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Reconstructing the freshwater paleoecosystems diversity of Toros-Menalla (Late Miocene, Chad) from an integrated faunal perspective
No full textAquatic environments are critical components of past ecosystems that shaped species distribution and survival. Yet in hominin-bearing fossil sites, they are often treated as uniform or poorly detailed elements of “mosaic” landscapes, failing to capture their ecological complexity. In the northern Chad Basin, the late Miocene Toros-Menalla area records vast perilacustrine systems where aquatic and terrestrial ecosystems were deeply interconnected. While terrestrial vertebrate assemblages have been well characterised as reflecting a heterogeneous landscape, the aquatic component remains poorly resolved. Variations in depositional settings, aquatic vertebrate diversity, stable isotope data, and field observations point to a more complex and dynamic network of freshwater habitats. An integrative study of aquatic and semi-aquatic vertebrate assemblages from five Toros-Menalla sites reveals distinct faunal structures reflecting different ecological preferences and depositional conditions, ranging from perilacustrine floodplains to swampy, vegetated, or marginal waters and large open waterbodies with current. These environments, distributed across several hundreds of meters up to 30 km, represent lateral habitat diversity rather than temporal succession, as most assemblages formed geologically instantaneously (except for TM266, where vertical mixing could be hypothesised). Comparison with the present-day Bol Archipelago on the northeastern shores of Lake Chad provides a suitable analogue for the Toros-Menalla paleoenvironment. There, interdunal water bodies of varying depth and connectivity create a dynamic network of aquatic habitats at a similar spatial scale. This study underscores the need for systematic, grid-based collection and sieving of fossils to capture representative aquatic biodiversity and structure, and to reconstruct freshwater paleoenvironments with greater ecological precision
EEG theta dynamics for error processing during online movement control
No full textInternational audienceTo ensure optimal visuomotor feedback control during manual tracking, the brain must continuously monitor the error between the hand and the target. Modulations in the theta band (3-8 Hz) are related to error processing, but this has been mainly shown in cognitive control contexts. Hence, their relationship with hand-target errors during online control remains unclear. Here we assessed the impact of motor error processing on EEG theta-band activity in 29 healthy participants while they performed continuous tracking of a moving target with their dominant (right) hand. Two conditions were used to manipulate error processing demands: 1) in the Repeated condition, the same target trajectory was presented 80 times, allowing participants to implicitly learn the pattern and reduce tracking errors; 2) in the Random condition, 80 different trajectories were used, inducing persistent high tracking errors. Behavioral analyses confirmed that tracking errors were significantly higher in the Random than in the Repeated condition. Importantly, EEG theta power was also significantly higher in the Random condition, with a peak difference occurring at electrodes overlaying the left sensorimotor regions. This effect was selective to theta activity, as there was no modulation in alpha-(8-12 Hz) and beta-band (15-30 Hz) activity. Overall, this study extends the role of theta oscillations to online error processing in the context of motor control. It is possible that theta modulations reflected cortical activity mediating the communication and integration of information within sensorimotor circuits including the motor, premotor and parietal cortex, which are known to mediate online movement control. Highlights • Theta power increased with tracking error demands over contralateral sensorimotor regions• No differences in parieto-occipital alpha or sensorimotor beta across conditions• Suggests parieto-frontal sensorimotor integration for online motor error correction</div
Combating resilient Acanthamoeba castellanii cysts: Ultrasonic frequency-dependent effects on viability and excystment
No full textInternational audienceFree-living amoebae (FLA) are significant environmental reservoirs for numerous pathogenic microorganisms. These protists exhibit remarkable resilience, often evading biocides due to their ability to form highly resistant dormant cysts under unfavorable conditions. This study investigated the effects of ultrasound treatment on the viability of these amoeba cysts, using Acanthamoeba castellanii, a prevalent water and soil amoeba, as a model. We found that low-frequency ultrasound treatment significantly impaired the revival of Acanthamoeba cysts. In contrast, high-frequency ultrasound effectively ruptured cyst walls and induced direct amoebal death. Further investigation using tert-Butanol, an OH radical scavenger, partially mitigated the effects induced by highfrequency ultrasound, demonstrating that reactive oxygen species contribute to amoeba damages. Our results highlight ultrasound's significant potential as an efficient and effective strategy to combat resilient Acanthamoeba cysts
Primary School Teachers’ Media and Information Literacy: A Contrastive Study Between France and Peru
