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Macroéconomie des transitions énergétiques Explorations dans le cas français par la mise en oeuvre d'un modèle réduit
No full textEstimating the Effects of Regulation When Treated and Control Firms Compete: A New Method with Application to the EU ETS
No full textThis paper presents a method for estimating treatment effects of regulations when treated and control firms compete on the output market. We develop a GMM estimator that recovers reduced-form parameters consistent with a model of differentiated product markets with multi-plant firms, and use these estimates to evaluate counterfactual revenues and emissions. Our procedure recovers unbiased estimates of treatment effects in Monte Carlo experiments, while difference-in-differences estimators and other popular methods do not. In an application, we find that the European carbon market reduced emissions at regulated plants without undermining revenues of regulated firms, relative to an unregulated counterfactual
Stationary solutions and large time asymptotics to a cross-diffusion-Cahn-Hilliard system
No full textCode can be consulted at \url{https://doi.org/10.5281/zenodo.8117581}.International audienceWe study some properties of a multi-species degenerate Ginzburg-Landau energy and its relation to a cross-diffusion Cahn-Hilliard system. The model is motivated by multicomponent mixtures where crossdiffusion effects between the different species are taken into account, and where only one species does separate from the others. Using a comparison argument, we obtain strict bounds on the minimizers from which we can derive first-order optimality conditions, revealing a link with the single-species energy, and providing enough regularity to qualify the minimizers as stationary solutions of the evolution system. We also discuss convexity properties of the energy as well as long time asymptotics of the time-dependent problem. Lastly, we introduce a structure-preserving finite volume scheme for the time-dependent problem and present several numerical experiments in one and two spatial dimensions
Pairing strategic zoning of highly protected areas and rules of access in MPAs: a need for generating cobenefits and operationalize strong protection and sustainability in MPAs
No full textInternational audienc
Animals and Social Welfare
No full textInternational audienceI propose a framework to evaluate the social gains from policies regarding animals. The model considers both the welfare of animals and humans. The gains in animal welfare are estimated by considering the violations of the animals' fundamental freedoms weighted for each species. I apply this framework to twenty policy proposals targeting wild, domestic, farmed, and laboratory animals. Although the policies benefit from widespread popular support in France (the annual willingnesses-to-pay range between 15 and 39 Euros per person per year), I show that they have very heterogeneous impacts on animal welfare (valued at between 0.013 and 3,618 Euros per person per year). I further show that humans' willingness-to-pay for policies improving animal welfare is a poor predictor of the effective impact on animal welfare of these policies. I conclude that it is essential to value animal welfare per se in cost-benefit analyses in order to determine the set of welfare-increasing policies
Persistent generatexes: unveiling the dynamical paths in complex systems
No full textInternational audienc
RNA inverse folding can be solved in linear time for structures without isolated stacks or base pairs
No full textNational audienceInverse folding (IF) is a classic instance of negative RNA design, and consists in finding a sequence that uniquely folds into a target secondary structure with respect to free-energy minimization. Even when base pairs uniformly contribute -1 to the energy, and energy minimization coincides with maximizing the number of base pairs, the (exponential) numbers of potential alternatives over a candidate sequence makes IF a challenging problem to tackle. Accordingly, IF is generally believed to be NP-hard, as formally demonstrated under mild constraints by Bonnet et al. [1]. In recent work [2 ], we show that inverse folding can be solved in linear time for a large collection of targets, including every structure that contains no isolated base pair and no isolated stack, i.e. such that hmin =3 with hmin that denotes the minimum number of base pairs in an helix. This constraint has practical relevance as RNAs are known to contain few helices of small sizes and, even though, such helices are not major contributors to the free-energy/stability. Our approach introduces a notion of modulo m-separability, generalizing a separability property introduced by Hales et al. [ 3 ]. (m-)Separability represents a sufficient condition for the existence of a solution to the inverse folding problem. This allows us to propose a dynamic programming algorithm that, for any input secondary structure of length n, returns a modulo m-separated sequence in time O(2mmn) anytime such a sequence exists.Using this algorithm, we show that every structure with hmin = 3 is either trivially non-designable (if it contains a forbidden motif) or always admits a modulo-2 separated solution (m = 2), which can be obtained in linear time. A trivial extension of our algorithm allows us to uniformly generate them within the set of modulo-2 separable sequences. Further experiments show that structures featuring shorter helices (hmin = 2) are often solved with our algorithm with m ”small” and that our sequences obtained for hmin = 3 represent better candidates than random compatible sequences in the more realistic Turner energy model
Introduction Les communs et leurs promesses. Pour une analyse documentée en matière de transition écologique et sociale
No full textInternational audienceThe intermediary position of the commons approach between public and private management offers the potential for a number of benefits, including improved resource management, a more ecological and fairer society, and emancipation projects. In light of this, it is important for academic research to continue its work of understanding and exploring the conditions raised by the fulfilment of these promises. In this context, the paper identifies four research perspectives. The first concerns the lifecycle of the commons and the consequences for the management of shared resources. The second area of interest concerns the question of work and how to make the most of it in order to perpetuate the commitment of commoners. The third area of interest relates to the acceptance by existing institutional frameworks of the innovations brought about by the commons, and conversely, the risk of capture and distortion of the inventive character by these same institutional frameworks. The final perspective concerns the possible contradictions surrounding the management of the natural commons when these require the renunciation