Gold miner Centamin Egypt won back some of the losses it sustained during the turmoil in that country, helped by the higher gold price. Fellow gold group, Russia-focused Petropavlovsk also advanced.Investors had an appetite for sausage skins maker Devro, which produced full-fat results for 2010 with operating margin improving sharply to 16.1% from 12.4%. Profit before tax and exceptional items in 2010 rose 44.4% to £36.3m from £25.1m in 2009. However, bluetooth chip specialist CSR slumped after it unveiled a $680m merger with US peer Zoran accompanied by a $240m share buyback programme.Shares in grocery delivery group Ocado fell sharply amid fears that a new delivery service operated by its main customer, the supermarket Waitrose, could hit sales hard.FTSE 250 - RisersCentamin Egypt Ltd. (CEY) 129.30p +5.81%Devro (DVO) 243.70p +5.04%Booker Group (BOK) 58.30p +3.83%Petropavlovsk (POG) 1,070.00p +3.58%Hochschild Mining (HOC) 578.50p +2.66%Kenmare Resources (KMR) 39.00p +2.63%EnQuest (ENQ) 135.80p +2.57%Charter International (CHTR) 750.50p +2.25%Mondi (MNDI) 546.50p +2.15%Go-Ahead Group (GOG) 1,435.00p +1.92%FTSE 250 - FallersCSR (CSR) 392.00p -9.68%Ocado Group (OCDO) 239.20p -7.75%CPP Group (CPP) 290.00p -5.84%Exillon Energy (EXI) 395.00p -5.14%Heritage Oil (HOIL) 278.70p -5.14%Avis Europe (AVE) 210.00p -4.98%Premier Foods (PFD) 27.80p -3.97%Ferrexpo (FXPO) 425.00p -3.23%Schroder Asia Pacific Fund (SDP) 213.00p -2.96%Hansen Transmissions International NV (DI) (HSN) 49.15p -2.87%