No full textInternational audienceThis qualitative study examines the implementation of Media and Information Literacy (MIL) in French and Peruvian primary schools, considering teachers’ information practices. Data collection involved individual teacher interviews (21), classroom observations (20), and student group interviews (21) in both countries. Despite contrasting national contexts, findings reveal a scarcity of MIL-focused learning activities, with information-seeking tasks being the most prevalent, often occurring outside of school hours (such as homework). While teachers acknowledge the importance of MIL, time constraints, technical and pedagogical challenges, and a lack of dedicated training were cited as significant barriers. Teachers rely heavily on self-training and personal information habits to implement MIL-related learning activities in the classroom. They struggle with information seeking for teaching purposes, such as lesson plans. Theoretically, the study highlights the need to address the research gap on teachers’ information practices. Practically, the findings shed light on the necessity of educating primary school teachers in the MIL area, taking into account the role of information in their everyday lives as well as in their jobs, and the way these information experiences shape classroom MIL implementation. Findings suggest that public policies should consider teachers’ actual ability to educate students in MIL (beyond computer equipment and how-to-use training) to reduce information inequalities
“A monument more lasting than bronze”: Fragile inscriptions in the garden
No full textInternational audienceThis chapter builds on the analogy between the garden and the book as spaces of graphic practice, in order to explore the elision between page, garden, and land. It focuses on three inscriptions that thematize the ambivalence of the garden as a site of permanence and change. The first one is an inscribed headstone in Little Sparta, the garden of the Scottish poet Ian Hamilton Finlay. The second one is a vignette that was wood engraved by Agnes Miller Parker for Herbert Furst’s Essays in Russet (1946), and the third one is a tailpiece depicting an inscribed rock in Thomas Bewick’s A History of British Birds (1804). Because they are linked by a common thread of references, this chapter proposes to examine how these carved texts and printed artefacts exemplify anxieties about cultural transmission. More largely, it explores how the intermedial crossovers between text and image, carving and organic growth speak of the relationship between the human and the non-human worlds
Confinement properties of zeolite-rich rocks with respect to water and various ionic tracers
No full textInternational audienceThe studied materials are zeolite-rich rocks (>70 wt% analcime, named analcimolite) forming a laterally continuous aquitard within the southern of the Tim Mersoï Basin (Niger). This unit, commonly referred to as the Abinky Formation, occurs as three mineralogical facies: a reduced facies containing Fe-chlorite, an oxidized facies with hematite, and an intermediate 'transition' facies. This analcimolite unit acts as an aquitard, separating the overlying and underlying sandstone aquifers, the latter locally providing potable water. Due to the low permeability of these analcime-rich rocks, diffusion is expected to be the dominant transport mechanism. However, no data on transport properties in zeolite-rich formations have been reported, and the mobility of water and ionic solutes remains unknown. This study aims to characterize diffusion in the three facies of the Abinky formation, identifying key controls on water and ion transport prior to any anthropogenic perturbation. Through-diffusion experiments using water tracers (HDO and HTO) showed that water diffusion (effective diffusion coefficient from 1.3 to 2 × 10 -11 m²/s) is primarily controlled by pore throat size rather than total porosity. A dual-porosity model was required, distinguishing a fast-transport network (open, low-tortuous zones) from a slow one (confined, tortuous zones). Despite variations in diffusion coefficients, all data are interpreted with capacity factors equal to total external porosity measured by water impregnation (excluding crystal water located in zeolite micropores). This confirms that water behaves as an inert tracer and that micropores contribute negligibly to water migration. For ionic tracers in reduced facies, 36 Cl -is partially excluded from external pores (anionic exclusion) and slightly adsorbed, with an extent of about 0.1 meq/100 g, a very small value compared to the cation exchange capacities of such rocks (up to ~40 meq/100 g for H+ and NH4+ ). In contrast, ²²Na⁺ exhibits strong adsorption due to isotopic exchange with 23Na+ in the analcime framework, leading to a diffusivity ~4 times higher than that of water. This dataset is a first step in constraining reactive transport models of water and solutes in zeolite-rich porous media under environmental conditions and prior to anthropogenic disturbance
Les formations agricoles dans le monde à l’épreuve de l’agroécologie
