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Refeeding with different levels of dietary carbohydrate modulates epigenetic stability through global DNA (de)methylation and histone modifications in juvenile and adult Nile tilapia ( Oreochromis niloticus )
No full textInternational audienceThe Nile tilapia (Oreochromis niloticus) exhibits a strong metabolic response to dietary carbohydrates (CHO). Short-term refeeding after fasting with a high-carbohydrate (HC) diet has been shown to modulate CHO metabolism, but the role of epigenetic regulation in this response remains unclear. This study investigated how short-term refeeding with either a HC [639.2 g kg -1 diet]/low-protein [164.9 g kg -1 diet] (HC/LP) diet or a low-CHO [47.4 g kg -1 diet]/high-protein [607.9 g kg -1 diet] (LC/HP) diet influences global DNA methylation and demethylation, histone modifications, and mRNA levels of epigenetic regulators in the liver and muscle of juvenile and adult Nile tilapia. Following a 4-day fasting period, fish were refed for 4 days with either HC/LP or LC/HP diets. Compared to the fasted state, refeeding with either diet altered epigenetic markers by: (1) decreasing hepatic global DNA 5-mC oxidative derivatives-5-hmdC in juveniles, and both 5-hmdC and 5-cadC in adults; (2) inducing histone hypermethylation and/or hyperacetylation -H3K9ac (hepatic) and H3K36me3 (muscular) in juveniles, and H3K9me3 and H3K9ac (muscular) in adults; and (3) promoting expression of enzymes related to DNA hypermethylation (upregulated dnmt, downregulated tet) and histone hypermethylation/ acetylation (upregulated setd1b, kmt2, suv39h1b; downregulated kdm4, sirt5). Dietspecific effects included hepatic H3K36 hypomethylation and H3K9 hypoacetylation in juveniles fed HC/LP, accompanied by upregulation of kdm4b, kdm4c, and sirt5. In adults, HC/LP refeeding induced muscular DNA hypomethylation and H3K9 hypoacetylation, associated with upregulation of tet, sirt2, and sirt5. Refeeding following fasting induced histone hypermethylation and/or hyperacetylation, while HC refeeding was particularly associated with muscular global DNA hypomethylation and histone hypoacetylation/ methylation. HIGHLIGHTS• Understanding epigenetic responses to diet can inform sustainable aquaculture practices by optimizing feed composition for health, performance, and adaptability. • Short-term refeeding with diets varying in carbohydrate and protein levels modulates key epigenetic mechanisms -including DNA methylation and histone modificationsin Nile tilapia. • High-carbohydrate/low-protein (HC/LP) refeeding induces tissue-specific hypomethylation and hypoacetylation, particularly in muscle, which may have long-term implications for metabolic health and growth. • Epigenetic responses to refeeding differ between life stages, emphasizing the need for age-specific feeding strategies in aquaculture.• Nutritional programming through short-term dietary interventions may influence gene regulation beyond immediate metabolic effects, supporting precision feeding approaches.</div
Counting the Stakes: A Reassessment of Vlad III Dracula’s Practice of Collective Impalements in Fifteenth-Century South-eastern Europe
No full textInternational audienceAbstract Dubbed ‘the Impaler’ by his contemporaries, Vlad III Dracula ( c . 1431–76), was accused of the slaughter of between 40,000 and 100,000 individuals, 20,000 of them allegedly impaled at the Wallachian capital Targovişte. Although historians have often considered these figures inflated, none of the numerous studies dedicated to the voivode of Wallachia have undertaken a methodical evaluation of the extent of this exaggeration. This article takes up this historiographical challenge by examining all available documentation. In so doing, it provides a full reassessment of the practice of impalement in fifteenth-century south-eastern Europe. Contrary to assumptions of previous scholarship, Vlad’s use of impalement was influenced simultaneously by pre-existing Hungarian and Ottoman practices. Quantitative analysis shows that only 7–10 per cent of the impalements claimed by sources can be considered plausible and proposes a new data-driven estimation of Vlad’s impaled victims. Finally, a comparison with other rulers shows that, while Vlad ordered collective impalements more frequently, the average number of victims per impalement was similar to that elsewhere in south-eastern Europe
Numerical modelling of thermoplastic CO2 assisted extrusion foaming: Exploring the process-microstructure relationship
No full textInternational audienceThis study presents a comprehensive numerical modeling approach for thermoplastic foams processing, produced via supercritical CO₂-assisted extrusion foaming. The model focuses on the nucleation and growth of bubbles within the polymer matrix, employing the influence volume approach to simulate these dynamics. Key phenomena such as gas diffusion, nucleation rate, bubble growth, and the evolution of influence and non-influence volumes are captured to predict foam microstructure and cellular density. Results highlight the model’s capability to predict equilibrium bubble sizes ranging from micrometers to hundreds of micrometers, offering insights into foam behavior and microstructure control. The final size distribution will be used to create on Paraview® the microstructure that will be compared to experimental observations in the future
