Portail HAL-PSL
Not a member yet
293219 research outputs found
Sort by
Breaking barriers: the impact of ATLAS Virtual Visits in science communication
No full textInternational audienceThe ATLAS Collaboration at CERN's Large Hadron Collider is at the forefront of particle physics research and is equally committed to bridging the gap between cutting-edge science and the wider public. Since 2010, the ATLAS Virtual Visits programme has provided live, interactive tours of the ATLAS detector and control room to global audiences in their language, without the need to travel. The programme has grown significantly since its inception, as demonstrated by quantitative data collected since January 2019 and case studies of large-scale implementations in Brazil and Greece. The impact on individual participants is also discussed
Technological innovations and regional diversity in Western Europe at ca. the MIS 11 threshold: a cladistic approach
No full textInternational audienceThe ca: Marine Isotope Stage (MIS) 11 interglacial is considered to be a threshold for behavioural innovations in Western Europe. Innovations both in technology and subsistence are observed, as well as the appearance of Neanderthal anatomical features. Core technologies and Large Cutting Tools reflect changes in behaviours and innovations, with for instance, the onset and diffusion of the iconic Levallois core technology associated with more complex and standardized debitage. Following the severe glacial event of MIS 12, the lithic assemblages yield evidence of both innovations, but the chronology of their appearance remains unclear. For tracking these innovations and generally characterizing the technological and typological features of this period of time, a large database of the available ca. MIS 11 assemblages (from MIS 12 to MIS 10) has been built including a revision of some of the assemblages. In order to unravel the relationship between sites of this period, we applied a cladistic approach using three-item analysis, considering the assemblages themselves as the object of analysis, with an emphasis on core technology. We show how three-item analysis is an efficient method capable of correctly analysing characters from lithic technologies that appear to be intrinsically hierarchical. Our results suggest that Levallois core technology survived during the glacial event of MIS 12 and diversified during the long interglacial of MIS 11. Our results also show the absence of cultural endemism, which may be linked to significant mingling between northern and southern Europe
Generalized Leverage Score for Scalable Assessment of Privacy Vulnerability
No full textCan the privacy vulnerability of individual data points be assessed without retraining models or explicitly simulating attacks? We answer affirmatively by showing that exposure to membership inference attack (MIA) is fundamentally governed by a data point’s influence on the learned model. We formalize this in the linear setting by establishing a theoretical correspondence between individual MIA risk and the leverage score, identifying it as a principled metric for vulnerability. This characterization explains how data-dependent sensitivity translates into exposure, without the computational burden of training shadow models. Building on this, we propose a computationally efficient generalization of the leverage score for deep learning. Empirical evaluations confirm a strong correlation between the proposed score and MIA success, validating this metric as a practical surrogate for individual privacy risk assessment
Evaluating migration hazard for recently remobilized managed coastal dunes
No full textInternational audienceSparsely vegetated or unvegetated coastal dunes are inherently dynamic, regardless of their size (Hesp et al., 2022). A salient characteristic of these dunes is their landward migration, driven by prevailing onshore winds, at rates that can exceed several meters per year. The rapid evolution of freely evolving coastal dunes inevitably raises concerns about the burial of infrastructure and more generally, the back dune areas. In a context where dune system remobilization is emerging as a nature-based management solution with multiple benefits (ecological reconnection, chronic marine erosion and sea-level rise effects mitigation), precise, spatially explicit quantitative assessments of dune migration hazards are essential. This is more critical given the trends of increasing urbanization and the concentration of socio-economic interests in coastal zones.Along the 230 km of the Aquitaine coast (southwest France), coastal dunes, which landscape is largely inherited from nearly two centuries of management, stabilization, and episodic mechanical re-profiling, have undergone spontaneous remobilization over the past decade (Nicolae Lerma et al., accepted). Across extensive sectors, dunes have transitioned from geometrically fixed, vegetated forms to aerodynamic, transgressive dunes (Figure 1a). This shift presents both opportunities and challenges for short- and long-term management strategies but also raises critical questions about accommodating rapid migration rates and evolving dune morphology. Current approaches to assessing burial hazards often overlook key parameters, such as interannual wind variability, climate change-induced trends in forcing, dune and back-dune morphology, and sediment budgets. Furthermore, methods relying on historical migration rates are inapplicable in regions where dunes were artificially stabilized during the 20th century through management interventions.Using annual airborne LiDAR data (Figure 1b.) and simulations with the morphodynamic model DUNA (Kombiadou et al., 2023, Figure 1c.), we analyze the factors influencing the migration speed of recently unvegetated dunes. We also investigate the impact of hybrid management strategies (designed to either accelerate or mitigate dune remobilization) at large spatial scales (hundreds of meters to tens of kilometers)
Soil carbon literature review in the humanities and the social sciences
No full textInternational audienceDespite rising interest in the humanities and social sciences, as attested in this book, soil carbon remains scarcely addressed in these fields. This literature review introduces three emerging sets of literature in social and human sciences that started addressing the knowledge, governance and practices related to soil carbon. We do not aim for comprehensiveness: instead, we would like to outline some major inspirations and orientations of recent research into soil carbon. We shall distinguish between: -Social studies of soil carbon sciences – i.e. a strand of research in history and sociology that focuses on the social practices of knowledge production on soil carbon within the scientific communities, and their reconfigurations in the context of the fight against climate change. -Social studies of soil carbon economy – i.e. a strand of research in political ecology and economic sociology that analyses the rising focus on soils as carbon sinks in climate governance and the associated development of soil carbon accounting schemes and metrics. -Social studies of soil regeneration – i.e. a set of writings in environmental humanities that addresses soil organic matter regeneration understandings and practices, such as composting, in a range of rural and urban contexts
“La fronterización de los espacios: análisis crítico de las políticas de migración y asilo”, conférence à l'Université Pompeu Fabra, Barcelone, 24 mars 2026.
