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Une nouvelle distance multi-experte pour le partitionnement automatique des paramètres climatiques : une étude de cas sur les précipitations dans les Caraïbes
No full textInternational audienceThis study investigates precipitation patterns in the Caribbean region using a novel Multi-Expert Distance (MED) metric for clustering analysis. MED integrates multiple climate parameters, including Sea Surface Temperature (SST), wind components at 925 hPa, and Outgoing Longwave Radiation (OLR), with the objective of enhancing spatiotemporal precipitation analysis. This approach offers an alternative to conventional methods that rely on single datasets and Euclidean distances. It combines physical parameters during clustering to enhance accuracy and insights. The analysis encompasses a 43-year period (1979-2021), extending from the Gulf of Mexico to the Caribbean, with a spatial extent that covers the entire region. The MED metric incorporates zone-specific his-tograms and Kullback-Leibler divergence, enabling dynamic comparisons of atmospheric configurations. The analysis yielded six distinct clusters, each exhibiting unique seasonal and inter-annual precipitation patterns, influenced by regional atmospheric dynamics. The analysis revealed significant transitions and associations between clusters, precipitation levels, and atmospheric conditions. Clusters representing dry conditions exhibited negative SST anomalies, reflecting reduced moisture production. Conversely, clusters exhibiting high precipitation exhibited positive SST anomalies, which are conducive to moisture accumulation. Furthermore, tropical storms and hurricanes were predominantly observed in wetter clusters, underscoring the utility of MED in linking atmospheric phenomena with climatic impacts. The results highlight the effectiveness of the MED in improving both the accuracy and interpretability of clustering algorithms. Beyond its methodological contributions, this work highlights the MED's potential to advance the understanding and forecasting of precipitation regimes, thereby contributing to more robust climate analyses. Such insights are particularly relevant for informing climate adaptation strategies in vulnerable regions, notably the Caribbean. Future research could investigate automated domain segmentation as a means of further refining and optimizing this approach.Cette étude examine les régimes de précipitations dans la région des Caraïbes en utilisant une nouvelle métrique appelée Distance Multi-Expert (MED) pour l’analyse par regroupement. La MED intègre plusieurs paramètres climatiques, notamment la température de surface de la mer (SST), les composantes du vent à 925 hPa et le rayonnement infrarouge sortant (OLR), dans le but d’améliorer l’analyse spatio-temporelle des précipitations. Cette approche constitue une alternative aux méthodes conventionnelles reposant sur des ensembles de données uniques et des distances euclidiennes. Elle combine des paramètres physiques lors du regroupement afin d’accroître la précision et la pertinence des résultats.L’analyse couvre une période de 43 ans (1979–2021), s’étendant du golfe du Mexique aux Caraïbes, avec une couverture spatiale englobant toute la région. La métrique MED intègre des histogrammes spécifiques à chaque zone ainsi que la divergence de Kullback-Leibler, permettant des comparaisons dynamiques des configurations atmosphériques. L’étude a permis d’identifier six groupes distincts, chacun présentant des régimes de précipitations saisonniers et interannuels uniques, influencés par les dynamiques atmosphériques régionales. Elle a révélé des transitions significatives et des associations entre les groupes, les niveaux de précipitations et les conditions atmosphériques. Les groupes représentant des conditions sèches présentaient des anomalies négatives de SST, traduisant une production d’humidité réduite. À l’inverse, les groupes caractérisés par de fortes précipitations affichaient des anomalies positives de SST, favorables à l’accumulation d’humidité. De plus, les tempêtes tropicales et les ouragans ont été principalement observés dans les groupes les plus humides, soulignant l’utilité de la MED pour relier les phénomènes atmosphériques aux impacts climatiques. Les résultats mettent en évidence l’efficacité de la MED pour améliorer à la fois la précision et l’interprétabilité des algorithmes de regroupement. Au-delà de ses contributions méthodologiques, ce travail souligne le potentiel de la MED pour faire progresser la compréhension et la prévision des régimes de précipitations, contribuant ainsi à des analyses climatiques plus robustes. Ces connaissances sont particulièrement pertinentes pour orienter les stratégies d’adaptation climatique dans les régions vulnérables, notamment les Caraïbes. Des recherches futures pourraient explorer la segmentation automatisée des domaines comme moyen d’affiner et d’optimiser davantage cette approche
