Estimation of the survival probabilities by adjusting a Cox model to the tail

National audienceWithin the framework of a survival analysis model with censored life time data and an explanatory covariate, our goal is to predict the survival probability beyond the largest observed time. A Cox model with a constant underlying hazard function is proposed to adjust the tail of the life time distribution. Under some regularity conditions, we prove that the parameter estimators are convergent

Quel discours de « la » science l’hétérogénéité sémiotique des médias construit-elle ?

Le corpus discursif examiné ici est divers: articles de la presse écrite, caractérisés par la co-présence de textes iconiques et verbaux, émissions radiophoniques, où seul fonctionne le texte oral, émissions télévisées, où s’articulent images mobiles et messages linguistiques oraux, parfois accompagnés d’inserts écrits. Ce qui réunit ces fragments discursifs différents est double, puisque référentiel – ils parlent tous d’objets scientifiques en relation avec la vie quotidienne – et méthodologique: c’est leur hétérogénéité sémiotique, dans ce qu’elle présente de variations mais aussi de données communes, qui est étudiée. L’analyse permet de poser des hypothèses concernant le mode de construction du discours scientifique dans ces médias.What is “the” scientific discourse constructed by the media’s semiotic heterogeneity?The discursive data examined here is varied: newspaper articles, characterized by the co-presence of iconic and verbal texts; radio broadcasts, which are entirely based on oral texts; television programs, where mobile images and oral linguistic messages are combined, occasionally accompanied by written inserts. What reunites these different discursive fragments is dual, because it is referential –they all speak of scientific objects in relation to daily life  and methodological  it is their semiotic heterogeneity, which present variations but also similarities, which is studied. The analysis should allow the posing of hypotheses, to be verified on a larger amount of data, concerning the mode by which the scientific discourse in these medias is constructed

Quel discours de « la » science l’hétérogénéité sémiotique des médias construit-elle ?

Le corpus discursif examiné ici est divers: articles de la presse écrite, caractérisés par la co-présence de textes iconiques et verbaux, émissions radiophoniques, où seul fonctionne le texte oral, émissions télévisées, où s’articulent images mobiles et messages linguistiques oraux, parfois accompagnés d’inserts écrits. Ce qui réunit ces fragments discursifs différents est double, puisque référentiel – ils parlent tous d’objets scientifiques en relation avec la vie quotidienne – et méthodologique: c’est leur hétérogénéité sémiotique, dans ce qu’elle présente de variations mais aussi de données communes, qui est étudiée. L’analyse permet de poser des hypothèses concernant le mode de construction du discours scientifique dans ces médias.What is “the” scientific discourse constructed by the media’s semiotic heterogeneity?The discursive data examined here is varied: newspaper articles, characterized by the co-presence of iconic and verbal texts; radio broadcasts, which are entirely based on oral texts; television programs, where mobile images and oral linguistic messages are combined, occasionally accompanied by written inserts. What reunites these different discursive fragments is dual, because it is referential –they all speak of scientific objects in relation to daily life  and methodological  it is their semiotic heterogeneity, which present variations but also similarities, which is studied. The analysis should allow the posing of hypotheses, to be verified on a larger amount of data, concerning the mode by which the scientific discourse in these medias is constructed

Estimating Extracellular Fluid Volume in Healthy Individuals: Evaluation of Existing Formulae and Development of a New Equation

peer reviewedIntroduction: Several clinical settings require an accurate estimation of the physiologically expected extracellular fluid volume (ECFV). We aimed to analyze the performances of existing ECFV-estimating equations and to develop a new equation. Methods: The performances of 11 ECFV-estimating equations were analyzed in 228 healthy kidney donor candidates (Bichat Hospital, Paris, France) who underwent ECFV measurement using the distribution volume of 51Cr-labeled EDTA (51Cr-EDTA). An equation was developed using a penalized linear modeling approach (elastic net regression) and externally (Tenon Hospital, Paris, France, N = 142) validated. Results: Participants from Bichat (mean age 45.2 ± 12.0 years, 43.0% men) and Tenon (47.8 ± 10.3 years, 29.6% men) hospitals had a mean measured ECFV of 15.4 ± 2.8 l and 15.1 ± 2.1 l, respectively. Available ECFV-estimating formulae have highly variable precision and accuracy. The new equation incorporating body weight, height, sex, and age had better precision and accuracy than all other equations in the external validation cohort, with a median bias of −0.20 (95% CI: −0.35 to −0.05) l versus −2.63 (−2.87 to −2.42) l to −0.57 (− 0.83 to −0.40) l and 0.21 (0.12 to 0.43) l to 2.89 (2.65 to 3.11) l, for underestimating and overestimating equations, respectively, an interquartile range for the bias of 0.88 (0.70 to 1.08) l versus 0.91 (0.71 to 1.20) l to 1.93 (1.67 to 2.25) l, and an accuracy within 10% of 90.9% (83.8 to 94.4) versus 88.0% (81.0 to 92.3) to 8.5% (4.2 to 13.4). These results were consistent across subgroups defined by sex, body mass index (BMI), body surface area (BSA), age, and ethnicity. Conclusion: We developed and validated a new equation to estimate the individual reference value of ECFV, which is easily usable in clinical practice. Further validation in cohorts including individuals of extreme age and corpulence remains needed

