It's time for the "up" to be put back in UPS.You've probably heard the investing adage, "Don't try to catch a falling knife." The premise is that buying a stock that's in a clear downtrend can backfire because you can't know whether it will decline even further.The old saying is often good advice, but not always. Sometimes, stocks that have fallen significantly and haven't rebounded are great picks.United Parcel Service (UPS 0.89%) appears to be a good example, in my opinion. This magnificent high-yield div ...