Asymptotically unbiased approximation of the QSD of diffusion processes with a decreasing time step Euler scheme

International audienceWe build and study a recursive algorithm based on the occupation measure of an Euler scheme with decreasing step for the numerical approximation of the quasistationary distribution (QSD) of an elliptic diffusion in a bounded domain. We prove the almost sure convergence of the procedure for a family of redistributions and show that we can also recover the approximation of the rate of survival and the convergence in distribution of the algorithm. This last point follows from some new bounds on the weak error related to diffusion dynamics with renewal

Strong Variability of the Modeled Venus NO Nightglow

International audienceThe ultraviolet nightglow of nitric oxide (NO) on Venus offers a unique window into the dynamics and chemistry of its upper atmosphere. We present three‐dimensional simulations of Venus' NO nightglow using a ground‐to‐thermosphere model, revealing a strong, short‐timescale variability consistent with observations. The Venus Planetary Climate Model accurately reproduces the altitude of peak emission at 115 km, matching SPICAV data, and shows an average peak brightness of 53 ± 33 kR, only 5% below the observed values. Crucially, the observed variability and morphology of the NO emission are tightly linked to atmospheric dynamics; its maxima strongly correlate with horizontal wind convergence, leading to localized subsidence. This downward transport is essential for delivering nitrogen atoms to fuel the nightglow, making it a critical tracer for understanding Venus's complex atmospheric circulation. Our findings underscore the importance of the NO nightglow as a powerful diagnostic for the solar‐to‐antisolar circulation on Venus

Maires, à quoi bon ?: Enquête au cœur des engagements municipaux

International audienceL"ouvrage explore les coulisses de l’engagement local à travers une enquête sociologique au long cours, centrée sur les petites communes, et fondée sur des entretiens approfondis avec des édiles. Loin d’envisager les départs de maires comme un phénomène d’épuisement ou de protestation, l’auteur révèle les dilemmes moraux, les tensions quotidiennes et les compromis silencieux qui structurent l’expérience ordinaire du pouvoir local. Il montre que l’engagement ne relève pas tant d’un élan héroïque que d’un apprentissage de la résignation, fait de renoncements, d’arrangements, mais aussi d’une fidélité à l’institution municipale.En retraçant avec minutie les parcours de vie et les trajectoires politiques de ces élus aux prises avec la charge mentale, la solitude décisionnelle et les injonctions contradictoires de l’État, l’auteur offre une plongée dans l’intimité du pouvoir local, dans les ressorts invisibles de sa reproduction, et propose une lecture incarnée de l’usure démocratique contemporaine

Cohabiter autrement une Terre urbaine vulnérable

National audienc

Accounting for exposure in 3D spatiotemporally contiguous heatwaves in Europe 1975-2024

Heatwaves are becoming more common, intense, and widespread as climate change strengthens, increasing their effects on infrastructure, economies, and health. However, heatwaves’ material and human effects cannot be adequately captured by their meteorological characteristics alone. In order to address this challenge, we propose a new heatwave index (HWMId_pop), which combines population exposure and meteorological data to provide a more exposure-informed characterization of heatwaves. Heatwaves are detected using a 3D-event framework, which considers heatwaves as spatiotemporal events that transcend conventional, spatially limited definitions. We evaluate this new index by comparing it to the heatwaves mortality recorded in the EM-DAT disaster database for Europe from 1975 to 2021. Our results show that HWMId_pop correlates more closely than traditional heatwave indices with mortality data. We also examine trends in several commonly used heatwave indices between 1975 and 2024, finding that our proposed index shows a significant increasing trend. We highlight that the increasing exposed population, driven by the expanding spatial extent of heatwaves and the rising European population, poses growing health risks. Additionally, we argue that this index can be used as a guide to carry out gap-filling in heatwaves impacts databases such as EM-DAT

Does Feasibility Explain the Unequal Development of Working From Home?

International audienc

Recourir à la justice pénale pour se sauver du régulateur ? Un dilemme pour les avocats d’affaires

International audienceThis paper highlights the fundamental role of business lawyers in the redefinition process of the traditional divide between administrative authorities and the criminal justice system. In contrast to the usual interpretation of Foucault’s thesis of differentiated management of illegalisms, this study reveals that the justice administered by regulatory agencies is not invariably favorable to defendants in cases of stock market violations. For their lawyers, turning to criminal justice can serve as a strategy to resist the dominance of the French stock market regulator in its authority to qualify such violations legally. This paper is based on the analysis of twenty-one semi-directive sociological interviews.Cette recherche met en évidence le rôle central des avocats d’affaires dans le processus de redéfinition de l’opposition traditionnelle entre les autorités administratives et la justice pénale. En décalage avec la lecture suggérée par la gestion différentielle des illégalismes, cette étude dévoile que la justice rendue par les autorités administratives n’est pas invariablement avantageuse pour les mis en cause du milieu financier. En effet, pour leurs avocats d’affaires, la justice pénale peut devenir un moyen d’échapper à la domination de l’Autorité des marchés financiers sur les opérations de qualification des illégalismes boursiers. Ce travail de recherche se fonde sur l’analyse de vingt-et-un entretiens semi-directifs

Designing and Producing a Library's Catalogue for an Engineering School in 19th Century France: The Ecole des Ponts et Chaussées' First General Printed Catalogue (1872)

International audienceThis article is devoted to the first general printed catalogue of the École des Ponts et Chaussées (EPC) library, which was published in 1872 and whose production spanned several decades. The article opens with a historical account of the EPC library, and proceeds to examine the principal episodes that shaped the conception, maturation, and implementation of the 1872 catalogue, while its last part is concerned with the place of mathematical sciences—rational and applied mechanics included—within that document. Finally, the article’s conclusion offers some general reflections on the process of designing and crafting library catalogues for engineering schools dedicated to the production of State engineers in 19th century France, while a special attention is given to the “patrimonialization” work carried out by those involved in the devising of the 1872 catalogue

Jean-Philippe Tonneau & Laurent Willemez (dir.), Pour une sociologie historique de la profession d’avocat. Bilan et nouvelles perspectives, Rennes, Presses universitaires de Rennes, 2025, 284 pages.

International audienc