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City Makers and the Politics of Urban Diversity Governance. Comparative Approaches from Europe and Asia
No full textInternational audienceThis open access book examines the rising challenges of managing diversity in European and Asian cities. It spotlights the roles of varied city makers - from urban leaders to migrant communities and civil society activists - in negotiating and transforming their city’s diversity governance. The book brings together the contributions of urban studies and migration studies scholars, which offer rich empirical analyses on various European and Asian cities, such as Paris, Singapore, Barcelona, and Guangzhou. Adopting a comparative lens, the book presents a decentered understanding of 'super-diverse' cities, examining shifts in urban policy-making within different geographical contexts, with distinct patterns of migration and diversification. By advancing urban comparison as a research tool, it contributes to the contemporary discussions on the local turn of migration and diversity policies
Platinum and Rare Earth Elements distribution in costal sediments from French western Mediterranean Sea
No full textInternational audienceThis study presents the first assessment of Technological Critical Elements (TCE), specifically platinum (Pt) and rare earth elements (REE), in coastal sediments along the French western Mediterranean Sea. These trace elements, increasingly used in advanced technologies, raise particular concerns due to their potential environmental impact. Surface sediment samples were collected from 21 stations along the French Mediterranean coast (from Spain border to Italy including Corsica Island) to evaluate TCE concentrations and identify potential sources. Most of the REE concentrations fell within expected natural levels and were mainly influenced by the geological characteristics of local watersheds, indicating a dominant geogenic origin. When normalized to European Shale, REE distribution patterns exhibited convex shapes, typical of coastal environments. In contrast, localized Pt enrichment were detected at specific sites, particularly in port areas, which could be linked to anthropogenic emissions from vehicular catalytic converters. These results highlight platinum as a relevant emerging contaminant in urban coastal environments. However, unexpected REE and Pt concentrations at the mouth of the Hérault river call for further investigation. This study highlights the importance of integrating geological background and anthropogenic pressures in coastal sediment quality assessments and supports the inclusion of TCE in long -term environmental monitoring programs in the Mediterranean Sea
Rétrospective réflexive sur l’organisation du travail en interdisciplinarité : un projet relatif au nexus moustique-plastique-eau
No full textInternational audienceOur research project investigates the impact of microplastics on Culex mosquitoes, which are vectors of pathogens. We initially focused on ecology, chemistry, and physics, but then broadened our scope to include the social sciences and humanities. This shift aimed to explore how researchers and stakeholders with various levels of involvement in this project conceived the mosquito-plastic-water nexus. Using semi-structured interviews combined with drawing as a research tool, the study revealed fragmented perspectives of the project, influenced by multiple factors. Some participants felt legitimate only within their specific area of expertise, hesitating to depict aspects beyond their direct involvement. Additionally, limited communication at the project’s outset contributed to a partial view of the latter and a limited understanding of its different parts, steps, and methods. These findings highlight the crucial role of internal communication in fostering a shared understanding among the research team. They also underscore the value of interdisciplinary dialogue, enabling better integration between natural and social sciences to address complex environmental challenges. Finally, they open up the way for interdisciplinary approaches to move towards transdisciplinary approaches.Notre projet de recherche porte sur l’impact des microplastiques sur les moustiques du genre Culex, vecteurs de pathogènes. Nous l’avons d’abord centré sur l’écologie, la chimie et la physique, puis élargi aux sciences humaines et sociales pour mettre en question les représentations que les scientifiques et autres acteurs y étant impliqués avaient du nexus moustique-plastique-eau. Des entretiens semi-directifs, intégrant le dessin comme médium, ont révélé parmi l’équipe des visions fragmentées du projet, influencées notamment par un déficit de communication à son lancement, donnant lieu chez ses membres à un sentiment de légitimité limité à leurs propres domaines d’implication. Cette expérience met ainsi en évidence l’importance d’une communication interne renforcée, tout en ouvrant des réflexions sur l’ouverture des approches interdisciplinaires vers la transdisciplinarité
Calibrated Engagement: Chronicles of Local Politics in the Heartland of Myanmar
