Confession Session: Learning from Others Mistakes

Accepted versio

Case Report - Kikuchi's disease associated with systemic lupus erythematosus

A 25-year-old multiparous female presented with fever, joint pains, facial rash and lymphadenopathy of three months′ duration. Lymph node biopsy revealed a diagnosis of Kikuchi′s disease. She fulfilled seven out of the 11 ARA criteria for SLE. The association of Kikuchi′s disease and SLE is rare

Caractérisation des sècheresses des sols en France et changement climatique : Résultats et applications du projet ClimSec

Le projet ClimSec a étudié l'impact du changement climatique sur la sécheresse et sur l'eau du sol en France en s'appuyant sur la réanalyse de la chaîne hydrométéorologique SAFRAN-ISBA-MODCOU (SIM) depuis 1958. Des indices standardisés, " Standardized Precipitation Index " (SPI) et " Standardized Soil Wetness Index " (SSWI), ont été utilisés pour caractériser les différents types de sécheresse (météorologique et agricole) à partir d'une climatologie de 50 ans. En 2011, ces indices ont été adaptés pour le suivi hydrologique opérationnel et pour répondre aux besoins de qualification de la sécheresse printanière exceptionnelle de cette année. Ces indices ont également été calculés en climat futur à partir des différentes projections climatiques régionalisées disponibles en métropole. Trois expériences particulières en matière de scénarios socio-économiques, de modèles climatiques et de méthodes de descente d'échelle ont permis d'apprécier l'importance relative des différentes sources d'incertitude dans l'évolution attendue des sécheresses. Ces données ont aussi permis de préciser les conditions de l'évolution temporelle des sécheresses, avec une aggravation plus rapide et plus intense des événements liés au déficit d'humidité du sol plutôt qu'au déficit de précipitation. Les projections climatiques indiquent surtout que notre pays risque de connaître, lors de la seconde moitié du XXIe siècle, des sécheresses quasi continues et de grande intensité, totalement inconnues dans le climat actuel. / The ClimSec project has studied the impact of climate change on drought and soil water over France by using a climatological reanalysis of the SAFRAN/ISBA/MODCOU suite (SIM) since 1958. Standardized drought indices for precipitation (SPI) and soil moisture (SSWI) have been defined for research purposes to characterize the various kinds of events. They were then adapted for operational hydrological monitoring and used to assess the exceptional drought of spring 2011. These indices were also calculated for future climate from the various regionalized climate projections available over France. Three particular experiments in socio-economic scenarios, climate models and downscaling methods have been run to estimate the relative importance of the different uncertainties in drought evolution. The assessment of 21st century drought evolution shows a much earlier and more intense occurrence of changes for agricultural droughts linked to soil moisture deficits than for meteorological drought linked with precipitation deficits. Climate projections suggest that France could be affected on the second half of the 21st century by a quasi-continuous drought with a strong intensity, totally unknown in present climate

Automated computer-aided diagnosis of splenic lesions due to abdominal trauma

Tulum, Gökalp (Arel Author), Osman, Onur (Arel Author)Background: Computer-aided detection in the setting of trauma presents unique challenges due to variations in shape and attenuation of the injured organs based on the timing and severity of the injury. We developed and validated an automated computer-aided diagnosis algorithm to detect splenic lesions such as laceration, contusion, subcapsular hematoma, perisplenic hematoma, and active extravasation using computed tomography (CT) images in patients sustaining blunt or penetrating abdominal trauma. Methods: We categorized the splenic pathologies into three groups: contusion/laceration, hematoma, and active extravasation. We first analyzed the spleen and perisplenic region by estimating the mean value and standard deviation of the spleen. We determined adaptive threshold values based on the histogram of the area and detected the lesions after morphological operations and volumetric comparisons. Results: The overall performance of the three computer-aided diagnosis (CAD) algorithms is an accuracy of 0.80, sensitivity of 0.95, specificity of 0.67, and a diagnostic odds ratio (DOR) of 40 with a 95 % confidence interval (CI): 14 to 117. The CAD of perisplenic hematoma had the highest diagnosis rates with an accuracy of 0.90, a sensitivity of 0.95, specificity of 0.80, and DOR of 76 with a 95 % CI: 13 to 442. Conclusions: We developed a new algorithm to detect post-traumatic splenic lesions automatically and with high accuracy. Our method could potentially lead to the automated diagnosis of all traumatic abdominal pathologies

Climate variability and trends in downscaled high-resolution simulations and projections over Metropolitan France

International audienceIn order to fulfill the society demand for climate information at the spatial scale allowing impact studies, long-term high-resolution climate simulations are produced, over an area covering metropolitan France. One of the major goals of this article is to investigate whether such simulations appropriately simulate the spatial and temporal variability of the current climate, using two simulation chains. These start from the global IPSL-CM4 climate model, using two regional models (LMDz and MM5) at moderate resolution (15-20 km), followed with a statistical downscaling method in order to reach a target resolution of 8 km. The statistical downscaling technique includes a non-parametric method that corrects the distribution by using high-resolution analyses over France. First the uncorrected simulations are evaluated against a set of high-resolution analyses, with a focus on temperature and precipitation. Uncorrected downscaled temperatures suffer from a cold bias that is present in the global model as well. Precipitations biases have a season- and model-dependent behavior. Dynamical models overestimate rainfall but with different patterns and amplitude, but both have underestimations in the South-Eastern area (Cevennes mountains) in winter. A variance decomposition shows that uncorrected simulations fairly well capture observed variances from inter-annual to high-frequency intra-seasonal time scales. After correction, distributions match with analyses by construction, but it is shown that spatial coherence, persistence properties of warm, cold and dry episodes also match to a certain extent. Another aim of the article is to describe the changes for future climate obtained using these simulations under Scenario A1B. Results are presented on the changes between current and mid-term future (2021-2050) averages and variability over France. Interestingly, even though the same global climate model is used at the boundaries, regional climate change responses from the two models significantly differ. © 2012 Springer-Verlag Berlin Heidelberg

Statistical issues about solar–climate relations

International audienceThe relationship between solar activity and temperature variation is a frequently discussed issue in climatology. This relationships is usually hypothesized on the basis of statistical analyses of temperature time series and time series related to solar activity. Recent studies (Le Mouël et al., 2008, 2009; Courtillot et al., 2010) focus on the variabilities of temperature and solar activity records to identify their relationships. We discuss the meaning of such analyses and propose a general framework to test the statistical significance for these variability-based analyses. This approach is illustrated using European temperature data sets and geomagnetic field variations. We show that tests for significant correlation between observed temperature variability and geomagnetic field variability is hindered by a low number of degrees of freedom introduced by excessively smoothing the variability-based statistics

Les connaissances scientifiques au service de la COP21 - Florilège de projets de recherche 2008-2015 du programme « Gestion et impacts du changement climatique », Novembre 2015

Dans le cadre de la tenue de la COP 21 à Paris le Commissariat Général au développement Durable "direction Recherche & Innovation" a publié un document intitulé : les connaissances scientifiques au service de la COP 21. Il s'agit d'un florilège de projets de recherche conduits sur la période 2008-2015 du programme "Gestion et impacts du changement climatique". L'objectif est de donner un éclairage grâce aux résultats de la recherche représentant un apport aux politiques publiques, de montrer ainsi les liens étroits qui existent entre connaissance et action, savoir et décision