Hexbyte Glen Cove Evidence found of genetic evolution in Europeans over past several thousand years

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A team of researchers affiliated with several institutions in China has found evidence of natural selection based evolutionary changes to people living in Europe over the past two to three thousand years. In their paper published in the journal Nature Human Behavior, the group describes their comparative study of people living in the U.K. today, with those living across Europe over the past several thousand years.

Noting that few studies have been conducted with the goal of learning more about in people living in relatively , the researchers designed a study that was meant to learn more about how natural selection has impacted people living in Europe over the past several thousand years.

To that end, they obtained access to the U.K. Biobank and the data it holds, some of which is genetic. They also obtained similar data from other entities holding retrieved from the remains of people living in Europe over the past several thousand years. The team then selected 870 that have been identified as being associated with certain genes related to phenotype and compared those found in modern British people (most of whom have European backgrounds) with those found in people living across Europe over the past few thousand years.

In looking at the data, the researchers found evolution at work in 755 genes related to the traits they had selected over the past 2,000 to 3,000 years—and they included skin pigmentation, dietary traits and body measurements. All three traits were found to be under near constant selection pressure, leading to near constant changes to the genome.

They note that changes were expected due to the differences in exposure to ultraviolet light—the early migraters to Europe were known to have dark skin; over time, they became lighter. They also found changes related to consumption of vitamin D, heat regulation and body measurements. Such changes they note, were also likely due to changes in climate. The researchers also found that some expected changes had not come about—genetic factors associated with inflammatory bowel disease and anorexia nervosa, for example, had not changed much.

The research team acknowledges that their results are still preliminary as more detailed work is needed.



More information:
Weichen Song et al, A selection pressure landscape for 870 human polygenic traits, Nature Human Behaviour (2021). DOI: 10.1038/s41562-021-01231-4

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Evidence found of genetic evolution in Europeans over past several thousand years (2021, November 19)
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Hexbyte Glen Cove Groundwater in California’s Central Valley may be unable to recover from past and future droughts

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Hexbyte Glen Cove Natural enemy of invasive, berry-eating fly found in U.S.

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A parasitoid wasp, Ganaspis brasiliensis, is a native of South Korea, but has been found in the U.S. for the first time. The wasp is pictured here laying its eggs into a drosophila larva on a blueberry. Credit: Kent Daane, UC Riverside

A parasitoid wasp that is the natural enemy of a fly known as the spotted-wing drosophila could be a good friend to growers. Washington State University researchers recently confirmed the discovery of the potentially beneficial wasp in the United States for the first time. 

The drosophila flies cause major damage to several Washington crops, especially sweet cherries and berries. The wasp, which lays its eggs in the flies, could be a means of controlling their spread.

“This is really a positive step for the cherry and berry industries,” said Elizabeth Beers, a professor in WSU’s Department of Entomology. “Hopefully this speeds up the timeline to get biological control of the spotted-wing drosophila.”

Beers and her team found the parasitoid, called Ganaspis brasiliensis, this September, in a wild blackberry patch less than a mile from the Canadian border near Lynden, Washington. The tiny wasp was found in western British Columbia in 2019. Paul Abram, a Canadian colleague, asked Beers to watch for wasps crossing the border and provided tips on the best places to find them.

Another parasitoid of the drosophila pest, Leptopilina japonica, was also found in British Columbia in 2019 and in Washington state in 2020 by Chris Looney of the Washington State Department of Agriculture. But the new parasitoid which is native to South Korea has a major benefit: specificity.

“The Ganaspis is very host-specific; it really likes to attack spotted-wing drosophila larvae and generally doesn’t bother other species,” said Beers, who is based at WSU’s Tree Fruit Research and Extension Center in Wenatchee.

The invasive drosophila fly hurts fruit because it doesn’t just nibble on the outside—its larvae burrow down into a raspberry or cherry and ruin the entire thing. That’s where the parasitoid comes into play.

Leptopilina japonica, left, is another parasitoid of the invasive and damaging spotted-wing drosophila, right. Credit: Warren Wong, Agassiz R&D Center.

Beers said it’s just possible to see the tiny adult parasitoids flying around drosophila-infested fruit. The female Ganaspis then lay their eggs inside the drosophila larvae. The little parasitoid develops inside the drosophila larva, killing it in the process.

