Portail HAL de l'Université du Littoral Côte d'Opale
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Fusion des données de dérive lagrangienne et de sorties de modèles numériques pour une meilleure évaluation de la dispersion turbulente
No full textInternational audienceTransport and dispersion processes in the ocean are crucial, as they determine the lifetime and fate of biological and chemical quantities drifting with ocean currents. Due to the complexity of the coastal ocean environment, numerical circulation models have difficulties to accurately simulate highly turbulent flows and dispersion processes, especially in highly energetic tidal basins such as the eastern English Channel. A method of improving the results of coastal circulation modeling and tracer dispersion in the Dover Strait is proposed. Surface current velocities derived from Lagrangian drifter measurements in November 2020 and May 2021 were optimally interpolated in time and space to constrain a high-resolution coastal circulation MARS model, with careful attention given to selecting ensemble members composing the model covariance matrix. The space-time velocity covariances derived from model simulations were utilized by the optimal interpolation algorithm to determine the most likely evolution of the velocity field under constraints provided by Lagrangian observations and their error statistics. The accuracy of the velocity field reconstruction was evaluated at each time step. The results of the fusion of model outputs with surface drifter velocity measurements show a significant improvement (by ∼ 50 %) of the model capability to simulate the drift of passive tracers in the Dover Strait. Optimized velocity fields were used to quantify the absolute dispersion in the study area. The implications of these results are important, as they can be used to improve existing decision-making support tool or design new tools for monitoring the transport and dispersion in a coastal ocean environment
Fiscalità ed Epigrafia nel mondo romano. Nuove Ricerche
No full textInternational audienceThe proceedings of the conference that now come to light are intended as a continuation of the work that began five years ago: the 2019 conference in Catania - which saw, among others, the participation of scholars with great experience in the field of taxation and epigraphy - inaugurated, in fact, the meetings between experts on issues related to ancient taxation, considered, however, from a particular angle, that of epigraphy. If most of the papers presented at the first conference were devoted to the western provinces of the empire, with a focus on Africa, in this second one more space was reserved for the eastern provinces, which were the subject of interesting insights from various perspectives. The issues addressed and analysed with the help of methodologies or new approaches are sometimes very broad; on the other hand, some little-known dossiers have been opened up and explored. The results achieved concern multiple aspects of Roman taxation, focusing on various types of inscriptions, articulated from the microscale to the macroscale, in a precisely multi-scalar study of an extremely diverse Roman world
LARGE EIGENVALUES OF THE INTENSITY-DEPENDENT RABI MODEL
No full textWe prove that the spectrum of the intensity-dependent Rabi Hamiltonian consists of two eigenvalue sequences (E_m^+), (E_m^-), m=0, 1, 2, 3, ... , satisfying a three-term asymptotic formula with the remainder estimate O(m^{−1} ln m) when m tends to infinity. Using the three leading terms of this asymptotic formula, one obtains anapproximation analogous to the generalized rotating-wave approximation for large eigenvalues of the usual quantum Rabi model
Marine foams impede metabolic and behavioural traits in the rough periwinkle Littorina saxatilis
No full textInternational audienceFoams are a ubiquitous feature of marine environments. They can have major economic, societal and ecologicalconsequences through their accumulation on the shore. Despite their pervasive nature and evidence that stablefoam deposits play a pivotal role in the ecology of soft shore and estuaries, very limited amounts of informationare available on their contribution to the structure and function at play in rocky intertidal ecosystems. This studyshows that the metabolic rate of the high-shore gastropod Littorina saxatilis is significantly higher in individualsexposed to foams. Behavioural assays conducted under laboratory-controlled conditions further show that thisspecies detects foam-born infochemicals both indirectly or directly, hence rely on both airborne and contactchemosensory cues. L. saxatilis also actively avoid areas covered in foam, and increase their activity in thepresence of foam. These observations are interpreted in terms of foam-induced increased metabolic stress andincreases behavioural anxiety and