Global Attractivity of Positive Periodic Solutions for a Survival Model of Red Blood Cells

In this paper, we deal with a model for the survival of red blood cells with periodic coefficients (*)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \begin{array}{*{20}c} {{{x}\ifmmode{'}\else$'$\fi{\left( t \right)} = - \mu {\left( t \right)}x{\left( t \right)} + P{\left( t \right)}e^{{ - \gamma {\left( t \right)}x{\left( {t - r{\left( t \right)}} \right)}}} ,}} & {{t \geqslant 0.}} \\ \end{array} $$\end{document} A new sufficient condition for global attractivity of positive periodic solutions of Eq.(∗) is obtained. Our criterion improves corresponding result obtained by Li and Wang in 2005.