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A simple and transparent method for improving the energetics and thermodynamics of seawater approximations: Static energy asymptotics (SEA)
No full textInternational audienceThe static energy encodes all possible information about the thermodynamics and potential energy (and all related forces) of stratified geophysical fluids. In this paper, we develop a systematic methodology, called static energy asymptotics, that exploits this property for constructing energetically and thermodynamically consistent sound-proof approximations of the equations of motion. By approximating the static energy to various orders of accuracy, two main families of approximations are (re-)derived and discussed: the pseudo-incompressible (PI) approximation and the anelastic (AN) approximation. For all approximations, the background and available potential energies (in Lorenz sense) can be constructed to match their exact counterparts as closely as feasible and to be expressible in terms of the exact (as opposed to ad-hoc) thermodynamic potentials. For hydrostatic motions, the AN approximation (of which the Boussinesq approximation is a special case) has the same structure as that of legacy Seawater Boussinesq primitive equations. The energetics of such models could therefore be made transparently traceable to that of the full Navier–Stokes equations at little to no additional cost, thus allowing them to take full advantage of the Gibbs Sea Water (GSW) library developed as part of the new thermodynamic standard for seawater TEOS-10
L’analyse des antihistaminiques dans les eaux usées : un moyen d’évaluer l’exposition au pollen ?
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Perception, investments, and newborn's outcomes: the perception of a newborn's health and its influence on parental investment and health outcomes: Evidence from ELFE cohort
No full textI study whether the parental perception of a newborn's health affects their investments in the child and their health outcomes later in childhood. I use the medical cutoff of low birth weight (<2.5kg.), a historically standard cutoff used to identify infants at high mortality risk. While the economic literature has already studied the implications similar cutoffs (<1.5kg.) have on children's development, most of it has focused on medical treatments as the primary mechanism. In this paper, I investigate whether parents also respond to this label by adapting their investment decisions. To answer this question, I use the French Longitudinal Study of Children ( Étude Longitudinale Française depuis l'Enfance-ELFE ). Using a regression discontinuity design approach, I find an improvement in nutritional outcomes for those that, on top of being low birth weight, are premature. I do not find strong evidence of direct medical intervention at birth based only on the cutoff. Conversely, I encounter that parents respond to children being labeled low birth weight. This is particularly so when looking at parental investments in pre-term children. While doctors might have an indirect role-through advice and recommendations to parents-ignoring parental responses at birth could lead to an under/overestimation of the returns of early-life interventions by the medical community
Dynamics of Jupiter’s equatorial zone: Instability analysis and a mechanism for Y-shaped structures
No full textInternational audienceJupiter's Equatorial Zone (EZ) is characterized by atmospheric dynamics influenced by strong zonal jets. Initially, we perform a linear stability analysis of two-layer geostrophic flows to explore the growth and evolution of instabilities associated with equatorial jets. Stability diagrams reveal that the most unstable baroclinic modes shift to lower wavenumbers with increasing zonal velocities, indicating sensitivity to the strength of the zonal wind. We show notable differences in phase velocities between barotropic and baroclinic jets. Phase portraits of the dynamic structures of various wave types, including barotropic and baroclinic Kelvin waves, Yanai waves, Rossby waves, and inertia-gravity waves, are illustrated in this analysis. Subsequently, we employ a two-layer moist convective Rotating Shallow Water (2mcRSW) model to investigate the nonlinear interactions between ammonia-driven convective processes in the shallow upper atmosphere and large-scale atmospheric features in Jupiter's EZ. We analyze the evolution of nonlinear instabilities in moist-convective flows by perturbing a background zonal velocity field with the most unstable mode. Findings include the amplification of cyclonic and anticyclonic vortices driven by moist convection at the boundaries of the zonal jets and the suppression of convective vortices in equatorial bright zones. This study underscores the role of moist convection in generating upper atmosphere cloud clusters and lightning patterns, as well as the chevron-shaped pattern observed on the poleward side of the zonal jets. Finally, we propose a novel mechanism for the formation of Y-shaped structures on Jupiter, driven by equatorial modons coupled with convectively baroclinic Kelvin waves (CCBCKWs). This mechanism suggests that Y-shaped structures result from large-scale localized heating in a diabatic environment, which, upon reaching a critical threshold of negative pressure or positive buoyancy anomaly, generates a hybrid structure. This hybrid structure consists of a quasi equatorial modon, a coherent dipolar structure, coupled with a CCBCKW that propagates eastward in a self-sustaining and self-propelled manner. Initially, the hybrid moves steadily eastward; however, the larger phase speed of the CCBCKW eventually leads to its detachment from the quasi equatorial modon. The lifetime of this coupled structure varies from interseasonal to seasonal timescales. Moist convection is a necessary condition for triggering the eastward-propagating structure
Economics of rewilding
