Portail "HAL-Francophonie Afrique et Océan Indien"
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La distribution des champignons mycorhiziens sur les écorces d'arbres corrèle avec la préférence d'hôte de l'orchidée épiphyte tropicale Bulbophyllum variegatum sur l'île de La Réunion
No full textInternational audienceWhile host preference of tropical epiphytic plants is mainly driven by tree abundance and size, the distribution of mycorrhizal fungi among tree species is likely to influence host preference in orchids. Here, we investigated the host preference of ten epiphytic orchids in a one-hectare forest plot in La Réunion, revealing a strong preference in the orchid Bulbophyllum varigatum.Using an Illumina sequencing of the ITS-2 barcode of fungi, we identified fungal communities, including mycorrhizal Tulasnellaceae, both in the bark of host tree species in the area and in the roots of B. variegatum across the island. Bark-dwelling fungal and mycorrhizal communities varied between tree species, with fungal OTUs being specific to the host of B. variegatum. Three of them (one Serendipitaceae and two Tulasnellaceae) were found to be mycorrhizal at different stages of the orchid's life cycle. Our results suggest that the uneven distribution of mycorrhizal fungi between tree barks could influence the host preference of epiphytic orchids, a hypothesis that will require experimental testing.Alors que la préférence d'hôte des plantes épiphytes tropicales dépend principalement de l'abondance et de la taille des arbres, la répartition des champignons mycorhiziens sur les différentes espèces d'arbres est susceptible d'influencer celle des orchidées . Dans cette étude, nous avons étudié la préférence d'hôte de dix orchidées épiphytes dans une parcelle forestière d'un hectare à La Réunion, révélant une forte préférence d'hôte chez l'orchidée Bulbophyllum varigatum. À l'aide d'un séquençage Illumina du code-barre fongique ITS-2, nous avons identifié les communautés fongiques, notamment les Tulasnellaceae mycorhiziens, à la fois dans l'écorce des espèces d'arbres hôtes de la région et dans les racines de B. variegatum à travers l'île. Les communautés fongiques et mycorhiziennes vivant dans l'écorce varient selon les espèces d'arbres, certaines OTUs fongiques étant spécifiques à l'hôte B. variegatum. Trois d'entre elles (un Serendipitaceae et deux Tulasnellaceae) se sont avérées mycorhiziennes à différents stades du cycle de vie de l'orchidée. Nos résultats suggèrent que la répartition inégale des champignons mycorhiziens entre les écorces des arbres pourrait influencer la préférence d'hôte des orchidées épiphytes, une hypothèse qui devra être vérifiée expérimentalement
Benchmarking Large Language Models on Floating-Point Error Classification
No full textThis paper investigates the capability of Large Language Models (LLMs) to detect and classify floating-point errors statically in software code. We introduce InterFLOPBench, a benchmark of 90 C kernels with 1 130 test samples designed to evaluate LLMs across six categories of floating-point error: cancellation, comparison, division by zero, overflow, underflow and NaN, compared across 14 LLMs. The evaluation framework treats floating-point error detection as a multi-label classification problem and employs the F1-score metric to measure performance. Results demonstrate that latest models (Qwen 3 32b, Gemini 2.5 Flash, Phi 4 Reasoning, DeepSeek R1T2, and gpt-oss 20b and 120b) achieve a performance greater than 0.88 overall F1-score. Performance varies between error categories, between explicit operations such as division by zero (Average F1-score: 0.8479) and more subtle numerical phenomena such as underflow (Average F1-score: 0.6059) and cancellation (Average F1-score: 0.6164)
A new M θ and A θ fractional-integrals for crack initiation and mixed modes growth in hygro-viscoelastic orthotropic materials
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Bastardía y filiación comunitaria en Sanchiu (2021) de Dina Ananco. Perspectiva decolonial en la poesía de la Amazonía peruana
No full textInternational audienceEn este artículo se intenta mostrar cómo la poesía desarticula la propia noción de indígena amazónico en tanto construcción colonial. Este sujeto ha sido material y simbólicamente exotizado e identificado con un territorio codiciado y expoliado por sus recursos naturales. El discurso poético que aquí se analiza se coloca dentro de la piel de una “indígena amazónica” de la nación wampis que no acepta, sin embargo, esta única posición y deconstruye su supuesta identidad “originaria”. Como resultado de este proceso, se acerca más bien a la noción de bastardía propuesta por María Galindo, es decir, a la construcción de un sujeto que se inventa a sí mismo para liberarse de la secuencia de dominación y opresión. Este sujeto femenino en tránsito se ancla a un saber femenino comunitario como fuente incesante de conocimiento
Zika Virus Persists in Retinal Pigment Epithelial Cells Resulting in Moderate Cytopathic Effects but Epithelial-Mesenchymal Transition