“It’s a bit like the movie Alien,” Beers said. “It’s unpleasant to think about in sci-fi movie terms, but really effective for killing spotted-wing drosophila.”

The Ganaspis parasitoids were recently approved by the U.S. Department of Agriculture Animal and Plant Health Inspection Service to be reared and distributed around the U.S. as a biocontrol.

To do that, an entomologist went to the native home of spotted-wing drosophila, found the Ganaspis, and brough back several samples. After significant research in quarantine, it was found to be safe to spread here to fight drosophila.

During that process, the Ganaspis found its own way to North America and is spreading without help. Once an invasive species is found living in a state, the USDA does not regulate it being distributed around that state, making the process easier.

“It’s kind of the best of both worlds,” Beers said. “It’s great that we have a lot of research showing that Ganaspis is very host-specific and safe to spread around. But there are also benefits to it being found here in nature.”

This is the third exotic species that Beers and her lab has found in the last few years. They found a parasitoid of the apple mealy bug, a pest for the apple industry, and the Samurai wasp.

“I never anticipated this, it’s not the main focus of our lab,” Beers said. “We’ve just kind of stumbled across them as part of our research on various pests.”



Citation:
Natural enemy of invasive, berry-eating fly found in U.S. (2021, November 18)
retrieved 18 November 2021
from https://phys.org/news/2021-11-natural-enemy-invasive-berry-eating.html

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Hexbyte Glen Cove NASA’s Perseverance captures challenging flight by Mars helicopter

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The flight model of NASA’s Ingenuity Mars Helicopter. Credits: NASA/JPL-Caltech

Video footage from NASA’s Perseverance Mars rover of the Ingenuity Mars Helicopter’s 13th flight on Sept. 4 provides the most detailed look yet of the rotorcraft in action.

Ingenuity is currently prepping for its 16th flight, scheduled to take place no earlier than Saturday, Nov. 20, but the 160.5-second Flight 13 stands out as one of Ingenuity’s most complicated. It involved flying into varied terrain within the “Séítah” geological feature and taking images of an outcrop from multiple angles for the rover team. Acquired from an altitude of 26 feet (8 meters), the images complement those collected during Flight 12, providing valuable insight for Perseverance scientists and rover drivers.

Captured by the ‘s two-camera Mastcam-Z, one video clip of Flight 13 shows a majority of the 4-pound (1.8-kilogram) rotorcraft’s flight profile. The other provides a closeup of takeoff and landing, which was acquired as part of a science observation intended to measure the dust plumes generated by the helicopter.

“The value of Mastcam-Z really shines through with these video clips,” said Justin Maki, deputy principal investigator for the Mastcam-Z instrument at NASA’s Jet Propulsion Laboratory in Southern California. “Even at 300 meters [328 yards] away, we get a magnificent closeup of takeoff and landing through Mastcam-Z’s ‘right eye.” And while the helicopter is little more than a speck in the wide view taken through the ‘left eye,” it gives viewers a good feel for the size of the environment that Ingenuity is exploring.”






Video footage from the Mastcam-Z instrument aboard NASA’s Perseverance Mars rover provides a big-picture perspective of the 13th flight of the agency’s Ingenuity Mars Helicopter, on Sept. 4, 2021. Credit: NASA/JPL-Caltech/ASU/MSSS

During takeoff, Ingenuity kicks up a small plume of dust that the right camera, or “eye,” captures moving to the right of the helicopter during ascent. After its initial climb to planned maximum altitude of 26 feet (8 meters), the helicopter performs a small pirouette to line up its color camera for scouting. Then Ingenuity pitches over, allowing the rotors’ thrust to begin moving it horizontally through the thin Martian air before moving offscreen. Later, the rotorcraft returns and lands in the vicinity of where it took off. The team targeted a different landing spot—about 39 feet (12 meters) from takeoff—to avoid a ripple of sand it landed on at the completion of Flight 12.

Though the view from Mastcam-Z’s left eye shows less of the helicopter and more of Mars than the right, the wide angle provides a glimpse of the unique way that the Ingenuity team programmed the flight to ensure success.

