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Mesozoic Pb-Zn hydrothermal veins in the Jebilet, Morocco: Constraints from mineralogy, fluid inclusions and stable isotope data
No full textInternational audienceThe Sarhlef, Bir N'Has, Bramram, and Bamega Pb-Zn vein deposits are hosted within the Carboniferous schistose series of the Jebilet Massif, Morocco. All four deposits share similar structural pattern and mineralization history. Early Variscan barren N-S quartz veins (Stage 1) crosscut the schist and are followed by E-W quartz-carbonate veins bearing Pb-Zn-(Cu) mineralization (Stage 2). Mineral paragenesis (stage 1) begins with pyrite, followed by minor arsenides (stage 1), associated with metamorphic carbonic to aqueous-carbonic fluids (7-18.4 wt% NaCl equivalent; 250° to >410°C), attributed to Variscan events in the Jebilet. The Pb-Zn ore stage (stage 2) comprises two polyphase episodes. The first episode begins with the deposition of carbonates (siderite-dolomite), followed by quartz (geodic comb then saccharoidal). The second episode is marked by ore deposition, with Fe-dolomite and minor calcite as gangue minerals. Barite crystallized locally (stage 2), followed by Fe-rich sphalerite, galena, and chalcopyrite. The ore stage is associated with aqueous brines (ore brines: ~9-27 wt% NaCl equivalent; 69°-212°C). Ore precipitation was likely driven by cooling and dilution of brines through mixing with recharge fluids.Stable carbon and oxygen isotope data from carbonates (stage 2) suggest that carbon was derived from fluids that interacted with organic-rich schist. The oxygen and hydrogen isotope compositions of the ore brines (δ¹⁸O: -1.8‰ to +2.4‰ ± 0.1‰ V-SMOW; δD: -60.4‰ V-SMOW) are typical of general basinal brines. Sulfur isotopes from galena and sphalerite (+3.1‰ to +12.9‰) suggest a sulfur source from Triassic evaporated seawater/Triassic evaporites for stage 2 (ore stage).The ore veins that crosscut post-Variscan microdiorite dikes are at least Mesozoic. We propose that the ore-forming brines originated from Triassic sedimentary and evaporitic sequences within Atlasic basins. Structural traps for Pb-Zn mineralization likely formed during Mesozoic extensional tectonics associated with the early rifting of the Atlantic Ocean.The Pb-Zn ore stage (stage 2) is genetically distinct from the earlier Variscan magmatic and metamorphic events (i.e. stage 1).</p
Spatial Distribution of European Grayling Reflects Longitudinal Temperature Patterns in a Swiss River
No full textInternational audienceMost salmonid populations are declining across their entire habitat range, partly because of large‐scale loss of crucial physical habitats. Alterations in river flow and temperature resulting from climate change are likely to further degrade habitat quality, particularly summer thermal conditions experienced by temperature‐sensitive fish species. Understanding how summer thermal conditions control the spatial distribution of ectotherms is thus central to helping project the consequences of climate change and develop management solutions. This study uses snorkelling fish surveys collected over 10 years and airborne thermal infrared (TIR) mapping of surface temperature acquired in 2022 to assess the relationship between European grayling distribution and thermal habitats along a 9‐km long reach of the Allondon River, Switzerland. Results show that all 3 grayling life stages (adults, sub‐adults and juveniles) respond negatively to elevated summer temperature, with distribution patterns highlighting thermal structuring effects on fish populations. The presence of two cooler reaches appears critical to the survival of the Allondon's declining grayling population, while the warmest reach that separates these habitats potentially acts as a thermal barrier during critical summer conditions. These results were used to guide local stakeholders towards short‐term and longer‐term actions to be taken on the river, which include: concerted trans‐national management to protect key upstream tributaries, tree planting to limit summer peak temperature and strategic protection of cold‐water patches that may act as thermal refuges during critical periods
TPUTrap: Hardware-Based USB Man-in-the-Middle Attack on Coral Edge TPU
No full textInternational audienceAI-based hardware accelerators, such as the Coral USB Accelerator, enable the use of AI in embedded systems without relying on the cloud, offering advantages like low latency, reduced power consumption, and enhanced privacy. It connects to the host via USB, which lacks encryption and authentication checks, raising security concerns in critical applications. This paper demonstrates a man-in-the-middle attack on the Coral USB Accelerator's USB interface, utilizing a Raspberry Pi 5 and a USB Proxy for real-time interception and manipulation of USB traffic. This approach successfully exfiltrated sensitive data and caused misclassification. Despite an added latency overhead, all attacks achieved 100% success, underscoring the need to address this security issue
