Essar Energy's shares rallied after the company narrowed its losses as revenues grew on the back of higher refining volumes at the energy company's Refining and Marketing (R&M) India business.Man Group advanced as the company held an analyst presentation outlining that it intends to revise the format of its quarterly funds under management disclosures in its interim management statement in August. In contrast, Centamin's stocks plunged after gold prices edged lower on fears of a cash crunch in China as Goldman Sachs cut its growth forecast for the world's second largest economy.Kazakhmys, a top shareholder of Eurasian Natural Resources Corp. (ENRC), retreated following news it supported a takeover bid of ENRC by its founders and the Kazakh government.FTSE 250 - RisersEssar Energy (ESSR) 122.70p +3.11%Man Group (EMG) 81.10p +2.92%Kenmare Resources (KMR) 25.00p +2.88%Anite (AIE) 132.50p +2.08%Computacenter (CCC) 414.80p +1.42%Interserve (IRV) 490.70p +1.36%Spirent Communications (SPT) 136.80p +1.11%JPMorgan Emerging Markets Inv Trust (JMG) 542.00p +0.74%F&C Commercial Property Trust Ltd. (FCPT) 112.20p +0.63%ICAP (IAP) 381.70p +0.61%FTSE 250 - FallersCentamin (DI) (CEY) 31.89p -10.45%Kazakhmys (KAZ) 245.30p -8.95%Dixons Retail (DXNS) 39.06p -8.78%Ashtead Group (AHT) 601.00p -6.60%Fidelity China Special Situations (FCSS) 80.25p -6.14%Sports Direct International (SPD) 507.50p -5.58%Salamander Energy (SMDR) 147.30p -5.15%Thomas Cook Group (TCG) 115.10p -4.88%Capital & Counties Properties (CAPC) 295.00p -4.69%Barr (A.G.) (BAG) 511.50p -4.48%RD