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Predicting Future Trends of Terrestrial Dissolved Organic Carbon Transport to Global River Systems
No full textInternational audienceA fraction of CO 2 uptake by terrestrial ecosystems is exported as organic carbon (C) through the terrestrial‐aquatic continuum. This translocated C plays a significant role in the terrestrial C balance; however, obtaining global assessments remains challenging due to the predominant reliance on empirical approaches. Leaching of dissolved organic C (DOC) from soils to rivers represents an important fraction of this C export and is assumed to drive a large proportion of the net‐heterotrophy of river systems and the related CO 2 emissions. Using the model JULES‐DOCM, we projected DOC leaching trends over the 21st century based on three scenarios with high (RCP 2.6), intermediate (RCP 4.5), and low (RCP 8.5) climate mitigation efforts. The RCP 8.5 scenario led to the largest DOC leaching increase of +42% to 395 Tg C yr −1 by 2100. In comparison, RCP 2.6 and RCP 4.5 led to increases of 10% and 21%, respectively. Under RCP 8.5, the sub‐tropical zone showed the highest relative increase of 50% above current levels. In the boreal and tropical zones, the simulations revealed similar increases of 48% and 41%, respectively. However, given the pre‐eminence of the tropics in DOC leaching, the absolute increment is markedly substantial from this region (+59 Tg C yr −1 ). The temperate zone displayed the lowest relative increase with 35%. Our analysis identified the rising atmospheric CO 2 concentration and its fertilizing effect on terrestrial NPP as the main reason for the future increase in DOC leaching
Influence of the Liquid Phase on the Aging and Microstructure of Gas Marble
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The multiple temporalities of self-healing infrastructure: from the F-15 fighter to the smart urban microgrid
No full textInternational audienceThe chapter examines the emergence of the smart microgrid as a logic of grid security that can seamlessly switch between ‘normal’ and ‘emergency’ configurations in microseconds. It contributes to further understanding of the evolving temporalities of urban infrastructure configurations in three ways. We first locate the ‘always-on’ uninterruptible capacity of the smart microgrid in a series of concepts, ideas and strategies developed in work on self-healing systems in a variety of contexts. We then trace the development of the smart microgrid in US military and urban contexts, exploring how it has become central to a logic of urban resilience that seeks to mitigate threats and prepare for future turbulence by pursuing the reconfiguration of grids into permanent ‘alert’ mode. Finally, we outline the differential, asynchronous experience of seamless transition enabled by smart microgrids whereby new forms of socio-spatial selectivity are produced through infrastructure temporalities
Targeted and non-target screening of biomarkers in wastewater: towards a unique analytical methodology for sample preparation
No full textInternational audienceThis study aims to optimize a single preparation methodology based on solid-phase extraction (SPE) that could fit both target and non-target screening of organic biomarkers in raw wastewater allowing the cross-comparison of results obtained from a same dataset. The efficiency of SPE sorbents used alone (HLB) or in combination in multilayer cartridge was evaluated based on (i) extraction recovery and matrix effect in environmental samples (surface water and wastewater) for a list of biomarkers (pharmaceuticals, licit and illicit drugs, artificial sweeteners, isoprostanes, polyphenols ) and (ii) by the number of detected features and their intensity in HRMS. The selected method uses a combination of three SPE sorbents mixed together (HLB, X-AW and X-CW) and seems to take fully advantage of each, providing satisfying validation parameters (recoveries, instrumental limit of detection, linearity and range, limit of quantification) over a large range of physical-chemical properties while ensuring promising results for non-target screening application. Of the 65 targeted compounds, nearly all of them (44) were detected in wastewater influent samples with concentration above the limit of quantification while in the same time over 10 000 features were recorded according to the HRMS fingerprint, holding out the promise that a common protocol for these two analyses, with their very contrasting constraints and objectives, is possible
Pluraliser les savoirs pour penser les futurs face à l’incertitude. Le cas de l’effondrement de la falaise d’Ault (Picardie, France)
No full textInternational audienceThe central place of knowledge in public policy choices is being challenged by climate and hydrological phenomena that turn out to be unpredictable and irreversible. This is the case with the retreat of the coastline of the cliffs in Picardy. For a long time based on a scientific and technical approach known as “average retreat”, the national government now has to reconstitute its methods of action in the face of extreme and sudden risks. But it’s not just a question of changing the technical approach, or promoting new prevention tools to build strategies for reorganising coastal areas. The case of the collapse of the cliffs at Ault illustrates the urgent need to integrate multiple forms of knowledge about the effects of climate change into public action, both in terms of alternative and scientific knowledge and in terms of knowledge rooted in sensitive, personal, or aesthetic experience.La place centrale des savoirs dans les choix d’action publique est remise en cause par la « mise en risque » de phénomènes climatiques et hydrologiques qui s’avèrent imprévisibles et irréversibles. C’est le cas du recul du trait de côte des falaises en Picardie. Longtemps basé sur une approche scientifique et technique dite de « recul moyen », l’État doit recomposer ses moyens d’action face à l’occurrence de risques extrêmes et brusques. Or, il ne s’agit pas seulement de changer de modalités dans l’approche technique, ni de promouvoir de nouveaux outils de prévention pour construire des stratégies de recomposition territoriale des littoraux. Le cas de l’effondrement de la falaise d’Ault illustre le besoin urgent d’intégrer dans l’action publique une pluralité de connaissances des effets du changement climatique, tant en termes de savoirs qui peuvent être alternatifs et scientifiques que de connaissances tirées de l’expérience sensible, personnelle ou esthétique
How Gender Norms Shape the Health of Women and Men?
