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Monitoring SARS-CoV-2 variants with complementary surveillance systems: risk evaluation of the Omicron JN.1 variant in France, August 2023 to January 2024
No full textInternational audienceBackground Early detection and characterisation of SARS-CoV-2 variants have been and continue to be essential for assessing their public health impact. In August 2023, Santé publique France implemented enhanced surveillance for BA.2.86 and sub-lineage JN.1 because of their genetic divergence from other variants and increased prevalence. Aim To detail how combining epidemiological and laboratory data sources, targeted investigations and modelling enabled comprehensive characterisation of sub-lineage JN.1. Methods Data were collected from epidemiological investigations using a standardised questionnaire and from routine and novel (RELAB network) surveillance systems. JN.1 cases were compared with cases infected with previously circulating variants, such as EG.5, BA.4/BA.5 and other BA.2.86 sub-lineages. The growth rate and doubling time of JN.1 were estimated. Results JN.1 was first detected in September 2023 in the Île-de-France region, France, and spread widely across the country. By late November, doubling time was estimated to be 8.6 to 26.4 days depending on the region. For all data sources, cases infected by JN.1 showed similar demographics, rates of hospitalisation and RT-PCR cycle threshold values compared with those infected by previous variants. JN.1 cases also had older median age (54 years; 40–71 vs 47 years; 30–59), more frequent reports of feverish feeling and less frequent cough or nausea compared with BA.4/BA.5 cases. JN.1 cases had significantly higher frequency of anosmia compared with other BA.2.86 cases. Conclusion Combining different data sources played a key role in detecting emerging variant JN.1, for which no evidence of increased public health impact was found despite its genetic divergence
Walking Economy and Preferred Speed in Old and Very Old Men
No full textInternational audiencePurpose With aging, the decline in preferred walking speed (PWS), influenced by the increased energy cost of walking (CoW), is a key predictor of morbidity. However, the determinants associated with PWS and CoW remain poorly understood, especially after 80 yr old. The aim of the study was to characterize the amplitude and mechanisms of age-related decline in CoW and PWS in old (OM) and very old (VOM) men. Methods Thirty-nine young men (YM; 22.1 ± 3.4 yr), 34 OM (71.7 ± 4.1 yr), and 23 VOM (85.8 ± 2.7 yr) performed aerobic, neuromuscular, and gait assessments. Net CoW was measured on a treadmill. Physical activity (PA) was evaluated by questionnaire and accelerometry. Results Net CoW was 32% ( P < 0.001), 19% ( P < 0.01), and 26% ( P < 0.001) higher in VOM compared with OM for 1.11 m·s −1 , 1.67 m·s −1 , and PWS. Net CoW was also 27% ( P < 0.001), 26% ( P < 0.01), and 29% ( P < 0.001) higher in OM compared with YM at these speeds. Linear regression stratified by age showed that net CoW at PWS was associated with step frequency ( r = 0.79; P < 0.001) for OM and with both coefficient of variation of stride mean time ( r = 0.48; P < 0.05) and maximal strength of knee extensors ( r = −0.54; P < 0.05) for VOM. The same analysis revealed that PWS was correlated with net CoW ( r = −0.56; P < 0.05) and PA ( r = 0.47; P < 0.05) in VOM. Conclusions The progressive increase in net CoW with age was associated with gait and neuromuscular impairments, particularly after the age of 80 yr. This increase in net CoW was related to a decrease in PWS in VOM, suggesting an adaptation of PWS to compensate for the increase in energy demand. Maintaining a high level of PA may potentially delay the age-related decline in PWS despite an age-related increase in net CoW
7 Octobre : le destin visuel des otages
No full textInternational audienceLes images des crimes du 7 octobre ont suscité, au-delà d’un choc bien compréhensible, de nombreux débats : fallait-il montrer l’horreur que les terroristes du Hamas ont cherché à filmer et à diffuser ? Emmanuel Taïeb interroge ici le destin de ces images et les usages politiques qui en ont été fait, mettant en évidence leur réversibilité et le risque qu’il y aurait à les invisibiliser
Foi et (anti-)Lumières : Controverses autour de l’Aufklärung dans la prédication et dans la presse viennoise, de 1770 à 1800
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Nonlinear partial differential equations in neuroscience: from modelling to mathematical theory
