Where both twins had the disease, there was an average of 3.66 years difference in age at onset between 25 sets of identical twins, and 8.12 years difference between 20 sets of fraternal (dizygotic) twins, suggesting genes had a role in determining when Alzheimer's was seen.

BBC: NEWS | Health | Alzheimer's risk 'is 80% genetic'

This explains a great deal of the difference between two sets of figures that Ms Moyo cites.

ECONOMIST: Economic folly

Finally, the most glaring difference between the sets of two Camp David peace talks relates to Jerusalem.

CENTERFORSECURITYPOLICY: Center For Security Policy