Urban tree diversity fosters bird insectivory despite a loss in bird diversity with urbanization

Urbanization is one of the main drivers of biotic homogenization in bird communities worldwide. Yet, only a few studies have addressed its functional consequences on the top-down control birds exert on insect herbivores. We hypothesized that their inconsistent results reflect the overlooked heterogeneity of the urban habitat for birds, and in particular the distribution and diversity of urban trees. We monitored tree diversity, bird diversity, avian predation attempts on artificial prey, and the effect of bird exclusion on insect herbivory in 97 trees distributed among 24 urban experimental plots in the city of Montreal, Canada. We characterized urbanization levels through a combination of variables related to tree density, impervious surfaces, anthropic noise, and human population density. Bird diversity decreased with increasing urbanization, whereas the frequency of generalist synurbic species increased. We found no significant relationship between predation and urbanization or between predation and bird diversity. However, tree diversity was positively correlated with predation attempts on artificial prey, irrespective of bird diversity. We revealed a mismatch between the effects of urbanization on bird diversity and on the regulation service and unraveled the functional importance of tree diversity in shaping the avian predation function in urban ecosystems. Our study advocates for the consideration of intra-urban heterogeneity in the investigation of trophic cascades within cities

Clin Chim Acta

Glycation is a non-enzymatic, post-translational modification of proteins which is elevated in several pathologies, notably diabetes. An early-stage glycation product, glycated hemoglobin (HbA1c), is used in the clinical management of diabetes, and advanced glycation end-products (AGEs) are implicated in the etiology of diabetic complications. Fingernail clippings contain a time-integrated repository of several metabolic processes during the preceding 3-5 months, are easily sampled, and various elements and molecules have been shown to remain stable within them for long periods without refrigeration. Building upon a few underexploited studies, we investigated fingernails as a non-invasive matrix to assess glycation using liquid chromatography-mass spectrometry to quantify ungual biomarkers of early- and advanced glycation (respectively furosine, as a fructose-lysine derivative, and two AGEs (N(ε)-carboxymethyllysine (CML) and N(ε)-carboxyethyllysine (CEL)). The method was appropriately validated and provided accurate and precise measurements of two amino acids and the glycation biomarkers. Sample storage at ± 25 °C for 12 months had no effect upon these analytes, and the method was applied to fingernails from 87 people with diabetes. There was a moderate, linear correlation between ungual furosine concentrations and HbA1c at the time of nail sampling (r(s) = 0.339, p = 0.0011). Among subjects for whom previous measurements were available, there was no correlation between ungual glycation and HbA1c measured > 3 months before nail sampling, indicating that ungual furosine reflects early-stage glycation over a similar period to HbA1c. This study provides further evidence, using modern analytical techniques, that fingernails offer the possibility to quantitatively and non-invasively assess glycation

The social and political determinants of support for democratic innovations in France

Many pundits, politicians, journalists or experts argue that deepening participation is the solution to the crisis of representative democracy in France. Democratic innovations are mechanisms aiming at expanding citizens' participation in political decision-making. However, behind this umbrella concept, democratic innovations come in various forms and shapes: citizen-initiated referendums, abrogative referendums, recall, consultative or binding deliberative mini-publics, etc. Some complement representative democracy whereas others contest directly its logic. This chapter will analyze the political and social determinants of support for two democratic innovations that challenge the traditional elective form of political representation: citizen-initiated referendums, and citizens' assemblies replacing elected representatives to take political decisions, relying on descriptive statistics and regression analyses. We build on the fast-growing literature on process preferences such as direct democratic procedures or randomly selected citizens assemblies. This chapter corroborates other findings and confirms that individuals who are the losers of representative democracy, because they are poorly represented politically, descriptively and substantively are also the most likely to support radical reforms that challenge the core logic of the French political system.UNEQUALCITIZE

