The Department was established in 1947 and is currently divided into three major Departmentsâthe Department of the Army, Navy and Air Forceâand has a military staff of 1,418,542 (553,044 US Army; 329,304 US Navy; 202,786 US Marine Corps; 333,408 US Air Force). The DoD is headed by the Secretary of Defense.
PREEMPTIVE analgesia is an antinociceptive treatment that prevents establishment of altered processing of afferent input, which amplifies postoperative pain. The concept of preemptive analgesia was formulated by Crile at the beginning of the previous century on the basis of clinical observations.
Preemptive multitasking is task in which a computer operating system uses some criteria to decide how long to allocate to any one task before giving another task a turn to use the operating system. The act of taking control of the operating system from one task and giving it to another task is called preempting.