Portail HAL de l'Université du Littoral Côte d'Opale
Not a member yet
11255 research outputs found
Sort by
Bien prescrire de l’activité physique après un diagnostique d’insomnie chronique ? Essai randomisé contrôlé chez des femmes d’âge moyen
No full textInternational audienceObjectif:Depuis 2016, l'activité physique adaptée (APA) peut être prescrite par les médecins et dispensée dans le réseau des 500 maisons Sport Santé labellisées par l'état. Un nombre croissant d'études montre que l'APA est une intervention viable pour aider à traiter l'insomnie chronique (IC). Or, les mécanismes physiologiques d'action des APA sur le sommeil doivent être mieux étudiés pour permettre des prescriptions précises et efficaces, que ce soit à la place ou en complément d'autres thérapies. Le but de cette étude était donc d'étudier l'effet d'un réentraînement d'intensité modérée et vigoureuse sur le sommeil et d'en déterminer les mécanismes dans le mais d'aider les médecins à bien prescrire les APA.Méthodes:Vingt-quatre femmes adultes observées en IC (critères DSM-5) dans deux centres du Réseau Morphée ont participé à notre étude. Elles ont été placées aléatoirement dans un groupe APA ou contrôle (GC). L'intervention consistait en 3 entraînements de 1 h 15 par semaine (50 min à 70 % de FC max et 25 min au-dessus de 80 % de FC max) pendant 12 semaines. Les mesures faites à T0 et T + 12 semaines concernaient des questionnaires sur l'indice de sévérité de l'insomnie (ISI), la somnolence (ESS), le stress (PSS10) et l'anxiété (HAD), des enregistrements actifs, une mesure de la température centrale (TC) de 30 h en continu, le cortisol capillaire et la variabilité de la fréquence cardiaque nocturne.Résultats:Seul le groupe APA a montré une significative de la santé cardiovasculaire, des scores ISI, ESS et PSS10, du WASO et une augmentation de 33 min du TST (ns). La batyphase était significativement abaissée et l'amplitude plus grande. L'analyse montre une corrélation significative entre le score ISI et l'évolution de la TC nocturne moyenne et les valeurs de batyphase.Conclusion:Les APA sont donc efficaces pour le sommeil, la santé mentale et physique des femmes déterminées en IC. Le choix d'une APA devrait viser à augmenter nettement la température centrale pendant la pratique afin d'induire des adaptations de thermorégulation favorisant le sommeil et le rebond de l'activité du système nerveux. L'inclusion des APA dans les ETP devrait désormais être prise en charge exclusivement
Equations d'Hamilton à délais pour les Configurations Centrales
No full textInternational audienceWe provide in this paper the hamiltonian delay equations of motion for the newtonian n-body problem deduced from the quantum calculus of variations developed in Cresson 2005; Cresson, Frederico, and Torres 2009; Ryckelynck and Smoch 2013, 2014. These equations are brought into the usual lagrangian and hamiltonian formulations of the dynamics and yield sampled functional equations involving generalized derivatives. We investigate especially homographic solutions to these equations that we obtain by solving algebraic systems of equations similar to the classical ones. When the potential forces are homogeneous, homographic solutions to the delayed and to the classical equations may be related through an explicit expansion factor that we provide. Consequently, perturbative equations both in lagrangian and hamiltonian formalisms are deduced
Assessment of turbulent dispersion in the Red River plume region, northeast Vietnam, based on Lagrangian observations and modeling
No full textInternational audienceThe study aims to assess turbulent dispersion processes in the coastal regions of northeastern Vietnam, in order to meet the major challenge of monitoring the fate of particulate materials in this part of the East Vietnam Sea, home to the most famous tourist sites and economic sites. The study area is strongly influenced by the freshwater discharge of the Red River, which creates a large river plume, greatly affecting coastal circulation and turbulent dispersion. The monsoon wind profoundly alters the dynamics of the river plume, pushing light surface water seaward over long distances, in summer, and toward the coast, in winter. Sea surveys were organized for the first time in this region in 2022 and 2023 to better characterize the processes controlling coastal flow variability and turbulent dispersion in the plume region and surrounding waters. Surface drifters, released in the plume region, were tracked during short periods of time, lfrom one to a few days. Current velocity profiling and CTD profiling have been also done. Estimates of the relative dispersion based on surface drifter measurements have revealed that the dispersion regime is local, mainly ballistic and Richardson, induced by turbulent eddies whose size does not exceed a few km. Local wind variability, combined with variations in bathymetry, considerably affects the transport pathways of real drifters and modifies the dispersion regime. A coastal circulation model was used to better assess dispersion processes over the entire study area and for a wide range of variability in the main forcing terms. Virtual surface drifters were tracked in the model velocity field during the surveying periods. The results revealed that, on scale of several days, the transport of passive tracers is considerably affected by irregularities in current velocity fields associated with zones of current convergence and divergence. The results also demonstrated that merging observations with model outputs significantly improves the representation of small scale features of current variability, turbulent mixing, and horizontal stirring of tracers in the plume region
César était-il généreux avec les Juifs ? Retour sur quelques documents cités par Flavius Josèphe (AJ XIV, 190-210)
No full textInternational audienc
Optimizing Ni°-exoluted phyllosilicate catalysts for the CO2 methanation reaction
No full textInternational audienc
La mutabilité internationale des concepts et paradigmes dans le champ des sciences sociales du sport, des loisirs et de la récréation
