A salient feature of the normal sinus node activity is its prominent beat-to-beat variability, which shows self-similarity on different time scales (fractal dynamics). However, in patients with sinus node dysfunction, short-term time sinus cycles show exaggerated variability, the characteristics of which have not been analyzed. Therefore, Poincaré plots and power spectral analysis were applied ...

The undirected power graph of a finite group $G$, $P(G)$, is a graph with the group elements of $G$ as vertices and two vertices are adjacent if and only if one of them is a power of the other. Let $A$ be an adjacency matrix of $P(G)$. An eigenvalue $lambda$ of $A$ is a main eigenvalue if the eigenspace $epsilon(lambda)$ has an eigenvector $X$ such that $X^{t}jjneq 0$, where $jj$ is the all-one...

Introduction: Recognizing what is happening in an environment has many potential applications, ranging from automatic surveillance systems to supporting users in ubiquitous environments. A key step to this end is to discover the kinds of similar activities that frequently occur in a particular domain. Equally important is the question of finding efficient characterizations for these different k...

Abstract A zero-dimensional (volume-averaged) and a pseudo-one-dimensional plug-flow (spatially resolved) model are developed to investigate atmospheric-pressure plasma jets operated with He, He/O 2 , He/N /O mixtures. The models coupled the Boltzmann equation under two-term approximation self-consistently calculate electron energy distribution function. An agreement is obtained between calcula...

The present paper reports for the first time the integration of a microfluidic system, electronics modules, amperometric sensor and display, all powered by a single micro direct methanol fuel cell. In addition to activating the electronic circuitry, the integrated power source also acts as a tuneable micropump. The electronics fulfil several functions. First, they regulate the micro fuel cell o...