Sewage Treatment in Africa

This week, we look into the problem of sewage and sanitation in Tanzania and reveal a new design of bicycle that could improve the cleanliness and efficiency of pit toilets in the slums of Dar es Salaam. We also hear how lasers can cut complications in cataract surgery, why some people are allergic to wine,hear the highlights from the world's biggest neuroscience meeting including the discovery of how the eye talks to the brain, and we hear how scientists have solved a long-standing mystery relating the structure of the placenta. Plus, we find out just how a caterpillar becomes a butterfly, in Question of the week!