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Investigation of the interaction mechanisms between natural dyes and hair fibers
No full textInternational audienc
Redox gradient shapes the chemical composition of peatland microbial communities
No full textInternational audienceThe response of soil carbon to climate change and anthropogenic forcing depends on the relationship between the physicochemical variables of the environment and microbial communities. In anoxic soils that store large amounts of organic carbon, it can be hypothesized that the low amount of catabolic energy available leads microbial organisms to minimize the energy costs of biosynthesis, which may shape the composition of microbial communities. To test this hypothesis, thermodynamic modeling was used to assess the link between redox gradients in the ombrotrophic peatland of the Marcell Experimental Forest (Minnesota, USA) and the chemical and taxonomic composition of microbial communities.The average amino acid composition of community-level proteins, called hereafter model proteins, was calculated from shotgun metagenomic sequencing. The carbon oxidation state of model proteins decreases linearly from -0.14 at 10 cm depth to -0.17 at 150 cm depth. Calculating equilibrium activities of model proteins for a wide range of chemical conditions allows identifying the redox potential of maximum chemical activity. Consistent with redox measurements across peat soils, this model Eh decreases logarithmically from an average value of 300 mV at 10 cm depth, close to the stability domain of goethite relative to Fe2+, to an average value of -200 mV at 150 cm, within the stability domain of CH4 relative to CO2. The correlation identified between the taxonomic abundance and the carbon oxidation state of model proteins enables predicting the evolution of taxonomic abundance as a function of model Eh. The model taxonomic abundance is consistent with the measured gene and taxonomic abundance, which evolves from aerobic bacteria at the surface including Acidobacteria, Proteobacteria, and Verrumicrobia, to anaerobes at depth dominated by Crenarchaeota.These results indicate that the thermodynamic forcing imposed by redox gradient across peat soils shapes both the chemical and taxonomic composition of microbial communities. By providing a mechanistic understanding of the relationship between microbial community and environmental conditions, this work sheds new light on the mechanisms that govern soil microbial life and opens up prospects for predicting geochemical and microbial evolution in changing environments
Multi-techniques characterisation of anti-reflective Ta2O5 and TaOxNy thin films deposited by reactive sputtering: coupling X-ray photoelectron spectroscopy, scanning/transmission electron microscopy and ion beam analysis
No full textInternational audienceTaOxNy thin films were elaborated by reactive magnetron sputtering of a Ta target in an Ar/N2/O2 plasma mixture. These layers are intended to be used as antireflective coatings in systems for concentrated solar applications (operating temperature around 500 degrees C in air). The investigation of these layers using a set of complementary techniques, including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ion beam analysis (IBA), revealed the impact of nitrogen flux during deposition on the overall morphology and elemental composition. These characterizations also highlighted the various chemical environments constituting the thin films, ranging from oxidized environments (Ta2O5) to oxynitride and nitride environments (TaOxNy and Ta3N5). It was also shown that with a low nitrogen flow, nitrogen is present only near the substrate and is absent in the rest of the layer. The IBA technique was also carried out to quantify the concentration of light elements as a function of depth, in particular H, which is not detected by the other techniques used in this paper (XPS and TEM). It has been shown that the majority of hydrogen atoms is incorporated into thin films during deposition as hydroxyl groups or only close to the surface, depending on the samples
Searches for signatures of ultra-light axion dark matter in polarimetry data of the European Pulsar Timing Array
No full textInternational audienceUltra-light axion-like particles (ALPs) can be a viable solution to the dark matter problem. The scalar field associated with ALPs, coupled to the electromagnetic field, acts as an active birefringent medium, altering the polarisation properties of light through which it propagates. In particular, oscillations of the axionic field induce monochromatic variations of the plane of linearly polarised radiation of astrophysical signals. The radio emission of millisecond pulsars provides an excellent tool to search for such manifestations, given their high fractional linear polarisation and negligible fluctuations of their polarisation properties. We have searched for the evidence of ALPs in the polarimetry measurements of pulsars collected and preprocessed for the European Pulsar Timing Array (EPTA) campaign. Focusing on the twelve brightest sources in linear polarisation, we searched for an astrophysical signal from axions using both frequentist and Bayesian statistical frameworks. For the frequentist analysis, which uses Lomb-Scargle periodograms at its core, no statistically significant signal has been found. The model used for the Bayesian analysis has been adjusted to accommodate multiple deterministic systematics that may be present in the data. A statistically significant signal has been found in the dataset of multiple pulsars with common frequency between Hz and Hz, which can most likely be explained by the residual Faraday rotation in the terrestrial ionosphere. Strong bounds on the coupling constant , in the same ballpark as other searches, have been obtained in the mass range between eV and eV. We conclude by discussing problems that can limit the sensitivity of our search for ultra-light axions in the polarimetry data of pulsars, and possible ways to resolve them
