Areas of the United States where the military conducts research, development, test and evaluation work need to be preserved, in the face of increasing civilian populations living near test areas and pressures to reduce overall testing costs, Defense Department officials said yesterday. Civilian populations are encroaching on military areas where RDT&E work is done and are impacting those operations, according to Gen. Lester Lyles, the head of Air Force Materiel Command. The United States is blessed with a "unique combination"...