No full textInternational audienceRewilding, a concept often defined as an open-ended approach to ecological restoration that aims to establish self-sustaining ecosystems, has gained much interest in recent conservation science and practice. The economic dimensions of rewilding remain understudied, despite repeated calls for research, and we find that synthetic or programmatic contributions to the scientific literature are still missing. Here, we mined Scopus and Web of Science databases through a systematic review, looking for “rewilding” with various economic terms in the peer-reviewed literature, in the English language. We then screened out a 257 references-rich corpus with 14 variables, including the position of rewilding regarding positive and negative economic effects in specific sectors, and geographical or ecological foci. Our corpus amounts to ca. 40% of recent rewilding literature, with a clear emphasis on European study sites and the economic consequences of rewilding initiatives. Rewilding studies often refer to positive economic impacts on tourism and hunting, e.g., through higher income and employment rates, although very few studies properly quantify these. Conversely, most authors find rewilding harms farming, which is threatened by abandonment and damages by wildlife, raising interest in potential EU subsidy regimes. We highlight the surprising paucity of rewilding literature truly focusing on economics and/or providing detailed quantification—with remarkable exceptions. While rewilding’s ecological relevance is no longer in question, demonstrating its economic benefits and sustainability will undoubtedly help scaling up. Thus, we advise rewilders to systematically measure and report investments and outcomes of rewilding initiatives, and to adopt common standards for cost and benefit assessments
High order approximations and simulation schemes for the log-Heston process
No full textInternational audienceWe present weak approximations schemes of any order for the Heston model that are obtained by using the method developed by Alfonsi and Bally (2021). This method consists in combining approximation schemes calculated on different random grids to increase the order of convergence. We apply this method with either the Ninomiya-Victoir scheme (2008) or a second-order scheme that samples exactly the volatility component, and we show rigorously that we can achieve then any order of convergence. We give numerical illustrations on financial examples that validate the theoretical order of convergence. We also present promising numerical results for the multifactor/rough Heston model and hint at applications to other models, including the Bates model and the double Heston model
Un monde en guerre
No full textInternational audienceMalgré les espoirs nourris par les démocraties après la Seconde Guerre mondiale, malgré la tentative de construire un ordre international fondé sur le multilatéralisme et malgré la dissuasion nucléaire, la guerre ne cesse de se rallumer en de multiples points du monde, y compris aux portes de l'Europe. Depuis 2022, la guerre en Ukraine a réactivé d'anciens débats : rationalité et justification morale de la guerre, nature des interactions stratégiques entre acteurs du conflit, mobilisation de la population civile, légitimité et efficacité des sanctions contre l'agresseur. Elle soulève également de nouvelles questions. Du côté de la Russie, la guerre fait-elle l'objet d'un consensus au sein des élites ? Pour l'Union européenne, est-elle l'occasion d'une cohésion approfondie, à l'image de l'accueil coordonné des réfugiés ukrainiens ? Ce conflit illustre également l'étendue des armes et des cibles de guerre, des plus traditionnelles telles que l'eau aux outils de communication les plus modernes.Les douze contributions réunies dans ce volume abordent ces questionnements à l'aide des outils propres à différentes disciplines des sciences sociales et humaines. La plupart se rapportent à la guerre en Ukraine, mais certaines ramènent le lecteur au Moyen Âge ou à l'Antiquité, tandis que d'autres appréhendent la manière d'écrire l'histoire de la guerre ou de la représenter dans une œuvre picturale
Money and Value: The Contribution of The Empire of Value to the Economics and Sociology of Conventions
No full textInternational audienceTrying to understand what goods are worth of is at the very heart of economists’ thinking. The answer traditionally given to this question consists in identifying a certain substance, labor, or utility, as being at its origin. The approach of the economics and sociology of conventions takes a completely different path: value is a sui generis social construct, based on monetary convention. This represents a decisive break with traditional economic approaches. Money institutes value. The power invested in money stems from its collective recognition as a purchasing power. In this sense, like language, money is a community fact; it exists only in the context of its community of use, from which it derives its power. In so doing, the proposed construction is reminiscent of Boltanski and Thévenot’s polity model: money must be seen as the “higher common principle” through which everyone is brought into relationship with others. The desire for money, rather than the search for useful commodities, is the elementary force at the heart of the functioning of commodity production. From this perspective, money can be described as “sovereign”, and the monetary community can be compared to the political community. In both cases, one can see a set of originally separate individuals building, through their association, a collective body that transcends and protects them. The monetary institution, like the state, has the nature of a collective power that the association gives itself when it constitutes itself as a social body
The Great Depression as a Savings Glut
No full textInternational audienceNew data covering 23 countries reveal that banking crises of the Great Depression coincided with a sharp international increase in deposits at savings institutions and life insurance. Deposits fled from commercial banks to alternative forms of savings. This fueled a credit crunch since other institutions did not replace bank lending. While asset prices fell, savings held in savings institutions and life insurance companies increased as a share of GDP and in real terms. These findings provide new explanations for the fall in credit and aggregate demand in the 1930s. They illustrate the need to consider nonbank financial institutions when studying banking crises
Learning About Opportunity: Spillovers of Elite School Admissions in Peru
No full textWe study how the admission of an older schoolmate to an elite secondary school influences the application decisions and admission outcomes of younger students. Our study focuses on the rapid expansion of a nationwide system of highly selective secondary schools in Peru. These schools are free of charge, which enables us to investigate the effect of peers on educational choices in a context with minimal financial barriers. Using a sharp regression discontinuity design, our analysis shows that the admission of an older schoolmate increases the number of younger students who apply (by 17%) and are admitted (by 43%) to this elite school system. The effect on applications is concentrated among students with low socioeconomic status (SES). Our evidence suggests that role models can reduce the socioeconomic aspirations gap by helping high-achieving, low-SES youth to learn about the benefits of attending elite schools and to assess whether such institutions are a good match for them