Portail HAL de l'Université du Littoral Côte d'Opale
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Les directeurs des compagnies et le Conseil de commerce au XVIIIe siècle
No full textInternational audienceLe Conseil de commerce est créé le 29 juin 1700 pour examiner toutes les propositions et mémoires qui lui seront envoyés. Il se maintiendra tout au long du siècle. Il réunit outre des ministres, des commissaires, des députés des villes… mais aussi des directeurs de compagnies. Dans quelle mesure ont-ils pu influer sur les débats au Conseil et protéger les intérêts des compagnies dont ils assurent la conduite
Set-Based Assumption-Guarantee Reasoning for Handling Uncertainty in Functionality and Safety Verification of Dynamic Systems
No full textInternational audienceThe increasing complexity of Cyber-Physical Systems (CPSs), particularly in safety-critical applications, necessitates advanced methods for design and verification. Modern CPSs must operate reliably in uncertain environments characterized by noise, external disturbances, and dynamic conditions. Addressing these challenges requires methodologies that are capable of capturing both internal system complexities and external uncertainties. Assumption-Guarantee reasoning, often expressed using temporal logics, provides a modular framework for verification. However, current temporal logics are limited in their ability to effectively handle uncertainties. This paper introduces Set-Based Temporal Logic (SBTL) as a solution to these limitations by extending traditional contract specifications to incorporate a set-based reachability analysis, which enables a more detailed representation of uncertainty and accommodates for implicit system behaviors. By integrating set-based reasoning with temporal constraints, SBTL offers a more expressive and robust specification formalism. The approach is demonstrated through simulations of a DC motor-based drive train operating in an uncertain and dynamic environment, featuring a combined state and disturbance estimator. Results highlight the enhanced robustness of the closed-loop control system, ensuring consistent disturbance reconstruction and alignment of system trajectories with desired behavior
Multiscale phytoplankton dynamics in a coastal system of the eastern English Channel: the Boulogne-sur-Mer coastal area
No full textInternational audienceTo study changes in phytoplankton community composition on different timescales, an automated flow cytometer (CytoSub, CytoBuoy b.v.) was deployed at the MAREL Carnot automated monitoring station in Boulogne-sur-Mer (eastern English Channel, France) during spring (2021 and 2022) and summer (2022), following an Eulerian approach. Phytoplankton dynamics were recorded every 2 h, distinguishing 11 phytoplankton functional groups (PFGs) based on optical and fluorescence properties. This enabled detailed characterization of PFG successions, including MicroRED (mostly diatoms) and NanoRED (mostly haptophytes of the species Phaeocystis globosa) transitions in spring, as well as a summer dominance by PicoORG (picocyanobacteria, mostly of the genus Synechococcus) and PicoRED. Four rare events, including a salinity drop (April 2021), strong winds (May 2021 and April 2022), and a marine heat wave (July 2022), caused rapid shifts in phytoplankton community assemblage. Empirical mode decomposition (EMD) and Lomb–Scargle periodogram (LSP) analyses revealed that 85±10 % of variability in total phytoplankton abundance, red fluorescence (a proxy of chlorophyll a), and Shannon diversity occurred on relatively short timescales (9 h to 11 d) for time series of several months, highlighting the value of high-frequency monitoring in capturing ecological dynamics under macrotidal conditions in the eastern English Channel
Price elasticity of housing supply in France: a multi-level estimation
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Identification des espèces de poissons et de leurs traits de vie à l'aide de leur otolithe
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Full-Resolution Sentinel-3 Satellite Observations of Phytoplankton Phenology in Optically Complex Waters of the Northern Patagonian Shelf
No full textInternational audienceIn this study, we characterized phytoplankton biomass variability in El Rincón, a shallow and biologically productive coastal region in the Patagonian Continental Shelf. We used as a proxy 7 years (2017-2024) of high-resolution Sentinel-3 OLCI satellite data to capture the fine scale spatio-temporal variability of Chl-a in this region. To obtain Chl-a concentration, we applied a regionally validated algorithm (MuRB&NDCI) which provides more accurate Chl-a estimates compared to traditional algorithms, particularly in optically complex waters. Self-organizing maps (SOM) neural network was applied to identify four distinct bio-geographical regions with unique bloom dynamics. The phenological estimates revealed that phytoplankton blooms typically initiate in fall (March), peak during winter (May-August), and are more pronounced near the Bahía Blanca Estuary (BBE), where nutrient and sediment inputs drive high productivity. The findings presented in this work highlight the utility of Optical Water Class-based algorithms for capturing the fine-scale spatiotemporal variability of Chl-a in coastal systems. This study advances our understanding of phytoplankton dynamics in El Rincón and underscores the importance of customized satellite-derived approaches for monitoring and managing productivity in shallow coastal environments
