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Neutralité et maintien de la paix : réflexions sur les fondements d'une idée reçue
No full textDossier thématique : Neutralité(s) ?International audienc
Dynamiques spatio-temporelles des formes d'occupation du sol dans le bassin de la Moyenne Casamance au prisme des changements climatiques
No full textInternational audienceLand use dynamics analysis is critical for understanding territorial transformations in West Africa, especially in regions under significant environmental and human pressure. This study investigates spatio-temporal changes in landscape units in the Middle Casamance basin (Senegal) from 1972 to 2020, a period marked by major socio-economic, political, and climatic changes. Using Landsat satellite data from the USGS and processed with ArcGIS and ENVI software, we produced diachronic land use and change maps through supervised classification. The results highlight a significant decline in vegetated areas and bare soils, in favor of the expansion of built-up areas and water bodies. This trend is driven by multi-scalar factors, including climatic variability, erosion, salinization of lowlands, regional armed conflicts, and demographic pressure. The gradual abandonment of traditional rice farming in some areas contrasts with revitalization efforts observed elsewhere. These findings reveal the scale of ongoing territorial recompositions and underscore the need for sustainable land use planning that addresses food security and climate change adaptation challenges.L’analyse des dynamiques d’occupation du sol constitue un enjeu majeur pour la compréhension des transformations territoriales en Afrique de l’Ouest, particulièrement dans les régions soumises à de fortes pressions environnementales et humaines. Cette étude s’intéresse à l’évolution spatio-temporelle des unités paysagères dans le bassin de la Moyenne Casamance (Sénégal) entre 1972 et 2020, une période marquée par de profondes mutations socio-économiques, politiques et climatiques. En mobilisant des données satellitaires Landsat issues de l’USGS et traitées à l’aide des logiciels ArcGIS et ENVI, nous avons élaboré des cartes d’occupation des sols et de changement diachronique, à travers une classification supervisée. Les résultats mettent en évidence une régression significative des surfaces végétalisées et des terres nues, au profit de l’expansion des zones bâties et des surfaces en eau. Cette dynamique est alimentée par des facteurs multiscalaires, tels que la variabilité climatique, l’érosion, la salinisation des bas-fonds, les conflits armés régionaux et la pression démographique. L’abandon progressif de la riziculture dans certaines zones contraste avec les efforts de revitalisation observés ailleurs. Ces résultats révèlent l’ampleur des recompositions territoriales à l’œuvre et soulignent la nécessité d’une planification durable de l’usage des sols, en intégrant les enjeux de sécurité alimentaire et d’adaptation au changement climatique. Abstract Land use dynamics analysis is critical for understanding territorial transformations in West Africa, especially in regions under significant environmental and human pressure. This study investigates spatio-temporal changes in landscape units in the Middle Casamance basin (Senegal) from 1972 to 2020, a period marked by major socio-economic, political, and climatic changes. Using Landsat satellite data from the USGS and processed with ArcGIS and ENVI software, we produced diachronic land use and change maps through supervised classification. The results highlight a significant decline in vegetated areas and bare soils, in favor of the expansion of built-up areas and water bodies. This trend is driven by multi-scalar factors, including climatic variability, erosion, salinization of lowlands, regional armed conflicts, and demographic pressure. The gradual abandonment of traditional rice farming in some areas contrasts with revitalization efforts observed elsewhere. These findings reveal the scale of ongoing territorial recompositions and underscore the need for sustainable land use planning that addresses food security and climate change adaptation challenges
High-entropy Tungsten-Based Oxide as Electrocatalyst and Potential Photo-electro-catalyst for H 2 Evolution
No full textInternational audienceHigh-entropy oxides (HEOx) have emerged as a promising class of materials for photocatalysis due to their unique properties and exceptional stability. This study investigates ( Co 0.2 Ni 0.2 Fe 0.2 Cu 0.2 Zn 0.2 )WO 4 HEOx material synthesized using a top-down approach. The material exhibits a single phase, a suitable band gap for visible light absorption, and a promising electrocatalyst for oxygen evolution reaction (OER) compared to their corresponding individual tungstates. Additionally, the initial tests for Photo-current and MB degradation show the potential for hydrogen (H 2 ) production, making HEOx potential catalysts for solar-driven H 2 generation. ΔS mix = RΣ x n lnx n</div
[Interview par Hélène Bannier de Vivant le Média] Pour réduire les risques d’inondation, le Clain a son jumeau numérique
No full textPodcast - https://soundcloud.com/vivant-la-radio/pour-reduire-le-risque-dinondation-le-clain-a-son-jumeau-numeriqueAfin d’améliorer les connaissances locales sur le Clain et réduire les risques d’inondation pour la population, Grand Poitiers et l’institut Pprime de l’université de Poitiers ont créé un jumeau numérique de la rivière. Ce sont près de 5 kilomètres qui ont été modélisés entre l’îlot Tison et la base kayak de Saint-Benoît.Cette reproduction numérique permet d’analyser, à partir d’un ordinateur, le bon état écologique du cours d’eau, mais aussi de projeter des scénarios d’aménagement qui favorisent la biodiversité tout en limitant l’impact des crues potentielles. Un outil essentiel pour la communauté urbaine de Grand Poitiers qui a, depuis 2018, la compétence GEMAPI (gestion des milieux aquatiques et prévention des inondations)
