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Data from long-term experiments in temperate croplands to evaluate soil organic carbon models
No full textInternational audienceSoil organic carbon (SOC) models need independent evaluation against field measurements, but those latter are rarely publicly available and harmonized. In this study, we collected and shared data from 167 agronomic treatments in 34 agronomic long-term experiments (LTEs) located in temperate croplands, allowing the evaluation of several soil organic C models such as RothC, Century, AMG, MIMICS, ICBM, Millenial, and CTOOL. The dataset includes climate data, soil properties, C inputs from crops (n = 4588 records) and organic amendments, irrigation data, monthly soil cover, as well as SOC stock measurements in the topsoil layer (n = 1328 records). Climate, soil moisture, and soil temperature data were extracted from daily climate databases. Carbon inputs from crops were calculated from observed yields and harvest index, with some harvest index values estimated, combined with crop allometric coefficients from the literature. Descriptions of LTE, agronomic treatments, methodological metadata, and a part of the code, accompanies the dataset. The dataset can be reused to evaluate single SOC models, or to evaluate an ensemble of models
Drastic changes in tidal hydrodynamics following seagrass decline and their seasonal variations in a shallow lagoon
No full textInternational audienceOver the past decades, seagrasses have drastically declined worldwide, reducing their capacity to regulate flow conditions. Intertidal species have been particularly affected by this decline, yet there is limited understanding of how intertidal seagrass loss influences hydrodynamics in shallow coastal lagoons. In this study, we use a 3D flow-vegetation model that accounts for vegetation effect on mean and turbulent flow, as well as flow-induced leaf bending, to investigate how tidal hydrodynamics respond to seasonal and multi-decadal changes in intertidal seagrass characteristics. The model is applied to the Arcachon lagoon (France), colonized by extensive Zostera noltei and Zostera marina meadows. This study reveals that a short-leaf and flexible seagrass species such as Zostera noltei can regulate tidal hydrodynamics throughout the lagoon due to the presence of broad and dense meadows on the tidal flats. In summer, seagrass decline leads to a significant increase in the 75th percentile in bottom flow velocities (+100 %) on the tidal flats, but to a decrease in the channels (−20 %). However, in winter, the response of tidal hydrodynamics to the reduction in seagrass coverage is far less pronounced. Comparison of simulated scenarios reveals that the multi-decadal decline of Zostera meadows with summer characteristics and the seasonal loss between summer and winter lead to modifications in tidal-flow parameters (current velocities, tidal asymmetry, high-tide water level) of a comparable magnitude. These changes in hydrodynamics likely enhance suspended sediment concentration, reducing light availability, contributing to further seagrass loss, and modifying sediment management for stakeholders due to enhanced siltation in channels.
Fault Kinematics of the 2019–2026 Puerto Rico Earthquake Sequence: Conjugate Faulting Within a Zone of Oblique Subduction
No full textInternational audienceThe 2019-2026 southwestern Puerto Rico earthquake sequence has the characteristics of an earthquake swarm with over 9,000 events of Mw 2.5 or greater over an area of 1,500 km 2 , and the largest event is an Mw 6.4 on 7 January 2020. Previous studies have proposed two structural interpretations: (a) an E-striking, N-dipping normal fault hosting the largest event with a left-lateral oblique slip; superimposed on this fault is an X-shaped conjugate strike-slip faults reflecting NE-SW shortening; and (b) a NE-striking, SE-dipping normal fault of the largest event with a right-lateral oblique slip. Based on focal mechanism solutions, global navigation satellite system (GNSS) and satellite radar interferometry data, we propose four fault families that define a slightly different X-shaped pattern: (a) left-lateral WNW-ESE faults including two parallel faults that define a 12-km-wide stepover area and pull-apart basin; (b) an WSW-ENE left-lateral fault; (c) right-lateral NNE-SSW faults; and (d) E-W left-lateral oblique-slip normal faults including the one hosting the largest event inside the pull-apart basin. This active fault kinematics closely reflects measured faults in Late-Miocene-Pliocene rocks, indicating that this deformation pattern has been