en عمومى General پژوهشي Research paper <p>This paper is devoted to the study of an eigenvalue second order differential equation, supplied with homogenous Dirichlet conditions and set on the real line. In the linear case, the equation arises in the study of a reaction-diffusion system involved in disease propagation throughout a given population. Under some relations upon the real parameters and coefficients, we present some existence and nonexistence results. We use a variational method and fixed point arguments.</p> Linear and sub-linear ODEs, Variational Method, Fixed point Theorems, Compactness Criterion. 65 81 http://ijmsi.ir/browse.php?a_code=A-10-1-70&slc_lang=en&sid=1 Smail Djebali 10031947532846002119 10031947532846002119 Yes Otared Kavian 10031947532846002120 10031947532846002120 No Toufik Moussaoui 10031947532846002121 10031947532846002121 No