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Drivers of alpine-treeline-ecotone dynamics in the Pyrenees
No full textInternational audienceAimWhile alpine-treeline ecotones are expected to shift upwards and densify under climate warming, observed dynamics vary across mountain ranges. Most studies focus solely on elevational shifts, yet different dimensions may respond to different drivers—limiting our ability to predict ecosystem responses. We examined multiple aspects of treeline ecotone changes (elevational shifts, spatial-pattern changes, and infilling) in the temperate mountain range of the Pyrenees, focusing on the eastern French sector, and uncovered interactions between climate, topography, land use, and lithology at different spatial scales.MethodsWe studied 626 treeline ecotones in the eastern French Pyrenees to examine elevational shifts, spatial-pattern changes, and infilling in relation to climate, land-use, and habitat drivers. Regression and factorial analyses identified key drivers and recurrent environmental combinations affecting treeline ecotone dynamics.ResultsThree environmental clusters revealed contrasting regional dynamics across the eastern French Pyrenees. Western treeline ecotones showed the strongest upward shift, central treeline ecotones exhibited the highest local infilling, and eastern high-elevation treeline ecotones displayed downward shift and diffuse patterns. Overall, local topography influenced fine-scale infilling, while regional land-use and biogeographic contexts controlled broader treeline ecotone elevational shift, highlighting how different drivers operate at multiple spatial scales.ConclusionUnderstanding the effects of climate change requires considering multiple dimensions beyond elevational shifts, as each aspect of treeline ecotone dynamics responds differently to drivers operating at different spatial scales. Management strategies should adapt to multi-scale contexts rather than uniform approaches, particularly where treeline ecotone structure indicates scale-dependent processes
Clearing the Air : A Longitudinal Study of Air Pollution in the French Media
No full textAir pollution is a major environmental and public health issue that has gradually attracted media attention over the past two decades. This longitudinal study examines how the French media represented pollution from 2004 to 2024, by analyzing a corpus of 1166 press articles from national and local media with various political orientations. Using a computer-assisted content analysis, we identified distinct phases of media coverage that describe an evolution from an initially scientific and health-focused discourse, to a more political, legislative, and territorialized discursive debate. Our results reveal that air pollution has evolved from a technical environmental problem to a controversial public object marked by legal action, local governance debates and citizen mobilization. This study contributes to understanding the social construction of environmental risks in media discourse, and highlights the role of the press in public perception and political debate
Oncogenic MAPK pathway activation induces a congenital and progressively lethal rare neuropathy in mice
No full textRASopathies, rare congenital syndromes affecting multiple organ systems, often include peripheral neuropathy of unknown origin. While RASopathy gene variants are protooncogenic, how timing of onset changes prenatal pathogenicity remains unclear. This study investigates the links between Braf, a mitogen-activated protein kinase (MAPK) effector, and peripheral neuropathy. Targeting Braf(V600E), an oncogenic variant in mosaic RASopathies, to embryonic Mpz-expressing cells in mice triggered a congenital Charcot-Marie-Tooth-like degenerative neuropathy, with hyperplastic nerves, hindlimb weakness, and unexpectedly reduced body size. Constitutively active Braf expanded a Jun+ Schwann cell repair state, impairing myelination. Patient-derived iPSCs with the cardio-facio-cutaneous syndromeassociated BRAF Q257R variant also failed to differentiate into mature Schwann cells compared to WT, instead exhibiting progenitor or repair-type transcriptional profiles. These findings implicate somatic mosaicism in the unresolved genetic heterogeneity of neuropathies and expand the candidate gene list. A MAPK-dependent mechanism ties neural crest-derived Schwann cell dysfunction to both body growth and nerve homeostasis.</div
Second-moment turbulent models for incompressible flows : some recent -and less recent- results
No full textInternational audienc
Sources
No full textNotice dédiée à Sources, revue d'études anglophones (1996-2008), dont la spécificité était la publication d'entretiens et interviews
First evidence of the decay
No full textInternational audienceThe first search for the decay in the range is performed using data from proton-proton collisions collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb. The photons are reconstructed through their conversion into an electron-positron pair, which significantly improves the mass resolution of the reconstructed decays with respect to decays with an unconverted photon. A signal excess with a significance of 3.5 standard deviations is measured, constituting the first experimental evidence for this decay. In the range , the ratio between the branching fractions of the signal decay and the favoured decay is measured to be where the first uncertainty is statistical and the second is systematic. This measurement is consistent with the value predicted in the Standard Model. In the range , the ratio is measured
Hacking the Apocalypse: How Cyberattacks Could Trigger Nuclear Escalation