No full textThe role of gender norms in determining women’s and men’s health has been largely overlooked by the economic discipline. This paper is among the first to evaluate the role of social norms on health disparities, a topic that has received limited attention. By combining two European cross-country data sources, I propose a novel approach to measuring gender norms and identifying the causal effect of changes in social norms on individuals’ health. I exploit the European Value Study (EVS) and build time-varying measures of gender norms in the family and the work domains at the country-year level. These measures are then linked with the Survey of Health Ageing and Retirement in Europe (SHARE) data, which is representative at the older population in Europe. I set up an OLS model, including individuals and time-fixed effects, and investigate the role of norms on health status. I show that stronger traditional gender norms in the family increase women’s depression. I also find that more gendered norms at work decrease women’s reporting of poor health. I disentangle some potential mechanisms to test the precise channel by which the type of norm leads to the selected outcomes: financial difficulties, smoking and drinking are among the most critical drivers. Given that reducing gender health inequalities is crucial for fostering an equitable society, targeting neutral gender norms remains a crucial goal of public policie
Elimination des micropolluants pharmaceutiques dans les eaux résiduaires urbaines désinfectées par l’acide perfomique
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Asymptotic and invariant-domain preserving schemes for scalar conservation equations with stiff source terms and multiple equilibrium points
No full textInternational audienceWe propose an operator-splitting scheme to approximate scalar conservation equations with stiff source terms having multiple (at least two) stable equilibrium points. The scheme combines a (reaction-free) transport substep followed by a (transport-free) reaction substep. The transport substep is approximated using the forward Euler method with continuous finite elements and graph viscosity. The reaction substep is approximated using an exponential integrator. The crucial idea of the paper is to use a mesh-dependent cutoff of the reaction time-scale in the reaction substep. We establish a bound on the entropy residual motivating the design of the scheme. We show that the proposed scheme is invariant-domain preserving under the same CFL restriction on the time step as in the nonreactive case. Numerical experiments in one and two space dimensions using linear, convex, and nonconvex fluxes with smooth and nonsmooth initial data in various regimes show that the proposed scheme is asymptotic preserving
Shifting Regimes of Historicity and the Control of Urban Futures through Infrastructures: Continuities, Ambivalences, and Tensions in the Anthropocene
No full textInternational audienceMany imagined social futures and actively promoted ‘transition strategies’ rely on infrastructure development. But to what extent can, or even should, our social futures depend on such infrastructural foundations? This chapter examines infrastructures through three interrelated temporal registers: their lifetimes and life cycles; their day-to-day operation, maintenance, and functioning; and the mediatory role they perform between social pasts, presents, and futures. Drawing from observations of, and insights from, Western (European) urban contexts in which infrastructures are ubiquitous if unequal, it demonstrates how infrastructural environments shape dominant social temporalities by materializing them. The chapter argues that long-industrialized societies have inherited from the modern era a propensity to control social futures through infrastructures but that predominant forms of ‘infrastructure-based futuring’ engender ambivalent and even contradictory implications within the Anthropocene. To address this challenge, the chapter discusses key methodological, epistemological, and political considerations for researching infrastructural, urban-regional, and social futures in the making
L’itinérance touristique : quels enjeux pour les territoires ?
No full textInternational audienceL'itinérance touristique, définie comme une pratique de déplacement continu ou semi-continu dans le cadre d’un voyage, connaît une popularité croissante. À l'ère de l'ultra-connectivité et de la standardisation des expériences, certains touristes recherchent de plus en plus une immersion dans les cultures et les paysages traversés. L'authenticité devient alors un prisme essentiel pour comprendre les motivations et les pratiques des itinérants, mais aussi les impacts de ce mode de tourisme sur les territoires