Shares in Chemring are lower ahead of the military decoy specialist's preliminary results tomorrow.Retailers are mixed, with department store Debenhams and carpet and tiling retailer Carpetright higher but video games retailer Game in the red. Newspaper publisher Trinity Mirror and directories group Yell have taken heart from an Institute of Practitioners in Advertising survey saying ad spending could rise for the first time in more than two years.FTSE 250 - RisersMelrose Resources (MRS) 350.00p +9.03%PartyGaming (PRTY) 272.40p +4.49%Heritage Oil (HOIL) 534.00p +3.89%COLT Telecom Group S.A. (COLT) 140.90p +3.68%Ferrexpo (FXPO) 235.80p +2.75%Yell Group (YELL) 39.02p +2.68%Trinity Mirror (TNI) 169.30p +2.61%SVG Capital (SVI) 144.80p +2.40%Debenhams (DEB) 69.30p +2.36%Carpetright (CPR) 954.00p +2.20%FTSE 250 - FallersComputacenter (CCC) 300.40p -3.00%Game Group (GMG) 98.05p -2.92%PayPoint (PAY) 429.50p -2.39%Electrocomponents (ECM) 174.90p -2.29%Regus (RGU) 96.65p -1.78%F&C Commercial Property Trust (FCPT) 91.00p -1.62%Evolution Group (EVG) 134.10p -1.61%Chemring Group (CHG) 2,875.00p -1.61%Fenner (FENR) 195.70p -1.61%Galiform (GFRM) 86.25p -1.43%