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Nobel-prizewinning chemist Frances Arnold and other senior scientists share what they learnt from the experience of retracting a paper. Plus: Early Earth might have been a ‘water world’ almost devoid of land and WHO raises the global alert level for coronavirus.
Early Earth might have been covered with ocean and almost devoid of land. Researchers examined the ratio of oxygen isotopes in a 3.2-billion-year-old slab of the planet’s crust that is exposed in Western Australia. High levels of oxygen-18 in the oldest rock suggest that continents (which absorb that isotope) might not have emerged until between 3 billion and 2.5 billion years ago.
• The World Health Organization (WHO) has raised the global alert for COVID-19 to ‘very high’ — the highest possible level short of calling it a pandemic. The assessment is based on the continued increase in cases and affected locations, and the difficulties that regions such as Iran and Italy are facing in containing the spread. “We still have a chance of containing this virus, if robust action is taken to detect cases early, isolate and care for patients and trace contacts,” said Tedros Adhanom Ghebreyesus, director-general of the WHO. (Nature | Continuously updated)
“Someone I admire retracted a very important paper when I was a young scientist,” says Nobel-prizewinning chemist Frances Arnold, who retracted a paper in January. “I wanted to pay that lesson forward.” Arnold and three other senior scientists share what they learnt from the experience of retracting flawed papers.
Around one-third of the global human population is infected with the single-celled organism Toxoplasma gondii, which in some cases causes the incurable disease toxoplasmosis. Researchers have found a single gene that controls the conversion of the parasite into a form that chronically infects the human brain. Targeting the gene, BFD1, shows real potential for making progress in the development of drugs or vaccines, writes biochemist Eva-Maria Frickel.
Physicist Freeman Dyson, who died on Friday at the age of 96, spoke to physicist Katie Mack last year about the end of the Universe. (The New York Times)