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Therapeutic Plasma Exchange for Severe Optic Neuritis in a Region with a High Prevalence of Neuromyelitis Optica
No full textInternational audienceIntroduction: The treatment of severe optic neuritis (ON) is an emergency, and the role of therapeutic plasma exchange (PLEX) is still debated. The objective of this study was to evaluate the efficacy of the initial combination of parenteral corticosteroid therapy with therapeutic PLEX for the treatment of severe ON. This was a retrospective cohort study conducted between January 1998 and January 2023.Methods: Therapeutic PLEX was initiated concomitantly with intravenous corticosteroid therapy. The etiological diagnosis of ON was specified as follows: neuromyelitis optica, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and multiple sclerosis. Sixty-five eyes (74.7%) underwent therapeutic PLEX, and 22 eyes (25.3%) received corticosteroid therapy alone.Results: The mean time to treatment was 7.9 ± 11 days. At 1 year, the mean visual acuity of plasmapheresis patients was 5/10, and that of non-plasmapheresis patients was 1.5/10 (p = 0.008). Five (8.1%) eyes in the PLEX group and 7 (31.8%) eyes in the group treated with corticosteroids alone remained completely blind (p = 0.005). The retinal nerve fiber layer and ganglion cell layer thickness were greater in the PLEX group than in the group treated with corticosteroids alone, 74 ± 23.1 μm versus 59.7 ± 19.3 μm and 24.7 ± 4.3 μm versus 23.3 ± 5.4 μm, respectively. MOGAD and multiple sclerosis patients had the best final visual acuity, 6/10 and 10/10, respectively (p = 0.01). No serious incidents were observed.Conclusion: This is the largest series of severe ON observed in an Afro-descendant population and treated concomitantly with therapeutic PLEX and systemic corticosteroid therapy at the acute phase. Our study confirms the efficacy of therapeutic PLEX in treating severe ON
Igneous apatite geochemistry indicates early cratonization of continents
No full textInternational audienceProcesses and mechanisms accounting for the stabilization of Archean (4.0–2.5 Ga) continental crust remain a matter of debate. Over the last decades, major efforts have been made to determine the chemical and isotopic composition of rocks belonging to the Tonalite-Trondhjemite-Granodiorite (TTG) suite, i.e. those forming the bulk of Archean continental crust, as well as late-Archean sanukitoids, the typical marker of cratonization. The extensive use of zircon elemental and isotopic signatures has indisputably been an unrivalled source of information; yet it has also biased interpretations through the prism of a single mineral, hence not reflecting the whole geological history of these magmas. To extend our understanding of early continent stabilization, a pivotal aspect of Earth’s evolution, a fresh perspective is necessary. Here, we present in-situ analyses of igneous apatite, Ca5(PO4)3(OH,Cl,F), from Archean granitoids exposed in the eastern Kaapvaal craton for major/trace elements and U–Pb/Sr isotopes. The trace element signatures of these apatite crystals, with a clear enrichment in LREE and an elevated LREE/HREE, resemble that of apatite from sanukitoids and Phanerozoic I-type granites, a signature which can be blurred at the whole-rock scale. We interpret this signature as indicating that the studied granitoids are formed via interaction between (i) a TTG melt, formed via partial melting of a subducting oceanic crust and (ii) a mantle component, causing chemical depletion of the mantle domain involved and thus production of long-lived and stable lithospheric keels pivotal in the long-term preservation of Archean lithosphere at the Earth’s surface. Therefore, the identification of this signature—in igneous apatite from Paleo to Meso-Archean TTGs of the eastern Kaapvaal—indicates an early onset of cratonization in this region
On the adjoint state method for the gradient computation in full waveform inversion: a complete mathematical derivation for the (visco-)elastodynamics approximation
No full textInternational audienceHigh-resolution seismic imaging at all scales using full waveform inversion is now routinely used in the industry and in the academy. One key element for the success of this approach is a numerical method, named adjoint state method, originally designed for optimization problems constrained by partial differential equations, a category to which full waveform inversion belongs. This method provides an efficient way to compute the gradient of the full waveform inversion misfit function, which is the most computationally demanding task in the implementation of full waveform inversion. While well known, the complete and rigorous mathematical derivation of the adjoint state method for full waveform inversion remains missing in the scientific bibliography. The aim of this study is to remedy this lack. The derivation is performed in general settings, that is in the elastodynamics approximation, with and without considering viscosity. Through the calculus, the mechanism of the adjoint state strategy makes clear the connection between the incident and adjoint fields, especially regarding their initial and boundary conditions. The impact of introducing the viscosity is carefully analysed. The resulting gradient formulas are analysed and shown to be consistent with already published ones. The generic approach which is adopted also makes it possible to derive misfit function gradients with respect to other quantities than the subsurface mechanical parameters, for instance with respect to the initial or the boundary conditions, which could be of interest for specific applications where the reconstructed parameters are not only volumetric mechanical parameters but boundary parameters or initial field values
