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Transport in multifractal Kraichnan flows: from turbulence to Liouville quantum gravity
No full textInternational audienceWe investigate the behaviors of fluid parcel trajectories in a multifractal extension of the Kraichnan model of turbulent advection, obtained by coupling one-dimensional monofractal white-in-time Gaussian flows to a frozen-in-time Gaussian multiplicative chaos (GMC). The resulting random flows are characterized by the interplay between a smoothness exponent controlling the correlation decay of the Gaussian component and the intermittency parameter prescribing the deviations from self-similarity. In recent numerical work, this coupling was observed to induce a smoothing effect, whereby two-particle separations exhibit behavior similar to those in (monofractal) Gaussian flows only with increased smoothness exponent. The purpose of this work is to develop a rigorous theory of this phenomenon, contrasting the quenched setting where the GMC has prescribed realization to an annealed setting where the GMC is averaged over. Using the theory of 1D Markov processes we characterize the Lagrangian flow through boundary behaviors at the origin for the two-particle separation process upon varying and . This extends to a multifractal setting the stochastic/deterministic transition and the coalescing/non-coalescing transition well known in the monofractal Kraichnan setting. We show that the separation process present some analogies with multiplicative 1D versions of the Liouville Brownian Motion, a canonical diffusion evolving within a random landscape induced by the GMC and previously introduced in the context of Liouville quantum gravity. In particular, both quenched and annealed phase diagrams are retrieved upon considering a multiplicative Liouville Brownian motion characterized by a smoothness parameter and an intermittency exponent
Coverage of elbow and forearm soft tissue defects with the posterior ulnar recurrent artery perforator flap (PURAP): an anatomical study
No full textInternational audienceIntroduction: Covering soft tissue defects from the elbow and forearm is challenging for the plastic surgeon. The posterior ulnar recurrent artery perforator flap is a fasciocutaneous perforator flap vascularized by the perforators emerging from the posterior ulnar recurrent artery. It has multiple functional and aesthetic advantages but has not yet been well studied. This work aimed to examine the number, caliber, and topography of the posterior ulnar recurrent artery's perforators.Methods: Perforator mapping was performed by blue latex injection on 20 fresh cadavers' upper extremities. Thermal mapping by TIRD was used to identify the \"hot spots\" of these perforators, and the 4D vascular network of the ulnar recurrent artery was scanned. The preoperative design and dissection of the flap were adapted based on the results of this anatomical study. A case study was performed to illustrate the clinical application.Results: On average, we located 7.7 ± 1.7 perforators per upper extremity with an average caliber of 0.77 ± 0.19 mm (3.5 ± 1.2 in the forearm and 4.2 ± 1.5 in the arm). On average, the arm perforators were located 3.2 ± 1.6 cm proximally from the medial epicondyle. Thermal mapping showed three perforator \"hot spots,\" two in the forearm (directly at the artery origin level and one more posteriorly) and one in the arm. The 4D CT reconstructions allowed us to estimate the vascular territory at the level of the medial epicondyle and the distal half of the medial aspect of the arm, as well as the ascending course of the artery.Conclusion: The posterior ulnar recurrent artery perforator flap can be harvested efficiently and reliably, as the posterior ulnar recurrent artery has constant perforators, especially around 3 cm proximal to the medial epicondyle. This reinforces this flap's status as a potential elbow and forearm tissue defect coverage alternative
CAMELS-FR dataset: a large-sample hydroclimatic dataset for France to explore hydrological diversity and support model benchmarking
No full textInternational audienceAbstract. Over the last decade, large-sample approaches, i.e., based on large catchment sets, have become increasingly popular in hydrological studies. Efforts were made to assemble and disseminate national catchment datasets. This article aims to make a contribution to the construction of a large international database of catchments by proposing the CAMELS-FR dataset, a contribution to the CAMELS (Catchment Attributes and MEteorology for Large-sample Studies) initiative. The first version presented here gathers hydroclimatic data and physical attributes for a set of 654 catchments in France. These catchments cover a wide spectrum of hydroclimatic conditions (from oceanic to continental, mountainous, or Mediterranean conditions) and are considered to have limited human influence. Data include time series of daily streamflow (with at least 30 years over the 1970–2021 period, also aggregated to monthly and yearly time