447 research outputs found

    Detection of Phase Jumps of Free Core Nutation of the Earth and their Concurrence with Geomagnetic Jerks

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    We detected phase jumps of the Free Core Nutation (FCN) of the Earth directly from the analysis of the Very Long Baseline Interferometer (VLBI) observation of the Earth rotation for the period 1984-2003 by applying the Weighted Wavelet Z-Transform (WWZ) method and the Short-time Periodogram with the Gabor function (SPG) method. During the period, the FCN had two significant phase jumps in 1992 and 1998. These epochs coincide with the reported occurrence of geomagnetic jerks.Comment: 8 pages, 4 figure

    Modélisation et identification de modèles neuronaux pour les signaux EEG en épilepsie

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    - Le problème posé est de construire et identifier des modèles non linéaires permettant de simuler et d'interpréter physiologiquement les signaux EEG rencontrés en épilepsie. Un tel modèle, de type non linéaire, est présenté ainsi que deux techniques d'identification. La première est très simple et revêt un caractère qualitatif qui permet cependant d'explorer efficacement les différentes formes de signaux rencontrés. La deuxième est basée sur une méthode de simulation d'équations différentielles stochastiques et l'utilisation d'un filtrage de Kalman non linéaire

    Restoration of NK Cell Cytotoxic Function With Elotuzumab and Daratumumab Promotes Elimination of Circulating Plasma Cells in Patients With SLE.

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    Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease characterized by multiple cellular and molecular dysfunctions of the innate and adaptive immunity. Cytotoxic function of NK cells is compromised in patients with SLE. Herein, we characterized the phenotypic alterations of SLE NK cells in a comprehensive manner to further delineate the mechanisms underlying the cytotoxic dysfunction of SLE NK cells and identify novel potential therapeutic targets. Therefore, we examined PBMC from SLE patients and matched healthy controls by single-cell mass cytometry to assess the phenotype of NK cells. In addition, we evaluated the cell function of NK cells (degranulation and cytokine production) and the killing of B cell subpopulations in a B cell-NK cell in vitro co-culture model. We found that SLE NK cells expressed higher levels of CD38 and were not able to adequately upregulate SLAMF1 and SLAMF7 following activation. In addition, ligation of SLAMF7 with elotuzumab or of CD38 with daratumumab on SLE NK cells enhanced degranulation of both healthy and SLE NK cells and primed them to kill circulating plasma cells in an in vitro co-culture system. Overall, our data indicated that dysregulated expression of CD38, SLAMF1 and SLAMF7 on SLE NK cells is associated with an altered interplay between SLE NK cells and plasma cells, thus suggesting their contribution to the accumulation of (auto)antibody producing cells. Accordingly, targeting SLAMF7 and CD38 may represent novel therapeutic approaches in SLE by enhancing NK cell function and promoting elimination of circulating plasma cell

    Mesure de l'excitation et de l'inhibition dans le tissu neuronal en épilepsie par identification d'un modèle dynamique non linéaire d'activité EEG

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    Le problème posé est d'identifier un modèle réaliste physiologiquement pour interpréter les signaux EEG rencontrés en épilepsie. Ce modèle présente des non-linéarités, et son identification peut être envisagée suivant différentes approches. Celle qui est présentée passe par la minimisation d'une distance dans un espace de descripteurs, au moyen d'un algorithme évolutionnaire. Des résultats en simulation et sur signaux réels montrent que les valeurs identifiées permettent effectivement de dégager et d'interpréter certaines évolutions caractéristiques en début des crises

    Suivi de relation en temps et en fréquence dans les signaux SEEG épileptiques. Evaluation de deux estimateurs linéaires

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    Dans cet article, on s'intéresse au suivi de l'évolution en temps et en fréquence de la relation linéaire entre deux signaux non stationnaires (signaux EEG intracérébraux enregistrés chez des patients épileptiques). Un estimateur est proposé, basé sur la mesure du coefficient de corrélation linéaire entre les signaux de sous-bandes, optimisé pour le retard, et comparé à un estimateur de la fonction de cohérence (classiquement utilisé dans l'analyse du signal EEG). Les résultats obtenus sur signaux simulés montrent que l'estimateur proposé permet de réduire le biais, et la variance d'estimation. Sur signaux réels, ils permettent de mettre en évidence une différence, importante sur le plan de la physiopathologie, sur la corrélation des signaux durant l'activité intercritique (en dehors des crises) et durant l'activité critique (pendant les crises)

    SLAMF Receptor Expression Identifies an Immune Signature That Characterizes Systemic Lupus Erythematosus.