Mobilité et migration dans l'espace francophone. Synthèse et conclusion du Colloque international
No full textInternational audienceLe colloque international intitulé «Mobilité et Migration dans l’espace francophone» s’est tenu les 27 et 28 mars 2025 à la Villa Noël, à Bucarest, dans un format hybride, organisé par les Chaires Senghor de l’Université de Bucarest 2, de l’Université de Sciences Agronomiques et de Médecine Vétérinaire de Bucarest (USAMV), de l’Université de Lyon 3 et de l’Université de Moncton en partenariat avec l’Institut d’Études Africaines (ISA), le Centre Régional Francophone d’Études Avancées en Sciences Sociales (CEREFREA) et l’Institut de Recherche de l’Université de Bucarest (ICUB) et le réseau international Metropolis 3. L’événement a réuni chercheur·e·s, enseignant·e·s, étudiant·e·s, représentant·e·s d’institutions publiques et diplomatiques autour d’un thème essentiel du monde contemporain.Ce colloque a essayé de répondre à une série de questions-clés et a proposé une réflexion profonde sur le rôle de la langue partagée comme levier pour comprendre, repenser et agir sur les dynamiques de mobilité et de migration. La francophonie y a été pensée non seulement comme cadre linguistique, mais comme espace de circulation des savoirs, des mémoires, des résistances et des solidarités
Incubation Experiments, Observations, and Modeling Highlight the Key Role of Dimethylmercury on Seawater Methylmercury Distributions
No full textInternational audienceThe origin of the bioaccumulative neurotoxin methylmercury (MeHg) in the ocean remains elusive. The current paradigm suggests that microbial methylation of inorganic Hg within the oceanic water column produces monomethylmercury (MMHg) and potentially dimethylmercury (DMHg). Reaction rates and main drivers governing MeHg levels (sum of MMHg and DMHg) are poorly constrained. We conducted ambient Hg species measurements and enriched isotopic tracer experiments in waters of two contrasting marine environments, the oligotrophic Mediterranean Sea (MED) and the mesotrophic Atlantic Ocean (ATL). Maximum subsurface MeHg levels were ~2 times higher in the MED compared to the ATL, essentially driven by higher DMHg concentrations (0.45 ± 0.06 vs 0.16 ± 0.02 pM).Methylation was only detectable in unfiltered subsurface waters and presumably biotically driven. The highest methylation rate (MMHg to DMHg) was observed in subsurface MED waters while reduction and demethylation rates were highest in surface waters of both environments. Experimental reaction rates and the potential microbial activity (based on 16S rDNA) aligned with ambient Hg species distributions.Assuming high DMHg stability and applying our fast experimental DMHg formation rates, a newly developed 1D water column model (MED) successfully reproduced MeHg species distribution, suggesting DMHg plays a key role in the global marine Hg cycle
Onésime Reclus et la francophonie au risque de la colonisation
No full textInternational audienceQuand le nom d’Onésime Reclus est mentionné en tant que créateur du terme de francophonie, il n’est pas rare de lui associer aussi celui de colonialisme. S’il est exact qu’Onésime Reclus fut un des chantres de l’expansion coloniale française, faut-il pour autant considérer que l’idée de francophonie soit un avatar colonialiste
On an eigenvalue problem associated with mixed operators under mixed boundary conditions
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The Poetics of Manipulation in Mountain Path by Harriette Simpson Arnow
No full textInternational audienceIn Mountain Path (1936), Harriette Simpson Arnow (1908-1986) meticulously explores the Kentucky hill life in the 1920’s and its coarse, uneducated people endowed with a visceral attachment to their rugged land and imbued with strong family and communal ties. The story begins in a conventional way: an 18-year-old student Louisa Sheridan, reluctantly accepts a job as a teacher as she needs money to further studies. She is assigned to an inhospitable region in the Cumberland mountains to educate illiterate children. For a whole year, she lives with the Lee Buck and Cory Calhoun’s (Cal) family, and schools - in precarious material conditions - two of their children and some others living in the surrounding area. Nevertheless, she learns as much from them as she teaches them, and she gradually discovers their habits but also experiences destitution and insecurity due to feuds and rancor as the seasons go by. An interconnected web of extended family and neighbors strengthens the narrative as their lives unfold, interspersed with periods of fear and superstition. Many critics and readers have labeled this chronicle an autobiographical novel since the young Harriette Simpson had herself been a teacher in remote lands of Appalachia at the same age as her main