Nature Podcast

00:31 How open are ‘open source’ AI systems?Many of the large language models powering AI systems are described as ‘open source’ but critics say this is a misnomer, with restricted access to code and training data preventing researchers from probing how these systems work. While the definition of open source in AI models is yet to be agreed, advocates say that ‘full’ openness is crucial in efforts to make AI accountable. New research has ranked the openness of different systems, showing that despite claims of ‘openness’ many companies still don’t disclose a lot of key information.Nature News: Not all ‘open source’ AI models are actually open: here’s a ranking06:12 Why longer freight trains are more prone to derailmentIn the US, there are no federal limits on the length of a freight train, but as companies look to run longer locomotives, questions arise about whether they are at greater risk of derailment. To find out, a team analysed data on accidents to predict the chances of longer trains coming off the tra