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Simulation-based impact assessment framework for driving restriction zone policies
No full textInternational audienceConventional methods for predicting emissions predominantly rely on site data-driven regression models, thus failing to evaluate mobility impacts of transport policies. This research demonstrates how agent-based simulation has been used to assess ex-ante impacts of one of these policies, driving restriction zone, enabling policymakers to evaluate and refine such interventions during the design phase. The proposed framework examines impacts on mobility and the environment at various aggregation levels. The case study assesses two policy scenarios with varying tolerance levels for road network access by unauthorized non-residents in residential areas; each one-fifth of non-local drivers is restricted every fifth weekday, based on license-plate digits. The findings reveal that both policies reduce car usage, albeit with a slight cost to traffic efficiency. Additionally, the policies contribute to a notable decrease in CO 2 emissions and local air pollutants across all agent groups, citywide, and more locally
The End of Londongrad? Ownership transparency and Offshore Investment in Real Estate
No full textThis paper studies the impact of beneficial ownership transparency in the British real estate market. In an effort to reduce illicit investment following the invasion of Ukraine, the UK government announced a new law in 2022 requiring offshore companies that owned domestic real estate to identify their ultimate owners in a public register. Using a difference-in-difference framework, we find that new property purchases by companies registered in tax havens fell relative to those made via non-havens, a result consistent with transparency raising the costs of illicit investment. These declines persist even after dropping tax havens favored by Russians, suggesting that the reform drove the decline, rather than sanctions. We do not find strong evidence of price effects nor substitution into ownership through suspicious domestic companies. While the policy does appear to have been effective at deterring some anonymous investment into the British property market, incomplete implementation led some clients to still successfully shield their ownership information, implying scope for better design and enforcement in the future
Is Migration Good for the Public Finances
No full textInternational audienceIs Migration Good for the Public Finances
Modelling oxidative potential of atmospheric particle: A 2-year study over France
No full textInternational audienceThe oxidative potential (OP) of particulate matter (PM) has emerged as a promising indicator of the adverse effects of PM on human health. In particular, OP is an indicator for oxidative stress in biological media through formation of reactive oxygen species. To provide a mapping of the spatial and temporal OP variability over France, we have developed a strategy to simulate the volume-normalized oxidative potential (OPv) in the state-of-the-art CHIMERE air quality model over the metropolitan French territory for the years 2013 and 2014. To do so, we combined a measurement-derived and source specific intrinsic OP (OPi) receptor modelling approach with Particle Source Apportionment Technology (PSAT) in CHIMERE. First, the model's ability to reproduce PM10 concentrations and speciation was verified using in situ observations in mainland France. Furthermore, a mostly satisfying correspondence between receptor model and PSAT outputs was obtained considering their source specific chemical profiles. Simulated versus observed OPv values showed median correlations ranging from 0.35 to 0.60 and mean fractional biases from −30 % to zero, depending on the OP assay considered (ascorbic acid AA, or dithiothreitol DTT) and the PM sources taken into account (i.e. two methods with different PM sources have been used, the reduced and the extended set methods). The modelled two-year average OPv fields show greater spatial hot spots over large urban areas (especially along roadsides) compared to those for PM10 distributions, due to elevated intrinsic OPi values for the primary anthropogenic sources such as traffic and biomass burning. These effects are stronger for the AA compared to the DTT assays, and for a method with a reduced set compared to an extended set of sources. Overall, through the OP apportionment, these results advocate for reinforcing action plans to reduce emissions from road traffic as well as biomass burning emissions
International trade and the allocation of capital within firms
No full textInternational audienceThis paper introduces an internal capital market into a two-factor model of multi-segment firms. It features empire building by managers and informational frictions within the organization. The headquarters knows less about a segment’s true cost than its divisional managers do, so managers can over-report their costs and receive more capital than optimal. Our novel theory, which enables us to endogenize the cost structure of multi-segment firms, shows that international trade imposes discipline on divisional managers and improves the capital allocation between divisions, thereby lowering the conglomerate discount. The theory can explain why exporters exhibit a lower conglomerate discount than non-exporters. We exploit the China shock as an exogenous change to competition to confirm the model’s predictions with data on US companies
The fan token market: reason or passion?
