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Measurement of multidifferential cross sections for dijet production in proton-proton collisions at = 13 TeV
No full textInternational audienceA measurement of the dijet production cross section is reported based on proton-proton collision data collected in 2016 at = 13 TeV by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of up to 36.3 fb. Jets are reconstructed with the anti- algorithm for distance parameters of = 0.4 and 0.8. Cross sections are measured double-differentially (2D) as a function of the largest absolute rapidity of the two jets with the highest transverse momenta and their invariant mass , and triple-differentially (3D) as a function of the rapidity separation , the total boost , and either or the average of the two jets. The cross sections are unfolded to correct for detector effects and are compared with fixed-order calculations derived at next-to-next-to-leading order in perturbative quantum chromodynamics. The impact of the measurements on the parton distribution functions and the strong coupling constant at the mass of the Z boson is investigated, yielding a value of = 0.1179 0.0019
Convergence d'un système de Zakharov stochastique vers l'équation de NLS multiplicative
No full textInternational audienceWe study the convergence of a Zakharov system driven by a time white noise, colored in space, to a multiplicative stochastic nonlinear Schrödinger equation, as the ion-sound speed tends to infinity. In the absence of noise, the conservation of energy gives bounds on the solutions, but this evolution becomes singular in the presence of the noise. To overcome this difficulty, we show that the problem may be recasted in the diffusion-approximation framework, and make use of the perturbed test-function method. We also obtain convergence in probability. The result is limited to dimension one, to avoid too much technicalities. As a prerequisite, we prove the existence and uniqueness of regular solutions of the stochastic Zakharov system.Nous étudions la convergence d'un système de Zakharov forcé par un bruit blanc temporel, coloré en espace, vers une équation de Schrödinger non linéaire stochastique multiplicative. En l'absence de bruit, la conservation de l'énergie donne des bornes uniformes sur les solutions, mais cette évolution devient singulière en présence du bruit. Pour surmonter cette difficulté, nous montrons que le problème peut être replacé dans le cadre de l'approximation-diffusion, et nous utilisons la méthode de la fonction-test perturbée. Nous obtenons également une convergence en probabilité. Le résultat est limité à la dimension un, pour éviter trop de technicité. En préambule, nous prouvons l'existence et l'unicité de solutions régulières du système de Zakharov stochastique
A randomised study comparing performance and safety of Eyestil Plus® vs Vismed Multi® in moderate-to-severe dry eye syndrome patients
No full textInternational audiencePURPOSE: This clinical investigation compared the performance and safety of Eyestil Plus® (SIFI) and Vismed Multi® (TRB Chemedica) for reducing keratitis lesions in moderate-to-severe dry eye disease (DED) patients. MATERIALS AND METHODS: This was a randomised, double-blind, multicentre investigation. 96 adults (>18 years of age) with moderate-to-severe DED received Eyestil Plus® (N = 48) or Vismed Multi® (n = 48) 6 times daily for 3 months. The primary objective clinical performance after 1 month as global corneal and conjunctival staining scores. The secondary objectives were clinical performance after 3 months, tear film stability (tear break up time (TBUT), tear production (Schirmer test), patient-reported outcomes (PROs), investigator satisfaction, and safety. RESULTS: 96 participants were randomised to receive the clinical investigations' treatments, 82.3% of them were female and their mean age was 65.8 years. The non-inferiority of Eyestil Plus® for moderate-to-severe DED was demonstrated at 1 month. No statistical difference was found for any of the study's objectives: change at 1 and 3 months of the global corneal and conjunctival staining score (p-value = 0.506 and 0.661, respectively), change at 1 and 3 months (p-value = 0.538 and 0.302) for TBUT test; change at 3 months for Schirmer test (p-value = 0.540). There were no changes for PROs either. Investigator satisfaction was high for both products. 16.6% of the participants experienced adverse events. CONCLUSION: This clinical investigation showed the non-inferiority of Eyestil Plus® compared to Vismed Multi® regarding performance and safety in a moderate-to-severe DED population
Agricultural fertilization significantly enhances amplitude of land-atmosphere CO2 exchange
No full textInternational audienceObservations show an increase in the seasonal cycle amplitude of CO2 in northern latitudes over the past half century. Although multiple drivers contribute, observations and inversion models cannot quantitatively account for the factors contributing to the increased CO2 amplitude and older versions of Earth System Models (ESMs) do not simulate it. Here we show that several current generation ESMs are closer to the observed CO2 amplitude and highlight that in the Community Earth System Model (CESM) agricultural nitrogen (N) fertilization increases CO2 amplitude by 1-3 ppm throughout the Northern Hemisphere and up to 9 ppm in agricultural hotspots. While agricultural N fertilization is the largest contributor to the enhanced amplitude (45%) in Northern Hemisphere land-atmosphere carbon fluxes in CESM, higher CO2 concentrations and warmer temperatures also contribute, though to a lesser extent (40% and 18% respectively). Our results emphasize the fundamental role of agricultural management in Northern Hemisphere carbon cycle feedbacks and illustrate that agricultural N fertilization should be considered in future carbon cycle simulations
Biodiversity monitoring efforts: a contribution of social sciences, public and environmental economics through measuring the "Biodiversity footprint“ ?
