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Mysterious 'ghost population' of ancient humans discovered – CNN

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This “archaic ghost population” appears to have diverged from modern humans before Neanderthals split off from the family tree, according to the research published by the “Science Advances” journal.
The split appeared to have taken place between 360,000 and a million years ago, say the researchers from the University of California, Los Angeles. These ancient humans had babies with the ancestors of present-day Africans, much as Neanderthals reproduced with the ancestors of modern Europeans, wrote geneticists Arun Durvasula and Sriram Sankararaman.
DNA from this archaic population makes up between 2% and 19% of modern West Africans’ genetic ancestry, they said.
Neanderthal (left) and modern human skeleton.
Well-established research, the study says, has established the existence of Neanderthal DNA in modern European populations, and Denisovan DNA in Oceanic populations.
The UCLA researchers said that “while several studies have revealed contributions from deep lineages to the ancestry of present-day Africans, the nature of these contributions remains poorly understood.” This is in part because of sparse fossil records in Africa and the difficulty of obtaining ancient DNA.
The scientists from UCLA overcame these challenges to find the “ghost” of the hominin tribe by using computer modeling techniques on modern DNA.
They built “genome-wide maps of archaic ancestry” across four West African ethnic populations living in three countries: Nigeria, Sierra Leone and the Gambia.
There's a little cave man in all of us: Early human inbreeding There's a little cave man in all of us: Early human inbreeding
Researchers compared 405 genomes of West Africans with Neanderthal and Denisovan genomes, and worked out whether there had been interbreeding among an unknown hominin whose ancestors split off from the human family tree before Neanderthals. Data suggests this may have involved multiple populations.
Professor Joel D. Irish, a bioarchaeologist at Liverpool John Moores University, told CNN there were probably many different ancient human populations.
“I think at one time, there’d have been all sorts of populations, with genetics different enough to look a bit different,” he said.
“Everybody tends to mate with everybody. I think we’re going to find more and more of these ‘ghost’ populations coming up.”
After extracting the first genomes from the bones of Stone Age hominins, scientists discovered in 2010 that the early ancestors of Europeans, Asians and Americans reproduced with Neanderthals.
Last month, researchers from Princeton’s Lewis-Sigler Institute for Integrative Genomics said they also detected Neanderthal ancestry in Africans for the first time.
Their data indicated that a wave of modern humans left Africa for Europe about 200,000 years ago and interbred with Neanderthals, before migrating back to Africa.
It cast doubt on the widely held “out of Africa” theory of human migration, meaning that modern humans originated in Africa and dispersed to the rest of the world in a single wave between 60,000 and 80,000 years ago.

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Science News Roundup: British fossil hunters find bones of new dinosaur species, cousin to T.Rex; 'Secret' life of sharks and more – Devdiscourse

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Following is a summary of current science news briefs.

UC San Diego research lab to make environmentally friendly flip flops from algae

Researchers at the University of California, San Diego hope to make future beach visits both environmentally and fashion-friendly, with a new formula for biodegradable flip flops. Mike Burkart, professor of chemistry and biochemistry at the public research university in San Diego, California, has developed a polymer from algae, which decomposes naturally.

British fossil hunters find bones of new dinosaur species, cousin to T.Rex

Four bones found on a beach on the Isle of Wight, off England’s south coast, belong to a new species of theropod dinosaur, the group that includes Tyrannosaurus rex, researchers at the University of Southampton said on Wednesday. The new dinosaur, which has been named Vectaerovenator inopinatus, lived in the Cretaceous period 115 million years ago and was estimated to have been up to four metres long, the palaeontologists said.

Mystery of the dimming of massive star Betelgeuse explained

Astronomers have determined the cause of the dramatic dimming observed last year and earlier this year of one of the brightest stars in the night sky, a colossus called Betelgeuse that appears to be on its way toward a violent death. Based on Hubble Space Telescope observations, scientists said they believe Betelgeuse ejected a huge hot, dense cloud of material into space that cooled to form dust, shielding the star’s light and making it appear dimmer from the perspective of viewers on Earth.

‘Secret’ life of sharks: Study reveals their surprising social networks

Sharks have more complex social lives than previously known, as shown by a study finding that gray reef sharks in the Pacific Ocean cultivate surprising social networks with one another and develop bonds that can endure for years. The research focused on the social behavior of 41 reef sharks around the Palmyra Atoll, about 1,000 miles (1,600 km) southwest of Hawaii, using acoustic transmitters to track them and camera tags to gain greater clarity into their interactions.

Chemical signal for locust swarming identified in step toward curbing plagues

Scientists have identified a chemical compound released by locusts that causes them to swarm, opening the door to possible new ways to prevent these insects from devouring crops vital to human sustenance as they have for millennia. Researchers said on Wednesday they identified the pheromone – a chemical produced by an animal that affects the behavior of others of its own species – in the world’s most widespread locust species, the migratory locust, or Locusta migratoria.

