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An intense peak of paraglacial dismantlement of mountain slopes: Insights from dating and volume quantification of rock-slope failure deposits in the Icelandic Westfjords (Dýrafjörður and Önundarfjörður)
No full textInternational audienceParaglacial rock slope failures (RSFs) are prominent processes of landscape evolution in deglaciated terrains, such as the Westfjords of Iceland. This study aims to provide chronological and volumetric data on RSF deposits in the Dýrafjörður and Önundarfjörður fjords, in order to document the magnitude, duration, and geomorphic impact of the intense peak of Early and Middle Holocene paraglacial denudation. By refining the timing of a paraglacial signal, this work contributes to a better understanding of sedimentary production and landscape evolution during the Holocene.A total of 17 RSFs was studied, described and mapped using the Schmidt-hammer exposure-age dating method, calibrated with radiocarbon dating. Surficial block morphometry and volumetric estimates of RSF deposits were derived from field measurements, orthophotography, and high-resolution digital elevation models.RSF ages are concentrated in the Early to Middle Holocene. The vast majority of this activity occurred between 12 and 6 cal. ka BP. During this 6000-year interval, ~83 million m3 of debris were deposited, which accounts for approximately 90% of the total volume (~92.5 M m3) from all 17 RSF sites. This indicates a primary paraglacial adjustment phase characterized by high sediment delivery efficiency. Slope reactivations occurred over periods up to 3400 years, with superimpositions of deposits: these are multi-phased RSFs.Finally, a significant lag of approximately 3000 years is observed between the deglaciation (~10.2 cal. ka BP) and the peak in rock-slope failure activity (8–6 cal. ka BP), which coincides with the Holocene Thermal Maximum climax in Iceland (8.6–5.2 cal. ka BP). The subsequent cessation of major RSFs activity after ~4 cal. ka BP marks the transition to a stable, non-glacial equilibrium
Impaired theory of mind in Parkinson’s disease: A systematic review of etiological debates
No full textInternational audienc
Éduquer l'attention des élèves grâce au programme ATOLE : évaluations et présentation du projet EvATOLE
No full textCe manuscrit présente le programme ATOLE (Apprendre à être attentif, à l’école) et les résultats de deux dispositifs d’évaluation visant à étudier son impact sur l’attention des élèves. ATOLE est un programme d’éducation de l’attention fondé sur des résultats établis en neurosciences cognitives et en sciences de l’éducation, visant à développer chez les élèves une meilleure compréhension et régulation de leur attention dans le contexte ordinaire de la classe.Une première étude conduite en 2016–2017 a évalué les effets d’ATOLE sur la stabilité attentionnelle d’élèves du primaire et du collège à l’aide d’un test informatisé bref (BLAST). Les résultats montrent des améliorations significatives de la stabilité attentionnelle dans plusieurs classes ATOLE, absentes dans les classes contrôle, bien que les analyses globales ajustées indiquent des effets hétérogènes et dépendants du niveau initial des élèves.Ces résultats ont conduit au projet EvATOLE, une évaluation à plus grande échelle intégrant des outils plus écologiques, des mesures quantitatives et qualitatives, et un accompagnement pédagogique structuré. Les données suggèrent des effets positifs du programme sur la régulation attentionnelle, la métacognition des élèves et certaines pratiques enseignantes. L’ensemble de ces travaux souligne l’intérêt d’une éducation explicite de l’attention, tout en mettant en évidence l’importance du temps long et du contexte pédagogique pour en maximiser les effets
Gaussian Mixture Model with unknown diagonal covariances via continuous sparse regularization
No full textThis paper addresses the statistical estimation of Gaussian Mixture Models (GMMs) with unknown diagonal covariances from independent and identically distributed samples. We employ the Beurling-LASSO (BLASSO), a convex optimization framework that promotes sparsity in the space of measures, to simultaneously estimate the number of components and their parameters. Our main contribution extends the BLASSO methodology to multivariate GMMs with component-specific unknown diagonal covariance matrices. This setting is significantly more flexible than previous approaches, which required known and identical covariances. We establish non-asymptotic recovery guarantees with nearly parametric convergence rates for component means, diagonal covariances, and weights, as well as for density prediction. A key theoretical contribution is the identification of an explicit separation condition on mixture components that enables the construction of non-degenerate dual certificates—essential tools for establishing statistical guarantees for the BLASSO. Our analysis leverages the Fisher-Rao geometry of the statistical model and introduces a novel semi-distance adapted to our framework, providing new insights into the interplay between component separation, parameter space geometry, and achievable statistical recovery
Limitations of Disease X vaccine efficacy and safety clinical trials
No full textAbstract Background In a vaccine clinical trial, the candidate is typically accepted or rejected based on predefined efficacy and safety thresholds. An efficacy threshold is the minimum measured treatment effect deemed statistically significant and clinically relevant. A safety threshold is the maximum number of adverse events deemed acceptable in the vaccine arm of the trial. However, the uncertainties and changing conditions met during the emergence of an unknown infectious disease (Disease X) may hinder such simple approaches. Methods We model the emergence of a Disease X with an SIR (susceptible-infectious-recovered) transmission model. A vaccine is available and the objective is to minimize the total cost over the course of the epidemic, which includes infection, vaccination, and adverse event costs. Uncertainties regarding transmission, vaccine, and cost parameters are represented by prior distributions. We simulate placebo-controlled efficacy and safety trials, and different vaccination policies. Under policies using trial results, the susceptible population is vaccinated if and only if the vaccine candidate passes both the efficacy and safety tests. Results In our baseline scenario and on average over uncertain parameters, using clinical trial outcomes to decide whether to vaccinate the population yields a lower expected total cost compared to indiscriminate emergency vaccination and to no intervention. However, testing both efficacy and safety yields a higher cost compared to testing safety alone. The difference counts in billions of dollars for a population of 10 8 individuals. In our scenario, there is an optimal intermediate safety threshold value that best discriminates vaccine candidates. By contrast, there is no optimal intermediate efficacy threshold value. The incidence difference between the treated and control arms is even a misleading measure of vaccine performance. Conclusions We show with an example that simple threshold-based decision rules may not be appropriate to discriminate candidates in a Disease X vaccine clinical trial. Uncertainties and the disease dynamics need to be fully taken into account, which may require more advanced pattern recognition methods
