2025-02-10
8 分钟Happy Monday, listeners, for Scientific American Science Quickly, I'm Rachel Feltman.
Let's kick off the week by catching up on some of the science news you may have missed.
First, a quick bird flu update.
If you're a regular listener, you already know that H5N1 bird flu has been circulating in US cattle for almost a year.
That's been thanks to a type called B3.13.
Now, a different variant of H5N1 that had been circulating in birds, known as the D1.1 genotype, has shown up in six herds in Nevada.
This suggests that our current outbreak involved more than one spillover event or an instance when a bird transmitted H5N1 to a cow.
We don't know when the D1.1 variant hopped over to cattle or how widely it's circulating.
People have previously been infected with D1.1, including two severe cases, and NPR reports that scientists have speculated that this genotype might be more dangerous to humans.
D1.1 was also responsible for the first US death from H5N1 flu when someone in Louisiana caught it from backyard flocks.
Let's move on to some other health news.
Last Monday, a study in Nature Medicine reported surprisingly high amounts of microplastic in human brain tissue.
Researchers looked at tissue samples from the brains, kidneys and livers of 52 cadavers and found that the brains contained seven to 30 times higher concentrations of microplastics than those other organs.
They also noted that the average concentration of microplastics in the brain rose by 50% from 2016 to 2024.
The scientists found that the average amount of microplastics in the brains of individuals who died last year was roughly equivalent to the weight of a plastic spoon spoon, according to the Washington Post.
We don't yet know exactly how microplastics impact our brains, but I'm gonna really go out on a limb and say the effects probably aren't great.
And speaking of brains, a new observational study suggests that people generally feel their best, at least mentally, in the morning.
Based on data from a multi year study that followed nearly 50,000 people, researchers publishing in BMJ Mental Health last Tuesday noted that in the morning, individuals tended to report higher levels of happiness, satisfaction with life and feelings that life was worthwhile, as well as lower amounts of negative feelings like anxiety and loneliness.
People typically felt their worst around midnight.
Unsurprisingly.