National Grid, Vodafone and Marks & Spencer were among the blue chips that went ex-dividend today, providing a drag over the lunchtime period.Mining giant Rio Tinto is trading higher after announcing today that it is to establish a large-scale presence in commodity-hungry China with the formation of a joint venture with state-owned aluminium producer Chinalco to explore for deposits in the countryWolseley, the plumber's merchant, is firmer after third quarter revenue grew 1%, or 6% on a like-for-like basis, to £3,271m from £3,252m in the corresponding quarter of 2010. Cruise operator Carnival has placed an order for a massive 141,000-ton, 3,611-passenger cruise ship, set to be the largest in its P&O Cruises fleet. The share price has taken a knock.Drugs company AstraZeneca is edging higher after Health Canada approved Brilinta, its ticagrelor tablet product, for the secondary prevention of atherothrombotic events in patients with acute coronary syndromes. Anglo-Australian mining giant BHP Billiton is wanted after scoring a victory against the tax man in the Australian High Court. The court ruled in favour of BHP Billiton in a dispute with the Australian Taxation Office over certain tax issues relating to BHP Billiton's former Hot Briquetted Iron project at Port Hedland. ---BCFTSE 100 - RisersG4S (GFS) 292.40p +2.27%Fresnillo (FRES) 1,486.00p +1.92%Burberry Group (BRBY) 1,339.00p +1.52%Hammerson (HMSO) 486.50p +1.46%Shire Plc (SHP) 1,941.00p +1.25%GKN (GKN) 221.50p +1.14%Rio Tinto (RIO) 4,291.50p +1.10%BT Group (BT.A) 202.90p +1.05%Aggreko (AGK) 1,886.00p +1.02%Unilever (ULVR) 1,990.00p +0.96%FTSE 100 - FallersNational Grid (NG.) 603.50p -3.59%Vodafone Group (VOD) 163.05p -3.49%Lloyds Banking Group (LLOY) 50.33p -3.21%Capital Shopping Centres Group (CSCG) 396.40p -2.99%Whitbread (WTB) 1,585.00p -2.82%Marks & Spencer Group (MKS) 390.50p -2.11%Barclays (BARC) 271.45p -1.88%WPP (WPP) 745.50p -1.52%Glencore International (GLEN) 523.10p -1.51%Sage Group (SGE) 286.50p -1.27%