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Monday, June 25, 2018

Science in 140 character: Chew on that

Harvard University professor Daniel Lieberman spent an afternoon chewing different cuts of raw goat meat.

Written by Jamie Mullick | Published: March 13, 2016 12:34:51 am

David Brin, astrophysicist

Harvard University professor Daniel Lieberman spent an afternoon chewing different cuts of raw goat meat. It wasn’t because he liked his steak extremely rare, but because he wanted to see if he could fill the nearly 2 million gap in the existence of the Homo sapien where it was consuming meat, but did not have the know-how to cook it yet. “You put it in your mouth and you chew and you chew and you chew and you chew, and nothing happens… It’s almost like a piece of chewing gum,” he tells LA Times in an article tweeted by astrophysicist David Brin. Modern human teeth, unlike the teeth of lions and wolves, he deduced, were not meant to break chunks of raw meat into pieces small enough to be swallowed. So how were we consuming meat for those 2 million years? In his study published in Nature magazine, Lieberman says that we could only do it because when humans shifted to a carnivorous diet, they started using stone tools. He says our ancestors used these tools to break the meat into tiny pieces and then our molars would crush them into pieces tiny enough to be swallowed. “We didn’t just start eating meat,” Lieberman said. “We had to invent some technology to be able to do it.”
Stressing over hair

Bethany Brookshire, Biologist
Have you been stressed about pulling out fistfuls of hair from your head in the shower lately? That stress may further increase your hair loss, according to an article tweeted by biologist Bethany Brookshire. Stress, according to the article by Julie Beck in The Atlantic, is thought to prematurely kick out hair that is still growing (otherwise we only lose hair that have stopped growing). A study done on rhesus macaque monkeys found that monkeys with more cortisol (a stress hormone) were more susceptible to hair loss. “Because there’s a delay between when a hair stops growing and when it falls out, there’s likewise a delay between a stressful event (which can be physical, like surgery or trauma, or emotional, like a divorce or loss of a job) and when hair loss might occur,” the article says. In humans, this delay is usually three months, which is the cycle period for our hair growth. Which means, that the increase in hair loss you saw in the shower today was likely caused by stress three months ago. This phenomenon can be easily traced after women give birth. Usually three months after they give birth, women complain of large amounts of hair loss, the article claims.

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