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Study of the dielectric non-linearities in 0.5(Ba0.7Ca0.3TiO3)–0.5(BaZr0.2Ti0.8O3) thin film
No full textInternational audienceThe high permittivity of relaxor ferroelectrics make them ideal for energy storage applications. Relaxors exhibit polar nanoregions (PNRs), clusters in which the polarization is randomly oriented in absence of electric field. As for conventional ferroelectrics, the polar entities (PNRs and ferroelectric domain walls) contribute to the macroscopic dielectric properties in relaxors. Due to their non-linear response, they exhibit specific dielectric behaviors, even below the coercive field. Here, we study the influence of the frequency of the AC measuring signal and the number of subcoercive field cycles on the dielectric response in a BCTZ relaxor thin film. In addition to the first harmonic response, i.e. conventional impedance spectroscopy, the third harmonic response is also measured. In the studied thin film, pinching of the hysteresis loop is observed. We show that the observed pinching of the ferroelectric hysteresis loop is strongly correlated with the presence of PNRs, based on the following observations.The measurements reveal that the pinching of the hysteresis loop, characterized by a phase angle of the third harmonic close to −270°, is stronger for low frequencies. The frequency sensitivity of the response strengthens the interpretation that this pinching may be related to PNRs. When repeating the measurement for a fixed frequency, the first harmonic response is almost unaffected whereas the pinched response progressively disappears and the typical relaxor response is obtained. This indicates that PNR contributions to impedance response of the system can be modulated by subcoercive low field cycling. First Order Reversal Curves (FORC) confirm the presence of a pinched hysteresis loop. When repeating the FORC measurement a second time, the distribution drastically changes and corresponds to a soft ferroelectric, with an asymmetric Preisach plane. This asymmetry of the Preisach plane is confirmed by a proposed novel measurement strategy: unipolar impedance measurements
Avez-vous déjà vu : le Jamais-Vu ?: Avez-vous déjà vu : le Jamais-Vu ?
No full textArticle de vulgarisation d'une publication originale : O’Connor A.R., et al., Déjà Vu and other dissociative states in memory. Memory, 2021. DOI : 10.1080/09658211.2020.1727519. Accès libre sur HAL (pdf).« table-table-table-table-table-table-table-table-table-table-table ». Avez-vous déjà répété un mot tant de fois qu’il finit par paraître particulier, comme étrange, presque vide de sens ? Imaginez écrire le mot « table » encore et encore, jusqu’à ce qu’il ne soit plus qu’une série de lettres sans logique, comme un code secret que vous ne parvenez plus à déchiffrer. Ce sentiment déconcertant de voir l’ordinaire devenir inconnu porte un nom : le Jamais-Vu. Ce phénomène, qui intrigue scientifiques et psychologues, vient d’être étudié en laboratoire. Il a valu aux auteurs et autrices de cet article un Ig Nobel, un prix aux recherches qui font rire… puis réfléchir »
A Trans and Queer Discursive Approach to Gender Diversity and Misgendering in the Transgender and Gender Diverse Population: Queering a Study for ICD-11
No full textInternational audienceProducing knowledge about transgender and gender-diverse (TGD) individuals is a core public health strategy challenge. Yet several systemic limitations arise, notably the exclusion or exploitation of TGD individuals by research systems reproducing systemic discrimination by embedding social norms as self-evident facts of nature. This is particularly worrying in biomedical research, and contributes to the invisibilization of participants’ gender diversity. This trans research illustrates methodological challenges through queering an earlier study by focusing on misgendering as a discursive element. We based our work on discursive materials reported by TGD participants in an ICD-11 study on gender incongruence. We used network analyses to illustrate potential differences between declared gender identity and discourse practices. Our results highlight a gap between declared gender identity and discourse practices, bringing the number of non-binary participants in the sample from 15 (20.8%) to 36 (50.0%). Moreover, misgendering and the use of derogatory terms are more common toward gender-diverse individuals. Sexual orientation shows a similar trend. This study reveals the reproduction of social norms within research processes and medical knowledge, as well as how, from an individual perspective, their non-compliance seems to be a key factor in TGD individuals’ experience. By providing this simple methodological example, we hope to promote better integration of gender and its various dimensions into biomedical and public health research
Sur les traces des lecteurs : commande et acheminement des journaux en province (fin XVIIIe-XIXe siècles)
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Optimization of artificial multifunctional K0.5Na0.5NbO3 - CoFe2O4 ceramics