Automated classification of subsurface impact damage in thermoplastic composites using depth-resolved terahertz imaging and deep learning
No full textInternational audienceReliable detection of barely visible impact damage is critical to ensure the structural integrity of composite components in service, particularly in safetycritical applications such as pressure vessels and transportation systems. This study presents a solution for detecting such damage in woven glass fiberreinforced thermoplastic composites using terahertz (THz) time-of-flight tomography and convolutional neural networks. THz provides non-contact, non-ionizing, high-axial-resolution imaging of subsurface and back-surface damage, addressing key limitations of surface-based inspection methods. While THz imaging alone may not always permit conclusive damage identification, we bridge this gap by training neural network classifiers on depthresolved THz B-scan images using ground truth from co-located X-ray microcomputed tomography. Among several pretrained architectures tested via transfer learning, DenseNet-121 exhibits the highest accuracy. The model remains robust even when trained on truncated B-scans excluding surface indentation features, confirming its ability to detect structural anomalies located internally or on the back surface. This is particularly relevant for applications where back-side access is not feasible. Experimental validation is performed on impacted glass-fiber-reinforced thermoplastic coupons prepared in accordance with ASTM D7136, with damage severity quantified through force-displacement data and micro-tomographic analysis. Labeling for supervised learning conforms to acceptance criteria from industrial standards for composite pressure vessels (ASME BPVC Section X, CGA C-6.2), ensuring regulatory alignment and enabling deployment in quality control workflows. The proposed method minimizes the need for expert interpretation or secondary validation and offers direct applicability to in-service inspection and manufacturing quality control
Health monitoring of NiTi endodontic instruments using acoustic Emission: Spectral indicators for predictive damage detection
No full textInternational audienc
Environmental consequences of genetic improvements of growth and fillet yield in gilthead seabream: A life cycle assessment from breeding to plate
No full textInternational audienceSelective breeding plays a key role in the sustainable development of aquaculture by improving productivity and efficiency. While breeding programs have initially focused on growth traits, their potential to mitigate the environmental footprint of fish farming remains poorly explored. Here, we present a case-study on the environmental consequences of selective breeding during five generations (15 years) for growth and fillet yield in gilthead sea bream Sparus aurata by integrating genetic gain projections into a full supply chain Life Cycle Assessment (LCA), extending from hatchery to final consumer. The potential impacts were calculated in terms of 1 tonne of fish produced at the farm level and were also expressed per tonne of flesh consumed. Performance data and genetic parameters from families in a seabream breeding program were used to estimate breeding values under different selection scenarios. Selection for growth significantly shortened the production cycle, while selection for fillet yield increased the proportion of edible product. Although environmental gains at the farm level were modest (<1 %), substantial reductions (up to 7 % in climate change impacts and cumulative energy demand) were observed when impacts were expressed per tonne of fillet consumed. Feed production and consumption remained the dominant source of environmental burden across all scenarios. By explicitly accounting for post-farm stagesprocessing, distribution, consumption, and waste management -our study demonstrates that genetic improvement, particularly for fillet yield, can meaningfully reduce the environmental footprint of aquaculture products delivered to the consumer. This case study underlines the importance of integrating full supply chain assessments into genetic selection strategies to drive sustainable breeding in aquaculture
One pot synthesis of ZnO nanoparticle/mesoporous silica nanocomposite for photocatalysis
No full textInternational audienceMetal oxide materials, such as ZnO, have attracted considerable interest in photocatal-ysis due to their ability to generate reactive species under UV irradiation, which are useful for the degradation of organic or inorganic pollutants. However, the efficiency of photocatalysis re-lies on the intrinsic properties of the photocatalyst, such as its specific surface area or stability, or even aggregation when it is in the form of nanoparticles. To address these issues, we synthesized and thoroughly characterized ZnO nanoparticles confined in a mesoporous silica matrix. Several synthesis parameters were investigated, including the method of silica synthesis, the nature of the zinc precursor and the calcination temperature. The resulting materials exhibited a large specific surface area, and nanoparticles of 2 nm were homogeneously dispersed within the silica matrix. The optical properties, UV–visible absorption and photoluminescence, were examined and photocatalytic properties were evaluated through the photoreduction of Cr(VI)