active for several million years. The proposed fault kinematic model is consistent with geodetic data and an overall crustal deformation model of coupled NW-SE extension and NE-SW compression produced by oblique convergence across the North America-Caribbean plate boundary. The occurrence of prolonged earthquake sequence on crustal conjugate systems poses a seismic hazard for this oblique plate boundary.Plain language Summary:The 2019-2026 (still continuing in February 2026) Puerto Rico earthquake sequence has characteristics of an earthquake swarm, with the largest event being an M6.4 on 7 January 2020. Seismic data indicate that the M6.4 can occur on two possible fault planes with different slip directions: either left-lateral on a N-dipping fault or right-lateral on a SE-dipping fault. Using global navigation satellite system and satellite synthetic aperture radar displacement measurements, we compared the inversed displacements of the two fault models found that the N-dipping model fits the observations better. We then interpret the slip directions of earthquakes and delineate four fault families: (a) WNW-ESE left-lateral strikeslip faults including two parallel ones, (b) an WSW-ENE left-lateral fault, (c) NNE-SSW right-lateral strike-slip faults, and (d) E-W left-lateral normal faults with oblique slip. Two parallel WNW-ESE faults define an extensional basin, this fault pattern explains the N-S direction difference among the GNSS stations and the swarm-like characteristics of the sequence. These earthquakes reflect continued crestal extension (i.e., extension related to the top of an anticlinal axis) along the Puerto Rico-Virgin Island basement arch. Similar earthquake sequences are not controlled by regional faults and can occur over the North America-Caribbean plate boundary
A multi-methods analysis to assess the challenges of pineapple cultivation in Moorea and the capability of taro to mitigate impacts on human and environmental health
No full textAbstract Resulting from a collaboration between the CRIOBE (Centre de Recherches Insulaires et Observatoire de l’Environnement), and ChimEco, this article examines the cultural and ecological importance of taro cultivation in the context of a socio-ecological transition on Moorea since the 1950s. The methods used are based on individual, non-directive, participatory surveys in Moorea and the urban area of Faaa (Tahiti) among government agencies, the private and public sectors, the general public, and civil society. These surveys and analyses highlight the controversial nature and sources of tension related to the socio-ecological transition on Moorea. They highlight the lack of negotiation and inclusiveness in the management of the "land-sea continuum" and the contemporary role attributed to taro as a possible solution to the challenges of the transition. Finally, this article discusses the characteristics of the "land-sea continuum" from a Polynesian perspective, with a view to management by the socio-ecosystem, from the mountain to the reef
Le « pouvoir d’achat » depuis une cour burkinabè : quelles résonances des prix et des revenus dans les sentiments d’injustice ?
No full textInternational audienceAlthough purchasing power is now a common concern for working-class people around the world, its moral and political understanding varies depending on time and place. This article questions the resonance of repectively prices and incomes on feelings of injustice related to purchasing power, in a society that has never been wage-earning. It draws on research conducted in a working-class neighbourhood of Ouagadougou, Burkina Faso, from the perspective of a family courtyard. The issues considered include daily consumption and work, as well as the everyday understanding of economic concepts, and the socially and historically specific ways in which normative expectations regarding the authorities are formed.Le « pouvoir d'achat » semble constituer une préoccupation partagée par de nombreuses populations à travers le monde, au point que l'on pourrait oublier que cette notion, ou ses diverses traductions, n'a pas forcément les mêmes résonances ici et là, pas plus qu'elle n'a toujours eu la même signification 1 . Aujourd'hui, elle entretient un lien étroit avec le mécontentement social en étant souvent invoquée par (ou au nom) des populations sans pouvoir, dans les périodes où leurs conditions de vie se dégradent. Mais son articulation avec la demande de justice peut se décliner bien différemment selon le lieu et le moment. S'il est attendu qu'une baisse du pouvoir d'achat s'accompagne de difficultés matérielles, il n'est