Thomas Piketty’s Circle and the School of Inequality
No full textThis paper analyzes the emergence of a new school of economic thought, termed the "inequality school", which has successfully placed the distributional issue back at the heart of economic analysis and public debate. Led by Thomas Piketty, the school is a collective movement founded on the emerging international research network on inequality working at or collaborating with the World Inequality Lab (WIL). We present first the origins and foundations of this school as well as its members by distinguishing, through a bibliometric analysis, an "inner circle", the originators and leaders of the school, made up of Piketty, Saez, Alvaredo, Zucman and Chancel, and a "wider circle", made up of the collaborators and contributors of the ever-growing international network of the WIL. Then we identify its characteristics in terms of topic, methodology, values, and policy proposals, and highlight its contributions to economic science. Finally, we present the view of economics that members of the school share as a social, political, historical, and moral science and its democratic role
Exploration of Engagement and Interaction Patterns with Virtual vs Human Influencers: A 24-Month Comparison of Two Breton Personalities
No full textInternational audienceVirtual influencers, defined as computer-generated personas operated by creative teams, are reshaping influencer marketing, yet their reception compared to human influencers remains uncertain. While studies conducted in several countries suggest that novelty may stimulate engagement, evidence from the breton context, where authenticity and proximity are central evaluative criteria, remains limited. This exploratory study compares, over a 24month period, the performance of a virtual influencer and a human influencer with comparable audience size and thematic focus. Results show no statistically significant difference in engagement, including likes, comments and interaction rate. However, user interactions with the virtual influencer display slightly more polarized reactions, although negative comments remain extremely rare overall. These findings suggest that virtual influencers may integrate into the Breton digital landscape without clearly outperforming or underperforming human influencers. The study contributes to contextualizing virtual influencer effects in Europe and highlights the need for controlled experimental research to further examine the roles of authenticity and technological innovation.</div
Discussion de Rodney Benson et Julie Sedel, How Media Ownership Matters, Cambridge, Oxford University Press, 2025.
No full textCe livre publié en avril 2025 est le fruit d'une quinzaine d'années de travail, combinant une centaine d'entretiens semi-directifs approfondis, la collecte et la synthèse de multiples données sur les organisations médiatiques, leurs caractéristiques, propriétaires et stratégies, et des analyses de contenu des titres. La démarche comparative entre les Etats-Unis, la France et la Suède permet de situer de manière relative chaque titre dans un cadre national. Il comporte des apports méthodologiques nombreux, et présente un cadre théorique et des apports analytiques importants
Les enjeux et frontières des médias libres, indépendants et alternatifs locaux dans le Grand Ouest
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Engineering MgFe2O4 nanoparticles to enhance magnetic, optical, and dielectric performance
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Recursive properties of the characteristic polynomial of weighted lattices
No full textIn this paper, we describe properties of the characteristic polynomial of a weighted lattice and show that it has a recursive description, which we use to obtain results on the critical exponent of -polymatroids. We give a Critical Theorem for representable -polymatroids and we provide a lower bound on the critical exponent. We show that -polymatroids arising from certain families of rank-metric codes attain this lower bound
Convergence of higher derivatives of random polynomials with independent roots
No full textLet be a probability measure on , and let be the random polynomial whose zeros are sampled independently from . We study the asymptotic distribution of zeros of high-order derivatives of . We show that, for large classes of measures , the empirical distribution of zeros of the -th derivative converges back to for all derivative orders . This includes all discrete measures and a broad family of measures satisfying a mild dimension-nondegeneracy condition. We further establish a robustness result showing that, for arbitrary , even after adding a vanishing proportion of roots drawn from a dimension-nondegenerate perturbation, the derivative zero measures still converge back to . These results break the previously known logarithmic barrier on the order of differentiation and demonstrate that the limiting root distribution is preserved under differentiation of order growing nearly linearly with the degree