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How much do we learn? Measuring symmetric and asymmetric deviations from Bayesian updating through choices
No full textInternational audienceBelief‐updating biases hinder the correction of inaccurate beliefs and lead to suboptimal decisions. We complement Rabin and Schrag's (1999) portable extension of the Bayesian model by including conservatism in addition to confirmatory bias. Additionally, we show how to identify these two forms of biases from choices. In an experiment, we found that the subjects exhibited confirmatory bias by misreading 19% of the signals that contradicted their priors. They were also conservative and acted as if they missed 28% of the signals.<br/
Changer pour apprendre : l’état d’esprit de développement comme levier de transformation éducative
No full textInternational audienceThis theoretical summation is dedicated to a thorough examination of the growth mindset and its transformative influence in the educational field, particularly through wise interventions, with a special focus on the contribution of Anglophone literature analyzed in French. Relying on existing works, we explore how the conceptualization of intelligence as a malleable trait can reshape pedagogical practices and promote academic resilience. However, the growth mindset theory has been the subject of debate, with some researchers highlighting the heterogeneity of effects depending on context and populations. Our analysis explores these controversies while suggesting ways to adapt and refine interventions based on specific needs. A practical guide is also included to support educators in implementing programs that foster a growth mindset. In conclusion, this note emphasizes the importance of integrating these principles into the French educational system to maximize students’ learning potential.Cette synthèse théorique se consacre à l’examen approfondi de l’état d’esprit de développement et de son influence transformatrice dans le domaine éducatif, notamment via les interventions psychosociales, avec un accent particulier sur l’apport de la littérature anglophone analysée en français. En s’appuyant sur des travaux existants, nous explorons comment la conceptualisation de l’intelligence comme une capacité évolutive peut remodeler les pratiques pédagogiques et promouvoir la résilience académique. Toutefois, la théorie de l’état d’esprit de développement fait l’objet de débats, certains chercheurs soulignant l’hétérogénéité des effets selon les contextes et les populations. Notre analyse examine ces controverses tout en proposant des pistes pour adapter et affiner les interventions en fonction des besoins spécifiques. Un guide pratique est également inclus pour soutenir les enseignant·es dans la mise en place de programmes favorisant un état d’esprit de développement. En conclusion, cette note souligne la pertinence d’intégrer ces principes au sein du système éducatif français pour optimiser le potentiel d’apprentissage des élèves
Conflits politiques en milieu rural
No full textInternational audienceSi l'intégration politique des mondes ruraux a retenu l'attention des chercheurs dès la fin du XIXe siècle, les luttes politiques en milieu rural n'ont quant à elles fait l'objet que d'une attention ponctuelle de la part de la science politique. Cet ouvrage entend montrer combien les dynamiques sociales nourrissant les engagements politiques y sont loin d'être uniformes. Il met l'accent sur la grande diversité d'acteurs (néoruraux, urbains "d'occasion", ruraux "autochtones", etc.) mais aussi de thématiques qui alimentent la vie politique rurale, depuis des questions d'apparence anodine (mais qui charrient de lourds enjeux de définition des normes de vivre ensemble) jusqu'à des questions de politique nationale qui trouvent localement un lieu d'expression et d'appropriation.L'objectif de cet ouvrage est de contribuer à comprendre, à travers des études de cas localisés, les multiples clivages et controverses qui traversent les mondes ruraux, en analysant les conflits de valeurs et d'intérêts qu'ils manifestent pour en faire ressortir les fondements politiques. Il réunit des chercheurs issus de plusieurs disciplines : science politique, mais aussi histoire du droit, sociologie, histoire, droit public
Synthesis of Knowledge on Infant Fortification Plants and the Most Commonly Used Galactogenic Plants in Niger and Their Uses in the Republic of Niger
No full textInternational audienceThe use of plants for therapeutic purposes is an ancestral practice that dates back to the earliest times in the history of mankind. Even today the exploitation of plants for medicinal purposes plays a big role for the communities, especially in Africa, despite advances in modern medicine. According to the World Health Organization, about 80% of the population in developing countries use plants for their primary health care. In Niger, the use of medicinal plants is a foundation of traditional medicine across all ages. It remains a very common practice, especially in rural areas. This practice concerns all ages of life, including mother–child care. In infants and young children, mothers use plants as fortifiers for their prophylactic or curative powers, or to facilitate growth and weight gain, and also to fight major causes of infant morbidity and mortality. Mothers also use medicinal plants for their galactogenic power to stimulate lactation. This is even more important in rural areas where breastfeeding is the main source of infant nutrition. Over the years, these medicinal plants have been the subject of chemical and biological investigations to back up their therapeutic potential and virtues. This study aims to summarize current knowledge on the most commonly used medicinal plants in Niger in mother–child care. This helps emphasize the validation of ancestral medicinal plants through the scientific evaluation of the bioactive components and mechanisms. Elements of sustainability are discussed in future developments
The electrochemical performance of Ta2O5 thin films in ionic liquid and ionogel electrolytes
