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Bridging the Gap Between Lagrangian and Eulerian Species Distribution Models for Abundance Estimation—A Simulation Experiment
No full textInternational audienceAim: In mobile species, individual movement decisions based on biotic and abiotic conditions determine how individuals interact with the environment, heterospecifics and conspecifics. Accordingly, these decisions underpin all ecological principles and structure broader spatial patterns at the population and species level. Species distribution models (SDMs) are therefore paramount in ecology, with implications for both fundamental and applied studies. There are many robust SDM techniques, from individual-scale (Lagrangian) to population-scale (Eulerian) models. Their outputs routinely support wildlife management, conservation, or risk assessments. Yet, it remains unclear whether SDMs built at individual and population scales infer the same processes, and whether the spatial distributions they predict are comparable. Here, we address this key question with a simulationexercise. Location: Virtual environment.Taxon: Virtual species.Methods: First, we simulated the individual movements of two highly mobile species, one central-place forager and one free ranger. Second, we surveyed the species at the individual-scale, replicating Lagrangian studies by tracking individual movements, and at the population-scale, replicating Eulerian surveys by censusing the study area with standardised protocols. The resulting data were analysed following well-establishedstatistical methods to assess species abundance distribution. We used Resource Selection Functions (RSFs) for Lagrangian data and Density Surface Models (DSMs) for Eulerian data.Results and Main Conclusions: Both Lagrangian and Eulerian SDMs adequately estimated the species' relationship with environmental conditions. Although some fine-scale differences occurred, both perspectives yielded highly correlated spatial distributions (correlations of 0.8–1.0 between pairs of models), and successfully predicted true abundance distributions (correlations of 0.6–0.7 with the true abundance distribution). Our results demonstrate that Lagrangian and Eulerian SDMs are statistically consistent and directly comparable, which is of great importance for conservation science. This provides crucial guidance for the combination of predictions from both model types to inform spatial planning within a wide range of management contexts
: Phonological Stability of Bimoraic Nouns from the Perspective of Frequency
No full textInternational audienceThis paper examines the phonological features of high-frequency nouns in two major Japanese linguistic corpora: the Balanced Corpus of Contemporary Written Japanese (BCCWJ) and the Corpus of Spontaneous Japanese (CSJ), both compiled by the National Institute for Japanese Language and Linguistics. The study focuses on word length and accent patterns, comparing the high-frequency noun data with overall corpus lexicons and dictionary entries. The key findings indicate that these nouns tend to consist of two morae and exhibit a final-accented pattern across both corpora. These results are consistent with previous evidence and research on the one-footed bimoraic structure observed in Japanese phonological phenomena (Kubozono 1995, Ito 1990, Labrune 2002, Poser 1990), further suggesting their phonological stability, autonomy, and conservation in the sense of by Bybee (2001, 2007)
Parental blood mercury levels are correlated, and predictive of those in eggs in a long-lived seabird
No full textInternational audienceMercury (Hg) is a pollutant that does not only biomagnify along the food chain, but can also accumulate in longlived top-predators, such as many seabirds, and be transferred to the next generation during reproduction. To better understand the transfer of Hg from parents to offspring, as well as its potential negative consequences, we used seven years of data on total mercury (THg) levels in the blood of common terns (Sterna hirundo) breeding at the German North Sea coast, and their eggs. We assessed whether (i) THg levels of pair members correlate, (ii) (changes in) parental THg levels correlate with those in their eggs, (iii) egg THg levels are repeatable within a given clutch and within parents across years, and (iv) parental and egg THg levels correlate with embryonic development, hatching success and hatch mass. Blood THg levels of pair members were positively correlated, but only maternal THg levels correlated with those in shells of hatched eggs, with within-individual increases over time leading to increases in shell THg levels as well. THg levels in shells of hatched eggs showed within-clutch and across-year repeatability. THg levels in shells of unhatched eggs were higher than those of hatched eggs, and were lower when embryos had developed for longer before they died, suggesting Hg absorption from the eggshell. THg levels in the contents of unhatched eggs were positively correlated with those of both parents. Interestingly, hatching success and hatch mass correlated positively, rather than negatively, with maternal THg levels, suggesting that a Hg-rich maternal diet (e.g., large fish or prey of high trophic levels) may enhance reproductive investment, thereby offsetting potential negative effects of Hg, at least under current pollution levels. Testing for downstream effects of transferred Hg on chicks will, however, be important
