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Le stockage en super-réfrigération réduit la croissance et la diversité des communautés bactériennes associées aux filets de saumon de l’Atlantique (Salmo salar)
No full textThe data were shared. Raw reads have been deposited in the Sequence Read Archive (SRA) under the project accession number PRJNA1233232.International audienceSuperchilling is an innovative preservation technique that maintains food products at temperatures between conventional refrigeration and freezing. It addresses the challenge of minimizing food spoilage while enhancing process sustainability. In this study, the evolution of the bacterial ecosystem of fresh salmon fillets was investigated under two superchilling temperatures (–1.8 °C and –2.8 °C) and compared with conventional refrigeration at 2 °C and storage at the initial freezing point (–0.8 °C). Total viable counts were monitored over a 20-day storage period using Plate Count Agar (PCA), and bacterial community diversity was assessed at day 0 and after 20 days of storage using 16S rRNA gene metabarcoding. Although superchilling did not fully inhibit bacterial growth, it effectively slowed microbial proliferation compared with refrigeration, thereby significantly extending microbiological shelf life. Bacterial community composition changed markedly after 20 days of cold storage, with subzero storage temperatures being more strongly associated with reduced microbial diversity. Pseudomonas became dominant under all conditions, particularly under superchilling (reaching up to 90.6%), followed by Photobacterium, which declined to the second position, and Brochothrix which was not detected at day 0. Cold temperatures strongly influenced microbial ecosystems, with superchilling promoting the development of more homogeneous communities. Overall, this study demonstrates the decisive influence of storage temperature on microbial community composition and provides a basis for selecting complementary approaches to optimize the industrial application of superchilling
From leaf to barrier scale: A multisource data evaluation of a spontaneous vegetative barrier to prevent potentially toxic element dispersal
No full textInternational audiencePotentially toxic elements (PTEs) may threaten both environmental and human health due to their persistence and their potential for widespread dispersal through wind and water erosion. Phytoremediation is often evaluated for soil contamination management although vegetation barriers have been less explored to reduce airborne dispersal of PTEs. The current study presents an approach to evaluate trapping capacity of woody species in vegetative barriers by combining field, laboratory measurements and airborne LiDAR point cloud to change scale from a single leaf to the entire vegetative barrier. To upscale leaf PTE concentration to plant and whole barrier estimation, allometric equations were used to evaluate accuracy of LiDAR HD above-ground volume estimation. This approach was tested on a spontaneous vegetative barrier surrounding PTE contaminated brownfields in Marseille (France). Although dense and overlapping shrub and tree canopies made measurements challenging, strong correlations were found between both methods (R 2 = 0.93 and 0.82 for Pinus halepensis and Pistacia lentiscus, respectively). Although PTE concentrations (As, Cd, Cu, Pb, Sb, Zn) in leaves were relatively low compared to those in soils (203 to 6592 times lower), the fraction attributed to atmospheric deposition represented a significant portion of leaf contamination, accounting for 22 % of total Pb and 44 % of total Sb. Similar efficiencies in trapping PTEs were observed between P. halepensis and P. lentiscus. The vegetative barrier, as a whole, can be considered as efficient to restrict contaminated particle dispersal in the studied context. This study underscores the accuracy of combining diverse data sources for robust assessment of nature-based solutions to mitigate contamination, moving beyond leaf-level trapping to a comprehensive barrier-scale evaluation
The evolving landscape of farmland ownership in Europe: implications for food system sustainability
No full textInternational audienceThis study examines the evolving dynamics of farmland ownership in Europe, focusing on the implications of ownership changes, foreign direct investments (FDI), and land concentration on the sustainability and resilience of European food systems. A scoping review of academic literature, available data sources, and policy documents revealed a knowledge gap regarding the evolution of European farmland ownership and its sustainability impacts. To address this, a pan-European geospatial statistical analysis was conducted, identifying ownership patterns, temporal changes and related economic performance. Subsequently, the statistical analysis provides a foundation to assess how ownership transformations affect food system sustainability and resilience. Findings show that in 2020, family farms were the dominant landowners across Europe. However, between 2016 and 2020, a shift toward company-owned farms occurred, particularly in Central and Eastern Europe. Drawing on global research on land acquisitions and sustainable agriculture, the study underscores that while companyowned farms may offer economic efficiencies, family farm ownership is vital for food security and local control over land and production. The study calls for continued monitoring of ownership trends and deeper investigation into their benefits, risks, and consequences. It recommends policy measures that balance investment incentives in the European food system with protections for local communities, that promote transparency in land transactions, and safeguard the long-term sustainability of European agriculture by upholding labor and environmental standards
How to integrate biology, physics and chemistry for a better description of soil water dynamics?
