HAL Portal UPF (Université de la Polynésie française)
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Development of novel microsatellite marker sets for 5 common tropical hydrozoan species (Cnidaria: Hydrozoa) from the Southwestern Indian Ocean
No full textInternational audienceBackgroundIn the context of global change, coral reefs and their associated biodiversity are under threat. Several conservation strategies using population genetics have been explored to protect them. However, some components of this ecosystem are understudied, such as hydrozoans, an important class of benthic organisms worldwide. A comprehensive study of coral reefs as a whole is needed to develop effective conservation measures. Here we describe the development of 75 new microsatellite markers for 5 hydroid species: Antennella billardi, Lytocarpia phyteuma, Sertularella diaphana, Taxella gracilicaulis and Zygophylax rufa.Methods and resultsMarkers were tested on 246 specimens from Reunion and Mayotte islands in the southwestern Indian Ocean. Allelic diversity ranged from 1 to 21 for the 5 species, and 9 loci were estimated to have null allele frequencies ranging from 10 to 37%. Observed and expected heterozygosities ranged from 0.03 to 1 and from 0.03 to 0.93, respectively. 12 loci showed data significantly out of Hardy-Weinberg equilibrium. Cross-amplification was performed in 8 species, of which 3 showed high successful amplification rates (53 to 93%).ConclusionThe estimated genetic metrics were similar to those reported for other hydroid and cnidarian marker sets. Cross-amplification showed a contrasting transferability between species, often related to the hydroid phylogeny. These newly developed markers will be relevant to the study of hydroid population genetics and coral reef conservation
Introduction - Agriculture et urbanisation : dynamiques et enjeux des espaces périurbains
No full textInternational audienceGuy Burgel justifies the inclusion of a volume on peri-urban agriculture in the Villes en parallèle collection by pointing to a revolution in the identification status of the rural and the urban. Breaking with the equilibrium established since Neolithic times, is this not less ‘the end of the peasants’, as the sociologist Henri Mendras thought, than the end of the countryside?This volume presents the forms of peri-urban agriculture that play a key role in the history and development of cities. These agricultural areas, although integrated into production, respond to the expectations of city dwellers, regaining a landscape status. Peri-urban farmers are anticipating the inevitable urbanisation of their land, often by gradually relocating their activities. The issues of land security and mixed use raise challenges for modern urban management. This volume analyses these territorial recompositions, questioning the traditional boundaries between urban and rural in the era of the Anthropocene.Guy Burgel justifie l’accueil d’un volume sur les agricultures périurbaines dans la collection Villes en parallèle par une révolution dans le statut d’identification du rural et de l’urbain. Rompant avec les équilibres établis depuis le néolithique, n’est-ce pas moins « la fin des paysans », comme le pensait le sociologue Henri Mendras, que la fin des campagnes ?Le volume présente les formes d’agriculture périurbaine, jouant un rôle clé dans l'histoire et l'évolution des villes. Ces espaces agricoles, bien qu'intégrés à la production, répondent aux attentes citadines, retrouvant un statut paysager. Les agriculteurs périurbains anticipent l'urbanisation inévitable de leurs terres, souvent en délocalisant progressivement leurs activités. Les enjeux de la sécurisation foncière et la mixité des usages soulèvent des défis pour la gestion urbaine moderne. Ce volume analyse ces recompositions territoriales, questionnant les frontières traditionnelles entre l'urbain et le rural à l'ère de l'anthropocène
Lagrange's theorem for a family of finite flat group schemes over local Artin rings
No full textLet R be a local Artin ring with residue field k of positive characteristic. We prove that every finite flat group scheme over R whose special fiber belongs to a certain explicit family of non-commutative k-group schemes is killed by its order. This is achieved via a classification result which rely on the explicit study of the infinitesimal deformation theory for such non-commutative k-group schemes. The main result answers positively in a new case a question of Grothendieck in SGA 3 on whether all finite flat group schemes are killed by their order.</div
Censure des dispositions fiscales d'une loi du pays polynésienne rétroactive
No full textInternational audienceNote sous Conseil d'Etat, 28 juin 2024, no 493563 (sera mentionné aux tables du Lebon), Mouvement des entreprises de France Polynésie française et autre
Chemical toxicity of leachates from synthetic and natural-based spat collectors on the embryo-larval development of the pearl oyster, Pinctada margaritifera
No full textIn French Polynesia, the pearl farming industry relies entirely on collecting natural spat using a shade-mesh collector, which is reported to contribute to both plastic pollution and the release of toxic chemicals. With the aim of identifying more environment-friendly collectors, this study investigates the chemical toxicity of shade-mesh (SM) and alternative materials, including reusable plates (P), a newly developed biomaterial (BioM) and Coconut coir geotextile (Coco), on the embryo-larval development of Pinctada margaritifera. Embryos were exposed during 48 h to four concentrations (0, 0.1, 10 and 100 g L-1) of leachates produced from materials. Chemical screening of raw materials and leachates was performed to assess potential relationships with the toxicity observed on D-larvae development. Compared to the other tested materials, results demonstrated lower levels of chemical pollutants in BioM and no toxic effects of its leachates at 10 g L-1. No toxicity was observed at the lowest tested concentration (0.1 g L-1). These findings offer valuable insights for promoting safer spat collector alternatives such as BioM and contribute to the sustainable development of pearl farming
Fish communities can simultaneously contribute to nature and people across the world's tropical reefs
No full textInternational audienceAnthropogenic activities are eroding biodiversity and its contributions to nature and people worldwide. Yet, the dual imperative to protect nature and sustain human well-being raises potential trade-offs that remain to be quantified. Using standardized fish surveys across 1,237 tropical reefs worldwide, we converted the presence and abundance data of 1,024 species into 29 fish community contributions that primarily benefit either nature or people. We show that "Nature-for-Nature" contributions are mostly positively correlated to total fish biomass, while "Nature-for-People" contributions are more independent. Trade-offs among contributions are not the rule, with some tropical fish communities simultaneously providing high levels of different contributions. High mean contributions have been found in all tropical oceans, so sustaining healthy tropical reefs while promoting human well-being seems achievable within most countries, rather than mutually exclusive.Our framework offers an opportunity to explore different management strategies and pathways on tropical reefs between the use and sparing of nature, towards more favorable and sustainable ecological and social futures.</p
On the existence of analytic families of stable lattices in trianguline representations and their reductions
No full textInternational audienceIn this article, we prove the existence of rigid analytic families of G-stable lattices with locally constant reductions inside families of representations of a topologically compact group G, extending a result of Hellman obtained in the semi-simple residual case. Implementing this generalization in the context of Galois representations, we prove a local constancy result for reductions modulo prime powers of trianguline representations of generic dimension d. Moreover, we present two explicit applications. First, in dimension two, we extend to a prime power setting and to the whole rigid projective line a recent result of Bergdall, Levin and Liu concerning reductions of semi-stable representations of Gal(Q p /Qp) with fixed Hodge-Tate weights and large L-invariant. Second, in dimension d, let Vn be a sequence of crystalline representations converging in a certain geometric sense to a crystalline representation V . We show that for any refined version (V, σ) of V (or equivalently for any chosen triangulation of its attached (ϕ, Γ)-module Drig(V ) over the Robba ring), there exists a sequence of refinement σn of each of the Vn such that the limit as refined representations (Vn, σn) converges to the (V, σ). This result does not hold under the weaker assumption that Vn converges only uniformly p-adically to V (in the sense of Chenevier, Khare and Larsen)
