Optimism over the state of the US economy, fuelled by yesterday's statement from the Federal Reserve that the US economy may have seen the worse of the recession, took a knock from the release of US retail sales figures which unexpectedly showed a fall in July. The news took the shine off some of the morning's big gains on this side of the Atlantic.Miners are still in demand, however. Kazakhmys leads the mining sector higher, with Xstrata, Lonmin, ENRC, Rio Tinto, Vedanta, and Antofagasta also going well. Anglo American is higher after completing the sale of its shareholding in the South African business Tongaat Hulett to institutional shareholders for approximately $523m.Insurer Prudential said its half-year results show continued "strong performance" in what still remains challenging market conditions. IFRS operating profit before tax from continuing operations increased 6% to £688m, driven by strong underlying operating performance in Asia, together with a one-off benefit from a regulatory change in Malaysia.Travel group Thomas Cook is the biggest faller despite posting a rise in revenues in the nine months to June 30. Revenue for the nine month period climbed by 10.7% from the same period the previous year to £5.9m, while losses from operations before exceptional items and swine flu reduced by 43.4% to £49.5m. Real estate investment trust British Land is wanted on rumours that Asian investors are building up a stake. Engineer Tomkins has cut its dividend as it swung to a half year loss and said its outlook remains uncertain. The group will pay an interim dividend of 3.5 cents per share compared with 11.02 cents in the same period last year and said prevailing end market conditions and its outlook led to the decision to cut the payout.Salamander Energy, the Asia focussed oil and gas exploration firm, said it is pleased to make a discovery that could lead to its second development in the Tarakan Basin in Indonesia.Interserve, the services, maintenance and building group, has been named preferred bidder for a £60m Thames Water Utilities contract covering the creation of new facilities and upgrade works at the Riverside Sludge Digestion plant. Mobile computer software firm Psion saw pre-tax losses widen in the first half of the year but said it expects a modest improvement in revenue in the second half.Hot Tuna, the surf-oriented fashion label, has raised more than £1.1m through a placing to increase its product offering and expand into new markets.Technical plastic components supplier Carclo expects to trade in line with expectations for the full year after a satisfactory start to the new financial year despite difficult market conditions.Bookmaker technology group Alphameric has received a bid approach, sending its shares to their highest in a year-and-a-half.Henderson Morley, the AIM quoted biotechnology company, gained on news that its Koi Herpes Virus (KHV) Vaccine field study has produced positive results.Regenersis is up at a two-month high after mobile phone maker Nokia chose the handset repairer as an exclusive technical support partner to the Nokia UK Care Network.