No full textMany systems of partial differential equations have been proposed as simplified representations of complex collective behaviours in large networks of neurons. In this survey, we briefly discuss their derivations and then review the mathematical methods developed to handle the unique features of these models, which are often nonlinear and non-local. The first part focuses on parabolic Fokker-Planck equations: the Nonlinear Noisy Leaky Integrate and Fire neuron model, stochastic neural fields in PDE form with applications to grid cells, and rate-based models for decision-making. The second part concerns hyperbolic transport equations, namely the model of the Time Elapsed since the last discharge and the jump-based Leaky Integrate and Fire model. The last part covers some kinetic mesoscopic models, with particular attention to the kinetic Voltage-Conductance model and FitzHugh-Nagumo kinetic Fokker-Planck systems
Jamblique critique littéraire: mise en perspective de son éloge des qualités littéraires et scientifiques des hypomnēmata pythagoriciens
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Quantization-Based Latin Hypercube Sampling for Dependent Inputs With an Application to Sensitivity Analysis of Environmental Models
No full textInternational audienceNumerical models are essential for comprehending intricate physical phenomena in different domains. To handle their complexity, sensitivity analysis, particularly screening, is crucial for identifying influential input parameters. Kernel-based methods, such as the Hilbert Schmidt Independence Criterion (HSIC), are valuable for analyzing dependencies between inputs and outputs. Implementing HSIC requires data from the original model, which leads to the need of efficient sampling strategies to limit the number of costly numerical simulations. While, for independent input variables, existing sampling methods like Latin Hypercube Sampling (LHS) are effective to estimate HSIC with reduced variance, incorporating dependence is challenging. This paper introduces a novel LHS variant, quantization-based LHS (QLHS), which leverages Voronoi vector quantization to address dependent inputs. The method provides good coverage of the range of variations in the input variables. The paper outlines expectation estimators based on QLHS in various dependency settings, demonstrating their unbiasedness. The method is applied on several models of growing complexities, first on simple examples to illustrate the theory, then on more complex environmental hydrological models, when the dependence is known or not, and with more and more interactive processes and factors. The last application is on the digital twin of a French vineyard catchment (Beaujolais region) to design a vegetative filter strip and reduce water, sediment and pesticide transfers from the fields to the river. QLHS is used to compute HSIC measures and independence tests, demonstrating its usefulness, especially in the context of complex models
Auschwitz. Espaces et lieux d'un système concentrationnaire.
No full textSymbole de l'horreur concentrationnaire nazie, le site historique d'Auschwitz s'avère difficile à appréhender par les visiteurs, comme le remarquent souvent les accompagnateurs lors des visites pédagogiques. Les spatialités du site sont le produit de logiques relevant de temporalités et d'échelles multiples. Notre hypothèse est qu’une cartographie dynamique peut aider à rendre compte de la complexité du site et de son évolution entre 1940 et 1945, et ainsi à leverles confusions et les incompréhensions.https://storymaps.arcgis.com/stories/41e07eec280e4f6f9ed8f26105f48a4
«La théologie scientia quasi subalternata au XIIIe siècle. À propos du livre Le désir de vérité d’Olivier Boulnois»
No full textPre-publicationInternational audienceÀ partir du livre d'O. Boulnois, "Le désir de vérité", j'analyse d'abord comment la théologie, discours sur le divin et su dieu, entre le XIIe et le XIIIe siècle, manifeste l'exigence de se structurer en savoir, face aux disciplines philosophiques et sur leur modèle. Ensuite, j'étudie comment la notion de théologie entendue comme 'scientia quasi subalternata', à la manière des sciences de l'Organon d'Aristote, a évolué, entre 1250 et les années 1280: par une interprétation de l'Organon, apparemment plus fidèle à l'intention d'Aristote, certains théologiens des années 1280 refusent d'appliquer à la théologie la notion aristotélicienne de science, pour construire un savoir théologique fondé exclusivement sur la foi révélée et indépendant des exigences scientifiques de l'Organon