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Evaluating Segmentation Using Betti-1 Topological Metric: Application to Nasal Cavities in the context of airflow simulation
No full textInternational audienc
Monitoring of Riverine Aquatic Vegetation Using Satellite PlanetScope Imagery: Feasibility, Limitations and Prospects
No full textInternational audienceSpectral interference induced by the water and the spatial resolution of many satellite images (≥ 10 m) limit the efficiency of remote sensing for monitoring riverine aquatic plant stands. In this study, the potential of using PlanetScope satellite images (3 m in spatial resolution, ~daily acquisition) for monitoring seasonal and interannual aquatic vegetation surface area was evaluated. Airborne images (≤ 0.2 m) acquired on four dates on three aquatic plant stands were used to create, through visual interpretation, reference maps indicating whether the pixels of each PlanetScope image acquired at ±8 days correspond to aquatic vegetation or nonvegetated aquatic areas. For each PlanetScope image, the green normalized difference vegetation index (GNDVI) was calculated and centred on the mean (GNDVI centred ) to distinguish aquatic vegetation from nonvegetated aquatic areas while minimizing variations in their spectral signature over time. Reference maps from the date when aquatic vegetation was the least developed were used to calculate the GNDVI centred classification threshold. To reduce classification errors from radiometric inconsistencies, the frequency at which pixels of PlanetScope images acquired at ±8 days from airborne images were classified as aquatic vegetation was also calculated. Aquatic vegetation was then empirically defined as pixels with a frequency ≥ 85%. Although the classification of PlanetScope images indicates that low abundances of aquatic vegetation cannot be detected, our results show that large changes in stand surface area can be monitored using a multidate classification threshold, thus providing new opportunities for the monitoring of riverine aquatic vegetation on large scales
Hyperpolypharmacy in patients with chronic kidney disease and its impact on clinical outcomes
No full textInternational audienceHyperpolypharmacy (≥ 10 daily medications) is frequent in patients with chronic kidney disease (CKD), but its impact remains poorly characterized. This study, based on 3,011 non-dialyzed, non-transplant CKD outpatients from the CKD-REIN cohort (eGFR < 60 mL/min/1.73 m2) aimed to describe drug burden and assess associations between hyperpolypharmacy and adverse outcomes. Drug prescription, kidney function, adverse drug reactions (ADRs), hospitalizations, kidney replacement therapy and deaths before KRT were prospectively recorded over five years. Median age was 69 years and mean eGFR was 34 mL/min/1.73 m2. At baseline, 80% of the cohort had polypharmacy (≥ 5 daily medications), and 33% had hyperpolypharmacy. These rates remained stable over time. Diabetes, dyslipidemia, and a history of cardiovascular and respiratory diseases were the main contributors to hyperpolypharmacy status. Hyperpolypharmacy was associated with greater likelihoods of an ADR (hazard ratio (HR) [95% confidence interval (CI)] 1.21 [1.04-1.40]), hospitalization (HR [95%CI] 1.34 [1.18-1.51]) and death before KRT (HR [95%CI] 1.46 [1.17-1.82]). Among patients with eGFR ≥ 30 mL/min/1.73m2, hyperpolypharmacy also raised the risk of KRT initiation (HR [95%CI] 1.46 [1.00-2.13]), but not in those with eGFR < 30 (HR [95%CI] 0.94 [0.78-1.14]). These results identify hyperpolypharmacy as a significant concern in CKD and underscore the importance of regular medication reviews to reduce adverse outcomes
Optimal Fidelity Estimation from Binary Measurements for Discrete and Continuous Variable Systems
No full textInternational audienceEstimating the fidelity between a desired target quantum state and an actual prepared state is essential for assessing the success of experiments. For pure target states, we use functional representations that can be measured directly and determine the number of copies of the prepared state needed for fidelity estimation. In continuous variable (CV) systems, we use the Wigner function, which can be measured via displaced parity measurements. We provide upper and lower bounds on the sample complexity required for fidelity estimation, considering the worst-case scenario across all possible prepared states. For target states of particular interest, such as Fock and Gaussian states, we find that this sample complexity is characterized by the L 1 -norm of the Wigner function, a measure of Wigner negativity widely studied in the literature, in particular in resource theories of quantum computation. For discrete variable systems consisting of n qubits, we explore fidelity estimation protocols using Pauli string measurements. Similarly as for the CV approach, the sample complexity is shown to be characterized by the L 1 -norm of the characteristic function of the target state for both Haar random states and stabilizer states. Furthermore, in a general black box model, we prove that, for any target state, the optimal sample complexity for fidelity estimation is characterized by the smoothed L 1 -norm of the target state. To the best of our knowledge, this is the first time the L 1 -norm of the Wigner function provides a lower bound on the cost of some information processing task
Nature-based solutions for water management: Pluridisciplinary state-of-the-art and research needs
No full textInternational audienceNature-based Solutions (NbS) offer a way to preserve, manage and restore ecosystems so as to better meet today's societal challenges, by combining benefits for society and the environment, including biodiversity. They are a response to current climate change-related challenges for water management. However, various barriers exist to the implementation of NbS, such as a lack of appropriation of the concept, as well as needs for knowledge and know-how. Focusing on societal challenges linked to water, we highlight the importance of implementing pluridisciplinary and transdisciplinary projects when trying to implement NbS projects. This requires new approaches in research, practice, and governance. This discussion allows identifying levers for a widespread use of NbS for water management