No full textStrategic doctrines inherited from the Cold War continue to rest largely on the assumption that nuclear escalation can arise only from a conventional military attack. The rapid expansion of cyber operations, however, fundamentally challenges this paradigm. Sophisticated digital offensives are now capable of paralyzing critical infrastructure, disrupting entire economies, and degrading military command-and-control systems without formally crossing the traditional thresholds of armed conflict. This evolution has created a strategic gray zone in which adversaries can probe the resilience of democratic states at relatively low political and military cost. The growing vulnerability of civilian infrastructure, the increasing digitization of nuclear-related systems, and the rising assertiveness of both terrorist organizations and authoritarian regimes further amplify the risks of misperception and unintended escalation.Considering these developments, clearer doctrinal frameworks are required to reestablish credible deterrence while avoiding both a lowering of the nuclear threshold and the danger of disproportionate or destabilizing responses.</p
Contributions to the mathematical analysis of constrained flows
No full textThis habilitation thesis is dedicated to the mathematical study of congestion phenomena in fluids, that is, the study of flows subjected to a maximum density constraint. This thesis provides an overview of the results - and open questions - of theoretical and numerical analysis on these congested flow models.In the first part, we focus on the "standard" Navier-Stokes equations (with constant viscosities) and barotropic compressible Euler equations, including a maximum density constraint. In one spatial dimension, we present well-posedness and asymptotic stability results in the vicinity of particular (partially congested) solutions, such as traveling wave or self-similar solutions. We also address the case of multi-dimensional equations with a numerical approach.In the second part of this manuscript, we turn our attention to mathematical models that deviate from classical Navier-Stokes equations to account for more "complex" phenomena, such as the heterogeneity of fluids. Specifically, we deal with granular suspensions and porous media, focusing on issues related to transitions between different flow regimes near the congestion constraint and, once again, on stability analysis around traveling wave profiles.Ce mémoire d'habilitation à diriger des recherches est consacré à l'étude mathématique de phénomènes de congestion dans les fluides, c'est-à-dire à l'étude d'écoulements soumis à une contrainte de densité maximale. Ce mémoire dresse un état des lieux des résultats -et questions ouvertes d'analyse d'ordre théorique et numérique sur ces modèles de flots congestionnés. Dans une première partie, nous nous intéressons aux équations "standards" de Navier-Stokes (à viscosités constantes) et d'Euler compressible barotrope, incluant une contrainte de densité maximale. En dimension un d'espace, nous présentons des résultats de caractère bien-posé et de stabilité asymptotique au voisinage de solutions particulières (de type onde progressive ou solution auto-similaire) partiellement congestionnées. Nous traitons également le cas des équations multidimensionnelles avec une approche numérique. Dans la seconde partie de ce mémoire, nous nous intéressons à des modèles mathématiques qui s'écartent des équations de Navier-Stokes classiques afin de rendre compte de phénomènes plus "complexes" liés par exemple à l'hétérogénéité des fluides. On traite plus précisément le cas de suspensions granulaires et de milieux poreux, autour notamment des questions de transitions entre différents régimes d'écoulement au voisinage de la contrainte de congestion mais également, une nouvelle fois, autour de l'analyse de stabilité autour de profils d'ondes progressives
Postictal self‐removal of intracerebral electrodes during stereoelectroencephalography monitoring: A case series
No full textInternational audienceEpilepsy surgery remains the most effective treatment for focal drug-resistant epilepsy, and stereoelectroencephalography (SEEG) is increasingly used to define the epileptogenic-zone network (EZN) and guide curative or palliative interventions. While SEEG is considered a safe invasive procedure, adverse events arising during monitoring itself are rarely described. We report three exceptional cases of postictal self-removal of intracerebral electrodes during SEEG monitoring. Among 591 implanted patients between January 2000 and October 2025 at Timone Hospital, Marseille, three patients (0.5%) met the inclusion criteria. All were young right-handed men with normal neurocognitive development, focal drug-resistant epilepsy and no psychiatric comorbidity. Self-removal occurred during the postictal phase of spontaneous seizures-two following focal-to-bilateral tonic-clonic seizures and one after a focal impaired-awareness seizure-on the second day of monitoring under complete or partial antiseizure medication withdrawal. Postictal behavior was characterized by agitation, wandering, and, in two cases, resistive aggression when nursing staff attempted to intervene. None of the patients sustained neurological sequelae or significant cerebrovascular complications. EZN involved the temporal lobe in all cases. These observations illustrate that postictal confusion, particularly under medication withdrawal, may occasionally manifest as resistive behavior capable of causing self-harm by means of device manipulation. Awareness of this rare, but potentially hazardous phenomenon, identification of at-risk patients, and implementation of tailored preventive measures may help improve the safety of invasive epilepsy monitoring