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High temporal variability not trend dominates Mediterranean precipitation
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La mémoire du risque cyclonique à Mayotte : de la mémoire habitante à la mémoire paysagère, le cas de Kamisy (1984) et Feliksa (1985)
No full textInternational audienceDans cette communication nous reviendrons sur le concept de mémoire du risque que nous développerons au prisme d’une recherche menée auprès des habitants de Mayotte et de l’exploitation de la documentation archivistique. Nous proposerons une discussion sur le concept de mémoire du risque et de son élargissement à des objets autre que les éléments transmis par le témoignage ou les archives en questionnant la place des paysages comme objet produit par les sociétés et porteur en lui-même d’une mémoire à valoriser dans le cadre de stratégie de prévention des risques
Disentangling Current and Latent Dimensions of Vulnerability in Social-Ecological Systems
No full textInternational audienceThe effects of global environmental change, already tangible worldwide, are projected to increase in the future, putting at further risk ecosystems and societies. Vulnerability assessments have become widely used to study how social-ecological systems are exposed and resilient to climate change or cumulative stressors. Many of these assessments, however, implicitly add up entangled current and latent dimensions of vulnerability. In this chapter, we argue that conceptualizing the difference between current and latent, as well as present and future dimensions of vulnerability, would benefit vulnerability assessments as time represents both a barrier and a lever to adaptation. Using published literature, we assess the links between past, present, and future vulnerability, propose a definition of current and latent dimensions of vulnerability and then discuss practical methods and indicators to assess them
Drifters, Steamboat Pilots, Raftsmen, and Failing Epics: Twain’s Riverine Motifs as Narrative Resistance.
No full textInternational audiencePrimary objective: This article argues that Twain replaces the epic logic of the American Frontier with a counter-geography of the river—a space defined by drift, uncertainty, and suspension, where the Mississippi resists technical, narrative, and ideological attempts at control. By privileging fluidity over mastery and motion over arrival, Twain constructs a counter-mythology of America that destabilizes traditional heroic frameworks and reveals the fragility of utopias grounded in conquest.1) Scientific interest: Adventures of Huckleberry Finn is often described as the foundational work of American literature; Hemingway famously claimed that “all modern American literature comes from this one book.” This reputation rests largely on the classic interpretation of Huck as a “New Adam,” the quintessential American figure who turns his back on a corrupt world and heads toward “the Territory” in search of renewal. This article proposes a different approach: rather than following Huck toward the Frontier, it turns back to the river—the raft, the currents, the steamboats, and the drifting motion that structure the novel.2) Relevance and scholarly contribution: The river functions as a principle of counter-movement. Whereas the Frontier offers a utopia grounded in mastery—claiming new land, securing a return to imagined innocence—the river proposes a utopia of drift: moving without dominating, surrendering rather than controlling, embracing uncertainty rather than pursuing a fixed goal. The Mississippi becomes a space where Twain resists major American myths of progress, conquest, and heroic self-making. It is a threshold space in which both Huck and the reader dwell momentarily in suspended innocence before the inevitable passage into experience. This “threshold aesthetic,” in which innocence persists just before history turns toward experience, belongs to what Richard Gray has defined as the long-standing pattern in American cultural imagination. Twain participates in this tradition while simultaneously unsettling it, offering a narrative where movement does not guarantee progress and where utopia emerges not from mastery, but from relinquishment.Publié par les éditions Ellipses en vue de la préparation à l’agrégation d’anglais 2026, l’article « Drifters, Steamboat Pilots, Raftsmen, and Failing Epics: Twain’s Riverine Motifs as Narrative Resistance » propose une relecture de la matérialité fluviale et nautique du récit (le fleuve, le radeau, le bateau à vapeur), envisagée non comme simple décor, mais comme principe narratif actif et résistant.Pertinence et contribution scientifique : 1) Sur le plan critique, je propose une relecture de Huckleberry Finn à partir des motifs de la dérive, du flottement et de la résistance à la maîtrise, en dialogue étroit avec les écrits autobiographiques et métapoétiques de Mark Twain (Life on the Mississippi, Two Ways of Seeing a River). Le fleuve et le radeau y sont analysés comme des espaces liminaux qui suspendent les logiques de domination sociale, raciale, technologique et narrative. 