in this paper, we investigate some properties of eigenvalues and eigenfunctions of boundary value problems with separated boundary conditions. also, we obtain formal series solutions for some partial differential equations associated with the second order differential equation, and study necessary and sufficient conditions for the negative and positive eigenvalues of the boundary value problem....

regular participation in intensive physical exercise is associated with electro-morphological changes in the heart.   this benign process is called athlete’s heart. athlete’s heart resembles few pathologic conditions in some aspects. so differentiation of these conditions is very important which otherwise may lead to a catastrophic event such as sudden death. the most common causes of sudden de...