Shares in Dana Petroleum have steamed ahead after the oil & gas group Dana Petroleum announced a 'significant' gas find in the North Sea.A well at the Platypus prospect in the UK's part of the sea 'encountered some 218 vertical feet of good quality gas bearing sands.'Shares in Debenhams, which on Wednesday, posted a healthy rise in profits in the half year to 27 February as it shifted its emphasis to sales of higher margin own bought clothing from designer labels.Elsewhere in retail, bike and car parts specialist Halfords is lower but sportswear group Sports Direct moves ahead.FTSE 250 - RisersAshtead Group (AHT) 111.00p +8.82%International Personal Finance (IPF) 253.70p +3.72%Lamprell (LAM) 263.30p +3.25%SThree (STHR) 366.20p +3.01%BTG (BGC) 186.30p +2.93%Imagination Technologies (IMG) 259.00p +2.78%Dana Petroleum (DNX) 1,304.00p +2.76%Gartmore Group (GRT) 144.90p +2.48%Sports Direct International (SPD) 109.40p +2.43%Grainger (GRI) 142.00p +2.38%FTSE 250 - FallersPersimmon (PSN) 447.50p -2.29%Debenhams (DEB) 76.10p -2.25%EnQuest (ENQ) 101.80p -2.21%Halfords Group (HFD) 481.70p -1.93%Filtrona PLC (FLTR) 211.70p -1.72%Provident Financial (PFG) 890.00p -1.55%Robert Wiseman (RWD) 514.50p -1.53%Bellway (BWY) 758.00p -1.49%TalkTalk Telecom Group (TALK) 133.80p -1.47%Fenner (FENR) 222.80p -1.46%LK) 133.80p -1.47%Fenner (FENR) 222.80p -1.46%