2) Sur le plan théorique, l’article s’inscrit à la croisée de la critique pastorale (Leo Marx), des études sur le mythe américain (frontière, progrès, épopée), et d’une réflexion narratologique sur la résistance à l’unité, à la clôture et à la finalité. Il montre que ce que la critique a souvent qualifié « d’incohérences » ou de « faiblesses structurelles » du roman peut être relu comme un choix poétique et politique délibéré, aligné sur une esthétique de la fluidité et de l’errance. 3) Sur le plan des études américaines, l’analyse permet de repenser la place du roman dans la tradition nationale : plutôt que d’annoncer un héroïsme westward ou une sortie vers le « Territory », Twain ferait du fleuve un contre-modèle utopique fragile, fondé non sur la conquête, mais sur la suspension, le renoncement à la maîtrise et la défiance envers les grands récits (épiques, romantiques ou technocratiques). 4) Enfin, l’article s’inscrit dans une réflexion plus large sur les figures de mobilité marginale (drifters, raftsmen, faux aristocrates, pilotes déchus), en continuité avec les recherches sur les formes de masculinité instables, liminaires ou déclassées dans la littérature américaine. À ce titre, il contribue à la fois au champ des Twain studies et à une interrogation plus générale sur les modalités de résistance narrative au sein du canon
Integrative Taxonomy and Geographical Distribution of Antennella billardi and Antennella varians (Cnidaria, Hydrozoa) in the Southwestern Indian Ocean
No full textInternational audienceHydroids have historically been described by morphology, but recent genetic studies have highlighted numerous taxonomic problems. In the genus Antennella , two species, Antennella varians and Antennella billardi (formerly A. balei ), were until recently considered synonyms. We sampled colonies of these two species in the southwestern Indian Ocean at mesophotic depths (between 30 and 150 m): A. varians on Mayotte Island and A. billardi on Réunion Island. This study uses an integrative taxonomic approach, combining morphological measurements, DNA barcoding, observations of biological characters and geographical distributions that complement current knowledge. The barcoding results confirmed the distinction between the two species with both mitochondrial and nuclear genes. Morphological measurements provided two main and robust characters to distinguish them: the length of the first pair of nematothecae and the length of their apophysis. Surprisingly, A. billardi showed synchrony of sexual and vegetative reproduction, as two different types of female gonotheca content were observed: oocytes and frustules. These results highlight the need to combine complementary approaches in order to describe biodiversity more accurately and continue to discover the peculiarities of the animal kingdom, especially in hard‐to‐reach areas, such as the mesophotic zone
LUMA: A Benchmark Dataset for Learning from Uncertain and Multimodal Data
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Exploring the skin Microbiome of free-ranging Dugong dugon in new Caledonia
No full textInternational audienceThe skin microbiome plays a vital role in the health of marine mammals, serving as a protective barrier and interacting with the host’s immune system. There is limited knowledge about the skin microbiome of dugongs (Dugong dugon), a vulnerable species with declining groups due to anthropogenic threats. This study provides the first comprehensive analysis of the skin microbiome of free-ranging dugongs in New Caledonia using 16S rRNA gene sequencing. The results show that the dominant bacterial phyla on dugong skin are Pseudomonadota, Bacteroidota, and Campylobacterota. Within Bacteroidota, the genus Tenacibaculum - which includes known opportunistic pathogens - was notably the most relatively abundant. Among Pseudomonadota, Psychrobacter was the most dominant genus; although it may contribute to maintaining skin homeostasis, its overrepresentation has been associated with compromised health in other marine mammals. Additionally, the genera Arcobacter and Campylobacter, both belonging to Campylobacterota, include zoonotic species and may warrant future monitoring in dugong populations. Distinct variations were noted between sex, with females predominantly hosting Psychrobacter, while males had higher abundances of Kinneretia and Dasania. Our results align with emerging evidence that marine mammal skin microbiota are shaped by host-specific traits, environmental conditions, and geographic context. These findings provide a baseline for future research on the skin microbiome of dugongs and highlight potential indicators of health and disease in this species
