London's blue chips have opened higher after US indices powered forward again as investors took heart from the latest round of results in the third quarter season.Online retailer Amazon keep the momentum going after the US markets closed, as net income rose 69% year on year to $199m on sales of $5.45bn. Third quarter net income last year was $118m, while sales totalled $6.7bn. In the UK, strong demand for its high definition service helped satellite broadcaster BSkyB add a net 94,000 subscribers in the last three months, with revenues and profits also ahead. New Sky+HD users tripled to 287,000 in the three months to September to bring the total to 1.6m. Total Sky subscriptions now stand at 9.54m after the last three months, despite the cancellation rate or churn rising to 11.3% from 10.9%. Total additions for the quarter were up 8% to 362,000. Engineering company Invensys said its railway subsidiary has won a contract for the Metro system in São Paulo, Brazil. Invensys Rail will install its Sirius Communication Based Train Control (CBTC) system on line 8, 10 and 11 of the city's metro system.Conditions are set to remain mixed for underwriter Brit Insurance after a three months that saw UK premiums rise strongly but elsewhere remain under pressure.Laundry and workwear firm Davis Service Group said trading has continued broadly in line with the trends seen in the first half of the year, with revenue modestly ahead of the nine months period in 2008 and profits maintained at a similar level. Financial trading software specialist Fidessa said it continues to make good progress across all regions and believes that it can deliver strong growth for 2009 as a whole. Speciality plastic and fibre products supplier Filtrona had a slightly better than expected third quarter than management had been expecting, on the back of a strong performance by its Porous Technologies division.Foam maker Zotefoams expects underlying profits to beat market foreasts for this year after sales picked up in the second half.Metals group Delta's trading performance has weakened since the half year though it remains on track to hit market forecasts.