Un algorithme génétique interactif pour des problèmes de tournées de véhicules

National audienceNous proposons un algorithme génétique interactif pour la résolution de problèmes de tournées de véhicules. Dans le processus d’optimisation, les tâches sont clairement réparties entre l’humain et la machine : le système affiche graphiquement les solutions de la population courante, l’humain les inspecte visuellement et exprime des préférences de type « j’aime » ou « je n’aime pas » en spécifiant les parties qu’il juge intéressantes ou non intéressantes. Avant de générer une nouvelle population, ces annotations humaines sur les phénotypes sont traduites sur les génotypes pour pouvoir être prises en compte par l’algorithme génétique

Assistance informatique à l'interprétation des données en cartographie linguistique. Informatisation anthropocentrée du Nouvel Atlas Linguistique de la Basse-Bretagne

International audienceNous discutons les motivations et les caractéristiques fondamentales d'un projet de recherche qui vise à mettre sur pied un système informatique d'assistance à l'interprétation pour les besoins de la recherche en cartographie linguistique. Dans la première partie nous exposons rapidement les traits fondateurs de la démarche de la cartographie linguistique sur la trace d'un morceau de son histoire récente. Notre objectif est de montrer combien ses aspirations tissent, dès le début, avec le traitement des données, et, par voie de conséquence, combien elle est tributaire des moyens de ces traitements. Dans la seconde, nous discutons le thème de l'introduction de l'informatique à son secours. Cependant, nous cherchons à défendre parallèlement l'idée suivant laquelle l'appel à l'informatique peut être plus qu'un simple service de calcul, et qu'il peut être pensé comme facteur de jonction intersémiotique, entre les différents niveaux de données qui intéressent la cartographie linguistique. L'objectif de notre argument est coordonné par une vision interprétative de la discipline. Enfin, dans la troisième partie, nous montrons les premières réalisations informatiques issues d'une telle vision. Mots clés : Cartographie linguistique, systèmes anthropocentrés, traitement de données, assistance informatique à l'interprétation, atlas linguistique

Partage d'autorité dans un essaim de drones auto-organisé

National audienceThis paper addresses the human control of a large number of unmanned air vehicles (UAVs) for the surveillance of a sensitive outdoor area. We leverage the combination of sensor network and environment marking for swarm intelligence. This grants autonomy to the UAVs system and allows the operator to focus on noteworthy tasks like counter-intrusion. This paper presents the experimental results of the SMAART project

Étude numérique du comportement de l'équation de transfert radiatif des milieux semi-transparents Inversion de données spectroscopiques pour le CO_2

L'objectif de ce travail est l'inversion de mesures spectroscopiques afin de reconstituer les distributions de température et de concentration en gaz carbonique (CO_2) dans une flamme. Cette méthode non-intrusive de mesure est basée sur l'observation d'un spectre à très haute résolution et fortement sensible à la température. La résolution unidimensionnelle de l'équation du transfert radiatif a permis de simuler les spectres dans la zone étudiée. Les dérivées du modèle direct sont calculées efficacement par la technique de l'état adjoint ; elles permettent, d'une part, l'analyse de sensibilité du modèle, et d'autre part, le calcul d'une direction de descente pour l'optimisation. Une estimation a priori du nombre de paramètres identifia- bles relatif à un niveau de bruit donné a été réalisée à partir de la décomposition en valeurs singulières de la matrice jacobienne. Enfin, une méthode de type Gauss-Newton avec régions de confiance a été utilisée afin de retrouver les paramètres. La méthode est illustrée sur des exemples synthétiques puis validée dans un cas réel

Evolutionary Advantage Conferred by an Eukaryote-to-Eukaryote Gene Transfer Event in Wine Yeasts

Although an increasing number of horizontal gene transfers have been reported in eukaryotes, experimental evidence for their adaptive value is lacking. Here, we report the recent transfer of a 158-kb genomic region between Torulaspora microellipsoides and Saccharomyces cerevisiae wine yeasts or closely related strains. This genomic region has undergone several rearrangements in S. cerevisiae strains, including gene loss and gene conversion between two tandemly duplicated FOT genes encoding oligopeptide transporters. We show that FOT genes confer a strong competitive advantage during grape must fermentation by increasing the number and diversity of oligopeptides that yeast can utilize as a source of nitrogen, thereby improving biomass formation, fermentation efficiency, and cell viability. Thus, the acquisition of FOT genes has favored yeast adaptation to the nitrogen-limited wine fermentation environment. This finding indicates that anthropic environments offer substantial ecological opportunity for evolutionary diversification through gene exchange between distant yeast species

Respiratory pulse pressure variation fails to predict fluid responsiveness in acute respiratory distress syndrome

