Drainage network analysis to comprehend structural sediment (dis)connectivity in wine-growing Beaujolais (France)

International audienceDrainage infrastructure is an important element of the agricultural landscape, influencing hydro-sedimentary transfers from plots to rivers. The objective of this article is to demonstrate how the description of the main characteristics of drainage networks allows a better understanding of sediment (dis)connectivity. This study focuses on an 8 km2 catchment in the Beaujolais vineyards (France) that is characterized by a complex drainage network. We applied methods using field surveys, a geographical information system and graph theory to map and analyse how such man-made infrastructures may act as barriers, buffers or shortcuts. The catchment shows dense and complex drainage networks characterized by sediment trapping strategies in the upper slopes, and flow concentration and export in the lower slopes. The results exemplify winegrowers’ strategies to disconnect sediments sources from the river to preserve soil resources

The effect of cosmic rays on the observational properties of the CGM

International audienceThe circumgalactic medium (CGM) contains information on the cumulative effect of galactic outflows over time, generally thought to be caused by feedback from star formation and active galactic nuclei. Observations of such outflows via absorption in CGM gas of quasar sightlines show a significant amount of cold (⁠|${\lesssim}10^4\,{\rm K}$|⁠) gas, which cosmological simulations struggle to reproduce. Here, we use the adaptive mesh refinement hydrodynamical code Ramses to investigate the effect of cosmic rays (CR) on the cold gas content of the CGM using three zoom realizations of a z = 1 star-forming galaxy with supernova mechanical feedback: one with no CR feedback (referred to as no-CR), one with a medium CR diffusion coefficient |$\kappa = 10^{28} \, \rm {cm^{2}\, s^{-1}}$| (CR−κ_med), and one with a high rate of diffusion of |$\kappa = 3\times 10^{29} \, \rm {cm^{2}\,\, s^{-1}}$| (CR−κ_high). We find that, for CR−κ_med, the effects of CRs are largely confined to the galaxy itself as CRs do not extend far into the CGM. However, for CR−κ_high, the CGM temperature is lowered and the amount of outflowing gas is boosted. Our CR simulations fall short of the observed Mg ii covering fraction, a tracer of gas at temperatures |${\lesssim}10^4\,{\rm K}$|⁠, but the CR−κ_high simulation is more in agreement with covering fractions of C iv and O vi, which trace higher temperature gas

Ditopic Covalent Cage for Ion‐Pair Binding: Influence of Anion Complexation on the Cation Exchange Rate

International audienceA new hemicryptophane host with a ditopic molecular cavity combining a cyclotriveratrylene (CTV) unit with a tris‐urea moiety was synthesized. The complexation of halides, tetramethylammonium (TMA + ) cation, and ion pairs was investigated. A positive cooperativity was observed, since halides display a higher binding constant when a TMA + cation is already present inside the cage. When TMA + was complexed alone, a decrease of temperature from 298 K to 230 K was required to switch from a fast to a slow exchange regime on the NMR time scale. Nevertheless, the prior complexation of a halide guest in the lower part of the host resulted in significant decrease of the exchange rate of the subsequent complexation of the TMA + cation. Under these conditions, the 1 H NMR signals characteristic of a slow exchange regime were observed at 298 K. Addition of an excess of salts, increases the ionic strength of the solution, restoring the fast exchange dynamics. This result provides insight on how the exchange rate of a cation guest can be modulated by the complexation of a co‐guest anion

Semiotics of Comics in the Digital Age: The Case of Myths

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Hybridising geographically weighted regression and multilevel models: a new approach to capture contextual effects in geographical analyses

International audienceMultilevel models are one of the main statistical methods used in modelling contextual effects in social sciences. A common limitation of these methods is the use pre-set boundaries – usually administrative units – to define contexts, when these boundaries do not always match up with the “true” causally relevant contexts that may affect the outcomes of interest. In this study applied to the obesity geography in the Paris area (France), we propose a new spatially explicit two-step procedure to tackle this methodological issue. The first step consists in estimating a geographically weighted regression (GWR) model, then using it to reveal and delineate relevant non-stationarity-based data-driven spatial contexts, and finally including them as a random effect into a random slope multilevel model. In applying this hybrid methodology for modelling body mass index (BMI) within a sample of 9,089 French adults, we demonstrate that it outperforms administrative-based multilevel models in terms of decreasing Akaike information criteria (AIC), and is better at accounting for contextual effects through intraclass correlation coefficient (ICC) and increasing slope variance. We suggest that this procedure might be generalized to quantitative geographical analyses involving contextual effects

Euclid: Early Release Observations -- A preview of the Euclid era through a galaxy cluster magnifying lens

