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LE PROJET «PARI » La datation des glissements de terrain islandais et leur rôle dans l’évolution des paysages
No full textRapport d'activité de l'IPEVLe projet PARI 1266 (PAraglacial Rock-Slope failures dating in Iceland), financé par l’Institut polaire de 2022 à 2025, a pour objectif de dater les glissements de terrain postglaciaires dans les Westfjords islandais et de comprendre leur rôle dans l’évolution des paysages à la fin de la dernière grande glaciation autour de 10 000 ans. Après l’inventaire des dépôts de glissements de terrain aboutissant à une cartographie, un travail de terrain a mobilisé des méthodes de description et de quantification des volumes déposés et de datation (recherches d’éléments datables au carbone 14 dans les séquences sédimentaires, utilisation du marteau de Schmidt). Les résultats obtenus montrent que les glissements de terrain se mettent en place dans les premiers millénaires après le départ des glaciers et que les volumes mobilisés (des millions de m3) au cours de cette crise géomorphologique paraglaciaire contribuent à l’élargissement des vallées glaciaires. Cette ampleur des instabilités passées des versants permet de comprendre les écroulements actuels des parois dans les massifs montagneux de la planète
Community Notes undermoderate polarizing content by design creating risks in electoral processes
No full textCommunity Notes (CNs) of X enables users to collaboratively moderate misleading content. To resolve conflicting moderation, CNs infers a latent ideological dimension and selects notes garnering cross-partisan support. As this system is now deployed worldwide, we evaluate its operation across diverse polarization contexts. We analyze all 1.9 million moderation notes receiving 135 million ratings by March 2025, cross-referencing ideological scaling data on 13 countries. Our results show that the CNs algorithm effectively captures the main polarizing dimensions across countries, surfacing notes that garner cross-partisan support. This also means that, by design, CNs systematically under-moderate polarizing content. We analyze notes relating to four recent elections in the US (2024), the UK (2024), France (2024) and Germany (2025) and demonstrate that they are systematically under-moderated when compared to other notes, posing potential risks to civic discourse and electoral processes
Air Service Agreements, Connectivity and Emissions
No full textThe average energy efficiency of the aviation sector has increased by 2.7 percent per year since 2012, falling short of the 6 percent increase in demand. Optimizing routes by reducing the number of legs per flight is one way to complement technological advances in aircraft and fuels to reduce aviation's environmental footprint. The signature of Air Service Agreements (ASAs) allows airlines to reorganize their flight routes. They reshape the international route network in a more efficient way and ultimately reduce CO 2 emissions per passenger. On the other hand, ASAs increase the demand for international flights, which may offset the reduction in overall CO 2 emissions by airlines. Using unique data on airline tickets and ASAs in force during the period 2012-2019, we show that the considerable reduction in per-passenger CO 2 emissions due to the re-organization of international flight routes induced by ASAs is overcompensated by the additional demand for less time-consuming and, hence, more comfortable international flights
Le « pouvoir d’achat » depuis une cour burkinabè : quelles résonances des prix et des revenus dans les sentiments d’injustice ?
No full textInternational audienceAlthough purchasing power is now a common concern for working-class people around the world, its moral and political understanding varies depending on time and place. This article questions the resonance of repectively prices and incomes on feelings of injustice related to purchasing power, in a society that has never been wage-earning. It draws on research conducted in a working-class neighbourhood of Ouagadougou, Burkina Faso, from the perspective of a family courtyard. The issues considered include daily consumption and work, as well as the everyday understanding of economic concepts, and the socially and historically specific ways in which normative expectations regarding the authorities are formed.Le « pouvoir d'achat » semble constituer une préoccupation partagée par de nombreuses populations à travers le monde, au point que l'on pourrait oublier que cette notion, ou ses diverses traductions, n'a pas forcément les mêmes résonances ici et là, pas plus qu'elle n'a toujours eu la même signification 1 . Aujourd'hui, elle entretient un lien étroit avec le mécontentement social en étant souvent invoquée par (ou au nom) des populations sans pouvoir, dans les périodes où leurs conditions de vie se dégradent. Mais son articulation avec la demande de justice peut se décliner bien différemment selon le lieu et le moment. S'il est attendu qu'une baisse du pouvoir d'achat s'accompagne de difficultés matérielles, il n'est pas évident que ces difficultés suscitent des sentiments d'injustice face à l'autorité politique. Et quand bien même ce serait le cas, il n'est pas non plus certain que ces sentiments s'adossent aux prix, aux revenus ou aux deux à la fois : la sensibilité à ces deux variables ne sera pas forcément la même selon le lieu, le moment, ou encore selon la personne dans un même espace et au même moment. Aussi est-il important de dénaturaliser ce concept de pouvoir d'achat qui, outre les multiples critiques qu'on peut lui adresser, invisibilise la charge morale respective de ses deux composants, les prix et les revenus, telle qu'elle est ressentie par les premiers intéressés. C'est ce à quoi je voudrais m'employer dans cet article, en me plaçant d'un point de vue micro-situé : la cour d'un quartier populaire de Ouagadougou au Burkina Faso.1. Au xix e siècle, l'expression « pouvoir d'achat » était principalement employée par les économistes européens pour désigner la valeur relative des monnaies en fonction des marchandises qu'elles permettaient d'acquérir : ce n'est qu'à partir de la Grande dépression des années 1930 qu'elle fut plus largement associée aux conditions de vie des classes laborieuses (Dreyfus 1935). Le "pouvoir d'achat" depuis une cour burkinabèQuelles résonances des prix et des revenus dans les sentiments d'injustice ?</div
