3,423 research outputs found

    Oscillation and asymptotic behavior for a class of delay parabolic differential

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    AbstractSome comparative theorems are given for the oscillation and asymptotic behavior for a class of high order delay parabolic differential equations of the form ∂n(u(x,t)−p(t)u(x,t−τ))∂tn−a(t)△u+c(x,t,u)+∫abq(x,t,ξ)f(u(x,g1(t,ξ)),…,u(x,gl(t,ξ)))dσ(ξ)=0,(x,t)∈Ω×R+≡G, where n is an odd integer, Ω is a bounded domain in Rm with a smooth boundary ∂Ω, and △ is the Laplacian operation with three boundary value conditions. Our results extend some of those of [P. Wang, Oscillatory criteria of nonlinear hyperbolic equations with continuous deviating arguments, Appl. Math. Comput. 106 (1999), 163–169] substantially

    A Weight-Based Clustering Method

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    This paper proposes a weight-based self-constructing clustering method for time series data. Self-constructing clustering processes all the data points incrementally. If a data point is not similar enough to an existing cluster, then (1) if the point currently does not belong to any cluster, it forms a new cluster of its own; (2) otherwise, the point is removed from the cluster it currently belongs to before a new cluster is formed. However, if a data point is similar enough to an existing cluster, then (1) if the point currently does not belong to any cluster, it is added to the most similar cluster; (2) otherwise, it is removed from the cluster it currently belongs to and added to the most similar cluster. During the clustering process, weights are learned and considered in the calculations of similarity between data points and clusters. Experimental results show that our proposed approach performs more effectively than other methods for real world time series datasets

    A Modified Fast Approximated Power Iteration Subspace Tracking Method for Space-Time Adaptive Processing

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    We propose a subspace-tracking-based space-time adaptive processing technique for airborne radar applications. By applying a modified approximated power iteration subspace tracing algorithm, the principal subspace in which the clutter-plus-interference reside is estimated. Therefore, the moving targets are detected by projecting the data on the minor subspace which is orthogonal to the principal subspace. The proposed approach overcomes the shortcomings of the existing methods and has satisfactory performance. Simulation results confirm that the performance improvement is achieved at very small secondary sample support, a feature that is particularly attractive for applications in heterogeneous environments

    Idiopathic Ventricular Arrhythmias Originating From the Pulmonary Sinus Cusp Prevalence, Electrocardiographic/Electrophysiological Characteristics, and Catheter Ablation

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    AbstractBackgroundIdiopathic ventricular arrhythmias (VAs) originating from the pulmonary sinus cusp (PSC) have not been sufficiently clarified.ObjectivesThe goal of this study was to investigate the prevalence, electrocardiographic characteristics, mapping, and ablation of idiopathic VAs arising from the PSC.MethodsData were analyzed from 218 patients undergoing successful endocardial ablation of idiopathic VAs with a left bundle branch block morphology and inferior axis deviation.ResultsTwenty-four patients had VAs originating from the PSC. In the first 7 patients, initial ablation performed in the right ventricular outflow tract failed to abolish the clinical VAs but produced a small change in the QRS morphology in 3 patients. In all 24 patients, the earliest activation was eventually identified in the PSC, at which a sharp potential was observed preceding the QRS complex onset by 28.2 ± 2.9 ms. The successful ablation site was in the right cusp (RC) in 10 patients (42%), the left cusp (LC) in 8 (33%), and the anterior cusp (AC) in 6 (25%). Electrocardiographic analysis showed that RC-VAs had significantly larger R-wave amplitude in lead I and a smaller aVL/aVR ratio of Q-wave amplitude compared with AC-VAs and LC-VAs, respectively. The R-wave amplitude in inferior leads was smaller in VAs localized in the RC than in the LC but did not differ between VAs from the AC and LC.ConclusionsVAs arising from the PSC are not uncommon, and RC-VAs have unique electrocardiographic characteristics. These VAs can be successfully ablated within the PSC

    New Reassortant H5N6 Highly Pathogenic Avian Influenza Viruses in Southern China, 2014

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    New reassortant H5N6 highly pathogenic avian influenza viruses were isolated from apparently healthy domestic ducks in Southern China in 2014. Our results show that the viruses grew efficiently in eggs and replicated systemically in chickens. They were completely lethal in chicken (100% mortality), and the mean death time (MDT) was 6 to 7 days post-inoculation (DPI). The viruses could transmit in chickens by naïve contact. BLAST analysis revealed that their HA gene was most closely related to A/wild duck/Shangdong/628/2011 (H5N1), and their NA genes were most closely related to A/swine/Guangdong/K6/2010 (H6N6). The other genes had the highest identity with A/wild duck/Fujian/1/2011(H5N1). The results of phylogenetic analysis showed that their HA genes clustered into clade 2.3.4.4 of the H5N1 viruses and all genes derived from H5 were Mix-like or H6-like viruses. Thus, the new H5N6 viruses were reassortanted of H5N1 and H6N6 virus. Therefore, the circulation of the new H5N6 avian influenza viruses may become a threat to poultry and human health
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