of certain uses. The objective of this special issue is to identify and address the blind spots that currently impede the transition towards an ecological and social transformation. By doing so, it will contribute to the development of a more informed analysis of the challenges and opportunities that this transition presents.De par sa position intermédiaire entre gestion publique et gestion privée, l’approche par les communs est porteuse d’un certain nombre de promesses, que ce soit pour une meilleure gestion des ressources, pour une société plus écologique et plus juste, et pour des projets d’émancipation. Dans ce contexte, la recherche académique se doit de poursuivre son travail de connaissance et d’explorer les conditions soulevées par la tenue de ces promesses. Le papier pointe pour cela quatre perspectives de recherche. La première concerne la prise en compte du cycle de vie des communs et les conséquences à en déduire en termes de gestion des ressources partagées. La deuxième est en rapport avec la question du travail et de sa valorisation en vue de pérenniser l’engagement des commoners. La troisième a trait à l’accueil par les cadres institutionnels existants des innovations portées par les communs, et, a contrario, le risque de capture et de dénaturation du caractère inventif par ces mêmes cadres institués. La dernière perspective porte sur les contradictions possibles autour de la gestion des communs naturels lorsque ceux-ci nécessitent le renoncement à certains usages. Le numéro spécial que nous introduisons participent de l’exploration de ces angles mort et contribuent à une analyse documentée afin de consolider le chemin vers une transition écologique et sociale
Vélo et pandémie du Covid-19 : une structuration multiscalaire du réseau associatif en Île-de-France
No full textInternational audienceResearch on the Covid-19 pandemic highlights it as a catalyst for significant changes in mobility patterns. The health crisis sparked a renewed focus on cycling as a viable mode of daily transportation and prompted new public policies, including support for bicycle repairs and the establishment of temporary cycling infrastructure known as "coronapistes". This article investigates the development of the pro-bike association network in the Île-de-France region, examining its evolution from 1970 to 2023 and analyzing its spatial dynamics. It poses the question: To what extent did the Covid-19 crisis act as a catalyst for ongoing processes, or did it serve as a driver for more transformative change? Drawing on both quantitative data (a census of associations) and qualitative insights (narratives of organizational histories, interviews with association members, local authorities, and institutions), the research compares two sets of data: one collected prior to 2020 and another gathered afterward. The findings indicate that the advocacy efforts of these associations have played a crucial role in establishing cycling as a legitimate mode of transport in the Paris region. Although the foundations of these pro-bike discussions were laid well before the Covid-19 crisis, the pandemic has significantly enhanced the legitimacy, structure, and effectiveness of the associated movements. The degree of this impact varies based on the level of action involved.Los trabajos realizados en torno a la pandemia de Covid-19 presentan a esta última como un evento que propició cambios radicales en términos de movilidad. La crisis sanitaria permitió renovar el debate sobre la bicicleta como medio de transporte cotidiano y avanzar en términos de políticas públicas (apoyo para la reparación de bicicletas, ciclovías provisorias tales como las "coronapistas"). Este artículo estudia la estructuración de la red asociativa pro-bicicleta en la región parisina de Île-de-France, analizando sus dinámicas espaciales y evolución entre 1970 y 2023. ¿En qué medida la crisis del Covid-19 aceleró los procesos en curso?, ¿de qué manera propició cambios más radicales? El artículo utiliza datos cuantitativos (censo de asociaciones) y cualitativos (relatos de historias asociativas, entrevistas con actores(as) asociativos, entidades territoriales e instituciones) recopilados antes y posteriormente del año 2020. Los principales resultados expresan que el papel de la defensa asociativa ha permitido consolidar a la bicicleta como un medio de transporte validado en Île-de-France. Si estos discursos a favor de la bicicleta son anteriores a la crisis de Covid 19, han permitido que el mundo asociativo obtenga legitimidad, estructura y capacidad de acción. Este refuerzo se materializó de manera diferenciada según las escalas de acción.Les travaux réalisés autour de la pandémie de Covid-19 présentent cette dernière comme une période de changement radical en matière de mobilité. La crise sanitaire a permis de renouveler les discours sur le vélo comme mode de déplacement quotidien et de franchir de nouvelles étapes en matière de politiques publiques (aides à la réparation de vélos, aménagements cyclables provisoires tels que les "coronapistes"). Cet article étudie la structuration du réseau associatif pro-vélo en Île-de-France, en analysant ses dynamiques spatiales et son évolution de 1970 à 2023. Dans quelle mesure la crise du Covid-19 a-t-elle constitué un accélérateur des processus en cours, ou bien un levier de changements plus radicaux ? L’article mobilise des données quantitatives (recensement d’associations) et qualitatives (récits d’histoires associatives, entretiens d’acteur.rice.s associatifs, de collectivités territoriales et institutions) issues de deux corpus : l’un constitué avant 2020, l’autre après cette date. Les principaux résultats montrent que le rôle de plaidoyer associatif a permis d’ancrer le vélo comme moyen de transport crédible en Île-de-France. Si ces discours pro-vélo sont bien antérieurs à la crise du Covid 19, celle-ci a permis au monde associatif de gagner en légitimité, en structuration et en capacité d’action. Ce renforcement s’est traduit différemment en fonction des échelles d’action
Neural network approaches for variance reduction in fluctuation formulas
No full text42 pages, 8 figuresWe propose a method utilizing physics-informed neural networks (PINNs) to solve Poisson equations that serve as control variates in the computation of transport coefficients via fluctuation formulas, such as the Green--Kubo and generalized Einstein-like formulas. By leveraging approximate solutions to the Poisson equation constructed through neural networks, our approach significantly reduces the variance of the estimator at hand. We provide an extensive numerical analysis of the estimators and detail a methodology for training neural networks to solve these Poisson equations. The approximate solutions are then incorporated into Monte Carlo simulations as effective control variates, demonstrating the suitability of the method for moderately high-dimensional problems where fully deterministic solutions are computationally infeasible