HAL Université de Toulouse, et Toulouse INP
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Silicon-Silica Core-Shell Particles Synthesis for Directional Light Scattering
No full textInternational audienc
Modèle global/local pour l'étude de l'amorçage d'endommagement dans les composites stratifiés épais des lanceurs spatiaux.
No full textInternational audienceModèle global/local pour l'étude de l'amorçage d'endommagement dans les composites stratifiés épais des lanceurs spatiaux
Méthode de mesure CIN-EF / TIR couplée et incertitudes associées dans la construction d'un dialogue essai/calcul robuste
No full textInternational audienceLa mesure de champ multi-physique apparaît comme une étape essentielle pour tirer pleinement parti denos essais sur matériaux. Peu intrusive, cette méthode de mesure ouvre de nouvelles perspectives grâceà la richesse des données qu’elle fournit. Cependant, sa mise en œuvre n’est pas simple et nécessite uncalibrage spatial du capteur. Dans cette étude, nous présentons une méthode de mesure multi-physiquequi permet l’utilisation couplée de capteurs cinématiques et thermiques. Nous exposerons également lespremiers résultats obtenus lors d’un essai de traction réalisé sur un acier inoxydable.La mesure de champ multi-physique apparaît comme une étape essentielle pour tirer pleinement parti denos essais sur matériaux. Peu intrusive, cette méthode de mesure ouvre de nouvelles perspectives grâceà la richesse des données qu’elle fournit. Cependant, sa mise en œuvre n’est pas simple et nécessite uncalibrage spatial du capteur. Dans cette étude, nous présentons une méthode de mesure multi-physiquequi permet l’utilisation couplée de capteurs cinématiques et thermiques. Nous exposerons également lespremiers résultats obtenus lors d’un essai de traction réalisé sur un acier inoxydable
Effect of SBPBF₄ addition in acetonitrile- and linear carbonate-based electrolytes: Improving voltage stability and reducing gas evolution in supercapacitors
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Eco‐evolutionary responses of a cold‐water fish (Salmo trutta) to the combined effects of an emerging pathogen and temperature
No full textInternational audienceHow wildlife populations respond to the different components of global change and their interactions is still poorly understood. For instance, emerging pathogens can directly impact the genetic and phenotypic attributes of their hosts through directional selection or plasticity, whereas climatic stress can either mitigate or exacerbate the infection outcomes. Studying the adaptive response of wild populations to both pathogens and environmental stressors is thus critical for predicting their short-and long-term persistence. We investigated the combined impact of water temperature and infection byTetracapsuloides bryosalmonae, a myxozoan pathogen causing the salmonid proliferative kidney disease (PKD), on wild brown trout Salmo trutta populations. We compared the density, the genetic and phenotypic characteristics of trout populations sampled along gradients of infection prevalence and water temperature, before and after the period of disease outbreaks (summer).3. Population density decreased after the disease outbreak with increasing infection prevalence, regardless of the temperature, except in populations that were already heavily infected the previous year. High infection prevalence reduced genetic diversity at an immune-related gene, regardless of the temperature, but not at neutral loci, in line with pathogen-mediated directional selection. We also showed that both temperature and infection negatively affected trout body condition and had an interactive effect on carotenoid-based coloration, likely reflecting short-term plastic responses of phenotypic traits to both stressors.4. This highlights that different global change stressors (warming and pathogens) can have both negative and interactive effects on fish mortality, genetic diversity and fitness-related traits, and hence on the rapid evolution of wild populations.</div
Increasing tree size across Amazonia
No full textInternational audienceClimate change and increasing availability of resources such as carbon dioxide are modifying forest functioning worldwide, but the effects of these changes on forest structure are unclear. As additional resources become available, for example, through CO2 fertilization or nitrogen deposition, large trees, with greater access to light, may be expected to gain further advantages. Conversely, smaller light-suppressed trees might benefit more if their light compensation point changes, while bigger trees may be the most negatively impacted by increasing heat and drought. We assessed recent changes in the structure of Earth’s largest tropical forest by analysing 30 years of Amazonian tree records across 188 mature forest plots. We find that, at a stand level, trees have become larger over time, with mean tree basal area increasing by 3.3% per decade (95% CI 2.4; 4.1). Larger trees have increased in both number and size, yet we observed similar rates of relative size gain in large and small trees. This evidence is consistent with a resource-driven boost for larger trees but also a reduction in suppression among smaller trees. These results, especially the persistence and consistency of tree size increases across Amazonian forest plots, communities and regions, indicate that any negative impacts of climate change on forests and large trees here have so far been mitigated by the positive effects of increased resources
