The specific cause of Parkinsonâs is unknown; however, medical experts believe the symptoms are related to a chemical imbalance in the brain caused by brain-cell death. Parkinson's disease is chronic (persists over a long period of time), and progressive (symptoms grow worse over time).arkinson's disease (or, simply, Parkinson's or PD) is the most common form of parkinsonism, a group of motor system disorders.
Quick Answer. Non-mandatory ZIP codes were introduced to the United States in 1963. Robert Moon, a postal inspector with the United States Postal Service, proposed the ZIP code system as early as 1944. Continue Reading.
ZIP Code. 1  During World War II, thousands of experienced postal employees left to serve with the military. To offset the loss, in May 1943 the Post Office Department began a zoning address system in 124 of the largest cities. 2  Twenty years later, the Department implemented an even farther reaching plan, the Zoning Improvement Plan (ZIP) Code. The social correspondence of the 19th century had given way, gradually then explosively, to business mail. By 1963, 80 percent of all mail in the United States was business mail.