Barr body. Definition. noun. The small, dark-staining mass of inactive X chromosome within the nucleus of non-dividing cell. Supplement. Barr bodies are previously used as the basis for sex determination especially during the Olympics (see Barr test). Word origin: named after its discoverer Murray Llewellyn Barr, a Canadian anatomist who first identified the particle in the nucleus of neurons of female cats. Synonym: sex chromatin.
As of September 2011, there are nine Unified Combatant Commands as specified in Title 10 and the latest annual UCP. Six have regional responsibilities, and three have functional responsibilities.
Although not part of the original plan, the Joint Chiefs of Staff also created specified commands that had broad and continuing missions but were composed of forces from only one service. Examples include the U.S. Naval Forces, Eastern Atlantic and Mediterranean and the U.S. Air Force's Strategic Air Command.