No full textInternational audienceA multi-disciplinary approach through social sciences and natural sciences is suggested to overcome the limitations of monodisciplinary approaches, which measure only one dimension of the observed quantity and may be limited to a simple count without providing the means to control the evolution of the biodiversity
VRSurf: Surface Creation from Sparse, Unoriented 3D Strokes
No full textInternational audienceAlthough intuitive, sketching a closed 3D shape directly in an immersive environment results in an unordered set of arbitrary strokes, which can be difficult to assemble into a closed surface. We tackle this challenge by introducing VRSurf, a surfacing method inspired by a balloon inflation metaphor: Seeded in the sparse scaffold formed by the strokes, a smooth, closed surface is inflated to progressively interpolate the input strokes, sampled into lists of points. These are treated in a divide-and-conquer manner, which allows for automatically triggering some additional balloon inflation followed by fusion if the current inflation stops due to a detected concavity. While the input strokes are intended to belong to the same smooth 3D shape, our method is robust to coarse VR input and does not require strokes to be aligned. We simply avoid intersecting strokes that might give an inconsistent surface position due to the roughness of the VR drawing.Moreover, no additional topological information is required, and all the user needs to do is specify the initial seeding location for the first balloon.The results show that VRsurf can efficiently generate smooth surfaces that interpolate sparse sets of unoriented strokes.Validation includes a side-by-side comparison with other reconstruction methods on the same input VR sketch. We also check that our solution matches the user's intent by applying it to strokes that were sketched on an existing 3D shape and comparing what we get to the original one
Toward more robust net primary production projections in the North Atlantic Ocean
No full textInternational audiencePhytoplankton plays a crucial role in both climate regulation and marine biodiversity, yet it faces escalating threats due to climate change. Understanding future changes in phytoplankton biomass and productivity under climate change requires the utilization of Earth system models capable of resolving marine biogeochemistry. These models often differ significantly from one another, and most studies typically use the average response across an ensemble of models as the most reliable projection. However, in the North Atlantic, this straightforward method falls short of providing robust projections of phytoplankton net primary production (NPP) over the 21st century. A new inter-comparison approach was therefore developed and applied to eight models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6) exhibiting substantial divergence in their NPP projections in the North Atlantic. The basin was first divided into three bioregions tailored to the characteristics of each model using a novel method based on a clustering procedure. The mechanisms controlling NPP projections were then identified in each model and in each bioregion, revealing two mechanisms responsible for a large part of model divergence: diazotrophy in the subtropical region and the presence of an ammonium pool in the subpolar region. This allowed for an informed selection of models in each region based on the way they represent these two mechanisms, resulting in reduced projection uncertainty, enhanced total NPP decrease in the subtropical region, and a strengthened increase in small phytoplankton NPP in the subpolar North Atlantic. These model selections enhanced the decreases in carbon export and phytoplankton biomass but had no impact on zooplankton biomass. This innovative approach has strong synergies with other widely used inter-comparison techniques, such as emergent constraints, and their combination would provide valuable insights into the future trajectory of the Earth's climate syste
Do Skilled Migrants Compete with Native Workers?
No full textInternational audienceSkilled migration is seen as a solution against skill shortages, but its impact on native workers facing increased competition remains debated. To investigate the longer-term potential for displacement, this paper exploits a 2008 reform in France facilitating the hiring of foreign workers within a list of tight occupations. The analysis relies on administrative data and applies a difference-in-differences approach. Results show that the reform successfully boosted migrant hires without affecting native employment. In addition, the negative pressure on occupational wages is much larger among migrants than natives, suggesting that such policies can be a viable solution in the long run
The Spiral of Silence in Multi-agent Models for Opinion Formation
No full textInternational audienceWe generalize the classic multi-agent DeGroot model for opinion dynamics to incorporate the Spiral of Silence theory from political science. This theory states that individuals may withhold their opinions when they perceive them to be in the minority. As in the DeGroot model, a community of agents is represented as a weighted directed graph whose edges indicate how much agents influence one another. However, agents whose current opinions are in the minority become silent (i.e., they do not express their opinion). Two models for opinion update are then introduced. In the memoryless opinion model (SOM -), agents update their opinion by taking the weighted average of their non-silent neighbors' opinions. In the memory based opinion model (SOM + ), agents update their opinions by taking the weighted average of the opinions of all their neighbors, but for silent neighbors, their most recent opinion is considered. We show that for SOM -convergence to consensus is guaranteed for clique graphs but, unlike for the classic DeGroot, not guaranteed for strongly-connected aperiodic graphs. In contrast, we show that for SOM + convergence to consensus is not guaranteed even for clique graphs. We showcase our models through simulations offering experimental insights that align with key aspects of the Spiral of Silence theory. These findings reveal the impact of silence dynamics on opinion formation and highlight the limitations of consensus in more nuanced social models
Torrential rainfall with severe flooding associated with a baroclinic disturbance on November 17, 2023, United Arab Emirates (UAE)
No full textInternational audienceThis work examines a severe weather event caused by a baroclinic disturbance with heavy rainfall and thunderstorms, which struck parts of the UAE and caused major flooding on November 17, 2023. A low-pressure trough extending from the Red Sea Trough (RST) towards the Eastern Mediterranean (EM) led to extreme flooding. The unique intensity of this heavy rainfall was correlated to midlatitude disturbance amplification even in the middle and upper tropospheric produced by RST. During the rain event, two intense moisture sources were injected into the region: one from the Indian Ocean, carried by southeasterly near-surface winds at 10m, and the other from the Red Sea and Equatorial Africa, transported at a mid-tropospheric level. A significant temperature gradient with ~8 °C difference in surface temperatures, particularly between the northern areas in contrast with the southern regions, and the wind shear formation over the northern parts of the study area initiated the baroclinicity structure in the borderlines of the cold front and thunderstorms. The findings also revealed an abnormal westerly jet stream intensification at 200 hPa, associated with a negative meridional wind anomaly, signaling the stretching of a Rossby wave over the study area during the heavy rainfall and flooding.</div