Greene King was a big faller after going ex-dividend, meaning investors no longer have the right to the group's latest dividend. Recent updates from Aquarius Platinum have been increasingly gloomy about the difficulties of operating in South Africa so it was no surprise when the platinum miner announced it had fallen into the red. Shares slipped 1.25%.Defence technology group Cobham fell despite reporting robust growth in its core businesses in the first half, although it did say that it is approaching 2013 'with caution', particularly as its order intake slipped by over a fifth. Nevertheless, the firm hiked its interim dividend per share by 33% from 1.8p to 2.4p. Heritage Oil was in the top position after UBS upped its target price on the stock from 190p to 250p and retained its buy rating. FTSE 250 - RisersHeritage Oil (HOIL) 183.00p +22.98%BBA Aviation (BBA) 184.70p +3.76%Stobart Group Ltd. (STOB) 121.70p +2.27%JD Sports Fashion (JD.) 684.50p +2.01%Melrose (MRO) 233.70p +1.83%Hansteen Holdings (HSTN) 74.50p +1.78%BH Global Ltd. USD Shares (BHGU) 11.5 +1.77%Cable & Wireless Communications (CWC) 32.63p +1.75%Shanks Group (SKS) 80.30p +1.65%Computacenter (CCC) 375.80p +1.57%FTSE 250 - FallersGreene King (GNK) 565.00p -5.60%Cobham (COB) 225.60p -5.41%Cairn Energy (CNE) 294.30p -4.88%Talvivaara Mining Company (TALV) 146.80p -4.80%Bwin.party Digital Entertainment (BPTY) 92.95p -4.27%Petra Diamonds Ltd.(DI) (PDL) 109.90p -4.10%Homeserve (HSV) 217.90p -3.24%Marston's (MARS) 108.90p -3.20%International Personal Finance (IPF) 295.00p -3.12%Bumi (BUMI) 368.30p -3.08%NR