De l’idée de Nature(s) à l'idée d'humanités environnementales

La notion ou le concept de « Nature » et son histoire critique, nous semble référer préalablement à la sphère des représentations cognitives et sociales, certes singulières, avant de constituer, tout ou partie, une réalité dont les contours seraient circonscrits précisément. Plus encore, nous pourrions établir, après d’autres, qu’il n’existe finalement que des accès épistémiques culturels à la nature lesquels modifient nécessairement cette idée, comme le souligne à sa manière, le concept « d’humanités environnementales ».Le concept de « Nature » est extraordinairement retors, à la fois labile et insaisissable dans la mesure où il nous apparaît à la fois comme un spectre, i.e. comme une ombre évanescente, d’un point de vue ontologique, et dans un spectre interprétatif possible du terme, une sémantique complexe et saturée, comme un « opérateur conceptuel » foncièrement problématique. Nonobstant, le concept de « nature » et ses multiples usages en viennent à désigner ce qui est notre immédiat irrécusable tel qu’il n’y aurait pas lieu de remonter au-delà. Afin de clarifier le sens qu’endossent certaines notions qui peuvent s’y rattacher, comme celles apparemment de « biosphère », d’ « environnement », d’ « écologie », etc., notre propos vise à rendre compte des présupposés et des enjeux de la topographie du terme de « Nature », de la galaxie catégoriale et lexicale de possibles synonymes, lesquels ne renvoient pas donc directement à un objet réel, mais nous apparaissent dans l’hétérogénéité de ses conceptions, de ses usages, de ses références, ontologiques et sémantiques, comme ce qui peut désigner une idée, voire plus précisément, une sorte de métaconcept. Mais lequel ? Et de quel ordre ? Que révèlent donc sa mise en demeure contemporaine, sa possible problématique « obsolescence programmée », selon Philippe Descola? En effet, l’absence de la notion ou du concept ne signifie, ni la prétendue absence d’une représentation peu ou prou équivalente dans d’autres cultures que la nôtre, ni n'invalide le caractère d'efficience des investigations conceptuelles et expérimentales des "champs de réalités" du réalisme et du rationalisme scientifique, à propos de l'idée de Nature(s), comme le souligne Patrick Dupouey dans son examen critique et philosophique des apories et des paradoxes de l'anthropologie descolienne de la nature

Polls in the representative link: the commissioning of polls by the French Presidents Sarkozy and Macron

La fabrication de l'opinion publique sondagière en France et en Allemagn

Int. J. Intercult. Rel.

The paper discusses the importance of considering diversity in public institutions and the need for intercultural training for practitioners. It emphasizes the psychological characteristics essential for dealing with diversity, focusing on multicultural personality traits, host community acculturation orientations, and adult attachment. The study aims to assess these psychological characteristics in future social workers and occupational therapists across three settings (France, n=273, Quebec, n=63, and Switzerland, n=66) before their integration internships. It is expected that certain personality profiles will be associated with favorable acculturation orientations and secure attachment, while others will be linked to less welcoming acculturation orientations and insecure attachment. Participants completed the Multicultural Personality Questionnaire (MPQF), the Host Community Acculturation Scale (HCAS) and the Revised Adult Attachment Scale (R-AAS). Analysis methods include hierarchical cluster analysis on the MPQF to identify intercultural personality profiles and subsequent ANOVAs to explore associations with acculturation orientations and attachment dimensions. Four multicultural personality profiles are identified: considerate (open and attentive), adaptive (handling new situations well), maladaptive (low scores on all traits, uncomfortable in intercultural situations), and reticent (reserved in intercultural encounters). Specific profiles align with distinct acculturation orientations, such as the considerate profile with a rejection of exclusion. Additionally, the adaptive profile displays consistently low anxiety levels. The study highlights that a significant proportion of students (40% to 60%) may lack competence in intercultural contexts. It questions the adequacy of intercultural training in curricula and emphasizes the need for further research on the impact of such training on students’ competence in handling diversity

Rhizochemistry and soil bacterial community are tailored to natural stress gradients.

Plants modulate their rhizochemistry, which affects soil bacterial communities and, ultimately, plant performance. Although our understanding of rhizochemistry is growing, knowledge of its responses to abiotic constraints is limited, especially in realistic ecological contexts. Here, we combined predictive metabolomics with soil metagenomics to investigate how rhizochemistry responded to environmental constraints and how it in turn shaped soil bacterial communities across stress gradients in the Atacama Desert. We found that rhizochemical adjustments predicted the environment (i.e. elevation, R2 between 96% and 74%) of two plant species, identifying rhizochemical markers for plant resilience to harsh edaphic conditions. These metabolites (e.g. glutamic and succinic acid, catechins) were consistent across years and could predict the elevation of two independent plant species, suggesting biochemical convergence. Next, convergent patterns in the dynamics of bacterial communities were also observed across the elevation gradient. Finally, rhizosphere predictors were associated with variation in composition and abundance of bacterial species. Biochemical markers and convergences as well as potential roles of associated predictive bacterial families reflected the requirements for plant life under extreme conditions. This included biological processes such as nitrogen and water starvation (e.g. glutamic and organic acids, Bradyrhizobiaceae), metal pollution (e.g. Caulobacteraceae) and plant development and defence (e.g. flavonoids, lipids, Chitinophagaceae). Overall, findings highlighted convergent patterns belowground, which represent exciting insights in the context of evolutionary biology, and may indicate unique metabolic sets also relevant for crop engineering and soil quality diagnostics. Besides, the results emphasise the need to integrate ecology with omics approaches to explore plant-soil interactions and better predict their responses to climate change