Performance of creatinine-based equations to estimate glomerular filtration rate in White and Black populations in Europe, Brazil and Africa.

peer reviewed("[en] BACKGROUND: A new Chronic Kidney Disease Epidemiology Collaboration equation without the race variable has been recently proposed (CKD-EPIAS). This equation has neither been validated outside USA nor compared with the new European Kidney Function Consortium (EKFC) and Lund-Malmö Revised (LMREV) equations, developed in European cohorts. METHODS: Standardized creatinine and measured glomerular filtration rate (GFR) from the European EKFC cohorts (n = 13 856 including 6031 individuals in the external validation cohort), from France (n = 4429, including 964 Black Europeans), from Brazil (n = 100) and from Africa (n = 508) were used to test the performances of the equations. A matched analysis between White Europeans and Black Africans or Black Europeans was performed. RESULTS: In White Europeans (n = 9496), both the EKFC and LMREV equations outperformed CKD-EPIAS (bias of -0.6 and -3.2, respectively versus 5.0 mL/min/1.73 m², and accuracy within 30% of 86.9 and 87.4, respectively, versus 80.9%). In Black Europeans and Black Africans, the best performance was observed with the EKFC equation using a specific Q-value (= concentration of serum creatinine in healthy males and females). These results were confirmed in matched analyses, which showed that serum creatinine concentrations were different in White Europeans, Black Europeans and Black Africans for the same measured GFR, age, sex and body mass index. Creatinine differences were more relevant in males. CONCLUSION: In a European and African cohort, the performances of CKD-EPIAS remain suboptimal. The EKFC equation, using usual or dedicated population-specific Q-values, presents the best performance in the whole age range in the European and African populations included in this study.","[en] ",""

Hygiène du visage et formulation d'un démaquillant

LYON1-BU Santé (693882101) / SudocSudocFranceF

Hypo/hyperonymie et stratégies discursives

Mortureux Marie-Françoise, Petiot Geneviève. Hypo/hyperonymie et stratégies discursives. In: Langages, 25ᵉ année, n°98, 1990. L'hyponymie et l'hyperonymie, sous la direction de Marie-Françoise Mortureux. pp. 115-121

Compétences graphophonologique et phonographique chez des adultes en situation d'illettrisme (absence ou inefficience ?)

L'étude porte sur l'emploi du sous-principe phonographique par des individus en situation d'illettrisme les épreuves sont également administrées à un groupe contrôle. Elle montre que les modes de traitement graphophonologique (lecture) et phonographique (production écrite) existent quoique partiels et inefficients. L'illettrisme ne se résume pas à une unique source de dysfonctionnement. A l'échelle du groupe " illettrismes " étudié, chacune des opérations cognitives nécessaires au fonctionnement des modes de traitement graphophonologique et phonographique peut être défaillante. A l'échelle de l'individu, les dysfonctionnements peuvent se limiter à quelques opérations cognitives, parfois une seule ou les concerner toutes. Pour certains sujets, l'hypothèse d'une fossilisation dans des modes de traitement de type visuographique demeure. La capacité de manipulation métaphonémique des sujets est aussi mesurée. Apparaît un décalage entre l'analyse phonèmes/phonogrammes que les sujets réalisent lorsqu'ils écrivent des pseudo-mots et celle qu'ils ne parviennent pas à accomplir lorsque l'analyse porte sur les mots oraux. A l'issue de l'étude, nous proposons une réflexion autour de la modélisation du système d'identification de mots et de production écrite de mots des individus en situation d'illettrisme. Partant du modèle théorique à processeurs et reprenant le fait qu'il existe un fort décalage entre ce que les sujets de notre population réalisent en identification de mots par rapport à la production écrite, nous suggérons que le système d'identification de mots et de production écrite de mots fonctionne sur des connexions qui ne sont pas opérationnelles de façon réversible.LYON2/BRON-BU (690292101) / SudocSudocFranceF

Estimation of the extreme survival probabilities from censored data

International audienceThe Kaplan-Meier nonparametric estimator has become a standard tool for estimating a survival time distribution in a right censoring schema. However, if the censoring rate is high, this estimator does not provide a reliable estimation of the extreme survival probabilities. In this paper we propose to combine the nonparametric Kaplan-Meier estimator and a parametric-based model into one construction. The idea is to t the tail of the survival function with a parametric model while for the remaining to use the Kaplan-Meier estimator. A procedure for the automatic choice of the location of the tail based on a goodness-of- t test is proposed. This technique allows us to improve the estimation of the survival probabilities in the mid and long term. We perform numerical simulations which confirm the advantage of the proposed method