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Around the time of birth, the developing human brain mysteriously clears out a vast number of mutation-riddled neurons. Researchers found that more than one-quarter of neurons sampled from human fetuses had some kind of chromosomal abnormality, but this percentage plummeted to 6% in the brains of babies who’d just been born. The findings reveal a new mechanism for regulating how many neurons a person has and for deciding which fetal neurons are allowed to persist in the brain, says paediatric neurogeneticist and study co-author Diane Shao.

Nature | 5 min read

Reference: Nature paper

A new report suggests that it might be possible to launch a swarm of satellites that reflect sunlight away from the planet to cool the global temperatures in as few as 20-40 years. The timeline of such a ‘planetary sunshade’ would depend on the rate at which heavy-lift rockets that could carry the materials into deep space are developed, the report says. A lot of people think this idea is “just fantasy”, says space-systems engineer Chantal Cappelletti. But the falling cost of space launches has made the prospect of space-based solar geoengineering seem more realistic.

Nature | 6 min read

Reference: Planetary Sunshade Institute report

Researchers have identified three warning signs that suggest journals might be engaging in suspicious publishing activities. These red flags are, for any given journal in a single year: a doubling of publication output; having more than 70% of published articles originating from a single country; and having at least 15% of articles flagged by the Problematic Paper Screener, a free online tool. Using titles on the database OpenAlex, the team identified 3,753 journals that met at least one of these criteria. These signals can help to identify journals that merit further investigation — but do not prove that titles are problematic, say the study authors.

Nature | 5 min read

Reference: Zenodo preprint (not peer reviewed)

The results of a trial that intentionally infected volunteers with a weakened strain of dengue virus hint at why the disease hits harder in people who are infected for a second time — an issue that has stymied the development of a dengue vaccine. Researchers found that people who’d had dengue before tended to have higher viral loads and more hyperinflammatory signals on second exposure than did people who had never had the virus. The people with the highest viral load had fewer antibodies to fight infection, and these antibodies were less effective.

Nature | 4 min read

Reference: Science Translational Medicine paper

Features & opinion

To better understand how individuals might respond to certain treatments, researchers should work to develop the ‘immunome’: a comprehensive characterization of immune health across cells, tissues, organs and molecular interactions, argues a group of medical researchers. To start, scientists should identify key measures that could be used to flag any immune features that are weakened or declining. “If scientists can work out which measurements matter, validate them across diverse populations and establish when acting on them improves disease outcomes, immune health could become a routine dimension of medicine,” the group writes.

Nature | 11 min read

Ecologist Sage Raymond, who has previously been homeless, studies the interactions between urban wildlife and people living unsheltered. On a draft of her previous work, a reviewer commented that she and her colleagues seemed “naive about homelessness”. “That assumption shook me: it suggested someone with my history did not belong in academia,” Raymond writes. Her past has equipped her with skills that enable her research, but “many of the life experiences that bring diversity to science are invisible,” which leaves room for harmful assumptions, she writes.

Science | 5 min read

Today I’m pondering life’s important questions, such as: which animals could I beat in a running race? The answer is more complicated than you might think, say researchers. Many creatures have a higher top speed than the average person, but accelerate more slowly, researchers say. Distance is another factor, as speedy animals might not have the endurance to reach the finish line.

Unfortunately, I lack both speed and endurance, so my chances of a win are generally slim.

Let me know which animals you think you could best, along with any feedback on this newsletter, at briefing@nature.com.

Thanks for reading,

Jacob Smith, associate editor, Nature Briefing

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