Removal Processes of the Stratospheric SO2 Volcanic Plume From the 2015 Calbuco Eruption
No full textInternational audienceWe analyze the volcanic plume from the April 2015 Calbuco eruption over a 35-day period using simulations from Meso-NH, a non-hydrostatic mesoscale atmospheric model. A dedicated parameterization of the deep injection of the plume into the stratosphere ensures a realistic representation when compared to Infrared Atmospheric Sounding Interferometer satellite observations. During the first 12 hr of the eruption, on 22 April 2015, SO 2 mixing ratio reached 29 ppmv between 15 and 18 km for the first eruption pulse, and 38 ppmv between 12 and 16 km for the second. Most SO 2 was injected directly into the stratosphere, with a stratospheric load reaching 308 ktS (kilotons of atomic sulfur, i.e. 616 kilotons of SO 2 ) after the eruption. After 1 month, both stratospheric and tropospheric SO 2 loads returned to near-background levels. During analysis, the chemical conversion of SO 2 into H 2 SO 4 removed a part of SO 2 from the stratosphere. During the long-range advection, the co-location between the subtropical jet stream and the Calbuco plume led to three significant stratospheric intrusions on 24, 26 and 28 April 2015. These events transferred stratospheric SO 2 into the troposphere, SO 2 mixing ratios in the upper troposphere reaching 15 ppmv, 26 and 15 ppbv, respectively. SO 2 is gradually oxidized into H 2 SO 4 , with up to 5 ktS of gaseous H 2 SO 4 in the stratosphere on 30 April, but dynamical processes dominate the SO 2 atmospheric budget over chemical transformations. This study demonstrates that stratospheric intrusions can play a critical role in the removal of volcanic material from the stratosphere following a major eruption. Plain Language Summary : The Calbuco volcano had a major eruption in April 2015. This eruption released a toxic gas plume that reached the altitude 20 km in the stratosphere. The plume was transported eastward over the Atlantic and Indian Oceans. The purpose of this article is to detail the transport and chemical evolution of this plume using a dedicated atmospheric model. During its eastward transport through the stratosphere, stratosphere to troposphere exchanges caused part of the volcanic gazes to descend into the troposphere, while the remaining stratospheric part was removed through chemical reactions
Deciphering Letermovir’s Mode of Action and Resistance Mutation Effects
No full textInternational audienceHuman cytomegalovirus is an opportunistic pathogen responsible for severe infections in immunocompromised patients, the leading cause of congenital infections worldwide, and potentially implicated in carcinogenesis. The HCMV terminase complex (pUL56-pUL89-pUL51) has emerged as a key target for antiviral drug development. Letermovir, an antiviral agent targeting this complex, inhibits viral DNA packaging, but resistance-associated mutations have already been identified within subunits. Moreover, the precise mechanism of action of letermovir remains incompletely understood. We investigated interactions among terminase subunits in presence or absence of letermovir. Wild-type and mutant forms of these proteins (including resistance mutations V236M, L241P, L257I, C325Y, R369M in pUL56 and A95V in pUL51) were cloned into NanoBiT® PPI and pCI-neo vectors. Letermovir was added after transfection in HEK293T cells, and protein-protein interactions were assessed. Our results show letermovir does not disrupt interactions between wild-type terminase subunits. Resistance-associated mutations modulate the strength of these interactions, with certain mutations (such as pUL56 V236M and L257I) significantly enhancing or reducing binding. Notably, double mutants exhibited synergistic effects. Structural analyses using the AlphaFold3 platform revealed differences between the mutation site of pUL56 and its HSV-1 counterpart pUL28. A hypothetical 3D analysis based on the cryo-EM structure of the HSV-1 terminase complex showed that resistance mutations were oriented outside the complex. These findings suggest letermovir does not act by directly inhibiting interactions among HCMV terminase subunits. Analysis of resistance-associated mutations provides insight into the molecular basis of HCMV resistance to letermovir and may inform development of novel antiviral strategies targeting the terminase complex
Préparation-conservation et conservation-restauration : des approches similaires au service du patrimoine
No full textAt a time when biodiversity is under threat and humanity faces major challenges, the Muséum de Toulouse offers a contemporary perspective through restoration campaigns of its Naturalia collections and their enrichment with newly created heritage-oriented taxidermy specimens. The museum is regularly confronted with ethical issues when working on protected species and heritage objects. The taxidermy mounts have been conceived to ensure long-term preservation and restorability — a process we refer to as preparation–conservation. This practice raises questions about the roles and boundaries between the professions of taxidermist and conservator-restorer of naturalized specimens. This presentation will discuss both taxidermy creation and restoration campaigns.À l’heure où la biodiversité est en péril et où d’importants défis attendent l’humanité, le Muséum de Toulouse apporte un témoignage contemporain à travers des campagnes de restauration des collections Naturalia et leur enrichissement avec de nouvelles naturalisations patrimonialisées. Il est régulièrement confronté à la déontologie en travaillant sur des espèces protégées et des objets patrimoniaux. Les naturalisations ont été pensées pour être durablement conservées et restaurables : « préparation-conservation ». Cette pratique interroge sur le métier de taxidermiste comme sur celui de conservateur-restaurateur de spécimens naturalisés. Cette présentation évoquera à la fois des campagnes de naturalisation et de restauration