“We took off from the floor and flew over an elevated ridgeline before dipping into Séítah,” said Ingenuity Chief Pilot Håvard Grip of JPL. “Since the helicopter’s navigation filter prefers flat terrain, we programmed in a waypoint near the ridgeline, where the helicopter slows down and hovers for a moment. Our flight simulations indicated that this little ‘breather’ would help the helicopter keep track of its heading in spite of the significant terrain variations. It does the same on the way back. It’s awesome to actually get to see this occur, and it reinforces the accuracy of our modeling and our understanding of how to best operate Ingenuity.”






Video from the Mastcam-Z instrument aboard NASA’s Perseverance Mars rover captures a closeup view of the 13th flight of the agency’s Ingenuity Mars Helicopter, on Sept. 4, 2021. Credit: NASA/JPL-Caltech/ASU/MSSS

The wide-angle view also shows how Ingenuity maintains altitude during the flight. After an initial ascent to 26 feet (8 meters) altitude, the helicopter’s notes a change in elevation of the below as it heads northeast toward the ridgeline. Ingenuity automatically adjusts, climbing slightly as it approaches the ridge and then descending to remain 26 feet (8 meters) above the undulating surface. Once it flies to the right, out of view, Ingenuity collects 10 images of the rocky outcrop with its color camera before heading back into frame and returning to land in the targeted location.

After Flight 13, Ingenuity went quiet in October, along with NASA’s other Mars spacecraft during Mars solar conjunction, when the Red Planet and Earth are on opposite sides of the Sun, precluding most communications. Following conjunction, Ingenuity performed a short experimental flight test before undertaking Flight 15, which began the multi- journey back to the vicinity of “Wright Brothers Field,” its starting point back in April.



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NASA’s Perseverance captures challenging flight by Mars helicopter (2021, November 18)
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Hexbyte Glen Cove Exploding and weeping ceramics provide path to new shape-shifting material

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Creating shape-shifting materials is not an easy process. It involves a delicate tuning of the distances between atoms by compositional changes, so that the two phases fit together well. This diagram shows what happened when researchers implemented this recipe with one sample of ceramic material. Instead of improving the deformability of the ceramic, they observed that some specimens gradually fell apart into a pile of powder, a phenomenon they termed “weeping.” Credit: Gu, et al., University of Minnesota and Kiel University

An international team of researchers from the University of Minnesota Twin Cities and Kiel University in Germany have discovered a path that could lead to shape-shifting ceramic materials. This discovery could improve everything from medical devices to electronics.

The research is published in Nature.

Anyone who has ever dropped a coffee cup and watched it break into several pieces, knows that ceramics are brittle. Subject to the slightest deformation, they shatter. However, ceramics are used for more than just dishes and bathroom tiles, they are used in electronics because, depending on their composition, they may be semiconducting, superconducting, ferroelectric, or insulating. Ceramics are also non corrosive and used in making a wide variety of products, including , , , space shuttle tiles, chemical sensors, and skis.

On the other end of the materials spectrum are . They are some of the most deformable or reshapable materials known. Shape memory alloys rely on this tremendous deformability when functioning as medical stents, the backbone of a vibrant medical device industry both in the Twin Cities area and in Germany.

The origin of this shape-shifting behavior is a solid-to-solid phase transformation. Different from the process of crystallization–melting–recrystallization, crystalline solid–solid transitions take place solely in the solid state. By changing temperature (or pressure), a crystalline solid can be transformed into another crystalline solid without entering a .







This video shows a sample of ceramic material that has a composition tuned to have excellent compatibility between phases, but poor compatibility at grain boundaries. It explodes when passing through phase transformation. Credit: Jascha Rohmer, Kiel University

In this new research, the route to producing a reversible shape memory ceramic was anything but straightforward. The researchers first tried a recipe that has worked for the discovery of new metallic shape memory materials. That involves a delicate tuning of the distances between atoms by compositional changes, so that the two phases fit together well. They implemented this recipe, but, instead of improving the deformability of the ceramic, they observed that some specimens exploded when they passed through the phase transformation. Others gradually fell apart into a pile of powder, a phenomenon they termed “weeping.”

With yet another composition, they observed a reversible transformation, easily transforming back and forth between the phases, much like a shape memory material. The mathematical conditions under which reversible transformation occurs can be applied widely and provide a way forward toward the paradoxical shape-memory .

“We were quite amazed by our results. Shape-memory ceramics would be a completely new kind of functional material,” said Richard James, a co-author of the study and a Distinguished McKnight University Professor in the University of Minnesota’s Department of Aerospace Engineering Mechanics. “There is a great need for shape memory actuators that can function in high temperature or in corrosive environments. But what excites us most is the prospect of new ferroelectric ceramics. In these materials, the phase transformation can be used to generate electricity from small temperature differences.”







