F&O Outlook: Nifty discount narrows, OI upB G Shirsat / Mumbai April 10, 2008Strong buying in banking, engineering and power stocks lifted the markets in the last one hour, with the Sensex and Nifty registering modest gains.After trading at a discount through most of the day, the Nifty April futures moved to a premium in the last hour as bears covered short positions around 4700 levels.The Nifty April futures discount narrowed to five points on a closing basis, from the previous day