Flexibilité de la régulation émotionnelle et paranoïa : une étude en journal quotidien
No full textInternational audienceLa flexibilité de la régulation émotionnelle (RE) joue un rôle clé dans l’adaptation aux situations changeantes et pourrait influencer la survenue et le maintien des pensées paranoïaques. Des études suggèrent que les individus présentant une propension à la paranoïa ont des difficultés à adapter leurs stratégies de RE au contexte, utilisant de manière rigide des stratégies inadaptées ou inefficaces. Toutefois, la flexibilité en matière de RE en lien avec la paranoïa en vie quotidienne reste peu explorée. Cette étude utilise une méthode du type journal quotidien sur 14 jours afin d'examiner le lien entre les trois composantes de la flexibilité de la RE (sensibilité au contexte, répertoire de stratégies, et feedback) et la paranoïa dans la population générale. Les participant.es (cible N = 300 participants) seront recruté.es via la plateforme Prolific et répondront quotidiennement à des questionnaires évaluant leur état émotionnel, leur perception du contexte (interne et externe), leurs stratégies de RE et leur efficacité, ainsi que leur niveau de paranoïa. Les données seront analysées via des modèles multiniveaux sous R pour tenir compte de la structure hiérarchique des mesures répétées. Nous anticipons qu’une sensibilité contextuelle limitée, un recours restreint aux stratégies de RE, une faible variabilité dans leur mise en œuvre ainsi qu’une persistance dans l’utilisation de stratégies inefficaces contribueront à la paranoïa. Ces résultats permettront d’affiner les modèles de la flexibilité de la RE dans la psychose et d’orienter les interventions ciblant l’adaptation émotionnelle afin de réduire les pensées paranoïaques
Directed searches for gravitational waves from ultralight vector boson clouds around merger remnant and galactic black holes during the first part of the fourth LIGO-Virgo-KAGRA observing run
No full textInternational audienceWe present the first directed searches for long-transient and continuous gravitational waves from ultralight vector boson clouds around known black holes (BHs). We use LIGO data from the first part of the fourth LIGO-Virgo-KAGRA observing run. The searches target two distinct types of BHs and use two new semicoherent methods: hidden Markov model (HMM) tracking for the remnant BHs of the mergers GW230814_230901 and GW231123_135430 (referred to as GW230814 and GW231123 in this study), and a dedicated method using the Band Sampled Data (BSD) framework for the galactic BH in the Cygnus X-1 binary system. Without finding evidence of a signal from vector bosons in the data, we estimate the mass range that can be constrained. For the HMM searches targeting the remnants from GW231123 and GW230814, we disfavor vector boson masses in the ranges and eV, respectively, at 30% confidence, assuming a 1% false alarm probability. Although these searches are only marginally sensitive to signals from merger remnants at relatively large distances, future observations are expected to yield more stringent constraints with high confidence. For the BSD search targeting the BH in Cygnus X-1, we exclude vector boson masses in the range eV at 95% confidence, assuming an initial BH spin larger than 0.5
Validation of a 2D/3D shape-matching method for estimating shoulder kinematics after reverse total shoulder arthroplasty using biplane radiographs
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Sédimentologie et enregistrement sédimentaire du Crétacé supérieur du Haut Atlas occidental Marocain
No full textInternational audienceLate Cretaceous sediments frequently record the paleoenvironmental and paleogeographic changes, which precede the Tertiary Alpine orogeny. The age of the Late Cretaceous deposits of the Moroccan Western High Atlas, has been refined thanks to few paleontological findings and to chemostratigraphical (13C) correlations. Coniacian and Santonian shallow marine deposits are dominated by the development of eustacy-controlled carbonate shelves, whereas Campanian and Maastrichtian deposition recorded mainly clastic deposits showing important facies and thickness variability, suggesting a tectonic instability. The appearance of sandstone beds and the fragmentation of the basin in the middle(?) Santonian (≈ 84 Ma) are interpreted as a result of a mild tectonic event. A significant tectonic event of Late Campanian age (≈ 77-74 Ma) is marked by the deposition of 50-100m-thick nearshore sandstones, by clastic dykes and mild angular unconformities in the South and by a probable widespread hiatus to the North. The latter area may have been uplifted by at least a few tens of meters. A new, major tectonic event of middle(?) Maastrichtian age (≈ 70 Ma) is marked, specially to the South and West of the study area, by deposition of up to 300 m-thick shallow marine sandstones, associated with slumps, breccias, clastic dykes and erosions. The absence or reduction of Paleocene deposits in the study area seems to be rather related to eustatic low sea level
Electrodeposition of Bismuth doped Perovskite for Photovoltaic Application
