Stocks were mostly lower on Tuesday morning, led by declines in the Technology and Communication Services sectors. New data pointed to a continued slowdown in the housing market. The Case-Shiller National Home Price index fell 0.5% month-over-month in January. Year-over-year growth also slowed to 3.8% in January from 5.6% in December. On the earnings front, Walgreen shares rose nearly 4% after the company reported better-than-expected fiscal 2Q earnings, helped by strong phar