Global attractivity for a logistic equation with piecewise constant argument

In this paper we give a best possible condition for global attractivity of a logistic equation with piecewise constant argument ¶¶\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $ y'(t)=r(t)y(t)\left\{1-\frac{y([t])}{K}\right\}, \quad t\geq 0 $\end{document}¶¶ where \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $ [\cdot] $\end{document} denotes the greatest integer function, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $ r:[0,\infty) \to [0,\infty) $\end{document} is a continuous function and K is a positive constant.