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SCIENCE POST 9/11

It's been a decade since 9/11, and the attacks on the Twin Towers in New York, and the Pentagon in Washington DC. The United States created the Department of ³ÉÈË¿ìÊÖland Security and its Science and Technology Directorate to help prevent a similar attack. In an article in the journal Nature this week a former Chief Scientist of the US Senate Foreign Relations Committee writes a scathing criticism of its track record. Peter Zimmerman talks to Jon Stewart.

AUSTRALOPITHECUS

Next a new insight into human evolution, and when and why we started to walk on two legs. A collection of papers in the journal Science have revealed new details about a species of Australopithecus - a primitive type of hominin, or human ancestor. If you've seen or heard stories about Lucy you might have an idea what Australopithecus looks like - she's the most famous fossil example found. They had hefty jaws and huge faces, and lived two to four million years ago. Now scientists have done a careful analysis of the brain, hands, pelvis, and feet of Australopithecus sediba – and it's looking like it existed at a key moment in evolutionary terms. The transition between apes and humans. Paleoanthropologist Will Harcourt Smith is from the American Museum of Natural History and the City University of New York, Lehman College tells us more,

GLOBAL WARMING AND ALPINE TREES

Since 2008, hi-tech heaters, soil sensors, conduits and cables have become part of the pristine Colorado Rocky Mountain landscape. As part of a research project called the Alpine Treeline Warming Experiment, researchers from California in the US are simulating what they believe future climate conditions will be like, and seeing the effect on tree seedlings. Science in Action reporter Ellen Mahoney joined the team as they travelled high into the alpine tundra of the Rockies to check on progress.

ATOMIC CLOCK

Scientists have found that the UK's official timekeeping is the most accurate in the world. The atomic clock at the National Physical Laboratory has been put through its paces and is currently far more accurate than any other on the planet. ³ÉÈË¿ìÊÖ science and technology reporter Jason Palmer went to see it for us.