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Angeon, Valérie, Obertan, Paméla et Vairac, Muriel, (2025) « Quelles politiques publiques en faveur de l'agriculture guadeloupéenne ? Éléments de réflexion à partir des petites agricultures »
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R&R: Metric-guided Adversarial Sentence Generation
No full textAdversarial examples are helpful for analyzing and improving the robustness of text classifiers. Generating high-quality adversarial examples is a challenging task as it requires generating fluent adversarial sentences that are semantically similar to the original sentences and preserve the original labels, while causing the classifier to misclassify them. Existing methods prioritize misclassification by maximizing each perturbation's effectiveness at misleading a text classifier; thus, the generated adversarial examples fall short in terms of fluency and similarity. In this paper, we propose a rewrite and rollback (R&R) framework for adversarial attack. It improves the quality of adversarial examples by optimizing a critique score which combines the fluency, similarity, and misclassification metrics. R&R generates high-quality adversarial examples by allowing exploration of perturbations that do not have immediate impact on the misclassification metric but can improve fluency and similarity metrics. We evaluate our method on 5 representative datasets and 3 classifier architectures. Our method outperforms current state-of-the-art in attack success rate by +16.2%, +12.8%, and +14.0% on the classifiers respectively. Code is available at https: //github.com/DAI-Lab/fibbe
Pangeneric analyses reveal the divergent genome evolution and ecologies between morels and truffles in the Morchellaceae
No full textInternational audienceMorels are iconic macrofungi known for their culinary value and spring emergence. Molecular phylogenetic studies have hitherto failed to elucidate the evolution of the ecological lifestyles of true and false morels, impeding their capacity to resolve longstanding debates regarding the extent of their saprotrophy and the potential for biotrophic associations with plants. In this study, we examined the evolutionary history and molecular innovations of Morchellaceae by generating high-quality genomes from species encompassing all the major clades within this family. We used conserved single-copy orthologs to infer the evolutionary history of true and false morels and related truffles. The genome size, transposable element content, and polysaccharide-degrading enzyme gene content are consistent with an ectomycorrhizal lifestyle for the Morchellaceae truffles Leucangium carthusianum and Kalapuya brunnea, whereas the other clades, including all true morels (Morchella spp.), exhibited genomic signatures of saprotrophic habits characterized by a highly conserved set of genes encoding plant biomass-related degrading enzymes. Morchellaceae species were found to be predominantly heterothallic, with either the MAT1-1 or MAT1-2 loci; however, the occurrence of colocalized mating-type idiomorphs, indicative of homothallism, was observed in M. rufobrunnea, M. peruviana, L. carthusianum, and the outgroup taxon Gyromitra esculenta. This study revealed a wealth of largely undiscovered genomic traits, including saprotrophic potential within Morchellaceae and a lack of biotrophic markers, and contributes to our understanding of the intricate evolutionary trajectories of the modes of nutrition in soil fungi
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
A Jurassic Gondwanan origin with a Mesozoic vicariance and Cenozoic dispersals explains the biogeographic history of crown webspinners (Insecta: Embioptera)
No full textInternational audienceEmbioptera, commonly called webspinners, represent a small and understudied order of insects whose evolutionary history is poorly understood. To date, neither the timing of their origin, diversification, nor biogeographic history has been thoroughly investigated. In this study, we establish the groundwork for addressing these gaps by estimating divergence times for most extant webspinner lineages and reconstructing their biogeographic history using molecular and morphological datasets. Regardless of the sampling fractions (representing either the current or estimated diversity of webspinners), the clock models, and the inclusion or exclusion of morphological data, our divergence time estimates indicated that webspinners originated at around 280 Mya in the Permian, whereas the crown Embioptera appeared later, around 170 Mya in the Middle Jurassic. Our sensitivity analyses indicated that the divergence time estimates were robust to known biases in molecular dating analyses. With this new time-calibrated phylogenetic framework, we investigated the ancestral geographic origin of the order and reconstructed the historical biogeography of webspinners. Our analyses confirmed the expected Gondwanan origin of the crown group evident in the distribution of extant families, and a first radiation in Australia (Australembiidae). Our results suggested that the distribution of extant Embioptera results from a combination of vicariance, due to the break-up of Gondwana, and dispersal events following continental collisions during the Cenozoic. Through our analyses, we present a first comprehensive scenario for the diversification and origin of Embioptera, which provides testable hypotheses for further studies.</div
LUMA: A Benchmark Dataset for Learning from Uncertain and Multimodal Data
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Alkaloid Extract from Chimarrhis cymosa as a Corrosion Inhibitor for C38 Steel in 1M Hydrochloric Acid: Electrochemical and XPS Studies