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Perseid Meteor Shower is Expected to Peak on August 11 and 12, Here’s How You Can Watch This Astrono … – Gizmo Posts 24

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Though 2020 hasn’t been off the best of starts, we’ve still had a thing or two to cherish in these past few months. Apart from the pandemic, 2020 has been a year of several astronomical events. Right from January 2020, we have witnessed several major as well as minor astronomy events directly from our terrace or balcony. And after the last meteor shower in July 2020, it looks like we have another meteor shower to look for in August 2020.

It’s August, and its time for the best meteor showers of the year- the Perseid. The Perseid meteor is deemed as the best meteor shower to be observed. This meteor shower is caused by the comet ‘Swift-Tuttle,’ which was discovered in 1862. The Perseid meteor shower is famous for producing a large number of bright meteors. Actually, this meteor shower runs from July 17 to August 24 every year. However, the maximum show of Perseid Meteors occurs on 11th, 12th, and 13th August and is visible from both hemispheres.

Perseid Meteor Shower is Expected to Peak on August 11 and 12, Here’s How You Can Watch This Astronomy Event!

Though the Perseid meteor shower is visible from both hemispheres, it has the best view from the Northern hemisphere. The Perseid meteor shower tends to lose its intensity while being viewed from the Southern Hemisphere. One can see up to 100 meteors in an hour during the Perseid Meteor Shower.

The moon phase of 41.9% could interfere in the view. However, it is still a bright enough meteor shower allowing one to see up to 60 meteors in an hour. The Perseid Meteor shower will be best viewed from a dark location after midnight. Meteors will radiate from the constellation Perseus but can appear anywhere in the sky.

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'Canary in the coal mine': Greenland ice has shrunk beyond return, study finds – The Globe and Mail

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This early Friday, Aug. 16, 2019 file photo shows an aerial view of large Icebergs floating as the sun rises near Kulusuk, Greenland.

Felipe Dana/The Associated Press

Greenland’s ice sheet may have shrunk past the point of return, with the ice likely to melt away no matter how quickly the world reduces climate-warming emissions, new research suggests.

Scientists studied data on 234 glaciers across the Arctic territory spanning 34 years through 2018 and found that annual snowfall was no longer enough to replenish glaciers of the snow and ice being lost to summertime melting.

That melting is already causing global seas to rise about a millimetre on average per year. If all of Greenland’s ice goes, the water released would push sea levels up by an average of 6 meters – enough to swamp many coastal cities around the world. This process, however, would take decades.

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“Greenland is going to be the canary in the coal mine, and the canary is already pretty much dead at this point,” said glaciologist Ian Howat at Ohio State University. He and his colleagues published the study Thursday in the Nature Communications Earth & Environment journal.

The Arctic has been warming at least twice as fast as the rest of the world for the last 30 years, an observation referred to as Arctic amplification. The polar sea ice hit its lowest extent for July in 40 years.

The Arctic thaw has brought more water to the region, opening up routes for shipping traffic, as well as increased interest in extracting fossil fuels and other natural resources.

Greenland is strategically important for the U.S. military and its ballistic missile early warning system, as the shortest route from Europe to North America goes via the Arctic island.

Last year, President Donald Trump offered to buy Greenland, an autonomous Danish territory. But Denmark, a U.S. ally, rebuffed the offer. Then last month, the U.S. reopened a consulate in the territory’s capital of Nuuk, and Denmark reportedly said last week it was appointing an intermediary between Nuuk and Copenhagen some 3,500 kilometres away.

Scientists, however, have long worried about Greenland’s fate, given the amount of water locked into the ice.

The new study suggests the territory’s ice sheet will now gain mass only once every 100 years – a grim indicator of how difficult it is to regrow glaciers once they hemorrhage ice.

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In studying satellite images of the glaciers, the researchers noted that the glaciers had a 50% chance of regaining mass before 2000, with the odds declining since.

“We are still draining more ice now than what was gained through snow accumulation in ‘good’ years,” said lead author Michalea King, a glaciologist at Ohio State University.

The sobering findings should spur governments to prepare for sea-level rise, King said.

“Things that happen in the polar regions don’t stay in the polar region,” she said.

Still, the world can still bring down emissions to slow climate change, scientists said. Even if Greenland can’t regain the icy bulk that covered its 2 million square kilometres, containing the global temperature rise can slow the rate of ice loss.

“When we think about climate action, we’re not talking about building back the Greenland ice sheet,” said Twila Moon, a glaciologist at the National Snow and Ice Data Center who was not involved in the study. “We’re talking about how quickly rapid sea-level rise comes to our communities, our infrastructure, our homes, our military bases.”

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