Assessing ocean-model sensitivity to wind forcing uncertainties

International audienceIn this paper, we assess the short-term forecast error of a mesoscale primitive-equation open-ocean model, induced by uncertainties in wind forcing. Statistics calculated from an ensemble of ocean states show that temperature forecast error is strongest at the top of the ensemble-mean thermocline, as a consequence of vertical displacement of the mixed-layer base around its ensemble mean. Horizontal pattern of the temperature error in the mixed-layer is mainly explained by horizontal advection and surface heat flux fluctuations. These two mechanisms and entrainment through the mixed-layer bottom are presented as the three processes responsible for thermal forecast error growth in the modeled upper ocean

Cumulative incidence of post‐infection asthma or wheezing among young children clinically diagnosed with respiratory syncytial virus infection in the United States: A retrospective database analysis

Background: Respiratory syncytial virus (RSV) infection is implicated in subsequent development of asthma/wheezing (AW) among term and pre-term infants. We describe the cumulative incidence of AW among hospitalized and ambulatory neonates/infants/toddlers following RSV infection diagnosis over three independent follow-up periods. Methods: Between January 1, 2007 and March 31, 2016, patients aged 0-2 years old with first clinical diagnosis of RSV infection were identified using the Optum® integrated electronic health records and claims database. Patients diagnosed with AW ≤30 days post-RSV diagnosis were excluded. Three cohorts with 1, 3 and 5 years of follow-up were stratified by presence or absence of specific RSV high-risk factors, including pre-term birth and pre-defined, pre-existing comorbidities. Descriptive statistics and logistic regression results were reported.Results: Overall, 9811, 4524 and 1788 RSV-infected high-risk-factor negative patients were included in 1, 3 and 5-year independent cohorts, respectively. Of these, 6.5%, 6.9% and 5.8%, respectively had RSV-related hospitalization. By the end of follow-up, 14.9%, 28.2% and 36.3% had AW events. Overall, 3030, 1378 and 552 RSV-infected high-risk-factor positive patients were included in the respective cohorts. Of these, 11.4%, 11.1% and 11.6%, respectively were hospitalized with initial RSV infection and 18.1%, 32.9% and 37.9% had subsequent AW events within the follow-up period. Logistic regression confirmed RSV-related hospitalization significantly increased the likelihood of developing AW (

A Real-World Analysis of Patient Characteristics and Predictors of Hospitalization Among US Medicare Beneficiaries with Respiratory Syncytial Virus Infection

Introduction: Little has been published on respiratory syncytial virus (RSV) among Medicare patients at high risk (HR) of RSV complications due to age or comorbidity. Methods: Adult patients (at least 18 years of age) with at least 1 diagnostic code for RSV were identified using the 5% US Medicare database from 2011 through 2015. Patients were required to have continuous health plan enrollment for 180 days pre- and 180 days post-RSV diagnosis (baseline and follow-up periods, respectively). HR was defined as diagnosis of chronic lung disease, congestive heart failure, or weakened immune system for 180 days during the base-line period. Patients were categorized as initially hospitalized if hospitalized within 1 day of RSV diagnosis. Logistic regression models were developed to determine predictors of initial hospitalization. Healthcare utilization and costs for 180 days pre- and post-RSV diagnosis were compared. Results: The study included 756 HR patients who were initially hospitalized with RSV diagnoses. Among these, 61.7% were diagnosed in the emergency department vs 15.3% in a physician’s office, with hypertension (76.3%), chronic obstructive pulmonary disease (COPD)(53.7%), and high cholesterol (52.0%) observed as the most prevalent comorbidities. Of these, COPD, congestive heart failure, chronic kidney disease, and previous evidence of pneumonia were significant predictors of hospitalization. Other significant predictors of hospitalization included older age, hematological malignancies, stroke, and baseline healthcare resource use. Among both HR and non-HR hospitalized patients, there was a significant increase in healthcare resource utilization following hospitalization, including the number of inpatient admissions and longer hospital stays post-RSV diagnosis. The total mean all-cause healthcare costs among HR hospitalized patients increased by $9210 per patient (p \ 0.0001) post-RSV diagnosis. Conclusion: Hospitalized Medicare beneficiaries with RSV infections pose a significant healthcare burden as compared with non-hospitalized patients, mainly driven by higher comorbidity, higher likelihood of multiple inpatient admissions, and costly medical interventions

