HAL-Ecole des Ponts ParisTech
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A Simple Theory of Deep Trade Integration
No full textInternational audienceWhich countries should aim for regulatory cooperation, and to what extent should they pursue it? We develop an imperfectly competitive trade model that accounts for differences in technology and regulatory preferences regarding local consumption externalities across countries. Each country sets unique product standards, and firms incur costs when tailoring products to different markets. Trade occurs when the benefits of comparative advantages outweigh the desire for asymmetric regulations. Our findings indicate that regulatory cooperation, defined as the cooperative setting of standards, is most advantageous for countries with moderate differences in regulatory preferences. Shallow integration, however, falls short of achieving the optimal planner’s solution. Countries with strong comparative advantages in distinct externality-generating goods can pursue deeper regulatory cooperation through mutual regulatory concessions. Additionally, when regulatory preferences are highly dispersed, international cooperation tends to form regulatory blocs
Maximizing Network Phylogenetic Diversity
No full textNetwork Phylogenetic Diversity (Network-PD) is a measure for the diversity of a set of species based on a rooted phylogenetic network (with branch lengths and inheritance probabilities on the reticulation edges) describing the evolution of those species. We consider the \textsc{Max-Network-PD} problem: given such a network, find~ species with maximum Network-PD score. We show that this problem is fixed-parameter tractable (FPT) for binary networks, by describing an optimal algorithm running in ~time, with~ the total number of species in the network and~ its reticulation number. Furthermore, we show that \textsc{Max-Network-PD} is NP-hard for level-1 networks, proving that, unless PNP, the FPT approach cannot be extended by using the level as parameter instead of the reticulation number
Second generation effects of an experimental conditional cash transfer program on early childhood human capital in Nicaragua
No full textInternational audienceInterventions targeting improvements in human capital are often motivated by their potential to break the intergenerational transmission of poverty from parents to children. This study contributes to the thin evidence base on these links by examining outcomes for children of former program beneficiaries of a conditional cash transfer (CCT) program, capitalizing on randomized variation in the timing and CCT’s impact on maternal human capital. We estimate intent-to-treat (ITT) differential effects on early childhood anthropometric and cognitive outcomes for 0–3-year-old children of program beneficiaries [N=366], as well as effects on key domains including nutrition, health, stimulation and the home environment. We find that moderately higher schooling for mothers (19–22 years old) who were the original program beneficiaries did not translate into improvements in anthropometrics or cognitive outcomes for their children. We also find no effects on behaviors commonly thought to be affected by higher education such as investments in nutrition and preventive health, or stimulation. Early program beneficiary mothers, however, had worse mental health outcomes and were more likely to use violent disciplinary practices such as spanking, threatening and punishing. Findings demonstrate the complexity of intergenerational mechanisms across genetic, biological, environmental and behavioral factors, and also suggest the importance of maternal mental health as a mechanism influencing child outcomes
Toward Brague river flood modelling 3: the impact of culvert representation
No full textInternational audienceThe Brague River (south-east France) has historically been subjected to significant flooding events, notably recently in 2011, 2015 and 2019. This research primarily focuses on the 2015 flood event, which resulted in human loss and significant damage. In the study domain, several hydraulic structures across the river (e.g., under the A8 highway), which can hinder the river flow during extreme flood events. Our objective in this work is to assess the influence of culvert representation within the domain on hydraulic discharge, particularly beneath roadways, and to examine the resultant variations in flood extents and water depth. To this goal, the TELEMAC-2D hydraulic modelling software is used to simulate a range of modelling approaches that account differently for the flow in the culvert areas, such as opened or closed topography or using culvert discharge equations. Five scenarios concerning the highway culverts are proposed. The numerical results are analysed and intercompared with field observations. The results reveal a significant reduction in culverts flow rate upon the formation of logjams, while the highway overflow increases. These studies' findings could help in guiding management policies and practices, offering a scientific foundation for decision-making in the context of flood events involving hydraulic structures
Global supply chains and domestic climate policy Addressing the substantial material-related carbon footprint of final consumption in France
