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Bovine ampullary and isthmic epithelial spheroids: proteomic profile and physiological features for in vitro studies of gamete-oviduct interactions.
No full textInternational audienceAfter mating or insemination, spermatozoa reach the first part of the oviduct, known as the isthmus, where a subpopulation binds to the epithelial cilia, forming a reservoir. Then, spermatozoa migrate toward the ampulla, where additional interactions with cilia occur and fertilization takes place. Exploring sperm-oviduct interactions requires physiologically relevant in vitro models. Our goal was to characterize isthmic and ampullary epithelial spheroids in terms of cellular, proteomic and sperm binding properties. Spheroids measuring 100-150 µm in diameter, formed after a 3-day culture of pre-ovulatory oviduct mucosa fragments, were selected and analyzed for (i) epithelial, fibroblast and cilia markers by immunostaining, (ii) proteomic content by dia-PASEF nanoLC-MS/MS, and (iii) ability to interact with bull spermatozoa during a 6-h co-culture, assessed by confocal and scanning electron microscopy. Cells within both isthmic and ampullary spheroids showed positive immunostaining for cytokeratin and no staining for vimentin. Ampullary spheroids consistently exhibited a higher proportion of ciliated cells compared to isthmic spheroids (24.5 % vs 20 %; p < 0.05; variation coefficients among replicates of 15 and 11 %, respectively). A total of 6914 proteins were quantified, of which 1010 (14 %) were differentially abundant between isthmic and ampullary spheroids. Following co-culture, 95-97 % of bound spermatozoa were attached by their head to cilia of both spheroid groups. The density of bound spermatozoa was on average 33-45 % higher on ampullary compared to isthmic spheroids (p < 0.001). This study provides a well-differentiated oviduct epithelium model for in vitro investigations of gamete and embryo interactions with the oviduct
Multi-Step Sintering Process on Sol-gel Synthetized Lead-free BNT for Enhanced Temperature Stability of Relaxor Ferroelectric State and Energy Storage Properties
No full textInternational audienceBismuth sodium titanate (Bi₀.₅Na₀.₅TiO₃) is one of the most promising candidates for new dielectrics in energy storage applications. Our research is aimed at a better understanding of the properties of this material depending on the synthesis conditions, using different types of sintering process and using a modified citrate method to reach smaller grain size than with solid-state reaction. Using this synthesis method, we demonstrate that a high density of approximately 92% can be achieved at a low sintering temperature of 1050 °C by employing a multi-step sintering process to control the various stages of sintering and grain growth. This process also enabled us to synthesize samples with grain sizes three times smaller (approximately 0.606 µm) than those obtained through conventional sintering (approximately 1.829 µm). Our research also characterizes differences in electric properties by comparing permittivity. The results are more promising for multi-step sintering, independent of density. Finally, we observe a shift in the depolarization temperature, indicating a more stable relaxor phase of our Bi₀.₅Na₀.₅TiO₃ at 160 °C, compared to the typical 200 °C reported in the literature
Essais sur le rôle de la politique monétaire de la BEAC dans le développement économique de l’UMAC
No full textThe aim of this dissertation is to examine the effectiveness of the BEAC’s monetary policy and to discuss there forms that need to be implemented to strengthen its effectiveness. The first chapter analyzes the impact of monetary policy on inflation in the member states, and the foreign exchange reserves of the Central African Monetary Union (UMAC) using structural vector auto-regressive models. Our results show that during theperiod 2000-2022, BEAC’s monetary policy has no significant impact on the price dynamics of its member states. However, it has a significant impact on the dynamics of foreign exchange reserves of the Monetary Union .The second chapter focuses on determining the optimal level of precautionary reserves for CEMAC. Two models are used : (i) reserves holding costs precautionary model of Keungne and al (2024) and (ii) the social welfare optimization model of Drummond and Dhasmana (2008). Both models lead to the conclusion that during the