What arte tha main activities of a staff nurse?

This link explains it-
http://www.jobisjob.co.uk/healthcare/staff-nurse/job-description

A staff nurse has done special training and is above the rank of an ordinary nurse, but below the rank of sister or charge nurse.
Staff nurses give patients medications and injections and discuss patient care with the hospital doctors, and don't have to do ordinary nurses duties like making beds, delivering meals and drinks, emptying bedpans, or washing and bathing patients.