Difference in Res. Associate and Post Doc - (Mar/21/2009 )

Can some one explain me whats the difference in research associate and post doc......

Research Associate is a position title, and post-doc is a state. A post-doc (a situation one achieves after being granted a doctoral degree) might be a Research Associate, or might occupy another position, such as Instructor. Not all Research Associates are post-docs, and not all post-docs are Research Associates.