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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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Layered hybrid fibers could be used to build anti-viral masks, researchers say

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Oct. 14 (UPI) — Hybrid polymer fibers, featuring layers with different qualities, can be used for an array of biomedical applications, according to a new study in the journal Applied Physics Reviews.

Instead of searching for a single material that meets all the requirements of biomedical processes like tissue scaffolding, drug delivery and cardiac patching, authors of the new study suggest medical researchers utilize core-sheath polymer fibers — hybrid fibers featuring a strong core surrounded by a biologically applicable sheath layer.

“You want strength, but you also want bioactivity,” study co-author Mohan Edirisinghe said in a news release.

“So, if you align them in a core-sheath polymer, you have the strength of the core material, but the functionality comes from a bioactive polymer or ingredient that is in the sheath. That is a big advantage,” said Edirisinghe, a material scientist at University College London.

Because researchers can select from an array of materials to create the core-sheath fibers, the layered fibers could be used to meet a variety of biomedical applications, including the creation of antiviral mask materials.

“If you want to make a fibrous mask from a textile, you really need to have the strength, because you’re going to wash it and use it,” Edirisinghe said. “But on the other hand, you need an active material.”

Researchers suggest virus-fighting drugs or proteins could even be embedded in the fiber’s sheath layer during the manufacturing process.

Scientists have already augmented several fiber fabrication processes to create prototype core-sheath fibers.

One of the most promising methods involves embedding a vessel with a reservoir of the core material inside another vessel with a reservoir of sheath material. The reservoirs are released simultaneously through the vessel orifices, creating a bi-layered core-sheath fiber.

“This is just the tip of the iceberg, because this is just two reservoirs with two materials, which become the sheath and core layers of the fibers, but you can extend this to three or four,” Edirisinghe said. “In each layer, you can have a different drug that satisfies a different purpose.”



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Wolves can bond with their human handlers, but still unfit as pets

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Oct. 14 (UPI) — Wild wolves aren’t easy tame or train, but when they’re raised by humans and intensively socialized, new research suggests adult wolves can develop individualized social bonds with their human handlers.

Scientists suspect the last shared ancestor between the dog and grey wolf was a highly social animal, and that this sociality played an important role in the dog’s ultimate domestication. However, researchers know very little about evolutionary origins of dog-human attachment.

“Attachment is a so-called behavior-complex, what has several manifestations. For instance, dogs seek protection from their owners in threat or they are calmer in new situations when their owner is present, but they show signs of stress in their absence,” Rita Lenkei said in a news release.

“We were wondering whether intensively socialized adult wolves show at least some features of the attachment behavior toward their handlers,” said Lenkei, , researcher at the Biological Institute at Eötvös Loránd University in Budapest.

To gain a better understanding of what the first human-dog relationships might have looked like, researchers in Hungary observed hand-raised wolves and family dogs in a separation test.

As researchers detailed in their paper, published Wednesday in the journal Scientific Reports, the dogs and wolves behaved remarkably similar during the test.

“When their handler — or owner in case of the dogs — was present they were calmer, they spent their time exploring their vicinity and sniffing around,” study co-author Tamás Faragó, ethologist at Eötvös Loránd University. “But when they were left by their handler, they became stressed, whined and pulled the leash towards her hiding place. However, when the stranger disappeared these behaviors barely appeared.”

Genomic analysis has previously shown that dogs and wolves are very similar, genetically. The small genetic differences between dogs and wolves may explain why dogs in the test exhibited more interest toward humans, regardless of their familiarity with the individual.

Though previous studies have shown wolf puppies fail to develop attachment toward their human caregivers, the latest research suggests wolf-human bonding is real. Though the wolves in the latest tests were raised by humans, the human handlers were not the same caretakers that raised the wolf puppies.

Scientists estimate wolves’ ability to live and socialize within a multi-unit family allowed them to integrate themselves into human groups.

“It is important to emphasize the hand-rearing and the intensive socialization of our wolf subjects,” Lenkei said. “Without this process they would never show these behaviors towards humans.”

“Contrary to them, as a result of genetic changes, dogs are able to form attachment easily from their puppyhood and they can develop it thorough their whole life,” Lenkei said. “Thus, we must keep in mind that though during our test they showed similar behavior, we are talking about separate species and the dog is not just a tame wolf, while the wolf will never become a pet.”



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Ancient trash heaps in Israel show waste management changes among settlements

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Oct. 14 (UPI) — The contents of rural trash heaps outside several ancient Negev settlements suggest farmers during the Roman Imperial Period and Late Antiquity, between the 1st and 10th centuries AD, used livestock dung for fertilizer and as a main fuel source.

For the study, published Wednesday in the journal PLOS One, researchers analyzed trash mounds outside of Shivta, Elusa and Nessana, agrarian settlements that flourished during the Late Byzantine and Early Islamic periods, from the 4th through the 10th century AD.

By studying the varying concentrations of livestock dung, grass, wood and ash, researchers were able to gain new insights into shifting refuge management techniques and fuel usage among Negev’s early agrarian societies.

“Our findings provide much-needed new insight into community specific responses to social and economic transformations in the Negev during a pivotal time in its history — during the collapse of market-oriented agriculture and ruralization of the urban heartland near the end of the first millennium [AD],” researchers wrote in their paper.

Specifically, researchers found a consistent lack of raw livestock dung in all three trash mounds, suggesting sheep and goat dung fertilizer was vital to large-scale agriculture across the semi-arid region.

“Instead of being disposed of in trash dumps, dung would have been spread in agricultural plots,” researchers wrote.

The discovery of bits of burned livestock dung within the trash heaps outside Shivta and Elusa suggests livestock waste was also used as a fuel source. Woody plant material was scarce in the region. The practice suggests livestock herds were plentiful and household fuel needs did not interfere with field fertilization.

Not all of the livestock dung collected by Negev herders was shoveled into fields and furnaces.

“In sharp contrast to the sustainable use of dung for fuel, and reasonably for fertilizer as well, raw dung was dumped and burned atop the mound outside Early Islamic Nessana,” researchers wrote. “This is the first evidence of its kind from the Negev confirming the management of dung via controlled incineration.”

The sizable layers of scorched dung outside Nessana suggests that by the Early Islamic period, economic disruption had made the practice of dung recycling unnecessary.

“Several of the Arabic documents written after the fall of Byzantine hegemony speak of the difficulties Nessana residents had in paying rising taxes, particularly those levied against farmlands and produce,” researchers wrote.

With large-scale farming on the decline and trade networks crumbling, researchers suspect the market for commercial agricultural products collapses, as did the demands for dung as fuel and fertilizer.

“Nessana appears to have been transforming from an agricultural center into a more rural community persisting from smaller-scale domestic farming, semi-sedentary herding and wild game hunting,” researchers wrote.

The study’s authors said they hope their work will serve as reminder to archaeologists to look beyond buildings and city walls — that important insights into the ancient socioeconomic shifts can be gleaned from refuge.



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