Unlocking research on rhizodeposition: a step-by-step guide for producing, sampling and analyzing

Rhizodeposits, i.e. the organic materials released by living roots into the soil, play a major role in plant interactions with their biotic and abiotic environment. However, our understanding of rhizodeposition processes has remained limited due to the methodological challenges associated with the collection and analysis of rhizodeposits. Here, we aimed to synthesize knowledge from the various fields of expertise required for studying rhizodeposition, in order to support the scientific community in making informed methodological choices and to ensure the robustness and comparability of studies. In particular, we developed an open-access decision support tool (CARROT: Collecting and Analyzing Rhizodeposits: Reviewing and Optimizing Tool), using existing literature and practical expertise from the interdisciplinary network RhizosPHARE. This tool has been designed to help newcomers and specialists in the field i) to quickly identify the most appropriate methodological option(s) in terms of plant growth conditions, sample collection and sample analysis according to their scientific question and their experimental constraints, ii) to get practical recommendation about each method, and iii) to get a direct access to additional information and references. As part of these guidelines, we also suggest a standardized protocol for collecting root exudates from hydroponically grown plants to characterize their composition. Together with the CARROT tool, this protocol paves the way towards establishing consistent, standardized methods for characterizing rhizodeposition and its impact in the plant-soil system

MultimodalBirds

MultimodalBirds: A Multimodal Image–Audio Dataset for Bird Species Classification.MultimodalBirds: A Multimodal Image–Audio Dataset for Bird Species Classification.MultimodalBirds is a dataset for bird species classification and multimodal learning. It combines bird images from a curated subset of iNaturalist 2021 with bird vocalizations from the Xeno-Canto Bird Recordings Extended dataset by matching species information.The resulting dataset provides aligned image–audio pairs and supports research on multimodal fusion, modality imbalance, class imbalance, and model scalability. The dataset is provied in three versions for ease of use: unbalanced, regular and tiny

Taxonomic characterization and toxicity assessment of strains of Gambierdiscus belizeanus from Seychelles, southwestern Indian Ocean

International audienceBenthic dinoflagellates associated with human ciguatera poisoning are present in the Indian Ocean and species such as Fukuyoa (formerly Gambierdiscus) yasumotoi, G. toxicus and G. belizeanus have been reported since the mid 90s. Even though, very little information is available concerning the occurrence of Gambierdiscus species and toxicity in the Seychelles waters. This study investigates four Gambierdiscus belizeanus strains isolated from Seychelles, focusing on their morphological and genetic characterization, as well as their potential for neurotoxin production. Water samples were collected in Bay Ternay (West Mahé) and around Saint Anne Island. Culture aliquots were fixed for species identification using microscopy and molecular tools (sequencing of D1-D3 and D8-D10 of LSU rDNA) and toxin production analyzed in a 21-day culture using the N2A bioassay. This revealed detectable low CTX activity in only one of the four strains, estimated to 1.7 fg CTX3C equiv/cell, while the other strains were non-cytotoxic. These findings represent the first molecular and toxicological characterization of G. belizeanus strains from the Seychelles, contributing to the understanding of ciguatera poisoning risks in the Indian Ocean and highlighting the variable toxin production capacity within Gambierdiscus species. Expanding this project to areas with high ciguatera occurrence in the Indian Ocean could help in characterizing the responsible toxins

A unified study of nuclear physics and dark matter constraints through gravitational-wave observations of binary neutron star mergers

International audienceUnderstanding the properties of strongly interacting matter at extreme densities is a central problem in fundamental physics, but neutron star mergers provide a natural laboratory for probing this regime. However, the complexity of the merger process complicates the interpretation of the associated gravitational-wave and electromagnetic signals. This picture becomes even more complex in the potential scenario in which dark matter accumulates around and in neutron stars, altering their structure and the associated observables. In this work, we study synthetic gravitational-wave observations of binary neutron star mergers with next-generation detectors, investigating their potential to extract both nuclear physics and dark-matter constraints. We also examine how the potential presence of fermionic, non-interacting dark matter inside neutron stars affects the inference of nuclear empirical parameters. We find that combining observations can tighten constraints on nuclear empirical parameters. However, the inferred values remain sensitive to systematic modeling biases and intrinsic degeneracies among the parameters. Conversely, our analysis reveals that even in the presence of dark matter, it will be unlikely to find decisive evidence for dark matter when analyzing gravitational-wave signals. Consequently, systematic biases in nuclear empirical parameter inference potentially resulting from the presence of dark matter are expected to be negligible even for observations with next-generation gravitational-wave detectors

