London open: Global concerns dent stocks early on

- Japanese concerns weigh on sentiment early on- G4S slips after first-half results, job cuts- Kingfisher lower after broker downgrade.The FTSE 100 slipped on Tuesday morning following a long weekend on concerns over the Japanese economy and uncertainty in the Eurozone."Another big factor in the fall [for the Footsie] is the increasing expectation that Ben Bernanke won't announce another round of quantitative easing in his speech at Jackson Hole on Friday and we could possibly see things pull back further over day as optimism turns quickly to doubt as we have seen all too often since 2008," said sales trader Matthew Nelson from Spreadex.The Japanese government reduced its view on personal consumption, housing construction, exports, imports and industrial output for the first 10 months of the year. "The Japanese economy is on the way to recovery at a moderate pace, partly due to reconstruction demand, while some weak movements are seen recently," the Cabinet Office said in its monthly report. JPMorgan Securities Japan and BNP Paribas are forecasting a 0.3% and 0.9% decline in third-quarter Japanese gross domestic product (GDP), respectively.Spanish GDP declined at a 1.3% annual rate in the second quarter, compared with the initial estimate of a 1% contraction.Meanwhile, European Central Bank (ECB) member Jörg Asmussen said that the EFSF bailout fund must take the lead in the purchase of any sovereign debt before the ECB steps in. "The ECB council will continue to decide in full independence whether, when and how it will purchase bonds on the secondary market," he said.G4S slips after revealing Olympics costs and job cutsSecurity giant G4S fell after expressing disappointment over the problems related to its Olympics contract, saying that it will incur a £50m loss on the contract in the first half. Meanwhile, the company said that a restructuring of its overhead structure will lead the loss of 1,100 jobs. Nevertheless, the firm revealed that turnover at constant exchange rates rose 7.5% while profits were flat.Miners were firmly out of favour this morning on concerns over the Japanese economy. BHP Billiton fell after announcing the sale of its Yeelirrie uranium deposit in Western Australia to Cameco for $430m. BHP and sector peers ENRC, Kazakhmys and Vedanta were also lower after Morgan Stanley reduced its target price for all four stocks.Glencore fell after saying that China is going to take longer than expected over its review of its acquisition of agriculture business Viterra.B&Q owner Kingfisher was a heavy faller after Bank of America Merrill Lunch downgraded its rating on the stock to 'underperform'.Drugs giant AstraZeneca was flat after saying that it has appointed Roche's Chief Operating Officer as its new Chief Executive Officer. Meanwhile, the firm also announced that the European Commission has granted marketing authorisation to its ZINFORO treatment.Bunzl, the international distribution and outsourcing group, fell despite saying that pre-tax profits and revenues in the first half rose 9% and 7%, respectively.FTSE 100 - RisersCarnival (CCL) 2,124.00p +1.53%Barclays (BARC) 188.65p +0.77%Smiths Group (SMIN) 1,047.00p +0.58%Severn Trent (SVT) 1,745.00p +0.52%Tesco (TSCO) 340.70p +0.50%United Utilities Group (UU.) 714.50p +0.49%Standard Chartered (STAN) 1,419.00p +0.42%Hargreaves Lansdown (HL.) 622.00p +0.40%SABMiller (SAB) 2,785.00p +0.38%BT Group (BT.A) 216.00p +0.37%FTSE 100 - FallersKingfisher (KGF) 274.00p -4.10%G4S (GFS) 258.40p -2.93%Antofagasta (ANTO) 1,106.00p -2.56%Evraz (EVR) 240.50p -2.55%Eurasian Natural Resources Corp. (ENRC) 330.80p -2.39%Kazakhmys (KAZ) 645.00p -2.35%Rio Tinto (RIO) 2,849.50p -2.08%Vedanta Resources (VED) 906.50p -1.95%Marks & Spencer Group (MKS) 364.50p -1.94%Bunzl (BNZL) 1,091.00p -1.80%FTSE 250 - RisersYule Catto & Co (YULC) 150.50p +6.14%Ted Baker (TED) 990.00p +2.38%Dialight (DIA) 1,099.00p +2.33%Interserve (IRV) 359.80p +1.90%Moneysupermarket.com Group (MONY) 133.20p +1.68%Homeserve (HSV) 215.50p +1.56%Kier Group (KIE) 1,324.00p +1.53%Regus (RGU) 98.60p +1.28%FirstGroup (FGP) 246.50p +1.23%Fidelity European Values (FEV) 1,149.99p +1.14%FTSE 250 - FallersChemring Group (CHG) 325.60p -12.12%Cairn Energy (CNE) 283.10p -4.45%Heritage Oil (HOIL) 192.00p -3.95%Hochschild Mining (HOC) 420.00p -3.93%Afren (AFR) 125.00p -3.77%NMC Health (NMC) 190.00p -3.55%Bodycote (BOY) 333.70p -2.88%Shanks Group (SKS) 88.30p -2.43%Petropavlovsk (POG) 375.00p -2.42%Lonmin (LMI) 626.00p -2.19%BC