The Chinese currency Renminbi, or yuan,weakened against the U.S. dollar on Tuesday, with its central parity rate dropping 43 basis points to reach 6.1395 per U.S. dollar, according to the China Foreign Exchange Trading System. In China\'s foreign exchange spot market, the yuan is allowed to rise or fall by 1 percent from the central parity rate each trading day. The central parity rate of the yuan against the U.S. dollar is based on a weighted average of prices before the opening of the market each business day.