Tokyo--Jan. 12--Finance Minister Kiichi Miyazawa denied that declines in Japanese stock prices could signal a forthcoming economic downturn and added, "Basically, I'm not worried," speaking after the Nikkei fell 1.7% Thursday to its lowest level since October 1998. Miyazawa also said that he isn't worried about the weakening of the yen, though it cleared the 118 mark against the U.S. dollar for a 17 1/2 month high overnight Thursday.