Migrants usually help host-communities, bringing new skills, new vigour, demographic infill and fresh ideas.

ECONOMIST: Immigration: No entry | The

Prince Nayef is targeted because of the new vigour, not always applied with accuracy, with which his security forces have chased al-Qaeda's fans.

ECONOMIST: Are the royal family the terrorists' target?

Now those tools are available their use in economics pioneered by specialists in industrial organisation and trade so economists can breathe new vigour back into the lifeless body of geography.

ECONOMIST: Knowing your place

Recent student demonstrations in Iran a particularly emotional one was planned for this week but the security services kept it from getting out of hand have given the stations new vigour.

ECONOMIST: Telling it to Iran

Pakistan's Western allies, though glad at the evidence of new vigour in Pakistan's fight against the Taliban, are privately concerned about the killings, which risk sullying the army's recent gains.

ECONOMIST: Pakistan's Swat valley

This new-found vigour comes at a time when the big phone companies have at last begun to recover from the ill effects of the industry's last burst of exuberance.

ECONOMIST: Telefonica looks to Europe | The

Already they are jostling for deposits with new-found vigour.

ECONOMIST: Can the success of money funds last?

But thanks to the vigour of the new titans, it will stay above its 30-year average of 3.5%.

ECONOMIST: Recession in America

Moreover, the Liberal Democrats have long advocated a review of drugs law, and several prominent Tories have shown a desire for fresh thinking most notably Alan Duncan, the party's new chief spin-doctor, who has argued with vigour for drug legalisation.

ECONOMIST: Shopping for a drugs policy