HAL Université de Toulouse, et Toulouse INP
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Controlling radiative properties of circular atomic arrays through nanofiber guided modes
No full textInternational audienceWe theoretically investigate the collective emission of one and two circular arrays of two-level atomssurrounding an optical nanofiber. We show that the radiation eigenmodes of a single ring selectively coupleto specific guided modes of the fiber, according to their symmetry, and study how the physical parameters of thesystem control their nature. In particular, we identify situations in which the emission toward radiation modesis highly suppressed with respect to fiber guided modes while the lifetime of the atomic excitation is enhanced.We further address the case of two identical rings positioned at a distance from each other along the nanofiber.By contrast to free-space configurations, the rings can exchange an excitation even at large separation throughnanofiber guided modes resulting in enhanced sub- and supper-radiance with respect to the single-ring case.Our findings suggest that the ring configuration is promising for the implementation of efficient and versatilelight-matter nanofiber-based interfaces and the achievement of waveguide quantum electrodynamics
Sizing and concentration analysis of cfDNA using Biabooster technology: Results from a prospective plasma‐based collection of 77 patients with locally advanced unresectable esophageal cancer
No full textInternational audienceAbstract Locally advanced esophageal carcinoma remains of poor prognosis correlated with tumor stage. Albeit liquid biopsy approach offers promising results to monitor high‐risk patients in various solid tumors, the lack of specific mutation in esophageal tumor, limits the detection of circulating tumor DNA (ctDNA) with high sensitivity using sequencing‐based methods. In this study, we employed a highly sensitive technology of fragmentome assay, previously validated to measure concentration and size distribution of cell‐free DNA (cfDNA), to analyze plasma samples from 77 patients with esophageal carcinoma, compared to 15 healthy controls. Total cfDNA concentration was significantly higher in patients than in healthy donors (15.03 ± 1.37 vs. 5.87 ± 0.85 pg/μL, p < .0001). The difference remained significant regardless of tumor histology, location, stage, or nodal involvement and was independent from age or gender. Additionally, we observed a significant reduction in patients fragment length compared to healthy donors. The area under curve from receiver operating characteristic (ROC) of total cfDNA concentration in patients versus healthy donors was 0.86 ( p ‐value <.0001). The threshold of 7.5 pg/μL yielded a sensitivity of 81% and a specificity of 80%. This prospective study demonstrated that blood samples from patients exhibit a greater global concentration of smaller fragments compared to healthy controls. These findings support further longitudinal evaluation to determine the predictive and prognostic value of cfDNA in locally advanced unresectable esophageal carcinoma
Aerosol dry deposition fluxes on snow during the ALPACA campaign in Fairbanks, Alaska
No full textInternational audienceA comprehensive study of aerosol exchange surface fluxes was conducted at a suburban site in Fairbanks (Alaska) during the Arctic winter as part of the ALPACA experiment. Aerosol fluxes were measured by an eddy covariance system on a snow-covered field located at the University of Alaska Fairbanks (UAF) Farm site from January 26 th to February 17 th , 2022. In general, bidirectional (emission and deposition) fluxes were measured at the site. Median deposition velocities were 0.61, 0.04, and 8.73 mm s⁻¹ for ultrafine (< 50 nm), accumulation (0.25 -0.8 µm), and quasi-coarse (0.8 -3 µm) particles, respectively. Anticyclonic synoptic meteorological conditions enhanced atmospheric stagnation and favoured pollutant accumulation near the surface, whereas cyclonic conditions increased aerosol dispersion, thus reducing deposition rates.Despite the frequent conditions of atmospheric stability and pronounced temperature inversions resulting from the strong surface radiative cooling, turbulence was generated mechanically by wind friction, leading to particle deposition. Our findings provide quantitative evidence that wintertime aerosol dry deposition in Arctic urban areas contributes significantly to pollutant accumulation in the snowpack, potentially enhancing contaminant remobilization during snowmelt. Finally, this study provides data for improving aerosol transport models and understanding pollutant-snow interactions in cold urban regions
Analyse de l'impact d'une application de jeu sérieux sur les élèves des lycées d'enseignement agricole
No full textNational audienceIn the last decade, the popularity of Serious Games has promoted both its research and application in several educational contexts. However, their application in the context of agricultural education has not been sufficiently explored, to the best of our knowledge. Moreover, agricultural education has seen a decrease on the number of students in the last 10 years. With the aim to increase the attractiveness of agricultural education, we propose the use of Serious Games. Consequently, we study the impact of a serious game adressed to technical agricultural high schools and to assess its impact on the following variables: self-efficacy, motivation, usability, and User Experience. This paper intents on exploring these impacts based on data collected from four technical agricultural secondary schools in France. The results show that there is a significant variation between the perceived self-efficacy of the students before and after they participated in the experiment. Moreover, we explore the cases of students that perceived their self-efficacy considerable different before and after the experiment. We also measured the usability, the user experience and analysed the correlations between these variables.Ces dernières années, la popularité des jeux sérieux a encouragé la recherche et leurs transpositions dans plusieurs contextes éducatifs. Cependant, à notre connaissance, il existe peu de jeux sérieux destinés à l'enseignement agricole. De plus, les effectifs de l'enseignement agricole ont progressivement diminué au cours des dix dernières années. Pour endiguer ce phénomène, les jeux sérieux représentent une double opportunité car ils permettent d'augmenter l'attractivité auprès des élèves et d'accélérer la transformation numérique des établissements. Notre étude est centrée sur l'impact d'un jeu sérieux destiné aux lycées professionnels agricoles et interroge les variables suivantes : sentiment d'auto-efficacité, motivation, utilisabilité et expérience utilisateur. Une expérimentation a été menée auprès de quatre lycées professionnels agricoles répartis sur le territoire français. Les résultats montrent qu'il existe une variation significative entre le sentiment d'auto-efficacité perçu par les élèves avant et après l'utilisation du jeu sérieux. De plus, nous explorons le cas des élèves dont le sentiment d'auto-efficacité a subi une forte variation (avant versus après l'expérience). Nous avons aussi mesuré l'utilisabilité, l'expérience utilisateur et analysé les corrélations entre ces variables