This video shows a sample that has a composition tuned to have excellent compatibility between phases, but poor compatibility at grain boundaries. It gradually falls apart at the grain boundaries on passing through phase transformation. A phenomenon the authors call “weeping.”. Credit: Jascha Rohmer, Kiel University

The team from Germany was responsible for the experimental part and the chemical and structural investigation at the nanoscale.

“For the explanation of our experimental discovery that, contrary to expectation, the ceramics are extremely incompatible and explode or decay, the collaboration with Richard James’ group at the University of Minnesota was very valuable,” says Eckhard Quandt, a co-author of the study and a professor in the Institute for Materials Science, at Kiel University. “The theory developed on this basis not only describes the behavior, but also shows the way to get to the desired compatible ceramics.”

James also highlighted the importance of the collaboration between the University of Minnesota and Kiel University.







This video shows a sample of ceramic material that transforms back and forth between the phases, much like a shape memory material. The mathematical conditions under which reversible transformation occurs can be applied widely and provide a way forward toward the paradoxical shape-memory ceramic. Credit: Jascha Rohmer, Kiel University

“Our collaboration with Eckhard Quandt’s group at Kiel University has been tremendously productive,” added James. “As in all such collaborations, there is sufficient overlap that we communicate well, but each group brings plenty of ideas and techniques that expand our collective ability to discover.”

In addition to James and Quandt, the research team included Lorenz Kienle from Kiel University Andriy Lotnyk from the Leibniz Institute of Surface Engineering, and graduate students Hanlin Gu, Jascha Romer, and Justin Jetter.



More information:
Hanlin Gu et al, Exploding and weeping ceramics, Nature (2021). DOI: 10.1038/s41586-021-03975-5

Citation:
Exploding and weeping ceramics provide path to new shape-shifting material (2021, November 17)
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Hexbyte Glen Cove Using virtual fluid for the description of interfacial effects in metallic materials

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Schematic representation of an imperfect metal on which ions and their smeared-out mirror charges are shown. Credit: University of Stuttgart / Alexander Schlaich

Liquids containing ions or polar molecules are ubiquitous in many applications needed for green technologies such as energy storage, electrochemistry or catalysis. When such liquids are brought to an interface such as an electrode—or even confined in a porous material—they exhibit unexpected behavior that goes beyond the effects already known. Recent experiments have shown that the properties of the employed material, which can be insulating or metallic, strongly influence the thermodynamic and dynamic behavior of these fluids.

To shed more light on these effects, physicists at the University of Stuttgart, Université Grenoble Alpes and Sorbonne Université Paris have developed a novel computer simulation strategy using a virtual fluid that allows the within any material to be taken into account while being computationally sufficiently efficient to study the properties of at such interfaces. The new method has now made it possible for the first time to study the wetting transition at the nanoscale, which depends on whether the ionic liquid encounters a material that has insulating or metallic properties. This breakthrough approach provides a new theoretical framework for predicting the unusual behavior of charged liquids, especially in contact with nanoporous metallic structures, and has direct applications in the fields of energy storage and environment.

Despite their key role in physics, chemistry and biology, the behavior of ionic or dipolar near surfaces—such as a porous material—remains puzzling in many respects. One of the greatest challenges in the theoretical description of such systems is the complexity of the electrostatic interactions. For example, an ion in a perfect metal produces an inverse counter-charge, which corresponds to the negative mirror image. In contrast, no such image charges are induced in a perfect insulator because there are no freely moving electrons. However, any real, i.e., non-idealized material has properties that lie exactly between the two previously mentioned asymptotes. Accordingly, the metallic or insulating nature of the material is expected to have a significant influence on the properties of the adjacent fluid. However, established theoretical approaches reach their limits here, since they assume either perfectly metallic or perfectly insulating materials. To date, there is a gap in the description when it comes to explaining the observed surface properties of real materials in which the mirror charges are sufficiently smeared out.

In their recent paper published in Nature Materials, Dr. Alexander Schlaich from the University of Stuttgart and the research team present a new atomic-scale simulation method that allows them to describe the of a liquid to a surface while explicitly considering the electron distribution in the metallic material.