Improving preemptive relaxation-based filtering for flowtime minimization in single machine scheduling

International audienceImproving preemptive relaxation-based filtering for flowtime minimization in single machine schedulin

Expériences de discrimination : entre indicibilité et conditions d’énonciation

International audienceAlthough the number of studies on discrimination experiences and, more recently, on individuals' reactions to these experiences has increased over the last two decades, few studies have focused on what makes individuals talk or not about their experience(s), particularly in a context of minimising ethno-racial discrimination. The question raised in this article is thus: what are the relevant elements, i.e. the "ingredients", linked to the life course, the characteristics of the experience, the contexts and the situations, that can help to say or not to say the experience of discrimination? The article is based on qualitative interviews conducted with young adults belonging to so-called "visible" minorities, mainly students. The article highlights the importance of proof, the seriousness of the act, the legitimating body and the mastery of vocabulary as conditions for the enunciation of the discriminatory experience, as well as the role played by homophily in the choice of people to whom it is possible to talk about it, without risking the accusation of paranoia. It is also because discrimination necessarily implies an act, that the word "racism" is more easily mobilized to speak about the experiences of stigmatization lived in everyday life. Finally, being born in France exposes one more to the feeling of discrimination and, at different times in one's life, one's parents' attitude towards France can also contribute to concealing these feelings.Aunque en las dos últimas décadas han proliferado los trabajos sobre experiencias de discriminación y, más recientemente, sobre las reacciones de las personas ante estas experiencias, son menos los estudios que han analizado qué hace que las personas hablen o no de sus experiencias, especialmente en un contexto en el que la discriminación etnorracial es políticamente invisible. Este artículo examina los elementos relevantes, es decir, los "ingredientes", relacionados con los antecedentes, las características de la experiencia, los contextos y las situaciones, que pueden hacer que la experiencia discriminatoria sea descriptible o indecible. Basándose en un estudio de entrevistas con jóvenes adultos pertenecientes a minorías denominadas "visibles", la mayoría de ellos estudiantes, este artículo destaca la importancia de las pruebas, la gravedad del acto, la autoridad legitimadora y el dominio del vocabulario como condiciones para hablar de la experiencia discriminatoria, así como el papel que desempeña la homofilia en la elección de las personas con las que es posible hablar de ella, sin arriesgarse a la acusación de paranoia. También porque la discriminación implica necesariamente un acto, la palabra "racismo" se utiliza más fácilmente para hablar de experiencias de estigmatización en la vida cotidiana. Por último, haber nacido en Francia aumenta las probabilidades de sentirse discriminado en distintos momentos de la vida, y la actitud de los padres hacia Francia también puede contribuir a ocultar estos sentimientos.Si les travaux sur les expériences de discriminations et, plus récemment, sur les réactions des individus face à ces expériences se sont multipliés durant les deux dernières décennies, plus rares sont ceux qui se sont intéressés à ce qui fait que les individus vont parler ou non de leurs expériences, d’autant plus dans un contexte d’invisibilisation politique des discriminations ethno-raciales. Cet article examine les éléments pertinents, c’est-à-dire les « ingrédients », liés au parcours, aux caractéristiques de l’expérience, aux contextes et aux situations, pouvant rendre dicible ou indicible l’expérience discriminatoire. S’appuyant sur une enquête par entretiens menés auprès de jeunes adultes appartenant à des minorités dites « visibles », étudiant·es pour la plupart, cet article met en évidence l’importance de la preuve, de la gravité de l’acte, de l’instance de légitimation et de la maîtrise du vocabulaire comme conditions à l’énonciation de l’expérience discriminante, ainsi que le rôle joué par l’homophilie dans le choix des personnes auxquelles il est possible d’en parler, sans risquer l’accusation de paranoïa. C’est aussi parce que la discrimination implique nécessairement un acte, que le mot « racisme » est plus facilement mobilisé pour parler des expériences de stigmatisation vécues au quotidien. Enfin, être né en France expose davantage aux ressentis des discriminations, à différents moments du parcours, la posture des parents vis-à-vis de la France peut également participer à taire ces ressentis