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    Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology, linked to alterations in both the innate and the adaptive immune system. Due to the heterogeneity of the clinical presentation, the diagnosis of SLE remains complicated and is often made years after the first symptoms manifest, delaying treatment, and worsening the prognosis. Several studies have shown that signaling lymphocytic activation molecule family (SLAMF) receptors are aberrantly expressed and dysfunctional in SLE immune cells, contributing to the altered cellular function observed in these patients. The aim of this study was to determine whether altered co-/expression of SLAMF receptors on peripheral blood mononuclear cells (PBMC) identifies SLE characteristic cell populations. To this end, single cell mass cytometry and bioinformatic analysis were exploited to compare SLE patients to healthy and autoimmune diseases controls. First, the expression of each SLAMF receptor on all PBMC populations was investigated. We observed that SLAMF1+ B cells (referred to as SLEB1) were increased in SLE compared to controls. Furthermore, the frequency of SLAMF4+ monocytes and SLAMF4+ NK were inversely correlated with disease activity, whereas the frequency SLAMF1+ CD4+ TDEM cells were directly correlated with disease activity. Consensus clustering analysis identified two cell clusters that presented significantly increased frequency in SLE compared to controls: switch memory B cells expressing SLAMF1, SLAMF3, SLAMF5, SLAMF6 (referred to as SLESMB) and circulating T follicular helper cells expressing the same SLAMF receptors (referred to as SLEcTFH). Finally, the robustness of the identified cell populations as biomarkers for SLE was evaluated through ROC curve analysis. The combined measurement of SLEcTFH and SLEB1 or SLESMB cells identified SLE patients in 90% of cases. In conclusion, this study identified an immune signature for SLE based on the expression of SLAMF receptors on PBMC, further highlighting the involvement of SLAMF receptors in the pathogenesis of SLE

    Relations entre les critères du module constant et de wiener

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    - Dans cet article nous présentons une nouvelle approche pour étudier la conjecture sur les relations entre les critères de Wiener et du module constant (CM). Notre proposition compris l'établissement d'une limite supérieure pour la fonction de coût CM, à partir d'un critère supervise, et la dérivation d'un rapport entre les minima des critères de Wiener et CM. Les résultats sont évalues par des simulations

    Recherche de reproductibilité dans les relations inter structures durant les crises d'épilepsie

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    Cet article s'inscrit dans le cadre de l'étude des signaux stéréoélectroencéphalographiques (EEG de profondeur) enregistrés lors de crises d'épilepsie. Il propose une méthode de mise en correspondance capable de quantifier, d'une crise à l'autre, les reproductibilités des relations inter-canaux estimées par la fonction de cohérence. Le travail est illustré sur des signaux construits à partir de différents scénarios décrivant un sous-type d'épilepsie (origine temporale). Les perspectives de ce travail sont liées, d'une part, à l'extraction de similarités dans l'évolution des relations qui s'établissent entre les structures cérébrales durant les crises et, d'autre part, à la mise en évidence de scénarios récurrents dans l'organisation de ces crises

    The genus <i>Elaphomyces </i>(<i>Ascomycota</i>, <i>Eurotiales</i>):a ribosomal DNA-based phylogeny and revised systematics of European 'deer truffles'

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    Elaphomyces (‘deer truffles’) is one of the most important ectomycorrhizal fungal genera in temperate and subarctic forest ecosystems, but also one of the least documented in public databases. The current systematics are mainly based on macromorphology, and is not significantly different from that proposed by Vittadini (1831). Within the 49 species recognised worldwide, 23 were originally described from Europe and 17 of these were described before the 20th century. Moreover, very recent phylogenetic treatments of the genus are mainly based on a few extra-European species and most common European species are still poorly documented. Based on an extensive taxonomic sampling mainly made in the biogeographically rich Cantabrian area (Spain), complemented with collections from France, Greece, Italy, Norway, Portugal and Sweden, all currently recognized species in Europe have been sequenced at the ITS and 28S of the rDNA. Combined phylogenetic analyses yielded molecular support to sections Elaphomyces and Ceratogaster (here emended), while a third, basal lineage encompasses the sections Malacodermei and Ascoscleroderma as well as the tropical genus Pseudotulostoma. Species limits are discussed and some taxa formerly proposed as genuine species based on morphology and biogeography are re-evaluated as varieties or forms. Spore size and ornamentation, features of the peridial surface, structure of the peridium, and the presence of mycelium patches attached to the peridial surface emerge as the most significant systematic characters. Four new species: E. barrioi, E. quercicola, E. roseolus and E. violaceoniger, one new variety: E. papillatus var. sulphureopallidus, and two new forms: E. granulatus forma pallidosporus and E. anthracinus forma talosporus are introduced, as well as four new combinations in the genus: E. muricatus var. reticulatus, E. muricatus var. variegatus, E. papillatus var. striatosporus and E. morettii var. cantabricus. Lectotypes and epitypes are designated for most recognised species. For systematic purposes, new infrageneric taxa are introduced: E. sect. Ascoscleroderma stat. nov., E. subsect. Sclerodermei stat. nov., E. subsect. Maculati subsect. nov., E. subsect. Muricati subsect. nov., and E. subsect. Papillati subsect. nov. Lastly, E. laevigatus, E. sapidus, E. sulphureopallidus and E. trappei are excluded from the genus and referred to Rhizopogon roseolus, Astraeus sapidus comb. nov., Astraeus hygrometricus and Terfezia trappei comb. nov. (syn.: Terfezia cistophila), respectively
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