The Tectonic Responses in the Overriding Plate During the Tethyan Convergence and the Progressive Extrusion Process in Sundaland: Insights From the Wuliangshan Massif, SE Tibetan Plateau
No full textInternational audienceThe overriding plate commonly accumulates less strain than the subducted plate during continental collision. Analyzing plate interactions from the perspective of the overriding plate provides important insights into orogenic dynamics. In the southeastern Tibetan Plateau, the Wuliangshan massif, as a key region of the overriding plate, records tectonic events related to the closure of both the Paleo-Tethys and Neo-Tethys. In this study, we present detailed structural analysis, Titanium-in-quartz geothermometry, and zircon U-Pb and Hf isotopic data. These results indicate that the Wuliangshan massif experienced rapid subsidence and deposition within a short period from 260 to 250 Ma in a back-arc tectonic setting. The polyphase deformation events were recognized in the Wuliangshan massif. The ductile syn-metamorphism D 1 event, characterized by a top-to-the-SE ductile shearing under middle-to high-temperature conditions, represents the tectonic response to the collision between the Sibumasu block and the Indochina block occurred at ca. 250-246 Ma. The D 2 deformation is expressed by E-directed thrusts and E-verging folds coeval with a slaty cleavage. The D 3 deformation is marked by SW-directed thrusts and SW-verging folds. The D 2 and D 3 events correspond to positive flower structures related to transpression along the Chongshan-Lancang River fault and the Ailaoshan-Red River fault, respectively. The D 2 -related Chongshan-Lancang River fault accommodated the southward extrusion of the western part of Sundaland occurred at 32-27 Ma. The southeastward extrusion of the entire Sundaland was accommodated by the D 3 -related Ailaoshan-Red River fault at 27-23 Ma.</div
Un tarot philosophique à l'appui d'une recherche-action au service de l'auto-formation d'enseignantes en maternelle
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Sciences archéologiques et statistiques: Questions, données, méthodes
No full textNational audienceLes statistiques sont partie intégrante du raisonnement archéologique, pour structurer des ensembles d’information archéologique, pour établir des ordres de grandeur ou encore mettre en relation différents processus afin de proposer des interprétations de phénomènes passés. Dans la pratique, l’approche statistique engage, de manière sous-jacente, des concepts archéologiques liés au questionnement, repose sur l’identification d’éléments empiriques correspondants, utilise des méthodes statistiques pour l’analyse. C’est donc un dialogue entre archéologie et statistiques auquel nous sommes conviés, qui ne peut pas être réduit à sa simple expression technique.Face à un enjeu de sensibilisation et de transmission des connaissances des pratiques statistiques pour l’archéologie, cet ouvrage offre une approche didactique interdisciplinaire accessible aux non-spécialistes. Réciproquement, il permettra aux statisticiens d’appréhender la manière dont les archéologues transcrivent une problématique plus ou moins complexe en un schéma d’analyse statistique. Dans une première partie, nous partons des questions que se posent les archéologues lorsqu’il s’agit de reconstituer des chronologies, de comprendre les dynamiques spatiales, de lire des informations anthropologiques. Des exemples d’études sont présentés sous l’angle de trois dimensions articulées autour des questions « Quand ? », « Où ? », « Qui/Quoi ? ». Dans une deuxième partie, nous invitons le lecteur à approcher les méthodes statistiques, des plus simples aux plus élaborées. En réunissant les contributions de spécialistes de la chronologie, de la culture matérielle, de la géographie du passé, de l’anthropologie biologique, de la paléontologie et de la statistique, cet ouvrage propose un panorama non exhaustif d’études de cas qui, à travers la diversité des objets empiriques et des approches statistiques mobilisés, éprouvent les méthodes et les conditions d’application des outils non sans aborder apports et limites interprétatifs.Cet ouvrage s’adresse aux apprenants comme aux praticiens, étudiants et scientifiques intéressés par la mobilisation de méthodes statistiques pour répondre à des problématiques archéologiques. Il a pour ambition de décloisonner les approches en offrant à chacun des pistes de réflexion quel que soit le niveau de lecture
Effects of concentric and concentric-eccentric resistance training on speed and force in adult soccer players