No full textInternational audienceIn this work, we present a new cell design for miniaturized energy storage devices by realizing a hybrid microcapacitor, which uses for the first time a TaN/ Ta 2 O 5 thin film electrode in combination with a MnO 2 composite electrode. In this proof of concept study, the electrochemical performance of the dielectric material Ta 2 O 5 was of main interest. Therefore, various tantalum oxide films with different thicknesses from 23 to 80 nm have been tested in combination with a pseudocapacitive oversized MnO 2 composite electrode. This was done with two model electrolytes, namely the ionic liquid Emim FSI and the solid-state ionogel Emim FSI: PVdF 80:20. Surface capacitance values up to 1.94 µF cm -2 in Emim FSI and 2.84 µF cm -2 in IG Emim TFSI: PVdF 80:20 have been reached at high scan rates (100 mV s -1 ) with no significant distortion of the voltammograms. When films of 47 and 80 nm thickness of Ta 2 O 5 are used, stable cycling with scan rates of up to 5000 mV s -1 at a cell voltage of 20 V can be achieved even in solid-state ionogel electrolyte. This performance highlights the promising characteristics of these materials and cell concept for miniaturized high power energy storage application and opens the way for further investigations to improve this needed technology
Enhancing the prediction of arsenic bioavailability in soils with the diffusive gradient in thin film technique
No full textInternational audienc
Reliability and Accuracy of the Fitbit Charge 4 Photoplethysmography Heart Rate Sensor in Ecological Conditions : Validation Study
No full textInternational audienceBackground :Wrist-worn photoplethysmography (PPG) sensors allow for continuous heart rate (HR) measurement without the inconveniences of wearing a chest belt. Although green light PPG technology reduces HR measurement motion artifacts, only a limited number of studies have investigated the reliability and accuracy of wearables in non–laboratory-controlled conditions with actual specific and various physical activity movements. Objective : The purpose of this study was to (1) assess the reliability and accuracy of the PPG-based HR sensor of the Fitbit Charge 4 (FC4) in ecological conditions and (2) quantify the potential variability caused by the nature of activities. Methods :We collected HR data from participants who performed badminton, tennis, orienteering running, running, cycling, and soccer while simultaneously wearing the FC4 and the Polar H10 chest belt (criterion sensor). Skin tone was assessed with the Fitzpatrick Skin Scale. Once data from the FC4 and criterion data were synchronized, accuracy and reliability analyses were performed, using intraclass correlation coefficients (ICCs), Lin concordance correlation coefficients (CCCs), mean absolute percentage errors (MAPEs), and Bland-Altman tests. A linear univariate model was also used to evaluate the effect of skin tone on bias. All analyses were stratified by activity and pooled activity types (racket sports and running sports). Results :A total of 77.5 hours of HR recordings from 26 participants (age: mean 21.1, SD 5.8 years) were analyzed. The highest reliability was found for running sports, with ICCs and CCCs of 0.90 and 0.99 for running and 0.80 and 0.93 for orienteering running, respectively, whereas the ICCs and CCCs were 0.37 and 0.78, 0.42 and 0.88, 0.65 and 0.97, and 0.49 and 0.81 for badminton, tennis, cycling, and soccer, respectively. We found the highest accuracy for running (bias: 0.1 beats per minute [bpm]; MAPE 1.2%, SD 4.6%) and the lowest for badminton (bias: −16.5 bpm; MAPE 16.2%, SD 14.4%) and soccer (bias: −16.5 bpm; MAPE 17.5%, SD 20.8%). Limit of agreement (LOA) width and artifact rate followed the same trend. No effect of skin tone was observed on bias.Conclusions :LOA width, bias, and MAPE results found for racket sports and soccer suggest a high sensitivity to motion artifacts for activities that involve “sharp” and random arm movements. In this study, we did not measure arm motion, which limits our results. However, whereas individuals might benefit from using the FC4 for casual training in aerobic sports, we cannot recommend the use of the FC4 for specific purposes requiring high reliability and accuracy, such as research purposes
Molecular modeling of clay minerals: A thirty-year journey and future perspectives
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Rigidity-Driven Structural Isomers in the NaCl–Ga2S3 System: Implications for Energy Storage
No full textInternational audienceAlternative energy sources require the search for innovative materials with promising functionalities. Systems with unusual chemical properties represent an insufficiently explored domain, concealing unexpected features. Using diffraction and Raman spectroscopy over a wide temperature range, supported by first-principles simulations, a rare phenomenon is unveiled: phase-dependent chemical interactions between binary components in the NaCl–Ga2S3 system. In this unique occurrence, previously intact binary crystalline species transform upon melting into mixed liquid structural isomers, forming bonds with new partners. The chemical combinatorics appears to be fully reversible for stable crystals and liquids. Despite this, rapidly frozen glasses out of thermodynamic equilibrium remain in a metastable isomeric state, offering remarkable properties, particularly a high room-temperature Na+ conductivity, comparable to the best sodium halide superionic conductors and therefore encouraging for sodium solid-state batteries and energy applications. A rigidity paradigm is responsible for the observed phenomenon, as the extremely constrained Ga2S3 crystal lattice does not survive viscous flow, breaking up at a short-range level. The removal of rigidity constraints and dense packing leads to a significant increase in empty space, which is the origin of high sodium diffusivity. Broadly, the rigidity-driven structural isomerism opens up an inspiring path to the discovery of atypical materials
