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Une appréciation critique de l"impôt Zucman"
No full textInternational audienceThis article offers a legal characterisation of the proposal for a minimum tax on ultra-high net worth individuals. Although presented as a wealth tax, the project submitted to the G20 in 2024 operates as a hybrid corrective mechanism built on deemed income and anchored in a notion of “economic income”. This conceptual shift moves the benchmark of tax burden from realised income to the wealth stock. The proposed tax base neutralises certain wealth-structuring strategies in abstracto, replacing a case-by-case anti-avoidance logic with a general minimum-tax threshold. The debate therefore shifts from the characterisation of abuse of law to the legitimacy of minimum taxation of net wealth.Turning the average return on capital (2%) observed over forty years into a rule of law creates a potential disconnect between tax liability and realised or disposable income, raising liquidity issues and a risk of excessive taxation unless corrective mechanisms are introduced (capping mechanism; rebuttable presumption). Dutch “Box 3” case-law illustrates the vulnerability of notional income taxation when the fiction may exceed reality. “Payment in kind” through the transfer of shares, presented as a liquidity solution, is legally ambivalent: it may entail forced dilution of shareholding structures and in tension with fundamental freedoms, especially for private (non-listed) participations.The effectiveness conditions for such a regime are not currently met: it requires significantly stronger information and traceability of assets (including non-financial assets), as well as a coherent method for crediting foreign taxes. The claimed parallel with Pillar Two is moreover fragile for individuals, not least in the absence of an individual “consolidated” accounting baseline. Finally, the mechanism presupposes an unlimited residence-state taxing power over worldwide wealth: it therefore sits outside the architecture of bilateral tax treaties and is in tension with ongoing UN work on wealth taxation, which tends towards an allocation-based approach to taxing rights.L’article propose une qualification juridique de la proposition d’une imposition minimale des très hauts patrimoines. Présenté comme un impôt sur la fortune, le projet soumis au G20 en 2024 fonctionne en réalité comme un correctif hybride fondé sur des revenus présomptifs et adossé à une notion de « revenu économique ». Cette bascule conceptuelle déplace l’étalon de la charge fiscale du revenu réalisé vers le stock patrimonial. L’assiette de l’impôt proposé neutralise in abstracto certaines structurations patrimoniales, en substituant à une logique casuistique anti-abus un mécanisme de plancher général. Le débat est ainsi déplacé du terrain de la qualification d’un abus de droit vers celui de la légitimité d’une imposition minimale.Ériger le rendement moyen du capital (2 %) sur quarante ans en règle de droit introduit une possible déconnexion entre la charge fiscale et des revenus réalisés/disponibles, avec des problèmes de liquidité et un risque de caractère excessif, sauf mécanismes correctifs (plafonnement, preuve contraire). Le contentieux néerlandais « Box 3 » illustre la vulnérabilité d’un système de rendement forfaitaire lorsque la fiction excède la réalité. La solution de paiement en nature par remise de titres, avancée pour traiter la liquidité, est juridiquement ambivalente : elle peut emporter dilution contrainte de l’actionnariat et se trouve en tension avec la liberté d’entreprendre, surtout pour les participations non cotées.Les conditions d’efficacité d’un tel dispositif ne sont, à ce jour, pas réunies : ce dernier suppose une capacité d’information et de traçabilité des actifs (y compris non financiers) nettement plus robuste, ainsi qu’une imputation cohérente des impôts étrangers. Le parallélisme avec le Pilier 2 est en outre fragile pour les personnes physiques, faute notamment de référentiel comptable consolidé. Enfin, le mécanisme postule une compétence illimitée de l’État de résidence sur le patrimoine mondial : il se situe ainsi hors architecture des conventions fiscales bilatérales et en tension avec les travaux onusiens en cours sur la fiscalité du patrimoine, orientés vers un partage du pouvoir d’imposer
Biodiversity of Aspergillus section Flavi species isolated along the peanut paste production chain in Côte d'Ivoire