Alerte aux canicules marines
No full textLes vagues de chaleur marines existent depuis des décennies. Mais elles ont tendance désormais à être plus longues, plus fréquentes et plus impactantes pour l'environnement comme pour l'économie
Régulations du repliement des chromosomes basées sur l'ARN Pol II
No full textInternational audienceThe spatial organization of eukaryotic genomes and its dynamics are of functional importance for gene expression, DNA replication and segregation. SMC complexes are essential instruments of chromosome folding, enabling long-distance intra-chromatid DNA loops. The interplay between these processes is complex. For instance cohesin, in addition to tether sister chromatids, dynamically regulates gene expression in mammals by promoting interaction between distal regulatory elements and promoters, whereas transcription itself affects genome folding in many ways. Here, we comprehensively dissect the relative contributions of transcription and cohesin complexes, as well as their interplay, on the yeast S. cerevisiae genome organization. In particular, we show that transcription: (i) is not a motor required to push cohesin during DNA loop expansion, (ii) specifically induces the appearance of DNA loops independently of SMC complexes, and (iii) interferes with cohesin-mediated DNA loop expansion during their establishment
Direct recycling of NMC-cathode Scrap: Relithiation in aqueous solution following by low-temperature annealing
No full textInternational audienceWith the rise of electric mobility, the growing demand for batteries is expected to generate a significant stock of end-of-life batteries, making recycling an interesting solution to reduce environmental impact. Here, we propose a direct regeneration process in two steps based on a hydrothermal relithiation and post-annealing at moderate temperature. Two NMC-materials went through chemical delithiation and subsequent relithiation: NMC from scrap, which is recovered with the conductive carbon from its original formulation and reference NMC for comparison. The results demonstrate that relithiation was effective during the first solution step, leading to a partially active material. The post-annealing treatment enhances electrochemical performances and the best ones are obtained for the samples annealed at 400°C. Therefore, the results confirm that the presence of residual carbon does not impact relithiation or compromise its efficiency. The latter conserves its conductive properties after the relithiation process. However, an amount of the carbon has been lost during the second step; then this loss was compensated with an addition of fresh carbon, providing satisfactory electrochemical performances
Prevention of aspiration pneumonia recurrences
No full textInternational audienceContext: Aspiration pneumonia occurs after a documented aspiration or in patients with aspiration risk factors, suggesting a potential oropharyngeal portal of entry for the responsible pathogens. Strategies aimed at preventing recurrences are based on the identification of risk factors, their modification, and the implementation of appropriate corrective measures.Methods: A comprehensive review of the literature (2000-2025) on the prevention of aspiration pneumonia was conducted.Results: Treatments likely to exacerbate swallowing disorders must be reassessed, particularly anticholinergics, sedatives, and psychotropic drugs. No treatment was significantly effective in directly preventing aspiration pneumonia. Nutritional requirements are met using enteral nutrition, but it increases oral bacterial colonization, oral biofilm thickness, and muscle weakness. A series of measures (semi-sitting positioning in patients with impaired awareness or enteral nutrition, speech therapy, rehabilitation, and elimination of dental biofilm) were significantly effective in preventing aspiration pneumonia. Adapting food texture and thickening liquids are measures being considered to reduce the risks, despite the potential impact on the quality of life and on nutritional intake.Conclusion: A multidisciplinary assessment is recommended after an episode of pneumonia in the elderly to identify the pathogen's route of entry and to establish a plan to prevent recurrences. Future research will need to determine priorities among the various measures proposed to optimize management strategies
Mismatches between the current marine Natura 2000 network and seabird distributions call for enhanced protected areas off metropolitan France
No full textInternational audienceSeabirds are among the most threatened vertebrates, under pressure from fisheries bycatch, climate change, overfishing, and human disturbance. In France, demographic studies have highlighted adult survival as a key factor in population trends, which calls for large-scale marine conservation efforts. In this context, the Natura 2000 policy requires the designation of Special Protection Areas (SPAs) to protect seabirds under the Birds Directive. To assess the completeness of the French marine SPA network, data from aerial, boat, and coastal surveys, as well as tracking devices and distribution models, were collected for 57 seabird taxa. This data collection allowed the EU minimum criteria for a coherent SPA network to be spatially implemented, and the most ecologically valuable areas for seabirds around metropolitan France to be identified and prioritised, and overlaid with the current French SPA network and Marine Important Bird Areas (mIBAs) to identify potential inconsistencies. This analysis revealed seabird hotspots outside the existing ecological network, confirming some insufficiencies for coherent seabird conservation. Although data dependent, this analysis highlighted the limitations of using global proportion coverage to assess network coherence when coverage of biodiversity and abundance hotspots was not achieved. Furthermore, these results summarised the main target areas for policy makers to effectively improve seabird conservation around metropolitan France. In a context of increasing demands for marine spatial planning, improvements in this knowledge, the SPA network and conservation actions are required