Category: Articles

Archaeologists in China Discover the Oldest Stone Tools Outside Africa

Posted on by Zimmer

The New York Times, July 11, 2018

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The oldest stone tools outside Africa have been discovered in western China, scientists reported on Wednesday. Made by ancient members of the human lineage, called hominins, the chipped rocks are estimated to be as much as 2.1 million years old.

The find may add a new chapter to the story of hominin evolution, suggesting that some of these species left Africa far earlier than once believed and managed to travel over 8,000 miles east of their evolutionary birthplace.

The age of the Chinese tools suggests that the hominins who made them were neither tall nor big-brained. Instead, they may have been small bipedal apes, with brains about the size of a chimpanzee’s.

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How Long Can We Live? The Limit Hasn’t Been Reached, Study Finds

Posted on by Zimmer

The New York Times, June 28, 2019

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Since 1900, average life expectancy around the globe has more than doubled, thanks to better public health, sanitation and food supplies. But a new study of long-lived Italians indicates that we have yet to reach the upper bound of human longevity.

“If there’s a fixed biological limit, we are not close to it,” said Elisabetta Barbi, a demographer at the University of Rome. Dr. Barbi and her colleagues published their research Thursday in the journal Science.

The current record for the longest human life span was set 21 years ago, when Jeanne Calment, a Frenchwoman, died at the age of 122. No one has grown older since — as far as scientists know.

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A Crispr Conundrum: How Cells Fend Off Gene Editing

Posted on by Zimmer

The New York Times, June 12, 2018

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Human cells resist gene editing by turning on defenses against cancer, ceasing reproduction and sometimes dying, two teams of scientists have found.

The findings, reported in the journal Nature Medicine, at first appeared to cast doubt on the viability of the most widely used form of gene editing, known as Crispr-Cas9 or simply Crispr, sending the stocks of some biotech companies into decline on Monday.

Crispr Therapeutics fell by 13 percent shortly after the scientists’ announcement. Intellia Therapeutics dipped, too, as did Editas Medicine. All three are developing medical treatments based on Crispr.

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Hot Heads: Why Mammals Need R.E.M. Sleep

Posted on by Zimmer

The New York Times, June 7, 2018

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On a December evening in 1951, Eugene Aserinsky, a physiologist at the University of Chicago, placed electrodes on the scalp of his 8-year-old son, Armond, before putting him to bed. Then the scientist retired to another room to watch a row of pens quiver across a rolling sheet of paper, recording the electrical activity in the boy’s facial muscles.

Hours later, the pens started to swing wildly. To judge from the chart, it seemed as if Armond were awake, his eyes darting about the room. But when Aserinsky looked in on him, his son was fast asleep.

Aserinsky had discovered R.E.M. sleep.

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The Great Breakup: The First Arrivals to the Americas Split Into Two Groups

Posted on by Zimmer

The New York Times, May 31, 2018

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Early inhabitants of the Americas split into two populations over 13,000 years ago, according to a new study of ancient DNA, and remained separated for thousands of years.

Eventually, somewhere, the two groups met again and began commingling. Today, their descendants inhabit a vast region stretching from Mexico to the southern tip of South America.

The research, published on Thursday in the journal Science, paints a complex picture of human migrations through the Americas. When people arrived in the Western Hemisphere from Asia, they didn’t just move to new territories and settle down. 

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