No full textInternational audienceNumerous and diverse edaphic organisms have the capacity to modify several physical and chemical soil characteristics that influence water transfers. Considering these modifications in modeling approaches would make for more accurate descriptions and modeling of water fluxes in soils. Some impacts of biological activity on soil physical aspects (e.g. modification of the pore space) have been described for 5-10 years now, and are being increasingly accounted for in water transfer models.However, the situation is not the same for biologically-driven chemical modifications linked to the secretion of organic molecules by soil organisms: modeling their consequences on pore space chemical properties and water transfers has just started. We here shortly survey prominent effects of biological activity on water-transfer related soil properties, and describe their coupling with existing water transfer models. We then propose possible ways for a better integration of biological soil modifications into such models. Among these, we point out that an energy-based theoretical framework would not only be consistent with the basic principles of thermodynamics, but would also foster synergies between ecologists, physicists and chemists, to better describe and predict water dynamics in soils and interactions with the soil biota. This would pave the way to model the evolution, on the scale of a few decades, of the water flow regulation services provided by soils</p
Optimizing the Viability of Interacting Systems with Evolutionary Algorithms
No full textInternational audienceViability theory studies the behavior of dynamical systems, with the aim of keeping them viable, or in other terms, keep their trajectories within desired constraints in the state space. Finding strategies to keep a dynamical system viable is already a challenge for optimization algorithms, but this task becomes even harder for multi-agent systems, where agents’ individual decision can influence the dynamics of the whole system. In this paper, we consider a multi-agent dynamic system and introduce an evolutionary approach for optimizing agents’ interaction behaviour, delimited by some a priori agreements, in the form of a set of commitments, with the objective of keeping the system viable. This approach is tested on the case-study of a collective project grouping several agritouristic activities on a shared place. Experimental results show that it is possible to find a set of agents’ commitments that can maintain system viability, supporting the proposed framework’s effectiveness
Instabilités mécaniques et claquage pour les tiges hélicoidales en présence de perversion
No full textInternational audienceEquilibrium configurations of helical elastic rods during quasi-static unwinding are studied experimentally and theoretically. At a critical degree of unwinding, the helical conformation destabilizes into a mixed phase consisting of two helices with opposite chiralities connected by a perversion. As unwinding progresses, the perversion migrates along the rod, eventually disappearing, leading to a pure helical conformation with opposite chirality from the initial state. Measurements of axial torque and force as functions of extension and winding reveal remarkable phenomena: (i) As the perversion migrates, the torque remains nearly constant. (ii) The transition from a pure helix to a configuration with perversion is accompanied by snapping events, seen as singularities in torque and force. (iii) At a critical force, the perversion destabilizes and transitions to a self-touching conformation. The phase diagram and overall mechanical behavior are reproduced using a biphasic model. A shooting technique, numerical path-following methods and finite element simulations are employed to assess the instability of the perversion and the associated snapping toward self-contact. The singularity at the creation of the perversion is reproduced by incorporating clamping effects within path-following methods. An analogy with first-order phase transitions is discussed. The nearly constant torque in the mixed phase is reminiscent of a Maxwell plateau, while the creation of a perversion with snapping corresponds to a nucleation event. Finally, to apply our analysis to plant tendrils, we study a specific line in the phase diagram of the mixed state corresponding to zero net turns. The associated transition is continuous and supercritical.Les configurations d'équilibre des tiges élastiques hélicoïdales lors de leur déroulement quasi-statique sont étudiées expérimentalement et théoriquement. À un degré critique de déroulement, la conformation hélicoïdale se déstabilise pour former une phase mixte constituée de deux hélices de chiralités opposées reliées par une perversion. À mesure que le déroulement se poursuit, la perversion migre le long de la tige, pour finalement disparaître, aboutissant à une conformation hélicoïdale pure de chiralité opposée de l'état initial.Les mesures du couple axial et de la force en fonction de l'extension et du déroulement révèlent des phénomènes remarquables :(i) Pendant la migration de l'inversion, le couple reste presque constant.