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Un “penser” à l’infinitif : l’arrière-plan théorique, scolaire et polémique de la définition du Bien comme φρονεῖν chez Numénius
No full textInternational audienc
Our Gothic, more beautiful than yours: Erwin Panofsky and Gothic architecture, or the logic of re-located work
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Lorenzo Respighi (1824-1889), geodesist
No full textInternational audienceAstronomy and geodesy are now distinct activities but, throughout the 19th Century (and until the First World War), they were indeed part of the observatory astronomical sciences which also included celestial mechanic, table’s computation, cartography, meteorology, metrology, instrument development and even what would later be called the Earth sciences. Astronomer’s nineteenth-century practical activities are generally passed through silence respect to the proper observation of celestial bodies (although there is actually a revival for the conception and real utilization of astronomical ta-bles): this is the case for Lorenzo Respighi (1824-1889), an Italian astronomer who lived in the turbulent political period of the Italian Risorgimento and the progressive unification of the Italian peninsula. This paper focus to Respighi’s geodetic engagement and his original achievements in this domain. Firstly, some milestones in Respighi's formation and career are re-called. A second and largely part concerns on Respighi original researches in the do-main of geodesy. More generally, this article is a work in progress whose aim is the study of Italian geodesy in the pre- and post-unification period
Breaking the species barrier: recurrent genomic introgressions from very distant lineages in a ciliate
No full textInternational audienceThe process of speciation, through which two reproductively isolated species emerge from an ancestral population, is often gradual, including a period during which gene flow still occurs, and hence speciation remains reversible. However, if isolation persists, the progressive accumulation of genetic incompatibilities ultimately locks the speciation process, reaching the point where hybrid offspring are inviable or sterile. In plants and animals, the establishment of species barriers is quite rapid: beyond a net genetic divergence of 0.02 substitutions per synonymous site, interspecific introgressions become extremely rare. Here we report that in ciliates, species barriers can be broken despite huge genetic divergence. We show that the genome of Paramecium sonneborni contains hundreds of DNA segments that were acquired by recurrent horizontal transfers from multiple very distant lineages (synonymous divergence ~1 substitution/site). These segments approach the size of full-length chromosomes, which indicates that they were introgressed by inter-specific mating. These data show that in the ancestry of P. sonneborni, hybridization events with highly divergent species occurred repeatedly and led to viable and fertile offspring. We propose that this unexpected promiscuous sexual behavior is made possible by the fact that paramecia separate somatic and germline functions in two types of nuclei: the elimination of non-self DNA fragments during the development of the somatic genome allows individuals of a species to remain phenotypically the same, despite recurrent genetic flow from distant species into their germline
Demand response control structure in imperfectly competitive power markets: Independent or integrated?
No full textInternational audienceThis article investigates different types of actors controlling demand response (DR) operations under Cournot competition. Analytical results linking shiftable load level, market equilibrium, and welfare are obtained for DR operated either by an independent aggregator (price-taker or price-maker), by end-consumers’ suppliers, or within the portfolio of generators. An application to a 2035 French power system with detailed flexible appliances constraints is also proposed. Results show that supplier-integrated DR yields the greatest price reductions and lowest shiftable load withholding, while DR integrated with baseload producers has the weakest effects on prices and may worsen welfare losses compared to a perfectly competitive market. While DR deployment consistently improves welfare and lowers prices, the extent depends on the control structure. Independent aggregation and supplier integration deliver similar welfare gains but shift surplus toward consumers, whereas integration within generators results in up to a 6€/MWh higher producer surplus compared to the other structures. Policy implications highlight the importance of DR deployment overall but caution against DR integration exclusively within baseload generators’ portfolios due to limited market benefits
« La proschrèsis de Numénius : une lecture controuvée, mais utile, de Timée, 39 e 7-9 », dans S. van der Meeren (dir.), Les contresens féconds dans l’exégèse antique, Rennes, PUR, 2026.