Tree Pólya Splitting distributions for multivariate count data

International audienceIn this article, we develop a new class of multivariate distributions adapted for count data, called Tree Pólya Splitting. This class results from the combination of a univariate distribution and singular multivariate distributions along a fixed partition tree. Known distributions, including the Dirichlet-multinomial, the generalized Dirichlet-multinomial and the Dirichlet-tree multinomial, are particular cases within this class. As we will demonstrate, these distributions are flexible, allowing for the modeling of complex dependence structures (positive, negative, or null) at the observation level. Specifically, we present the theoretical properties of Tree Pólya Splitting distributions by focusing primarily on marginal distributions, factorial moments, and dependence structures (covariance and correlations). A dataset of abundance of Trichoptera is used, on one hand, as a benchmark to illustrate the theoretical properties developed in this article, and on the other hand, to demonstrate the interest of these types of models, notably by comparing them to other approaches for fitting multivariate data, such as the Poisson-lognormal model in ecology or singular multivariate distributions used in microbiome

Two sides of Greek-Turkish language contact: A preliminary psycholinguistic investigation of word order variation in Istanbul Greek and Rhodian Turkish: Abstracts from , Université Côte d'Azur, Nice

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The ALPINE-CRISTAL-JWST Survey: Stellar and Nebular Dust Attenuation of Main-sequence Galaxies at <i>z</i> ∼ 4–6

International audienceCharacterizing dust attenuation is crucial for revealing the intrinsic physical properties of galaxies. We present an analysis of dust attenuation in 18 spectroscopically confirmed star-forming main-sequence galaxies at z = 4.4-5.7 observed with JWST/NIRSpec IFU and NIRCam, selected from the ALPINE and CRISTAL ALMA large programs. We fit the emission-line fluxes from NIRSpec and the broadband photometry from NIRCam with PROSPECTOR, using both spatially integrated emission and ∼0.6 kpc pixel-by-pixel measurements. We derive the stellar-to-nebular dust attenuation ratio ( f = E(B -V ) star /E(B -V ) neb ) from the SED fits and the Balmer decrement with Hα and Hβ. Although individual galaxies show large scatter, the best-fit value is f 0.51 0.03 0.04 = + , slightly higher than that measured for local starburst galaxies. We find weak correlations of f with galaxy properties, increasing with higher specific star formation rates, younger stellar ages, and more recent star formation. For the range of E(B -V ) star = 0.009-0.15 mag for in our sample, assuming f = 1 (often adopted in high-redshift studies) instead of f = 0.51 leads to the underestimation of line luminosities and ionizing photon production efficiency ξ ion by ∼3%-36% and ∼4%-46%, respectively. Finally, total stellar masses estimated from spatially integrated SED fits with delayed-τ star formation histories are systematically smaller than the sums of pixel-by-pixel SED fits by a median of ∼0.26 dex, likely because the integrated fits are biased toward luminous young stellar populations.</div

Genomic determinants of Bacillus cereus and outcomes of infection in preterm neonates: a multicentre retrospective study

International audienceObjectives: Bacillus cereus sensu lato (s.l.) or B. cereus group increasingly causes severe infections in preterm neonates. However, species-level identification and virulence characterization remain limited. This study aimed to identify B. cereus group species responsible for invasive infections in preterm neonates and to correlate genomic virulence profiles with clinical outcomes.Methods: We conducted a retrospective, multicentre study across 13 French hospitals (2010-2021), including 40 B. cereus group isolates from blood or cerebrospinal fluid of preterm neonates with invasive infections. Clinical data were extracted from patient records. Whole-genome sequencing (WGS) (Illumina and Oxford Nanopore) with hybrid assemblies enabled species identification using digital DNA-DNA hybridization and average nucleotide identity. Virulence genes were screened against a curated database of 65 virulence genes, and associations with clinical outcomes were analysed.Results: Forty isolates were analysed, 42.5% (17 of 40) of patients developed septic shock, and 37.5% (15 of 40), died, usually after rapid clinical deterioration. WGS identified seven species, predominantly Bacillus paranthracis (47.5%, 19 of 40) and B. cereus sensu stricto (20%, 8 of 40). Virulence gene content varied by species. The presence of hblCDAB (60%, 9 of 15), nprB (46.5%, 7 of 15), asbABCDEF (80%, 12 of 15), and essC-cereus/esxA (66.7%, 10 of 15) genes correlated with mortality (p 0.00015, 0.002, 0.0027, and 0.02, respectively). B. cereus sensu stricto carried more virulence determinants and was associated with higher mortality than B. paranthracis and other species, at day 7 (p 0.05) and at day 28 (p 0.0065). The cesH gene (60%, 15 of 25) is significantly associated with survival (p 0.007), particularly with B. paranthacis, the predominant species in our cohort.Conclusions: Invasive B. cereus group infections in preterm neonates are associated with high mortality, particularly in cases due to B. cereus sensu stricto. WGS enables precise species identification and virulence profiling, which are essential insights for diagnostic refinement, outbreak control, and risk stratification in neonatal intensive care settings