MI weekly selection #18


An abrupt and widespread climate shift in the Sahara 5,000 years ago

The Sahara Desert’s shift from lush grasslands to barren sands happened quickly and simultaneously across the entire region. Scientists say the brief African Humid Period began and ended suddenly, about 5,000 years ago.

MIT news

D. McGee, P.B. deMenocal, G. Winckler, J.-B. Stuut, L.I. Bradtmiller. The magnitude, timing and abruptness of changes in North African dust deposition over the last 20,000 years. Earth and Planetary Science Letters, in review.

Human gut bacteria may convert red meat to plaque

Bacteria in the human gut may convert nutrients in red meat into artery-clogging plaque, which can increase the risk of heart disease. Researchers found that the combination of L-carnitine, a nutrient found in red meat and dairy, and a common bacteria in the human gut speeds up the production of the plaque that ultimately clogs arteries.

Nature news

Robert A. Koeth et al. (2013) Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis Nature Medicine DOI: 10.1038/nm.3145

Primate’s warbling sounds give clues to early human speech

A strange sound made by a close relative of the baboon could be evidence of the origins of human speech. The study found that the gelada species makes sounds similar to human speech. In addition to the sound, which scientists have dubbed a “wobble,” the gelada can also make certain mouth movements, which researchers earlier speculated was related to speech.


Thore J. Bergman (2013) Speech-like vocalized lip-smacking in geladas Current Biology DOI: 10.1016/j.cub.2013.02.038

Japan hunter-gatherers may have used pottery for cooking
Japanese hunter-gatherers living during the end of the ice age may have turned to pottery as a source of cooking. The study details an analysis of charred material from various ceramic vessels and fragments that revealed some of the earliest evidence of cooking using pottery. Scientists also say they found traces of fatty acids belonging to creatures such as fish and other marine animals. The resulting substance would have only resulted after prolonged exposure to heat — suggesting long periods of cooking time.

Science Now

O.E. Craig (2013) Earliest evidence for the use of pottery Nature DOI: 10.1038/nature12109

Viking sailors used complex tools to navigate north to south
Vikings may have relied on complex sundials among other tools to determine latitude. The research looked at a Viking sundial discovered in Greenland that scientists believe may have been used to determine latitude, or north-south navigation. It seems they used much more sophisticated navigational instruments than we thought before.


Balázs Bernáth et al. (2013) An alternative interpretation of the Viking sundial artefact: an instrument to determine latitude and local noon Proceedings of the Royal Society A DOI: 10.1098/rspa.2013.0021

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