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
Peppermint interplanting and nitrogen fertilisation for green peach aphid management in peach orchards: Field evidence of VOC-mediated effects
No full textInternational audienceA potential strategy for reducing pesticide applications within a cropping system is the use of agroecological practices to alter pest behaviour. Among these practices are the use of companion plant and the management of nitrogen fertilisation. Companion plants (CPs) emit volatile organic compounds (VOCs) that can influence aphid behaviour. Nitrogen fertilisation may affect aphid feeding and, consequently, aphid population growth, as it alters plant composition and development. The objective of this study was to determine whether the combination of nitrogen fertilisation and Mentha × piperita ground cover could modify the incidence of Myzus persicae in a peach orchard. We conducted a factorial experiment quantifying M. persicae incidence, VOC emissions, Prunus persica growth, and agronomic performance under contrasting nitrogen levels, with or without Mentha × piperita cover. This study provides field evidence of peppermint VOC production. We identified specific volatile compounds around peach trees associated with peppermint, including menthone, menthyl acetate, and eucalyptol. A high nitrogen level increased peppermint VOC emissions, reduced M. persicae incidence, and enhanced peach tree growth. The peppermint cover appeared to slightly improve the visual appearance of fruits at harvest. Fruits quality remained within commercial standards in terms of sugar content and overall yield, and fruit size was not significantly reduced despite potential resource competition with peppermint. Further research is needed to better understand the specific factors influencing VOC emissions and their effects on aphids at a finer temporal scale
Cyclodextrin-in-Liposome for therapy: Advances and challenges
No full textInternational audienceThe concept of drug-in-cyclodextrin-in-liposomes (DCLs) was introduced to the scientific community thirty years ago by McCormack and Gregoriadis (1994). Since then, there have been ongoing advances in cyclodextrin (CD) and liposome technology. Various CD derivatives and subtypes of liposomes have emerged. CDs are known nowadays as sequestering agents of cholesterol from tissues and as solubilizers of many hydrophobic active compounds. However, CDs have poor bioavailability, which limits their oral administration. Moreover, CD/drug inclusion complexes are limited as controlled delivery systems due to their rapid dissociation in blood. On the other hand, hydrophobic drugs embedded in the lipid bilayer of liposomes may affect the lipid membrane stability and exhibit a low loading rate. This review focuses on the advantages that CD-in-liposomes (CLs) offer to the medical field as carriers that can transport CDs in either their free forms or as CD/drug inclusion complexes. Liposomes can also embed specific molecules on their surfaces, enabling targeting, which remains to date a challenge for modified CDs. This review summarizes the literature on the use of CL- or DCL-based formulations aimed at treating certain diseases and the mechanisms underlying their distribution and function
An “orthorexic society”: The role of psychological flexibility in responding to healthy eating pressures
No full textInternational audienceIn some countries, public health policies and social networks are contributing to making people more responsible for their own health by promoting healthy eating. This context of "healthism" has witnessed the development of orthorexia nervosa. Described as an eating disorder based on an obsession with healthy eating, orthorexia nervosa is not yet included in diagnostic manuals. A central issue in the study of orthorexia is how it differentiates from other eating disorders and how to identify it among the growing number of healthy diets. Flexibility seems to be relevant for distinguishing between the adaptive and pathological forms of adherence to eating habits perceived as healthy. In this respect, psychotherapeutic interventions linked to flexibility are a promising path to support people with orthorexic symptoms, regardless of disorder categorization. Flexibility could also be integrated into the way dietary recommendations are devised, in order to promote the overall physical, psychological and social health