pas évident que ces difficultés suscitent des sentiments d'injustice face à l'autorité politique. Et quand bien même ce serait le cas, il n'est pas non plus certain que ces sentiments s'adossent aux prix, aux revenus ou aux deux à la fois : la sensibilité à ces deux variables ne sera pas forcément la même selon le lieu, le moment, ou encore selon la personne dans un même espace et au même moment. Aussi est-il important de dénaturaliser ce concept de pouvoir d'achat qui, outre les multiples critiques qu'on peut lui adresser, invisibilise la charge morale respective de ses deux composants, les prix et les revenus, telle qu'elle est ressentie par les premiers intéressés. C'est ce à quoi je voudrais m'employer dans cet article, en me plaçant d'un point de vue micro-situé : la cour d'un quartier populaire de Ouagadougou au Burkina Faso.1. Au xix e siècle, l'expression « pouvoir d'achat » était principalement employée par les économistes européens pour désigner la valeur relative des monnaies en fonction des marchandises qu'elles permettaient d'acquérir : ce n'est qu'à partir de la Grande dépression des années 1930 qu'elle fut plus largement associée aux conditions de vie des classes laborieuses (Dreyfus 1935). Le "pouvoir d'achat" depuis une cour burkinabèQuelles résonances des prix et des revenus dans les sentiments d'injustice ?</div
L’estetica di Hegel attraverso i quaderni degli studenti: nuove traduzioni, sfide e prospettive
No full textInternational audienceAu cours des dernières décennies, à la suite du «tournant philologique» des années 1990, l’étude de l’esthétique hégélienne a été profondément renouvelée grâce à la redécouverte des cahiers de notes rédigés par les auditeurs et les étudiants qui ont suivi les cours de Hegel à l’université de Berlin entre 1820 et 1829. Longtemps négligés, ces documents ont redonné une image plus vivante et élaborée de la pensée de Hegel sur l’art, ouvrant de nouvelles perspectives d’interprétation. Cet ouvrage propose une reconstruction claire et actualisée des principales lignes de recherche issues de ce travail de redécouverte, de transcription, d’édition et de traduction des sources manuscrites. Les différents essais réunis dans ce volume montrent que l’enseignement universitaire a été un moment décisif de la réflexion hégélienne, au cours duquel la philosophie de l’art a été définie comme une partie essentielle du système et comme un lieu de réflexion sur la relation entre la forme artistique, l’esprit et l’histoire. Le présent volume invite ainsi à relire l’esthétique de Hegel non pas comme un corpus statique, mais comme une pensée en mouvement, profondément liée à la pratique même de l’enseignement et à son contexte historique.Negli ultimi decenni, a seguito della “svolta filologica” degli anni Novanta, lo studio dell’estetica hegeliana è stato profondamente rinnovato grazie alla riscoperta dei quaderni di appunti redatti dagli uditori e dagli studenti che frequentarono i corsi tenuti da G.W.F. Hegel all’Università di Berlino tra il 1820 e il 1829. Questi materiali, a lungo trascurati, hanno restituito un’immagine più viva e articolata del pensiero di Hegel sull’arte, aprendo nuove prospettive interpretative. Il volume si propone di offrire una ricostruzione chiara e aggiornata delle principali linee di ricerca emerse a partire da questo lavoro di scoperta, trascrizione, edizione e traduzione delle fonti manoscritte. I diversi saggi ospitati in questo volume mostrano come l’insegnamento universitario rappresenti un momento decisivo della riflessione hegeliana, in cui la filosofia dell’arte si definisce come parte essenziale del sistema e come luogo di interrogazione del rapporto tra forma artistica, spirito e storia. Il volume invita così a rileggere l’estetica di Hegel non come un corpus statico, ma come un pensiero in movimento, profondamente legato alla pratica della lezione e al suo contesto storico
Reference-Free Sampling-Based Model Predictive Control
No full textInternational audienceWe present a sampling-based model predictive control (MPC) framework that enables emergent locomotion without relying on handcrafted gait patterns or predefined contact sequences. Our method discovers diverse motion patterns, ranging from trotting to galloping, robust standing policies, jumping, and handstand balancing, purely through the optimization of high-level objectives. Building on model predictive path integral (MPPI), we propose a cubic Hermite spline parameterization that operates on position and velocity control points. Our approach enables contact-making and contact-breaking strategies that adapt automatically to task requirements, requiring only a limited number of sampled trajectories. This sample efficiency enables real-time control on standard CPU hardware, eliminating the GPU acceleration typically required by other state-of-the-art MPPI methods.We validate our approach on the Go2 quadrupedal robot, demonstrating a range of emergent gaits and basic jumping capabilities. In simulation, we further showcase more complex behaviors, such as backflips, dynamic handstand balancing and locomotion on a Humanoid, all without requiring reference tracking or offline pre-training
