Portail HAL de l'Université du Littoral Côte d'Opale
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Croisière et politiques littorales : les changements climatiques à la barre ?
No full textInternational audienc
Phytomanagement of a trace element-contaminated agricultural soil using aromatic and medicinal plants to produce essential oils
No full textInternational audienceTo cope with the soil trace element (TE) pollution, phytomanagement was brought forward as an eco-friendly and feasible approach.To meet the dual requirements of environmental and economic performances, phytotechnologies are now combined with the valorisarionof biomass produced on polluted soils. Among the eco-innovative channels intended for the non-food valorisation of the producedbiomass, the cultivation of aromatic and medicinal plants producing essential oils (EO), high-added value biosourced products, hasbeen suggested within the framework of PhytEO and DEPHYTOP projects, funded by ADEME. Thus, this work contributed to evaluatethe relevance of a management approach based on clary sage, angelica and coriander cultivation, combined or not with a mycorrhizalinoculum, on in situ experimental plots polluted or not with TE. Both clary sage, angelica and coriander have shown a good ability tosettle in, to grow and to produce high amounts of biomass, despite the presence of high TE concentrations in the soil. The addition of anamendment based on arbuscular mycorrhizal fungi enhanced the mycorrhizal colonisation rates of both coriander and clary sage roots.However, no significant improvement was observed in terms of plants’ growth, EO amounts and quality. Moreover, mycorrhizal inoculationallowed TE immobilisation in soils, in particular Pb, and reduced TE (Cd and Pb) transfers in aerial parts of clary sage. Besides, theEO distilled from clary sage inflorescences, angelica seeds and coriander (aerial parts or seeds) grown on TE polluted soils, displayeda highly satisfactory quality, regarding the absence of contamination by TE or pesticide residues (trace amounts). Their chemical compositionswere not altered by both TE pollution and mycorrhizal inoculation and were characterized by several active principles, suchas linalool, linalyl acetate, germacrene, a-pinene, g-terpinene, 2-decenal, decanal and 2-dodecenal. Furthermore, several biologicalproperties with potential applications in non-food fields such as crop protection (antifungal, antigerminative and herbicidal) or humanhealthcare (antioxidant and anti-inflammatory) have been brought forward. However, despite its ability to form inclusion complexes withEO components, β-cyclodextrin has shown no significant improvement of the tested EO biological activities. On another note, the soilrevegetation with clary sage displayed a clear shaping of the bacterial and fungal communities, in both the rhizospheric soil and theroots of the aromatic plant species. Altogether, our results combined with the techno-economic feasibility assessment of the channel“aromatic and medicinal plants/EO” have emphasised clary sage as a good candidate for the phytomanagement of TE-polluted soils
New examples of words for which the binomial complexities and the subword complexity coincide
No full textThe complexity of an infinite word can be measured in several ways, the twomost common measures being the subword complexity and the abelian complexity. In2015, Rigo and Salimov introduced a family of intermediate complexities indexed byk ∈ N>0: the k-binomial complexities. These complexities scale up from the abeliancomplexity, with which the 1-binomial complexity coincides, to the subword complexity, to which they converge pointwise as k tends to ∞. In this article, we providefour classes of d-ary infinite words – namely, d-ary 1-balanced words, words with subword complexity n ∈ N>0 7→ n + (d − 1) (which form a subclass of quasi-Sturmianwords), hypercubic billiard words, and words obtained by coloring a Sturmian wordwith another Sturmian word – for which this scale “collapses”, that is, for which allk-binomial complexities, for k ≥ 2, coincide with the subword complexity. This workgeneralizes a result of Rigo and Salimov, established in their seminal 2015 paper,which asserts that the k-binomial complexity of any Sturmian word coincides with itssubword complexity whenever k ≥ 2
Moerdijk Hopf algebras of decorated rooted forests: an operated algebra approach