A Colonial Lens on the High Ground: Imperial Vantage Points in British India and French Indochinese Hill Stations
No full textInternational audienceThis paper focusses on the photographic production within South Asian and Southeast Asian hill stations, established by the British and the French empires in India and in Vietnam, throughout the 19th century. In both countries, hill stations stem from early colonial developments. These remote colonial enclaves were used for a variety of purposes that evolved through time: sanitary, political, military, leisure and commercial (Kennedy 1996). They can be looked at as spatial and symbolic manifestations of imperialism, designed to expand colonial domination to all the corners of the Empire (Mitchell 2002).In order to settle in the hills, the landscape itself had to be domesticated through urban planning, architecture, roads, institutions catering for the new occupants (Sacareau 2007). Soon enough, photography started to be used as a means to document the places, account for their changes, and promote a certain image of the hill stations to a broader audience. Today, vast collections of photographs taken in the hills are kept in colonial archives, be it at the British Library (UK) for India or at the Archives Nationales d’Outre-Mer (France) for Vietnam.Based on a sample of photographs taken between the 1840’s and the 1940’s, this paper will explore the imperial gaze – and visual discourse – on these hill stations. It will interrogate the aesthetics and meanings of these photographs and address the issue of their circulation within and beyond the empires, in order to understand the ways in which photography was used to imprint its gaze and legitimize to the colonisers’ presence.We will examine the tools used to construct this visuality through the photographs that were taken by the colonial settlers on site, for personal and/or propaganda purposes. These photographs were instrumental in defining new aesthetical and scenic functions for these mountains, whose beauty is closely linked to their domination (Zytnicki and Hazdaghli, 2009). The construction of viewpoints, panoramas and hiking trails, and later cable cars, can be explained as panoptic devices serving the construction of a heterotopia (Foucault, 1984). These high angled photographs exploit a symbolic vantage point and enact the domination of these peripheral mountain spaces (Mirzoeff, 2011). They allow contemplating both nature and its colonial reordering, embracing a vast space appropriated to serve racial recreation (Jennings, 2011). Thus, tourism was a consensual and enduring way to not only in the construct, but also in to glorify and promote the imperial gaze
The lithosphere - asthenosphere system seen by surface waves: New insights from radial anisotropy
No full textInternational audienc
Combine anterior cruciate ligament reconstruction and unicompartmental knee arthroplasty with image-based robotic surgery: a current surgical technique
No full textInternational audienceUnicompartmental knee arthroplasty (UKA) is a widely recognized treatment for isolated compartment osteoarthritis (OA). The absence of an intact anterior cruciate ligament (ACL), however, has traditionally been considered a contraindication due to its critical role in maintaining knee stability and joint kinematics. This article aims to provide a detailed description of the surgical technique for UKA with simultaneous ACL reconstruction. It offers a practical guide for surgeons interested in adopting this approach for young, active patients with ACL-deficient and medial or lateral compartment OA, utilizing an image-based robotic platform for both preoperative and intraoperative planning. Indications and contraindications for the combined treatment are also reported. This technique, described through intraoperative images and video, represents a promising, joint-preserving alternative to total knee arthroplasty for appropriately selected patients. This step-by-step approach allows for the assessment of congruence between the bone tunnels and the prosthetic components, enabling a personalized implant positioning
Spatial Distribution of European Grayling Reflects Longitudinal Temperature Patterns in a Swiss River
No full textInternational audienceMost salmonid populations are declining across their entire habitat range, partly because of large‐scale loss of crucial physical habitats. Alterations in river flow and temperature resulting from climate change are likely to further degrade habitat quality, particularly summer thermal conditions experienced by temperature‐sensitive fish species. Understanding how summer thermal conditions control the spatial distribution of ectotherms is thus central to helping project the consequences of climate change and develop management solutions. This study uses snorkelling fish surveys collected over 10 years and airborne thermal infrared (TIR) mapping of surface temperature acquired in 2022 to assess the relationship between European grayling distribution and thermal habitats along a 9‐km long reach of the Allondon River, Switzerland. Results show that all 3 grayling life stages (adults, sub‐adults and juveniles) respond negatively to elevated summer temperature, with distribution patterns highlighting thermal structuring effects on fish populations. The presence of two cooler reaches appears critical to the survival of the Allondon's declining grayling population, while the warmest reach that separates these habitats potentially acts as a thermal barrier during critical summer conditions. These results were used to guide local stakeholders towards short‐term and longer‐term actions to be taken on the river, which include: concerted trans‐national management to protect key upstream tributaries, tree planting to limit summer peak temperature and strategic protection of cold‐water patches that may act as thermal refuges during critical periods
Les déchets et leurs usages (XIXe-XXIe siècle) : ruptures métaboliques, conflictualités sociales et transitions environnementales
No full textCe dossier pluridisciplinaire réunit des contributions qui mettent en perspective l’histoire et le présent des déchets dans nos sociétés contemporaines. En présentant leurs usages multiples et parfois controversés, il souligne que la gestion des déchets revêt une dimension éminemment politique