Dr Chris Smith and the Naked Scientist team present the latest science news, analysis and breakthroughs. In this week's programme: scientists give mice a rat's sense of smell; we find out why some of China's biggest cities are sinking; and 14 years after disaster struck in the Gulf of Mexico, how laser-treated cork may be able to help us to clean up oil spills in future. Plus, a special look at ADHD, attention deficit hyperactivity disorder, as we find out what it is, who's got it and how science can help us to better manage it.