ia al-khatib institute of community and public health, birzeit university, west bank, palestine institute of environmental and water studies, birzeit university, west bank, palestine w el ansari faculty of applied sciences, university of gloucestershire, oxstalls campus, oxstalls lane, gloucester gl2 9hw, uk ta areqat faculty of graduate studies, birzeit university, west bank, palestine ra darkhawaja faculty of graduate studies, birzeit university, west bank, palestine sh mansour faculty of graduate studies, birzeit university, west bank, palestine ma tucktuck faculty of graduate studies, birzeit university, west bank, palestine