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The site of Notarchirico (Venosa Basin, Italy) and the hominin behavior in the Middle Pleistocene: New insights from taphonomy and spatial archaeology
No full textInternational audienceThe early Middle Pleistocene is characterized by a significant turnover in the fauna across Europe, creating new niches and new subsistence opportunities for hominin populations. Open-air sites provide a unique opportunity to study the distinct and effective resource acquisition strategies that were developed by hominins during this period. The archaeological site of Notarchirico (695–610 ka) is a key locality for the study of the behavior of hominin groups in the Italian Peninsula and Western Europe. The site is one of the few open-air sites to have yielded human remains, namely a femur fragment of Homo heidelbergensis, in such ancient chronologies. Notarchirico also yielded numerous lithic and faunal remains, although the latter, despite their abundance, have so far received scarce attention from a taphonomic perspective. Here we present a study of the site, including material from both ancient and modern collections. Spatial and taphonomic inferences can be drawn about the formation of the assemblages, as well as behavioral inferences about the Middle Pleistocene hominin populations. Despite the poor preservation of the bones, the data suggest that both hominins and carnivores foraged in the area. From a taphonomic perspective, spatial analyses suggest that water flows may have altered the association between osteological and lithic assemblages. There is compelling evidence that suggests that hominin groups inhabited the area surrounding the site for a minimum of 100 ka as the region was abundant in resources. Notarchirico is a pivotal site for understanding the adaptation of hominins and their interaction with the Middle Pleistocene ecosystems
Overview of LifeCLEF 2025: Challenges on Species Presence Prediction and Identification, and Individual Animal Identification
No full textInternational audienceBiodiversity monitoring using AI-powered tools has become vital for tracking species distributions and assessing ecosystem health on a large scale. Automated image- and sound-based species recognition, in particular, continues to accelerate conservation efforts by enabling rapid, low-cost surveys of vulnerable populations. However, the ever-growing variety of algorithms and data sources underscores the need for standardized benchmarks to assess real-world performance. Since 2011, the LifeCLEF lab has filled this role by organizing annual evaluations that promote collaboration among AI experts, citizen science, and ecologists. In this overview, we report on the LifeCLEF 2025 edition, which featured five distinct, data-driven tasks: (i) AnimalCLEF, focusing on open-set individual animal re-identification; (ii) BirdCLEF+, about species recognition in complex acoustic soundscape recordings; (iii) FungiCLEF, addressing few-shot classification of rare fungi species; (iv) GeoLifeCLEF, combining environmental and high-resolution remote sensing with occurrence records to predict plant species presence; and (v) PlantCLEF, aiming to identify multiple co-occurring plant species in vegetation-plot imagery. This paper provides an overview of the motivation, methodology, and main outcomes of the five challenges
Dynamic programming on bipartite tree decompositions
No full textInternational audienceWe revisit a graph width parameter that we dub bipartite treewidth (btw). Bipartite treewidth can be seen as a common generalization of treewidth and the odd cycle transversal number, and is closely related to odd-minors. Intuitively, a bipartite tree decomposition is a tree decomposition whose bags induce almost bipartite graphs and whose adhesions contain at most one “bipartite” vertex, while the width of such decomposition measures the number of “non-bipartite” vertices in a bag. We provide para-NP-completeness results and develop dynamic programming techniques to solve problems on graphs of small btw. In particular, we show that -Subgraph-Cover, Weighted Independent Set, Odd Cycle Transversal, and Maximum Weighted Cut are parameterized by btw. We also provide the following dichotomy when H is a 2-connected graph: if H is bipartite, then H-{Subgraph/Induced-Subgraph/Odd-Minor/Scattered}-Packing is para-NP-complete parameterized by btw while, if H is non-bipartite, then the problem is solvable in XP-time
Insight into cooling requirements for thermophotovoltaic devices
No full textInternational audiencePerformance of thermophotovoltaic conversion devices depends on the operating temperature of the cell, and thus on how heat generated in the cell is dissipated. The present research examines the cooling requirements that allow the cell to operate at a specified temperature, based on the parameters influencing electrical power generation. A detailed balance approach and a simple thermal model involving an effective heat transfer coefficient are used. Key parameters, such as emitter temperature, view factor, in-band transmission and out-of-band transmission functions, and external radiative efficiency, are systematically varied to evaluate their influence on pairwise efficiency and power density, and on the required effective heat transfer coefficient to ensure that the cell operates at selected