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Mastodon migrations north offer clues about today's animal movements: study – Canada News – Castanet.net

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The migration of extinct mastodon herds to Yukon and Alaska during warm periods between ice ages could hold clues and warning signs for today’s animals moving north during a warming climate, says a new research paper.

The paper from Hamilton’s McMaster University, published Tuesday in the journal Nature Communications, says mastodon herds that migrated north during the warm periods were less genetically diverse, which made them more vulnerable to extinction.

Mastodons, similar to today’s elephants and extinct mammoths, roamed much of North America, including parts of Mexico. Mastodons went extinct about 11,000 years ago along with mammoths, large-toothed cats, giant beavers and western camels.

Emil Karpinski, a paleontologist at McMaster’s Ancient DNA Centre, said the report is the result of six years of research that examined the fossil bones and teeth of more than 30 different mastodons.

He said the research showed mastodons migrated north several times during periods between ice ages when the Earth warmed, but didn’t survive when ice ages returned.

“Mastodons were much more at home in these warmer, wooded wetland habitats with an abundance of shrubs and trees like spruce and pine for them to eat,” Karpinski told a panel discussion involving about a dozen mastodon experts.

“We wanted to see, which is kind of the end hope of all this research, if what we learn about these animals could be applied to present-day species,” he said.

“We’re observing very similar travels in species like moose, snowshoe hare, beavers, not just ones in the Arctic, but also various birds, fish and other species that are rapidly moving northward in response to climate warming.”

Karpinski said the research indicates the mastodon herds that migrated north were less genetically diverse and were more susceptible to extinction.

Grant Zazula, a Yukon government paleontologist and one of the report’s authors, said the research shows mastodon herds migrated north more than once with the same disastrous results.

He said the northern mastodons were decimated with the arrival of an ice age 250,000 years ago and were also wiped out by a second ice age about 100,000 years ago.

“Their populations would have peaked about 100,000 years ago and that’s when climates were essentially as warm as they are today and the environment looked very similar to today’s environment,” he said.

Zazula said mastodons were not equipped to survive the colder climates of the ice ages.

“What this is showing us is those populations kind of at the frontier of migrations and range extensions really lack genetic diversity,” he said. “It doesn’t take very much to wipe them out. It could be a change in climate. It could be hunting. It could be disease.”

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Australian stinging tree could pave way for novel painkillers – News-Medical.Net

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Australia is well known for having many of the world’s most venomous creatures, ranging from snakes, spiders, jellyfish, centipedes, fish, ticks, bees, and ants. 21 of the 25 most venomous snakes in the world are all from Australia. The country is also home to dangerous plants, like the Australian stinging tree.

Close up of the heart-shaped leaf of the most toxic of the Australian species of stinging trees Dendrocnide moroides, also known as the stinging brush, gympie stinger, moonlight plant among others. Image Credit: Victoria Tucholka / Shutterstock

Now, a team of researchers at the University of Queensland in Brisbane examined the toxins produced by two species of Australian stinging trees- the shrub-sized Gympie-Gympie (Dendrocnide moroides) and the giant Australian stinging tree (Dendrocnide excelsa).

Leaves of the fearsome giant stinging tree, Dendrocnide excelsa. Image Credit: Lakeview Images

Leaves of the fearsome giant stinging tree, Dendrocnide excelsa. Image Credit: Lakeview Images

The Gympie-Gympie stinging tree is one of the world’s most toxic plants and may cause excruciating long-lasting pain. From these plants, the researchers found a new family of toxins, which they called “gympietides” after the name of the tree. Usually, these trees are found in the Northern Rivers region of New South Wales and at the tip of the Cape York Peninsula.

“Our research on the venom of Australian stinging trees, found in the country’s northeast, shows these dangerous plants can inject unwary wanderers with chemicals much like those found in the stings of scorpions, spiders and cone snails,” the researchers said.

Long-lasting pain

The Australian stinging tree is covered with hollow needle-like hairs called trichomes, which are bolstered with silica. Like common nettles, the hairs contain toxins and substances, which can induce extreme pain.

The scientists reported that stinging trees produce extremely persistent and painful stings upon contact of their trichomes with mammalian skin. The pain typically lasts for several hours, and intermittent painful flares may occur for days and weeks.

“The Australian stinging tree species are particularly notorious for producing an excruciatingly painful sting, which unlike those of their European and North American relatives can cause symptoms that last for days or weeks,” Irina Vetter, associate professor at the UQ’s Institute for Molecular Bioscience, said.

“Like other stinging plants such as nettles, the giant stinging tree is covered in needle-like appendages called trichomes that are around five millimeters in length—the trichomes look like fine hairs, but act like hypodermic needles that inject toxins when they make contact with skin,” she added.

The team reported that the pain and stinging sensation might be tied to small-molecule neurotransmitters and inflammatory mediators. However, these compounds cannot explain the observed sensory effects.

In the study, published in the journal Science Advances, the team demonstrated that the venoms of the stinging trees contain unknown pain-inducing peptides.

Discovering gympietides

To arrive at the study findings, the team studied the stinging hairs from the giant Australian stinging tree, obtaining an extract from them. They separate them into their singular molecular contents. The substances produced extreme pain responses when they were tested in the laboratory.

