Nature, Published online: 11 September 2026; doi:10.1038/d41586-026-02901-xTraces of the psychoactive compound arecoline suggest that two people regularly sucked on psychoactive betel nuts. Plus, what motivates people to take action on climate change and the promise of nasal vaccines.

Nature, Published online: 09 September 2026; doi:10.1038/d41586-026-02867-wThe AI giant claims to have solved one of maths’ trickiest problems, but questions swirl over should get the credit. Plus, an atlas of every single DNA letter mutation in humans and why more bioengineered microorganisms aren’t making it out of the lab.