Review of thermal management of electronics and phase change materials
No full textInternational audienceEffective thermal management systems (TMS) are crucial for the optimal operation of electronic devices in computing, data centers, and transportation. This review begins by highlighting the essential role that TMS plays in today's electronics, where performance, reliability, and energy efficiency are of utmost importance. TMS strategies are vital for addressing the escalating thermal challenges associated with the ever-increasing computational demands of modern electronics. This study focuses on pivotal applications: mobile phones, laptops, data centers, electric vehicles and aircraft. Given the fast evolution of microelectronics technologies, research in electronics tends to improve compacity, significantly impacting their thermal behavior, a fact that has garnered scant attention. Device failures mainly occur when recommended temperature thresholds are exceeded. Current cooling solutions used to tackle this overheating consist of heat pipes and/or thermal drains (in most efficient cases, liquid-gas phase changes are involved), comprising assisted by noisy and energy consuming fans. Although this problem has been studied extensively for decades, no satisfactory solution has been found, and electronic component thermal management continues to be a major challenge. This work is an original contribution, and concludes that the development of innovative TMS based on hybrid materials (a metallic matrix with an optimized topology and whose microporosity is impregnated with phase change materials) could pave the way for a brand new generation of ambitious microelectronics technologies. The maximum tolerable temperature thresholds constitute the critical criteria for the targeted applications. The review makes PCM selections based on criteria such as latent heat, absence of undercooling, compatibility with metals
De « Chez les Sinn-Feiners » (1920) à Mary de Cork (1924), Joseph Kessel témoin de « L’Irlande révolutionnaire »
No full textInternational audienc
How does habitat use influence PFAS contamination in wildlife? Combining stable isotopes and GPS tracking in three gull species
No full textInternational audiencePer-and polyfluoroalkyl substances (PFAS) are toxic and persistent compounds widely distributed in the environment and accumulate in top predators, including seabirds. Because of the biomagnification potentials of some PFAS, diet is thought to be a key exposure route for PFAS. However, other factors, such as habitat use, may mask interspecific differences in PFAS exposure expected from trophic structure. Among seabirds, gulls are generalist that forage in both terrestrial and marine habitats, making them relevant models to concurrently investigate the influence of foraging habitats and trophic position on PFAS exposure. We combined plasma PFAS concentrations with GPS tracking and stable isotopes to define foraging habitats (δ 13 C; δ 34 S; GPS) and trophic positions (δ 15 N) in three sympatric gull species breeding in France (Isle of Ré). In herring gulls (Larus argentatus), long-chain perfluoroalkyl carboxylic (PFCAs) were positively correlated with high trophic resources from marine habitats. We found compound-and sex-dependent relationships between PFAS concentrations and stable isotope values in lesser black-backed gulls (Larus fuscus), while no association was found with habitat use. No association was found between PFAS levels and stable isotopes in great blackbacked gulls (Larus marinus). Our study suggests that coastal habitat could be a source of PFCA contamination and highlights that the influence of habitat use on gull exposure to PFAS varied depending on species, sex, and compounds.</div
Metabolomic fingerprint of Reynoutria japonica (Polygonaceae) using suspect screening with LC-HRMS and untargeted approach with GC-HRMS
No full textInternational audienceKnotweed (Reynoutria japonica) is an invasive plant whose ecological dominance in its invasive range may partly rely on allelopathic interactions mediated by root exudates and especially secondary metabolites of wide polarity range. To elucidate the chemical diversity of these exudates, a metabolomic strategy combining liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) and gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS) was employed. After optimization of EcoRoot methodology with design of experiment (DoE), root exudates were sampled with 3 different sorption materials and analyzed using LC-ESI-MS/MS and GC-HRMS. Molecular networking was applied to MS/MS data to visualize chemical structural similarities and facilitate the identification of metabolites