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Innovation low-cost et open source : l’exemple d’un nouvel outil de monitoring de la ressource en eau dans les marais littoraux
No full textInternational audiencePrecise monitoring of water levels in marshland wetlands is crucial for reconciling agropastoral activities with biodiversity and developing hydraulic management strategies. Innovations using low-cost technologies hold promise for equipping these territories, which require a dense network of measurement points. A tool, developed at experimental sites along the Atlantic coast, uses simple materials and a geolocated, opensource data acquisition technology, providing real-time monitoring that is easily deployable, robust, and reproducible. It is at the heart of developing a management plan involving a representative collective from the various marshland users. It represents a major opportunity for large-scale instrumentation to better understand the hydrological regimes underlying the functions provided by marshland wetlands. The analysis of this low-cost and open-source innovation raises broader questions about innovation in the management of a common good such as water.Le suivi précis des niveaux dans les zones humides de marais est crucial pour concilier les activités agropastorales et la biodiversité et construire des stratégies de gestion hydraulique. Les innovations mobilisant des technologies à bas coût sont prometteuses pour équiper ces territoires qui nécessitent un réseau dense de points de mesure. L’article étudie un outil expérimenté sur deux marais du littoral atlantique. Utilisant des matériaux simples et une technologie d’acquisition de données géolocalisées, libre et ouverte, il offre un suivi en temps réel, facilement déployable, robuste et reproductible. Il est au cœur de la construction d’un plan de gestion embarquant un collectif représentatif des différents usages du marais et il constitue une opportunité d’instrumentation massive pour mieux comprendre les régimes hydriques sous-jacents aux fonctions des marais. L’analyse de cette innovation low cost et open source questionne plus largement les travaux sur l’innovation dans la gestion d’un bien commun comme l’eau. Codes JEL : Q550, Q570, Q250, Q28
Telomere length decreases with age and reflects early-life environment but not adult condition in a long-lived migratory bird
No full textInternational audienc
Physiological and behavioural responses of wandering albatross chicks (Diomedea exulans) to novel and non-novel predators
No full textInternational audienceIn long-standing predator-prey systems, prey typically evolve costly responses to predation risk. How prey respond to novel predators is less investigated. We explored physiological (corticosterone, triglyceride), morphological (body condition) and behavioural (defensive posture) responses of wandering albatross (Diomedea exulans) chicks to a novel predator, the feral cat (Felis catus) in Kerguelen archipelago. We implemented a semi-experimental design to increase the variance in cat abundance by regulating cat populations in certain zones of the study colony. The aforementioned chick traits were then monitored and analysed at the zone scale, by comparing nests located within regulated and non-regulated zones, and at the nest scale, by recording cat abundance through intensive camera traps monitoring. This fine-scale approach further enabled us to investigate how chicks responded to southern giant petrels (Macronectes giganteus), an opportunistic predator-scavenger that has co-evolved with albatrosses. Cat abundances had no effect on chick traits. In contrast, higher abundances of giant petrel were associated with an elevated rate of corticosterone increase and lower triglyceride levels. In accordance with these results suggesting a more accurate perception of predation risk mediated by giant petrels than by cats, chicks were more prone to display a defensive posture when facing a giant petrel than a cat. We discuss these results in the light of contrasting evolutionary histories and predation patterns between albatrosses and their predators, and we emphasise that studies of predator impacts on prey populations must consider both the direct and indirect effects of all predators, as well as their interactions
Effects of lateral hydrological connectivity on the taxonomic and functional structure of fish communities in Saône river floodplains (France): implications for non‐native species distribution.
