Decoupling the two sets of exams would reduce the importance of AS-levels and the plans have drawn criticism from many teachers and universities, including Cambridge, which argues that they will "jeopardise over a decade's progress towards fairer access".

BBC: Minister rejects concerns over AS-level changes

The researchers - drawn from several universities including Cambridge, Oxford and Kings's College in London - said the findings should be used to reassure smokers attempting to quit that concerns about increased anxiety levels were unfounded.

BBC: Quitting smoking 'reduces anxiety'

Columbia is one of 13 universities, museums and institutions, including Cambridge University Press and the London School of Economics, involved in Fathom.com , a for-profit offshoot of Columbia that sells courses of various lengths and types on the Internet.

FORBES: MIT Short Circuits Distance-Ed Sellers