Relaxing the Gaussian assumption in Shrinkage and SURE in high dimension

Shrinkage estimation is a fundamental tool of modern statistics, pioneered by Charles Stein upon the discovery of his famous paradox. Despite a large subsequent literature, the efficiency of shrinkage, and the associated procedure known as Stein's Unbiased Risk Estimate, or SURE, has mainly been analysed in the Gaussian setting. Importing tools developed for use in the probabilistic area now known as Stein's method, the present work investigates the domain of validity of shrinkage and SURE away from the Gaussian. We show that shrinkage is efficient away from the Gaussian under very mild conditions on the distribution of the noise. SURE is also proved to be adaptive under similar assumptions, and in particular in a way that retains the classical asymptotics of Pinsker's theorem. Notably, shrinkage and SURE are shown to be efficient under mild distributional assumptions

Serum vitamin D levels of patients with oral squamous cell carcinoma (OSCC) and expression of vitamin D receptor in oral precancerous lesions and OSCC

Background: Resistance to programmed cell death (apoptosis) is a crucial factor for the carcinogenesis of oral squamous cell carcinoma (OSCC). Vitamin D (calcitriol) may overcome apoptosis resistance in tumor cells of OSCC. Vitamin D receptor (VDR) expression in oral precancerous lesions of OSCC has not been analyzed and serum vitamin D level seems to be a predictor of cancer development. Material and Methods: Expression of VDR was analyzed in normal oral mucosa (n=5), oral precursor lesions (simple hyperplasia, n=11; squamous intraepithelial neoplasia, SIN I-III, n=35), and OSCC specimen (n=42) by immunohistochemistry (IHC). Moreover, serum vitamin D levels were measured by 25(OH)D3 (calcidiol) in patients with OSCC (n=42) and correlated with IHC results. Results: Expression of VDR was significantly increased in precancerous and OSCC compared with normal tissue. Compared with SIN I-III lesions VDR expression significantly decreased in OSCC. Severe vitamin D deficiency was detected in our OSCC patient cohort but there was no significant correlation analyzed between serum vitamin D levels and corresponding immunohistochemically detected VDR expression in OSCC. Conclusions: Our survey provides the first evidence of VDR expression in precancerous lesions of OSCC. Apoptosis induction of VDR+ cells in oral precancerous lesions and OSCC by natural vitamin D or synthetic vitamin D compounds could be useful for chemoprevention. Moreover, systemically and/or locally applied, these compounds may act as sensitizers for apoptosis mediated by radio-, and chemotherapy treatment in OSCC

Computational strategies to combat COVID-19: useful tools to accelerate SARS-CoV-2 and coronavirus research

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is a novel virus of the family Coronaviridae. The virus causes the infectious disease COVID-19. The biology of coronaviruses has been studied for many years. However, bioinformatics tools designed explicitly for SARS-CoV-2 have only recently been developed as a rapid reaction to the need for fast detection, understanding and treatment of COVID-19. To control the ongoing COVID-19 pandemic, it is of utmost importance to get insight into the evolution and pathogenesis of the virus. In this review, we cover bioinformatics workflows and tools for the routine detection of SARS-CoV-2 infection, the reliable analysis of sequencing data, the tracking of the COVID-19 pandemic and evaluation of containment measures, the study of coronavirus evolution, the discovery of potential drug targets and development of therapeutic strategies. For each tool, we briefly describe its use case and how it advances research specifically for SARS-CoV-2. All tools are free to use and available online, either through web applications or public code repositories.Peer Reviewe

Quelques interrogations à propos de l' "objet" d'une analyse de discours de type statistique et de la réponse "Alceste"

REINERT Max - What can be the meaning of a statistical discourse analysis ? In this article, the creator of Alceste tries to show in what way his method is in the line of Jean-Paul Benzécri's Harris-type approach and in what way it departs from it. He first describes the propositional model that led Benzécri to envisage tables of a "Subjets x Predicates" sort. He then attempts to extend the notion of logical propositions, which reflect a state of things, to a more pragmatic unit of discourse (with a marked reference to the work of Charles Sanders Peirce). Finally, he presents the hypotheses which are at the basis of his own method of splitting up a corpus into "context units" ("unités de contexte").Dans cet article, le créateur d'Alceste essaie de montrer en quoi sa méthode se situe en continuité avec ce qu'il appelle l'approche Harissienne de Jean-Paul Benzécri et en quoi elle s'en démarque. Il évoque d'abord le modèle propositionnel qui a conduit Benzécri à s'intéresser à des tableaux de données du type "sujets x prédicats". Il tente ensuite d'élargir la notion de proposition logique, reflet d'un état de chose, à une unité de discours plus pragmatique (avec une référence marquée aux travaux de Charles Sanders Peirce) pour enfin présenter ses propres hypothèses à la base de sa méthode de découpage du corpus en "unités de contexte".Max Reinert. Quelques interrogations à propos de l' "objet" d'une analyse de discours de type statistique et de la réponse "Alceste". In: Langage et société, n°90, 1999. pp. 57-70

Une méthode de classification descendante hiérarchique : application à l'analyse lexicale par contexte

A. Reinert indiqué par erreur au niveau du titre sur l'article publiéInternational audienceVersion numérisée : http://www.numdam.org/item/CAD_1983__8_2_187_0