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Science In Action: 10/09/2010

10/09/2010

BBC World Service - Science In Action, 10/09/2010

Early warning when a species might be reaching the point of no return towards extinction

Gauging when extinction is likely; Atlantic krill; ageing the brain; X-raying immigrant’s hands to tell their real age; washing hands – saving lives

Extinction early warning
When a species goes extinct – that's it, it's gone forever.  There are thousands of animals threatened with extinction, classed as Critically Endangered.  But how can you tell which ones are in the most danger and when they are likely to reach the point where extinction is inevitable.  In an attempt to get an early warning before an animal reaches this critical 'tipping point', scientists have been looking at the population dynamics – that's the patterns and fluctuations in the number of individuals in a group of animals.  They obviously can't use rare and endangered animals, so they have been experimenting on Daphnia – a tiny crustacean-like animal in the laboratory.


Atlantic Krill
Often it's the tiny animals at the bottom of the food chain that support a whole web of life.  So when these animals are threatened, the whole ecosystem could be facing a massive crisis. This is the case of Antarctic Krill, a small crustacean found in the Southern Oceans.  The little shrimp-like animals are being overfished – they are used for fish food in commercial fish farms – but in the wild they are eaten by penguins, seabirds, fish and even whales.  Scientists are trying to learn more about their complex life cycle and behaviour in order to get an idea of how important they are and whether or not they can stop their decline.


Measuring brain development  
Tracking the development of children's bodies as they grow up is done routinely – measuring their height and weight is straight forward, and tests at school can be used to check their intellectual progress.  But how do you easily check how their brains are developing and how mentally mature they are?  Well paediatric neurologists have shown that a quick study of a brain scan can shed light on how well a child's brain is maturing and help pinpoint when things go wrong.


X-raying immigrants to check their real age
Austria has just started using X-rays to determine the age of immigrants.  People seeking asylum are often dealt with differently depending on whether they are classed as a child (under 16) or and adult. Therefore it may be in a refugee's interest to claim to be younger than they really are, or they could just have language issues that mean they can't communicate their true age.  Forensic anthropologists have been drafted in to study the X-rays of bones of the hand.  The growth plates in hand bones 'fuse' or harden at around 16 years of life.  It can be a relatively sensitive way of determining age.  But will it stand up in a Court of Law?


Moments of Genius – Stephen Fry on Hand washing
Sometimes it's the simple things that can make the most difference. This was certainly true for a theory posited by Hungarian physicist, Ignaz Semmelwiess, who in the 1840's demonstrated that hand-washing could drastically reduce the number of women dying after childbirth.

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