period 2000-2022, BEAC does not have enough foreign exchange reserves to finance productive investments without compromising external stability. The third chapter examines the possibility of implementing a foreign exchange reserve accumulation strategy aimed at improving the productivity of UMAC economies in order to strengthen the effectiveness of its monetary policy using the model developed by Matsumoto (2022). Empirical results of the model calibrated using UMAC data and solved using the perfect foresight algorithm indicate that the implementation of this strategy depends on the magnitude of adverse shocks on the international liquidity of residents of the monetary union.L’objectif de ce travail est d’examiner l’efficacité de la politique monétaire de la BEAC, et de discuter des réformes à mettre en place pour renforcer son efficacité. Le premier chapitre analyse l’impact de la politique monétaire sur l’inflation des Etats membres, et les réserves de change de l’Union Monétaire de l’Afrique Centrale (UMAC) à l’aide de modèles vectoriels autorégressifs structurels. Les résultats obtenus montrent que sur la période 2000-2022, la politique monétaire de la BEAC n’a pas d’incidence significative sur la dynamique des prix de ses Etats membres. En revanche, elle a une incidence significative sur la dynamique des réserves de change sur la période 2008-2023.Le deuxième chapitre s’intéresse à la détermination du niveau optimal des réserves de précaution de l’UMAC. Deux modèles sont utilisés : (i) le modèle d’optimisation des coûts de détention des réserves de Keungne et al (2024), et le modèle d’optimisation du bien-être social de Drummond et Dhasmana (2008). Ces deux modèles indiquent que sur la période 2000-2022, la BEAC ne disposerait pas de suffisamment de réserves de change pour financer les investissements productifs sans compromettre la stabilité externe de sa monnaie. Le troisième chapitre examine la possibilité de mettre en place à la BEAC une stratégie d’accumulation des réserves de change visant à améliore la productivité des économies de l’UMAC afin de renforcer l’efficacité de sa politique monétaire à l’aide du modèle de Matsumoto (2022). Les résultats obtenus à partir du modèle calibré sur des données de l’UMAC et résolu à partir de l’algorithme de prévoyance parfaite "Perfect Foresight" insuggèrent que la mise en place de cette stratégie dépend de l’amplitude des chocs adverses sur la trésorerie internationale des agents économiques résidents
Toward a new ecosystem of musicological studies
No full textInternational audienceMusic is an essential part of European cultural and economic objectives. While this might seem to provide an opportunity for musicology, both music and the science that best represents it remain underrepresented in policy and scientific infrastructures. Part of the problem is the nature of musical artefacts themselves. Unlike tangible heritage fields such as archaeology and visual arts, musical heritage spans both tangible and intangible elements—scores, instruments, oral traditions, data, (recorded) sound—that can be utilized for both research and commercial purposes. The diverging viewpoints on music as an industry and music as a domain of research have resulted in the limited integration within European heritage and digital infrastructures of both music and musicology.In order to chart new and sustainable paths for the field, EarlyMuse has been launched as the first Cooperation in European Science and Technology (COST) Action devoted to historical musicology (https://earlymuse.eu). A principal aim of EarlyMuse’s four-year programme (2024-2026) is to define new paths for musicological research in Europe in the domains of education, publications, sources, performances, and policies. Nearly 300 researchers from 40 countries across Europe and beyond are sharing data, analyses, and ambitions to provide inspiration for shifting the scientific and cultural policies of the European Union and its partners. By analysing the institutional challenges and opportunities our field faces, we are identifying new ways in which the discipline can position itself to meet the demands of the future.In this presentation, we will illuminate the organisation of our Action and the results of our work so far. Our intention is to demonstrate that, despite the challenges of integrating musical heritage and data into European infrastructures, there are unprecedented opportunities for musicology—but we must be ready to seize them
