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Excavations at the site in Utah, where charred tobacco seeds were found among the contents of a 12,300-year-old hearth.Credit: D. Duke et al./Nat. Hum. Behav.
Tobacco remnants in a prehistoric fire
Hunter-gatherers in North America might have been using tobacco around 12,300 years ago — 9,000 years earlier than was previously documented. Archaeologists found four burnt tobacco-plant seeds in an ancient hearth excavated in Utah. The seeds themselves were too small and fragile to be dated, but other burned woody material in the hearth is around 12,300 years old. “People in the Pleistocene likely smoked tobacco or chewed tobacco in a similar fashion to how it’s used today,” says archaeologist Jaime Kennedy.
Reference: Nature Human Behaviour paper
China’s COVID vaccines show waning immunity
The CoronaVac and Sinopharm vaccines, developed in China, have been enormously important in fighting the pandemic, particularly in less wealthy nations. But studies suggest that the immunity from two doses of either vaccine wanes rapidly, and the protection offered to older people is limited. This week, the World Health Organization advised that people over 60 should receive a third dose of the same or another vaccine to ensure sufficient protection.
Reference: WHO announcement
Investigation of star neuroscientist in Chile
High-profile neuroscientist Claudio Hetz, at the University of Chile in Santiago, has been found not guilty of scientific fraud — although an investigation revealed that there were altered images in a number of his research publications. Some members of Chile’s research community say that, in their opinion, the scientist’s actions set a poor example for researchers in the country, and they question why his punishment wasn’t harsher. Hetz tells Nature he accepts full responsibility, but points out that any image manipulations did not ultimately affect his results.
On the cusp of an apple
Physicists analysed 100 apples plucked from an orchard at the University of Cambridge, UK, to determine the physics underlying the shape of the ‘cusp’ where the stem grows. The cusp is an example of a singularity: a point at which a function becomes infinite or ill-defined. In this case, rather than infinite density at the centre of a black hole, for example, the singularity is created by the abrupt change in the orientation of the apple’s surface at the base of the stalk. “What is exciting about singularities is that they are universal,” says biophysicist Thomas Michaels. “The apple cusp has nothing in common with light patterns in a swimming pool, or a droplet breaking off from a column of water, yet it makes the same shape as they do.”
Reference: Nature Physics paper
Features & opinion
‘I hope you die’: COVID scientists face abuse
A survey by Nature of more than 300 scientists who have spoken publicly about COVID-19 has found wide experience of harassment or abuse. Some high-profile examples of harassment have been extreme: US public-health leader Anthony Fauci needs security guards because of death threats, and Belgian virologist Marc Van Ranst and his family were placed in a safe house when a military sniper threatened to target virologists. Nature’s survey suggests that even though researchers try to shrug off abuse, it might already have had a chilling effect on scientific communication.
Read more: COVID scientists in the public eye need protection from threats (Nature Editorial | 4 min read)
Source: Nature analysis
The geometry of love and grief
Mathematician Michael Frame’s lifelong love of geometry informs a personal meditation on grief. The childhood loss of his aunt set him on his career path, including a long collaboration with fractal geometer Benoit Mandelbrot. Even the moment of epiphany on first understanding any beautiful mathematical idea is tinged with sadness, because it is unrepeatable. Ultimately, geometry shows how reframing the fractal, repeating experience of grief can help salve the pain that is fundamental to a life lived with love.
