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Biomass burning and marine aerosol processing over the southeast Atlantic Ocean: a TEM single-particle analysis
No full textInternational audienceThis study characterizes single-particle aerosol composition from filters collected during the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) and CLoud-Aerosol-Radiation Interaction and Forcing: Year 2017 (CLARIFY-2017) campaigns. In particular the study describes aged biomass burning aerosol (BBA), its interaction with the marine boundary layer and the influence of biomass burning (BB) air on marine aerosol. The study finds evidence of BBA influenced by marine boundary layer processing as well as sea salt influenced by BB air. Secondary chloride aerosols were observed in clean marine air as well as in BB-influenced air in the free troposphere. Higher-volatility organic aerosol appears to be associated with increased age of biomass burning plumes, and photolysis or oxidation may be a mechanism for the apparent increased volatility. Aqueous processing and interaction with the marine boundary layer air may be a mechanism for the presence of sodium on many aged potassium salts. By number, biomass burning potassium salts and modified sea salts are the most observed particles on filter samples. The most commonly observed BC coatings are inorganic salts. These results suggest that atmospheric processes such as photolysis, oxidation and cloud processing are key drivers in the elemental composition and morphology of aged BBA. Fresh BBA inorganic salt content, as it has an important role in the particles' ability to uptake water, may be a key driver in how aqueous processing and atmospheric aging proceed
Selection for infectivity profiles in slow and fast epidemics, and the rise of SARS-CoV-2 variants
No full textInternational audienceEvaluating the characteristics of emerging SARS-CoV-2 variants of concern is essential to inform pandemic risk assessment. A variant may grow faster if it produces a larger number of secondary infections (“R advantage”) or if the timing of secondary infections (generation time) is better. So far, assessments have largely focused on deriving the R advantage assuming the generation time was unchanged. Yet, knowledge of both is needed to anticipate the impact. Here, we develop an analytical framework to investigate the contribution of both the R advantage and generation time to the growth advantage of a variant. It is known that selection on a variant with larger R increases with levels of transmission in the community. We additionally show that variants conferring earlier transmission are more strongly favored when the historical strains have fast epidemic growth, while variants conferring later transmission are more strongly favored when historical strains have slow or negative growth. We develop these conceptual insights into a new statistical framework to infer both the R advantage and generation time of a variant. On simulated data, our framework correctly estimates both parameters when it covers time periods characterized by different epidemiological contexts. Applied to data for the Alpha and Delta variants in England and in Europe, we find that Alpha confers a+54% [95% CI, 45–63%] R advantage compared to previous strains, and Delta +140% [98–182%] compared to Alpha, and mean generation times are similar to historical strains for both variants. This work helps interpret variant frequency dynamics and will strengthen risk assessment for future variants of concern
Mean-field BSDEs with jumps and dual representation for global risk measures
No full textInternational audienceWe study mean-field BSDEs with jumps and a generalized mean-field operator that can capture higher order interactions. We interpret the BSDE solution as a dynamic risk measure for a representative bank whose risk attitude is influenced by the system. This influence can come in a wide class of choices, including the average system state or average intensity of system interactions. Using Fenchel-Legendre transforms, our main result is a dual representation for the expectation of the risk measure in the convex case. In particular we exhibit its dependence on the mean-field operator
A COL5A2 In-Frame Deletion in a Chihuahua with Ehlers-Danlos Syndrome
No full textInternational audienceEhlers-Danlos syndrome (EDS) is a group of heterogeneous, rare diseases affecting the connective tissues. The main clinical signs of EDS are skin hyperextensibility, joint hypermobility, and skin fragility. Currently, the classification of EDS in humans distinguishes 13 clinical subtypes associated with variants in 20 different genes, reflecting the heterogeneity of this set of diseases. At present, variants in three of these genes have also been identified in dogs affected by EDS. The purpose of this study was to characterize the clinical and histopathological phenotype of an EDS-affected Chihuahua and to identify the causative genetic variant for the disease. The clinical examination suggested a diagnosis of classical EDS. Skin histopathology revealed an abnormally thin dermis, which is compatible with classical EDS. Whole-genome sequencing identified a heterozygous de novo 27 bp deletion in the COL5A2 gene, COL5A2:c.3388_3414del. The in-frame deletion is predicted to remove 9 amino acids in the triple-helical region of COL5A2. The molecular analysis and identification of a likely pathogenic variant in COL5A2 confirmed the subtype as a form of classical EDS. This is the first report of a COL5A2-related EDS in a dog
"Comment devient-on diabétique ? La construction identitaire des personnes diabétiques de type 2 au prisme de leurs parcours de santé et des dispositifs de prise en charge"
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A comparison study on patient-psychologist voice diarization
