The major averages closed mixed but well off their lows after spending much of Monday’s session in the red. The Dow Jones industrial average led with a 1% gain and the S&P 500 was up a fraction. The Nasdaq trimmed its loss to 0.1% but had been down nearly 1% early. Volume swelled across the board, according to preliminary data. Discount retailers, hospitals and HMOs were among the top gainers in the stock market today.