Copyright © 2011 Çiğdem Karakaya, Bertan Badur and Can Aytekin. This is an open access article distributed
under the Creative Commons Attribution License unported 3.0, which permits unrestricted use, distribution,
and reproduction in any medium, provided that original work is properly cited. Contact author: Çiğdem
Karakaya e-maill: cigdem.karakaya@boun.edu.tr