The Week so Far
The Chechen warlord Doku Umarov, one of Russia's most wanted men, has claimed responsibility for last month's bomb attack on Domodedovo Airport in Moscow, which left 36 dead and 180 injured. In a video posted online, he said it was a response to "Russian crimes in the Caucasus".
2. North America
The 2010 US census shows that the population of New Orleans has dropped by 29 per cent since 2000 - a sign of the long-term damage wreaked by Hurricane Katrina in 2005. It caused flooding that forced almost 200,000 residents to flee.
A row has broken out over a new law in Malawi which opponents claim will ban citizens from breaking wind in public places. However, the solicitor general, Anthony Kamanga, says that the prohibition on "fouling the air" refers only to pollution.
Military officials from North and South Korea have held their first talks since the North shelled a South Korean island in November, killing four. Relations have been tense since 46 South Koreans died when a warship was sunk in March. The talks could lay the ground for higher-levelmeetings.
There's a new dragon in the den - the entrepreneur Hilary Devey. She will replace James Caan on the next series of the BBC2 show Dragons' Den. Devey, 53, founded her pallet distribution company, Pall-Ex, by selling her car and house after banks refused to give her a loan. She is a supporter of the Stroke Association charity; she suffered a stroke in 2009.
British engineers have begun construction on what they hope will be the world's fastest car. The Bloodhound, which is powered by a rocket that is bolted to a Eurofighter-Typhoon jet engine, has been designed to reach a top speed of 1,610km/h.
Rupert Murdoch's News Corporation launched a digital newspaper for the iPad that is available only through Apple's iTunes store. The company has hired 100 journalists to work on the Daily, which costs 99 cents a week. "New times demand new journalism," said Murdoch.
The 40th anniversary of "Decimal Day", when Britain said goodbye to shillings and sixpences, falls on 15 February. France and the US decimalised in the 1790s.
Sarah Palin's attempt to trademark her name and that of her daughter Bristol has failed - for now. The US Patent and Trademark Office rejected her application as she had not signed it in person. She has until May to refile. Ronald Reagan is the only major US politician to have trademarked his name, although he did so while he was an actor.
Scientists may have discovered the genetic code that causes sleepwalking, which affects one in 50 adults. By looking at four generations of a family of sleepwalkers, the team at the Washington University School of Medicine traced the fault to a section of chromosome 20. Isolating faulty DNA could help in finding new treatments.