With many parts of the country seeing large snowfalls we ask what's driving our current weather? What factors need to be in place to create snowfalls, and how do these differ from sleet or frozen rain? And we address the impact of climate change, while a series of weather events might show a pattern, at what point should we go looking for explanations beyond natural events?

Dutch Elm Disease laid waste to millions of British Elm trees back in the 1970's, Now a new tree bacteria which mimics the effects of drought has spread from the Americas to Europe. It has already been detected in some tree imports to the UK. Unlike Dutch Elm Disease it affects a huge variety of trees and shrubs, from mighty oaks to fruit trees and Lavender bushes. New directives have just been introduced to try and halt its spread.

Can we beat dementia? Research from the US amongst people in their 80's and 90's provides grounds for optimism, showing that elderly people with good memories have brain structures which can be more developed than those of people 30 years younger. And yet at the same time they may carry factors usually associated with dementia.

And how violent are we? Compared with our past that is. Research from collections of gruesome medieval remains paint a picture of a violent society, where men and women commonly carried weapons and inflicting or receiving severe wounds may have been a part of daily life. And yet other studies suggest this level of violence is actually lower than that experienced in some societies today.

Marnie Chesterton presents.