The team discovered that the extract contains a small family of mini-proteins. Further, the team examined the genes that are found in the leaves of the Gympie-Gympie to find out which one could produce the toxin. From there, the team revealed molecules that can reproduce the pain response even when developed synthetically in the laboratory.

Gympietides contain an intricate three-dimensional structure maintained by links within the molecule that forms a knotted shape. Hence, the toxin is kept stable, which stays intact for a long time once it gets injected into the victim. The structure of the gympietides is similar to the toxins from the cone snail, scorpion, and spider venom, which affect ion channels in nerve cells that are known as mediators of pain.

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“The 3D structure of these gympietides is reminiscent of animal venom toxins targeting the same receptors, thus representing a remarkable case of inter-kingdom convergent evolution of animal and plant venoms,” the researchers wrote in the paper.

“Our work clarifies the molecular basis for the pain caused by these plants while enabling structure-activity and convergent evolution studies to define how ancestrally distinct peptides in venoms may elicit the same response at pain receptors,” they added.

The researchers hope that the toxins will provide new information on how pain-sensing nerves function, paving the way for the development of novel painkillers.

Journal reference:

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How to watch historic SpaceX rocket launch more Starlink satellites Friday – CNET

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The Falcon 9 rocket booster that sent NASA astronauts to the International Space Station in May is scheduled to get recycled again Friday, when SpaceX plans to send 60 more Starlink satellites to orbit atop its column of fire. 

Elon Musk’s trademark reusable rocket will be making its third flight when it lifts off from Florida’s Kennedy Space Center at 10:57 a.m. PT (1:57 p.m. ET). This specific unit sent astronauts Doug Hurley and Bob Behnken to orbit in May and then launched a South Korean satellite in July. So far, SpaceX has managed to launch and land the same rocket up to six times

The launch was originally scheduled for Thursday, but it got scrubbed and pushed back a day due to a “recovery issue.” It could be that SpaceX didn’t like the look of the weather in the Atlantic where the first stage and the fairing were set to be recovered. 

One half of the nose cone, or fairing, atop the rocket has also seen two previous flights, both of them earlier Starlink missions. 

This should be a fairly routine launch. It will be the 13th Starlink mission so far, and SpaceX is ultimately planning on dozens more as it grows its broadband mega-constellation.


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SpaceX Starship prototype takes first ‘hop’

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Following the launch and separation of the rocket’s second stage and payload, the first-stage booster will again return to Earth to land on a droneship in the Atlantic. 

SpaceX will stream the entire thing via the feed above, starting at about 10 minutes before launch.

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Scientists Find Efficient Way to Convert Carbon Dioxide into Ethylene | Chemistry, Materials Science – Sci-News.com

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A team of U.S. researchers has developed copper nanowires with rich surface steps to catalyze a chemical reaction that reduces carbon dioxide (CO2) emissions while generating ethylene (C2H4), an important chemical used to produce plastics, solvents, cosmetics and other important products globally.

Copper represents an effective catalyst in reducing carbon dioxide to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Choi et al report that copper nanowires with rich surface steps exhibit a remarkably high Faradaic efficiency for ethylene that can be maintained for over 200 hours. Image credit: Choi et al, doi: 10.1038/s41929-020-00504-x.

“The idea of using copper to catalyze this reaction has been around for a long time, but the key is to accelerate the rate so it is fast enough for industrial production,” said co-lead author Professor William Goddard III, a researcher in the Department of Applied Physics and Materials Science at Caltech.

“This study shows a solid path towards that mark, with the potential to transform ethylene production into a greener industry using carbon dioxide that would otherwise end up in the atmosphere.”

Using copper to kick start the carbon dioxide reduction into ethylene reaction has suffered two strikes against it.

First, the initial chemical reaction also produced hydrogen and methane — both undesirable in industrial production.

Second, previous attempts that resulted in ethylene production did not last long, with conversion efficiency tailing off as the system continued to run.

To overcome these two hurdles, Professor Goddard III and colleagues focused on the design of the copper nanowires with highly active steps — similar to a set of stairs arranged at atomic scale.

One intriguing finding of this collaborative study is that this step pattern across the nanowires’ surfaces remained stable under the reaction conditions, contrary to general belief that these high energy features would smooth out.

This is the key to both the system’s durability and selectivity in producing ethylene, instead of other end products.

The scientists demonstrated a carbon dioxide-to-ethylene conversion rate of greater than 70%, much more efficient than previous designs, which yielded at least 10% less under the same conditions.

The new system ran for 200 hours, with little change in conversion efficiency, a major advance for copper-based catalysts.

In addition, the comprehensive understanding of the structure-function relation illustrated a new perspective to design highly active and durable carbon dioxide reduction catalyst in action.

“We are at the brink of fossil fuel exhaustion, coupled with global climate change challenges,” said co-lead author Professor Yu Huang, a researcher in the Department of Materials Science and Engineering at the University of California, Los Angeles.

“Developing materials that can efficiently turn greenhouse gases into value-added fuels and chemical feedstocks is a critical step to mitigate global warming while turning away from extracting increasingly limited fossil fuels.”

“This integrated experiment and theoretical analysis presents a sustainable path towards carbon dioxide upcycling and utilization.”

The team’s paper was published in the journal Nature Catalysis.

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C. Choi et al. Highly active and stable stepped Cu surface for enhanced electrochemical CO2 reduction to C2H4. Nat Catal, published online September 7, 2020; doi: 10.1038/s41929-020-00504-x

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