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Fine-scale fishery patterns reveal challenges and opportunities for coastal management and conservation in Madagascar
No full textInternational audienceThe blue economy agenda has generated tensions over marine space use, often marginalising small-scale fisheries in development policies. Boat tracking technology has only recently begun to be applied in these fisheries, but it offers a promising approach to accurately map fishing distribution. In this study, we explored how environmental, technological, and social factors influenced fishers’ spatial behaviour and catches at sea in one of the Madagascar's most heavily exploited coral reef fisheries. We recorded boat movements at 30 s intervals and reef fish catches simultaneously during a 12-month participatory survey. The spatial distribution of annual fishing effort (h·ha −1 ) and fish catch rates (kg·ha −1 ) was characterised by fishing community and gear type (beach seine, mosquito net trawl, gillnet, handline, and speargun) at 250−m resolution. A total of 75 reef fish families were recorded in catches (1,466 t·yr −1 ) across approximately 218 km 2 . Annual catch rates of the seven dominant families (comprising 62% of total catches) were highly variable and heterogeneous (mostly 1–391 kg·ha −1 ) across marine habitats. A total of 7,359 tracks by 521 boats were recorded. Fishing pressure was highly variable spatially (mostly 1−150 h·ha −1 ) among communities and gear types. The results revealed preferential target areas, informal marine tenure, limited travel distance to fishing grounds, and overexploitation patterns within the fishery, offering critical insights for fishery management and inclusive marine spatial planning. This study showed the usefulness and opportunities of deploying combined boat tracking and catch surveys in small-scale fisheries through participatory research
Intermediate-complexity parameterisation of blowing snow in the ICOLMDZ AGCM: development and first applications in Antarctica
No full textInternational audienceRecent regional model findings suggest that the aeolian erosion of surface snow is a significant contribution to the overall Antarctic surface mass balance (SMB) through ice crystals sublimation and export outside of the ice sheet. Such findings raise the question of the relevance of accounting for such a process also in global climate models. This study presents the development of an intermediate-complexity parameterisation of blowing snow for the ICOLMDZ atmospheric general circulation model, the atmospheric component of the IPSL Coupled Model. The parameterisation is designed to be a trade-off between physical complexity and applicability in a general circulation model, with constraints on numerical cost and stability. The parameterisation is evaluated with in situ observations using limited-area simulations over Adélie Land. The model exhibits satisfactory results in terms of summer wind speed, temperature and intensity of blowing snow fluxes. In winter, blowing snow intensity and occurrences are overestimated close to the coast, concurring with a positive wind speed bias. In terms of blowing snow occurrences throughout the year, ICOLMDZ exhibits comparable performance with the regional atmospheric model MAR. Boundary-layer moistening and cooling as well as changes in surface radiative fluxes due to blowing snow crystals are also quantified in the simulations. Global simulations at standard global climate model resolution are carried out to investigate how the Antarctic SMB is modified with the activation of the blowing snow parameterisation. Results show an overall decrease of the net snow accumulation in the escarpment region due to surface snow erosion and an increase along the coast due to blowing snow deposition and increase in precipitation
Privacy Settings and Ad Perception: The Shift from Third-Party Cookies to the Privacy Sandbox
No full textInternational audienceOnline behavioral advertising, heavily reliant on privacy-invasive third-party cookie tracking, faces a significant shift as browsers like Safari, Brave, and Firefox have already deprecated them. Google Chrome announced its parallel move with the "Privacy Sandbox Initiative" in 2019, proposing privacy-preserving advertising mechanisms. The extent to which Privacy Sandbox can deliver comparable ad effectiveness to the established third-party cookies system will likely determine its adoption as a widespread alternative. This paper presents the first user study evaluating the impact of Privacy Sandbox APIs on ad perception. Our findings show that users perceive Privacy Sandbox ads as less relevant and exhibit lower purchase intent compared to third-party cookie-based ads, without a corresponding increase in perceived privacy protection. These results contribute to the ongoing assessment of Privacy Sandbox as an alternative to third-party cookies
Mesons, baryons and the confinement/deconfinement transition
No full textInternational audienceWe relate the Polyakov and anti-Polyakov loops, which determine how energetically costly it is to bring an external static quark or antiquark probe into a bath of quarks and gluons, to the ability of that same medium to provide the conditions for the formation of meson-like or baryon-like configurations that would screen the probes
Local characterization of block-decomposability for multiparameter persistence modules
No full textversion accepted in Homology, Homotopy and ApplicationsInternational audienceLocal conditions for the direct summands of a persistence module to belong to a certain class of indecomposables have been proposed in the 2-parameter setting, notably for the class of indecomposables called block modules, which plays a prominent role in levelset persistence. Here we generalize the local condition for decomposability into block modules to the n-parameter setting, and prove a corresponding structure theorem. Our result holds in the generality of pointwise finite-dimensional modules over finite products of arbitrary totally ordered sets. Our proof extends the one by Botnan and Crawley-Boevey from 2 to n parameters, which requires some crucial adaptations at places where their proof is fundamentally tied to the 2-parameter setting
Utiliser la microsimulation pour estimer les inégalités en temps réel ? Une illustration avec Taxipp