No full textInternational audienceElectrodeposition was investigated as a substitute technology to deposit the perovskite active layers in large area solar cells. This method involves growing perovskite crystals from a metal or metal oxide layer that had first been electroplated. A schematic representation of the electrodeposition process and subsequent conversion steps is shown in Figure 1. This technology offers a low-cost approach that produces smooth and uniform layers over large areas. Additionally, the process is conducted under ambient conditions, avoiding the need for a glove box. It’s also environmentally friendly, as no toxic solvents are required to stabilize or enhance the morphology of the layers. Finally, the electrodeposition is easy to scale up and proven to improve the interfaces (and thereby the charge transfer) between the layers.In this study we propose to try and use the electrodeposition protocol developed in the laboratory [1,2,3,4] with the addition of bismuth as a “doping agent” of the traditional MAPbI3 perovskite. Bismuth was introduced into the conversion bath as a precursor, partially substituting lead. This approach was motivated by efforts to reduce lead and previous evidence [5,6] suggesting that bismuth doping improves the solar cells stability. However, the former studies focused on cells processed via spin coating or drop casting, not electrodeposition. We investigated how varying the MAI:BiI3 ratio in the conversion bath affected the properties of the electrodeposited devices. Even at very low ratios, the microstructure, optical properties, chemical properties, bandgap energy, crystallinity, and stability of the perovskite were deeply impacted by the presence of the Bi. It also strongly affects the photovoltaic performance of the electrodeposited solar cells. Moreover, these parameters not only depend on the amount of Bi precursor in the bath, but also on the conversion time, suggesting a complex formation of the structures.In conclusion, while the addition of bismuth in MAPI perovskites is generally associated with reduced PCE, our study demonstrates that it can also offer interesting advantages. We demonstrate that with a specific amount of bismuth, the PCE remains comparable to that of MAPbI3, but with a stability significantly enhanced. A key result is the experimental evidence that Bi-doped photovoltaic cells remain functional even after 1000 hours of aging at 90% relative humidity and 30°C, even without any encapsulation
Influence de la musique sur les apprentissages précoces chez le nourrisson
No full textMusic, like language, is omnipresent in the environment from birth, appearing in a variety of forms. This thesis explores the effects of music on infants' cognitive abilities, with a particular focus on lexical development and visual recognition.To investigate these effects, an initial interventional study was conducted in a nursery (Chapter 2), comparing the impact of musical interventions with that of motor interventions on lexical development. The results show a significant and positive effect of musical intervention on vocabulary growth.Next, the influence of musical familiarity on visual recognition memory (faces andabstract patterns) was examined. Between 9 and 12 months, infants displayed signs of visual recognition memory and sensitivity to the type of music. However, no significant effect was observed between 18 and 24 months (Chapter 3, Studies 1 and 2). Conversely, for abstract patterns, infants aged 9 to 12 months showed no signs of memory (Chapter 3, Study 3).Finally, a control study explored whether this effect was specific to music or also applied to the auditory environment in general, using familiar and unfamiliar language with the same abstract patterns (Chapter 3, Study 4).Taken together, the results confirm that music can have a significant impact on thedevelopment of certain cognitive abilities.In the final chapter (Chapter 4), we discuss the potential of music as a tool for stimulating language. Overall, this thesis opens up new avenues for future research into the effects of music, particularly in infants.La musique, à l’instar du langage, est omniprésente dans l’environnement dès la naissance, sous des formes variées. Cette thèse explore les effets de la musique sur les capacités cognitives des nourrissons, en s’intéressant particulièrement au développement lexical et à la reconnaissance visuelle.Pour répondre à ces questions, une première étude interventionnelle a été réalisée en crèche (chapitre 2), comparant les effets d’interventions musicales à ceux d’interventions motrices sur le développement lexical. Les résultats révèlent un effet significatif et positif des interventions musicales sur l’augmentation de la taille du vocabulaire. Dans un second temps, l’influence de la familiarité musicale sur la mémoire de reconnaissance visuelle (visages et motifs abstraits) a été étudiée. Entre 9 et 12 mois, les nourrissons montrent des signes de mémoire de reconnaissance visuelle, avec une sensibilité au type de musique, bien qu’aucun effet significatif ne soit observé entre 18 et 24 mois (chapitre 3, études 1 et 2). En revanche, pour les motifs abstraits, les nourrissons âgés de 9 à 12 mois ne manifestent pas de signe demémorisation (chapitre 3, étude 3). Enfin, une étude contrôle a exploré si cet effet est spécifique à la musique ou s’il s’applique également à l’environnement sonore en général, en utilisant une langue familière et non familière avec les mêmes motifs abstraits (chapitre 3, étude 4).L’ensemble des résultats confirment que la musique peut avoir un impact significatif sur le développement de certaines capacités cognitives.Dans le dernier chapitre (chapitre 4), nous discutons du potentiel de la musique comme outil de stimulation du langage. L’ensemble de cette thèse ouvre des nouvelles perspectives pour de futures recherches sur les effets de la musique notamment chez le nourrisson