No full textInternational audienceConversations between a clinician and a patient, in natural conditions, are valuable sources of information for medical follow-up. The automatic analysis of these dialogues could help extract new language markers and speed up the clinicians' reports. Yet, it is not clear which model is the most efficient to detect and identify the speaker turns, especially for individuals with speech disorders. Here, we proposed a split of the data that allows conducting a comparative evaluation of different diarization methods. We designed and trained end-to-end neural network architectures to directly tackle this task from the raw signal and evaluate each approach under the same metric. We also studied the effect of fine-tuning models to find the best performance. Experimental results are reported on naturalistic clinical conversations between Psychologists and Interviewees, at different stages of Huntington's disease, displaying a large panel of speech disorders. We found out that our best end-to-end model achieved 19.5% IER on the test set, compared to 23.6% achieved by the finetuning of the X-vector architecture. Finally, we observed that we could extract clinical markers directly from the automatic systems, highlighting the clinical relevance of our methods
Particularités des anticorps de lama et autres camélidés et leurs intérêts thérapeutiques
No full textA few tens of millions of years have passed since they emerged, until 1993 and the discovery of single-domain antibodies (sdAbs or VHH) lacking light chains, also known as nanobodies, in llamas and other camelids. The reasons for their appearance are not yet fully elucidated, but there is no doubt that they should allow a remarkable adaptive immune response for these species of camelids (Camelus dromedarius and Camelus bactrianus), llamas and alpacas (Lama glama, Lama pacos and Lama guanicoe), vicuñas (Vicugna vicugna and Vicugna pacos) or cartilaginous fish, in which they are also found. Indeed, natural selection pressure has certainly allowed their emergence within various taxa, where they are found, circulating in the plasma, in various proportions. Their morphological and physico-chemical characteristics, namely their small size (~15kDa), their high affinity, their strong specificity, their low immunogenicity, their modularity, their simplicity of production, their stability and resistance to extreme environmental conditions, makes them interesting biotechnology tools. Their production, based on the immunization of camelids, and their selection via phage display techniques allows the manufacture of large antibody libraries at low cost. Currently under study and sometimes even under development, nanobodies have applications in various fields such as research, medicine and industry. Medical imaging tools, cancer therapy, early detection of Alzheimer's disease, development of vaccines, diagnostic tools, are all possibilities offered by nanobodies. Thus, these small molecules certainly have a promising future ahead of them.Il s'est écoulé quelques dizaines de millions d'années depuis l'émergence des anticorps conventionnels jusqu'à la découverte en 1993 des anticorps à domaines uniques (sdAbs ou VHH) dépourvus de chaînes légères, également connus sous le nom de nanocorps, chez les lamas et autres camélidés. Les raisons de leurs conditions d'apparition ne sont pas encore totalement élucidées, mais il ne fait aucun doute qu'ils doivent permettre une réponse immunitaire adaptative remarquable chez ces espèces de camélidés (Camelus dromedarius et Camelus bactrianus), de lamas et alpagas (Lama glama, Lama pacos et Lama guanicoe), de vigognes (Vicugna vicugna et Vicugna pacos), mais aussi de poissons cartilagineux, chez lesquels ils sont également présents. En effet, une pression de sélection a certainement permis leur émergence au sein de taxons variés, où ils sont retrouvés, circulants dans le plasma, en diverses proportions. Leurs caractéristiques morphologiques et physico-chimiques, à savoir leur petite taille (~15kDa), leur haute affinité, leur forte spécificité, leur faible immunogénicité, leur modularité, leur simplicité de production, leur stabilité et résistance à des conditions environnementales extrêmes, leur permettent de devenir des outils de biotechnologie intéressants. Leur production, basée sur l'immunisation de camélidés, et leur sélection via des techniques de « phage display », permet de produire de grandes bibliothèques d'anticorps, et à faible coût. Actuellement à l'étude, et parfois même en cours de développement, les nanocorps trouvent des domaines d'application dans les milieux de la recherche, la médecine et l'industrie. Outils d'imagerie médicale, thérapie contre le cancer, dépistage précoce et perspectives de traitement de la maladie d'Alzheimer, développement de médicaments et vaccins, outils diagnostics, sont autant de possibilités qui s'offrent aux nanocorps. Ces petites molécules ont indéniablement un avenir prometteur devant elles
Les hémosporidies des rapaces et corvidés en centres de soins : enquête épidémiologique 2018-2019 au centre d'accueil de faune sauvage de l’École vétérinaire d'Alfort (CHUV-FS)
No full textThe scientific interest in Hemosporidia is currently being reawakened, following, amongst others, the damages they have caused on wildlife, as well as the expanding role of wildlife hospitals in matters of avifauna rehabilitation. This study’s objectives were twofold: firstly, to compile a global overview of the epidemiological situation concerning hemoparastism in the raptors and corvids fostered in a wildlife hospital in Île-de-France; secondly, to identify potential key factors in the haemosporidian infestation and its transmission in those species, in order to propose relevant risk mitigation measures. Between May 2018 and May 2019, a transversal and monocentric study was conducted on birds sheltered at the wildlife hospital of the national veterinary school of Alfort, which included 37 raptors (6 species), mainly of peri-urban origins, and 150 corvids (4 species), mainly of urban origins. The analysis of the resulting blood smears allowed for the morphological identification of Hemosporodia and gave an