No full textInternational audienceLarge alluvial plain rivers provide a complex mosaic of freshwater habitats characterised by a lateral hydrological connectivity (LHC) gradient between the main channel and floodplains. This connectivity plays a key role in structuring aquatic communities, influencing species distribution, diversity, and ecosystem processes. The aims of our study were to assess the effects of the LHC gradient on both fish taxonomic and functional diversity, and to characterise the effects of this connectivity on the distribution of non‐native species. Community data were gathered through electrofishing at five sites in the main channel of the Saône River (France), and in four permanently (parapotamic) and four occasionally (plesiopotamic) connected oxbows. Functional diversity was investigated using a trait‐based approach as surrogates of ecosystem processes. A total of 28 fish species were identified, including 14 non‐native species. Our results show that main channel and plesiopotamic oxbows exhibited distinct compositional and structural patterns of fish communities, while parapotamic oxbows displayed an intermediate composition and community structure. Taxonomic and functional diversity decreased along the lateral continuum from the main channel to plesiopotamic waterbodies. In contrast, while non‐native species richness was similar between the main channel and floodplains, their densities were higher in floodplain oxbows. These findings highlight the prominent role of hydrological connectivity in sustaining both taxonomic and functional diversity in riverine ecosystems. Fish community variations between habitats may be explained by physical changes resulting from reduced connectivity, primarily characterised by a loss of depth and surface area, which in turn affect a broad spectrum of abiotic and biotic factors. High densities of non‐native species in lentic environments like oxbows can be attributed to specific abiotic conditions (e.g., hypoxia, rapid temperature fluctuations and eutrophication) and the greater tolerance and plasticity of non‐native species compared to native species. Additionally, the absence of predators reduces top‐down control and intensifies competition with native species for resources. Conservation and management strategies should prioritise preserving and restoring connectivity to support native fish communities, limit the dominance of non‐native species, and maintain the ecological integrity of freshwater ecosystems
Villes d'Asie : entre imaginaire et réalité
No full textVues d’Europe, les villes d’Asie semblent à l’écart du monde, repoussées à sa périphérie, parfois réduites à de simples objets de curiosité. Cependant, certaines d’entre elles s’enorgueillissent d’un passé prestigieux. Centres cosmopolites avant l’ère de la mondialisation ou encore hauts lieux culturels, d’aucunes continuent même de bénéficier de ce statut. Les villes d’Asie ont également été lieux de passage ou d’immigration ; diverses populations et voyageurs du monde entier s’y sont toujours déplacés pour d’innombrables raisons. Le brassage des populations et les échanges commerciaux et culturels n’ont toutefois pas toujours été idylliques. Celles-ci ont également fait l’objet de convoitises, d’invasions, de guerres et de colonisation. Échanges et métissages se sont également conjugués avec des expériences douloureuses et déchirantes. Sources de fascination ou de détestation, ces villes asiatiques ont longtemps attiré le regard d’auteurs et d’artistes du monde entier. Ces derniers les ont étudiées sur les plans historique, géographique, sociologique, anthropologique, mais aussi sur le plan de l’expression littéraire et artistique à travers les romans, la poésie, le cinéma, la photographie, l’architecture, etc. Ainsi, loin d’être fermées et excentrées, les villes asiatiques ont souvent été des espaces cosmopolites et ouvertes au monde. L’objectif de cet ouvrage est de prolonger cette idée d’ouverture sur le monde et d’offrir à tout un chacun l’occasion de découvrir des aspects méconnus de ces villes asiatiques, à encourager la démarche qui consiste à confronter l’imaginaire et la réalité des mondes passés et contemporains tout en adoptant un point de vue géocritique
Markovian dynamics of single-rebit open quantum systems with applications to colour perception
No full textThis paper investigates the Markovian dynamics of open two-state quantum systems defined over the real numbers (rebits). Two main objectives are pursued. First, we present a comprehensive classification of Markovian rebit quantum channels, i.e. one-parameter semigroups of completely positive, trace-preserving (CPTP) maps acting on the rebit state space. We show that a full characterisation of their action can be achieved and that describing these channels as solutions of the GKSL equation allows us to explicitly identify the associated Lindblad generators and conditions for complete positivity. Second, we present an original application of this classification to colour perception. Using a recent model in which perceived colours arise from Lüders measurements on the rebit state space, we show how chromatic distortion induced by a non-neutral illuminant can be modelled by a Markovian rebit channel that progressively diminishes colour distinguishability. Other types of channels could be used to study colour vision deficiencies. These phenomena are illustrated by simulations on digital images, highlighting the relevance of rebit Markovian dynamics in modelling colour vision
Global drivers of variation in blood mercury of seabirds revealed by a meta-analysis