While common methods consider surfaces made of an insulating material or a perfect metal, they have developed a method that mimics the effects of electrostatic shielding caused by any material between these two extremes. The essential point of this approach is to describe the Coulombic interactions in the metallic material by a “virtual” fluid composed of light and fast charged particles. These create electrostatic shielding by reorganizing in the presence of the fluid. This strategy is particularly easy to implement in any standard atomistic simulation environment and can be easily transferred. In particular, this approach allows the calculation of the capacitive behavior of realistic systems as used in energy storage applications.

As part of the SimTech cluster of excellence at the University of Stuttgart, Alexander Schlaich is using such simulations of porous, conductive electrode materials to optimize the efficiency of the next generation of supercapacitors, which can store enormous power density. The wetting behavior of aqueous salt solutions in realistic porous materials is also the focus of his contribution to the Stuttgart Collaborative Research Center 1313 “Interface-driven multi-field processes in porous media—flow, transport and deformation,” which also investigates precipitation and evaporation processes related to soil salinization. The developed methodology is thus relevant for a wide range of systems, as well as for further research at the University of Stuttgart.



More information:
Alexander Schlaich et al, Electronic screening using a virtual Thomas–Fermi fluid for predicting wetting and phase transitions of ionic liquids at metal surfaces, Nature Materials (2021). DOI: 10.1038/s41563-021-01121-0

Citation:
Using virtual fluid for the description of interfacial effects in metallic materials (2021, November 17)

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Hexbyte Glen Cove Twin of NASA’s Perseverance Mars rover begins terrain tests

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Updated with new features, the Earthly twin of NASA’s Perseverance Mars rover arrives at the Mars Yard garage at the agency’s Jet Propulsion Laboratory on Oct. 29, 2021. Credit: NASA/JPL-Caltech

On a recent day in November, the car-size rover rolled slowly forward, then stopped, perched on the threshold of a Martian landscape. But this rover, named OPTIMISM, wasn’t on the Red Planet. And the landscape was a boulder-strewn mock-up of the real Mars—the Mars Yard at NASA’s Jet Propulsion Laboratory in Southern California.

OPTIMISM, a twin of the Perseverance rover that is exploring Jezero Crater on Mars, will perform a crucial job in the weeks ahead: Navigating the Mars Yard’s slopes and hazards, drilling sample cores from boulders, and storing the samples in metal tubes—just like Perseverance is doing in its hunt for signs of ancient microbial life. Short for Operational Perseverance Twin for Integration of Mechanisms and Instruments Sent to Mars, OPTIMISM is more generically known as a vehicle system test bed, and the recently upgraded rover begins testing out new equipment for the first time this month.

The tests help ensure that OPTIMISM’s twin on Mars can safely execute the commands sent by controllers on Earth. They also could potentially reveal unexpected problems Perseverance might encounter.

“The size and shape of rocks in the visual field—will they turn into obstacles or not?” said Bryan Martin, the flight software and test beds manager at JPL. “We test a lot of that, figure out what kinds of things to avoid. What we have safely traversed around here has informed rover drivers in planning their traverses on Mars. We’ve done so much testing on the ground we can be confident in it. It works.”

About as long as a doubles tennis court and twice as wide, the Mars Yard has served as a testing ground for many a fully-engineered rover twin—from the engineering model of the very first, tiny Sojourner that landed on Mars in 1997 to the Spirit and Opportunity missions that began in 2004 to the Curiosity and Perseverance rovers exploring Mars today.

In each case, a rover double has scaled slopes, dodged obstacles, or helped rover planners puzzle out new paths on the simulated patch of Mars. OPTIMISM first rolled out into the Mars Yard in September 2020, when it conducted mobility tests.

But it recently received some key updates to match features available on Perseverance, including additional mobility software and the bulk of the exquisitely complex sample caching system. And while the team has already performed tests using the coring drill at the end of OPTIMISM’s robotic arm, they’ll be testing the newly installed Adaptive Caching Assembly for the first time in the Mars Yard. The assembly on Perseverance is responsible for storing rock and sediment samples. Some or all of these initial samples could be among those returned to Earth by a future mission.

“Now we can do it end-to-end in the test bed,” said the Vehicle System Test Bed systems engineering lead, Jose G. Trujillo-Rojas. “Drill into the rock, collect the core sample, and now we have the mechanism responsible to cache that sample in the cylinder.”

