The Federal Reserve, acting in coordination with other global central banking authorities, announces that it is slashing its key interest rate by a half-point to 1.50 percent. The move continues a string of aggressive actions led by Ben Bernanke and his central bank colleagues to cope with the worst financial crisis since the 1929 stock market crash. On Tuesday, the Fed said that it would buy massive amounts of "commercial paper" -- a short-term financing mechanism that many firms rely on to finance day-to-day operations.