vigilance. They are further discussed in relation to the occurrence of twophytoplankton species known to produce repellent and/or toxic compounds such as domoic acid and dime-thylsulfoniopropionate, the diatom Pseudo-nitzschia multistriata and the haptophyte Phaeocystis globosa, with thelatter occurring at unusually high density. Taken together, these results suggest that the accumulation of foamson intertidal rocky shores may have major implications on taxa relying on both airborne and contact chemo-sensory cues to navigate, find food and mating partners. Specifically, the observed increased behavioural activitycoupled with increased metabolic demands may impact species fitness and highlight potentially large ecologicalconsequences in rocky intertidal ecosystems characterized by strong hydrodynamism and elevated organicmatter content leading to the presence of long-lived foam
Locally-Rank-One-Based Joint Unmixing and Demosaicing Methods for Snapshot Spectral Images. Part II: a Filtering-Based Framework
No full textInternational audienceThis paper presents novel unmixing and demosaicing methods for snapshot spectral imaging (SSI) systems utilizing Fabry-Perot filters. Unlike conventional approaches that perform unmixing after image restoration or demosaicing, our proposed methods leverage Fabry-Perot filter deconvolution and extend the "pure pixel" framework to the SSI sensor patch level, enabling improved unmixing accuracy and introducing the concept of localized spectral purity. Through extensive experimentation on synthetically generated data and real images captured by SSI cameras, we demonstrate the superiority of our methods over state-of-the-art techniques. Furthermore, our results showcase the effectiveness of the proposed approach over our recently proposed joint unmixing and demosaicing method based on low-rank matrix completion
CO2 methanation catalysts derived from Ni-alkaline earth metal carbonates
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La prophétie sur Trump, ou comment un film Godlywoodien montre une Amérique divisée
No full textInternational audienceThe present case study is first going to show that The Trump Prophecy, which calls for unity through prayer and celebrates Donald Trump as the only true saviour for America (consequently approving his divisive presidency at the time of its release), is a Godlywood film featuring American conservative Christian values that have in fact increasingly contributed to polarize and divide America at the time of Trump. The article will then show that Trump, the film’s production, its second part and the conditions of its release reflect the on-going division between the conservative evangelical Christians, who contributed to the 2016 election of Donald Trump (and to that of other conservative presidents before him), and a more mainstream and lay part of the United States which did not fail to point out and make fun of the strangeness of the film. Finally, the present case study will highlight that the theme of the film, its production, its second part and the conditions of its release also caused controversy within the evangelical community itself, as some evangelical Christians did not agree with the film’s stance, thus pointing to an even more dis-united America
New line list for the ν4 bands of the trans (790.117 cm–1) and cis (851.943 cm–1) conformers of nitrous acid (HONO): Accurate positions and absolute intensities
No full textInternational audienceThe goal of this work was to update and significantly improve the line lists that have been generated recently for 11 µm bands of the trans- and cis- conformer forms of nitrous acid (HONO) [Armante R, Perrin A, Kwabia Tchana F, Manceron L. The ν4 bands at 11 μm: linelists for the trans- and cis- conformer forms of nitrous acid (HONO) in the 2019 version of the GEISA database. Molecular Physics 2021;120:e1951860]. That 2019 version of the 11 µm line list was generated using the spectroscopic parameters that were available, at that time, in the literature. During the present study, we used high-resolution Fourier transform spectra recorded at 11 µm to perform a large investigation of line positions and intensities for the ν4 bands of the trans- and cis-conformer of HONO. The resulting set of experimental ν4 (absolute) intensities and of 41 energy levels were used to determine, by least squares fit computations, improved position and intensity parameters for the ν4 bands of the trans- and cis-conformer of HONO. For trans-HONO, the ν4 band appeared not to be perturbed, while for cis-HONO a weak high order B-type Coriolis, coupling together the 41 and 61 energy levels was evidenced for the first time. This new list is of potential interest for the IASI-NG (Infrared Atmospheric Sounding Interferometer - New Generation) instrument which will be launched on board the METOP-SG satellite in 2025
