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Collusion in bidding markets: The case of the French public transport industry
No full textInternational audienceWe explore empirically the impact of the market sharing collusive practices that were implemented in the French public transportation industry between 1994 and 1999. We build a structural model of bidding markets where innovating firms compete for the market and have the ability to spread the benefits of their innovation through all markets on which they are active. Each local competitive environment shapes the distribution of the prices (the bids) paid by public authorities to transport operators. We recover empirically the distribution of prices and innovation shocks and we show that collusive practices had overall a limited impact on prices. Firms were in reality more interested in avoiding significant financial risks inherent to the activity, as well as the high cost of preparing a tender proposal. As a by-product, we perform a counterfactual analysis that allows us to simulate how an increase in firms’ innovation reduces prices significantly
From Public Labs to Private Firms: Magnitude and Channels of Local R&D Spillovers
No full textInternational audienceIntroducing a new measure of scientific proximity between private firms and public research groups and exploiting a multi-billion euro financing program of academic clusters in France, we provide causal evidence of local spillovers from academic research to firms in the private sector. Our main estimate suggests that each euro spent in academic research through this program spurred an additional 0.81 euros in private R&D expenditures. We also show that this shock increased the average quality of patents. We exploit reports produced by funded clusters, complemented by data on firm creation, labor mobility and R&D public–private partnerships, to provide evidence on the channels for these spillovers. We discuss the policy implications of funding academic research to stimulate private R&D
Collision induced absorption in HITRAN2024: Enhanced and improved data for atmospheric and planetary studies
No full textInternational audienceCollision-Induced Absorption (CIA) phenomena play a key role in the atmospheric energy balance, making their accurate parametrization a decisive factor in modeling planetary atmospheres. This is the primary reason why the HITRAN spectroscopic database includes a dedicated section for CIAs. This section became available for the first time in 2012, followed by its first update in 2019. Six years since the first update, and with a significant amount of new data now available, it is timely to issue a second update. In this update, new data regarding collisional pairs that appear in the CIA section for the first time ( N2–Ar, and CO2– H2O) are presented. Concerning collisional pairs already present in the database, new data extending both spectral and temperature ranges are available for CO2– CO2, CO2– H2, CO2– CH4, H2– N2, O2– O2, and O2– CO2, while new experimental data about H2– H2 and H2–He have been included alongside the respective theoretical calculations. Data sources, comparisons among different data, and selection criteria, are discussed in detail. The final section is focused on identifying the CIA data that would be most valuable for the planetary science and astrophysics community in the future
L2 -Stability of explicit Runge-Kutta methods with supg stabilization for transient transport problems
No full textWe analyze the approximation of linear transport problems using continuous finite elements in space with SUPG stabilization and explicit Runge-Kutta (ERK) schemes in time. We establish stability for ERK3 and ERK4 schemes in the L2-norm augmented by the mesh-dependent weighted advective derivative induced by the SUPG stabilization. We provide two proofs. The first proof hinges on the stability of Taylor polynomials and covers both ERK3 and ERK4 schemes. The second proof uses more classical energy arguments and covers only ERK3 schemes. This second proof is presented to provide a more direct connection to previous work in the literature. We present numerical experiments illustrating the theoretical findings, including a Fourier analysis in 1D and the approximation of smooth solutions and solutions in BV in 2D. Finally, we briefly discuss the parabolic setting within an implicit-explicit (IMEX) approach, where the diffusion step does not involve the SUPG stabilization. We establish the stability of a simple IMEX scheme in the same norm as above, where a stable ERK scheme is followed by one implicit diffusive step
Coques cimentaire imprimées en 3D et renforcées par fibres longues
No full textInternational audienceCoques cimentaire imprimées en 3D et renforcées par fibres longue
An abstract setting for the Fredholm backstepping transformation: self-adjoint case
No full textIn this paper we address the existence of a Fredholm backstepping transformation for self-adjoint operators A. We prove, under assumptions on the control operator B and A, that there exists a Fredholm backstepping transformation for operators A of order strictly greater than 1. One of the main contribution of the paper is to exhibit the underlying isomorphism used to construct T . This isomorphism allows to deduce sharp estimates on ∥T ∥ L(H;H) and ∥T -1 ∥ L(H;H) with respect to the damping parameter λ > 0. This allow us to prove the finite-time stabilization for a large class of self-adjoint operators.</div
Convention citoyenne sur la fin de vie (France, 2022-2023). Volume 1 : Analyse de la représentativité de la Convention et comparaison des données de l’équipe de recherche avec des données d’enquêtes nationales
No full textLa Convention citoyenne sur la fin de vie (CCFV) (2022-2023) est le deuxième exercice de démocratie délibérative d'envergure à avoir eu lieu en France, après la Convention citoyenne pour le climat (2019-2020). Au cours de la CCFV, des citoyennes et citoyens (essentiellement tirés au sort) ont travaillé au Cese pendant 27 jours, répartis sur neuf week-ends, pour répondre à la question suivante posée par la Première ministre : « Le cadre d'accompagnement de la fin de vie est-il adapté aux différentes situations rencontrées ou d'éventuels changements devraient-ils être introduits ? ». Au cours de la CCFV, les chercheuses et chercheurs, d'un côté, et les animatrices et animateurs, d'un autre, ont administré des questionnaires auprès des conventionnelles et conventionnels.Le présent rapport se compose de deux volumes. Le volume 1 (Apouey, Pénigaud et Santoro, 2025) compare les caractéristiques sociodémographiques des membres de la CCFV avec celles de la population française, ce qui nous conduit à montrer que la CCFV n'était pas vraiment représentative de la population générale. En effet, nous observons à la CCFV une sur-représentation des catégories sociales favorisées et des catégories moyennes (personnes les plus diplômées, cadres, professions intermédiaires) et une sous-représentation des catégories sociales défavorisées. De plus, les habitantes et habitants des communes appartenant à un grand pôle étaient sur-représentés à la CCFV. La représentativité de la CCFV en termes de sexe, d'âge et de région est quant à elle bien respectée. Le volume 1 décrit ensuite le protocole d'observation du déroulement de la CCFV et le processus de passation des questionnaires par l'équipe de recherche. Finalement, nous comparons certaines des données tirées des questionnaires de l'équipe de recherche avec des données d'enquêtes nationales.Le volume 2 (Apouey, Pénigaud, Santoro et al., 2025) rend publics les questionnaires administrés par les équipes de recherche et d'animation et l'ensemble des statistiques descriptives des données (quantitatives) ainsi collectées
Variants of violence: Classifying conflict types and policies for peace
No full textInternational audienceThis paper studies how heterogeneity in conflict determinants and types calls for different policy responses. For this purpose, we propose a novel, data-driven classification of country contexts and corresponding conflict types. We discuss several major conflict-related themes and policy-relevant recipes for curbing fighting
Impact of driving techniques on the lateral behavior of offshore monopile foundations
No full textInternational audienceImpact of driving techniques on the lateral behavior of offshore monopile foundation