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616500/) * Autres projets (id;sigle;titre): DCI-NSAPVD-2010-64;3CI;(EU) 3C Ivoire project//International audienceThe contamination of staple foods by mycotoxins is a significant issue in sub-Saharan Africa, particularly the presence of aflatoxins in raw peanuts and peanut-based products. This contamination has severe health and economic consequences. The main aflatoxin-producing fungi belong to Aspergillus section Flavi and are grouped in three main clades: A. flavus, A. tamarii and A. nomius, newly qualified as Flavi, Kitamyces and Nomiarum series respectively. The present study assessed the biodiversity of Aspergillus section Flavi species along the peanut paste production chain in the Korhogo region in northern Côte d'Ivoire. A polyphasic approach was used to identify 256 potentially aflatoxigenic strains isolated on AFPA medium. Experiments included (i) morphological characterization, (ii) aflatoxin production on PDA medium, (iii) molecular identification using a PCR-DGGE method and DNA sequencing, and (iv) phylogenetic analyses. Three species of A. flavus clade were isolated. The most prevalent was A. flavus, which comprised mainly aflatoxin-producing strains but also atoxigenic strains, followed by A. aflatoxiformans and A. korhogoensis. The latter two produced B and G aflatoxins at higher levels than A. flavus, which only produced B aflatoxins. A. aflatoxiformans, A. korhogoensis and aflatoxigenic A. flavus strains were mainly isolated after the stages of peanut pod drying and storage in villages, as well as after seed storage by wholesalers and retailers. However, AF production requires confirmation on most appropriate inducing media. The study also indicates that the PCR-DGGE method when combined with a multi-locus phylogenetic analysis is an effective strategy for discriminating and identifying Aspergillus section Flavi species, particularly those in the A. flavus clade
THE HUMAN DIMENSION OF REWILDING IN THE MASCARENE ISLANDS: MAKING SPACE FOR GIANT TORTOISES
No full textInternational audienceThe Mascarene Islands, and Réunion Island in particular, are facing major ecological challenges due to habitat degradation and the pervasive impact of invasive species. In response, researchers, conservation practitioners, and community volunteers have been exploring alternative restoration strategies. One such initiative emerged during the 2019 Island Biology Conference in Réunion, where an experimental rewilding protocol involving the introduction of Aldabra giant tortoises into tropical dry forest ecosystems was proposed. Through a thematic analysis of semi-structured interviews and participant observation, this study examines the complex socio-ecological dynamics surrounding this proposal. Using a conservation approach that challenges traditional methods, the paper highlights the contrasting views among stakeholdersranging from enthusiasm to deep skepticism. While the reintroduction of giant tortoises holds promise for restoring ecological functions such as seed dispersal and herbivory, the project raises ecological, institutional, and cultural concerns, particularly within the densely inhabited and tightly regulated context of Réunion
Type I IFN autoantibodies underlie chikungunya live-attenuated vaccine encephalitis
No full textInternational audienceHuman autoantibodies neutralizing type I interferons (IFNs) have emerged as strong, common, and global determinants of a growing number of severe viral diseases, including hypoxemic viral pneumonia, arboviral encephalitis, and adverse reaction to the live-attenuated yellow fever virus (YFV) vaccine. Chikungunya virus (CHIKV) is a growing global health concern that the live-attenuated vaccine VLA1553 (IXCHIQ®) was developed to address. In 2025, five unrelated adults (aged 82 to 88) on the island of La Réunion (France) developed severe reactions postvaccination; two died. The three patients with encephalitis (aged 84 to 85), including one lethal case, had immunoglobulin G autoantibodies in the blood neutralizing high concentrations of both IFN-α and -ω on admission. An 82-y-old survived rhabdomyolysis without encephalitis, and an 88-y-old died during hospitalization following CHIKV infection despite late vaccination; both lacked autoantibodies against type I IFNs. Autoantibodies neutralizing type I IFNs underlie all three cases of live-attenuated CHIKV vaccine encephalitis studied. Individuals with autoantibodies neutralizing type I IFNs should not be inoculated with live-attenuated YFV and CHIKV vaccines
Multiseasonal modeling of pesticide resistance in maize stalk borer
No full textInternational audienceThis study presents a comprehensive approach to modelling the infestation of maize by the maize stalk borer (Busseola fusca) using both chemical control and cultural practices consisting of post-harvest residue management. Two distinct mathematical models are developed: a semi-discrete integro-differential model and a semi-discrete differential model, each addressing different aspects of pest resistance. The integro-differential model captures the dynamics of quantitative resistance, considering resistance as a continuous variable from fully sensitive to fully resistant. The second model, on the other hand, accounts for qualitative resistance by incorporating discrete genetic mutations. Both models consider key factors such as pesticide decay rates, fitness costs associated with resistance, and the impact of integrated pest management (IPM) strategies. Our findings highlight the critical role of fitness costs in delaying resistance development and demonstrate the enhanced effectiveness of IPM techniques over conventional chemical control. This dual-model approach provides a robust framework for designing sustainable pest management practices in agriculture
