Source: CBS News New York – Stocks are plunging in another broad sell-off as investors grow concerned about an economic slowdown in the U.S. and Europe. The Dow Jones industrial average was down more than nearly 350 points, erasing all of its gains this year. The index is now down more than 1,000 points from July 21. The Standard & Poor's 500 index sank more than 3 percent, bringing it more than 10 percent below its recent high of 1,363 [...]