No full textInternational audienceLead and rare earth-free (1-x)K0.5Na0.5NbO3– (x)CoFe2O4 composites (where x = 0.05, 0.10 and 0.20), consisting of ferroelectric K0.5Na0.5NbO3 (KNN) matrix and ferromagnetic CoFe2O4 (CFO) nano-inclusions, were densified via spark plasma sintering (SPS) to develop multifunctional materials. X-ray diffraction (XRD) confirmed the absence of secondary phases. High resolution scanning electron microscopy (HR-SEM) revealed dense microstructures, with increasing CFO grain size at higher CFO content. Energy dispersive X-ray spectroscopy (EDS) mapping and scattered scanning near-field optical microscopy (s-SNOM) confirmed CFO distribution in KNN matrix. Ferroelectric hysteresis loops demonstrated ferroelectricity in all composites. Dielectric measurements howed relaxation behavior with increasing losses for higher CFO content. Magnetic analysis at room temperature indicated a dominant ferromagnetic behavior, with superparamagnetic and diamagnetic contributions from CFO and KNN, respectively. Our complete full knowledge studies functionalities will be helpful to build ceramics architectures suitable for magneto-electric propertie
Record of trace organic contaminants in a river sediment core: From historical wastewater management to historical use
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Entre production, circulation et consommation : diversité de la céramique très décorée Périgourdine.
No full textInternational audienceIn the Dordogne, highly-decorated ceramics are as conspicuous as they are discreet: featuring a wide variety of decorations and sometimes of great technical complexity, they can always be seen surreptitiously on Périgord medieval sites. This type of pottery is also surprisingly short-lived, appearing suddenly at the beginning of the 14th century, without any real technical precursors, before disappearing at the end of the same century.The increase in preventive archaeology operations in this area has led to recent discoveries, providing new data on this ceramic category. The aim of this poster is therefore to present an overview of the current state of knowledge, while exploring two main avenues of investigation. Firstly, it will present the production of the Sainte-Catherine workshop, a dispensary discovered by chance in Bergerac in the 1970s. Emphasis will be placed on the specific features of this highly decorated pottery, in particular the pastes used, the surface treatments and the decorative registers. The influence of this workshop will also be explored through local discoveries. In addition to the production aspect, the items found at consumption sites in the Périgord region will be discussed and characterised in order to appreciate their technical and decorative aspects. The sum total of this documentation will enable us to conjecture how the typo-technological and stylistic differences in highly decorated ceramics reveal the different origins of the pottery.En Dordogne, la céramique très décorée est autant ostentatoire que discrète : présentant des décors très variés et parfois d’une grande complexité technique, elle est toujours observée furtivement sur les sites médiévaux périgourdins. Cette céramique surprend également par sa chronologie réduite : elle apparait subitement au début du XIVe siècle, sans véritables précurseurs techniques, avant de disparaître à la fin de ce même siècle.La multiplication des opérations d’archéologie préventive au sein de ce territoire a permis de récentes découvertes, apportant de nouvelles données sur cette catégorie céramique. Ce poster a donc pour ambition de présenter un état des connaissances, tout en explorant deux principales pistes de réflexion. Il s’agira tout d’abord de présenter la production de l’atelier Sainte-Catherine, une officine découverte fortuitement à Bergerac dans les années 70. L’accent sera mis sur les spécificités de cette céramique très décorée, en particulier sur les pâtes utilisées, les traitements de surfaces et les registres décoratifs. Le rayonnement de cet atelier sera également questionné à travers les découvertes locales. Au-delà de cet aspect productif, les éléments retrouvés sur les sites de consommations périgourdins seront abordés et caractérisés afin d’en apprécier l’aspect technique et décoratif. La somme de cette documentation permettra de conjecturer comment les différences typo-technologiques et stylistiques de la céramique très décorée révèlent des sous-entités régionales au sein même de la Dordogne
Prédiction des scores d'utilité EQ-5D-3L de patients transplantés rénaux à partir de données cliniques : une étude de cohorte