Antitutsismus und Antisemitismus: Verschwörungs- und Spionagemythen zu den Tutsi Ruandas in komparatistischer Perspektive
No full textInternational audienc
Charge Transfer Between Ce and Fe During Cooling of an Aluminosilicate Melt: An In Situ XANES Investigation
No full textInternational audienceMultivalent elements are often incorporated to silicate glasses to enhance specific properties to the final product. However, these properties strongly depend on the redox state of the multivalent elements. While the redox behavior of glasses containing a single multivalent element is well studied, research on the in situ interaction between multiple multivalent elements is scarce. In this study, in situ XANES spectroscopy was used to investigate the high temperature redox state of both Ce and Fe in an aluminosilicate melt. The results were compared to room temperature measurements. Our findings demonstrate that, at high temperature equilibrium, Ce and Fe act independently. However, upon cooling below 900°C, a charge transfer process occurs between the two elements as described by the reaction Ce4+ + Fe2+ → Ce3+ + Fe4+. The existence of such a charge transfer, observed even in melts doped with very low Ce and Fe amounts, could suggests that both elements are not randomly distributed in the melt. The intensity of the charge transfer process depends on the CeO2/FeO ratio, with the element present in excess showing minimal change in redox state upon cooling. This explains the difference of room temperature redox state between samples
The role of habitat mosaics on biological communities at hydrothermal vents and their periphery
No full textHydrothermal vent fields harbour a heterogeneous seascape owing to complex topography and vent fluid emissions, including in peripheral areas beyond active venting. At the Lucky Strike hydrothermal vent field, a remotely operated vehicle was used to acquire two hectares of seabed imagery to evaluate the role of environmental conditions on the structure and distribution of benthic communities. Our analyses revealed that large and mature edifices are potential keystone structures supporting hotspots of vent specialists (e.g., Bathymodiolus azoricus ) and associated fauna (e.g., Zoanthidae). Higher densities of mobile bathyal shrimps were found in slabs adjacent to active venting areas. Communities occupying areas with lower hydrothermal exposure displayed significantly higher diversity than areas located closer (≤ 40 m) to vent emissions. Between 40 and 120 m from active sites, community diversity was greatest on hard substrata dominated by sessile organisms—such as octocorals, Cladorhizid and Hexactinellid sponges—in greater densities when these substrates were composed of basalt with complex topography. While the gradient in hydrothermal exposure creates a spatial zonation of benthic communities, abundance and diversity patterns remain locally conditioned by seabed topography and substratum hardness. This interplay fosters a patchwork of faunal communities at the decametre scale. These results underscore the complexity of designing surveys encompassing the diversity of habitat conditions within the deep hydrothermal seascape. Although historically overlooked, the diversity of distinct benthic communities beyond venting zones emphasises the ecological significance and vulnerability of areas that could be targeted by mining
Graph neural networks for water level modelling in floodplains: application to the Severn floodplain with HydroGCN
No full textSéminaire invité dans le cadre d’un groupe de travail sur l’intelligence artificielle organisé au laboratoire IRPHÉ (Aix-Marseille Université) par Aurore Loisy
Island-wide molecular survey targeting Pseudocercospora spp. causing Sigatoka leaf spot diseases of banana in Mauritius
No full textInternational audienceThe Sigatoka disease complex, caused by Pseudocercospora fijiensis, P. musae, and P. eumusae, severely impacts banana production worldwide. Although all three species have been reported in Mauritius, their distribution across the island has not been assessed. In April 2024, surveys were conducted at 43 sites across the island, and species-specific real-time PCR assays were used for pathogen identification. P. eumusae was the predominant species, detected at all sites (88% prevalence). P. fijiensis occurred at lower frequency (11%) but was present in all regions, confirming its rapid expansion since its first detection in 2022. P. musae was rare (1%) and confined to three sites across three regions. Coexistence between P. eumusae and P. fijiensis was observed at eleven sites, while all three species co-occurred at three. These findings provide the first island-wide molecular assessment of three Pseudocercospora spp. in Mauritius and demonstrate the continuing spread of P. fijiensis, underscoring the need for sustained monitoring and management strategies