Heritage Oil, which explores and produces oil and gas in Russia, advanced after Moscow ordered a partial withdrawal of troops near the eastern border of Ukraine. The move soothed concerns over the turmoil surrounding Russia's takeover of Crimea from Ukraine.Mining engineer Amec gained after China's official manufacturing purchasing managers' index (PMI) showed expansion in the sector in March. China's purchasing managers index (PMI) gauge for manufacturing activity rose to 53 last month from 50.2 in February, in line with analysts' expectations. A level above 50 signals growth.FirstGroup slumped after Bank of America Merrill Lynch downgraded the British transport group to 'neutral' from 'buy'.Xaar slid as the printing group continued its search for a new Chief Executive Officer (CEO) to replace Ian Dinwoodie. Last month the company made the announcement of Dinwoodie's retirement and warned of modest growth in the current financial year. FinnCap said there would be a "period of uncertainty until a new CEO is appointed".FTSE 250 - RisersAL Noor Hospitals Group (ANH) 1,148.00p +6.89%Heritage Oil (HOIL) 250.70p +5.56%Go-Ahead Group (GOG) 1,965.00p +5.47%Amec (AMEC) 1,168.00p +4.10%Carphone Warehouse Group (CPW) 338.00p +4.03%Entertainment One Limited (ETO) 342.40p +3.76%Bank of Georgia Holdings (BGEO) 2,580.00p +3.49%Fenner (FENR) 411.70p +3.29%Synergy Health (SYR) 1,425.00p +3.26%Halfords Group (HFD) 476.80p +3.25%FTSE 250 - FallersFirstGroup (FGP) 139.40p -4.46%Xaar (XAR) 898.00p -4.26%IP Group (IPO) 200.60p -3.46%CSR (CSR) 703.00p -3.10%Riverstone Energy Limited (RSE) 870.00p -2.79%Senior (SNR) 299.90p -2.47%Amlin (AML) 473.90p -2.15%Catlin Group Ltd. (CGL) 526.50p -2.14%Betfair Group (BET) 1,088.00p -1.63%Tate & Lyle (TATE) 657.00p -1.57%RD