ZTF SN Ia DR2 follow-up: Characterization of subluminous Type Ia supernovae in the ZTF DR2 full sample
No full textInternational audienceThe Zwicky Transient Facility Data Release 2 (ZTF DR2) includes a total of 3,628 Type Ia supernovae (SNe~Ia), providing the largest and most complete sample of spectroscopically confirmed SNe~Ia at low redshift to date. In this paper, we present a photometric and spectroscopic analysis of 124 subluminous SNe~Ia, the largest sample of spectroscopically classified subluminous SNe~Ia observed with a single instrument, comprising 87 91bg-like, 12 86G-like, 18 04gs-like, and 7 02es-like events. We complement the published DR2 SALT2 light-curve parameters with new parameters obtained using template-based fits from SNooPy. Expansion velocities and pseudo-equivalent widths pEW of key spectral features are measured using Spextractor, and spectral averages are constructed for each subluminous subtype, binned by phase. We also analyze the host galaxy environments, both global and local, in terms of color, stellar mass, and directional light radius . We find that all subluminous SNe~Ia (except the 02es-like subtype) are intrinsically red. This is evident by separating extrinsic from intrinsic color components. Since SALT2 is not trained on subluminous SNe~Ia, it compensates for their redder colors by inflating the parameter, thus extending the luminosity-width relation to negative values of x1. As expected, all subluminous SNe~Ia fall within the Cool region of the Branch et al. (2006) diagram, with the exception of 02es-like events, which show lower Si II 5972 pEW values. All subluminous subtypes tend to occur in more massive, redder host galaxies, and in the reddest local environments. Notably, 91bg- and 86G-like SNe~Ia explode at significantly larger normalized galactocentric distances. Finally, we identify the of the blended Ti II+Si II+Mg II absorption feature at 4300~A, along with s_BV, as robust and sufficient indicators for subclassifying subluminous SNe~Ia
Measurement of the Higgs boson total decay width using the H WW e decay channel in proton-proton collisions at = 13 TeV
No full textInternational audienceThe Higgs boson (H) decay width is determined from the ratio of off- and on-shell production of H WW e using proton-proton collision data corresponding to an integrated luminosity of 138 fb collected at = 13 TeV by the CMS experiment at the LHC. The off-shell signal strength is measured as = 1.2. The Higgs boson total decay width is = 3.9 MeV, in agreement with the standard model prediction. The uncertainty in this result represents a factor of three improvement over the previous CMS result in this decay channel
Token positional games
No full textThe classical Maker-Breaker positional game is played on a board which is a hypergraph H, with two players, Maker and Breaker, alternately claiming vertices of H until all the vertices are claimed. When the game ends, Maker wins if she has claimed all the vertices of some edge of H; otherwise, Breaker wins. Playing this game in real life can be done by placing tokens on the vertices of the board. In this paper, we study the unfortunate case in which one or both players do not have enough tokens to cover all the vertices and, as such, will have to move their tokens around at some point instead of placing new ones. There may be a bias, in that Maker and Breaker do not necessarily have the same amount of tokens. The present paper initiates the study of this generalization of positional games, called token positional games.A particularly interesting case is when Maker has a winning strategy in the classical game: what is the lowest number of tokens with which she still wins against Breaker's unlimited stock? We notably show that, for k-uniform hypergraphs on an arbitrarily large number n of vertices, this number equals k if k ∈ {2, 3} but can vary from k to Ω(n) if k ≥ 4. From an algorithmic point of view, PSPACE-hardness in general is inherited from classical positional games, but we get a polynomial-time algorithm to solve the case where Breaker only has one token. We also establish EXPTIME-completeness for a "token sliding" variation of the game.</div
Contenu du protocole de conciliation homologué versus abus de majorité : l'homologation ne vaut pas absolution
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A new hybrid strongly coupled multi-time step approach with enhanced robustness for fluid structure interaction problems
No full textInternational audienceThis paper presents a strongly coupled approach within the Arbitrary Lagrangian-Eulerian (ALE) framework for solving Fluid-Structure Interaction (FSI) problems, such as those involving a deformable structure in a supersonic flow or subjected to a blast loading. The vertex-centered Finite Volume Method (FVM) for the fluid subdomain with two different explicit time integrators (first-order and third-order accurate Runge-Kutta schemes) is coupled with the Finite Element Method (FEM) for the structural subdomain with an implicit time integrator (Newmark Constant Average Acceleration scheme). This coupling is performed using mono-and multi-time step strategies. The proposed FSI algorithms adopts a monolithic and simultaneous FSI coupling, by introducing Lagrange Multipliers (LM) to ensure the continuity of the normal velocity at the Fluid-Structure (FS) interface. This adopted dual Schur approach allows decoupling the FSI problem into two solid and fluid discrete systems, along with an interface discrete system involving the time-dependent Steklov-Poincaré operator and the unknown Lagrange Multipliers. The proposed approach is hybrid (explicit-implicit), strongly coupled, with fluid subcycling, and is non-iterative in the sense that it does not require any subiteration. It provides a compromise between the flexibility of loosely coupled staggered schemes and the robustness of strongly coupled monolithic formulations. The proposed method has been validated for several academic cases and FSI benchmarks, including the classical half shock tube, the one-dimensional piston problem with a rod, the two-dimensional deformable panel subjected to a shock-wave, as well as a two-dimensional panel flutter problem in the supersonic flow regime