Japan's benchmark Nikkei 225 index has soared more than 10% a day after it set markets tumbling in Europe and on Wall Street, while other world markets appeared to have settled after the rollercoaster ride that started the week. The Japanese index fell back after its biggest early advance, gaining 8.7% by midmorning on Tuesday. On Monday, nearly everything on Wall Street tumbled as world markets quaked under fears the U.S. economy is slowing too much. The S&P 500 sank 3% Monday for its worst day in nearly two years. The Dow Jones Industrial Average dropped more than 1,000 points, and the Nasdaq composite slid 3.4%. That followed the Nikkei's 12.4% plunge, its worst since 1987.