No full textInternational audienceObjectives: Modelling health-state utility values (HSUVs) from clinical data offers a means to conduct retrospective cost-effectiveness analyses using clinical studies that did not collect direct HSUV measures. Such studies can support the efficient allocation of resources in kidney transplantation (KT). We aim to model KT recipients' EQ-5D-3L HSUVs using routinely collected clinical data.Methods: From a French observational multicentric prospective cohort, we included 2,787 adult recipients of a first or second single renal graft transplanted between January 2014 and December 2021 who completed 5,679 EQ-5D-3L questionnaires post-KT, from which the HSUVs were calculated. Considering two time periods before and after 1-year post-KT, we estimated a linear mixed effect model (LME), a mixed adjusted limited dependent variable mixture model, and beta and two-part beta mixed models. We compared their predictive performances in terms of precision and calibration.Results: In each model, recipient age, female sex, higher body mass index, presence of comorbidities and time spent on dialysis prior to KT were associated with lower HSUVs. The predicted HSUVs increased during the first year post-KT before slowly decreasing afterwards. The two-part beta mixed model resulted in the most precise predictions but showed poor calibration. The LME was associated with better calibration than the other models.Conclusions: Our study illustrates the importance of estimating longitudinal predictive algorithms to consider possible time variations in HSUVs. We provide an online calculator for predicting the HSUVs of KT recipients over time. Future studies in international cohorts are important to support the external validity of our results.Objectifs: La modélisation des scores d'utilité à partir de données cliniques permet de réaliser des analyses coût-efficacité rétrospectives à partir d'études cliniques qui n'ont pas recueilli de mesures directes des scores d'utilité. De telles études peuvent contribuer à l'allocation efficace des ressources dans le domaine de la transplantation rénale. Notre objectif est de modéliser les scores d'utilité EQ-5D-3L des receveurs de greffe rénale à partir de données cliniques collectées en routine.Méthodes: À partir d'une cohorte prospective multicentrique observationnelle française, nous avons inclus 2 787 adultes receveurs d'un premier ou deuxième greffon rénal unique transplanté entre janvier 2014 et décembre 2021, qui ont rempli 5 679 questionnaires EQ-5D-3L post-greffe à partir desquels les scores d'utilité ont été calculés. En considérant deux périodes de temps avant et après 1 an post-greffe, nous avons estimé un modèle linéaire à effets mixtes (LME), un modèle mixte ajusté à variables dépendantes limitées (ALDVMM), et des modèles mixtes beta et beta en deux parties. Nous avons comparé leurs performances prédictives en termes de précision et de calibration.Résultats: Dans chaque modèle, l'âge du receveur, le sexe féminin, un indice de masse corporelle plus élevé, la présence de comorbidités et le temps passé en dialyse avant la greffe étaient associés à des scores d'utilité plus faibles. Les scores d'utilité prédits ont augmenté au cours de la première année suivant la greffe avant de diminuer lentement par la suite. Le modèle mixte beta en deux parties a permis d'obtenir les prédictions les plus précises, mais a montré une mauvaise calibration. Le modèle LME a été associé à une meilleure calibration que les autres modèles.Conclusions: Notre étude illustre l'importance d'estimer des algorithmes prédictifs longitudinaux pour prendre en compte les potentielles variations temporelles des scores d'utilité. Nous fournissons un calculateur en ligne pour prédire les scores d'utilité au cours du temps des bénéficiaires de greffe rénale. De futures études sur des cohortes internationales sont importantes pour soutenir la validité externe de nos résultats
Changer pour durer, ou le travail en tension. Influence des ressources sur deux trajectoires d’agriculteurs
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A glycosylated lipooctapeptide promotes uptake and growth of Mycobacterium abscessus in the host
No full textInternational audiencePathogenic mycobacteria produce a wide array of lipids which participate in host cell interactions and virulence. While some of these are conserved across all mycobacteria, others, like glycopeptidolipids (GPL), are restricted to a few species. Mycobacterium abscessus , an emerging rapid-growing pathogen, transitions from a smooth to a virulent rough variant upon the loss of surface GPL. Here, we discovered that M. abscessus and phylogenetically-close species harbor a second GPL-related locus, comprising two adjacent non-ribosomal peptide synthetase genes, MAB_4690c and MAB_4691c . A MAB_4690c deletion mutant (Δ MAB_4690c ) failed to produce a yet undescribed lipid, designated GL8P for glycosylated lipooctapeptide, sharing an acylated octapeptide core adorned by mono or di- O -rhamnosyl substituents. Δ MAB_4690c exhibited impaired uptake and survival in THP-1 cells and was attenuated in mice. Importantly, GL8P elicited a strong humoral response in patients infected with M. abscessus . These results highlight the role of GL8P in the pathophysiology of infection by rough M . abscessus and suggest its potential as a selective marker for M . abscessus infections