character. Nevertheless, beneath the veneer of the exploration of a milieu lies an underlying complexity that will be scrutinized in this paper. Within the narrative, it encompasses a protean strategy of manipulation which surreptitiously open the way to an unexpected, but conspicuous perspective with multiple interpretations. Arnow portrays with strength and conviction these indigent families’ harsh life, their narrow-mindedness, their fatalistic acceptance of danger, but also their courage and dignity in the face of adversity. Far removed from the modern world, they speak a vernacular language and perpetuate their habits - household and farm chores, moonshining, hunting - in a hard-to-reach region. Nonetheless, the poetics of manipulation covertly transcends the narrative and reverberates in the writer’s convictions. Although it received rave reviews for a first novel, Mountain Path was described as a regionalist fiction with a classic trope that exposed—like so many others before it—the experiences of young educators in the poor, rural communities of Appalachia, and it was quickly relegated to oblivion. It is high time critics and readers reconsidered this engaging dense fabric of life that defies schematization, commands respect, and clearly substantiates Harriette Simpson Arnow’s talent and mastery in writing fiction
Investigating Interactions Between Fish and Offshore Wind Farms Using Acoustic Telemetry
No full textInternational audienceIn France, the increasing demand for decarbonized energy production has led to a rapid expansion ofoffshore wind farm (OWF) deployment, with over 15 projects currently in progress. The introduction of these anthropogenic structures in the marine environment is likely to influence space use and habitat connectivity of fish. OWFs can act as artificial reefs for certain fish communities with species exhibiting high residency and/or site fidelity patterns for these new habitats. On the other hand, pressures generated by OWF, such as noise emissions, may repel certain species and modify movement and migration behaviour. Considering the ecological functions and socio-economic importance of fish communities, these effects need to be assessed through comprehensive and long-termmonitoring. The collaborative FISHOWF project (2021-2024) used acoustic telemetry to identify how mobile fish species use and connect different habitats across OWF development areas in the Channel, Atlantic and mediterranean Sea. This monitoring method involves using sound-emitting tags and underwater receivers to track fish movements. This project relied on dedicated receiver arrays deployed within 4 OWF, combined with the region-wide acoustic telemetry networks FISHINTEL (Channel), CONNECT-MED & RESMED (Mediterranean) to monitor over 400 fish/crustaceans (including sea bass, pollack, lobster, sharks and rays). Protocols using acoustic telemetry at different spatial scales were tested, including a fine-scale positioning approach to track movement behaviour near anOWF structure. Key results include the identification of important existing habitats for several species in OWF underconstruction, temporary residency and site fidelity of two elasmobranch species within an operational OWF, anddetections within OWF areas of several migratory species travelling across the Channel.FISHOWF demonstrated the relevance of using acoustic telemetry at multiple spatial scales to identify and evaluatespecific effects of OWF and their grid connection on fish. Results contribute to improving ecological knowledge on monitored species, to better assess habitat modifications induced by OWF from the seafloor to the surface, and to better understand the ecological role of these artificial structures (e.g. refuge, essential habitat, ecological traps).The follow-up project FISHOWF+ (2024-2027) will maintain and expand this acoustic telemetry monitoring to up to6 OWF (fixed-bottom and floating OWF) and aims to: • optimize the acoustic telemetry network within the OWF& development zones to characterise fish aggregation and reef effect at different spatial scales (e.g. Substation vsOWF scale) • assess in situ behaviour of electrosensitive species near a substation & dynamic cable of a floating turbine and provide insights into potential electromagnetic field effects • examine how OWF construction activities impact fish habitat use• address knowledge gaps on regional connectivity at EUscale and the ecological role of OWFThe ongoing and future efforts of the FISHOWF and FISHOWF+ projects underscore the importance of comprehensive monitoring and research to understand the ecological impacts of offshore wind farms. By leveragingadvanced technologies like acoustic telemetry, these projects aim to provide valuable insights into the interactions between marine life and OWFs, ultimately guiding sustainable development and management practices that balance energy production with marine conservation. Findings will not only enhance scientific understanding but also inform policy decisions, ensuring that the expansion of renewable energy infrastructure integrates and promotes marine ecosystem health