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Farming African Wet Savannah
The global population is estimated to rise to 9.2 billion in 2050, and to feed us all, it has been calculated that we will need 70% more food production. The need to find more sustainable sources of food has led governments and intergovernmental groups such as the World Bank, the Food and Agriculture Organisation of the UN and even the Intergovernmental Panel on Climate Change to look for supplementary, and alternative, regions to grow crops, both for food and biofuels. One type of habitat that is getting a lot of focus, and is assumed to be suitable is wet savannah, particularly those in Africa. But these habitats, with their sufficient rainfall and lack of dense cover, argues Tim Searchinger in Nature Climate Change this week, are not a low environmental cost solution for converting to cropland. Based on new studies, he estimates only 2% of these areas would be suitable for growing maize with carbon levels less than the average and that the threat to biodiversity is another reason for the world’s leaders to seek alternative sources of food.

Affordable Dialysis Prize Announced
Two million people die each year because they can not get treatment for kidney failure. If your kidneys fail you need to have dialysis or in some cases a kidney transplant, but with a shortage of donors, dialysis is what most people need if they are to survive. Fiona Loud, who now works for the British Kidney Patient Association had dialysis herself, and she told Claudia Hammond how it works.
Although it is unpleasant, it does save lives. Claudia talked to professor Vlado Perkovic, executive director of the George Institute for Global Health in Australia, about why people in low income countries rarely receive dialysis and the launch of the $100,000 Affordable Dialysis Prize.

Solar Eclipse
Adam Rutherford speaks to solar scientist Dr Huw Morgan from the University of Aberystwyth, who together with his colleagues in Svalbard is going to use those precious seconds to answer one of the great enduring mysteries of the sun: why is the corona, the fiery crown around the orb, is a great deal hotter than the sun itself?

Scientists 3D Print Cars
Scientists have 3D printed a replica of a vintage 1965 Shelby Cobra sports car to showcase this rapid prototyping technology. The team at the Oak Ridge National Laboratory (ORNL) took only six weeks from start to finish. The car is not just to show that there is more than one way to make a car. The team are using the vehicle as a rolling laboratory for testing automotive technology, where new power plants, fuel cells, electronics, and other systems can be installed.

Does Money Make you Mean?
Jack Stewart heads to Los Angeles, home to many of America's rich and famous, to explore what impact wealth has on our moral behaviour. Hollywood often has plenty to say about the corrupting influence of money, but can science tell us even more.
Professor Paul Piff of the University of California explains his research, which finds that the richer a person becomes the more selfish, narcissistic and less generous they tend to be. However, not everyone is convinced that the American dream is a recipe for immoral behaviour, with opinions expressed by some rather unusual contributors – straight from the Hollywood Walk of Fame.

Digital Fingerprints
We hear from Bangladesh and trials of a mobile phone based system to help health workers track their patients. In the country millions of people do not have health records – so when a patient turns up at the clinic it can be impossible to verify who they are or find out about their medical history? One way of keeping track is to use fingerprint recognition and that is the idea behind SimPrints – a specially built system that uses a microcontroller to scan the finger, and then exchanges the scan with a central server through a mobile phone, linking a patient's fingerprints to their health records.

(Photo: African Savannah. Photo credit: AFP/Staff/Getty)
Producer: Deborah Cohen