Cours d'Introduction historique au droit et d'histoire des institutions
No full textInternational audienc
une explication approfondie du rôle des polymères dans la synthèse en vrac du fluorure de magnésium (MgF₂) pour la fluoration du 2-chloropyridine
No full textInternational audienceMgF 2 is one of the most active catalysts for the Cl/F exchange in the transformation of 2‐chloropyridine. This study presents a more environmentally friendly and straightforward method for preparing bulk MgF 2 nanoparticles (NP) in aqueous solution. The presence of a structuring agent such as PMMA or Pluronic F68 as polymers, leads to a higher specific surface area after HF treatment (around 30%). It contributed to its preservation under hydrogen fluoride, reflecting the operating conditions for the fluorination of 2‐chloropyridine. Regarding the catalytic activity, no change was observed for NP MgF 2 synthesized in water with or without microwave heating. In contrast, an increase (around 20%) in activity for the transformation of 2‐chloropyridine was noted when a polymer was used during the preparation correlating with an increase of the specific surface area
Chemical reactivity from linear response eigenfunctions and eigenvalues
No full textInternational audienceThe atom-condensed linear response function matrix can be diagonalized, and the associated eigenvectors thus obtained form a complete basis set on which any density deformation can be projected. In this paper, one proposes to interpret these vectors as atom condensed Electron Density Deformation Modes. Each eigenvector represents a mode describing how electron density can deformed in response to an external potential perturbation. It is hypothesized that these modes can reveal the preferred direction or pattern of electron flow, helping identifying the reactive region of a molecule. A relationship between electron density polarization energy and hardness variation is also derived. Practical applications on organic reactions are provided
Electrocardiogram vs Electrophysiological Study and Major Conduction Delays in Myotonic Dystrophy Type 1
No full textInternational audienceImportance: For the prevention of sudden cardiac death in myotonic dystrophy type 1 (dystrophia myotonica; DM1), professional practice guidelines recommend pacemaker implantation in asymptomatic patients with a PR interval greater than or equal to 240 milliseconds and/or QRS duration greater than or equal to 120 milliseconds on electrocardiogram (ECG), or a His-ventricular (HV) interval greater than or equal to 70 milliseconds during electrophysiological study (EPS), as class IIa indications.Objective: To determine which of these strategies—ECG or EPS based—is more effective in predicting major bradyarrhythmic events (MBAEs).Design, Setting, and Participants: This was a cohort analysis of retrospectively collected longitudinal data from the DM1 Heart Registry. The setting included cardiology and neurology departments of 6 French university hospitals. Study participants were selected from individuals enrolled in the DM1 Heart Registry between 2000 and 2020. The DM1 Heart Registry includes adults with genetically confirmed DM1. Included patients had a history of first EPS after 1999 and no personal history of advanced atrioventricular block or sustained ventricular tachycardia. Study data were analyzed from January to July 2025.Exposures: ECG- and EPS-based strategies.Main Outcomes and Measures: The primary outcome was MBAEs, defined as sudden cardiac death, resuscitated cardiac arrest, or second-degree II or complete atrioventricular block.Results: Of 1778 adults with genetically confirmed DM1 enrolled in the DM1 Heart Registry, a total of 706 patients (mean [SD] age, 42 [13] years; 359 male [51%]) were included in this study. At baseline, 273 patients (38%) had an HV interval greater than or equal to 70 milliseconds, and 232 (32%) met ECG criteria. Over a median (IQR) follow-up of 5.9 (2.3-9.7 years, 99 patients (14%) experienced an MBAE. In multivariable Cox and joint models incorporating baseline and time-varying values of PR and QRS durations, the HV interval was the only variable significantly associated with the incidence of MBAEs (hazard ratio [HR], 1.77; 95% CI, 1.46-2.16; P P = .001, respectively). Compared with ECG-based criteria, the EPS criterion proved to be a more reliable (HR, 2.89; 95% CI, 1.92-4.34 vs HR, 1.95; 95% CI, 1.31-2.89) and more sensitive (performance index [SE], 68.35% [6.24%] vs 34.76% [6.47%]) predictor of MBAE and accurately reclassified 28.8% of patients with an MBAE. Lowering the threshold to HV greater than or equal to 65 milliseconds further improved sensitivity (performance index [SE], 90.18% [3.85%]) and net reclassification improvement (33.7%; 95% CI, 19.6%-48.2%) for MBAE prediction.Conclusions and Relevance: In this cohort of patients with DM1, the HV interval outperformed ECG criteria in predicting MBAEs. An HV threshold greater than or equal to 65 milliseconds may enhance risk stratification for prophylactic pacing
Le café du capitaine Georgeon: horizon, liaison, héritage (1771-1832)
No full textInternational audienc