Dynamics of a viscous incompressible flow in presence of a rigid body and of an inviscid incompressible flow in presence of a source and a sink

Dans cette thèse, nous étudions les propriétés des écoulements de fluides qui interagissent avec un corps rigide ou avec une source et un puits. Dans le cas d'un fluide visqueux incompressible qui satisfait les équations de Navier Stokes dans un domaine borné 2D, les solutions faibles de Leray-Hopf sont bien comprises. L'existence et l'unicité sont prouvées. De plus, les solutions sont continues en temps `a valeurs dans L 2 (Omega) et satisfont l’égalité d'énergie classique. Plus récemment, le problème d'un corps rigide en mouvement dans un fluide visqueux incompressible modélisé par les équations de Navier-Stokes couplées aux lois de Newton qui décrivent le mouvement du solide a également été abordé dans le cas où des conditions aux limites sans glissement ont été prescrites. Des résultats analogues concernant les solutions de Leray-Hopf ont également été démontrés dans ce contexte. Dans ce manuscrit, nous étudions le cas de conditions aux limites de Navier-Slip. Dans ce cadre, le résultat d'existence pour le système couplé a été prouvée par G'erard-Varet et Hillairet en 2014. Ici, nous montrons que les solutions sont continues en temps, qu'elles satisfont l’égalité d'énergie et qu’elles sont uniques. De plus, nous montrons un résultat d'existence des solutions faibles dans le cas d'un fluide incompressible visqueux auquel s'ajoute un corps rigide dans le cas où la vitesse du fluide a une partie orthonormale d'énergie infinie.Pour un fluide incompressible non visqueux modélisé par les équations d'Euler dans un domaine borné 2D, le cas où le fluide est autorisé à entrer et à sortir de la frontière a été traité par Judovic qui a introduit certaines conditions limites consistant à prescrire la composante normale de la vitesse et de la vorticité entrante. Dans ce manuscrit, nous considérons un domaine borné qui possède deux trous. L'un d'eux est une source, ce qui signifie que le fluide est autorisé à entrer dans le domaine et l'autre est un puits où le fluide peut sortir. En particulier, nous établissons les équations limites vérifiées par le fluide lorsque la source et le puits se contractent en deux points différents. Le système limite est caractérisé par un point source/puits et un point vortex en chacun des deux points où les trous se sont contractés.In this thesis, we investigate properties of incompressible flows that interact with a rigid body or a source and a sink. In the case of an incompressible viscous fluid that satisfies the Navier Stokes equations in a 2D bounded domain well-posedness of Leray-Hopf weak solutions is well-understood. Existence and uniqueness are proved. Moreover solutions are continuous in time with values in L 2 (Omega) and they satisfy the energy equality. Recently the problem of a rigid body moving in a viscous incompressible fluid modeled by the Navier-Stokes equations coupled with the Newton laws that prescribe the motion of the solid, was also tackled in the case where the no-slip boundary conditions were imposed. And the correspondent well-posedness result for Leray-Hopf type weak solutions was proved. In this manuscript we consider the case of the Navier-slip boundary conditions. In this setting, the existence result for the coupled system was proved by G'erard-Varet and Hillairet in 2014. Here, we prove that solutions are continuous in time, that they satisfy the energy equality and that they are unique. Moreover we show an existence result for weak solutions of a viscous incompressible fluid plus rigid body system in the case where the fluid velocity has an orthoradial part of infinite energy.For an inviscid incompressible fluid modelled by the Euler equations in a 2D bounded domain, the case where the fluid is allowed to enter and to exit from the boundary was tackled by Judovic who introduced some conditions which consist in prescribing the normal component of the velocity and the entering vorticity. In this manuscript we consider a bounded domain with two holes, one of them is a source which means that the fluid is allowed to enter in the domain and the other is a sink from where the fluid can exit. In particular we find the limiting equations satisfied by the fluid when the source and the sink shrink to two different points. The limiting system is characterized by a point source/sink and a point vortex in each of the two points where the holes shrunk

