Infecção por VIH entre imigrantes na Guiana Francesa: alto risco durante os primeiros anos após a chegada

Introduction. Over 75% of HIV patients in French Guiana are foreigners most of whom are actually infected locally. Objectives. We aimed to estimate the distribution of infections in time after arrival using a retrospective cohort. Methods. CD4 erosion modelling allowed to estimate the date of infection which was compared to the date of arrival in French Guiana in the subset of foreign patients that were estimated to have acquired HIV locally. Results. Among patients estimated to have been infected in French Guiana and having arrived after 1999, over half had been infected within 4 years and that a quarter of patients had acquired HIV within the 2 first years after arrival (median 3.9 years IQR=2.1-7.8 years). Conclusions. The added value of the present results is to show the rapid infection dynamics after arrival and emphasize the necessity of increasingly proactive combined prevention in recently arrived immigrants.Introdução. Mais de 75% dos pacientes com HIV na Guiana Francesa são estrangeiros, a maioria dos quais estão realmente infectados localmente. Objetivos. O nosso objetivo era estimar a distribuição das infecções no tempo após a chegada, utilizando uma coorte retrospectiva. Métodos. A modelagem da erosão CD4 permitiu estimar a data da infecção que foi comparada à data de chegada na Guiana Francesa no subconjunto de pacientes estrangeiros que foram estimados como tendo adquirido o HIV localmente.Resultados. Entre os pacientes estimados como tendo sido infectados na Guiana Francesa e tendo chegado após 1999, mais da metade tinha sido infectada dentro de 4 anos e que um quarto dos pacientes tinha adquirido o HIV dentro dos 2 primeiros anos após a chegada (mediana de 3,9 anos IQR=2,1-7,8 anos). Conclusões. O valor agregado dos resultados atuais é mostrar a rápida dinâmica da infecção após a chegada e enfatizar a necessidade de uma prevenção combinada cada vez mais proativa nos imigrantes recém-chegados

Observation Impact over the Antarctic During the Concordiasi Field Campaign

The impact of observations on analysis uncertainty and forecast performance was investigated for Austral Spring 2010 over the Southern polar area for four different systems (NRL, GMAO, ECMWF and Meteo-France), at the time of the Concordiasi field experiment. The largest multi model variance in 500 hPa height analyses is found in the southern sub-Antarctic oceanic region, where there are strong atmospheric dynamics, rapid forecast error growth, and fewer upper air wind observation data to constrain the analyses. In terms of data impact the most important observation components are shown to be AMSU, IASI, AIRS, GPS-RO, radiosonde, surface and atmospheric motion vector observations. For sounding data, radiosondes and dropsondes, one can note a large impact of temperature at low levels and a large impact of wind at high levels. Observing system experiments using the Concordiasi dropsondes show a large impact of the observations over the Antarctic plateau extending to lower latitudes with the forecast range, with a large impact around 50 to 70deg South. These experiments indicate there is a potential benefit of better using radiance data over land and sea-ice and innovative atmospheric motion vectors obtained from a combination of various satellites to fill the current data gaps and improve NWP in this region

Long-term neurological outcome of a cohort of 80 patients with classical organic acidurias.

International audienceBACKGROUND: Classical organic acidurias including methylmalonic aciduria (MMA), propionic aciduria (PA) and isovaleric aciduria (IVA) are severe inborn errors of the catabolism of branched-chain amino acids and odd-numbered chain fatty acids, presenting with severe complications. METHODS: This study investigated the long-term outcome of 80 patients with classical organic aciduria (38 with MMA, 24 with PA and 18 with IVA) by integrating clinical, radiological, biochemical and genetic data. RESULTS: Patients were followed-up for a mean of 14 years [age 3.3-46.3 years]. PA included a greater number of patients with abnormal neurological examination (37% in PA, 24% in MMA and 0% in IVA), lower psychometric scores (abnormal evaluation at age 3 years in 61% of patients with PA versus 26% in MMA and 18% in IVA) and more frequent basal ganglia lesions (56% of patients versus 36% in MMA and 17% in IVA). All patients with IVA presented a normal neurological examination and only 1/3 presented cognitive troubles. Prognosis for MMA was intermediate. Biochemical metabolite analysis excluding acute decompensations revealed significant progressive increases of glycine, alanine and glutamine particularly in PA and possibly in MMA but no correlation with neurological outcome. A significant increase of plasma methylmalonic acid was found in MMA patients with intellectual deficiency (mean level of 199 mumol/L versus 70 mumol/L, p < 0.05), with an estimated significant probability of severe outcome for average levels between birth and age 6 years above 167 mumol/L. Urinary 3-hydroxypropionate (3-HP) levels were significantly higher in PA patients with intellectual deficiency (mean level of 68.9 mumol/mmol of creatinine versus 34.6 mumol/mmol of creatinine, p < 0.01), with an estimated significant probability of severe outcome for average levels between birth and age 6 years above 55 mumol/mmol. As for molecular analysis, prognosis of MMA patients with mutations involving the MMAA gene was better compared to patients with mutations involving the MUT gene. CONCLUSION: Propionic aciduria had the most severe neurological prognosis. Our radiological and biochemical data are consistent with a mitochondrial toxicity mechanism. Follow-up plasma MMA and urinary 3-HP levels may have prognostic significance calling for greater efforts to optimize long-term management in these patients

Satellite and in situ observations for advancing global Earth surface modelling: a review