No full textFinance is more and more present in football. In particular, investment funds are now investing in football in large numbers, whether at club or league. Football has not escaped the development of new technologies in the finance sector either. Beyond simple sponsorship, blockchains have enabled the development of certain "crypto assets" specific to football. Many of the best-known clubs now offer their fans "fan tokens" (fungibles), listed on a marketplace, and which allow them to participate in minor decisions about the team's activities. The aim of this article is to better understand how these new markets function, particularly the demand factors and price determination. Are fan token holders mainly supporter-investors or speculators? Is the market efficient? Is the fan token market just a passing trend?La « finance » est de plus en plus présente dans le football. Notamment, les fonds de placementinvestissent aujourd’hui en nombre dans le ballon rond, que ce soit au niveau des clubs ou des ligues. Lefootball n’a pas non plus échappé au développement des nouvelles technologies du secteur de la finance.Au-delà du simple sponsoring, les blockchains ont permis de développer certains « cryptoactifs »spécifiques au football. De nombreux clubs parmi les plus connus proposent aujourd’hui à leurssupporters des « fan token » (fongibles), cotés sur un marché, et qui leur permettent de participer auxdécisions mineures des activités de l’équipe.L’objet de cet article est de mieux comprendre le fonctionnement de ces nouveaux marchés, notammentles facteurs de demande et la détermination des prix. Les détenteurs de fan tokens sont-ils en majorité dessupporters-investisseurs ou des spéculateurs ? Le marché est-il efficient ? Le marché des fan tokens n'est-il qu'une tendance passagère
Deep Learning Techniques for Damage Detection in Structural Health Monitoring: A Review
No full textInternational audienceThis review examines the applications of Deep Learning (DL) in Structural Health Monitoring (SHM) for managing aging civil engineering infrastructures. It focuses on using DL for damage detection, emphasising its advantages over traditional methods in handling large datasets and extracting complex features. It particularly highlights the most used DL architectures like Convolutional Neural Networks and Recurrent Neural Networks applied to SHM approaches, including vibration analysis, computer vision, and nondestructive imaging. The paper also underlines challenges such as data quality, model complexity, and interpretability, and presents emerging solutions including transfer learning, data augmentation, and multimodal data fusion. This work provides a comprehensive overview of the current state and future prospects of DL in SHM
Nonnegative Cross-Curvature in Infinite Dimensions: Synthetic Definition and Spaces of Measures
No full textInternational audienceNonnegative cross-curvature (NNCC) is a geometric property of a cost function defined on a product space originating in optimal transportation and the Ma–Trudinger–Wang theory. Motivated by applications in optimization, gradient flows and mechanism design, we propose a variational formulation of nonnegative cross-curvature on c-convex domains applicable to infinite dimensions and nonsmooth settings. The resulting class of NNCC spaces is closed under Gromov–Hausdorff convergence and for this class, we extend many properties of classical nonnegative cross-curvature: stability under generalized Riemannian submersions, characterization in terms of the convexity of certain sets of c-concave functions, and in the metric case, it is a subclass of positively curved spaces in the sense of Alexandrov. One of our main results is that Wasserstein spaces of probability measures inherit the NNCC property from their base space. Additional examples of NNCC costs include the Bures–Wasserstein and Fisher–Rao squared distances, the Hellinger–Kantorovich squared distance (in some cases), the relative entropy on probability measures, and the 2-Gromov–Wasserstein squared distance on metric measure spaces
Noyaux de réponse dynamiques pour dislocations et fissures : un formalisme lagrangien anisotrope unifié