with a confidence annotation scale. Diverse families of compounds, including flavonoids, alkaloids, organic acids, terpenoids, and phenolics, were annotated and many of which could be implicated in allelopathic interactions or rhizospheric communication. Notably, molecular networks highlighted the presence of lineage-specific metabolites (Polygonaceae). Also, suspect screening was performed and led to confirmation of allelochemicals as root exudates: chlorogenic acid, catechin, and polydatin. GC-HRMS further revealed volatile organic compounds such as terpenoids or carbon disulfide, which may contribute to belowground chemical interference. These VOCs were trapped using another sorbent called Sorb-Star (R) and then thermodesorbed. This study underscores the value of integrated HRMS-based metabolomics for exploring the chemical diversity of R. japonica and provides candidate metabolites (isomers of selinene, carbon disulfide) for future studies in both fundamental and applied ecology and agronomy. Finally, this study presents the first metabolomic fingerprint of R. japonica grown in soil
Concevoir un catalogue de recherche universitaire : intentions, enjeux et réalisations: Rapport d’activité du projet UCLRBilan 2022 – 2025
No full textThe UCLR project aims to structure, highlight, and pool the research products of La Rochelle Université in a spirit of open, interdisciplinary and territorial science. Designed as a digital infrastructure serving researchers, services, and local partners, UCLR helps to reference, document, and showcase diverse research products (data, models, digital tools...).This report traces the implementation of the project, after three years of funding and development, in a context of research practices transformation related to open science. Faced with the heterogeneity of uses, the diversity of disciplines, and the growing number of research products, the UCLR tool was designed as an institutional response aimed at structuring, sharing, and hightlighting these products at the scale of La Rochelle Université. Now that the first phase of funding has come to an end, the project has reached a significant level of maturity: the platform is operational, maintained, and already sustained. The report thus marks the end of the start-up phase and opens up the challenges of consolidation, community building, and longer-term planning. UCLR currently appears to be an infrastructure that will thrive through its uses, collective commitment, and lasting anchoring in the institution's scientific and local governance policy.Le projet UCLR vise à structurer, valoriser et mutualiser les produits de recherche de La Rochelle Université dans une logique de science ouverte, interdisciplinaire et territorialisée. Pensé comme une infrastructure numérique au service des chercheurs, des services d'appui et des partenaires du territoire, UCLR permet de référencer, documenter et rendre visibles des produits de recherche hétérogènes (données, modèles, outils numériques…).Ce rapport retrace la mise en oeuvre du projet, après trois années de financement et de développement, dans un contexte de transformation des pratiques de recherche liées à la science ouverte. Face à l'hétérogénéité des usages, à la diversité des disciplines et à la multiplication des produits de recherche l'outil UCLR a été conçu comme une réponse institutionnelle visant à structurer, mutualiser et valoriser ces productions à l'échelle de La Rochelle Université.Arrivé à la fin d'une première phase de financement, le projet a atteint un niveau de maturité significatif : la plateforme est opérationnelle, maintenue et déjà alimentée. Le rapport marque ainsi la clôture d'une phase d'amorçage et ouvre sur les enjeux de consolidation, de fédération des communautés et de projection à plus long terme.UCLR apparaît désormais comme une infrastructure appelée à vivre par ses usages, par l'engagement collectif et par son ancrage durable dans la politique scientifique et territoriale de l'établissement.</div
Dynamics of Infragravity Waves Across the Southern Reef Barrier of Mayotte, Indian Ocean
No full textInternational audienceDue to climate change, tropical islands are being increasingly exposed to coastal hazards. Under energetic incident swells, infragravity (IG) waves can have a key contribution to extreme water levels and flooding, but their dynamics at barrier reef remains little studied. In this context, this study analyses IG wave generation mechanisms and transformations across a barrier reef to the southwest of Mayotte (Indian Ocean), combining a new comprehensive field dataset with phase resolving wave modelling. This analysis reveals that IG waves are mostly breakpoint-forced and suffer a substantial dissipation by bottom friction, particularly at low tide. Numerical experiments with reduced bottom friction representing a degraded coral reef suggest that IG waves would grow by about 20% across the reef at high tide. This study highlights the key role of coral reefs to dissipate IG waves and hence limit extreme water levels and subsequent coastal hazards.</div