No full textInternational audienceFor decades, the heartland of Myanmar has been configured as a pacified space under military surveillance. A closer look reveals how politics is enacted at distance with the state. Calibrated Engagement weaves together ethnography and history to chronicle the transformation of rural politics in Anya, the dry lands of central Myanmar. The book presents situations as varied as local elections, inheritance transmissions, land conflicts and ceremonies, to show that politics is about how people calibrate the way they engage with each other
Forms and fluxes of carbon: Surface to deep
No full textInternational audienceCarbon is an essential element for the coevolution of Earth and life, and its largest fraction is stored in the deep Earth. The availability of carbon at the Earth's surface or shallow subsurface over the past 3.8 billion years has been modulated by this reservoir of deep carbon, which has played a fundamental role in the emergence and diversification of life. In turn, major geobiological changes at the Earth's surface have profoundly affected the chemical fingerprints and morphological forms of carbon entering the deep Earth through subduction. This chapter presents an overview of the geology of deep carbon, from its origins and forms throughout the Earth's history, to its movements and fluxes between shallow and deep reservoirs.</div
Tester l'équivalence des "prédateurs" humains et des réseaux neuronaux profonds dans la détection des papillons nocturnes cryptiques
No full textInternational audienceResearchers have shown growing interest in using deep neural networks (DNNs) to efficiently test the effects of perceptual processes on the evolution of color patterns and morphologies. Whether this is a valid approach remains unclear, as it is unknown whether the relative detectability of ecologically relevant stimuli to DNNs actually matches that of biological neural networks. To test this, we compare image classification performance by humans and six DNNs (AlexNet, VGG-16, VGG-19, ResNet-18, SqueezeNet, and GoogLeNet) trained to detect artificial moths on tree trunks. Moths varied in their degree of crypsis, conferred by different sizes and spatial configurations of transparent wing elements. Like humans, four of six DNN architectures found moths with larger transparent elements harder to detect. However, humans and only one DNN architecture (GoogLeNet) found moths with transparent elements touching one side of the moth's outline harder to detect than moths with untouched outlines. When moths took up a smaller proportion of the image (i.e., were viewed from further away), the camouflaging effect of transparent elements touching the moth's outline was reduced for DNNs but enhanced for humans. Viewing distance can thus interact with camouflage type in opposing directions in humans and DNNs, which warrants a deeper investigation of viewing distance/size interactions with a broader range of stimuli. Overall, our results suggest that humans and DNN responses had some similarities, but not enough to justify widespread use of DNNs for studies of camouflage.Les chercheurs s'intéressent de plus en plus à l'utilisation des réseaux neuronaux profonds (RNP) pour tester les effets des processus perceptifs sur l'évolution des motifs et des morphologies des couleurs. La validité de cette approche reste incertaine, car on ne sait pas si la détectabilité relative des stimuli écologiquement pertinents pour les réseaux neuronaux profonds correspond réellement à celle des réseaux neuronaux biologiques. Pour le vérifier, nous avons comparé les performances de classification d'images des humains et de six réseaux neuronaux numériques (AlexNet, VGG-16, VGG-19, ResNet-18, SqueezeNet et GoogLeNet) entraînés à détecter des papillons de nuit artificiels sur des troncs d'arbres. Les papillons artificiels variaient dans leur degré de crypsis, conféré par différentes tailles et configurations spatiales des éléments transparents des ailes. À l'instar des humains, quatre des six architectures DNN ont trouvé que les papillons artificiels dotés d'éléments transparents plus grands étaient plus difficiles à détecter. Cependant, les humains et une seule architecture DNN (GoogLeNet) ont trouvé que les papillons dont les éléments transparents touchaient un côté du contour du papillon étaient plus difficiles à détecter que les papillons dont le contour n'était pas touché. Lorsque les papillons occupent une plus petite proportion de l'image (c'est-à-dire lorsqu'ils sont vus de plus loin), l'effet de camouflage des éléments transparents touchant le contour du papillon est réduit pour les DNN, mais renforcé pour les humains. La distance d'observation peut donc interagir avec le type de camouflage dans des directions opposées chez les humains et les DNN, ce qui justifie une étude plus approfondie des interactions entre la distance d'observation et la taille avec une gamme plus large de stimuli. Dans l'ensemble, nos résultats suggèrent que les réponses des humains et des DNN présentent certaines similitudes, mais invite à l'utilisation prudente des DNN pour les études sur le camouflage
Scaling‐up RADseq methods for large datasets of non‐invasive samples: Lessons for library construction and data preprocessing
No full textInternational audienceGenetic non-invasive sampling (gNIS) is a critical tool for population genetics studies, supporting conservation efforts while imposing minimal impacts on wildlife. However, gNIS often presents variable levels of DNA degradation and non-endogenous contamination, which can incur considerable processing costs. Furthermore, the use of restriction-site-associated DNA sequencing methods (RADseq) for assessing tho
