What is ageing? Even gerontologists don’t agree

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Researchers studying ageing disagree on just about everything — including what ageing is, whether it is a disease and when it starts. A survey of about 100 scientists working in the field found that most are clear in their own minds about what ageing is — but their perspectives don’t align with those of others. One-third of respondents considered it to be a loss of function over time, while others saw ageing as a gradual accumulation of deleterious changes — or simply as an increased chance of dying.

Nature | 5 min read

Reference: PNAS Nexus paper

The long axons that extend from neurons might be more like a ‘string of pearls’ than smooth, cylindrical tendrils. Researchers say that a technique called high-pressure freezing is able to preserve the fine details of the axon that are destroyed by other methods, making the ‘pearls’ visible to an electron microscope. And the size and spacing of the pearls seem to influence the speed at which an electrical signal travels along the axon. Others say that the structures might be a side-effect of the freezing technique. It’s “a controversial addition to the literature”, says neuroscientist Christophe Leterrier.

Science | 6 min read

Reference: Nature Neuroscience paper

A sprayable coating for textiles and other materials changes colour to help keep things cool in the heat and warm in the cold, without needing any power. The solution contains tiny capsules that change from black to white as they warm up. Researchers tested their invention on a jacket and a tent and found that it kept the temperature inside within a comfortable 19 ℃—26 ℃ range, when it was as cold as 15 ℃ and as hot as 33 ℃ outside.

Chemistry World | 4 min read

Reference: Science Advances paper

Features & opinion

How close are we to developing an artificial general intelligence (AGI) — a machine capable of the whole range of cognitive tasks that human brains can handle? Some think that the large language models (LLMs) currently out there already have some of the ingredients in place. One point in these models’ favour is their underlying transformer architecture, which can find statistical patterns in a range of information beyond text, such as audio. Yet there are also signs that transformer-based LLMs have limits. For a start, the data used to train the models are running out.

Nature | 14 min read

When US President-elect Donald Trump chose to exit the 2015 Paris climate agreement and disengage with China during his first term, it left a void. “California stepped in to help fill it,” note five authors including former California governor Jerry Brown and Zhenhua Xie, the former special envoy on climate change of the People’s Republic of China. In 2017, Brown met with President Xi Jinping and signed a series of climate and energy-focused agreements between California and several of China’s national agencies and provincial governments. It’s one example of how provinces, states, cities — and non-state actors such as businesses and academia — can maintain positive momentum on clean energy and climate action in the two countries, argue the authors.

Nature | 10 min read

Philosopher Peter Godfrey-Smith’s vivid account of the evolution of minds will fill readers with wonder — and challenge how they think about their moral responsibility to protect the planet, writes philosopher Alan Love in his review. Godfrey-Smith argues compellingly that humans have distinctive ethical responsibilities because of our uniquely powerful ability to affect the world around us.

Nature | 7 min read

Where I work

Ioannis Binietoglou is a remote-sensing policy manager at the Clean Air Task Force, pictured above testing out the latest addition to its toolkit at a coal mine in southern Greece. “The yellow box on the ground is a methane-measuring instrument, and the tablet I’m holding uses GPS data and specially designed software to generate a map of local methane,” he says. By combining local information with satellite data, researchers can track rogue emissions of the powerful greenhouse gas to the source. “For me, using the kit is almost like hunting. The methane is invisible, so you can suddenly find yourself in a plume — it’s an exciting experience.” (Nature | 3 min read)