Updated from 4:31 p.m. EDTStocks in New York lost ground for a second session Tuesday as investors braced for the start of earnings season. The Dow Jones Industrial Average lost 186.29 points, or 2.3% to 7789.56, and the S&P 500 was down 19.93 points, or 2.4%, at 815.55. The Nasdaq shed 45.10 points, or 2.8%, to 1561.61. On the Dow , Caterpillar ( CAT) declined 5.9%, and General Electric ( GE) was off by 4.8%. General Motors ( GM) fared the worst, tumbling 11.9% to $2.