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.
Each time the Unified Command Plan is updated, the organization of the combatant commands is reviewed for military efficiency and effectiveness, as well as alignment with national policy. Each unified command is led by a Combatant Commander (CCDR), who is a four-star general or admiral. CCDRs exercise combatant command (COCOM), a specific type of nontransferable command authority over assigned forces, regardless of branch of service, that is vested only in the CCDRs by federal law in 10 U.S.C. Â§ 164.