After opening sharply lower, stocks staged an abrupt reversal, and for a time just before noon the Nasdaq was trading higher before softening. Oil, which was trading below $37 a barrel in the morning, its lowest level in seven years, also reversed and was trading up to 1% higher going into the noon hour. The Nasdaq was down 0.2%, the S&P 500 lost 0.6% and the Dow Jones industrial average tumbled 0.7% in the stock market today.