Strategies for processing images with 4D-Var data assimilation methods

Data Assimilation is a well-known mathematical technic used, in environmental sciences, to improve, thanks to observation data, the forecasts obtained by meteorological, oceanographic or air quality simulation models. It aims to solve the evolution equations, describing the dynamics of the state variables, and an observation equation, linking at each space-time location the state vector and the observations. Data Assimilation allows to get a better knowledge of the actual system's state, named the reference. In this article, we first describe various strategies that can be applied in the framework of variational data assimilation to study various image processing issues. Second, we detail the mathematical setting and the analysis of pros and cons of each strategy for the issue of motion estimation. Last, results are provided on synthetic images and satellite acquisitions.L'assimilation de données est un outil largement utilisé dans les sciences de l'environnement pour améliorer, au moyen de données d'observation, les prédictions obtenues par les modèles de simulation. Elle s'applique en météorologie, en océanographie et en qualité de l'air, par exemple. L'assimilation de données permet de résoudre les équations d'évolution, décrivant la dynamique des variables d'état du modèle, et les équations d'observation, qui lient le vecteur d'état et les observations. Dans cet article, nous décrivons plusieurs stratégies d'assimilation d'images, dans le contexte de la formulation faible de l'assimilation variationnelle. Nous détaillons ensuite les équations mathématiques de ces stratégies et nous analysons leurs avantages et défauts respectifs pour une application à l'estimation du mouvement. Des résultats sont fournis sur des données synthétiques et des images satellite

Validation of surface velocity estimated from satellite images

This report concerns the validation of surface velocity estimated from satellite images. The estimation is obtained with a dynamic model based on shallow-water equations. We first compare the stationary assumption to the shallow-water heuristics to justify our choice. Second, we quantify the quality of the estimation by measuring the misfit between the model output and the altimetry measures. Experiments are achieved on Sea Surface Temperature data acquired by the NOAA/AVHRR satellites over the Black Sea. The altimetry measures are obtained by two radar sensors: Envisat and GFO. The good adequacy between the shallow-water output and the altimetry data validates our motion estimation approach.Ce rapport de recherche concerne la validation de l'estimation de la vitesse de surface à partir d'images satellite. Cette estimation est effectuée avec un modèle de la dynamique, basé sur les équations shallow-water. Nous comparons d'abord l'hypothèse de stationnarité aux équations shallow-water afin de justifier notre choix. Puis, nous quantifions la qualité des estimations en mesurant l'écart entre la sortie du modèle et les mesures d'altimétrie. Les expérimentations sont effectuées en utilisant des données de température de surface, acquises au-dessus de la Mer Noire avec les satellites NOAA/AVHRR. Les mesures altimétriques proviennent de deux capteurs radar : Envisat et GFO. La bonne adéquation entre la sortie du modèle shallow-water et les données altimétriques valide notre approche d'estimation du mouvement

The development and validation of the LIMPRINT methodology

[Paper two of the LIMPRINT supplement. Lymphatic Research and Biology Supplement. June 2017

How do GP practices and patient characteristics influence the prescription of antidepressants? A cross-sectional study

BACKGROUND: Under-prescription of antidepressants (ADs) among people meeting the criteria for major depressive episodes and excessive prescription in less symptomatic patients have been reported. The reasons influencing general practitioners’ (GPs) prescription of ADs remain little explored. This study aimed at assessing the influence of GP and patient characteristics on AD prescription. METHODS: This cross-sectional study was based on a sample of 816 GPs working within the main health care insurance system in the Seine-Maritime district of France during 2010. Only GPs meeting the criteria for full-time GP practice were included. The ratio of AD prescription to overall prescription volume, a relative measure of AD prescription level, was calculated for each GP, using the defined daily dose (DDD) concept. Associations of this AD prescription ratio with GPs’ age, gender, practice location, number of years of practice, number of days of sickness certificates prescribed, number of home visits and consultations, number and mean age of registered patients, mean patient income, and number of patients with a chronic condition were assessed using univariate and multivariate analysis. RESULTS: The high prescribers were middle-aged (40–59) urban GPs, with a moderate number of consultations and fewer low-income and chronic patients. GPs’ workload (e.g., volume of prescribed drug reimbursement and number of consultations) had no influence on the AD prescription ratio. GPs with more patients with risk factors for depression prescribed fewer ADs, however, which could suggest the medications were under-prescribed among the at-risk population. CONCLUSIONS: Our study described a profile of the typical higher AD prescriber that did not include heavy workload. In future work, a more detailed assessment of all biopsychosocial components of the consultation and other influences on GP behavior such as prior training would be useful to explain AD prescription in GP’s practice. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12991-015-0041-7) contains supplementary material, which is available to authorized users

Clinical and translational implications of the caveolin gene family: lessons from mouse models and human genetic disorders.

