(ShareCast News) - London's FTSE 100 was up 0.2% to 6,091 by 1352 BST, recovering from earlier losses, although worries about a slowdown in China continued to unsettle investors.Engineering company Weir got a boost from M&A news in the sector, after it emerged that oilfield services group Schlumberger has agreed to buy Cameron International Corp in a deal valued at $14.8bn.Meanwhile, broker notes were working their magic on Wednesday.Royal Bank of Scotland was on the front foot after Morgan Stanley lifted the stock to 'overweight' from 'equalweight' and raised its price target to 400p from 345p. "RBS has repeatedly disappointed market expectations on earnings power as the definition of 'core' has been whittled away. Now, as the final layers are peeled away a slimmed-down UK/Irish retail and commercial bank with top three position in its key markets should start to emerge by 2018," it said.Miner BHP Billiton was also having a good day after RBC Capital Markets upgraded the stock to 'sector perform' from 'underperform'. The bank said it likes both the improved-upon cost targets for BHP as well as its renewed focus on free cash cover of the dividend. "We think BHP's new capex flexibility and willingness to take opex and capex lower over the coming two years leaves it in good stead to deal with a prolonged period of commodity price weakness."Chip maker ARM Holdings rose after Bernstein upped its stance on the stock to 'market perform' from 'underperform' with an unchanged target price of 800p, noting that since its last peak at the end of March, the stock has significantly underperformed the wider market. Bernstein said the stock has dropped 25% since March as the company reported a disappointing second quarter and negative newsflow from the handset market intensified steadily. However, added near-term expectations have come down, "making the risk reward of shorting the stock into the next set of numbers unattractive."On the downside, shares in media group WPP fell. Although the company reported a 44.5% jump in first-half pre-tax profit and a 6.8% rise in revenue, analysts pointed to a slowdown in its sales in Europe and emerging markets. "Overall, these are a very mixed set of results from WPP. While the profit and dividend growth is clearly good news for those invested, the slowdown in key emerging markets is concerning if not unexpected," said Ian Forrest at The Share Centre.RisersWeir Group (WEIR) 1,365.00p +2.48%BHP Billiton (BLT) 1,038.50p +1.71%TUI AG Reg Shs (DI) (TUI) 1,154.00p +1.32%Tesco (TSCO) 187.95p +1.05%Carnival (CCL) 3,230.00p +1.00%Royal Bank of Scotland Group (RBS) 324.40p +1.00%ARM Holdings (ARM) 904.50p +1.00%Capita (CPI) 1,217.00p +0.91%International Consolidated Airlines Group SA (CDI) (IAG) 522.00p +0.77%BP (BP.) 337.40p +0.61% FallersWPP (WPP) 1,325.00p -2.72%BG Group (BG.) 936.70p -2.49%Johnson Matthey (JMAT) 2,616.00p -2.42%Hikma Pharmaceuticals (HIK) 2,226.00p -2.20%Persimmon (PSN) 2,020.00p -1.85%Experian (EXPN) 1,068.00p -1.84%Fresnillo (FRES) 628.00p -1.80%Burberry Group (BRBY) 1,368.00p -1.72%Smiths Group (SMIN) 1,072.00p -1.65%Aberdeen Asset Management (ADN) 309.40p -1.59%