- Shell drops on oil sheen reports- GKN up after upgrade- World Bank cuts Chinese GDP forecastDespite an initial rise, the FTSE 100 index had fallen into the red within the opening hour with oil giant Shell providing a drag on reports of an oil sheen in the Gulf of Mexico. Eurozone peripheral bond yields have been closely watched over the last week and today won't be any different with an auction of Italian bonds due later this morning. The yield on 10-year Italian debt was down 4.1 basis points at 5.493% early on, after having risen to seven-week high of 5.7% earlier this week.Last night, the Federal Reserve's April Beige Book revealed that overall activity "continued to expand at a modest to moderate pace" in February and March. Price inflation has been "modest| but fuel prices have caused some concern, the report said.In other news, the World Bank has cut its forecast for Chinese gross domestic product (GDP) from 8.4% to 8.2%, a 13-year low. "With the economy slowing in the near term, the policy challenge is to ensure that this continues in a gradual fashion," the World Bank said. "Sufficient policy space exists to facilitate an orderly adjustment and respond to downside risks if they were to materialise."FTSE 100: Shell drops on GoM concernsAnglo-Dutch oil group Royal Dutch Shell fell sharply on the back of reports of a 10 square-mile oil sheen near to one of its platforms in the Gulf of Mexico. While no one knows where the oil came from as of yet, the company has sent a vessel to investigate. Sector peer BP was also out of favour.Engineering giant GKN was a high riser after an upgrade from Credit Suisse which upped its rating from neutral to outperform.Temporary power and temperature control solutions group Aggreko jumped early on after reporting 21% growth in underlying group revenue in the first quarter. "We continue to believe that we will deliver another year of good growth in 2012," the group said. Emerging markets asset manager Ashmore Group saw assets under management (AuM) recover strongly in its third quarter, following a fall in the first half. AuM rose 9.1% in the period, compared with the 9% fall in the first six months of the year. Shares were up over 1% early on.Power systems giant Rolls-Royce was in demand after having won another contract with the US Armed Forces, supplying power and propulsion systems for the two latest vessels in the Navy's Littoral Combat Ship (LCS) programme. FTSE 250: Hays performs strongly in Q3Recruitment firm Hays surged after saying that full-year operating profit is likely to come in at the top end of market expectations following a strong third quarter. Impressive growth in net fees overseas offset a slight decline in the UK and Ireland.Egyptian gold miner Centamin rose strongly after seeing total production grow 9% in the first quarter despite strike activity during the period.Residential property owner Grainger was also in demand after saying that completed sales from its UK and German portfolios in the first half were ahead of the prior year.FTSE 100 - RisersGKN (GKN) 200.20p +4.54%ITV (ITV) 85.15p +2.47%Croda International (CRDA) 2,117.00p +2.32%Aggreko (AGK) 2,208.00p +2.27%Johnson Matthey (JMAT) 2,313.00p +1.98%Wolseley (WOS) 2,317.00p +1.00%Burberry Group (BRBY) 1,555.00p +0.97%Polymetal International (POLY) 944.00p +0.96%Experian (EXPN) 974.00p +0.93%Kazakhmys (KAZ) 877.00p +0.92%FTSE 100 - FallersRoyal Dutch Shell 'A' (RDSA) 2,064.50p -3.57%Royal Dutch Shell 'B' (RDSB) 2,107.50p -3.55%BP (BP.) 436.65p -1.71%Man Group (EMG) 114.00p -1.47%Resolution Ltd. (RSL) 247.60p -1.20%Evraz (EVR) 349.20p -1.13%United Utilities Group (UU.) 591.50p -1.09%British Land Co (BLND) 469.70p -1.09%Severn Trent (SVT) 1,532.00p -1.03%Hammerson (HMSO) 405.20p -0.98%FTSE 250 - RisersHays (HAS) 87.45p +7.63%Grainger (GRI) 108.20p +4.44%Centamin (DI) (CEY) 65.35p +3.40%New World Resources A Shares (NWR) 423.00p +3.07%Petropavlovsk (POG) 516.00p +2.89%Fenner (FENR) 435.50p +2.71%Ferrexpo (FXPO) 289.00p +2.52%Ashtead Group (AHT) 242.40p +2.02%Bovis Homes Group (BVS) 487.20p +1.65%Imagination Technologies Group (IMG) 669.50p +1.52%FTSE 250 - FallersAfrican Barrick Gold (ABG) 354.70p -4.32%JD Sports Fashion (JD.) 770.50p -3.57%Perform Group (PER) 291.10p -2.09%Aquarius Platinum Ltd. (AQP) 133.00p -1.99%Exillon Energy (EXI) 126.10p -1.94%Carillion (CLLN) 279.20p -1.90%Ophir Energy (OPHR) 510.00p -1.83%Halfords Group (HFD) 290.10p -1.76%Cairn Energy (CNE) 321.40p -1.59%International Personal Finance (IPF) 242.70p -1.46%BC