No full textInternational audienceMercury (Hg) is a global contaminant that biomagnifies in marine food webs. Seabirds can serve as valuable bioindicators of marine Hg pollution due to their high trophic positions and broad distributions. However, the biological and spatial drivers of variation in seabird Hg levels remain unclear, and few studies have validated whether seabird-derived estimates of the spatial distribution of Hg are consistent with predictions from biogeochemical-ocean models. We conducted a global meta-analysis of total Hg (THg) concentrations in adult seabird blood. Based on our own fieldwork and a literature review, we compiled 478 mean THg values from 108 species representing >11,000 individuals. Blood THg increased in species feeding at higher trophic levels, with larger body mass, and those more likely to consume mesopelagic prey in oceanic waters. Additionally, blood THg might further increase in regions with low chlorophyll-a level, likely due to greater methylmercury uptake in areas with low-productivity. We subsequently developed models to predict global spatial variation in seabird blood THg, either from all species or only epipelagic prey feeders. Only our epipelagic prey feeder-based model showed a weak significant positive correlation with THg in particulate organic matter from biogeochemical- ocean models. However, the low correlation coefficient (r =0.23) indicates potential discrepancies between the two models. We suggest that future studies adopt our integrative approach, combining biological data and large-scale modeling, to improve our understanding of global marine Hg pollution. Together, these findings clarify the biological and environmental drivers of Hg exposure in seabirds and highlight the value of seabirds for global monitoring of marine Hg pollution
Mercury and other trace elements in gull chicks from a highly urbanised environment: effects on chick growth, physiology, and health condition
No full textInternational audienceCoastal urbanisation has increased the exposure of urban-dwelling organisms to contaminants, such as trace elements (TEs) in opportunistic seabirds. This exposure may cause detrimental health effects, especially during sensitive early life-stages, before detoxification mechanisms are fully developed. We monitored yellow-legged gull (Larus michahellis) chicks in the city of Porto, Portugal, and collected down feathers and blood for mercury (Hg) and other TE analyses. We aimed to i) evaluate the effects of maternal exposure to Hg (inferred from down feathers) on early chick development, and ii) examine the impact of blood TE contamination on chick physiology and health condition. Aligned with previous research, blood Hg decreased as chicks aged (up to the 5th week), due to the growth dilution effect and depuration into the growing feathers. Additionally, down feather Hg concentrations showed a limited transfer of Hg from females to the embryo and was unrelated to hatching mass or early growth rate. While low maternal Hg exposure resulted in no detectable effects on early-life development or chick survival, dietary exposure (inferred from blood) to other TEs incurred physiological costs. Blood arsenic (As) and lead (Pb) concentrations were associated with a faster erythrocyte sedimentation rate, suggesting impaired immune response and inflammation. This highlights a dichotomy between transgenerational Hg transfer and post-hatching dietary exposure to Hg and other TEs. Future work should aim to define toxicity thresholds for TEs in seabird chicks, investigating the implications in the health since early life stages, to better integrate the observed physiological responses
Microplastics quantification in organic-rich samples: the relevance of testing substrate-specific calibration curves
No full textInternational audienceUrban agriculture could rely on waste-based substrates, but potential contaminants such as microplastics should be evaluated for safe public use. However, quantifying macroplastics in these substrates is challenging due to their high organic matter content, which is difficult to remove completely, leading to interfering compounds and unreliable results. This study investigated the underexplored effects of organic matter on microplastics quantification employing pyrolysis-GC-MS. Natural organic matter (NOM) removal methods were tested on organic-rich peat-based substrate, reaching up to 46% of reduction with Fenton’s reaction. Then, calibration curves were prepared in two inorganic matrices, silicon dioxide and glass fiber powders, for high density polyethylene (HDPE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC) across nine concentrations, from 0.01 to 10 µg/mg, adding polyflurostyrene (PFS) as internal standard. The selectivity of several polymer pyrolytic markers was compared. Polymer-spiked samples were subjected to Fenton’s oxidation and quantified with both inorganic calibration curves, overestimating polymer contents, up to four times for PET and PVC. The preparation of a third calibration curve, specific for peat, improved results for PS, but not for PP, PET, and PVC. For the first time, the three calibration curves were tested on untreated polymer-spiked (HDPE, PP, PS) waste-based substrates, and resulted in a better estimation closer to the expected polymer concentrations when substrates closely matched the curve’s matrix composition. The comparison of three calibration curves made with different matrices showed that the quantification of plastic polymers in organic-rich samples could be improved using matrix-specific calibration curves even without a complete NOM removal. This represents a novel methodological approach for plastic polymers quantification in complex matrices, minimizing the sample pre-treatment that could cause the loss of nanoparticles during filtration, evidencing that matrix similarity is key for reliable quantification in NOM-rich samples, even without its complete removal
Documents inédits relatifs à la connaissance de la Chine en France de 1685-1740
No full textVirgile PINOT Documents inédits relatifs à la connaissance de la Chine en France de 1685-1740”，1932，Paul Geuthner这本1932年由法国巴黎Paul Geuthner东方出版社出版的关于十八世纪中国知识的图书法文版一共183页，至今未曾翻译成中文。该书汇聚了一些在法国从未发表过的关于十八世纪（1685-1740）中国知识的起源和形成的文件，里面主要包括了弗雷德写给来华耶稣会士的信件。这些珍贵的信件交流对历史学家研究十八世纪中国知识在法国的形成非常重要。该书选出的很多信件来源于天文学家德里斯勒的收藏，他原本想撰写一部介绍古老的东方的天文学的书籍，为了写这本书，他与在中国的耶稣会士不停地书信往来以获取天文观察的信息和第一手资料。在弗雷德去世后，他又花钱买下了弗雷德曾经保存的中国天文方面的资料。该书中一部分的信件是在华耶稣会士福凯写给法国国内的重要人物。书中的第一部分是法国巴黎科学院给柏应理在1684年到达法国时准备的关于中国的问题清单，这足以看到十七世纪末法国对中国的研究和探索已经相当全面了。将这本书译成中文不但能帮助我国普通读者了解早期中法文化交流的历史，还能为研究中法关系领域的专家学者提供研究的历史依据，并对两国今后两国的文化交流会起到重要作用