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A group of sleeping laboratory rodents in a cage.

In some earlier animal experiments, the brain’s waste-clearance system appeared to be more active during sleep. (unoL/iStock via Getty)

Does sleep cleanse the brain?

A study seems to cast doubt on the theory that we need sleep to clean waste products from the brain. In mice, sleep apparently slows down, rather than speeds up, their brain’s ability to remove a dye. Some researchers see this as a blow to the sleep clearance theory. Critics say that the study’s method for measuring dye removal could have damaged the brain’s waste-clearance system, and is too different from previous studies to credibly challenge them. The brain could even have different ways to clear small compounds such as a dye and large ones such as the beta-amyloid protein linked to Alzheimer’s disease, says brain circulation specialist Erik Bakker.

Science | 5 min read

Reference: Nature Neuroscience paper

South Africa elections: ‘Stop xenophobia’

As South Africa votes in today’s general election, scientists hope that the next government will halt declining funding and protect international researchers from attacks. Some have voiced concerns that xenophobic rhetoric used during the election campaign could stoke further violence against international university staff and students, particularly those from elsewhere in Africa. “Colleagues [from other African countries] tell us outright: ‘We don’t see a long term future for ourselves here,’ given this creeping xenophobia on campuses as well as in the broader community,” says education researcher Jonathan Jansen.

Nature | 6 min read

Autism triples risk of ‘parkinsonism’

People with autism, intellectual disabilities or both are three times more likely than the general population to develop Parkinson’s-like symptoms as they age — such as tremors and sudden freezing while walking. The study, the largest of its kind, followed almost a quarter of a million people in the United States aged 45 and older. It’s not clear whether this parkinsonism is linked to autism by an as-yet unidentified facet of brain health or development, or whether it could be affected by antipsychotic drugs given to some children with autism.

Nature | 5 min read

Features & opinion

The AI revolution is coming to robots

Artificial intelligence (AI) algorithms, such as those that power chatbots, could imbue robots with the common-sense knowledge they need to cook dinner or run errands. “I wouldn’t be surprised if we are the last generation for which those sci-fi scenes are not a reality,” says robotics researcher Alexander Khazatsky. There are already some impressive demonstrations of AI-powered robots, but the dearth of movement data for robots to learn from, coupled with temperamental hardware, means that it could be a while until we can rely on droid helpers. And there are concerns that AI systems’ biases and mistakes could cause physical harm. “Until we have confidence in robots, we will need a lot of human supervision,” says AI researcher Keerthana Gopalakrishnan.

Nature | 11 min read

How to stop immune system sabotage

Researchers are trying to prevent the immune system from attacking the relatively harmless viruses that are used in gene therapy to shuttle restorative genes into cells. Gene therapy can treat conditions including blood disorders, and degenerative eye and muscle diseases. But many people can’t receive more than one dose because they have antibodies against the gene-therapy viruses. Animal studies suggest that it’s possible to dampen the body’s ability to disable the viruses. There are also attempts to use other viruses that can better evade the immune system, or deliver genes inside protective fatty particles.

Nature | 6 min read

What to do when funding runs out

Only one-quarter of grant proposals to major funders are successful, so funding gaps are common and stressful. Bridge-funding programmes can allow researchers to gather more data and bolster their next, larger grant application. Some institutions offer in-house ‘sabbaticals’ — funded positions to work with a colleague from a different department — or support scientists with money for research that has commercial potential. It’s also worth looking beyond the big funders, says research director Bryony Butland: “You just need to think about it a little bit differently, speak a slightly different language, but relate to their challenges and opportunities in a way that maybe you haven’t thought about before.”

Nature | 11 min read

Infographic of the week

A periodic table infographic of “the 90 natural elements that make up everything”

The European Chemical Society has updated its version of the periodic table to include each element’s sustainability credentials. The table colour-codes the elements to show their availability and their risk of being overused. (EuChems (CC BY-ND))


“When you are the only one in the room that looks like you, it feels different.”

Black mathematician Freeman Hrabowski invited some of his white colleagues to spend a day at a historically Black university. Hrabowski’s development programme for minority students became a leading model for increasing diversity among science graduates. (Nature | 6 min read)