temperatures. Although thermophotovoltaic cells are typically presumed to function at close to ambient, our findings indicate that maintaining this operating temperature necessitates a cooling system with a substantially high effective heat transfer coefficient (∼ 10^3 -10^4 Wm -2 K -1 ). The cooling challenge grows when the cell bandgap diminishes, due to the interplay of rising power density and decreasing pairwise efficiency. The cooling requirements increase with the temperature of the emitter and the view factor. Nevertheless, they can be mitigated by reducing both in-band and out-of-band transmission functions. They are underestimated, and the bandgap optimizing pairwise efficiency or power density is inadequately predicted when the cell is assumed to operate in the radiative limit. These insights into cooling requirements imply that they should be considered from the initial stages of thermophotovoltaic device design
A close-up at the paleoecology of the most western gelada relatives: Insights from dental microwear texture analysis
No full textInternational audienceExploring the paleoecology of extinct species of the genus Theropithecus, which was widespread and diversified in Africa during the Pliocene and the Pleistocene, is crucial to have a full picture of the evolutionary history of this taxon. It also gives insights into the fundamental ecological range of the genus, now restricted to the Ethiopian highlands in a reduced set of habitats. This study aims to investigate the diet of Theropithecus atlanticus (n = 8) from the Plio-Pleistocene site of Ahl al Oughlam (Morocco) through dental microwear texture analysis. We used a recently developed software, 'trident', that quantifies the heterogeneity of texture parameters through subsampled wear surfaces to improve dietary discriminations. We considered a comparative dataset of extant primates (n = 104) with different diets, including the leaf-eater Colobus guereza, the grass-eater Theropithecus gelada, and the generalists Papio hamadryas and Chlorocebus aethiops. In addition, we compared with specimens of theropiths (n = 80) from the eastern African Shungura Formation (Lower Omo Valley, Ethiopia) that are nearly contemporaneous to T. atlanticus. Our results indicate that T. atlanticus was mostly feeding on grasses, as its extant relative. Some similarities with opportunistic species suggest it might have consumed a substantial amount of challenging foods. This dental microwear texture is in line with open, arid and harsh environments, and the presence and abundance of C3 grasses at Ahl al Oughlam detected by enamel stable isotopes analysis on various mammals including theropiths. This contrasts with the environment described on nearly contemporaneous specimens from the Lower Omo Valley where grasses were abundant but composed of C4 ones
Impact of wheat-legume mix intercrops on wheat epidemics by modelling
No full textInternational audienceHighlights: • Simulated intercropping decrease disease intensity and improve protectiveness while canopy indicators predict such effects. • Pea intercropped with wheat decreased disease intensity compared with faba bean. • Nitrogen fertilization increased disease intensity. • This study stressed the critical lack of experimental data on disease in intercropping.Abstract: Context : Intercropping is a promising strategy for integrated disease management and agroecological transition, although experimental and modelling studies are scarce.Objectives: This study aims to understand and quantify the impact of non-host species choice and nitrogen (N) fertilization on disease epidemics in the context of intercropping.Methods: We collected existing experimental data on LAI based on a literature survey of non-diseased wheat intercropped with different non-host legume species (pea and faba bean) and N fertilization treatments. Based on a foliar epidemic model for intercropping, we simulated epidemics directly on these experimental data of LAI. The model is parameterized for two wheat fungal diseases: Septoria tritici blotch, a rain-borne disease, and wheat leaf rust, an air-borne disease.Results: Our results indicate that intercropping can decrease disease intensity and improve protectiveness for both diseases. Effect depends however on species choice as pea intercropped with wheat leads to lower disease intensity and better intercropping protectiveness compared with faba bean, whereas N fertilization increased disease intensity. We also found that crop indicators describing wheat leaf area index (LAI) can predict disease intensity, whereas indicators describing companion LAI can better predict intercropping protectiveness.Conclusions: Intercropping can significantly reduce fungal epidemics on wheat, and intercropping management practices can be optimized for effective disease management in wheat-legume intercrops. The dilution effect is more related to disease intensity, while the barrier effect is more related to intercropping protectiveness.Implications: These findings pave the way for identifying field indicators to predict epidemics. However, this study also stressed the critical lack of experimental data on disease in intercropping
Un partage d’expérience autour de la pratique de l’interdisciplinarité sur les feux : le projet EcoSoFI (2022-2024)