In this paper, we review the use of satellite-based remote sensing in combination with in situ data to inform Earth surface modelling. This involves verification and optimization methods that can handle both random and systematic errors and result in effective model improvement for both surface monitoring and prediction applications. The reasons for diverse remote sensing data and products include (i) their complementary areal and temporal coverage, (ii) their diverse and covariant information content, and (iii) their ability to complement in situ observations, which are often sparse and only locally representative. To improve our understanding of the complex behavior of the Earth system at the surface and sub-surface, we need large volumes of data from high-resolution modelling and remote sensing, since the Earth surface exhibits a high degree of heterogeneity and discontinuities in space and time. The spatial and temporal variability of the biosphere, hydrosphere, cryosphere and anthroposphere calls for an increased use of Earth observation (EO) data attaining volumes previously considered prohibitive. We review data availability and discuss recent examples where satellite remote sensing is used to infer observable surface quantities directly or indirectly, with particular emphasis on key parameters necessary for weather and climate prediction. Coordinated high-resolution remote-sensing and modelling/assimilation capabilities for the Earth surface are required to support an international application-focused effort

Influence de la résolution d'observations sur l'assimilation de données

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Assimilation variationnelle des observations de sondeurs infrarouges hyperspectraux (correction de biais et la détection nuageuse)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Vers une assimilation variationnelle des radiances satellitaires nuageuses

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Le sondage satellitaire et son évolution

De nos jours, le sondage par satellite est couramment utilisé par la météorologie opérationnelle et pour l'étude de l'atmosphère et du climat, grâce aux progrès réalisés depuis une vingtaineNowadays, satellite sounding is currently used for operational meteorology and for studies of the atmosphere and climate thanks to the methods for data inversion and assimilation that have been developed over the last twenty years. Instrumental techniques are also quickly evolving and will soon allow much improved sounders, like the IASI interferometer. We are waiting for sounders to be put aboard geostationary satellites and for active sounders in the next decade

Assimilation de données d'images télédétectées en météorologie

L évolution libre des fluides géostrophiques turbulents bidimensionnels fait apparaitre des tourbillons présentant une grande cohérence spatio-temporelle. Les écoulements atmosphériques tridimensionnels présentent également ce genre de structures cohérentes, notamment dans les champs de tourbillon potentiel. Certains aspects de la cyclogenèse semblent gouvernés, ou très sensibles, à la position et à l intensité de ces anomalies. Les images des satellites géostationnaires permettent par ailleurs de visualiser les signatures de ces phénomènes, appelées intrusions sèches. Une première partie du travail adapte des outils de traitement d image à la détection et au suivi des intrusions sèches sur les images vapeur d eau. On utilise une approche basée sur des multi-seuillages et le suivi automatisé de structures (logiciel RDT). Le développement de caractéristiques supplémentaires s avère nécessaire afin de sélectionner les intrusions associées à des événements dynamiques importants. L une d entre elles utilise l information sur le courant-jet à partir de vents d altitude de l ébauche. Un deuxième volet s applique à dégager une méthodologie de correction des structures en tourbillon potentiel à partir de ces informations. L assimilation de données conventionnelle ne permet pas d initialiser spécifiquement les structures. Nous décrivons les méthodes alternatives et étudions les possibilités, et limitations, d une méthodologie basée sur l assimilation de pseudo-observations. Cela débouche en particulier sur une version renouvelée de la relation entre vapeur d eau et tourbillon potentiel. Les outils développés sont appliqués à la prévision de la tempête des Landes (2006). L utilisation de données de concentration d ozone est finalement évoquée comme une méthode alternative d initialisation du tourbillon potentiel à la tropopauseIsolated vortices have been shown to emerge in two-dimensional and geostrophic turbulent flows. Coherent structures are apparent in three-dimensional atmospheric flows as well, and may share the property to determine the non-linear evolution and the predictability of the flow. Potential vorticity anomalies have indeed been shown to be of primary importance for cyclogenesis of mid-latitude storms. Their signature can be detected in satellite water vapour images and are known as dry intrusions. The first part of this work proceeds the tracking of dry intrusions on images. We use image processing tools based on thresholding algorithm, and develop additional filters to select relevant cells. One of this filters uses dynamical information on the jet from the background upper-level wind. We highlight the fact that conventional data assimilation does not handle coherent structures, and describe alternative procedures. We focus then on the assimilation of bogussed potential vorticity observations. This leads to a new vision of the relationship between water vapour and potential vorticity. The case study of the storms that has affected the Landes region in 2006 is then presented. We finally pinpoint ozone data as an alternative way to improve the initialization of upper-level potential vorticityPARIS-EST-Université (770839901) / SudocSudocFranceF

Global 4DVAR Assimilation and Forecast Experiments Using AMSU Observations over Land. Part I: Impacts of Various Land Surface Emissivity Parameterizations

International audienceTo improve the assimilation of Advanced Microwave Sounding Unit-A and -B (AMSU-A and -B) observations over land, three methods, based either on an estimation of the land emissivity or the land skin temperature directly from satellite observations, have been developed. Some feasibility studies have been performed in the Me´te´o-France assimilation system in order to choose the most appropriate method for the system. This study reports on three 2-month assimilation and forecast experiments that use different methods to estimate AMSU-A and -B land emissivities together with the operational run as a control experiment. The experiments and the control have been subjected to several comparisons. The performance of the observation operator for simulating window channel brightness temperatures has been studied. The study shows considerable improvements in the statistics of the window channels' first-guess departures (bias, standard deviation). The correlations between the observations and the model's simulations have also been improved, especially over snow-covered areas. The performances of the assimilation system, in terms of cost function change, have been examined: the cost function is generally improved during the screening and remains stable during the minimization. Moreover, comparisons have been made in terms of impacts on both analyses and forecasts