(ii) La transition d'une hélice pure à une configuration avec inversion s'accompagne de phénomènes de rupture brusque, observés comme des singularités dans les mesures de couple et de force.(iii) À une force critique, la perversion se déstabilise pour adopter une conformation avec auto-contact.Le diagramme de phase et le comportement mécanique global sont reproduits à l'aide d'un modèle biphasique. Une technique de tir ("shooting"), des méthodes numériques de suivi de chemin et des simulations par éléments finis sont utilisées pour analyser l'instabilité de la perversion et les phénomènes claquage associés menant à l'auto-contact. La singularité à la création de la perversion est reproduite en incluant les effets de fixation dans les méthodes de suivi de chemin.Une analogie avec les transitions de phase du premier ordre est discutée. Le couple presque constant dans la phase mixte rappelle un plateau de Maxwell, tandis que la création d'une perversion accompagnée d'un claquage correspond à un événement de nucléation. Enfin, pour appliquer cette analyse aux vrilles de plantes, une ligne spécifique dans le diagramme de phase de l'état mixte correspondant à un nombre net de tours nul est étudiée. La transition associée est continue et supercritique
Toward sustainable transformer oil recycling: comparative efficacy of adsorbents and CFD simulation analysis
No full textInternational audienceTransformer insulating oils undergo progressive degradation due to oxidation, accumulation of aging by-products, and contamination by metallic particles. Proper regeneration of these oils is crucial to extend transformer lifespan and reduce environmental impact. This study investigates the performance of locally activated Algerian adsorbents (Illite and Maghnite) compared to commercial adsorbents (activated Bauxite and Sepiolite) for the regeneration of degraded transformer oils. The materials were evaluated for their adsorption efficiency toward acids, water, and oxidation products, as well as their ability to restore key electrical and thermalproperties. Activated Illite and Maghnite demonstrated performance comparable to commercial adsorbents, significantly reducing the acid number from 0.23 to 0.01 mg KOH/g. Illite exhibited superior reusability, maintaining regeneration efficiency over 300 cycles. Additionally, sulfur compounds were reduced from 344 to 40 ppm. Treated oils achieved a breakdown voltage of 78 kV and a dielectric dissipation factor of 0.995, closely matching new oil standards. Computational fluid dynamics (CFD) simulations were employed to assess Illite’s behavior in industrial-scale oil treatment, supporting its effectiveness as a substitute for Bauxite. The results highlight Illite’s potential as a viable, sustainable, and locally available alternative for transformer oil recycling. Nevertheless, challenges related to large-scale implementation, including material availability, cost, and process integration, remain and warrant further investigation. This study contributes to the development of environmentally responsible and economically competitive solutions for the regeneration of insulating oils using natural adsorbents.Les huiles isolantes des transformateurs subissent une dégradation progressive due à l'oxydation, à l'accumulation de sous-produits de vieillissement et à la contamination par des particules métalliques. Une régénération adéquate de ces huiles est essentielle pour prolonger la durée de vie des transformateurs et réduire leur impact sur l'environnement. Cette étude examine les performances d'adsorbants algériens activés localement (illite et maghnite) par rapport à des adsorbants commerciaux (bauxite activée et sépiolite) pour la régénération d'huiles de transformateur dégradées. Les matériaux ont été évalués en fonction de leur efficacité d'adsorption des acides, de l'eau et des produits d'oxydation, ainsi que de leur capacité à restaurer les propriétés électriques et thermiques essentielles. L'illite et la maghnite activées ont démontré des performances comparables à celles des adsorbants commerciaux, réduisant considérablement l'indice d'acide de 0,23 à 0,01 mg KOH/g. L'illite a montré une réutilisabilité supérieure, conservant son efficacité de régénération pendant plus de 300 cycles. De plus, les composés soufrés ont été réduits de 344 à 40 ppm. Les huiles traitées ont atteint une tension de claquage de 78 kV et un facteur de dissipation diélectrique de 0,995, ce qui correspond étroitement aux nouvelles