No full textInternational audienceThe Zika virus (ZIKV), a pathogenic member of the orthoflavivirus family, is raising serious health concerns worldwide. Like Dengue (DENV) and Chikungunya (CHIKV) viruses, it is one of the arboviruses that poses an emerging threat to areas where its main vectors, Aedes mosquitoes, proliferate, well beyond tropical and subtropical regions. Although often asymptomatic or mild, ZIKV infection has been responsible for a worrying increase in serious congenital syndromes, including microcephaly. The ability of ZIKV to be transmitted sexually and its long persistence in body fluids suggests its incomplete clearance in particular tissues, linked to recurrent infection. Among its clinical presentations, ZIKV infection has been associated with ocular complications, including maculopathy, retinopathy, uveitis, and optic neuropathy, which can lead to lasting visual impairment. The blood-retinal barrier (BRB), primarily composed of retinal pigment epithelium (RPE) and endothelial cells, plays a crucial role in shielding the retina from pathogens. Its disruption has been linked to viral retinal infections. In vitro monitoring of infection on hTERT RPE-1 cells revealed an ability of ZIKV to persist for up to 30 days in nearly 10% of the cells. This prolonged infection was marked by moderate cytopathic effects and notable morphological changes throughout the cell layer, suggestive of an epithelial-mesenchymal transition (EMT). Long-lasting viral replication and production were associated with reduced expression of epithelial genes and increased expression of certain mesenchymal genes, suggesting that the integrity of the RPE layer may be compromised. These results indicate that viral persistence and phenotypic transition observed in vitro in RPE cells could provide clues to understanding the late onset of ocular pathophysiological manifestations in Zika virus-related diseases
Exploring factors affecting malaria vaccination intention and COVID-19 vaccine uptake: evidence from a joint analysis in rural Senegal
No full textInternational audienceBackground: Current malaria vaccination efforts target infants from 5 months of age; however, adult malaria mortality remains a significant and under-reported issue in high-transmission settings. Concerns are emerging that COVID-19-related vaccine hesitancy may extend to upcoming vaccines, including hypothetical ones such as a malaria vaccine for adults. This study investigates both shared and vaccine-specific determinants of malaria vaccination intention, comparing them with those influencing COVID-19 vaccine uptake.Methods: A cross-sectional telephone survey was conducted in 2023 among 795 adults residing in the rural area of Niakhar, Senegal. The Health Belief Model served as the analytical framework to identify determinants of vaccination behaviours and intentions. A multivariable bivariate probit model was used to jointly assess factors associated with favourable intentions to receive a hypothetical adult malaria vaccine and actual uptake of the COVID-19 vaccine.Results: Among surveyed participants, 35.6% had received at least one dose of a COVID-19 vaccine, and 58.6% expressed favourable intentions to receive a malaria vaccine, assuming it were available and free of charge. COVID-19vaccinated individuals were 60% (p < 0.001) more likely to report favourable intentions to receive a malaria vaccine.In the multivariable probit model, perceived disease severity was more strongly associated with COVID-19 vaccine uptake, whereas perceived disease susceptibility more strongly predicted favourable intentions to receive a malaria vaccine. Women were more likely to support malaria vaccination (p = 0.005), while adults aged 59 years and older had higher rates of COVID-19 vaccination (p < 0.001).Conclusions: These findings suggest that although some determinants are vaccine-specific, most are shared across vaccines. The results offer actionable insights to guide future malaria vaccination strategies. Further research in urban settings and across diverse countries is warranted to enhance understanding of cross-vaccine perceptions and to inform targeted communication efforts.</p
Prevalence of antimalarial drug resistance molecular markers in Makenene, central Cameroon
No full textInternational audienceBackground: Antimalarial drug resistance remains a significant challenge in the fight against malaria in Cameroon. Given the high prevalence of malaria in Makenene in central Cameroon and the limited knowledge of drug resistance profiles in the area, the prevalence of Plasmodium falciparum drug resistance genetic markers was assessed. Methods: 185 samples from asymptomatic individuals with P. falciparum parasitaemia collected between September and October 2021 were sequenced for the Pfdhfr, Pfdhps, Pfcrt, Pfmdr1, and PfK13 genes. Results: One hundred percent of the samples harboured parasites with triple mutant Pfdhfr I 51 R 59 N 108 I 164 (IRNI), associated with high level of resistance to pyrimethamine. The septuple mutant Pfdhfr IRNI and Pfdhps A 436 G 437 K 540 G 581 S 613 (AGKGS), associated with resistance to sulfadoxine-pyrimethamine, was detected in 62.0 % of the isolates. The new Pfdhps I431V mutation was observed in 18.8 %. The octuple mutant IRNI + VAGKGS haplotype, overrepresented in pregnant women taking intermittent preventive treatment with sulfadoxinepyrimethamine, was found in 17.4 %. The Pfdhps K540E mutation, linked to "super" resistance to sulfadoxine, was only detected in 1.9 %. The Pfcrt C 72 V 73 I 74 E 75 T 76 haplotype, implicated in chloroquine resistance, was absent in Makenene. The Pfmdr1 N 86 F 184 haplotype, selected in parasites with a recrudescence in patients treated with artemether-lumefantrine, was found in 73.2 %. No isolate harboured the Y 86 Y 184 haplotype, selected in parasites with recrudescence in patient treated with dihydroartemisinin-piperaquine. Moreover, no mutation associated with artemisinin partial resistance was detected in PfK13. Conclusions: The in-depth analysis of genetic mutations associated with antimalarials resistance in this study, notably those with a high prevalence of mutations on the Pfdhfr and Pfdhps genes, highlights the immediate need for proactive strategies to combat resistance in Makenene. Continuous monitoring, including molecular and in vivo surveillance is crucial to uphold the effectiveness of current treatments and, more particularly, artemisininbased combination therapies, and to enable better decision-making on effective treatment policy in Cameroon and in Africa as a whole.</div