And if problems arise on Perseverance on Mars, OPTIMISM can be used as a platform to figure out what went wrong and also how to fix it.

Twin twins

On this November day, a heavy-duty vehicle transported OPTIMISM from a JPL test lab to the Mars Yard garage. Recently expanded, the structure also provides shelter to one of Curiosity’s Earthly counterparts: MAGGIE, or Mars Automated Giant Gizmo for Integrated Engineering. A second Curiosity double, a skeletal version called “Scarecrow” that lacks a computer brain, is housed in a separate shed in the Mars Yard.

MAGGIE would be joining OPTIMISM in the Mars Yard garage in the days ahead.

But, for now, the test-bed crew was focused on OPTIMISM. “Straight 5 meters forward: Ready?” Leann Bowen, a test bed engineer, called out from a computer console inside the garage.

“All right, bring her home, Leann,” Trujillo-Rojas said.

With a whine of electric motors, OPTIMISM crept forward on its six metal wheels, stopping right on the mark on the garage’s concrete floor as members of the team looked on in their white lab coats. Through a wide-open door ahead of the rover, the Mars Yard beckoned.

Drilling core samples from terrestrial rocks in the Mars Yard and sealing them in metal tubes is not as straightforward as it might sound. JPL’s Mars team provides a variety of rock types for OPTIMISM to drill through, since the exact nature of the rock Perseverance will encounter often can’t be known in advance. Terrain is a variable, too: One previous test with the robotic arm involved parking the rover on a slope, then instructing it to drill.

Engineering models of the Curiosity Mars rover (foreground) and the Perseverance Mars rover share space in the garage at JPL’s Mars Yard. Credit: NASA/JPL-Caltech

“There was a possibility that the rover might slip,” Trujillo-Rojas said. “We wanted to test that first here on Earth before sending instructions to the rover on Mars. That was scary, because you can imagine if you drill this way, and the rover slightly slipped back, the drill could have gotten stuck.”

OPTIMISM drilled the core successfully, suggesting Perseverance also could pull off on a slope if required.

Test drive

With longer drives in Perseverance’s near future, another job for the Earth-bound twin will involve presenting new challenges to the rover’s autonomous navigation system, or AutoNav. Perseverance uses a powerful computer to make 3D maps using rover images of the ahead, and uses those maps to plan its drive with minimal human assistance.

In Mars Yard tests, the twin rover might pause as it “thinks through” several possible choices—or even decides, unexpectedly, to avoid altogether and just go around.

“Seeing the rover autonomously move in the Mars Yard, you kind of get that sense of being connected to the rover on Mars,” he said. “It gives you that visual connection.”

Of course, OPTIMISM and its human team must contend with environmental factors very different from those encountered by Perseverance, which is built for freezing temperatures and intense radiation. Earth’s stronger gravity required OPTIMISM’s metal wheels to be thicker than its Martian counterpart’s. And its electronics sometimes must be cooled to avoid damage from Southern California’s summer temperatures—the opposite of the problem caused by deep cold on Mars.

“On Mars, we try to keep the rover warm,” Trujillo-Rojas said. “Here, we’re trying to keep it cool.”

Deer, bobcats, tarantulas, even occasional snakes, find their way into the Mars Yard. Wildfire in the region can fill the air with smoke. And testing and staffing schedules had to contend with COVID-19.

“We’ve been through a lot of challenges with this rover,” he said. “As soon as we were going to start building it, with hands-on integration, the pandemic happened. And then we had rains, and we got a lot of fire. We had to leave the lab—smoky!”

Now, a revamped OPTIMISM is ready to get back to work.

“It’s a big milestone for our team,” Trujillo-Rojas said.

More about the mission

A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.



More information:
For more about Perseverance, visit mars.nasa.gov/mars2020/ and nasa.gov/perseverance

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Hexbyte Glen Cove Inspired by art, researchers find the finger snap to have the highest acceleration the human body produces

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This comic depicts the Bhamla Lab research in an exciting and engaging way – all pointing back to curiosity-driven science and how it can impact scientific research. Credit: Lindsey Leigh for Georgia Tech

The snapping of a finger was first depicted in ancient Greek art around 300 B.C. Today, that same snap initiates evil forces for the villain Thanos in Marvel’s latest Avengers movie. Both media inspired a group of researchers from the Georgia Institute of Technology to study the physics of a finger snap and determine how friction plays a critical role.

