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Equivalence Scales Revisited: Evidence from Subjective Data
No full textEquivalence scales (ES) are widely used to compare income levels across different households.Yet the commonly used OECD and square-root scales rely on assumptions about household economies of scale that lack robust empirical support. Using responses to the Minimum Income Question (MIQ) from the European Union Statistics on Income and Living Conditions (EU-SILC) survey, we construct subjective ES based on panel data, rather than relying on pooled OLS as in most previous studies, allowing us to track how income needs evolve within households over time instead of comparing different households. The economies of scale in this subjective scale are notably different from those in traditional ES, and these differences have a substantial effect on the levels and distribution of equivalised income. Based on our empirical findings, we propose a simple alternative to conventional ES and illustrate its implications for poverty and inequality, both within and across countries. Our results show that the choice of equivalence scale significantly influences not only the estimated levels of these variables but also country rankings in comparative analyses.</p
Impact macroéconomique et distributif des réformes françaises des retraites
No full textThe projected five-year increase in life expectancy poses significant challenges to macroeconomic equilibrium, as well as to the financial sustainability and distributional fairness of the French pension system. This paper evaluates the macroeconomic and distributional impacts — both in the medium and long run — of reforms aimed at ensuring the system's sustainability. Calibrated on French data, our model shows that extending working life by 3.3 years, as required to restore the system's financial balance, would increase GDP by 11.7% between 2025 and 2075. This contrasts with a 4% increase in GDP under a scenario involving a 13 percentage point reduction in pension benefits, and with stagnation in the case of a 9 percentage point increase in the contribution rate. Both the postponement of the retirement age and the reduction in pension benefits contribute to a rise in wealth inequality, as a growing share of income is derived from financial assets. The welfare analysis shows that extending the working life is the preferred adjustment scenario.La hausse anticipée de l’espérance de vie de cinq ans pose des défis majeurs à l’équilibre macroéconomique, à la soutenabilité financière ainsi qu’à l’équité distributive du système français de retraite. Cet article évalue les effets macroéconomiques et redistributifs — à moyen et long terme — des réformes visant à assurer la viabilité du système. Calibré sur des données françaises, notre modèle montre que le recul de l’âge de départ à la retraite de 3,3 ans, nécessaire pour rétablir l’équilibre financier du système, permettrait d’augmenter le PIB de 11,7 % entre 2025 et 2075. À titre de comparaison, une baisse de 13 points de pourcentage des pensions n’entraînerait qu’une hausse de 4 % du PIB, tandis qu’une hausse de 9 points du taux de cotisation conduirait à une stagnation. Le report de l’âge de départ à la retraite comme la baisse des pensions entraînent une hausse des inégalités de patrimoine, une part croissante des revenus étant issue des actifs financiers. L’analyse du bien-être montre que le report de l’âge de départ à la retraite constitue le scénario d’ajustement préféré
Anthropogenic intensification of Arctic anticyclonic circulation
No full textInternational audienceThe past four decades have witnessed a strengthening of the winter anticyclonic circulation over the Barents-Kara Sea (BKS), a change that has contributed substantially to amplified local warming and sea ice loss, as well as to Eurasian cooling. However, the cause of this trend in the BKS atmospheric circulation remains unknown. Here we show that anthropogenic greenhouse gases are the primary driver of the strengthening of the BKS anticyclonic circulation, with anthropogenic aerosols playing a secondary role, both together accounting for about 86% of the observed circulation trend. Both forcings induce an amplified BKS low-tropospheric warming through coupling with strong sea ice loss. This amplified warming raises geopotential height aloft through thermal expansion, causing an anomalous anticyclonic anomaly, which in turn enhances warming and sea ice loss, forming a positive feedback loop. Our work provides a theoretical framework for understanding Arctic atmospheric circulation responses to anthropogenic warming and may have implications for climate and environment in the Arctic and beyond
Caractérisation locale et automate minimal de la forme normale alternante dans le monoïde de tresse standard
No full textThe alternating normal form of braids is a well-known normal form on the standard braid monoid. This normal form is regular: the language it identies with is regular. We prove a new characterization of this normal form and its associated language using easily computable braid invariants. This allows us to build its minimal automaton, whose size we compute, both in terms of number of states and of transitions, depending on the number of generators of the monoid. This characterization is also a rst step towards proving stronger results on the alternating normal form, in particular its automaticity
Dynamic assignment without money: Optimality of spot mechanisms