No full text[Articles publiés progressivement par la revue] Dans le cadre de l'approche des comparaisons internationales, ce dossier spécial de la revue Cahiers Agricultures vise à analyser les évolutions des curriculums des formations agricoles à travers le monde, tant dans les pays du Nord que du Sud, dans le contexte de montée en puissance des politiques de « transition agroécologique ». Il s'agit de comprendre les enjeux de l’élaboration des programmes des formations en agroécologie en fonction des définitions de l’agroécologie selon les contextes nationaux ou locaux, leur adoption et appropriation par les personnels de formation et leur réception par les publics concernés. Face à la prise de conscience croissante des enjeux environnementaux liés à l’agriculture, les politiques publiques réorientent les formations agricoles vers l’adaptation aux changements climatiques, la réduction d’usages des pesticides à travers l’intégration de nouveaux savoirs agronomiques en cours d’élaboration. Le premier axe propose d’interroger la manière dont les programmes d’enseignement (ou référentiels de formation) sont conçus pour répondre aux enjeux de la « transition agroécologique » (Métral, et all, 2016). Il s’agit d’analyser la traduction curriculaire des différentes conceptions de l’agroécologie. En effet, les définitions multiples de l’agroécologie (scientifique, politique, sociale, etc.), sa traduction en principes (HLPE 2019, FAO 2020, Wezel et al. 2020) se reflètent dans les contenus de formation, ce qui peut être source de tensions ou permettre au contraire d’intégrer une diversité de points de vue, de référentiels. Il s’agit aussi d’interroger les mécanismes qui permettent de sourcer plus rapidement les enseignements agronomiques sur les conditions d’activation d’innovations agroécologiques que documentent différents acteurs (recherche agronomique, organisations professionnelles, société civile). Le deuxième axe invite à examiner la manière dont les personnels de formation — enseignants, formateurs, conseillers, maîtres de stage — s’approprient et traduisent dans leurs pratiques pédagogiques ou professionnelles les référentiels et les orientations curriculaires liés à l’agroécologie (Gaborieau, Peltier, 2024). L’enjeu est de comprendre comment ces acteurs, situés à l’interface entre prescriptions institutionnelles et réalités locales, participent à la mise en œuvre effective des transformations attendues. Le troisième axe s’intéresse à la manière dont les publics en formation — élèves, étudiants, agriculteurs en reconversion, adultes en formation continue — reçoivent, interprètent et s’approprient (ou non) les savoirs agroécologiques transmis. L’objectif est d’analyser comment ces nouveaux contenus, porteurs de transformations profondes des pratiques agricoles, résonnent avec les trajectoires sociales (Sahuc, 2017), les représentations professionnelles et les projets de vie des apprenants
Motor complications and postural abnormalities interplay in Parkinson's disease
No full textInternational audienceBackground: Postural abnormalities (PA) and motor complications (MCs, including motor fluctuations - MFs- and levodopa-induced dyskinesia - LIDs) are hallmark of Parkinson's disease (PD) progression, yet their relationship remains poorly understood.Objective: To investigate the association between PA and MCs, motor symptoms, and non-motor symptoms (NMS) in patients with PD, and to assess whether PA influences the development of MCs over time.Methods: Data of the prospective NS-Park cohort (27 French PD Expert Centers) were analysed. PA was defined by a score ≥2 on item 3.13 of the MDS-UPDRS-III. Associations between PA and MCs, as well as with other motor symptoms and NMS, were assessed using logistic regression models. We used interval censoring survival models to assess the associations between PA at inclusion and the incidence of MCs. Analyses were adjusted for sex, age, disease duration, dopaminergic dose, and disease severity.Results: Among 13,037 included PD patients (58.7 % male, median age at diagnosis 61 years), 724 (5.6 %) presented with PA. Patients with PA had longer disease duration, higher disease severity, and higher dopaminergic treatment. PA exhibited a higher prevalence of troublesome MFs (OR: 5.96; 95 % CI: 4.25-8.32) and LIDs (OR: 2.81; 95 % CI: 1.79-4.30), while associations with milder MCs were inconsistent. However, PA was not significantly associated with the development of MCs during follow-up.Conclusions: PA are associated with more frequent severe MCs, and a higher burden of motor and NMS, making patient care particularly challenging
TransformAR: A light-weight transformer-based metric for Augmented Reality quality assessment
No full textInternational audienceAs Augmented Reality (AR) technology continues to gain traction in various sectors, ensuring a superior user experience has become an essential challenge for both academic researchers and industry professionals. However, the task of automatically predicting the quality of AR images remains difficult due to several inherent challenges, particularly the issue of visual confusion arising from the overlap of virtual and real-world elements. This paper introduces transformAR, a novel and efficient transformer-based framework designed to objectively assess the quality of AR images. The proposed model uses pre-trained vision transformers to capture content features from AR images, calculates distance vectors to measure the impact of distortions, and employs cross-attention-based decoders to effectively model the perceptual qualities of the AR images. Additionally, the training framework uses regularization techniques and label smoothing-like method to reduce the risk of overfitting. Through comprehensive experiments, we demonstrate that transformAR outperforms existing state-of-the-art approaches, offering a more reliable and scalable solution for AR image quality assessment