No full textInternational audienceThis study investigated the effects of concentric and concentric-eccentric strength training on speed and strength performance in sub-elite soccer players. Thirty-four healthy Czech soccer players were randomly assigned to a concentric group (CONG, n = 13), concentric/eccentric group (ECCG, n = 12), or control group (CG, n = 9). All participants completed the study. Over an 8-week intervention period, the CONG and ECCG groups accomplished 16 training sessions focused on leg curl and leg extension exercises. Speed and strength assessments were performed at baseline and post-intervention. While no significant improvements were observed in speed performance (p > 0.05), both intervention groups demonstrated significant gains in strength parameters. One-repetition maximum (1RM) knee extension increased by 17.5% (CONG, p < 0.001) and 18.3% (ECCG, p < 0.001), and the 1RM knee flexion improved by 10.5% (CONG, p < 0.001) and 12.2% (ECCG, p < 0.001, compared to the CG, with moderate and clear effect sizes. ANOVA analysis revealed significant interaction effects for knee extension 1RM (p < 0.001), knee flexion 1RM (p = 0.022), and isometric knee extension of the dominant leg (p = 0.033). Despite these gains in muscle strength, speed performance showed only minor, non-significant changes, with the CONG group experiencing a 2.8% improvement in the 10-meter sprint. In conclusion, both concentric and concentric-eccentric strength training protocols effectively enhanced lower-limb strength in soccer players, with the concentric-eccentric approach showing slightly better results. However, neither training method significantly improved speed. Coaches should use concentriceccentric exercises to enhance strength but consider other methods to boost speed and overall performance.</div
Exact Evaluation of the Accuracy of Diffusion Models for Inverse Problems with Gaussian Data Distributions
No full textUsed as priors for Bayesian inverse problems, diffusion models have recently attracted considerable attention in the literature. Their flexibility and high variance enable them to generate multiple solutions for a given task, such as inpainting, super-resolution, and deblurring. However, several unresolved questions remain about how well they perform. In this article, we investigate the accuracy of these models when applied to a Gaussian data distribution for deblurring.Within this constrained context, we are able to precisely analyze the discrepancy between the theoretical resolution of inverse problems and their resolution obtained using diffusion models by computing the exact Wasserstein distance between the distribution of the diffusion model sampler and the ideal distribution of solutions to the inverse problem. Our findings allow for the comparison of different algorithms from the literature
Patient–Practitioner–Environment Synchronization: Four-Step Process for Integrating Interprofessional and Distinctive Competencies in Osteopathic Practice—A Scoping Review with Integrative Hypothesis
No full textInternational audienceBackground. A major goal for a significant portion of the osteopathic community is to update osteopathic principles, satisfying three needs: sourcing from the origin, proposing original and unique practical approaches, and describing the entire process in a scientifically updated way. On this line, several interprofessional proposals for healthcare providers have already been made by implementing patient-centered care and touch-based strategies informed by the enactive model. Enactivism principles can provide a foundation for rethinking osteopathic care by integrating environmental, psychological, social, and existential factors to facilitate the patient’s biobehavioral synchronization with the environment and social context, address health needs, and enhance the quality of multiprofessional healthcare services. However, there is a need to develop a conceptual model that offers a framework for organizing and interpreting disciplinary knowledge, guiding clinical observation and practical strategies, and defining both interprofessional collaboration and the unique focus of the profession. This scoping review and integrative hypothesis aim to fulfill the need for a more detailed and comprehensive understanding of the distinctive osteopathic care to biobehavioral synchrony, emphasizing both interprofessional collaboration and the profession’s unique competencies. Methods. The present article was developed in accordance with established guidelines for writing biomedical scoping reviews. Results. A total of 36 papers were considered for thematic and qualitative analyses, which supported the integrative hypothesis. Considering the current tenets for osteopathic rational practice, we propose an integrative hypothesis to focus on a practical framework for osteopathic patient biobehavioral synchronization. Patient–practitioner–environment synchronization could be promoted through a four-step process: (1) a narrative-based sense-making and decision-making process; (2) a touch-based shared sense-making and decision-making process; (3) hands-on, mindfulness-based osteopathic manipulative treatment; (4) patient active participatory osteopathic approaches to enhance person-centered care and rational practice. Conclusions and future directions: The proposed model fosters patient–practitioner synchronization by integrating updated traditional osteopathic narratives and body representations into practice, offering a culturally sensitive approach to promoting health, addressing contemporary health needs, and improving inclusive health services. Future studies are required to assess the transferability and applicability of this framework in modern settings worldwide