Scientists have used a bacteria that commonly infects us to track how ancient humans spread to the Americas from Siberia. And other scientists have discovered a new species of hyrax in the forests of Africa by listening to their barks...

In 1984, Dr. Barry Marshall had a theory about ulcers that he couldn't convince the science community of. So, he took matters into his own hands... or stomach, and infected himself with a potentially deadly bacterium.

Stomach ulcer, endoscope view. Also known as a peptic, or gastric, ulcer, it is erosion of the stomach lining, which leads stomach acids to attack the stomach wall. Most such ulcers are associated with infection by the bacterium...

1. Pan to delegates entering hall

2. Goran Hansson, Chairman of Nobel Committee at lectern, welcomes media, introduces Professor Hans Jรถrvall, Secretary of Nobel Asse
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3. SOUNDBITE: (English) Professor...