No full textIn this paper, we first endow the space of decorated planar rooted forests with a coproduct that equips it with the structure of a bialgebra and further a Moerdijk Hopf algebra. We also present a combinatorial description of this coproduct, and further give an explicit formulation of its dual coproducts through the newly defined notion of forest-representable matrices. By viewing the Moerdijk Hopf algebra within the framework of operated algebras, we introduce the notion of a multiple cocycle Hopf algebra, incorporating a symmetric Hochschild 1-cocycle condition. We then show that the antipode of this Hopf algebra is a Rota-Baxter operator on Moerdijk Hopf algebras. Furthermore, we investigate the universal properties of cocycle Hopf algebras. As an application, we construct the initial object in the category of free cocycle Hopf algebras on undecorated planar rooted forests, which coincides with the well-known Moerdijk Hopf algebra
Le numérique dans les sports de nature : étude exploratoire et inductive pour une première catégorisation des formes d’utilisation des outils connectés
No full textInternational audienceThis study is based on 73 interviews concerning the use of digital technology in outdoor sports. The analysis uses a mixed method incorporating a multiple correspondence analysis, a hierarchical classification, and an approach based on the “personas” method. Ten typical uses of digital technology characterized by eight synthetic variables were identified. The modeling of digital practices in outdoor sports highlights the similarities and differences between typical uses, also based on sporting characteristics.Cette étude s’appuie sur 73 entretiens concernant l’utilisation du numérique dans le cadre de la pratique des loisirs sportifs de nature. L’analyse mobilise une méthode hybride intégrant une analyse des correspondances multiples, une classification hiérarchique et une approche par la méthode des « personas ». Dix utilisations types du numérique caractérisées par huit variables synthétiques sont identifiées. La modélisation des pratiques connectées dans les sports de nature met en évidence les logiques de ressemblances et de différenciation entre les utilisations types, aussi sur base de caractéristiques sportives
Pierre Toufaire: career in Rochefort and history of construction in arsenals in the 18th century.
No full textInternational audiencePierre Toufaire, ingénieur de la Marine à Rochefort, offre l'exemple du parcours d'un "ingénieur des Bâtiments civils", ce groupe longtemps restés dans l'ombre des ingénieurs-constructeurs de la Marine. Or, ces professionnels ont beaucoup à dire sur le métier d'ingénieur à l'époque moderne, et l'intégration des savoirs nouveaux produits par les Lumières techniciennes au sein des arsenaux
Defense responses related to mycorrhizal-induced resistance in wheat against Zymoseptoria tritici
No full textInternational audienceArbuscular mycorrhizal fungi (AMFs) are considered promising biocontrol agents that can provide protection to plants against bio-aggressors through the triggering of mycorrhiza-induced resistance (MIR). Here, the protective systemic effect of the AMF species Funneliformis mosseae was evaluated in a susceptible wheat cultivar against Septoria tritici blotch (STB), caused by the hemibiotrophic ascomycete Zymoseptoria tritici. Mycorrhizal inoculation led to a root colonization rate of 42 % in 50-day-old wheat plants, associated with an overexpression of genes encoding nutrient transporters in roots and the accumulation of blumenol derivatives in roots and leaves, attesting to a functional mycorrhizal symbiosis. Concomitantly, mycorrhizal wheat plants exhibited a foliar protection rate of 78 % against Z. tritici. An up-regulation of two defense-related genes (PR1 and POX) in wheat leaves was also revealed consecutively to the AMF symbiosis establishment and prior to pathogen attack. These two genes and five other genes (PR5, PAL, GST, CalS, and CAD) were also up-regulated in leaves infected by Z. tritici alone during its biotrophic stage, whereas six genes (PR1, PR4, PR5, PAL, POX, and CalS) were up-regulated in mycorrhizal and Z. tritici-inoculated plants. Less accumulation of tryptophan and methylpipecolic acid was observed in infected leaves of mycorrhizal plants, indicating a stress alleviation in mycorrhizal wheat plants under Z. tritici attack. Our findings highlight the ability of F. mosseae to activate MIR and to protect wheat against Z. tritici by specifically remodeling gene expression in leaves
Effets de l'accessibilité aux emplois sur le chômage des quartiers