Study of the impact of a mixture of minerals on the apparent zeta potential of porous media
No full textInternational audienceThe zeta potential is a key interfacial property for understanding boundary conditions at solid–fluid interfaces and at the fluid–fluid interfaces. It plays a critical role in a wide range of engineering processes and theoretical studies. In natural geological materials, however, the zeta potential cannot be measured directly and must be inferred from macroscopic electrokinetic observations. Because most porous media contain mixtures of minerals with distinct interfacial properties, self-potential measurements reflect an apparent zeta potential rather than a single intrinsic value. Existing capillary-bundle formulations typically assume a spatially uniform surface charge, an assumption that breaks down in heterogeneous composite materials.Here we develop an analytical framework that quantifies how mineralogical heterogeneity controls the apparent zeta potential of porous mixtures. By extending the bundle-of-capillaries model, we derive Voigt- and Reuss-type mixture laws that represent two end-member configurations: parallel and series arrangements of surface-charge heterogeneities. The theoretical predictions are evaluated using pore-network simulations and published experimental data. When mineral phases share similar pore-size distributions, the apparent zeta potential follows a Voigt-type mixing rule. Incorporating empirical Zeta–pH relationships for silica and calcite reproduces the observed pH dependence and polarity reversal of the apparent zeta potential as mineral proportions vary.The proposed framework provides a physically consistent link between mineral composition, surface-charge variability, and electrokinetic responses, improving the interpretation of self-potential signals in heterogeneous natural porous media
Paying attention to other animal detections improves camera trap classification models
No full textData and code are available via https://doi.org/10.5281/zenodo.15736089 (Dussert et al., 2026)International audience1. In ecological studies, automated species classification models are increasingly used to process large volumes of camera trap images. Most current classification models rely on a two-step pipeline: a detector first locates and crops animals, followed by a classifier that predicts species independently for each crop. While effective, these models still struggle under challenging conditions and ignore temporal context or information from nearby animals available in sequences of camera trap images, whereas human annotators often use it in difficult cases.2. We propose to leverage self-attention, a core mechanism of Large Language Models and Vision Transformers, to enable the model to learn relationships between crops occurring in similar contexts. Our self-attention module operates directly on the set of crop embeddings, producing new representations enriched with information from other crops, improving species classification. The module fits into the two-step pipeline without requiring structural change and adds only minimal computational overhead. To address the lack of annotated multi-species sequences, we develop a training strategy that synthetically generates multispecies sequences from mono-specific ones.3. Compared with an independent classifier baseline, our multi-crop model achieves higher accuracy on mono-specific sequences, both real and synthetic. In multispecies settings, evaluated using synthetic test sets, we also observe a substantial improvement in accuracy. Using real but weakly annotated multi-species sequences, we reformulate the task as multi-label set classification and conduct a visual analysis to highlight the benefits of our approach.4. By leveraging the information brought by all detections of animals in the image and others of the same sequence, our approach reduces species misclassifications and enables more accurate estimates for downstream ecological analyses focusing on, for instance, species richness, occupancy and species interaction