No full textInternational audienceWhen we look at scientific production in the sociology of sport, leisure and recreation on an international scale, we see a significant presence of Anglo-Saxon references in Francophone literature and, conversely, a fairly significant presence of certain Francophone references (i.e. French Theory) in Anglo-Saxon literature. However, a closer look at these mobilizations reveals the mutability of these concepts and paradigms. As the Italian locution "Traduttore, traditore" suggests, there is an irreducible difference between a text and its possible translations. De facto, the mobilization by Anglo-Saxon authors of Francophone references (i.e. Foucault, Derrida, Deleuze, Barthes, Beauvoir, etc.) or, a contrario, the Anglo-Saxon references mobilized by Francophone authors (i.e. Mead, Butler, Stebbins, etc.) testify to readings that are sometimes surprising, or at least challenging for native speakers or bilinguals. We will examine the issue of re-reading and mutability in the apprehension of theoretical models, i.e., the capacity to generate changes and modify regimes of understanding and mobilization by displacing them in new social and cultural contexts.Lorsque l’on regarde la production scientifique en sociologie du sport, des loisirs et de la récréation à l’échelle internationale, on observe une prégnance importante des références anglosaxonnes dans la littérature francophone et, inversement, une présence assez importante de certaines références francophones (i.e. la French Theory) dans la littérature anglosaxonne. Pourtant, en regardant de plus près ces mobilisations, nous pouvons mettre en exergue une mutabilité de ces concepts et paradigmes. Comme le suggère la locution italienne, « Traduttore, traditore », il y a une différence irréductible entre un texte et ses traductions possibles. De facto, les mobilisations qui sont faites par les auteurs anglo-saxons de références francophones (i.e. Foucault, Derrida, Deleuze, Barthes, Beauvoir, etc.) ou, a contrario, les références anglosaxonnes mobilisées par les auteurs francophones (i.e. Mead, Butler, Stebbins, etc.) témoignent de lectures parfois surprenantes, du moins qui interpellent les natifs ou bilingues. Sera interrogé cet enjeu de la re-lecture et de la mutabilité dans l’appréhension des modèles théoriques, à savoir une capacité à générer des changements et à modifier des régimes de compréhension et de mobilisation en les déplaçant dans de nouveaux contextes sociaux et culturels
Overview of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) Field Experiment
No full textInternational audienceThe Alaskan Layered Pollution And Chemical Analysis (ALPACA) field experiment was a collaborative study designed to improve understanding of pollution sources and chemical processes during winter (cold climate and low-photochemical activity), to investigate indoor pollution, and to study dispersion of pollution as affected by frequent temperature inversions. A number of the research goals were motivated by questions raised by residents of Fairbanks, Alaska, where the study was held. This paper describes the measurement strategies and the conditions encountered during the January and February 2022 field experiment, and reports early examples of how the measurements addressed research goals, particularly those of interest to the residents. Outdoor air measurements showed high concentrations of particulate matter and pollutant gases including volatile organic carbon species. During pollution events, low winds and extremely stable atmospheric conditions trapped pollution below 73 m, an extremely shallow vertical scale. Tethered-balloon-based measurements intercepted plumes aloft, which were associated with power plant point sources through transport modeling. Because cold climate residents spend much of their time indoors, the study included an indoor air quality component, where measurements were made inside and outside a house to study infiltration and indoor sources. In the absence of indoor activities such as cooking and/or heating with a pellet stove, indoor particulate matter concentrations were lower than outdoors; however, cooking and pellet stove burns often caused higher indoor particulate matter concentrations than outdoors. The mass-normalized particulate matter oxidative potential, a health-relevant property measured here by the reactivity with dithiothreiol, of indoor particles varied by source, with cooking particles having less oxidative potential per mass than pellet stove particles
Mycorrhiza-induced resistance in wheat leaves and protection against pathogenic fungi
No full textInternational audienceMore than 80% of land plants can form symbiotic relationships with arbuscular mycorrhizal fungi (AMF), including crops. By associating with plant roots, these beneficial fungi increase the volume of soil exploration, which generally results in better mineral and water nutrition of plants. They are known to improve plant tolerance to abiotic stress, and researches in the last decades have shown that AMF can also induce local or systemic plant resistance to pathogens, which is known as mycorrhiza-induced resistance (MIR).Inoculation of bread wheat roots with a CMA, Funneliformis mosseae, provides protection in controlled conditions against powdery mildew and septoria tritici blotch, two fungal diseases that affect the leaves of wheat plants. This protection is partial and related to the induction of MIR in wheat leaves, in various cultivars. In mycorrhizal plants, the expression profile of some defense-related genes in leaves was modulated before any challenge by the pathogen, suggesting a systemic elicitation of some genes rather than a strict priming of plant defense. Among them, genes encoding PR-proteins, proteins involved in flavonoid and polyamine synthesis were up-regulated. In the early stages after inoculation with Blumeria graminis f.sp. tritici, responsible for powdery mildew, the jasmonate and pipecolic pathways were stimulated. Microscopic analyses highlighted an increase in phenolic compounds accumulation in leaves at the penetration site of the fungus. The induction of defenses and the link between growth and defense will be discussed