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Isolated singularities of solutions of a 2-D diffusion equation with mixed reaction
No full textInternational audienceWe study the local properties of positive solutions of the equation -∆u + ae bu = m |∇u| q in a punctured domain Ω \ {0} of R 2 where m, a, b are positive parameters and q > 1. We study particularly the existence of solutions with an isolated singularity and the local behaviour of such singular solutions.</div
On the origin and distribution of internal erosion signatures in the floodplain protected by river dikes
No full textThe subsoils of river dikes are often composed of highly permeable and low-density river sediments. Thus, erosion signatures (leaks, sand boils, sinkholes) can appear in the protected floodplain during floods, highlighting the development of hydromorphodynamic phenomena below the surface, which may harm the safety of the dike system. A multi-scale methodology is deployed to understand and analyze the influence of floodplain architecture in terms of geological formations on the appearance of local erosion signatures. Particular attention is paid to the morphology of paleovalleys and paleochannels, in order to image the subsurface in terms of substrate types and interfaces using geophysical methods. This information makes it possible to propose internal erosion scenarios. Application to a study area in South of France (the Agly dike system) leads to new results. The classical backward erosion piping scheme is not relevant to explain the observed sand boils, as they are mainly caused by suffusion-type internal erosion process. Suffusion and contact erosion appear to be the origin of sinkholes. The distribution of these signatures appears to be directly related to the shape and dimensions of the paleovalley and paleochannels, as well as to the presence of a low-permeability topsoil
Re-evaluation of the concept of basaloid follicular hamartoma associated with naevoid basal cell carcinoma syndrome: a morphological, immunohistochemical and molecular study
No full textInternational audienceNaevoid basal cell carcinoma syndrome (NBCCS) is a rare genodermatosis caused by germline mutations in genes of the Sonic Hedgehog (SHH) pathway and is characterised by early onset of multiple basal cell carcinomas (BCCs). Although skin tumours with follicular differentiation, notably basaloid follicular hamartoma (BFH), have been reported in NBCCS, their relations with BCC are poorly defined. In this context, the aim of this study was to clarify morphological, immunohistochemical and molecular features of BFH arising in a context of NBCCS. A total of 140 skin tumours from NBCCS and 140 control BCC tumours were reviewed, blinded to clinical data and classified as BCC or BFH. The morphological characteristics of these two groups were then compared. Twenty cases were submitted for immunohistochemical and molecular analysis. Thirty-three tumours among the exploratory cohort were classified as BFH and were exclusively detected in NBCCS patients. Histopathological criteria that were significantly different from BCC were as follows: a small size (<1.5 mm), connection to a hair follicle, arborescent organoid architecture, lack of cytological atypia and infundibulocystic differentiation. Immunohistochemical analysis confirmed activation of the SHH pathway in these lesions. Targeted next-generation sequencing suggested that MYCN and GLI2/3 amplifications and TP53 mutations might be involved in progression of these follicular tumours to BCC. Our study confirms the high prevalence of BFH, representing up to 24% of skin tumours in NBCCS and potentially being BCC precursors
It is not only whether I approach but also why I approach: A registered report on the role of action framing in approach/avoidance training effects
No full textInternational audienceResearch on approach/avoidance training (AAT) effects shows that approach (i.e., reducing the distance between the self and a stimulus) leads to more positive evaluations of stimuli than avoidance (i.e., increasing the distance between the self and a stimulus). The present experiments relied on a grounded cognition approach to extend this finding by investigating the framing-dependency of AAT effects on facial representations of target stimuli. In a Preliminary Experiment, using antagonistic types of approach (affiliative vs. aggressive) and a reverse correlation paradigm, we found that approach led to more positive facial representations than avoidance when approach was portrayed as affiliative, but this effect decreased and tended to reverse (i.e., yielding more negative facial representations) when approach was portrayed as aggressive. Two registered experiments extended these results while also addressing important limitations of the Preliminary Experiment. First, to prevent any contrast emerging from the joint use of approach and avoidance, Experiment 1 isolated the unique effects of affiliative approach, aggressive approach, and avoidance compared to a control action. We also explored whether aggressive approach and avoidance (two negatively valenced yet distinct actions) produced negative effects characterized by divergent outcomes on facial features (e.g., weak vs. dominant). Second, Experiment 2 tested the importance of the experiential component of approach/avoidance actions by comparing the AAT with a mere instructions condition. Results of Experiments 1 and 2 proved consistent with a framing-dependency of AAT effects. Unveiling the framing-dependency of AAT effects challenges some of the current theoretical views on AAT effects
Coopération en classe : une expérience à accompagner pour apprendre et construire une expérience démocratique constructive
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Transcender les frontières : une exploration sociale, urbaine et politique
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Cutaneous hybrid cysts with matrical differentiation are mostly sporadic and related to CTNNB1 mutation
