recycled seafloor-derived rock
Computing the degreewidth of a digraph is hard
No full textGiven a digraph, an ordering of its vertices defines a backedge graph, namely the undirected graph whose edges correspond to the arcs pointing backwards with respect to the order. The degreewidth of a digraph is the minimum over all ordering of the maximum degree of the backedge graph. We answer an open question by Keeney and Lokshtanov [WG 2024], proving that it is NP-hard to determine whether an oriented graph has degreewidth at most 1, which settles the last open case for oriented graphs. We complement this result with a general discussion on parameters defined using backedge graphs and their relations to classical parameters
Real-time redesign of public transport lines under fluctuating traffic conditions
No full textPublic Transport (PT) lines are traditionally designed to optimize performance under nominal traffic conditions. In practice, however, operating conditions frequently deviate from the nominal ones, leading to substantial performance deterioration. Existing adaptation mechanisms typically rely on corrective and reactive interventions, such as stop-skipping, which prove insufficient under large or recurrent traffic fluctuations. In such contexts, incremental adjustments are inadequate, and a structural redesign of the network becomes necessary. This paper introduces a real-time optimization method for proactively redesigning PT networks to maintain high levels of user- and operator-oriented performance under pronounced traffic fluctuations. We adopt a predict-then-optimize paradigm in which PT lines are reconfigured based on predicted traffic conditions via an algorithm based on the Non-dominated Sorting Genetic Algorithm III (NSGA-III). To ensure operational implementability, we explicitly constrain structural deviations by enforcing high Jaccard similarity between the baseline and redesigned networks, thereby preserving network continuityand limiting operational disruption. To account for the effect of prediction inaccuracies on redesign quality, we construct a statistical model of the errors made by a well-established deep learning-based prediction model (Diffusion Convolutional Recurrent Neural Network) trained on real-world data. Computational results on Mandl’s benchmark network, under high traffic fluctuations, show that at least 77.9% of OD pairs experience travel time reductions of at least 20%, alongside operational cost savings of up to 37%, while retaining 79% of the original network structure. Experiments on the large-scale Beijing network further demonstrate average travel time improvements of up to 20.5% and operational cost reductions of 15.6%, while maintaining more than 60% route overlap with the incumbent configuration. These findings demonstrate that proactive, prediction-driven redesign can substantially improve performance, compared to current inflexible PT designs, thereby motivating a transition from current static planning paradigms toward continuous and adaptive PT network design
A day in the life of an aged cat – Environment of old domestic cats and welfare implications
No full textInternational audienc
Early Recognition and Management of Severe Sodium Nitrite Intoxication: A Case Report Emphasizing Prehospital Administration of Methylene Blue
No full textInternational audienceWe present the case of an 18-year-old male who was found unresponsive at home with profound cyanosis and shock. On-site suspicion of methemoglobinemia -suggested by chocolate-colored blood1 and refractory hypoxemia despite 100% oxygen - prompted early administration of methylene blue by emergency medical services. A second dose of methylene blue was given after patient's admission at the emergency department, resulting in a marked reduction in methemoglobin levels and rapid clinical improvement. This case highlights the importance of early recognition of toxicologic emergencies and timely administration of antidotes, including in the prehospital setting. It also underscores the need for ongoing education and training of health care professionals - especially first responders - on the identification and management of acute intoxications
An inverse problem resolution for 3D particle tracking using event-based vision
No full textParticle tracking in fluid systems is fundamental for the characterization of complex flow dynamics, but current methods are constrained by temporal and spatial resolution of conventional frame-based cameras. This paper proposes the application of the emerging event-based technology to reconstruct a 3D trajectory from 2D projections acquired by event-based cameras. Building on the pinhole camera model, we reformulate the well-established relation between the 2D projections and 3D estimate. This allows us to define a convex data-fidelity term, and a reconstruction procedure based on the minimization of a penalized least-squares functional. Experimental results show that this approach enables the reconstruction of a 3D trajectory with high accuracy. This method opens new perspectives for the analysis of complex flows in fluid systems