T HE electrocardiographic pattern of short P-R interval and prolonged QRS with a normal P-S (Wolff-Parkinson-White syndrome, pre-excitation) has fascinated physicians since its description by Wolff, Parkinson, and White in 1930.1 Many theories have been advanced and numerous studies reported in an effort to explain this particular electrocardiographic pattern.2-4 Of the many concepts proposed, ...

Our goal is to develop a general formalization of abstract algebra suitable for a general reasoning. One of the most common ways to formalize abstract algebra is to make use of a module system to specify an algebra as a theory. However, this approach suffers from the fact that modules are usually not first-class objects in the formal system. In this paper, we develop a new approach based on the...

analyzing the nonlinear vibration of beams is one of the important issues in structural engineering. according to this, an impressive analytical method which is called modified iteration perturbation method (mipm) is used to obtain the behavior and frequency of a cantilever beam with geometric nonlinear. this new method is combined by the mickens and iteration methods. moreover, this method don...

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