No full textInternational audienceRecurrent mutations in the CTNNB1 or APC genes leading to the activation of the Wnt/betacatenin pathway are observed in adnexal tumors with matrical differentiation. While most pilomatricomas arise sporadically and harbor CTNNB1 mutations, cutaneous hybrid cysts combining epidermal and matrical differentiations have been mostly reported in a context of the familial adenomatosis polyposis/Gardner's syndrome related to germinal mutations of APC. The objective of this study is to understand the pathogenesis of hybrid cysts combining epidermal and matrical differentiations. The 287 cases diagnosed as pilomatricoma/hybrid cysts registered between January 1, 2015 and February 21, 2023 in the Pathology Department at Tours University Hospital Center were considered for inclusion. After diagnosis confirmation, all cases were classified as pilomatricomas or hybrid cysts. Clinical data and microscopic features of the two groups were compared. Immunohistochemical detection of the betacatenin and CTNNB1/APC genes sequencing were performed in all hybrid cysts. Among the cohort, ten cases were classified as hybrid cysts (4%). None had a personal or familial history of familial adenomatosis polyposis. The immunochemistry confirmed a betacatenin nuclear expression in the matrical component in all excepted one cases, while no nuclear accumulation was observed in the epidermal component of most hybrid cysts (n = 8, 80%). CTNNB1 mutations were detected in all hybrid cysts with interpretable sequencing data (n = 7/10). By contrast, only a variant of uncertain significance (class 3) was detected in APC in association with a pathogenic CTNNB1 mutation in one case. Hybrid cysts are rare entities consisting in 4% of the tumors analyzed in our study. Our results suggest that most hybrid cysts occur sporadically and are associated with CTNNB1 somatic mutations
Systematic Review and Meta-Analysis of Remineralizing Agents: Outcomes on White Spot Lesions
No full textInternational audienceDental caries is a widespread issue impacting global oral health. White spot lesions, the earliest stage of caries, compromise enamel's esthetics and integrity. Remineralization therapies, both fluoride and non-fluoride based, aim to restore enamel, but limited comparative data exist on their effects on lesion depth and microhardness. Thus, the aim of this systematic review was to evaluate the efficacy of remineralizing agents on lesion depth and microhardness of human teeth. The literature search included the following five databases: PubMed, Web of Science, Scielo, SCOPUS, and EMBASE from the period 2012 to October 2022. Studies evaluating lesion depth and microhardness in human teeth after the application of a remineralizing agent were considered for review. The meta-analysis was performed using RevMan 5.4 (The Cochrane Collaboration, Copenhagen, Denmark). A random effect model was used to pool estimate of effect and its 95% confidence intervals (CIs) for surface microhardness and depth lesion. Subgroup analyses were performed considering the presence of fluoride or not in the remineralization agent. Thirty-three studies were included in the qualitative review. Of these, twenty-six studies were included in the meta-analysis. The main risks of bias associated with the studies included a lack of blinding of the test operator and failure to obtain sample size. To conclude, fluorinated agents are more effective in remineralizing artificially induced white spot lesion than non-fluoride remineralizing agents.</div
L'age affecte-t-il la métacognition ? Une étude inter-domaines à l'aide d'un cadre hiérarchique Bayésien
No full textInternational audienceAccording to previous research, the accuracy of metacognitive judgments in aging depends on the cognitive domain involved in the task, the experimental design, and the metacognitive index used. Older adults are frequently less accurate than younger adults in judging their episodic memory, while no difference is typically observed for semantic metamemory. In addition, age-related changes in metaperception appear to be highly taskdependent. Other metacognitive domains (such as metacognition of executive functioning) have been seldom explored. This study aimed to integrate methodological and theoretical advances in the study of metacognition to answer the question of whether metacognition is impaired in healthy aging. Data were collected in a large sample (n = 443) of participants aged 18 to 79. Participants provided retrospective confidence judgments in four domains: episodic memory, semantic memory, executive functioning, and visual perception. Our measure of accuracy, metacognitive efficiency, was estimated using a hierarchical Bayesian implementation of the meta-d' model. Results showed that metacognitive efficiency decreased with age in the episodic task and increased with age in the semantic task. There was no effect of age on metacognitive efficiency in the executive and perception tasks. Moreover, metacognitive efficiency appeared to rely on a domain-general process in older adults. Explaining the episodic metamemory deficit in aging could help understand the difficulties of older adults to use inferential processes for memory search and retrieval as well as their difficulties to implement memory strategies.Selon des recherches antérieures, la précision des jugements métacognitifs dans le vieillissement dépend du domaine cognitif impliqué dans la tâche, de la conception expérimentale et de l'indice métacognitif utilisé. Les personnes âgées sont souvent moins précises que les jeunes adultes lorsqu'elles jugent leur mémoire épisodique, alors qu'aucune différence n'est généralement observée pour la métamémoire sémantique. En outre, les changements liés à l'âge dans la métaperception semblent dépendre fortement de la tâche. D'autres domaines métacognitifs (tels que la métacognition du fonctionnement exécutif) ont été rarement étudiés. Cette étude visait à intégrer les avancées méthodologiques et théoriques dans l'étude de la métacognition afin de comprendre si la métacognition est altérée au cours du vieillissement en bonne santé. Des données ont été recueillies auprès d'un large échantillon (n = 443) de participants âgés de 18 à 79 ans. Les participants ont fourni des jugements de confiance rétrospectifs dans quatre domaines : la mémoire épisodique, la mémoire sémantique, les fonctions exécutives et la perception visuelle. Notre mesure de la précision, l'efficience métacognitive, a été estimée à l'aide d'un modèle hiérarchique bayésien basé sur le méta-d'. Les résultats ont montré que l'efficacité métacognitive diminuait avec l'âge dans la tâche épisodique et augmentait avec l'âge dans la tâche sémantique. Il n'y avait pas d'effet de l'âge sur l'efficacité métacognitive dans les tâches exécutives et de perception visuelle. De plus, l'efficacité métacognitive semble s'appuyer sur un processus domaine général chez les adultes plus âgés. L'explication du déficit de métamémoire épisodique dans le vieillissement pourrait aider à comprendre les difficultés des adultes âgés à utiliser des processus inférentiels pour la recherche et la récupération en mémoire, ainsi que leurs difficultés à mettre en œuvre des stratégies de mémoire