estimate for the parasitemia. This study highlighted the presence of three genera of hemosporidia (Haemoproteus, Leucocytozoon and Plasmodium). The close release rates between infested and non-infested birds (72% of raptors, 35% of corvids) shows the weak clinical impact of hemoparasitism. Statistical analysis of the results demonstrated a positive association between juvenile corvids and Plasmodium sp. infection. Plasmodium infestation was particularly predominant in corvids, and was also more frequently implicated in cases of co-infestations. Though it was not statistically proven, Leucocytozoon seems to be infecting raptors more often than any other genera of hemosporidia. Results suggest that hemoparasitism in raptors and corvids in wildlife hospitals is a largely sub- clinical infestation, and has very little impact of the potential release of the birds. It is therefore crucial to determine the existence of vectors in wildlife hospitals, and to limit the risk of transmission during the rehabilitation period. Thus, it will allow for the implementation of risk management measures concerning vector control and will reduce the risk of dissemination of hemosporidies via released birds.Les hémosporidies bénéficient d'un regain d'intérêt à l'heure actuelle suite, entre autres, aux dommages qu'elles ont pu causer sur la faune sauvage et à l'importance croissante des centres de soin dans la réhabilitation de l'avifaune. Les objectifs de cette étude étaient de réaliser un état des lieux de la situation épidémiologique de l'hémoparasitisme touchant les rapaces et corvidés accueillis dans un centre de soins de la faune sauvage en Île-de-France, d'identifier de potentiels facteurs influençant l'infestation et sa transmission, afin de proposer des mesures adaptées de gestion du risque représenté par l'hémoparasitisme sur les rapaces et corvidés. Une étude transversale monocentrique était réalisée sur 37 rapaces (6 espèces) principalement d'origine péri-urbaine et 150 corvidés majoritairement d'origine urbaine (4 espèces) arrivés au Chuv- FS de l'EnvA entre mai 2018 et mai 2019. L'analyse des frottis a permit l'identification morphologique des hémosporodies et l'estimation de la parasitémie. Cette étude a mis en évidence trois genres d'hémosporidies (Haemoproteus, Leucocytozoon et Plasmodium). Le taux de relâché très proche parmi les infestés et non infestés (72% des rapaces, 35% des corvidés) montre la faible incidence clinique liée à l'hémoparasitisme. L'analyse statistique des résultats a montré une association positive entre les corvidés juvéniles et l'infection par Plasmodium sp., L'infestation à Plasmodium en particulier était prédominante chez les corvidés et était aussi plus fréquemment impliquée dans les cas de co-infestations. Bien que non démontré statistiquement, Leucocytozoon semblait infester plus fréquemment les rapaces que les autres genres d'hémosporidies. Les résultats suggèrent que l'hémoparasitisme chez les rapaces et corvidés en centre de soins est une infestation majoritairement subclinique influençant probablement peu le potentiel relâché des oiseaux. Il est donc important de déterminer la présence des vecteurs dans les centres de soin et le risque de transmission pendant la période de réhabilitation. Ceci permettra d'établir les mesures de gestion de ce risque sur la lutte antivectorielle et permettra de réduire le risque de dissémination des hémosporidies lors des relachés
Importance de l’analyse a priori des tâches effectivement proposées lors de la reprise d’une ingénierie didactique dans des classes ordinaires
No full textInternational audienceThis methodological oriented contribution is about the integration in two ordinaries school classes of a didactic engineering related to the subtraction, developed by Brousseau in the 80s. More specifically, this article focuses on the importance of a priori analysis of the tasks effectively proposed to students in the process of analyzing ordinary teaching/learning practices. Research has highlighted two key moments conditioning the engineering process: the first consisting in bringing out the mathematical proof of a result resulting from a subtraction, the second in using the proof to construct and give meaning to an operating algorithm. These two key moments are subject to different interpretations leading the teachers to modify the initially planned didactic environment and to propose tasks deviating from the basic situations. In this paper, we show the need for a stratum of a priori analysis of the tasks really proposed, a stratum intercaled between the epistemic a priori analysis of the didactic engineering and the a posteriori analysis of the contingency, and that, in order to understand the implementation of a didactic engineering in ordinary classes.Cette contribution d’orientation méthodologique porte sur l’intégration dans deux classes ordinaires d’école primaire d’une ingénierie didactique relative à la soustraction élaborée par Guy Brousseau dans les années 80. Il s’agit de porter l’accent sur l’importance de l’analyse a priori des tâches effectivement proposées aux élèves dans le processus d’analyse de pratiques ordinaires d’enseignement/apprentissage. La recherche a mis en évidence deux moments-clés conditionnant le déroulement de l’ingénierie : le premier consistant à faire émerger la preuve mathématique d’un résultat issu d’une soustraction, le second visant à utiliser la preuve pour construire et donner sens à un algorithme opératoire. Ces deux moments-clés font l’objet d’interprétations différentes conduisant les enseignantes à modifier le milieu didactique initialement prévu et à proposer des tâches s’écartant des situations fondamentales. Dans cet article, nous montrons la nécessité d’une strate d’analyse a priori des tâches effectivement proposées, strate s’intercalant entre l’analyse a priori épistémique de l’ingénierie didactique et l’analyse a posteriori de la contingence et ce, afin de comprendre la reprise d’une ingénierie didactique dans des classes ordinaires