Using an intermediate amount of , not too high and not too low, a snap of the finger produces the highest rotational accelerations observed in humans, even faster than the arm of a professional baseball pitcher. The results were published Nov. 17 in the Journal of the Royal Society Interface.

The research was led by an undergraduate student at Georgia Tech, Raghav Acharya, as well as doctoral student Elio Challita, Assistant Professor Saad Bhamla of the School of Chemical and Biomolecular Engineering, and Assistant Professor Mark Ilton of Harvey Mudd College in Claremont, California.

Their results might one day inform the design of prosthetics meant to imitate the wide-ranging capabilities of the human hand. Bhamla said the project is also a prime example of what he calls curiosity-driven science, where everyday occurrences and biological behaviors can serve as data sources for new discoveries.

“For the past few years, I’ve been fascinated with how we can snap our ,” Bhamla said. “It’s really an extraordinary physics puzzle right at our fingertips that hasn’t been investigated closely.”

In earlier work, Bhamla, Ilton, and other colleagues had developed a general framework for explaining the surprisingly powerful and ultrafast motions observed in living organisms. The framework seemed to naturally apply to the snap. It posits that organisms depend on the use of a spring and latching mechanism to store up energy, which they can then quickly release.







Slow motion finger snap with sound. Credit: Georgia Tech

Acharya and Bhamla felt a particular push to apply this framework to a finger snap after seeing the movie Avengers: Infinity War, released in April 2018 and produced by Marvel Studios. In it, Thanos, a villainous character, seeks to obtain six special stones and place them into his metal gauntlet. After collecting them all, he snaps his fingers and triggers universe-wide consequences.

But would it be possible to snap at all while wearing an armor gauntlet, the researchers asked? In the case of a finger snap, they suspected that skin friction played a more important role compared to other spring and latch systems. With the frictional properties of a metal gauntlet, they imagined it might be impossible.

Using high-speed imaging, automated image processing, and dynamic force sensors, the researchers analyzed a variety of finger snaps. They explored the role of friction by covering fingers with different materials, including metallic thimbles to simulate the effects of trying to snap while wearing a metallic gauntlet, much like Thanos.

For an ordinary snap with bare fingers, the researchers measured maximal rotational velocities of 7,800 degrees per second and rotational accelerations of 1.6 million degrees per second squared. The rotational velocity is less than that measured for the fastest rotational motions observed in humans, which come from the arms of professional baseball players during the act of pitching. However, the snap acceleration is the fastest human angular acceleration yet measured, almost three times faster than the rotational acceleration of a professional baseball pitcher’s arm.

“When I first saw the data, I jumped out of my chair,” said Bhamla, who studies ultrafast motions in a variety of living systems, from single cells to insects. “The finger snap occurs in only seven milliseconds, more than twenty times faster than the blink of an eye, which takes more than 150 milliseconds.”

When the fingertips of the subjects were covered with metal thimbles, their maximal rotational velocities decreased dramatically, confirming the researchers’ intuitions.

Saad Bhamla snapping. Credit: Georgia Tech

“Our results suggest that Thanos could not have snapped because of his metal armored fingers,” said Acharya, first author of the study. “So, it’s probably the Hollywood special effects, rather than actual physics, at play! Sorry for the spoiler.”

They explained this decrease by considering the diminished contact area that exists between thimble-covered fingers.

“The compression of the skin makes the system a little bit more fault tolerant,” said Challita, a coauthor on the work. “Reducing both the compressibility and friction of the skin make it a lot harder to build up enough force in your fingers to actually snap.”

Surprisingly, increasing the friction of the fingertips with rubber coverings also reduced speed and acceleration. The researchers concluded that a Goldilocks zone of friction was necessary—too little friction and not enough energy was stored to power the snap, and too much friction led to energy dissipation as the fingers took longer to slide past each other, wasting the stored energy into heat.

The researchers experimented with a variety of mathematical models of the snapping process to explain their observations. They found that a model including a spring and a soft friction contact-latch could reproduce the qualitative features of their results.

“We included soft frictional contact into our mathematical model, and the results reinforced the central role played by friction in achieving ultrafast motions,” Ilton said. “This model can now help us understand how other animals such as termites and ants snap their mandibles, as well as rationally bioinspired actuators for engineering applications.”

