The New York Post is the latest newspaper to cross the iPad barrier, with a new, full-content tablet edition readers will be able to purchase as a monthly or annual subscription.

FORBES: New York Post to Sell Subscriptions on the iPad

The road will cross a small stream and continue parallel to the stream for some time before the first blue cross appears on the side barrier of a small cement bridge.

BBC: Romania��s Prince Charles walk

Substances that cannot cross this barrier are unlikely to make effective treatments for a brain disease.

ECONOMIST: Creutzfeldt-Jakob disease

"There used to be this barrier between the States and the UK - a border you couldn't cross, " he told the BBC.

BBC: Brits 2013: The real winners and losers

Mr Schwartz is a former director of the Institut Pasteur in France, and his book maps out with great clarity the scientific investigation into how scrapie a disease that has long been known to afflict sheep came to cross the species barrier to cows, and then from cows to humans.

ECONOMIST: Food safety