No full textElastodynamic cohesive-zone models for defects such as cracks or dislocations (such as the Geubelle-Rice model for cracks, or the Dynamic Peierls Equation for flat-core dislocations), feature the same stress-response convolution kernel in space and time. It accounts for in-plane elastic wave propagation, while its associated instantaneous radiative term accounts for radiative losses in the surrounding medium. These objects are well-known for isotropic elasticity, with their space-time representations involving generalized functions. For anisotropic elasticity they were unknown. The paper presents a derivation using the Stroh formalism. Their Fourier representation rests exclusively on the so-called prelogarithmic Lagrangian factor , while their space-time form involves its derivative , the prelogarithmic impulsion function. A straightforward consequence is the reformulation of the stress in the Weertman model of steadily-moving dislocations in terms of . Special care being paid to the causality constraint, the theory covers indifferently subsonic, intersonic and supersonic regimes of motion. The theory proposed is suitable to phase-field-type Fourier-based numerical codes for planar systems of defects in anisotropic elastodynamics
Impact environnemental du furosemide et deux de ses produits de degradation sur la reproduction de Daphnia curvirostris : comparaison des resultats in vivo et in silico
No full textCes travaux sont soutenus par le programme OPUR 6 (2024-2029) piloté par le LEESU et réalisé grâce à la Plateforme Régionale d'Analyse Multi-Milieux des MIcro-ContaminantS (PRAMMICS). Luna Grimault bénéficie d’une bourse de thèse ministérielle. L’abstract a fait l’objet de modifications par rapport à la version originale.International audienceLe furosémide (FUR) est le diurétique de l’anse le plus largement prescrit en Europe depuis les années 1960. Par conséquent, on retrouve largement ce composé dans nos eaux usées. Les stations d’épuration ne permettant pas une élimination totale de nombreuses substances pharmaceutiques présentes dans les eaux usées, une partie du FUR consommé par l’humain est rejetée dans l’environnement. De plus, le FUR est instable et peut se dégrader en une soixantaine de produits différents dont le pyridinium du furosémide (PYR) et la saluamine (SAL). Ces 3 composés ont récemment été quantifiés à des concentrations d’une centaine de ng/L en rivière et à plusieurs milliers de ng/L dans les eaux usées. Peu de données sur l’écotoxicité de ces composés sont disponibles à ce jour. Le FUR, le PYR et la SAL ont récemment montré des effets sublétaux à concentrations environnementales chez Danio rerio. Cependant, le potentiel impact de ces composés sur la reproduction d’organismes non-cibles n’a pas encore été explorée à ces concentrations. Des études in vitro ont pourtant démontré l’induction d’une activité oestrogénique anormale par le FUR à des concentrations de l’ordre du mg/L.Une simulation d’amarrage protéique grâce à Endocrine Disruptome a indiqué une potentielle capacité de fixation de nos 3 composés d’intérêt sur des récepteurs androgéniques, thyroïdiens et glucocorticoïdiens humains. Une affinité similaire probable pour ces mêmes récepteurs a été prédite pour deux hormones endogènes clés de Daphnia curvirostris, la 20-hydroxyecdysone (20E) et le méthyl farnésoate (MF), suggérant des motifs structuraux compatibles avec une fixation spécifique. Réciproquement, si le FUR, le PYR et la SAL peuvent se fixer de la même manière que les hormones endogènes de D. curvirostris sur leurs récepteurs, ces composés pourraient interférer avec des processus physiologiques majeurs tels que la reproduction et la croissance chez cette espèce.Afin de tester cette hypothèse, une étude de reproduction de 15 jours sur deux générations de D. curvirostris a été effectuée à 2000 ng/L. Pour compléter les résultats, une deuxième étude sur une seule génération d’individus a été réalisée avec nos composés en mélange à 50 et 2000 ng/L. L’impact du fénoxycarbe, un insecticide décrit comme perturbateur endocrinien chez D. magna, a également été testé afin de valider notre essai. Les paramètres suivis ont été la fréquence de ponte, le nombre d’individus émis par ponte, la taille des individus émis, ainsi que la taille des individus adultes à la fin de l’exposition. Dans l’ensemble, le FUR, le PYR et la SAL ont montré peu d’effets sur ces paramètres lors des deux expérimentations menées, contrairement au fénoxycarbe.En parallèle, des amarrages protéiques ont été effectués grâce à la suite de logiciels AutoDock, afin d’évaluer l’affinité de FUR, PYR et SAL pour les récepteurs hormonaux de D. magna, ainsi que celles de leurs ligands naturels, le MF et la 20E. Les résultats préliminaires montrent que ces deux hormones se lient à leurs récepteurs avec des affinités conformes à celles décrites dans la littérature. Des travaux complémentaires sont en cours pour déterminer celles de FUR, PYR et SAL pour les deux récepteurs de D. magna, afin d’expliquer les résultats expérimentaux