Stocks opened quietly higher Tuesday, with solar stocks and office supplies retailers leading the upside. The Dow Jones industrial average marched up 0.4%. The Nasdaq and the S&P 500 gained 0.3% each. Volume dipped a fraction on the Nasdaq and slumped 57% on the NYSE compared with the same time Friday. The stock market today starts a holiday-shortened week, with the S&P 500 struggling to maintain its seven-week win streak. The Nasdaq last week