No full textInternational audienceIn the Global North, materials production accounts for a limited share of territorial greenhouse gas (GHG) emissions, and national low-carbon strategies typically focus on direct emissions in the energy, transport, buildings, and agricultural sectors. However, GHG emissions from materials production represent a significant portion of global emissions and are predominantly embodied in imports for these countries. This paper estimates and maps the carbon footprint of materials production (CFM) for France, serving as a representative case study of the Global North, for both the current situation and future scenarios. Our findings indicate that in 2015, the CFM accounted for 3 tCO 2 eq per capita, of which almost 90% were indirect emissions embodied in imports, while emissions from domestic materials production accounted for only 0.7 tCO 2 eq per capita. The CFM is notably distributed across all final consumption sectors, including purchased services, with heterogeneous contributions from different material types. Moreover, the latest national net-zero emissions strategy is projected to reduce the total French carbon footprint by only half by 2050, with 60% of the remaining GHG emissions corresponding to an unchanged CFM from 2015 to 2050. Based on a detailed mapping of present and projected carbon footprints across supply chains and trade, we identify critical areas for policy intervention. Beyond standard international collaborations and incentives aimed at reducing the carbon content of imports (e.g., Carbon Border Adjustment Mechanism, climate clubs, and climate finance), domestic policies fostering greater circularity and reindustrialization, coupled with shifts toward lower-demand lifestyles, emerge as essential strategies for effectively diminishing the CFM
Intense and localized export of selected marine snow types at eddy edges in the South Atlantic Ocean
No full textInternational audienceAbstract. The biological carbon pump (BCP) comprises a wide variety of processes involved in transferring organic carbon from the surface to the deep ocean. This results in long-term carbon sequestration. Without the BCP, atmospheric CO2 concentrations would be around 200 ppm higher. This study reveals that ocean dynamics at the mesoscale and submesoscale could have a major impact on particulate organic matter (POM) vertical distribution. Our results indicate that intense submesoscale frontal regions, such as those between mesoscale eddies, could lead to an important accumulation and transport of POM from the mixed-layer depth (MLD) down to the mesopelagic zone. To reach these conclusions, a multifaceted approach was applied. It included in situ measurements and marine snow images from a BGC-Argo float equipped with an Underwater Vision Profiler (UVP6), satellite altimetry data, and Lagrangian diagnostics. We focused our study on three intense features in marine snow distribution, observed during the 17-month-long float mission in the Cape Basin in the southwest of Africa. These features were located in the frontal region between mesoscale eddies. Our study suggests that a particle injection pump induced by a frontogenesis-driven mechanism has the potential to enhance the effectiveness of the biological pump by increasing the depth at which carbon is injected into the water column. This work also emphasizes the importance of establishing repeated sampling campaigns targeting the interface zones between eddies. This could improve our understanding of the mechanisms involved in the deep accumulation of marine snow observed at eddy interfaces
Hartman-Stampacchia theorem, Gale-Nikaido-Debreu lemma, and Brouwer and Kakutani fixed-point theorems
No full textThis paper uses the Hartman-Stampacchia theorem and its generalized version as the primary tools to prove the Gale-Nikaid\^o-Debreu lemmas. It also establishes a mutual equivalence among the Hartman-Stampacchia theorem, the Gale-Nikaid\^o-Debreu lemmas, and the Kakutani and Brouwer fixed-point theorems
Capacity of the Fungi Trichoderma Koningiopsis and Talaromyces Verruculosus for Hg Leaching, Immobilization and Absorption During the Dissolution of Cinnabar
No full textInternational audienceThe present study investigates the potential capacity of fungi for the use in mercury (Hg) leaching and immobilization during the dissolution of cinnabar ore, the updated understanding of the mechanisms involved, and the evaluation of Hg absorption by these fungal strains. Two fungal strains are isolated from Hg-polluted soils in French Guiana and identified as Trichoderma koningiopsis and Talaromyces verruculosus. These fungal strains possess a high capacity for Hg resistance. The Hg concentrations causing 50% growth reduction (EC50) are 5.9 and 1.5 ppm for T. koningiopsis and T. verruculosus, respectively. The results of medium-culture-containing cinnabar ore show that these fungal strains remove over 99% of the Hg content in the culture media by the end of the experiment. Fungal biomass decreases with increasing mercury concentration. The production of organic acids by fungi is observed for both fungal strains, leading to an acidic pH in the medium culture. Oxalic and citric acids are preferentially produced to dissolve Fe from minerals, which may impact Hg leaching. The results of this study provide evidence that the two fungi seem to have potential use for the bioremediation of Hg during the dissolution of cinnabar ores through biosorption mechanisms
Complete set of broadening coefficients and high-order line-shape parameters for N2-broadened CO2 lines, for temperatures ranging from 100 K to 1000 K
No full textInternational audienceBroadening coefficients and high-order line-shape parameters, including the speed dependence of the line width, Dicke narrowing and first-order line-mixing parameters, are predicted for N2broadened CO2 lines over a temperature range from 100 to 1000 K using requantized molecular dynamics simulations (rCMDS). By employing an intermolecular potential, classical equations of motion, and a requantization procedure, rCMDS enable the calculations of N2-broadened CO2 spectra across a wide temperature range without use of any adjustable parameters. For each considered temperature, line-shape parameters were retrieved from fits of the rCMDS spectra using the Voigt, speed-dependent Voigt, and Hartmann-Tran profiles, with first-order line mixing accounted for. The obtained parameters and their temperature dependences were compared with experimental data at various temperatures showing excellent agreement. We demonstrate that parameters and their temperature dependences obtained at Earth's atmospheric temperatures cannot be used to deduce with accuracy those at higher temperatures, relevant for studies of exoplanetary atmospheres and combustion media. Comparisons with databases show that several parameters and their temperature dependences need to be updated by incorporating accurate high-temperature data to correctly simulate the absorption spectra of N2-broadened CO2 from low to high temperatures