Development and Qualification of Instrumented Unmanned Planes for Turbulence Observations in the Atmospheric Surface Layer

The development of new observation systems like drones, present an opportunity to measure differently the turbulence in the atmospheric boundary layer. One of the main advantage of the unmanned plane lies in its capacity to fly at very low heights which is not possible with piloted airplanes, and thus to in situ investigate the turbulence in a way complementary to instrumented towers/masts. In the recent years, we have developed in Toulouse (France) two platforms of different size. The first one, called OVLI-TA, is a small unmanned aerial system (UAS) (3kg, payload included). It is instrumented with a 5-hole probe on the nose of the airplane, a Pitot probe, a fast inertial measurement unit (IMU), a GPS receiver, as well as temperature and moisture sensors in specific housings. After wind tunnel calibrations, the drone’s flight tests were conducted in Lannemezan (France), where there is an equipped 60m tower, which constitutes a reference to our measurements. The drone then participated to the international project DACCIWA (Dynamics-Aerosol-Chemistry-Clouds Interactions In West Africa), in Benin. Moreover, another project is carried out about the instrumentation of a so-called “Boreal” drone, which weights 25 kg and can embark 5 kg of sensors and IMU with data fusion. The scientific payload relates to atmospheric turbulence, GNSS reflectometry and gravimetry. In addition, this UAS has a long endurance (up to 10 h) and is more robust to fly in turbulent conditions. We will present the instrumental packages of the two UASs, the results of qualification flights as well as the first scientific results obtained in the DACCIWA campaign. We will also give some examples of envisaged deployment and observation strategy in future campaigns

Variational assimilation of SSH variability from TOPEX/POSEIDON and ERSI into an eddy-permitting model of the North Atlantic

A first step for improving the climatological state of high‐resolution general circulation models by means of data assimilation is presented. A method developed for the assimilation of statistical characteristics into chaotic ocean models is applied to assimilate SSH variability from TOPEX/POSEIDON and ERS1 in association with temperature and salinity from the World Ocean Atlas 1997 in order to estimate the underlying mean circulation. The method requires a parameterization of SSH variability which derives from the approach of Green and Stone. By estimating initial conditions for temperature and salinity, a mean state is achieved which, although not fully consistent with the altimetric and climatological data, is markedly improved on time scales of one year in comparison to the control run. The assimilation of SSH variability data introduces complementary information about the main frontal structures consistent with climatological observations. The state is however not an equilibrium state and returns back to the first guess quasi‐equilibrium state for longer integration periods

Global patterns in monthly activity of influenza virus, respiratory syncytial virus, parainfluenza virus, and metapneumovirus: a systematic analysis