Changes in pollen production, pollen heteromorphism and ovule production with increased selfing in Viola arvensis
No full textInternational audienceBackground and Aims Pollen:ovule ratios are often lower in species and populations with higher selfing rates. This may be due either to higher pollination efficiency through selfing, or to lower male competition when less allo-pollen is available. Changes in pollination can also impact pollen traits, such as the number of apertures. Viola arvensis has experienced a rapid recent increase in selfing rates, and a rapid floral trait evolution towards the selfing syndrome. This study tests the hypothesis that V. arvensis is also undergoing a rapid evolution in its pollen:ovule ratio and pollen heteromorphism. Methods Using the resurrection ecology methodology, we compared four ancestral populations (from ca. 30 years ago) to their descendants (from 2021). We counted ovules and pollen and measured the different pollen aperture morphs in 50 individuals per population. We also developed a model to better understand the links between the number of apertures and the mating system. Key Results We found no temporal change in pollen or ovule production. However, populations with the lowest pollen:ovule ratios were also those with the highest ancestral selfing rates, suggesting that the pollen:ovule ratio could have evolved on a similar timescale to population differentiation. Our model predicts a positive correlation between number of apertures and selfing rates, if pollination parameters remain constant. However, this positive correlation was not found in our results, neither across populations nor through time. Conclusions Unlike floral morphology, pollen and ovule production did not evolve rapidly with increased selfing rates, suggesting a delayed change of the pollen:ovule ratio compared to other traits of the selfing syndrome. The absence of correlation between pollen heteromorphism and selfing rate can be explained by multiple (non-mutually exclusive) factors: a decrease in allo-pollen deposition correlated with the evolution of the selfing syndrome, pollinator declines or the absence of selection in this trait
Comparative genomics of Rickettsiella bacteria reveal variable metabolic pathways potentially involved in symbiotic interactions with arthropods
No full textInternational audienceMembers of the Rickettsiella genus (order: Legionellales ) are emerging as widespread bacteria associated with insects, arachnids, and crustaceans. While some Rickettsiella strains are highly virulent pathogens, others are maternally inherited endosymbionts that manipulate arthropod phenotypes, including the induction of defensive symbiosis and cytoplasmic incompatibility. However, the genomic diversity of Rickettsiella remains largely unexplored, and their genetic potential to induce complex phenotypes in arthropods is only partially understood. In this study, we sequenced five new Rickettsiella genomes isolated from three tick species. Through comparative genomics, we observed that Rickettsiella members share similar metabolic capabilities, and collectively lack virulence genes from pathogenic Legionellales. Additional analysis of Rickettsiella genomes revealed significant variability in metabolic properties related to endosymbiosis. Specifically, their capacity to biosynthesize certain B vitamins and heme varies, suggesting a functional role of some Rickettsiella strains in the nutrition of their arthropod hosts. Some Rickettsiella genomes harbour homologs of Wolbachia cif genes, the cause of Wolbachia -induced cytoplasmic incompatibility, suggesting that Rickettsiella may use a similar molecular mechanism to manipulate the reproduction of their arthropod hosts. Phylogenomics further revealed that tick-borne Rickettsiella exhibit distinct evolutionary origins within the genus, indicating that Rickettsiella have undergone repeated horizontal transfers between ticks and other arthropods
Eukaryote‐wide distribution of a family of longin domain‐containing GAP complexes for small GTPases
No full textInternational audienceArf and Rab family small GTPases and their regulators, GTPase‐activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs), play a central role in membrane trafficking. In this study, we focused on a recently reported GAP for Arf (and potentially Rab) proteins, the CSW complex, a part of a small family of longin domain‐containing proteins that form complexes with GAP activity. This family also includes folliculin and GATOR1, which are GAPs for the Rag/Gtr GTPases. All three complexes are associated with lysosomes and play a role in nutrient signaling, the latter two being directly involved in the mTOR pathway. The role of CSW is not clear, but in addition to having GAP activity on Arf proteins in vitro, its mutation causes severe neurodegenerative diseases. Here we update the reported pan‐eukaryotic presence of folliculin and GATOR1, and demonstrate that CSW is also found throughout eukaryotes, though with sporadic distribution. We identify highly conserved motifs in all CSW subunits, some shared with the catalytic subunits of folliculin and GATOR1, that provide new potential avenues for experimental exploration. Remarkably, one such conserved sequence, the “GP” motif, is also found in structurally related longin proteins present in the archaeal ancestor of eukaryotes