No full textNous cherchons à déterminer l’effet d’une meilleure accessibilité aux emplois sur le niveau de chômage d’un quartier. Nous combinons une approche théorique, via l’élaboration d’un modèle urbain, et une approche empirique, via l’estimation d’un modèle spatial (SEM) sur les régions de l’Île-de-France et des Hauts-de-France.Le modèle théorique introduit un mécanisme de création et de localisation du chômage original dans un modèle urbain plus classique. Il permet de reproduire une organisation de la ville globalement assez proche de celle des unités urbaines françaises et d’identifier deux mécanismes rendant compte de la localisation du chômage. Premièrement, une bonne accessibilité aux emplois, représenté par de faibles coûts de transport, peut s’accompagner d’un chômage élevé, car le quartier est attractif pour des individus menant une recherche active d’emploi. Deuxièmement, si le niveau de tension du marché de l’emploi est faible, c’est-à-dire que le nombre d’emplois accessibles et grands devant le nombre d’actifs pouvant y accéder, le chômage sera faible.La partie empirique mesure l’accessibilité aux emplois ainsi que le niveau de tension du marché de l’emploi depuis l’ensemble des IRIS des régions Île-de-France et Hauts-de-France, sous la forme d’indicateurs d’accessibilités gravitaires. Ces indicateurs sont utilisés dans un modèle économétrique incluant une dépendance spatiale du terme d’erreur (SEM), complété d’un ensemble de variables de contrôle (numéro du département, structure du parc de logement, accessibilité aux équipements et services). Il en ressort que l’accessibilité aux emplois et le niveau de tension du marché de l’emploi ont l’effet attendu. Le premier s’accompagne d’un plus haut taux de chômage, signe d’une plus grande attractivité de ces IRIS pour les demandeurs d’emplois. Le deuxièmes’accompagne d’un taux de chômage plus bas, car le nombre d’emplois accessibles par actifs pouvant les occuper est plus élevé.Ces résultats relativisent le pouvoir explicatif de l’accessibilité physique aux emplois sur le taux de chômage d’un quartier. Une bonne accessibilité physique aux emplois peut s’accompagner d’un niveau de chômage élevé du fait de l’attractivité du quartier. Mais à l’échelle de la ville, le niveau de tension du marché de l’emploi aura baissé et conséquemment, le chômage aussi.Il est important de souligner les limites de notre démarche, menéeà un instant donné. Des résultats plus robustes pourraient être obtenus en disposant des mêmes sources de données sur plusieurs années, idéalement sur un territoire ayant connu une modification conséquente de son réseau de transport. Nous ne disposions malheureusement pas de ces données
An ecosystem model for assessing potential impacts of offshore windfarm on Eastern English Channel ecosystem
No full textInternational audienceThe development of offshore windfarms (OWF) is crucial for the energy transition to achieve decarbonisation targets. However, the ecological effects of this expansion remain largely unexplored. This study use the OSMOSE model to investigate the potential impacts of OWF in the Eastern English Channel (EEC) ecosystem. The primary objective is to 1) improve the assessment of OWF effects on ecosystems by integrating multiple pressures within a single modelling framework, and 2) analyse ecosystem responses under various OWF deployment and fishing restriction scenarios.The OSMOSE model is a multispecies, individual-based model that relies on opportunistic predation. It was calibrated to reproduce observed trends of biomass, catch, and catch at length in the study area from 2002-2022. The model's emergent properties (e.g., growth, food web structure) were validated to ensure ecological realism.A factorial plan of simulations, incorporating OWF deployment and fishing restriction scenarios, provides ecosystem projections up to 2050. The OWF deployment scenarios include: 1) cost minimization, 2) exclusion from regulatory environmental protection zones, 3) long distance from the coast, and 4) a balanced scenario that combines elements from the previous three. The fishing restriction scenarios include: 1) no fishing closure, 2) closure for trawlers, and 3) closure for all fishing fleets. To represent potential OWF impacts, the simulations considered fishing restrictions during the operational phase and the following factors during the construction phase: fishing access restrictions, underwater noise, and sediment resuspension. Biomass, yield, and size-dependent indicators were analysed in a spatially and temporally explicit manner to provide insights into the OWF impact on different aspects of the EEC ecosystem.At the scale of the entire study area, we observed a slight influence of OWF on total biomass and total catch. However, size-based indicators showed an increasing trend under certain scenarios, suggesting a potential reserve effect. At the individual OWF scale, the response of these indicators varied across different areas. This study highlights the importance of considering both the specific deployment sites and fishing regulations in cumulative impact assessments of OWF
ON THE CRITICAL LENGTHS AND CONTROLLABILITY OF THE KAWAHARA EQUATION
No full textThis paper deals with the exact controllability of the Kawahara equation posed on a finite interval with one boundary control. We prove that the local exact controllability of Kawahara equation holds provided that the length of the interval does not belong to a countable set of critical lengths