No full textL’objectif de ce projet est développer le modèle de microsimulation Taxipp pour mieux estimer la distribution à court terme du revenu des ménages. Deux améliorations majeures sont ainsi apportées au modèle : l’affinement du vieillissement et la mensualisation des revenus.Cela nous permet aussi d’examiner s’il est possible d’utiliser des données disponibles à court terme pour présenter de premières estimations de l’évolution de la pauvreté et des inégalités dans l’attente de la confirmation des tendances par les données précises d’enquête
Investigating the role of climate change in the 3 May 2025 Western Europe hailstorm using atmospheric analogues
No full textInternational audienceOn 3 May 2025, a severe hailstorm struck Paris and parts of western Europe, raising concerns about the influence of climate change. We analyze this event using ERA5 reanalysis and an analogue-based attribution framework. The synoptic setting involved a cut-off low and a surface cold front, occurring shortly after an early-season heatwave. We compare analogous patterns in past (1974–1999) and recent (1999–2024) climates to assess thermodynamic differences. Hail probability and size were estimated with two models: a logistic formulation based on convective available potential energy, wind shear, and convective precipitation, and a new model incorporating freezing-level height and 850 hPa temperature, designed for European hail environments. Both were calibrated with Ile-de-France observations and validated with independent data. Our findings show that present-day conditions favor higher hail probabilities and larger hailstones, suggesting anthropogenic warming has likely enhanced hailstorm intensity in the region
Fast, faithful and photorealistic diffusion-based image super-resolution with enhanced Flow Map models
No full textTechnical reportDiffusion-based image super-resolution (SR) has recently attracted significant attention by leveraging the expressive power of large pre-trained text-to-image diffusion models (DMs). A central practical challenge is resolving the trade-off between reconstruction faithfulness and photorealism. To address inference efficiency, many recent works have explored knowledge distillation strategies specifically tailored to SR, enabling one-step diffusion-based approaches. However, these teacher-student formulations are inherently constrained by information compression, which can degrade perceptual cues such as lifelike textures and depth of field, even with high overall perceptual quality. In parallel, self-distillation DMs, known as Flow Map models, have emerged as a promising alternative for image generation tasks, enabling fast inference while preserving the expressivity and training stability of standard DMs. Building on these developments, we propose FlowMapSR, a novel diffusion-based framework for image super-resolution explicitly designed for efficient inference. Beyond adapting Flow Map models to SR, we introduce two complementary enhancements: (i) positive-negative prompting guidance, based on a generalization of classifier free-guidance paradigm to Flow Map models, and (ii) adversarial fine-tuning using Low-Rank Adaptation (LoRA). Among the considered Flow Map formulations (Eulerian, Lagrangian, and Shortcut), we find that the Shortcut variant consistently achieves the best performance when combined with these enhancements. Extensive experiments show that FlowMapSR achieves a better balance between reconstruction faithfulness and photorealism than recent state-of-the-art methods for both x4 and x8 upscaling, while maintaining competitive inference time. Notably, a single model is used for both upscaling factors, without any scale-specific conditioning or degradation-guided mechanisms
Validation of EarthCARE CPR reflectivity using the ACTRIS cloud radar network
No full textInternational audienceThe Earth Cloud, Aerosol, and Radiation Explorer (EarthCARE) satellite carries a cloud profiling radar (CPR) designed to observe global cloud properties. In this study, we assess the calibration of CPR reflectivity profiles by comparing them with seven calibrated ground-based cloud radars from the European Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS).We compare the statistics of ice cloud reflectivities observed from space and from each ground site. The CPR dataset includes all observations within a 200 km radius of each site, while the ground-based dataset comprises vertical profiles collected during the same time period. By analysing the differences in reflectivity statistics, we estimate the calibration bias between CPR and each site. To ensure robustness, we implement a method to select height bins with comparable reflectivity statistics, excluding uncorrelated observations that could contaminate the results. The reliability of our bias estimates is validated through closure: each ground radar has been calibrated using the same reference, and the independently derived space-versus-ground biases obtained across sites are consistent. Our methodology also provides uncertainty estimates for the reflectivity biases and explores the time sampling required for reliable comparisons.Based on the comparisons from the seven ground-sites, we find that the bias in the EarthCARE L2a reflectivity product is of -0.2 ± 0.4 dB, confirming the high quality of the satellite's calibration. This robust statistical approach, validated with calibrated radars, establishes EarthCARE as a potential reference for calibrating ACTRIS and other ground-based sites in the future
Quantitative approximation of a Keller–Segel PDE by a branching moderately interacting particle system and suppression of blow-up
No full textThe Keller–Segel PDE is a model for chemotaxis known to exhibit possible finite-time blow-up. Following a seminal work by Tello and Winkler [43], a logistic damping term is added inthis PDE and local well-posedness of mild solutions is proven. When the space dimension is2 or when the damping is strong enough, the solution is global in time. In the second partof this work, a microscopic description of this model is introduced in terms of a system ofstochastic moderately interacting particles. This system features two main characteristics:the interaction between particles happens through a singular (Coulomb-type) kernel which isattractive; and the particles are subject to demographic events, birth and death due to localcompetition with other particles. The latter induces a branching structure of the particlesystem. Then the main result of this work is the convergence of the empirical measure ofthe particle system towards the Keller–Segel PDE with logistic damping, with a rate of orderN − 12(d+1)