Choisir une école musulmane sous contrat à La Réunion : valeurs parentales, logiques professionnelles et rapport à la laïcité
No full textInternational audienceUne analyse sociologique de l’enseignement privé musulman sous contrat à partir du cas singulier de la Médersa de Saint-Denis à La Réunion est proposée. En se décentrant du cadre hexagonal, l’étude met en évidence une régulation localisée de l’islam scolaire, façonnée par l’histoire coloniale, le pluralisme religieux et une laïcité « créolisée ». Le choix parental d’une école musulmane sous contrat repose sur la recherche d’un équilibre entre exigences scolaires, cohérence religieuse et conformité laïque. L’enquête révèle un fonctionnement fondé sur des compromis pragmatiques, une hybridation des normes civiques et confessionnelles, et des ajustements quotidiens dans la gestion des rituels, des savoirs et de la diversité interne. En effet, des situations ordinaires de classe interrogent les formes contemporaines de coexistence entre régimes de vérité, y compris dans un contexte où les pluralismes convictionnels sont marqués par la circulation de discours relevant parfois d’une logique « post-vérité ». Contrairement au contexte hexagonal, le choix d’une école musulmane sous contrat à La Réunion peut être formulé sur un mode relativement ordinaire, comme un arbitrage éducatif inscrit dans l’offre scolaire locale
New planthoppers (Hemiptera: Cixiidae) from Madagascar support the establishment of a new genus, the revised status of Eumyndus perinetensis, and an updated molecular phylogeny of Malagasy Oecleini
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616204/) * Autres projets (id;sigle;titre): 2018/30/E/ NZ8/00880;;(USA) The evolutionary dynamics of the symbioses of Auchenorrhyncha// ;Epibio-OI II;(FRA) EPIdémiosurveillance et BIOcontrôle dans l'Océan Indien//International audienceRecent survey efforts in Madagascar have focused on the tribe Oecleini in the planthopper family Cixiidae due to an interest in identifying vectors of palm lethal decline phytoplasmas. During these surveys, planthoppers were collected on palms in natural habitats that were determined to represent a new genus, Geminimyndus gen. nov. Herein, two new species are described, G. spinaparum sp. nov. and G. spinamagnus sp. nov. Eumyndus perinetensis Synave is transferred to Geminimyndus gen. nov. as Geminimyndus perinetensis, comb. nov. Supplemental molecular data for the cytochrome c oxidase subunit I, histone 3, 18S rRNA and 28S rRNA are provided to support the establishment of the new genus and the transfer of E. perinetensis to the new genus.Les efforts récents de prospection à Madagascar se sont concentrés sur la tribu Oecleini de la famille des fulgoromorphes Cixiidae en raison de l'intérêt porté à l'identification des vecteurs du phytoplasme du dépérissement létal des palmiers possible par les espèces de ce groupe taxonomique. Au cours de ces prospections, des cixiides ont été collectées sur des palmiers dans des habitats naturels et il a été déterminé qu'elles représentaient un nouveau genre, Geminimyndus gen. nov. Deux nouvelles espèces sont décrites ici, G. spinaparum sp. nov. et G. spinamagnus sp. nov. et Eumyndus perinetensis est transféré dans ce nouveau genre. Des données moléculaires supplémentaires pour la sous-unité I de la cytochrome c oxydase, l'histone 3, l'ARNr 18S et l'ARNr 28S sont fournies pour étayer l'établissement du nouveau genre et le transfert d'E. perinetensis vers le nouveau genre
Combinatorial and algorithmic analysis of oriented hierarchies in statistical implicative analysis
No full textInternational audienceThis paper introduces a novel and more efficient method for constructing oriented hierarchies within the framework of Statistical Implicative Analysis. The primary focus of this study is the computational complexity of the original algorithm proposed by Gras, whose cubic time complexity is established in this work. To address this limitation, a detailed combinatorial analysis of hierarchical structures is performed, leveraging tools from analytic combinatorics. This methodology facilitates the enumeration of the number of possible configurations as a function of input size and enables the investigation of both the depth and width characteristics of the hierarchy’s block structure. This study then proposes a reconstruction algorithm based on a formal correspondence between the statistical implication graph and the oriented hierarchy. The proposed method achieves quadratic worst-case complexity, thereby resulting in a substantial improvement in computational performance. Moreover, the analytic framework also makes it possible to characterise the average-case behaviour of the algorithm. The findings of the comparative computational experiments demonstrate the clear advantage of the proposed method over Gras’s algorithm, both in terms of execution time and overall algorithmic efficiency