La Seconde Guerre mondiale à Ecques
No full textInternational audienceLa Seconde Guerre mondiale constitue un marqueur fort dans l’histoire du XXe siècle. À l’écart des principales zones de combat, les villages de l’Audomarois comme celui d’Ecques sont pourtant touchés, que ce soit par la présence de troupes françaises d’abord, allemandes ensuite pendant les quatre années de l’Occupation, par l’absence d’une partie des hommes retenus prisonniers et par les bombardements aériens détruisant des secteurs entiers de la commune
Gelatinous matrix, an original strategy to cope with oligotrophy in Nassellaria (Radiolaria)
No full textAbstract Radiolaria are heterotrophic protists abundant in the world’s oceans playing important roles in biogeochemical cycles. Some species host photosynthetic algae also contributing to primary production. Such mixotrophic behaviour is believed to explain their ecological success in oligotrophic waters, notably Collodaria, exclusively mixotrophic radiolarians within a gelatinous matrix. Yet, our understanding of Radiolaria ecology is limited to direct observations, as they have so far withstood reproduction in culture and their genomes are unexplored. Sampling oligotrophic California Current communities revealed an abundant, rarely observed population of Nassellaria of the genus Phlebarachnium , characterized to live within a gelatinous matrix along with other Radiolaria. Phylogenetic reconstruction of the ribosomal DNA suggests that these distantly related lineages within Nassellaria independently developed the ability to produce a gelatinous matrix ∼150 million years ago. By matching physical samples with their genetic signature, we identified these rarely observed organisms in global metabarcoding datasets, revealing strong biogeographic affinity to oligotrophic water masses. Global ocean co-occurrence networks showed that Radiolaria with a gelatinous matrix have a distinct biogeography compared to those without the matrix. Results suggest that the gelatinous matrix is an adaptation to oligotrophic waters, but further research is needed to evaluate similarities between the gelatinous matrices across different Radiolaria groups. This strategy could increase the effective volume to weight ratio favoring prey capture and create a favorable microenvironment for symbionts, enhancing ecological success in nutrient-depleted waters. This study advances our understanding of eukaryotic diversity evolution, emphasizing specific advantages of certain adaptations, specifically when evolution occurs independently across lineages
FermEndive ou comment essayer de valoriser les co-produits de la culture d'Endive de Haut-de-France pour améliorer la durabilité d'une filière fortement impactée par la crise
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Effects of nature-derived biostimulants on rhizosphere microbial biomass, diversity, and networks
No full textInternational audiencePlant biostimulants have gained increasing attention in agriculture as nature-derived solutionsdue to their beneficial effects on plant growth, physiology, and metabolism. However, theirinfluence on soil microbial communities remains poorly understood. In this study, weevaluated the effects of two biostimulants, one derived from marine algae fermentation withbenefical bacteria (Plantiful™) and another produced from medicinal plants fermented withbenefical bacteria (CelexT07™,) BioSun Inc.), on rhizosphere microbial communities, incomparison with NPK fertilization and a commercial seaweed extract (Phylgreen™). Toachieve this, we combined metabarcoding sequencing with phospholipid fatty acid (PLFA)profiling toassess microbial biomass and community structure.Our results showed no significant differences in microbial biomass among treatments. Bothbacterial and fungal communities were dominated by Actinobacteriota, Pseudomonadota,Acidobacteriota, Chloroflexota, and Ascomycota, with similar richness and Shannon diversityindices across treatmemnts. Functional analyses of fungal trophic guilds and metabolicprofiles revealed no detectable shifts in metabolite potential, substrate utilization, or gene-associated pathways. Microbial network analysis indicated that Plantiful™ and CelexT07™slightly increased network connectivity and competitive interactions, while maintaining abalanced proportion of positive and negative associations, as well as stable richness andmodule structures.Overall, our findings demonstrate that Plantiful™ and CelexT07™ are safe biostimulants thatdo not disrupt the composition, diversity, or functional potential of soil microbialcommunities