U.S. markets rose slightly to open the week as strong gains by tech stocks helped to offset plummeting airline stocks. The Dow Jones Industrial Average closed up 28.72 points, or 0.12 percent, the S&P 500 climbed 0.42 percent and the Nasdaq Composite rose 1.23 percent. Netflix stock climbed 3.10 percent, Microsoft stock rose 2.45 percent, the Facebook stock grew 1.48 percent and Amazon stock increased 1.31 percent. Investor Warren Buffett ...