Design of generic modular solutions for PDE solvers for modern architectures

La simulation numérique fait partie intégrante du processus d'analyse. Que l'on veuille concevoir le profil d'un véhicule, ou chercher à prévoir le résultat d'un forage pétrolier, la simulation numérique est devenue un outil complémentaire à la théorie et aux expérimentations. Cet outildoit produire des résultats précis en un minimum de temps. Pour cela, nous avons à disposition des méthodes numériques précises, et des machines de calcul aux performances importantes. Cet outil doit être générique sur les maillages, l'ordre de la solution, les méthodes numériques, et doitmaintenir ses performances sur les machines de calculs modernes avec une hiérarchie complexes d'unité de calculs. Nous présentons dans cette thèse le background mathématiques de deux classes de schémas numériques, les méthodes aux éléments finis continus et discontinus. Puis nous présentons les enjeux de la conception d'une plateforme en prenant en compte l'ensemble de ces contraintes. Ensuite nous nous intéressons au sous-problème de l'assemblage au dessus d'un support d'exécution. L'opération d'assemblage se retrouve en algèbre linéaire dans les méthodes multi-frontales ou dans les applications de simulations assemblant un système linéaire. Puis, nous concluons en dressant un bilan sur la plateforme AeroSol et donnons des pistes d'évolution possibles.Numerical simulation is nowadays an essential part of engineering analysis, be it to design anew plane, or to detect underground oil reservoirs. Numerical simulations have indeed become an important complement to theoretical and experimental investigation, allowing one to reduce the cost of engineering design processes. In order to achieve a high level of precision, one need to increase the resolution of his computational domain. So to keep getting results in reasonable time, one shall nd a way to speed-up computations. To do this, we use high performance computing, HPC, to exploit the complex architecture of modern supercomputers. Under these two constraints, and some other like the genericity of finite elements, or the mesh dimension, we developed a new platform AeroSol. In this thesis, we present the mathematical background, and the two types of schemes that are implemented in the platform, the continuous finite elements method, and the discontinuous one. Then, we present the design choices made in the platform,then, we study a sub-problem, the assembly operation, which can be found in linear algebra multi-frontal methods

Adaptive residual based schemes for solving the penalized Navier Stokes equations with moving bodies : application to ice shedding trajectories

La prédiction de mouvement de solide évoluant dans un fluide présente un réel intérêt pour des applications industrielles telle que l’accrétion de glace sur des surfaces aérodynamiques. Dans ce contexte, en considérant des systèmes de dégivrage, la prévision des trajectoire de glace est nécessaire pour éviter des risques de collision/ingestion de glace sur/dans des zones sensibles de l’avion. Ce type d’application soulève de nombreux challenges d’un point de vue numérique, en particulier concernant la génération/l’adaptation de maillage au cours du mouvement du solide dans le domaine. Pour gérer ces difficultés, dans cette étude, les solides sont définis de manière implicite via une fonction level set. Une méthode de type frontière immergée, appelée Pénalization, est utilisée pour imposer les conditions de bords. Pour améliorer la précision de l’interface, les équations sont résolues sur des maillages non structurés adaptatifs. Cela permet d’obtenir un raffinement proche des bords du solide et ainsi d’améliorer sa définition, permettant un meilleure impositions des conditions de bord. Pour économiser du temps de calcul, et éviter de coûteuses étapes de remaillage/interpolation, la stratégie adoptée pour les simulations instationnaires est d’utiliser une adaptation de maillage à connectivité constante, aussi appelée r-adaptation.The prediction of solid motion evolving in a fluid presents a real interest for engineering application such as ice accretion on aerodynamics bodies.In this context, considering de-icing systems, the ice shedding trajectory is needed to prevent the risk of collision/ingestion of the ice in/with some sensitive part of the aircraft. This application raises many challenges from a numerical point of view, especially concerning mesh generation/adaptation as the solid moves in the computational domain. To handle this issue, in this work the solids are known implicitly on the mesh via a level set function. An immersed boundary method, called penalization, is employed to impose the wall boundary conditions. To improve the resolution of these boundaries, the equations are solved on adaptive unstructured grids. This allows to have are finement close to the solid boundary and thus increases the solid definition,leading to a more accurate imposition of the wall conditions. To save computational time, and avoid costly remeshing/interpolation steps, the strategy chosen for unsteady simulations is to use a constant connectivity mesh adaptation,also known as r-adaptatio