International audienceIntroduction: Fluid responsiveness prediction is of utmost interest during acute respiratory distress syndrome (ARDS), but the performance of respiratory pulse pressure variation (Δ RESP PP) has scarcely been reported. In patients with ARDS, the pathophysiology of Δ RESP PP may differ from that of healthy lungs because of low tidal volume (Vt), high respiratory rate, decreased lung and sometimes chest wall compliance, which increase alveolar and/or pleural pressure. We aimed to assess Δ RESP PP in a large ARDS population. Methods: Our study population of nonarrhythmic ARDS patients without inspiratory effort were considered responders if their cardiac output increased by >10% after 500-ml volume expansion. Results: Among the 65 included patients (26 responders), the area under the receiver-operating curve (AUC) for Δ RESP PP was 0.75 (95% confidence interval (CI 95): 0.62 to 0.85), and a best cutoff of 5% yielded positive and negative likelihood ratios of 4.8 (CI 95 : 3.6 to 6.2) and 0.32 (CI 95 : 0.1 to 0.8), respectively. Adjusting Δ RESP PP for Vt, airway driving pressure or respiratory variations in pulmonary artery occlusion pressure (ΔPAOP), a surrogate for pleural pressure variations, in 33 Swan-Ganz catheter carriers did not markedly improve its predictive performance. In patients with ΔPAOP above its median value (4 mmHg), AUC for Δ RESP PP was 1 (CI 95 : 0.73 to 1) as compared with 0.79 (CI 95 : 0.52 to 0.94) otherwise (P = 0.07). A 300-ml volume expansion induced a ≥2 mmHg increase of central venous pressure, suggesting a change in cardiac preload, in 40 patients, but none of the 28 of 40 nonresponders responded to an additional 200-ml volume expansion. Conclusions: During protective mechanical ventilation for early ARDS, partly because of insufficient changes in pleural pressure, Δ RESP PP performance was poor. Careful fluid challenges may be a safe alternative

A multicentre case-control study of nonsteroidal anti-inflammatory drugs as a risk factor for severe sepsis and septic shock

International audienceINTRODUCTION: We aimed to establish whether the use of nonsteroidal anti-inflammatory drugs (NSAIDs) during evolving bacterial community-acquired infection in adults is associated with severe sepsis or septic shock. METHODS: We conducted a multicentre case-control study in eight intensive care units. Cases were all adult patients admitted for severe sepsis or septic shock due to a bacterial community-acquired infection. Control individuals were patients hospitalized with a mild community-acquired infection. Each case was matched to one control for age, presence of diabetes and site of infection. RESULTS: The main outcome measures were the proportions of cases and controls exposed to NSAIDs or aspirin during the period of observation. In all, 152 matched pairs were analyzed. The use of NSAIDs or aspirin during the observation period did not differ between cases and controls (27% versus 28; odds ratio = 0.93, 95% confidence interval [CI] = 0.52 to 1.64). If aspirin was not considered or if a distinction was made between acute and chronic drug treatment, there remained no difference between groups. However, the median time to prescription of effective antibiotic therapy was longer for NSAID users (6 days, 95% CI = 3 to 7 days) than for nonusers (3 days, 95% CI = 2 to 3 days; P = 0.02). CONCLUSIONS: In this study, the use of NSAIDs or aspirin during evolving bacterial infection was frequent and occurred in one-quarter of the patients with such infection. Although the use of NSAIDs by patients with severe sepsis or septic shock did not differ from their use by those with mild infection at the same infected site, we observed a longer median time to prescription of effective antibiotic therapy in NSAID users

Defective Retroviral Endogenous RNA Is Efficiently Transmitted by Infectious Particles Produced on an Avian Retroviral Vector Packaging Cell Line

AbstractThis report describes the contamination of "helper-free" stocks of defective retroviral vector with particles bearing retroviral endogenous RNA. An avian leukosis virus-based packaging cell line was developed from LMH cells that bear the ev1, ev3, and ev6 retroviral endogenous loci. The results show that an endogenous retroviral transcript (ev3) was packaged into virions produced by this packaging cell line and was efficiently transferred along with the vector to target cells. The titer of the ev contaminant particles was estimated at 50 - 100 CA-p27gag-expressing units/ml of supernatant

Mountain torques and atmospheric oscillations

Theoretical work and general circulation model (GCM) experiments suggest that the midlatitude jet stream's interaction with large‐scale topography can drive intraseasonal oscillations in large‐scale atmospheric circulation patterns. In support of this theory, we present new observational evidence that mountain‐induced torques play a key role in 15–30‐day oscillations of the Northern Hemisphere circulation's dominant patterns. The affected patterns include the Arctic Oscillation (AO) and the Pacific‐North‐American (PNA) pattern. Positive torques both accelerate and anticipate the midlatitude westerly winds at these periodicities. Moreover, torque anomalies anticipate the onsets of weather regimes over the Pacific, as well as the break‐ups of hemispheric‐scale regimes

Prevalence of impairments, disabilities, handicaps and quality of life in the general population: a review of recent literature

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