steps) and of 11 catchment-scale daily climate variables (including precipitation, potential evaporation, and air temperature), as well as a total of 255 catchment attributes organized into 10 classes (e.g., geology, soil, land cover). River flow time series were quality-checked. Along with the database itself, two graphical tools are proposed, namely dynamic graphs to visualize time series and graphical fact sheets to summarize the main catchment characteristics. Care was taken to provide as many metadata as possible to help users interpret their results based on this dataset. We intend to update the database regularly to include new available data and account for end users' feedback. CAMELS-FR (Delaigue et al., 2024c) is available at https://doi.org/10.57745/WH7FJR
Euclid Quick Data Release (Q1), A first look at the fraction of bars in massive galaxies at
No full textInternational audienceStellar bars are key structures in disc galaxies, driving angular momentum redistribution and influencing processes such as bulge growth and star formation. Quantifying the bar fraction as a function of redshift and stellar mass is therefore important for constraining the physical processes that drive disc formation and evolution across the history of the Universe. Leveraging the unprecedented resolution and survey area of the Euclid Q1 data release combined with the Zoobot deep-learning model trained on citizen-science labels, we identify 7711 barred galaxies with in a magnitude-selected sample spanning . We measure a mean bar fraction of , consistent with prior studies. At fixed redshift, massive galaxies exhibit higher bar fractions, while lower-mass systems show a steeper decline with redshift, suggesting earlier disc assembly in massive galaxies. Comparisons with cosmological simulations (e.g., TNG50, Auriga) reveal a broadly consistent bar fraction, but highlight overpredictions for high-mass systems, pointing to potential over-efficiency in central stellar mass build-up in simulations. These findings demonstrate Euclid's transformative potential for galaxy morphology studies and underscore the importance of refining theoretical models to better reproduce observed trends. Future work will explore finer mass bins, environmental correlations, and additional morphological indicators
La donna senza pace di Maria Catella Giusta, donna senza voce
No full textInternational audienceThe title of my talk contains an allusion to the title of a novel by Maria Catella Giusta, a woman without peace -- in fact, she will die by suicide -- but it stands for her protagonists, women without peace, struggling for love or social justice. Within one of Maria Catella Giusta's novels we detect the presence of a “ woman lecturer.
Parasport : comment donner aux assistants sportifs et aux guides le statut de sportif de haut niveau
No full texthttps://theconversation.com/parasport-comment-donner-aux-assistants-sportifs-et-aux-guides-le-statut-de-sportif-de-haut-niveau-24186
Will We Continue to Use Chaotic Attractors in Science for a Long Time, or Will They only Be a Passing Curiosity?
No full textInternational audienceSince the founding work of Henri Poincar´e in 1889 on the three-body problem, and the paradigm shift in the study of nonlinear dynamical system and the turbulence model occurred in 1970 with the work of Ruelle and Takens who introduced the concept of strange chaotic attractor, numerous applications have emerged in different domains (economics, electronics, cryptography, physics, etc.). We try to describe the evolution of these objects over the last half century and to find out what their place is not only in mathematics, but also for the progress of science, and whether they will be used long into the future
Beyond legal immobility : integrationist tools in Italian naturalisation policy?
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Approcci alla pianificazione ambientale. Risposte frammentarie dalle città andine
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Les habits du social
No full textInternational audienceL’habit fait-il le moine ? Sous son apparente trivialité, l’adage populaire renvoie à la question du lien entre appartenance sociale, politique ou professionnelle et tenue vestimentaire. Souvent vue comme l’expression de choix individuels (« les goûts et les couleurs »), la façon dont on s’habille révèle en réalité l’influence du social sur nos préférences et nos apparences. Comment les rapports sociaux (de classe, de genre, etc.) s’incarnent-ils au quotidien dans le vêtement ? Comment l’analyse des pratiques vestimentaires éclaire-t-elle les évolutions de la société et les débats les plus actuels des sciences sociales ?En explorant par le vêtement la permanence des divisions de classe dans la société, l’incorporation du social dès l’enfance, la place du travail dans la définition des appartenances sociales ou encore les transformations de la représentation politique, cet ouvrage met au jour les déterminismes économiques et sociaux à l’œuvre dans les pratiques vestimentaires d’hier et d’aujourd’hui