Background Influenza virus, respiratory syncytial virus, parainfluenza virus, and metapneumovirus are the most common viruses associated with acute lower respiratory infections in young children (= 65 years). A global report of the monthly activity of these viruses is needed to inform public health strategies and programmes for their control.Methods In this systematic analysis, we compiled data from a systematic literature review of studies published between Jan 1, 2000, and Dec 31, 2017; online datasets; and unpublished research data. Studies were eligible for inclusion if they reported laboratory-confirmed incidence data of human infection of influenza virus, respiratory syncytial virus, parainfluenza virus, or metapneumovirus, or a combination of these, for at least 12 consecutive months (or 52 weeks equivalent); stable testing practice throughout all years reported; virus results among residents in well-defined geographical locations; and aggregated virus results at least on a monthly basis. Data were extracted through a three-stage process, from which we calculated monthly annual average percentage (AAP) as the relative strength of virus activity. We defined duration of epidemics as the minimum number of months to account for 75% of annual positive samples, with each component month defined as an epidemic month. Furthermore, we modelled monthly AAP of influenza virus and respiratory syncytial virus using site-specific temperature and relative humidity for the prediction of local average epidemic months. We also predicted global epidemic months of influenza virus and respiratory syncytial virus on a 5 degrees by 5 degrees grid. The systematic review in this study is registered with PROSPERO, number CRD42018091628.Findings We initally identified 37 335 eligible studies. Of 21 065 studies remaining after exclusion of duplicates, 1081 full-text articles were assessed for eligibility, of which 185 were identified as eligible. We included 246 sites for influenza virus, 183 sites for respiratory syncytial virus, 83 sites for parainfluenza virus, and 65 sites for metapneumovirus. Influenza virus had clear seasonal epidemics in winter months in most temperate sites but timing of epidemics was more variable and less seasonal with decreasing distance from the equator. Unlike influenza virus, respiratory syncytial virus had clear seasonal epidemics in both temperate and tropical regions, starting in late summer months in the tropics of each hemisphere, reaching most temperate sites in winter months. In most temperate sites, influenza virus epidemics occurred later than respiratory syncytial virus (by 0.3 months [95% CI -0.3 to 0.9]) while no clear temporal order was observed in the tropics. Parainfluenza virus epidemics were found mostly in spring and early summer months in each hemisphere. Metapneumovirus epidemics occurred in late winter and spring in most temperate sites but the timing of epidemics was more diverse in the tropics. Influenza virus epidemics had shorter duration (3.8 months [3.6 to 4.0]) in temperate sites and longer duration (5.2 months [4.9 to 5.5]) in the tropics. Duration of epidemics was similar across all sites for respiratory syncytial virus (4.6 months [4.3 to 4.8]), as it was for metapneumovirus (4.8 months [4.4 to 5.1]). By comparison, parainfluenza virus had longer duration of epidemics (6.3 months [6.0 to 6.7]). Our model had good predictability in the average epidemic months of influenza virus in temperate regions and respiratory syncytial virus in both temperate and tropical regions. Through leave-one-out cross validation, the overall prediction error in the onset of epidemics was within 1 month (influenza virus -0.2 months [-0.6 to 0.1]; respiratory syncytial virus 0.1 months [-0.2 to 0.4]).Interpretation This study is the first to provide global representations of month-by-month activity of influenza virus, respiratory syncytial virus, parainfluenza virus, and metapneumovirus. Our model is helpful in predicting the local onset month of influenza virus and respiratory syncytial virus epidemics. The seasonality information has important implications for health services planning, the timing of respiratory syncytial virus passive prophylaxis, and the strategy of influenza virus and future respiratory syncytial virus vaccination. Copyright (C) 2019 The Author(s). Published by Elsevier Ltd

La morphologie des inclusions des aciers non refondus en relation avec la tolérance au dommage de ces aciers

Il est bien connu que les caractéristiques statiques et dynamiques des aciers sont influencées par leur état inclusionnaire.Les progrès réalisés ces dernières années en matière d’élaboration (affinage en poche chauffante, insufflation du désoxydant, etc...) ont permis d'améliorer considérablement la propreté du métal sans avoir à faire appel aux techniques de refusion.Cette maîtrise de l’état inclusionnaire (morphologie, nature et distribution des inclusions) permet d’améliorer certaines caractéristiques d’usage statiques et dynamiques de pièces aéronautiques

Le traitement thermo mécanique par matriçage facteur d’augmentation des performances des matériaux aéronautiques

Le traitement thermo-mécanique d’un matériau consiste à lui conférer des propriétés optimisées par un contrôle de la structure lors de la déformation à chaud. Pour le matriceur, ceci impose : de compléter les connaissances métallurgiques habituelles par la réponse du matériau à la déformation à chaud et de contrôler les déformations réalisées. Le deuxième impératif est particulièrement délicat dans le cas du matriçage puisque ce mode de transformation ne conduit pas à des déformations homogènes dans tout le volume du métal. Ceci nous a amenés à mettre en place des moyens de simulation permettant de déterminer les taux de déformation en chaque point (technique de visio-plasticité). L’acquisition de ces connaissances permet de réaliser des pièces aéronautiques avec des impositions particulièrement sévères, notamment des pièces moteur en super-alliage. Cela ouvre également des perspectives d’optimisation du matriçage à d’autres alliages tels que titane, acier, etc..

Résultats sur pièces vitales en aciers refondus sous laitier

Le procédé ESR a fait l'objet ces dernières années d'une extension relativement importante, répondant ainsi à la demande accrue de l'Aéronautique en métal de haute et très haute qualité.Un bilan métallurgique portant sur un nombre important de résultats est actuellement possible. En particulier, sont examinés dans cette communication des résultats obtenus sur des ensembles vitaux de l'Airbus :