Stocks pared losses in the last hour of trade Tuesday to close off their session lows. The Dow Jones industrial average ended down 1.1%, the S&P 500 shed 1.2% and the Nasdaq fell 1.5%. Volume was mixed, running higher on the NYSE and lower on the Nasdaq, according to preliminary data. Losers trumped winners by nearly a 4-1 ratio on both exchanges, as few industry groups were spared in the sell-off.