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Effets de la taille et de l’indépendance du Conseil d’Administration sur la performance des sociétés endettées
No full textInternational audienceCet article s’intéresse aux relations entre la structure du CA et la performance des sociétés endettées. L’endettement, comme moyen de contrôle du dirigeant et facteur de complexité, est considéré comme une problématique majeure en gouvernance financière. L’article propose d’étudier l’effet de la taille et de l’indépendance du CA sur la performance des sociétés endettées. L’étude statistique repose sur les sociétés appartenant à l’indice CAC All-Tradable entre 2015 et 2019. Les résultats démontrent surtout qu’il n’est pas dans l’intérêt financier des sociétés endettées d’opter pour des CA de taille importante et majoritairement indépendants
Lycopene from tomato biomass: Extraction and stabilization
No full textInternational audienceLycopene and other carotenoids have a significant added value in the food and cosmetic industries due to their nutraceuticalproperties and antioxidant activity. The extraction and stabilization of these compounds remain challenging due to theirsensitivity to light, temperature fluctuations, and oxidation. This article introduces a sustainable method of extracting lycopenefrom tomato waste (Solanum lycopersicum L.) using layered double hydroxide nanoparticles to stabilize lycopene.We used tomato juice and lycopene as a positive control, while ZnAl was a negative control. The experimental samples included75 and 100 mg of zinc salt per 1 mL of tomato juice, which were labeled as ZnAl75J and ZnAl100J.Zinc and aluminum salts developed insoluble hydroxides, which precipitated lycopene from tomato juice, thus formingcomposites. The composites proved to be efficient means of encapsulating lycopene as they recovered 97% lycopene presentin tomato juice. The physicochemical properties of the organic material enhanced resistance to thermal degradation and actedas an extended-release antioxidant. ZnAl100J, which contained a lot of lycopene, inhibited 89% of DPPH• in 24 h and showeda value higher than IC50 for ABTS•+, which was 0.02 μg/mL of TEAC ABTS•+. ZnAl75J composites showed a higher protectionagainst oxidation and a higher sun protection factor value (3.08) at 15% concentration.The composites could be used as an active ingredient in a wide range of formulations that require antioxidant and photo-sensitizing properties, or simply as encapsulators and carriers of lycopene
Natural Deep Eutectic Solvents Design Acceleration Using Variational Auto Encoder
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Valorization of Sugar Beet Byproducts into Oligogalacturonides with Protective Activity against Wheat Powdery Mildew
No full textInternational audienceThe shift toward sustainable agriculture emphasizes the need for eco-friendly biocontrol strategies. Oligogalacturonides (OGs), which are pectin-derived cell wall fragments, are promising plant defense inducers. This study evaluated two OGs mixtures, obtained from sugar beet byproducts, for their protective effect against Blumeria graminis f. sp. tritici (Bgt), the causal agent of wheat powdery mildew. OGs were generated by hydrolyzing pectins with two Arabidopsis thaliana polygalacturonases, ADPG2 and PGLR, expressed in Pichia pastoris. OGs-ADPG2 showed a degree of polymerization (DP) 1-10 and esterification (DE) 41%, while OGs-PGLR had DP 1-16 and DE 34.5%. Although neither inhibited Bgt spore germination directly, OGs-PGLR provided 31% preventive protection. Both OGs activated defense-related genes, but only OGs-PGLR induced lipoxygenase (9-LOX), initiating the octadecanoic pathway and oxylipin production. Overall, these results highlight the potential of OGs derived from sugar beet byproducts as sustainable alternatives to reduce phytochemical use in crop protection
Ressources, changements climatiques et transition énergétique : impacts économiques et incidences des inégalités
No full textThis thesis analyses the impact of the energy transition on income inequality, focusing on the economic and environmental mechanisms involved in this process. One of the main contributions of this work is to demonstrate that, although the energy transition is essential for achieving climate objectives, it can also intensify economic disparities if policies are not properly adjusted to mitigate these unintended side-effects.The first chapter proposes a general equilibrium model that establishes a link between energy production and available resources (capital, land and labour). The changes in the price structure of production factors brought about by the energy transition affect households differently depending on their income level. The fall in the price of capital mainly benefits high-income households, which are better placed to invest in manufactured goods and advanced technologies. On the other hand, the rise in the price of land, caused by the increased demand for bioenergy production, leads to a rise in food prices, thus disproportionately affecting low-income households. Without compensatory measures, the energy transition will lead to greater inequality.Advanced biofuels, made mainly from waste oils and agricultural waste, allow us to relax the constraints on land use. They are not produced at the expense of food production, but rather as a way of recycling food waste. The second chapter focuses on the production of these advanced biofuels and their use in the aviation sector, where the impossibility of using electric power makes their usage, at least in the short term, essential to the transition. This chapter shows that the European ReFuelEU directive will help to reduce emissions from the sector. However, it highlights the need for careful management of the minimum level of sustainable aviation fuel imposed on airlines. Excessively high quotas could lead to such high demand for these biofuels