Of the 700 teachers who completed the ATL questionnaire, 52% thought pressure to be popular on social networking sites was also a source of strain.

BBC: Pupils 'under greater pressure'

As ETFs have exploded in popularity, they also have become the source of concern that the structure distorts prices or would break under the strain of investors bailing out en masse.

WSJ: Gold ETFs Shine in Midst of Tumult

Eggs have not been a major source of infection in humans for this particular strain of salmonella, enteritidis, in the last twoor three years, said Patrick McDonough at Cornell University's School of Veterinary Medicine.

CNN: STORY HIGHLIGHTS

WHO's global stockpile of Tamiflu (about 3m doses) could be deployed to the site of first emergence of a pandemic strain and used to eliminate it at source.

ECONOMIST: Avian influenza