Impact of HFE genetic testing on clinical presentation of hereditary hemochromatosis: new epidemiological data

BACKGROUND: Hereditary hemochromatosis (HH) is a common inherited disorder of iron metabolism in Northern European populations. The discovery of a candidate gene in 1996 (HFE), and of its main mutation (C282Y), has radically altered the way to diagnose this disease. The aim of this study was to assess the impact of the HFE gene discovery on the clinical presentation and epidemiology of HH. METHODS: We studied our cohort of 415 patients homozygous for the C282Y allele and included in a phlebotomy program in a blood centre in western Brittany, France. RESULTS: In this cohort, 56.9% of the patients were male and 21.9% began their phlebotomy program before the implementation of the genetic test. A significant decrease in the sex ratio was noticed following implementation of this DNA test, from 3.79 to 1.03 (p < 10(-5)), meaning that the proportion of diagnosed females relatives to males greatly increased. The profile of HH patients at diagnosis changed after the DNA test became available. Serum ferritin and iron values were lower and there was a reduced frequency of clinical signs displayed at diagnosis, particularly skin pigmentation (20.1 vs. 40.4%, OR = 0.37, p < 0.001) and hepatomegaly (11.0 vs. 22.7%, OR = 0.42, p = 0.006). In contrast, fatigue became a more common symptom at diagnosis (68.0 vs. 51.2%, OR = 2.03, p = 0.004). CONCLUSION: This study highlights the importance of the HFE gene discovery, which has simplified the diagnosis of HH and modified its clinical presentation and epidemiology. This study precisely measures these changes. Enhanced diagnosis of HFE-related HH at an early stage and implementation of phlebotomy treatment are anticipated to maintain normal life expectancy for these patients

Technical guidance on monitoring for the Marine Stategy Framework Directive

The Marine Directors of the European Union (EU), Acceding Countries, Candidate Countries and EFTA Countries have jointly developed a common strategy for supporting the implementation of the Directive 2008/56/EC, “the Marine Strategy Framework Directive” (MSFD). The main aim of this strategy is to allow a coherent and harmonious implementation of the Directive. Focus is on methodological questions related to a common understanding of the technical and scientific implications of the Marine Strategy Framework Directive. In particular, one of the objectives of the strategy is the development of non-legally binding and practical documents, such as this technical guidance on monitoring for the MSFD. These documents are targeted to those experts who are directly or indirectly implementing the MSFD in the marine regions. The document has been prepared by the Joint Research Centre of the European Commission (JRC) with the contribution of experts from Member States, Regional Seas Conventions and ICES and following consultation of the Working Group on Good Environmental Status.JRC.H.1-Water Resource

Deux approches de l'inversion geoacoutisque (inversion par signaux large bande et approche variationnelle)