Chinese Grafts in urban production: Perspectives from Cambodia and Thailand
No full textInternational audienceAgainst dominant arguments about a distinctive Chinese urbanism taking shape along the corridors of the Belt and Road Initiative, we argue that Chinese transfers in urban production of Southeast Asia depend on the national and local temporalities of urban and infrastructure development and relate to infrastructure-driven strategies for regional integration. Drawing on a comparison between case studies located in Cambodia and Thailand, we show how Chinese actors are not in a position of control over urbanization processes. Rather, ad hoc arrangements are produced that allow for Chinese transfers to be grafted: into the transitioning urban fabric, onto consortia of actors, development strategies, and programs. The metaphor of the graft helps us analyse how a diversity of Chinese transfers are situated and intertwined along a spectrum that goes from the shiny, flagship projects of the BRI to the shadowy, informal and even illegal, investments in the industrial and construction sectors
A Stone Bead Production Complex from the Beginning of the Indus Civilization at Chanhu-Daro (Sindh, Pakistan)
No full textInternational audienceBetween 2016 and 2020, a massive stone bead workshop associated to dwelling units was discovered at Chanhu-daro site (Trench 2 and 3) and dated to the first period of the Indus Civilization (2600/2500-2300 BCE). A huge amount of different raw materials (e.g. flint, steatite, agate, carnelian, jasper, ernestite) was processed and debitage wastes of both knapping and cutting activities were identified. Tools for manufacturing, perforating or polishing the stone beads (e.g. blades, drills/borers, polishers, hammers, pressure flaker) -some of them unique and exceptionally preserved -were found together. Several beads roughouts, preforms, and finished products were also documented. For the first time (so-far) contextualized data about an intensive craft production from the first Indus period will be discussed. The evidence found at Chanhu-daro site will help reconstructing the whole stone beads manufacturing processes and investigating the related technical system.</div
A comparative analysis of infection and mortality in reassessing africa’s COVID-19 dynamic using time-varying tests
No full textInternational audienceBackground It is commonly believed that Africa largely evaded the worst of the COVID-19 pandemic, with fewer cases than other continents. However, regional comparisons that ignore differences in testing intensity may misrepresent dynamics. Studying the spread and case-fatality relationship during COVID-19 across WHO regions requires explicitly adjusting for time-varying test volumes. Methods We build a weekly panel dataset spanning May 2020 to December 2021 for the WHO regions: Africa, Eastern Mediterranean, South-East Asia, the Americas, Western Pacific, and Europe. Data on tests, confirmed cases, and COVID-19-attributed deaths were sourced from Our World in Data. We apply a novel metric that corrects for fluctuating test volumes to quantify week-to-week acceleration in infections and in mortality. We then compare the frequency, magnitude, and timing of these acceleration episodes across regions.Results Accounting for testing dynamics, we show that Africa exhibits multiple infectionacceleration episodes whose magnitude and frequency match those in other regions. Mortality accelerations in Africa closely follow infection surges, with an average lag of ten weeks. A positive correlation between infection acceleration in Africa and the Americas further indicates synchrony. These findings hold when using a larger secondary dataset of 140 countries. Conclusions Contrary to prevailing assumptions, Africa was not spared from the pandemic's severe dynamics. Infection surges were on par with those elsewhere and were followed by mortality accelerations. These results underscore that accounting for testing variability is essential to accurately assess pandemic progression, and they highlight the urgent need to strengthen surveillance and healthcare capacity across all regions.The relatively low number of reported COVID-19 cases and deaths in Africa has prompted debates about whether the continent was spared the worst of the pandemic, a phenomenon described by some as the African "puzzle" 1,2 or "paradox" 3 . Early media reports and research articles speculated that Africa's younger population, lower population density in rural areas, and prior experience with infectious diseases and their pharmaceutical treatments might have mitigated the severe impacts observed in other regions.However, emerging evidence from seroprevalence studies indicates that far more individuals in Africa were exposed to SARS-CoV-2 than is reflected in official surveillance data, especially during the pandemic's first 2 years. For example, the ratio of seroprevalence to confirmed cases has been estimated to be as high as 100:1 4 . This gap between seroprevalence estimates and reported cases grew as the pandemic continued 5 , suggesting substantial under-reporting in surveillance data. For example, while 6 mention low testing rates as a likely source of under-reporting in their discussion of the</div