No full textInternational audienc
“La dimension externe de la politique européenne de migration et d'asile. Aspects juridiques”, communication durant le colloque Migration et diplomatie, Assemblée nationale, 5 février 2026.
No full textInternational audienc
Identifying phase transitions in zeolitic imidazolate frameworks: microscopic insight from molecular simulations
No full textInternational audienceMetal–organic frameworks (MOFs) feature a rich structural diversity, including crystalline, amorphous, and liquid phases of varying topologies. Their structural characterization is often performed either at the local scale (through pair distribution functions, bond angle distributions, etc.) or, for crystalline phases, through topology analysis of the periodic framework—leaving out disordered and amorphous phases. In this work, we develop a computational methodology for the structural characterization of middle-range order in MOFs that is applicable to both crystalline and amorphous phases. We base our method on the statistical analysis of the geometry of the supramolecular framework at the microscopic level, and its evolution during molecular simulation. We analyze the statistics of metal–organic rings, their distribution in size, as well as their geometrical characteristics through mathematical tools derived from polymer physics: radius of gyration, asphericity, and writhe. We show that this advanced characterization can be leveraged for the identification of phases and the detection and analysis of phase transitions
The odyssey of the black hole low mass X-ray binary GX339-4: Five years of dense multi-wavelength monitoring
No full textInternational audienceWe present the longest and the densest quasi-simultaneous radio, X-ray and optical campaign of the black hole low mass X-ray binary GX339-4, covering five years of weekly GX339-4 monitoring with MeerKAT, Swift-XRT and MeerLICHT, respectively. Complementary high frequency radio data with the Australia Telescope Compact Array are presented to track in more detail the evolution of GX339-4 and its transient ejecta. During the five years, GX339-4 has been through two "hard-only" outbursts and two "full" outbursts, allowing us to densely sample the rise, quenching and re-activation of the compact jets. Strong radio flares were also observed close to the transition between the hard and the soft states. Following the radio flare, a transient optically thin ejection was spatially resolved during the 2020 outburst, and was observed for a month. We also discuss the radio/X-ray correlation of GX339-4 during this five year period, which covers several states in detail from the rising phase to the quiescent state. This campaign allowed us to follow ejection events and provide information on the jet proper motion and its intrinsic velocity. With this work we publicly release the weekly MeerKAT L-band radio maps from data taken between September 2018 and October 2023
Demonstrating Ornament: Teaching through Drawing
No full textInternational audienceFrom 1834 to 1850, Eugène Viollet-le-Duc taught a course in the history and composition of ornament at the École royale gratuite de dessin, Paris. He used a teaching system involving drawing demonstrations in which he analyzed the origins of motifs from the past, then invited his students to compose for themselves. The concept of training the intellect before the hand had its start in the revision undertaken by Jean-Hilaire Belloc, the school’s director beginning in 1831. Viollet-le-Duc's demonstrations were spectacular performances during which he executed large motifs with a brush; few traces of these courses remain in the archives, unfortunately, but the approach resonates in his later thinking about the teaching of drawing as the language useful in every profession. Long before he published his Histoire d’un dessinateur (History of a designer: how one learns to draw, 1879), this early experience enabled him to think through the role he assigned to drawing in the training of children to become craftspeople or industrial designers