After ending last Friday's session in positive territory, the major U.S. stock indexes turned in a mixed performance during trading on Monday. While the Nasdaq and the S&P 500 saw further upside, the narrower Dow moved to the downside.The Dow fell by 226.19 points or 0.5 percent to 47,336.68, but the S&P 500 rose 11.77 points or 0.2 percent to 6,851.97 and the Nasdaq climbed 109.77 points or 0.5 percent to 23,834.72.The gain by the tech-heavy Nasdaq partly reflected a sharp increase by shares of Amazon (AM ...