that their manufacture from food products could prove more profitable than selling them for their primary purpose. In so doing, these advanced biofuels would have consequences similar to those of first-generation biofuels.Ultimately, this thesis makes a significant contribution to the analysis of the economic and social dynamics induced by the energy transition. It demonstrates that variations in the price of production factors - such as the fall in the cost of capital or the rise in land prices - have unequal repercussions depending on household income levels, thereby exacerbating economic disparities. Furthermore, by examining the potential of advanced biofuels and analysing the implications of the ReFuelEU directive, this thesis highlights the risk that poorly framed policies will simultaneously compromise climate objectives and food security. It therefore argues for the introduction of public policies that not only promote the energy transition, but also incorporate measures to reduce social inequalities and ensure the sustainability of socio-economic systems.Cette thèse propose une analyse des impacts de la transition énergétique sur les inégalités de revenus, en se concentrant sur les mécanismes économiques et environnementaux impliqués dans ce processus. L'une des principales contributions de ce travail réside dans la démonstration que, bien que la transition énergétique soit essentielle pour atteindre les objectifs climatiques, elle peut également intensifier les disparités économiques si les politiques ne sont pas correctement ajustées pour atténuer ces effets secondaires non intentionnels.Le premier chapitre propose un modèle d'équilibre général qui établit un lien entre la production énergétique et les ressources (capital, terre et travail) disponibles. Les changements dans la structure du prix des facteurs de production, induits par la transition énergétique, affectent différemment les ménages en fonction de leur niveau de revenu. La baisse du prix du capital bénéficie principalement aux ménages à revenu élevé, mieux positionnés pour investir dans les biens manufacturés et les technologies avancées. En revanche, la hausse du prix de la terre, provoquée par la demande accrue pour la production de bioénergie, entraîne une augmentation des prix alimentaires, affectant ainsi de manière disproportionnée les ménages à faible revenu. Sans mesures compensatoires, la transition énergétique entraine donc un renforcement des inégalités.Les biocarburants avancés, fabriqués principalement à partir des huiles usagées et des déchets agricoles, permettent de relâcher la contrainte sur l'utilisation des sols. En effet, leur production ne se fait pas au dépend de la production alimentaire, mais se présente au contraire comme une valorisation de ses déchets. Le second chapitre se concentre sur la production de ces biocarburants avancés et leur usage dans le secteur aéronautique, où l'impossibilité de recourir à l'énergie électrique, rend leur usage, au moins à court terme, indispensable à la transition. Ce chapitre montre que la directive européenne ReFuelEU pourra aider à réduire les émissions du secteur. Cependant, il met en évidence la nécessité d'une gestion prudente du niveau minimum de carburant d'aviation durable imposé aux compagnies. En effet, des quotas trop élevés pourraient entrainer une demande telle pour ces biocarburants que leur fabrication à partir de produits alimentaires pourrait s'avérer plus rentable que de la vente de ces derniers pour leur fin première. Ce faisant, ces biocarburants avancés auraient des conséquences similaires à celles induites par les biocarburants de première génération.En somme, cette thèse contribue à l'analyse des dynamiques économiques et sociales induites par la transition énergétique. En démontrant que les variations des prix des facteurs de production, telles que la baisse du coût du capital ou la hausse des prix de la terre, génèrent des impacts différenciés sur les ménages selon leurs niveaux de revenu, elle met en exergue les risques d'amplification des disparités économiques. Par ailleurs, en explorant les potentialités des biocarburants avancés et en intégrant les implications de la directive ReFuelEU Aviation, ce travail montre que, sans un encadrement normatif adapté et des incitations économiques adaptées, ces politiques risquent de compromettre simultanément les objectifs climatiques et la sécurité alimentaire. Elle invite donc à la mise en place de politiques publiques non seulement aptes à favoriser la transition énergétique mais également attentives à leurs conséquences sur les inégalités et la soutenabilité des systèmes socio-économiques
Recent Advances in Interfacial Liquid-Liquid Oxidation in Emulsions and Microemulsions with Surface-Active Molecular and Nanoparticulate Catalysts
No full textInternational audienceThis review presents recent advances in catalytic oxidations performed in emulsified biphasic systems using primary oxidants (O2, H2O2 and t-BuOOH) mediated by surface-active molecular or nanoparticulate catalysts. Emphasis is placed on the activation of these sustainable oxidants by redox catalysts compatible with aqueous biphasic environments. A distinctive feature of this review is its colloid-focused perspective, examining how the formulation and composition of surface-active catalyst/oil/water systems drives emulsion morphology, droplet size, demixing kinetics and ultimately the ease of product recovery and catalyst recycling. Particular attention is given to the design of redox-active amphiphiles which enhance interfacial coverage and facilitate (nano)emulsification. Three classes of systems are considered: (i) systems using separate phase-transfer agents and redox catalysts; (ii) integrated systems involving catalytic surfactants or catalytic ionic liquids that combine interfacial and redox functions within a single species and (iii) amphiphilic nanoparticles that adsorb at the oil-water interface, serving as both emulsion stabilizers (the so-called Pickering emulsions) and oxidation catalysts. A dedicated section addresses the challenge of chemically generated singlet oxygen (1O2) in organic synthesis. Due to its short lifetime in water (≈ 4 µs), 1O2 must be generated in aqueous nanodroplets of a microemulsion system to ensure its diffusion into the organic phase before deactivation occurs. Recent innovations in Pickering interfacial catalysis highlight that particle-based systems are becoming increasingly elaborated, both for controlling the physicochemical properties of the emulsion and for enhancing catalytic performance. However, several challenges still remain to be overcome before they can be scaled up for industrial applications
