HARARE (AFP) - Zimbabwe has introduced a new half-a-billion dollar bank note in a bid to tackle cash shortages fed by rampant inflation, the central bank said on Thursday. "Introducing the new 500,000,000 bearer cheque for your convenience," read a Reserve Bank of Zimbabwe full-page advert in the state daily, The Herald, displaying specimens of the new note. The note, comes into circulation 10 days after the introduction of a quarter-of-a-billion one early this month. This is the fourth set of high denomination notes to be issued this year, the first being in January when a 10 million dollar note...