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Neanderthals, Denisovans, humans genetically closer than polar bears, brown bears

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June 3 (UPI) — Several genomic studies have previously shown that Neanderthals, Denisovans and anatomically modern humans interbred. Now, new research suggests the trio of populations were so genetically similar that they most certainly produced healthy, fertile hybrids.

In a new study, published Wednesday in the journal Proceedings of the Royal Society B, scientists quantified the genetic differences between early humans and their closest relatives, Neanderthals and Denisovans.

The analysis showed the genetic distance values separating the three human species were smaller than the differences between modern animal species — like brown bears and polar bears — known to produce healthy hybrid offspring.

“Our desire to categorize the world into discrete boxes has led us to think of species as completely separate units,” Greger Larson, director of the Palaeogenomics and Bio-Archaeology Research Network at the University of Cambridge, said in a news release. “Biology does not care about these rigid definitions, and lots of species, even those that are far apart evolutionarily, swap genes all the time.”

“Our predictive metric allows for a quick and easy determination of how likely it is for any two species to produce fertile hybrid offspring,” Larson said. “This comparative measure suggests that humans and Neanderthals and Denisovans were able to produce live fertile young with ease.”

For the study, researchers looked at relationships between the fertility of modern animal hybrids and the genetic differences between the two hybridizing species. The analysis showed that species that were genetically more similar were more likely to produce fertile offspring.

The researchers also determined that there was a threshold for the fertility of hybrid offspring. When scientists used the results of their analysis to measure the relative genetic differences between Neanderthals, Denisovans and anatomically modern humans, they found the three human species more than surpassed the threshold.

Authors of the new study suggest their methodology can be used to determine the likelihood that any two species would produce healthy, fertile offspring. Such information could help zookeepers decide which animals to house together.

“Many decisions in conservation biology have been made on the basis that related organisms that produce hybrids in captivity should be prevented from doing so,” said Richard Benjamin Allen, co-first author of the study.

“Such an approach has not considered the significant role that hybridization has played in evolution in the wild, especially in populations under the threat of extinction,” Allen said. “Our study can be used to inform future conservation efforts of related species where hybridization or surrogacy programs could be viable alternatives.”



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‘Invisible’ words reveal common structure among famous stories

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Aug. 7 (UPI) — Storytelling requires a narrative arc, but the trajectory of a dramatic arc isn’t always obvious.

By tracing the abundance of “invisible” words — pronouns, articles and other short words — researchers were able to identify patterns shared by a diversity of stories, from Shakespeare to Spielberg, according to a study published Friday in Science Advances.

“Over the years, these ‘invisible’ words have been found to be related to a whole mess of psychological processes — how people use small words like articles and pronouns tell us about a person’s mental health, thinking style, their social status, and even how well they get along with other people,” study lead author Ryan Boyd told UPI.

“In many ways, it was a natural progression to look at what these words can tell us how the nature of stories,” said Boyd, a lecturer in behavioral analytics at the University of Leeds.

For the study, Boyd and his colleagues used a range of statistical techniques to analyze the abundance and distribution of invisible words in 40,000 fictional texts, including short stories, novels and movie scripts.

The analysis revealed a common structure — a so-called narrative curve — featuring three distinct phases.

During the “staging” phase, authors use prepositions and articles in greater abundance, peppering their prose with “a” and “the.” These words are more useful at the beginning, when authors must set the scene and provide the audience with basic information.

The middle phase is defined by plot progression, which is revealed by a greater abundance of auxiliary verbs, adverbs and pronouns — or interactional language. During this phase, “the house” from the staging phase becomes “her home” or “it.”

During the third phase, cognitive tension is ramped up as the narrative arc reaches a climax. As the author guides the reader or viewer through the process of conflict resolution, cognitive-processing words like “think,” “believe,” “understand” and “cause” begin to crop up in greater numbers.

Researchers found this three-phase narrative shape remained consistent, regardless of a stories length.

“A 25,000 word story has the same shape as a 250 word story,” said Boyd, lead author of the new study. “It seems, then, that we are able to do a good job of structuring our stories in an optimal way regardless of how much space we have to do it in.”

The researchers set up a website showing the shapes of staging, plot progression and cognitive tension in eight texts at The Arc of Narrative website.

The patterns left by invisible words proved both good and bad stories — tales spun by amateurs, as well as professionals — utilize similar structures.

“Our results confirm what people have long believed about stories,” Boyd said. “Like DNA, we knew about it long before we could actually see it and measure it. With these new methods, we are able to see and measure the ‘DNA’ of stories and understand them in more objective, scientific ways.”

According to Boyd, studying the patterns of stories can offer insights into cognitive processes unique to humans.

“What these story shapes seem to tell us is that we have, to some degree, evolved to process information in certain ways,” he said. “We need to understand the ‘who’ and ‘what’ in order to understand the ‘why’ of our everyday lives and the lives of others.”

The authors of the latest story are already mining text for other language patterns that might help researchers determine whether a story-teller is telling the truth, or perhaps reveal the secrets to a “good” story.



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Florida Current study confirms decline in strength of Gulf Stream

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Aug. 7 (UPI) — New research suggests the strength of the Florida Current, which forms the beginning of the Gulf Stream, has weakened considerably over the last century.

The findings, published Friday in the journal Nature Climate Change, corroborate the predictions of several models that suggest the Gulf Stream has slowed over the last several decades.

The Florida Current is a thermal ocean current that flows from west to east around the tip of Florida, joining the Gulf Stream off Florida’s east coast.

Scientists have been tracking the strength of the Florida Current since the early 1980s — not long enough to identify multi-decadal or centennial trends.

To better understand the current’s historical changes, Christopher Piecuch, researcher at the Woods Hole Oceanographic Institution in Massachusetts, decided to study the relationship between coastal sea level and the strength of near-shore currents.

While researchers have only been measuring the Florida Current for a few decades, scientists have been recording sea level data since the early 1900s. Piecuch was able to use the data to predict historic changes in the strength of near-shore currents.

“In the ocean, almost everything is connected,” Christopher Piecuch, sole author of the new study, said in a news release. “We can use those connections to look at things in the past or far from shore, giving us a more complete view of the ocean and how it changes across space and time.”

The statistical analysis performed by Piecuch showed the Florida Current and Gulf Stream are the weakest they’ve been during the last 110 years.

The findings are in agreement with ocean current models that suggest climate change has caused a slowdown of the Atlantic Meridional Overturning Circulation, of which the Gulf Stream is a part.

Piecuch said he hopes his research will help other scientists use coastal current data to study changes in bigger currents like the Gulf Stream.

“If we can monitor something over the horizon by making measurements from shore, then that’s a win for science and potentially for society,” he said.



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SpaceX, ULA win large government launch contracts

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Astronauts make round trip to space station from U.S. soil

NASA astronaut Douglas Hurley (C) waves to onlookers as he boards a plane at Naval Air Station Pensacola to return him and NASA astronaut Robert Behnken home to Houston a few hours after the duo landed in their SpaceX Crew Dragon Endeavour spacecraft off the coast of Pensacola, Fla,, on August 2, 2020. Photo by Bill Ingalls/NASA | License Photo



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