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Des globes virtuels aux déserts de données. Penser l'inégale géonumérisation du Monde par (et avec) la géomatique.
No full textInternational audienceDigital globes are emerging as one of the latest avatars in the cartography of global changes. Taking them as its object of study, SPHEROGRAPHIA is a research project with a twofold objective: firstly, to better understand the making of virtual globes through analysis of their promoters' intentions and the different ways in which they are constituted, by tracing the genealogy of their sources to reveal the disparities in the data underlying these visualizations; secondly, the project questions the performativity of globes on the imaginations and political commitments of those who feed them or use them. In this paper, we propose to intervene in two of the project's workstreams: on the one hand, a statistical exploration of more than 400 globes, which will enable us to describe the data mobilized, their context of use and semiotic choices; on the other hand, a focus on a case study centered on virtual globes devoted to biodiversity, in order to go beyond the apparent data deluge and reveal the data gap masked by these geovisualizations. To conclude, this contribution proposes to reflect on how geomatics can contribute to current discussions on the unequal geonumerization of the world. From both a theoretical and a methodological point of view, we will argue for the importance of GISciences taking the turn of critical data studies
Impact of chain extension on the melt strength properties of 3D printed high-performance polyphtalamides using fused granulate fabrication (FGF) process
No full textInternational audienceThe Fused Filament Fabrication (FFF) 3D printing is the most common and widespread additivemanufacturing (AM) technique, but it requires the manufacturing of filaments. Fused Granular Fabrication(FGF), in which pellets are directly 3D printed, has become a promising technique for AM technology [1].The prsent study is particularly focused on injection molding grade high performance polyphtalamides(PPAs) used in the automotive industry because of their excellent mechanical and thermal resistanceproperties. Two strategies were deployed to enhance the melt strength of PPAs in order to be suitable forthe FGF process. The first was a partially reactive way where PA6T/6I copolymers continue to postpolymerizewhen they melt and the holding time in the extruder of the 3D printer was in-depth controled[2]. The collected PPA samples were further examined and demonstrated an increase in the molar massand in the melt viscosity with time as measured by GPC and rheological tests, respectively. The secondroute was a reactive way where the reaction of the PPAs in the presence of 1, 3-Phenylene-Bis-2-Oxazoline(PBO) and 1,1-Carbonyl-Bis-Caprolactam (CBC) as chain extender were performed using a twin-screwextruder [3]. The effect of concentration of PBO reacting with the carboxylic end groups and the CBC withthe amine end groups on the melt processability behavior were investigated. A design of experiments wasthen employed to optimize the most important printing parameters based on Charpy impact, three-pointbending and short-beam shear tests. The effectiveness of developped approaches to easily improve themelt strength of high performances semiaromatic copolyamides (PPAs) for direct pellet printing is thusdemonstrated, allowing the possibility of transposing these finding to highly-filled glass fiber PPAscomposites dedicated to aerospace industry.AcknowledgmentsThis work has been funded through financial support from the French Carnot Institute “Ingénierie@Lyon”assigned to the project RETPAM.References[1] Yousfi, M., Belhadj, A., Lamnawar, K., & Maazouz, A. 3D printing of PLA and PMMA multilayered model polymers:An innovative approach for a better-controlled pellet multi-extrusion process. In ESAFORM 2021, 14 – 16 April, Liège,Belgium.[2] Yousfi, M.; Dkier, M.; Colella, M.; Lamnawar, K.; Maazouz, A. Composites based on polyphtalamides matrices andcontinuous glass fibers: structure-processing and properties relationships. International Journal of Material Forming2021, 14, 175-190.[3] Buccella, M.; Dorigato, A.; Caldara, M.; Pasqualini, E.; Fambri, L. (2013). Thermo-mechanical behaviour ofpolyamide 6 chain extended with 1, 1′-carbonyl-bis-caprolactam and 1, 3-phenylene-bis-2-oxazoline. Journal ofPolymer Research 2013, 20, 1-9
Development of Tungsten-based contrast agents for Spectral Photon counting computed Tomography (SPCCT) scanner
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« De l’épigramme grecque au poème fin-de-siècle : Renée Vivien, traductrice de Nossis (1904) »
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From the material to the immaterial: digital comparative anatomy for archaeological ungulates
No full textInternational audienceContext The identification of faunal remains (bones and teeth) found in archaeological contexts is based on a visual comparison of the shape and size of the bones with their modern counterparts. This comparative anatomy work draws on several morphological criteria identified for given species in present-day environments. However, the application of anatomical criteria by archaeozoologists presents two significant challenges. Firstly, while most of the criteria can be used to identify species, some are present in other species within the same genus or family, which limits identification and results in a significant loss of information. Secondly, there are discrepancies between the anatomical description of the criterion and its observation on the archaeological find. These discrepancies may be due to imprecise vocabulary, a lack of anatomical knowledge or subjectivity in the anatomical representation. This can lead to errors in anatomical identification.Main argumentIn light of these considerations, we sought to ascertain how these anatomical shapes could be described and observed using 3D imaging and supervised learning algorithms. The objective is to create a reliable and reproducible digital reference database based on expert knowledge. While the combination of topological data analysis and kernel matrices has yielded promising results in differentiating between wild and domestic species with similar morphological characteristics (Vuillien et al., 2024), the lack of a defined benchmark hinders the interpretation of the results from a morphological perspective. Furthermore, the construction of a digital database necessitates the utilisation of numerically discernible anatomical criteria. This prompted us to ask the following questions: We would like to ascertain whether the anatomical criteria observed on the bones are identical to those observed on the 3D scanned part (Figure 1). Are there specific criteria that apply only to the 3D object? If so, can these newly identified criteria be considered reliable identification keys?ApplicationsTo address these questions, we collaborated with archaeozoologists and mathematicians on a data set comprising 150 bones from five ungulate species with similar morphological characteristics: ibex, goat, sheep, roe deer and gazelle. While some of these species, such as sheep and goats, have a substantial literature supporting their identification, others, such as roe deer and gazelle, lack sufficient evidence. This work has enabled us to update the available anatomical criteria and to identify and test numerical criteria that are not visible on physical bones. This work forms the basis of future machine learning analyses that will enable us to consolidate the identifications of animals found in archaeological contexts with the help of the expert and to propose new identification criteria that are more mathematically robust