Nouvelles pistes sur le polynôme chromatique des matroïdes
No full textInternational audienceIn this poster, we introduce matroids and give clues to get the chromatic polynomial for matroids using a double bialgebra structure.For this purpose, we introduce a notion of restriction/contraction bialgebra for matroids
Inter- and intra-site variation of microarthropod communities in urban parks
No full textInternational audienceUrban parks are one of the most represented green spaces in cities and can support biodiversity. However, most of the studies demonstrating the role of urban biodiversity do not take into account soil biodiversity, which represents at least ¼ of the world's taxonomic diversity. Among these soil organisms, microarthropods are recognised bioindicators because of their role in soil functioning but also because of their high abundance and sensitivity to a variety of environmental and anthropogenic factors. With high heterogeneity due to soil, management or localisation, nothing looks less like a park than another park. In this study, our aim is rather to understand how soil biodiversity is affected by the spatial configuration of the parks. To do this, we studied interand intra-park variation in microarthropod communities using taxonomic and functional approaches based on traits. Our results show communities dominated by Acari, with high abundances of Collembola but low specific richness. Inter-park variations were recorded for the species richness and functional composition of Collembola, Oribatidae abundance, texture and metal levels. That may be linked to the age of the sites in relation with soil physicochemical parameters. Intra-park variations were also observed, particularly for biodiversity indices, which could be explained by the fragmentation of the site and patch size. Despite their small size, soil organisms should be considered in park studies and design (configuration and connectivity). Indeed, understanding the distribution patterns of these organisms is important for improving the role of parks within a functional green and brown urban network
All pet owners are not the same: End-of-Life caregiver expectations and profiles
No full textInternational audienceThe study aims to explore the specific needs of French pet owners who have experienced the loss of a pet, recognizing the limited focus on end-of-life and palliative care in veterinary practice. By characterizing owner profiles, the research seeks to enhance veterinary approaches and education to better address the unique challenges and emotional aspects associated with pet care and loss. An anonymous online survey was distributed to 302 French owners who already experienced the loss of an animal, including demographic information and feelings about their experience of a pet's end-of-life (EOL). Data were analysed using descriptive and qualitative analysis (including the use of AI chatbot ChatGPT). 56.6 % of participants reported a relatively smooth pet death, yet 67.0 % found the end-of-life period challenging. Three distinct owner groups emerged, each with varying needs. The first group expressed high guilt and a greater need for support, emphasizing the necessity for information and improved training. The second group, more informed and independent, benefits from veterinary support, while a leaflet suits them. The third group, competent in pain evaluation, requires less veterinary support. These differences highlight the importance of personalized owner support. The study proposes essential pillars for veterinarians and nurses' training, forming the EPITO system
A green approach combining polyelectrolyte-based core-shell microparticles and laccase for indigo carmine degradation
No full textInternational audienceHighly effective composite biocatalysts were developed by the immobilization of laccase (LAC), a copper oxidoreductase, on core-shell microparticles obtained by the layer-by-layer deposition of polyelectrolytes, SP/ (PEI/PAA) 4.5 and SP/(PEI/PMANa) 4.5 . The relation designpropertiesapplications was successfully elucidated by a comprehensive characterization performed using a combination of scanning electron microscopy (SEM), atomic force microscopy (AFM), potentiometric titrations, energy dispersive X-ray (EDX) spectroscopy and catalytic activity assays. The core-shell composite microparticles were able to immobilize more than 50 % of the enzyme, conserving a satisfactory enzymatic activity. LAC@SP/(PEI/PAA) 4.5 and LAC@SP/(PEI/PMANa) 4.5 were further employed in the degradation of indigo carmine as a model pollutant under various experimental conditions. The influence of the amount of enzyme immobilized, the pH, the mediator and the dye concentration were assessed, observing that LACn@SP/(PEI/PAA) 4.5 and LACn@SP/(PEI/PMANa) 4.5 performed better when syringaldehyde was used as a mediator. The obtained immobilized LAC achieved 100 % discoloration efficiency, demonstrating their potential as green catalysts for water cleaning applications. Additionally, the immobilized LAC exhibited significantly enhanced stability upon reuse, being able to completely discolour the dye sample up to 4 reuse cycles.</div