normes applicables aux huiles. Des simulations de dynamique des fluides computationnelle (CFD) ont été utilisées pour évaluer le comportement de l'illite dans le traitement du pétrole à l'échelle industrielle, confirmant son efficacité en tant que substitut à la bauxite. Les résultats soulignent le potentiel de l'illite en tant qu'alternative viable, durable et disponible localement pour le recyclage des huiles de transformateur. Néanmoins, les défis liés à la mise en œuvre à grande échelle, notamment la disponibilité des matériaux, le coût et l'intégration des processus, demeurent et méritent d'être approfondis. Cette étude contribue au développement de solutions respectueuses de l'environnement et économiquement compétitives pour la régénération des huiles isolantes à l'aide d'adsorbants naturels
The industrial cost of fixed exchange rate regimes
No full textInternational audiencePremature deindustrialization in most emerging and developing economies is one of the most striking stylized facts of the recent decades. In this paper, we provide solid empirical evidence supporting that the choice of a fixed exchange rate regime accelerates this phenomenon. Relying on a panel of 146 developed, emerging, and developing countries over the 1974–2019 period, we show that fixed exchange rate regimes have had a negative, significant, and robust effect on the size of the manufacturing sector—developing countries being the most affected by the industrial cost of such a regime. Additional gravity model regressions show that the impact of fixed regimes passes through the trade channel. In particular, this regime has kept countries with low relative productivity in a state of structural dependence on imports of manufactured products to the detriment of the emergence of a strong local manufacturing sector
Simultaneous joint inversion of synthetic seismic and ground penetrating radar data with petrophysical variable change
No full textInternational audienceIn this work, we address the characterization of porosity and water saturation in a synthetic model of a shallow alluvial subsurface using frequency electromagnetic and seismic data. The inversion method employs a Gauss–Newton scheme, where the Jacobian of the merged seismic and electromagnetic data is formulated with respect to the spatially heterogeneous petrophysical parameters. This is made possible by introducing realistic petrophysical relationships, which significantly reduce the number of unknowns in the inverse problem and incorporate a strong prior correlation between the information contained in both data types regarding the subsurface composition. The results obtained show that this simultaneous joint petrophysical inversion produces reconstructions with clear improvements compared to independent petrophysical inversion. Indeed, it greatly enhances the spatial resolution of subsurface mapping, as well as the quantitative estimation of porosity and saturation
Induction of human cytochrome P450 enzyme activities by metabolism disrupting chemicals in the hepatic cell line HepaRG
No full textInternational audienceMetabolism disrupting chemicals (MDCs) are a class of endocrine disrupting substances that promote metabolic changes leading to metabolic disorders in humans. Central to assessing their adverse effects is the need to better understand their modes of action (MoA). Cytochrome P450 (CYP) enzymes play a major role in xenobiotic metabolism, but also catalyse many endogenous metabolic reactions. Therefore, modulation of CYP functionality may impact homeostasis, contributing to adverse outcomes. At the functional level, alteration of the activity of human CYPs J o u r n a l P r e -p r o o f by MDCs largely remains unexplored. In this study we investigated the capability of six candidate MDCs, bisphenol A (BPA), perfluorooctanoic acid (PFOA), tributyltin (TBT), dichlorodiphenyldichloroethylene (p,p'-DDE), triclosan (TCS) and triphenylphosphate (TPP) to induce CYP1A2, CYP2B6 and CYP3A4 activities in the human hepatic HepaRG cell line. The CYP induction test method previously validated for pharmaceuticals was optimised and selected MDCs were tested in the context of the European Horizon 2020 GOLIATH project. Induction was revealed using a cocktail of CYP-selective probe substrates, followed by probe metabolite quantification by mass spectrometry. All MDCs except TCS induced CYP activities. PFOA, TBT, p,p'-DDE and TPP induced CYP1A2, TPP being the most potent inducer. BPA, PFOA, TBT and TPP induced CYP2B6, PFOA being the most potent inducer. BPA, PFOA, TBT, p,p'-DDE and TPP all induced CYP3A4, p,p'-DDE and BPA being the most potent inducers. These results highlight the capability of candidate MDCs to induce key CYP activities in a human hepatic relevant model, paving the way for a better understanding of MDCs mechanisms of action