A global map for introgressed structural variation and selection in humans
No full textGenetic introgression from Neanderthals and Denisovan has shaped modern human genomes; however, introgressed structural variants (SVs ≥50 base pairs) remain challenging to discover. We integrated highquality phased assemblies from four new Papua New Guinea (PNG) genomes with 94 published assemblies of diverse ancestry to infer an archaic introgressed SV map. Introgressed SVs are overall enriched in genes (44%, n=1,592), including critical genomic disorder regions, and most abundant in PNG. We identify 11 centromeres likely derived from archaic hominins, adding unexplored diversity to centromere genomics. Pangenome genotyping across 1,363 samples reveals 16 candidate adaptive SVs, many associated with immune-related genes and their expression, in the PNG. We hypothesize that archaic SV introgression contributed to reproductive success, underscoring introgression as a significant force in human adaptive evolution. INTRODUCTIONEvidence from over a decade of research unequivocally supports interbreeding occurred between archaic hominins, such as Neanderthals(1-3) and Denisovan(4), and the ancestors of modern humans, likely through multiple points of contact over the past 100,000 years of human evolution (5, 6). Genomic studies have largely focused on using single-nucleotide variant (SNV) from diverse populations to establish patterns of archaic introgression in our genome. Modern humans in Eurasia today derive 2-5% (or 120-300 million base pairs [Mbp] per diploid genome) of their ancestry from archaic hominins, with the highest levels observed in Papua New Guinea (PNG)(5, 7). Despite the evidence of selection against deleterious archaic alleles in the human genome, some archaic sequences likely contributed to human phenotypic variation(8, 9). Consistent with these functional implications, many introgressed loci in our genome show signatures of positive selection. Some of those loci encompass candidate genes that are known to be functionally associated with differential gene expression, altitude, immunity, metabolism, and disease, highlighting contributions of introgressed alleles to the evolution of our species(10-16). Notwithstanding these discoveries, our understanding of the contribution of archaic introgression to human genomic variation and evolution remains far from complete due to the incomplete characterization of all classes of genetic variation. Structural variants (SVs), especially in complex loci, including segmental duplications (SDs) and centromeres(17-19), have been challenging to assess because of the highly fragmented nature of ancient DNA (~50 bp) and the near impossibility of systematically discovering SVs from such ancient DNA, especially in gene-rich regions associated with repeats(14).SVs, such as insertions, deletions, and inversions, contribute disproportionately to human genetic diversity by affecting more genomic sequences than SNVs and can significantly disrupt genes and regulatory elements, leading to relatively larger effects on gene expression and phenotype as defined by association studies (17, 20). Indeed, the effect size for this particular class has been estimated to be more than order of magnitude greater than single-nucleotide polymorphisms. In humans, many SVs have been strongly implicated in a variety of diseases, such as neurodevelopmental disorders (e.g., 22p11.2 deletion syndrome, 22q11.2DS)(20) and coronary heart diseases (LPA)(21). Conversely, human-specific SVs have been shown to play important roles in the adaptive evolution of our species, including the adaptations to diet( 22) and the expansion of human neocortex(23). Furthermore, several recent studies provided some of the first evidence for adaptive SV introgression (12, 14, 16) and reported novel protein-coding genes with positively selected sites within introgressed regions(14). Notably, these studies relied primarily on shortread sequencing data, with limited long-read data available, inadequately capturing the full spectrum of variations, particularly in complex loci, due to the intricate and repetitive nature of many SVs(17, 19, 21, 24). Therefore, advancements in data and inference approaches are still required for comprehensive analysis of SV evolution.Highly accurate long-read sequencing technologies have now made it possible to completely resolve complex repetitive regions in the human genome for the first time, including most SVs (17, 19, 21, 24, 25). Recent long-read sequencing efforts from the Human Pangenome Reference Consortium (HPRC)(21) and the Human Genome Structural Variation Consortium (HGSVC)(17) reveal that over 70% of SVs are inaccessible to short-read sequencing, with many novel SVs located in genes or regions</div