There was a moment of hope earlier this week when U.S. officials rolled out details of their plan to rescue the banking system. But that has already given way to fears about a slowing global economy. Japan's leading stock index plunged more than 11 percent. That follows Wednesday's sharp tumble in U.S. stock prices. Japan's prime minister called the American bailout "insufficient." In other Asian stock markets, prices plummeted. And in Europe, stock prices began the day trading lower as well.