Plantes enjouées en temps de crise ? Temporalités et imaginaires du robinier faux-acacia au sud-ouest de la France
No full textInternational audienceAs ongoing climate catastrophes exacerbate the vulnerability of forest ecosystems, human societies are readjusting their relationships with neighbouring trees, placing new and urgent expectations on some species. The unassuming Black Locust (Robinia pseudoacacia L.), an Appalachian species introduced in Europe ca 1620, is the subject of such uncomfortable reshufflings, involving conflicting paces and rhythms, infatuations, neglect and late reckonings. In conversation with literatures on vegetal geographies and more-than-human temporalities, the paper delineates the intertwined social-ecological dynamics and associated imaginaries of Black Locust in south-western France, focussing on three past socio-environmental crises: wildfires in the afforested ‘Landes de Gascogne’; the phylloxera crisis in the Bordeaux vineyards; and the recent winter storms of 1999 and 2009. Based on archival data and qualitative research, we identify in each configuration how the tree was framed in temporal narratives and imaginaries, relying on a musical analogy to investigate the social/ecological histories of the enrolment of a plant in times of crises. In so doing, the paper makes an argument for a better ‘hearing’ of plant rhythmicities to analytically grasp the potential disruptions -or revitalizations- of multispecies entanglements.A medida que las catástrofes climáticas exacerban la vulnerabilidad de los ecosistemas forestales, las sociedades humanas están reajustando sus relaciones con los árboles en sus vecindarios, colocando nuevas y urgentes expectativas en algunas especies. La modesta acacia negra (Robinia pseudoacacia L.), una especie de los Apalaches introducida en Europa alrededor de 1620, es objeto de estas incómodas reorganizaciones, que implican ritmos conflictivos, enamoramientos, abandono y ajustes de cuentas. En diálogo con la literatura sobre geografías vegetales y temporalidades más que humanas, el artículo delinea las dinámicas socioecológicas entrelazadas y los imaginarios asociados de la acacia negra en el suroeste de Francia, centrándose en tres crisis socioambientales pasadas: los incendios forestales en las forestadas Landes de Gascogne; la crisis de la filoxera en los viñedos de Burdeos; y las recientes tormentas invernales de 1999 y 2009. Con base en datos de archivo e investigación cualitativa, identificamos en cada configuración cómo el árbol se enmarcó en narrativas e imaginarios temporales, recurriendo a una analogía musical para investigar las historias socioecológicas del rol de una planta en tiempos de crisis. De este modo, el artículo aboga por una mejor comprensión de las ritmicidades de las plantas para comprender analíticamente las posibles disrupciones —o revitalizaciones— de los entrelazamientos multiespecíficos.Alors que des catastrophes climatiques en cours exacerbent la vulnérabilité des écosystèmes forestiers, les sociétés humaines réajustent leurs rapports avec les arbres voisins, imposant de nouvelles attentes urgentes à certaines espèces. Cet arbre discret, le robinier faux-acacia (Robinia pseudoacacia L.), une espèce des Appalaches introduite en Europe vers 1620, fait l’objet de remaniements inconfortables, dont des allures et rythmes contradictoires, des infatuations, de la négligence et des représailles tardives. Se trouvant entre les discours des géographies végétales et des temporalités plus qu’humaines, cet article délinée les dynamiques socio-écologiques entremêlées et les imaginaires associées du robinier faux-acacia au sud-ouest de la France et se focalize sur trois crises socio-environnementales passées : incendies dans la région reboisée des Landes de Gascogne, la crise de phylloxéra dans les vignes de Bordeaux ainsi que les orages d’hiver récents datant de 1999 et de 2009. Sur la base des données d’archives et des recherches qualitatives, nous identifions dans chaque configuration comment cet arbre a été conçu au sein des narrations et des imaginaires temporales, s’appuyant sur une analogie musicale pour étudier les histoires sociales/écologiques de l’inscription des plantes en temps de crises. Cela faisant, l’article argumente l’importance d’une meilleure « écoute » des rythmicités végétales pour saisir analytiquement les perturbations potentielles, ou revitalisations, des enchevêtrements multi-espèces