Transition(s) énergétique(s): analyser des trajectoires politiques et territoriales par la géographie historique
No full textFreedom counts: Cross-country empirical evidence
No full textInternational audienceWe investigate whether people attach intrinsic value to freedom and which theoretical rules they implicitly employ to evaluate opportunity sets. To do this, we run a new survey-based study with 4,902 participants across 10 different countries. Participants face various comparisons of opportunity sets in a policy-relevant context in a “spectator” position. Our main result is that an overwhelming majority of spectators reveal that they attach intrinsic value to freedom. We also find that a large majority of participants use size-based rules to rank sets in terms of freedom, while there is considerable heterogeneity in the theoretical rules they implicitly employ to rank sets in terms of welfare. These results are strikingly robust across countries
Training the embodied self in its impermanence: meditators evidence neurophysiological markers of death acceptance
No full textInternational audienceAbstract Background Human predictive capacity underlies its adaptive strength but also the potential for existential terror. Grounded in the predictive processing framework of brain function, we recently showed using a magnetoencephalogram visual mismatch-response (vMMR) paradigm that prediction-based self-specific neural mechanisms shield the self from existential threat—at the level of perception—by attributing death to the ‘other’ (nonself). Here we test the preregistered hypothesis that insight meditation grounded on mindful awareness is associated with a reduction in the brain’s defensiveness toward mortality. In addition, we examine whether these neurophysiological markers of death-denial are associated with the phenomenology of meditative self-dissolution (embodied training in impermanence). Methods Thirty-eight meditators pooled from a previous project investigating self-dissolution neurophenomenology underwent the vMMR task, as well as self-report measures of mental health, and afterlife beliefs. Results were associated with the previously-reported phenomenological dimensions of self-dissolution. Results Meditators’ brains responded to the coupling of death and self-stimuli in a manner indicating acceptance rather than denial, corresponding to increased self-reported well-being. Additionally, degree of death acceptance predicted positively valenced meditation-induced self-dissolution experiences, thus shedding light on possible mechanisms underlying wholesome vs. pathological disruptions to self-consciousness. Conclusions The findings provide empirical support for the hypothesis that the neural mechanisms underlying the human tendency to avoid death are not hard-wired but are amenable to mental training, one which is linked with meditating on the experience of the embodied self’s impermanence. The results also highlight the importance of assessing and addressing mortality concerns when implementing psychopharmacological or contemplative interventions with the potential of inducing radical disruptions to self-consciousness
Vector Competence of Temperate and Tropical Mosquito Species for Babanki virus
No full textBabanki virus (BBKV), an alphavirus belonging to the Western Equine encephalitis complex, was isolated from Mansonia africana mosquitoes in 1969 but is not characterized yet. Transmitted to humans and animals through the bite of an infectious female arthropod, it is associated with febrile illness, rash, and arthritis similarly to Sindbis virus to which it is related. No specific treatment or vaccine is available. To investigate any risk of propagation, our study investigated the vector competence of several mosquito species towards BBKV. For this purpose, laboratory mosquito colonies from metropolitan France: Culex pipiens (Paris), Aedes albopictus (Nice) as well as tropical area: Aedes albopictus (Saint-Benoît, La Réunion) and Culex quinquefasciatus (Slab strain), Aedes aegypti (PAEA) were exposed to an artificial blood meal infected with BBKV molecular clone. Midguts, legs, salivary glands and saliva were collected from individual mosquitoes of different strains or species at various time points to assess the infection status, viral replication, and infectiousness. At 7 days post viral exposure, infection rates exceeded 70% in Aedes and 40% in Culex species. They remain above 50% except for Culex quinquefasciatus which decreases to 35% at 14 days post viral exposure. Using genome and protein detection, the dissemination rates are above 50% except for Aedes albopictus (Nice) at 7 days post viral exposure. Infection assays using VeroE6 cells indicated that BBKV replicative viral particles were found in the saliva of the different populations tested. Our data demonstrate that different mosquitoes’ species from both temperate and tropical areas are competent to transmit BBKV suggesting an emergence risk that could trigger an outbreak in humans. Author Summary Babanki virus (BBKV) is a non-characterized arbovirus identified in 1969 in Cameroon. BBKV is closely related to Sindbis virus which causes symptoms like febrile illness, rash, and arthritis in humans and animals. Both are alphaviruses within the Western Equine Encephalitis complex. BBKV is identified only in the African continent so far. Despite its potential to cause disease, no effective treatments are available. This study investigates the vector competence of various mosquito species from temperate and tropical regions, to transmit BBKV. After mosquitoes were fed an infectious blood meal, various organs were collected at different time points to assess the infection status, viral replication, and infectiousness. The results showed that BBKV infection occurred in all tested mosquito species and persisted over time, with viral particles detected in mosquito or that can potentially be transmitted to vertebrate hosts via mosquito saliva. These findings highlight the broad vector competence of mosquitoes from diverse climatic regions for BBKV, indicating its potential risk for emergence and outbreaks in different regions of the world. The study emphasizes the need for enhanced surveillance and preventive measures to mitigate the potential threat posed by this emerging virus