Here we review the clinical and translational implications of the caveolin gene family for understanding the pathogenesis of human diseases, including breast and prostate cancers, pulmonary hypertension, cardiomyopathy, diabetes, and muscular dystrophy. Detailed phenotypic analysis of caveolin knockout mice has served to highlight the crucial role of a caveolin deficiency in the pathogenesis of many human disease processes. Mutations in the human caveolin genes are associated with a number of established genetic disorders (such as breast cancer, lipodystrophy, muscular dystrophy, and cardiomyopathy), making the caveolins important and novel targets for drug development. The implementation of new strategies for caveolin replacement therapy-including caveolin mimetic peptides-is ongoing

Les stratégies d'adaptation des filles victimes d'agression sexuelle : influences parentales et familiales

Les taux de prévalence et d'incidence des agressions sexuelles ainsi que leurs multiples conséquences justifient les nombreuses études portant sur cette problématique. Ainsi, plusieurs s'intéressent aux variables qui favorisent le meilleur ajustement possible des victimes. Parmi ces variables, les stratégies d'adaptation ressortent comme ayant un impact significatif. Le présent mémoire s ‘insère dans ce courant de recherche afin de mettre en lumière les mécanismes qui favorisent l'émergence de stratégies d'adaptation efficaces. Les variables liées au contexte familial et aux stratégies utilisées par les parents sont rapportées comme pouvant influencer les stratégies adoptées par les jeunes. Les stratégies d'adaptation de 90 victimes d'agression sexuelle, celles de leur parent ainsi que Sa qualité de l'environnement familial ont été analysées afin de déterminer dans quelle mesure les stratégies d'adaptation des filles victimes d'agression sexuelle sont en lien avec les stratégies d'adaptation de leurs parents. Les résultats indiquent que les stratégies utilisées par le parent ainsi que la qualité de l'environnement familial sont liées à l'utilisation de certaines stratégies dont la recherche de soutien social, la cote globale des stratégies d'approche, l'externalisation et l'évitement

Virtue in client centred care : a philosophical investigation of virtue and nursing in Canadian healthcare

Part of the mandate of the Canadian Nursing Association is to develop and maintain a 'code of ethics'. Provincial professional nursing associations have largely based their own ethical frameworks on this code. However, as Mitchell and Benner have argued, ethical codes fail to capture some essential elements of the ethical life of nurses. This signals a need for a more accurate and experience based ethical framework for nurses. One such attempt is a document published by the Registered Nurses Association of Ontario entitled 'Client Centred Care' that presents an ethical framework that relies on a nurses' practical wisdom and that emphasizes individual experiences of ethical situations based on close relationships with patients. Some traditional ethical frameworks in the philosophical field have come under attack by Neo-Aristotelian Virtue Ethicists for the same reasons. These philosophers, including Wiggins, Maclntyre, Hursthouse, Zagzebski, and MacDowell, have supplemented unsatisfactory, traditional ethical frameworks with one that emphasizes perception of salience, practical wisdom, and practice. Because they are similar in their approaches to ethical life, and in their criticisms of traditional ethical frameworks, 'Client Centred Care' lends itself well to the vocabulary and conceptual structure of Virtue Ethics. However, for all its merits, 'Client Centred Care' does not provide us with the rigor of a serious ethical text, leaving terms inadequately defined and many questions unanswered. This work is an effort to clarify the ethical claims of this text through the lens of Virtue Ethics. In doing so, I will expose some of the deficiencies of this ethical framework for nurses and propose a curative solution by examining the work of Narrative Ethicists such as Martha Nussbaum