L’opéra de cour en France (XVIIe-XVIIIe siècle) : goût, espaces, pratiques
No full textKnowledge of French opera has grown considerably in recent decades, thanks to numerous research projects that have produced seminal works. However, it must be noted that it is the corpus of the Académie Royale de Musique, an institution closely linked to the birth and development of the genre, that has attracted the most attention from researchers.At a time when research is increasingly concerned with cultural venues outside Paris, this publication, the result of an international symposium held at the Centre de Musique Baroque de Versailles in June 2023, seeks to examine opera production beyond the Académie Royale de Musique, focusing on court circles. Were the courts merely showcases for the repertoire of the Paris Opera? Were they not also, at the prince’s instigation, a unique place of creation or recreation? The chronological scope of our work runs from 1639, the year Mazarin, who imported Italian opera to France, began his ministry, to 1791, the year Parisian theatres lost their privileges. Although the period covered is broad, the publication seeks to highlight points of convergence that characterize what would then emerge as court opera, a spectacle specially produced at court and for the court.La connaissance de l’opéra français s’est considérablement enrichie au cours des dernières décennies, grâce à de nombreux projets de recherche donnant lieu à des travaux de référence. Toutefois, force est de constater que c’est davantage le corpus de l’Académie royale de musique, institution étroitement liée à la naissance et au façonnement du genre, qui a attiré l’attention des chercheurs.À l’heure où la recherche s’intéresse de plus en plus aux lieux culturels en dehors de Paris, le présent numéro, fruit d’un colloque international tenu au Centre de musique baroque de Versailles en juin 2023, souhaite interroger la production d’opéras au-delà de l’Académie royale de musique, en se penchant sur les milieux curiaux. Les cours n’ont-elles été que des écrins à la représentation du répertoire de l’Opéra de Paris ? N’ont-elles pas aussi été, par la volonté du prince, un lieu de création ou de recréation singulier ? L’empan chronologique de notre publication court de 1639, année du début du ministère de Mazarin, importateur de l’opéra italien en France, à 1791, année de la perte des privilèges des salles de spectacles parisiennes. Bien que la période observée soit large, ce collectif souhaite mettre en évidence des points de convergence permettant de caractériser ce qui apparaîtrait alors comme un opéra de cour, un spectacle spécialement produit à la cour et pour la cour
A Noise‐Tolerant Inference Procedure for Quasi‐Monte Carlo Likelihood Estimation of a Joint Model for Multiple Longitudinal Markers and Competing Risks
No full textInternational audienceDespite increasingly widespread use, complex joint models for longitudinal and survival data can be difficult to estimate. Notably, this could be due to the computation of the intractable integral over random effects involved in the likelihood and whose dimensionality increases with the number of shared random effects. In this article, we propose approximating the integral over random effects through a Quasi‐Monte Carlo (QMC) approach combined with a noise‐tolerant Quasi‐Newton algorithm to consider the likelihood randomness induced by the QMC framework. From a simulation study, we demonstrate the suitability of the noise‐tolerant Quasi‐Newton algorithm to estimate the parameters of a shared random‐effect joint model for two longitudinal markers in the presence of two competing events. The noise‐tolerant Quasi‐Newton algorithm is also compared with a Quasi‐Newton algorithm with common draws in the QMC approach that showed good performance. Finally, we illustrate the interest of the noise‐tolerant Quasi‐Newton algorithm on kidney transplantation data. We jointly modeled the evolution of serum creatinine and donor‐specific antibody immunization, as well as their associations with the cause‐specific risks of graft failure and death with a functioning graft, using data from the French prospective and observational DIVAT cohort of kidney transplant recipients. The proposed noise‐tolerant inference procedure for QMC likelihood estimation is shown to be relevant for estimating a joint model with multiple longitudinal markers and competing risks