Daily briefing: Fossilized footprints show people’s first steps into the Americas

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Fossilized human footprints might be the oldest direct evidence that people lived in the Americas thousands of years earlier than thought — as early as 23,000 years ago. Researchers analysed pollen and sediment from the footprints and found that their ages matched estimates from 2021 that were based on the ages of seeds stuck in the fossils. The finding supports the idea that people skirted down the Pacific coast of the Americas after crossing the Bering land bridge, rather than waiting until ice-age glaciers retreated from inland routes. The timeline is also supported by indirect evidence, such as pendants carved from animal remains, but the footprints in New Mexico are special because they were undoubtedly made by people.

Associated Press | 3 min read

Read more: Ancient footprints could be oldest traces of humans in the Americas (Nature | 6 min read, from 2021, Nature paywall)

Reference: Science paper

Scientists in Poland are exploring the possibility of testing whether a woman has taken the abortion drugs mifepristone and misoprostol. The researchers say that their work is untainted by politics, but others worry that the technique could be used by prosecutors in Poland and other countries where abortion is, in most cases, illegal.

Nature | 7 min read

Bird-flu-resistant chickens have been created using CRISPR gene editing. When exposed to the flu virus, nine out of ten of the animals remained uninfected and didn’t pass the virus to other birds. Researchers modified a gene encoding a chicken protein that the virus needs to replicate. But this prompted the virus to start replicating using other proteins in the same family, which the researchers think could be addressed with more edits. “We must be careful not to facilitate adaptations of the virus that make it more dangerous than it [already] is,” says virologist and study co-author Wendy Barclay.

Large language models (LLMs), such as ChatGPT, could become regular assistants for writing manuscripts, peer-review reports and grant applications. These artificial-intelligence (AI) tools could change how scientists interrogate and summarize results, producing ‘papers on demand’ from experimental data and vastly expanding the scope of meta-analyses and reviews. But publishers worry that LLMs’ propensity to make up information might lead to a flood of error-strewn manuscripts — and possibly AI-assisted fakes. And because LLMs trawl Internet content without concern for bias, consent or copyright, their use is “automated plagiarism by design”, suggests cognitive scientist Iris van Rooij.

Nature | 11 min read

Each Nipah outbreak gives the deadly virus the chance to produce a strain that could spread more effectively — and there are no vaccines or treatments available yet. Smart policy changes can help to quell the risk of a pandemic, says epidemiologist Thekkumkara Surendran Anish. An early detection system in countries likely to have Nipah virus reservoirs in fruit bats, he explains. Public-awareness campaigns aimed at stopping behaviours that could bring people into contact with bat saliva can also help to prevent spillover of the virus.

Nature | 5 min read

The influence of statistician Calyampudi Radhakrishna Rao can be partly appreciated by perusing the many advances that carry his name: the Cramér-Rao inequality, used to estimate unknown parameters of a statistical population, such as the average blood-pressure reduction caused by a new drug. Another is the Rao-Blackwell theorem, an algorithm that derives rules for making such estimations. A third is the Fisher-Rao distance — a metric for the dissimilarity between two probability distributions — which gave rise to ‘information geometry’, a technique that enables information to be extracted from data sets with many variables. Rao, who published seminal papers while he was just in his twenties, has died aged 102.

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