Les propriétés géoacoustiques du fond marin ont une influence majeure en acoustique sous-marine en particulier à très basses fréquences et par petits fonds. Pour les besoins du sonar, l'optimisation des prédictions de portée nécessite de disposer d'un modèle géoacoustique du fond qui rende compte des interactions du son avec le fond. Les méthodes proposées dans ce manuscrit visent à élaborer, par inversion de données acoustiques, des modèles du fond adaptés aux sonars en se calquant sur des configurations instrumentales proches des configurations d'utilisation de ceux-ci. Les modèles ainsi obtenus sont acoustiquement équivalents à la vérité terrain. La première approche exploite l'estimation de la réponse impulsionnelle du canal acoustique issue du filtrage adapté de signaux à large spectre fréquentiel émis par une source et reçus par un unique hydrophone. Elle permet d'une part d'affiner la connaissance des paramètres géométriques et d'autre part de calculer le coefficient de réflexion en onde plane du fond. Les limites de validité du modèle ainsi obtenu sont étudiées et la technique mise en oeuvre sur données acoustiques réelles. La seconde approche se fonde sur une approche variationnelle issue de la théorie du contrôle. Le champ de pression acoustique est dans ce cas "contrôlé" par la condition d'impédance au fond qui représente le modèle géoacoustique. La méthode repose sur la modélisation adjointe d'une approximation parabolique de l'équation de Helmholtz, qui permet de calculer de manière exacte le gradient des fonctions de coût définies dans l'algorithme. Les cas de conditions d'impédances locales et non locales sont étudiés. La mise en oeuvre de cette nouvelle méthode sur données simulées montre les fortes potentialités de cette approche.Seafloor geoacoustic properties are essential in underwater acoustics. This is particularly true for very low frequencies and shallow water environments. A geoacoustic model that is able to predict the sound propagation in an underwater environment is needed in order to optimize predictions of sonar performances. The methods for elaborating the geoacoustical models we present are based on the inversion of acoustical data. They aim to elaborate models adapted to sonars (through-the-sensor approach) by making use of instrumental configurations that are close to those of sonars. The geoacoustical models thus obtained are acoustically equivalent to ground truth models. The first approach exploits an estimation of the impulse response of the acoustical channel coming from the adapted filtering of broadband signals emitted by a source and received by a single hydrophone. This leads to a two-step method that first refine the knowledge of the geometrical parameters and then compute the seafloor plane wave reflection coefficient. The validity of the model thus obtained is examined and the technique applied to a real data set. The second approach is based on a variational approach coming from control theory. In this case, the acoustical pressure field is controlled by an impedance control function that is the geoacoustic model. The method is based on the formulation of the adjoint model of a parabolic approximation of Helmholtz's equation. The gradient of the cost functions defined in the algorithm is computed exactly. Local and non-local boundary conditions are examined. This method is potentially very promising.TOULON-BU Centrale (830622101) / SudocSudocFranceF

DENTS PROPRES ET NET

RENNES1-BU Santé (352382103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

An analytic multiple frequency adjoint-based inversion algorithm for parabolic-type approximations in ocean acoustics

info:eu-repo/semantics/publishe

Full-field tomography and Kalman tracking of the range-dependent sound speed field in a coastal water environment

The monitoring, assessment and prediction of dynamic processes in shallow water constitute an attractive challenge. The availability of targeted observations enable high-resolution ocean forecasting to develop the 4D environmental picture. In particular, range-resolving acoustic tomography data constitute an effective way to reduce the non-uniform distribution and sparsity of standard hydrographic observations. In this paper a Kalman filtering scheme is investigated for tracking the time variations of a range-dependent sound-speed field in a vertical slice of a shallow water environment from full-field acoustic data and a propagation model taking into account the acoustic properties of the seafloor and subseafloor. The basic measurement setup for each radial of a tomography system consists of a broadband, multifrequency sound source and a vertical receiver array spanning most of the water column. The state variables represent the main features of the sound-speed field in a low dimensional parameterization scheme using empirical orthogonal functions. To test the algorithm acoustic data are synthesized from ocean model predictions obtained in support of the MREA/BP07 experiment southeast of the island of Elba, Italy. Bottom geoacoustic parameters obtained from previous acoustic inversion experiments are input to a normal mode propagation model as a background dataset. Additional data such as sea-surface temperature data from satellite or in situ hydrographic observations provide a priori approximate information about the range dependency of the subsurface structure and an estimation of the sea-surface sound speed. The evolution of the entire sound-speed field in the vertical slice is then sequentially estimated by the inversion processor. The results show that the daily space and time variations of the simulated sound-speed field can be effectively tracked with an extended Kalman filter. The depth-integrated sound-speed error (RMS) remains lower than 0.3 m/s (0.09 °C) when the benchmark environment is completely determined in the parameter space and lower than 0.7 m/s (0.22 °C) for an approximate environment parameterization. © 2009 Elsevier B.V.Special issue on MREA and Coastal Processes: Challenges for Monitoring and PredictionSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Time-Frequency Processing of Signals Transmitted by Ships in a Multi-Path Environment

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