94 research outputs found

    Chaotic Free-Space Laser Communication over Turbulent Channel

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    The dynamics of errors caused by atmospheric turbulence in a self-synchronizing chaos based communication system that stably transmits information over a ∼\sim5 km free-space laser link is studied experimentally. Binary information is transmitted using a chaotic sequence of short-term pulses as carrier. The information signal slightly shifts the chaotic time position of each pulse depending on the information bit. We report the results of an experimental analysis of the atmospheric turbulence in the channel and the impact of turbulence on the Bit-Error-Rate (BER) performance of this chaos based communication system.Comment: 4 pages, 5 figure

    Observer of the human cardiac sympathetic nerve activity using non-causal blind source separation

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    Nous présentons une méthode pour la reconstruction aveugle de deux variables de contrôle du système cardiovasculaire en utilisant seulement le rythme cardiaque et la tension artérielle. Le modèle de reconstruction est basé sur la séparation aveugle de source dans des mélanges convolutifs. L'algorithme d'apprentissage associé est déduit d'une approche de maximisation d'information. L'efficacité de la méthode a été verifiée en utilisant l'activité musculaire sympathique comme indicateur de l'activité cardiaque sympathique. Des résultats très satisfaisants et prometteurs ont été obtenus sur les signaux de cinq sujets

    Relationship Between Anti-DFS70 Autoantibodies and Oxidative Stress

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    Background: The anti-DFS70 autoantibodies are one of the most commonly and widely described agent of unknown clinical significance, frequently detected in healthy individuals. It is not known whether the DFS70 autoantibodies are protective or pathogenic. One of the factors suspected of inducing the formation of anti-DFS70 antibodies is increased oxidative stress. We evaluated the coexistence of anti-DFS70 antibodies with selected markers of oxidative stress and investigated whether these antibodies could be considered as indirect markers of oxidative stress. Methods: The intensity of oxidative stress was measured in all samples via indices of free-radical damage to lipids and proteins such as total oxidant status (TOS), concentrations of lipid hydroperoxides (LPH), lipofuscin (LPS), and malondialdehyde (MDA). The parameters of the non-enzymatic antioxidant system, such as total antioxidant status (TAS) and uric acid concentration (UA), were also measured, as well as the activity of superoxide dismutase (SOD). Based on TOS and TAS values, the oxidative stress index (OSI) was calculated. All samples were also tested with indirect immunofluorescence assay (IFA) and 357 samples were selected for direct monospecific anti DFS70 enzyme-linked immunosorbent assay (ELISA) testing. Results: The anti-DFS70 antibodies were confirmed by ELISA test in 21.29% of samples. Compared with anti-DFS70 negative samples we observed 23% lower concentration of LPH (P =.038) and 11% lower concentration of UA (P =.005). TOS was 20% lower (P =.014). The activity of SOD was up to 5% higher (P =.037). The Pearson correlation showed weak negative correlation for LPH, UA, and TOS and a weak positive correlation for SOD activity. Conclusion: In samples positive for the anti-DFS70 antibody a decreased level of oxidative stress was observed, especially in the case of samples with a high antibody titer. Anti-DFS70 antibodies can be considered as an indirect marker of reduced oxidative stress or a marker indicating the recent intensification of antioxidant processes

    A neuronal based baroreceptor model

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    Pattern formation in locally light coupled electrooptic interferometers

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    Chaotic synchronization and modulation of non-linear time-delayed feedback optical systems

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