No full textInternational audienceLes collaborations inter/transdisciplinaires autour de la compréhension des feux et de leur gestion sont plébiscitées, mais leur mise en œuvre ne va pas pour autant de soi. A partir du partage d’expériences de plusieurs scientifiques et gestionnaires, le présent article restitue la démarche que nous avons adoptée pour comprendre ces difficultés ; et tire quelques constats et propositions. Onconstate notamment la dominance des sciences biophysiques et le poids de la modélisation dans les interfaces entre recherche et gestion. Au sein des SHS, on observe également des partitions entre disciplines et sous-disciplines, ainsi qu’une « interdisciplinarité inachevée » dans l’analyse des changements de régimes de feux. La spécialisation disciplinaire a conduit à une autonomisation du questionnement et des méthodes, qui ne sont plus explicitées ni interrogées au regard des autres approches et du terrain. Nos propositions consistent à remettre en question les catégories implicites concernant les pratiques et les savoirs liés aux feux et à définir des protocoles de recherche permettant des problématisations communes à partir d’études de cas localisées et « concrètes »
Efficient Edge AI Learning with Equilibrium Propagation: A Practical Solution For Gradient Computation
No full textInternational audienceThe rapid growth of smart devices and sensors has led to an overwhelming increase in data generation, pushing current network infrastructure to its limits and threatening the scalability of cloud-based processing. Edge machine learning, which processes data locally on devices, presents a viable solution to reduce network load and latency. However, deploying deep learning at the edge remains difficult due to the limited memory and computational capacity of these devices which mostly precludes on-device/on-site training. Equilibrium propagation (EP) has emerged as a promising alternative to backpropagation, leveraging analog processing and device physics for energyefficient learning. Yet, its practical implementation is hindered by challenges such as voltage variations and the need for energyefficient circuits capable of gradient computation at a sufficient level of accuracy. Existing solutions rely on impractical idealized models. In this work, we introduce a novel method to address the problem of the wide dynamic range of the voltage variation to avoid the use of expensive low-noise amplifiers, and propose an innovative transistor-level switched-capacitor circuit to compute gradients in accordance with the EP rule. Additionally, our design supports batching, a key requirement for stable training that is often overlooked. We validate our approach on the MNIST dataset, demonstrating a practical, energy-efficient EP circuit that operates within real hardware constraints
Vertex identification to a forest
No full textInternational audienceLet H be a graph class and k ∈ N. We say a graph G admits a k-identification to H if there is a partition P of some set X ⊆ V (G) of size at most k such that after identifying each part in P to a single vertex, the resulting graph belongs to H. The graph parameter id H is defined so that id H (G) is the minimum k such that G admits a k-identification to H, and the problem of Identification to H asks, given a graph G and k ∈ N, whether id H (G) ≤ k. If we set H to be the class F of acyclic graphs, we generate the problem Identification to Forest, which we show to be NP-complete. We prove that, when parameterized by the size k of the identification set, it admits a kernel of size 2k + 1. For our kernel we reveal a close relation of Identification to Forest with the Vertex Cover problem. We also study the combinatorics of the yes-instances of Identification to H, i.e., the class H (k) := {G | id H (G) ≤ k}, which we show to be minor-closed for every k when H is minor-closed. We prove that the minor-obstructions of F (k) are of size at most 2k + 4. We also prove that every graph G such that id F (G) is sufficiently big contains as a minor either a cycle on k vertices, or k disjoint triangles, or the k-marguerite graph, that is the graph obtained by k disjoint triangles by identifying one vertex of each of them into the same vertex
Efficient Control Allocation and 3D Trajectory Tracking of a Highly Manoeuvrable Underactuated Bio-inspired AUV
No full textInternational audienceFin actuators can be used for both thrust generation and vectoring. Therefore, fin-driven autonomous underwater vehicles (AUVs) can achieve high maneuverability with a smaller number of actuators, but their control is challenging. This study proposes an analytic control allocation method for underactuated AUVs. By integrating an adaptive hybrid feedback controller, we enable an AUV with 4 actuators to move in 6 degrees of freedom (DOF) in simulation and up to 5 DOFs in real-world experiments. The proposed method outperformed state-of-the-art control allocation techniques in 6-DOF trajectory tracking simulations, exhibiting centimeter-scale accuracy along with energy and computational efficiency. Real-world pool experiments confirmed the method's robustness and efficacy in tracking complex 3D trajectories, with significant computational efficiency gains (0.007 ms vs. 22.28 ms). Our method offers a balance between performance, energy efficiency, and computational efficiency, showcasing a potential avenue for more effective tracking across multiple DOF for underactuated underwater robots