Munich  - Russia's deputy premier said on Sunday that he was "cautiously optimistic" on relations with the US after talks with US Vice President Joe Biden in Munich - the highest-level meeting yet between a Russian official and the new US administration.

"We are cautiously optimistic but let's wait and see. We need to be realistic, (US President Barack) Obama's administration has been in power for a very limited time," Sergei Ivanov said at the end of the prestigious Munich Security Conference.

Kabul  - A bomb detonated by Taliban militants in southern Afghanistan killed four people including two American nationals on Sunday, police said.

Afghan police forces found a roadside bomb device in Nad Ali district of southern Helmand province and called the US military advisors in area to defuse it, Kamal Khan, deputy provincial police chief said.

"When the advisors and district police chief arrived at the scene, the bomb was remotely detonated, killing two US citizens, their interpreter and one Afghan policeman," Khan said.

Washington, Feb 08 : Buying life experiences - such as going for vacations or going to the theatre - rather than material possessions leads to greater happiness for both the consumer and those around them, according to new study.

The study, conducted by researchers at San Francisco State University, has shown that experiential purchases result in increased well-being because they satisfy higher order needs, specifically the need for social connectedness and vitality - a feeling of being alive.

Islamabad, Feb. 8 : United States Special Representative for Afghanistan and Pakistan, Richard Holbrooke, will be arriving here on Monday on his maiden visit after being appointed Barack Obama's special envoy to the region.

During his four day mission, Holbrooke is expected to meet President Asif Ali Zardari, Prime Minister Yusuf Raza Gilani and other top leaders.

Holbrooke's visit is being considered important as it might influence a change in Washington's strategies with regard to Afghanistan and Pakistan.

Munich, Feb. 8 : US Vice-President Joe Biden has termed Pakistan as an important ally of the United States in its `war on terror', and asked for a strengthening of ties between both countries in order to stabilise the region.

Washington will have to increase its cooperation with Pakistan as no strategy for Afghanistan can succeed without Islamabad, Biden said.

Washington, Feb 8 : Engineers at the National Institute of Standards and Technology (NIST) in the US have developed viscosity-enhancing nanomaterials that are expected to double the service life of concrete.

The nano-sized additive slows down penetration of chloride and sulfate ions from road salt, sea water and soils into the concrete.

A reduction in ion transport translates to reductions in both maintenance costs and the catastrophic failure of concrete structures.

The new technology could save billions of dollars and many lives.

The American Society of Civil Engineers estimates that Americans spend 54 billion dollars each year to repair damages caused by poor road conditions.