No full textInternational audienceWe study a large market model of dynamic matching with no monetary transfers and a continuum of agents who have to be assigned items at each date. When the social planner can only elicit ordinal agents' preferences, we prove that under a mild regularity assumption, incentive compatible and ordinally efficient allocation rules coincide with spot mechanisms. The latter specify “virtual prices” for items at each date and, for each agent, randomly select a budget of virtual money at the beginning of time. When the social planner can elicit cardinal preferences, we prove that under a similar regularity assumption, incentive compatible and Pareto efficient mechanisms coincide with spot menu of random budgets mechanisms. These are similar to spot mechanisms except that, at the beginning of time, each agent chooses within a menu, a distribution over budget of virtual money
De Kyoto à l’article 6 : retours sur l’histoire mouvementée des mécanismes de coopération
No full textNational audienceAfter 10 years of arduous and complex negotiations, COP29 ended with the final adoption of the main modalities for intergovernmental cooperation on climate change contained in Article 6. However, the new intergovernmental cooperation mechanisms set out in Articles 6.2, 6.4 and 6.8, which are intended to succeed the Kyoto Protocol instruments, are attracting interest from a number of countries and companies seeking to mobilize them to meet their climate change goals. This article examines the reasons behind these stumbling blocks. It shows how three main issues continue to shape discussions on cooperation mechanisms: i) the place of the market in cooperation mechanisms, ii) their environmental integrity, and iii) their ability to meet the needs of developing countries. It also shows that these impasses have manifested in the continuing deadlock in technical discussions on how to operationalize these mechanisms. It then outlines the main issues related to the operational implementation of Article 6 mechanisms.Après 10 ans de négociations laborieuses et complexes, la COP29 s’est achevée sur l’adoption définitive des principales modalités des mécanismes de coopération inclus dans les articles 6.2, 6.4, 6.8, censés prendre la suite des instruments du protocole de Kyoto. L’article analyse les principaux enjeux (place du marché, intégrité environnementale des projets et impact sur le développement durable) et blocages méthodologiques autour desquels les mécanismes de coopération depuis Kyoto se sont structurés. À la lumière des décisions prises à Bakou, l’article éclaire les spécificités institutionnelles de ces instruments et esquisse un certain nombre de perspectives pour leur mise en oeuvre
regularity of the minimizers for the inviscid total variation and Bingham fluid problems for data
No full textInternational audienceThe Bingham fluid model for viscoplastic materials involves the minimization of a nondifferentiable functional. The regularity of the associated solution is investigated here. The simplified scalar case is considered first: the total variation minimization problem. Our main result proves for a convex domain that a right-hand side gives a solution . Homogeneous Dirichlet conditions involve an additional trace term, then implies . In the case of the inviscid vector Bingham fluid model, boundary conditions are difficult to handle, but we prove the local regularity of the solution for . The proofs rely on several generalizations of a lemma due to Br\'ezis and on the viscous approximation. We obtain Euler--Lagrange characterizations of the solution. Homogeneous Dirichlet conditions on the viscous problem lead in the vanishing viscosity limit to relaxed boundary conditions of frictional type
Assessing water quality restoration measures in Lake Pampulha (Brazil) through remote sensing imagery
No full textInternational audienceUrban reservoirs are frequently exposed to impacts from high population density, polluting activities, and the absence of environmental control measures and monitoring. In this study, we investigated the use of satellite imagery to assess restoration measures and support decision-making in a hypereutrophic urban reservoir. Since 2016, Lake Pampulha (Brazil) has undergone restoration measures, including the application of Phoslock®, to mitigate its poor water quality conditions. Satellite images from Landsat-8 (L8) and Sentinel-2 (S2) and historical monitoring data were used to estimate total suspended matter (TSM), chlorophyll-a (Chla), and Secchi disk depth (SDD). We explored both established models from existing literature and novel alternatives, the latter employing machine learning approaches. Model performance was assessed through the coefficient of determination (R2) during calibration and using the root mean square error (RMSE) and its normalization by the observed mean (nRMSE) during validation. Random forest regressor presented superior performance for the three water quality parameters and both satellites. The performance metrics for Landsat-8 were TSM (n=44) R2 of 0.62; Chla (n=48) R2 of 0.74; and SDD (n=23) R2 of 0.67. For Sentinel-2, TSM (n=53) R2 of 0.72; Chla (n=54) R2 of 0.64; SDD (n=33) R2 of 0.89. The selected models were then applied to cloud-free images from 2013 to 2022 to provide modeled TSM, Chla, and SDD values. These were used for spatiotemporal analysis, encompassing cluster analysis, sample comparisons, and trend analysis. Three distinct regions within Lake Pampulha were identified, with the upstream region displaying poorer conditions for TSM, Chla, and SDD. Restoration measures have contributed positively to improving water quality in Lake Pampulha; however, rainy periods pose a challenge due to water quality deterioration associated with urban runoff. Remote sensing has proven to be a robust tool for assisting managers in assessing recovery measures in urban lakes