International audienceWe present the first analysis of the Euclid Early Release Observations (ERO) program that targets fields around two lensing clusters, Abell 2390 and Abell 2764. We use VIS and NISP imaging to produce photometric catalogs for a total of $\sim 500\,000$ objects. The imaging data reach a $5\,\sigma$ typical depth in the range 25.1-25.4 AB in the NISP bands, and 27.1-27.3 AB in the VIS band. Using the Lyman-break method in combination with photometric redshifts, we identify $30$ Lyman-break galaxy (LBG) candidates at $z>6$ and 139 extremely red sources (ERSs), most likely at lower redshift. The deeper VIS imaging compared to NISP means we can routinely identify high-redshift Lyman breaks of the order of $3$ magnitudes, which reduces contamination by brown dwarf stars and low-redshift galaxies. Spectroscopic follow-up campaigns of such bright sources will help constrain both the bright end of the ultraviolet galaxy luminosity function and the quasar luminosity function at $z>6$, and constrain the physical nature of these objects. Additionally, we have performed a combined strong lensing and weak lensing analysis of A2390, and demonstrate how Euclid will contribute to better constraining the virial mass of galaxy clusters. From these data, we also identify optical and near-infrared counterparts of known $z>0.6$ clusters, which exhibit strong lensing features, establishing the ability of Euclid to characterize high-redshift clusters. Finally, we provide a glimpse of Euclid's ability to map the intracluster light out to larger radii than current facilities, enabling a better understanding of the cluster assembly history and mapping of the dark matter distribution. This initial dataset illustrates the diverse spectrum of legacy science that will be enabled by the Euclid survey

Les représentations de la démocratie à l'épreuve des espaces métropolitains : l'adhésion ambivalente du personnel politique intercommunal à la division scalaire du travail politique

International audienceL’avènement de métropoles dans le paysage administratif français ­­n’a pas échappé aux critiques sur les fondements démocratiques de ces nouvelles institutions. Cet article propose ­­d’analyser les perceptions du personnel politique métropolitain : comment ce personnel envisage les procès récurrents et, plus largement, comment ­­pense-­­t-il la démocratie à une échelle métropolitaine ? ­­L’article croise pour cela des données quantitatives et qualitatives pour montrer ­­l’acceptation ­­d’une division fonctionnelle des échelles de pouvoir : à chaque échelle (municipale et métropolitaine), la nature du travail politique et les partenaires changent. Ces représentations contrastent avec les conclusions ­­d’une abondante littérature scientifique évoquant un emboîtement des échelles

Sheller, l'intime sous le choral : rayonnement d'un homme heureux ?

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L’oppidum du Castellas à Murviel-lès-Montpellier (Hérault). Nouveaux acquis sur l’occupation de la fin de l’âge du Fer (IIIe-Ier s. av. n. è.)

International audienceThis paper specifically highlights on the results of the 2010-2018’s excavation campaigns located on the top of the Castellas at Murviel-lès-Montpellier (34, France), which is best known for the Gallo-Roman period. The investigations focused on the northern part of the enclosure wall, specifically near one of the entrances identified during the ancient excavations. The new insights date the foundation of the “oppidum” in the middle or the second half of the 3rd century BC. For the first time, this field- work has characterised the Protohistoric occupation on the site as well as its evolution. It appears as a clustered settlement of nearly 4 ha, protected behind a powerful fortification. The several remains discovered on the Castellas have many similarities with the main contemporary fortified settlements in the Eastern Languedoc. Reflec- ting excavated areas, the hilltop, after more than two centuries of a continuous activity, is definitively abandoned after the reign of Emperor Augustus. From then on, the city, which then covered 20 ha, spread out mainly on the slopes of the hill.Cet article présente les résultats des campagnes de fouille menées entre 2010 et 2018 sur la partie sommitale du site du Castellas de Murviel-lès-Montpellier, qui est sur- tout connu pour la période gallo-romaine. Les investigations ont porté sur le secteur nord de l’enceinte, en particulier aux abords d’une des entrées repérées anciennement. Les données nouvellement acquises permettent d’établir la date de fondation de l’oppidum vers le milieu ou dans la seconde moitié du IIIe s. av. n. è. Elles permettent éga- lement de caractériser pour la première fois l’occupation protohistorique du site, ainsi que d’en retracer l’évolution. L’image qui ressort est celle d’un habitat aggloméré et bien structuré de près de 4 ha, protégé derrière une puissante fortification. Les différents vestiges découverts trouvent de nombreux points de comparaison avec les princi- paux établissements fortifiés contemporains du Languedoc oriental. Si l’on en juge par les zones fouillées, le sommet de la colline, après plus de deux siècles d’occupation continue, n’est définitivement plus habité à partir du règne d’Auguste, l’agglomération, qui atteint alors 20 ha, se développant dès lors principalement au pied du relief