No full textInternational audienceNuménius définit la relation entre ses trois dieux ou intellects en termes de proschrèsis. La notion apparaît dans un témoignage de Proclus (30 T = fr. 22 dP). Elle désigne une « utilisation supplémentaire ou subsidiaire » par laquelle l’un des dieux en utiliserait un autre pour réaliser un acte, en l’occurrence de pensée. Le caractère abscons de cette notion a suscité les débats. Certains ont fini par juger qu’elle constituait une doctrine caractéristique de l’auteur. Or elle semble moins représenter un concept nouveau que le résultat d’une trouvaille exégétique. Numénius s’en sert pour expliquer sa lecture controuvée de Timée, 39 e 7-9. Elle lui permet de libérer son premier dieu et intellect à la fois des formes et de l’intellection pour le laisser être un pur penser (phronein). Il le distingue des deux intellects suivants, dont l’un se charge de l’intellection (noein), l’autre de la pensée discursive (dianoeisthai). L’article explicite cette interprétation et montre comment elle permet de situer Numénius à l’origine de l’application, chez ses successeurs, du terme to autozôion (« le Vivant lui-même ») à « ce qui est vivant » (ho esti zôion) en Timée, 38 e 8. Ce « vivant » devient une figure hypostasiée, identifiable, chez Numénius, au premier dieu, intellect et principe
Spatio‐temporal patterns and risk factors of wild boar–pig farm contact across Europe
No full textInternational audienceDiseases circulating at the wild–domestic animal interface are increasingly difficult to control due to human encroachment into wildlife habitats. Understanding the factors driving wild animals to visit livestock farms is crucial for reducing the risk of disease outbreaks with severe economic and social consequences. In this study, we quantified the contact rate at the wild boar–domestic pig interface across Europe using a large‐scale dataset of wild boar GPS tracking and domestic pig farm geolocations. We estimated wild boar contact rate with pig farms at hourly and monthly scales and analysed the influence of environmental, wild boar‐ and farm‐related variables. Across 187 tracked wild boars and 457 pig farms, we detected 3322 contact events, with a highly skewed contact distribution: only 5% of wild boars and 1% of farms accounted for 50% of all events. On average, each wild boar had 1.59 contacts per month with a given farm (95% CI: 1.33–1.85) and 2.58 contacts per month when considering all farms located within its monthly home range (95% CI: 1.62–3.53). Seasonal variation differed between sexes, with a bimodal distribution for males with contact rates peaking in March and August–September, and a slight increase in contact rate throughout winter for females. Monthly contact rate increased with forest cover, human footprint, wild boar population density and individual proximity to pig farms. Farms with more built infrastructure faced fewer contacts, and larger farms had higher contact rates. Contacts occurred mostly after sunset and around sunrise. Synthesis and applications . Our results highlight the need to incorporate wild boar spatio‐temporal behaviour and farm context into strategies aimed at reducing contact at the wild–domestic pig interface. While physical barriers and avoiding unintentional feeding remain essential, targeted measures during high‐risk periods, such as night‐time surveillance in summer and autumn, especially around large farms in wooded landscapes or areas with high wild boar density, could help reduce contact occurrence
The importance of sleep in animals and its potential vulnerability to climate change
No full textInternational audienceSleep is a universal behavior across animals, critical for physiological homeostasis, cognitive function, and development. Throughout evolution, animals have adapted to environmental changes, but current rapid climate change may threaten sleep patterns adapted to specific ecological niches through rising temperatures, shifting precipitation, and extreme weather. Despite the importance of sleep, climate change–driven sleep disruptions are not well-considered. We introduce the importance of sleep and examine how climate change affects sleep in different biogeographical zones (polar, tropical, dry/arid, and marine and coastal regions), highlighting region-specific vulnerabilities. Furthermore, we discuss the cascading effects of sleep disruption on species interactions, population dynamics, and ecosystem functioning. We emphasize the need for long-term ecological studies, advances in sleep-measurement technologies in free-living animals, and the integration of sleep ecology into conservation strategies. Future priorities include assessing variability within and between individuals, the fitness costs of sleep loss, and the potential for evolutionary adaptation
Detection of an anadromous fish demonstrates the potential of passive environmental DNA sampling for monitoring migratory fish
No full textPassive environmental DNA sampling (PEDS) is a new method that is increasingly used to inventory aquatic biodiversity through environmental DNA (eDNA). In contrast to active filtration (AF) to obtain eDNA, which can require batteries and electronics to actively pump water, PEDS involves simply exposing a material to water to passively collect eDNA particles from the environment. As the duration of sampling takes place over several days, this could detect species missed during active filtration. However, its potential to spatially and temporally detect mobile fauna has been little investigated to date. To explore this, this study evaluated its potential to monitor a migratory fish, the first study of this kind. After a preliminary experiment in a fish pass equipped with cameras to validate our workflow, we monitored in the field the upstream migration of an anadromous fish, the twaite shad Alosa agone. The field study was carried out across 25 km of the Aude River in the south of France over a period of seven weeks (February to April 2025). This monitoring period was chosen based on historical direct observations to cover an initial phase without twaite shad in the river, followed by the first adult arrivals, and subsequent confirmed observations in the spawning area. Using a metabarcoding approach with 12S rRNA MiFish-U primers, we successfully detected twaite shad both with PEDS (22%) and AF (10%), finding no significant difference between the methods. At the ecological level, no clear upstream migration pattern could be characterized as no significant effects of environmental covariates (temperature, water flow) were found on twaite shad detection. Nonetheless, these results are encouraging for PEDS monitoring of fish species both spatially and temporally, especially considering that migration of this fish was incredibly low in the study area in 2025 (3 spawning events recorded in 2025 compared to a mean of 314 per year between 2021 and 2024). Moreover, our occupancy model indicates that the sampling design could be further optimized for future monitoring by increasing the number of PEDS replicates (to up to 11). The low cost, ease of deployment and effectiveness of passive samplers (for mobile species, in turbid waters, etc.) make these tools an additional asset for eDNA biodiversity surveys in a variety of environments