No full textInternational audienceThe inhibitory effect of the alkaloid extract from Chimarrhis cymosa on C38 steel corrosion in 1M HCl was examined through electrochemical investigations. An inhibition efficiency of 90% was achieved with 200 mg/L of the alkaloid extract from Chimarrhis cymosa at 25 °C. Potentiodynamic polarization revealed that the extract acts as a mixed-type inhibitor. Nyquist plots showed that an increase in the concentration of the alkaloid extract from Chimarrhis cymosa led to an increase in charge-transfer resistance and a decrease in double-layer capacitance, resulting in enhanced inhibition efficiency. The adsorption of inhibitor molecules followed the Langmuir adsorption isotherm. XPS analysis confirmed the formation of an inhibitor layer on the steel surface containing the Chimarrhis cymosa alkaloidic extract
Manta-Ray: a study of the relationship between fluids and seismicity in the Lesser Antilles
No full textInternational audienceThe Lesser Antilles subduction zone is one of very few regions where old oceanic crust formed at slow spreading rates is being subducted. Crust accreted at slow spreading ridges differs from crust formed at higher rates, mainly in its higher content of material originating from the upper mantle, which is mostly hydrated to form serpentinites. The water stored in these serpentinites is released in the subduction process and then migrates upwards, towards the seafloor, where it forms fluid escape features, such as mud-volcanoes and pockmarks. Seismic reflection profiles from offshore Antigua and Barbuda image high amplitude seismic reflectors extending from the top of the downgoing crust roughly 15 km down into the mantle. They possibly originate from low-angle detachments related to exhumation of mantle material at the slow spreading Mid-Atlantic Ridge. As serpentinite rheology differs from that of basalt and gabbro, and because the amount of fluids from dewatering serpentinite is significantly higher than from mafic crust, the rheological properties of the plate interface and the margin are likely to influence slip behavior.During the Manta-Ray cruise in 2022, bathymetric and seismic data were acquired in the Lesser Antilles region with the objective to study the influence of subduction of this ultramafic basement on the tectonic deformation, fluid circulation and seismogenesis. At the accretionary prism fluid extrusion sites have been identified in the bathymetric data and their structures are finely imaged by high-resolution seismic data. Mud-volcano structures are linked to deeper faults and individual mud flows are imaged with a high enough a resolution to be described. In the region of the previously imaged deep reflectors, a 3D seismic experiment was conducted during which 23 deep sounding seismic profiles were acquired, crossing 75 ocean-bottom seismometers and using a 5000 cu-inch airgun array and a 6 km long seismic streamer. The extension of the reflectors east of the trench was proven and initial interpretation of the seismic data clearly shows the existence of several fault families dipping in different directions. In this area also numerous fluid extrusion features were identified which might have formed during accretion at the Mid-Atlantic ridge.During the LAVAS project, starting in 2025, we will further study the relationship between the hydration the downgoing plate and seismicity in the Lesser Antilles. In the scope of the project passive seismic data will be acquired using a sailing vessel along the different fluid extrusion sites to record signals from fluids leaving the seafloor. A submarine glider survey along these sites will help to identify possible methane accumulation in the water column. Satellite images will be used to identify natural hydrocarbons leaking from the seafloor and arriving at the sea surface. In an associated pedagogic project seismometers will be installed in schools on the islands of Guadeloupe and Saint Martin
Monitoring long-term bottom water temperature changes using fiber-optic sensing in submarine telecommunication cables
No full textInternational audienceLong-term environmental monitoring of the deep ocean environment is crucial for better understanding the feedback processes between the oceans and Earth’s climate in the face of global warming. However, obtaining in-situ observations from the deep seafloor is difficult and costly. Use of laser reflectometry in optical fibers using existing submarine telecommunication cables can help bridge this knowledge gap. We performed distributed fiber-optic sensing using the BOTDR (Brillouin Optical Time Domain Reflectometry) technique, which is sensitive to mechanical strain (elongation/ shortening) and temperature changes, on a network of commercially operating telecom cables connecting the islands of the Guadeloupe archipelago in water depths of 10 - 700 m. Monitoring at regular 6 month intervals over the past 2.5 years reveals a seasonally adjusted two-year temperature change (delta T) of about +1.5°C between 2022 and 2024 on the shallow carbonate platform (10 - 40 m water depth) south of Grande-Terre (Saint François), Guadeloupe. These sea-floor measurements are corroborated by satellite observations of the Sea-Surface-Temperature (SST) during the past three years, which document an identical temperature increase at the sea surface, in the same location (offshore Saint François). CTD measurements performed in 5 locations along the cables reveal well-mixed waters and no temperature stratification. A smaller temperature increase (0.2 - 1.0°C) is observed in deeper waters (300 - 700 m) between the islands over the same period (2022 - 2024). A new measurement campaign is planned in mid-March 2025 with BOTDR on the submarine cables and XBT (eXpendable Bathy Thermograph) measurements at sea. Together with an additional field campaign performed (at a 3-month interval) in Sept. 2024 (during the maximum annual water temperature) the new campaign (performed during the minimum annual temperature and again at a 3-month interval) will fully constrain the seasonal variations in water temperature. These results can open the path for widespread use of submarine cables for long-term environmental monitoring of the seafloor