The Memristive Implementation of the Hippocampus: A Hypothesis
No full textInternational audienceWe present a hippocampus-inspired neuromorphic system based on a stochastic polycrystalline nano-fiber mesh. This system takes advantage of the inherent randomness of the material structure to create a dynamically evolving connectivity pattern that mimics the probabilistic nature of biological synaptic networks. The memristive architecture is based on polycrystalline copper-based materials derived from acetylsalicylic acid (aspirin). Three different compounds were obtained by adding axial ligands to [Cu(asp)]: benzimidazole (bimi), pyridine (py), and 1,4-diazabicyclo[2.2.2]octane (DABCO). The results showed that the memristive properties of devices based on copper complexes can be modulated with various axial ligands. Moreover, theoretical analysis predicts the possibility of mimicking hippocampal architecture via co-crystallization of hydrophobic organic molecular semiconductors with selected copper complexes. Additionally, we demonstrated that controlling the crystallization temperature and solvent composition allows precise tuning of resistive switching in methylammonium lead iodide perovskites. Together, these approaches provide a versatile foundation for implementing dynamic, brain-like memory functions in hardware
Groundwater monitoring and modelling, a crucial challenge in a semi-arid and poorly documented region affected by a high poverty rate (southern Madagascar)
No full textInternational audienceGroundwater plays a key role in providing access to drinking water, especially in semi-arid regions where surface water is scarce or absent for much of the year. In the semi-arid region of southern Madagascar, approximately 2,000,000 people face one of the highest poverty rates in the world, making them particularly vulnerable to climatic hazards. As a result, describing and predicting groundwater dynamics is essential to understand and anticipate drought-related humanitarian crises. How to estimate groundwater recharge in a such poorly documented area?Our work consisted of comparing two complementary approaches for estimating groundwater recharge. First, the Groundwater Resource Observatory for Southwestern Madagascar was established in 2014 in difficult logistical settings to monitor piezometric level from 16 boreholes located in various hydrogeological systems. This observatory provides long-term piezometric time series at an hourly time step, which were used to calculate recharge following the Water Table Fluctuation (WTF) Method.Second, a spatial hydrology approach was developed to estimate potential recharge using precipitation and evapotranspiration global products based on remote sensing data. The two approaches were compared, revealing the potential and limits of both. Based on these results, we compare our findings with health outcomes, offering new avenues for research
Characterizing the extent of the oceanic 60–150 m deep mesophotic zone in Tuamotu-Gambier Archipelago atolls using multibeam bathymetry and geomorphology data
No full textInternational audienceThe mesophotic zone between 60 and 150 m of water depth is of increasing interest to science and management considering its biological communities, the species physiology, and the biological and physical connections with the shallower domain at a variety of ecological and evolutionary time scales. For tropical coral reefs, it is believed that the extent of mesophotic coral ecosystems (MCEs) can be much larger than their shallow coral reef counterparts, prompting arguments on which areas conservation funds should be devoted to. In French Polynesia, using a compilation of multibeam bathymetric data collected on 17 Tuamotu-Gambier atolls, and an atoll geomorphology database for 69 atolls, we estimated that the oceanic 60–150 m deep mesophotic zone of 69 atolls spread across 1700 × 800 km of oceanic territory only covers 349 km2. This mesophotic zone is very steep. Average of slope minimums and maximums for the 17 atolls was 27 and 73 degrees, respectively. The 60–150 m surface area represents only 3% of the extent of the lagoons for the same 69 atolls. The consequences of these findings for conservation decisions are multiple and discussed, and future MCE work in Tuamotu-Gambier is envisioned