Ancient Greek vase depicting a finger snap. Credit: Wikicommons

John Long, a program director in the National Science Foundation’s Division of Integrative Organismal Systems, oversees research in the Physiological Mechanisms and Biomechanics Program, which currently funds Bhamla’s investigations into ultrafast behaviors in animals.

“This research is a great example of what we can learn with clever experiments and insightful computational modeling,” he said. “By showing that varying degrees of friction between the fingers alters the elastic performance of a snap, these scientists have opened the door to discovering the principles operating in other organisms, and to putting this mechanism to work in engineered systems such as bioinspired robots.”

John Long, program director in the Directorate for Biological Sciences at the National Science Foundation, oversees research in the Physiological Mechanisms and Biomechanics Program, which currently funds Bhamla’s investigations into ultrafast behaviors in animals.

“The research of Dr. Bhamla and his colleagues is a great example of what we can learn with clever experiments and insightful computational modeling,” he said. “By showing that varying degrees of friction between the fingers alters the elastic performance of the snap, they’ve opened the door for discovering these principles operating in other organisms and for putting this soft, sophisticated, and adjustable mechanism to work in engineered systems such as bioinspired robots.”

The researchers believe that the results open a variety of opportunities for future study, including understanding why humans snap at all, and if humans are the only primates to have evolved this physical ability.

“Based on ancient Greek art from 300 B.C., humans may very well have been snapping their fingers for hundreds of thousands of years before that, yet we are only now beginning to scientifically study it,” Bhamla said. “This is the only scientific project in my lab in which we could snap our fingers and get data.”



More information:
The ultrafast snap of a finger is mediated by skin friction, Journal of the Royal Society Interface (2021). DOI: 10.1098/rsif.2021.0672. rsif.royalsocietypublishing.or … .1098/rsif.2021.0672

Citation:
Inspired by art, researchers find the finger snap to have the highest acceleration the human body produces (2021, November 16)
retrieved 16 November 2021
from https://phys.org/news/2021-11-art-finger-snap-highest-human.html

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Hexbyte Glen Cove Machine learning IDs mammal species with the potential to spread SARS-CoV-2

Hexbyte Glen Cove

Credit: Pixabay/CC0 Public Domain

Back and forth transmission of SARS-CoV-2 between people and other mammals increases the risk of new variants and threatens efforts to control COVID-19. A new study, published today in Proceedings of the Royal Society B, used a novel modelling approach to predict the zoonotic capacity of 5,400 mammal species, extending predictive capacity by an order of magnitude. Of the high risk species flagged, many live near people and in COVID-19 hotspots.

A major bottleneck to predicting high-risk is limited data on ACE2, the that SARS-CoV-2 binds to in animals. ACE2 allows SARS-CoV-2 to enter host cells, and is found in all major vertebrate groups. It is likely that all vertebrates have ACE2 receptors, but sequences were only available for 326 .

To overcome this obstacle, the team developed a that combined data on the biological traits of 5,400 mammal species with available data on ACE2. The goal: to identify mammal species with high ‘zoonotic capacity’ – the ability to become infected with SARS-CoV-2 and transmit it to other animals and people. The method they developed could help extend predictive capacity for disease systems beyond COVID-19.

Co-lead author Ilya Fischhoff, a postdoctoral associate at Cary Institute of Ecosystem Studies, comments, “SARS-CoV-2, the virus that causes COVID-19, originated in an animal before making the jump to people. Now, people have caused spillback infections in a variety of mammals, including those kept in farms, zoos, and even our homes. Knowing which mammals are capable of re-infecting us is vital to preventing spillback infections and dangerous new variants.”

When a virus passes from people to animals and back to people it is called secondary spillover. This phenomenon can accelerate new variants establishing in humans that are more virulent and less responsive to vaccines. Secondary spillover of SARS-CoV-2 has already been reported among farmed mink in Denmark and the Netherlands, where it has led to at least one new SARS-CoV-2 variant.

Senior author and Cary Institute disease ecologist, Barbara Han, says, “Secondary spillover allows SARS-CoV-2 established in new hosts to transmit potentially more infectious strains to people. Identifying mammal species that are efficient at transmitting SARS-CoV-2 is an important step in guiding surveillance and preventing the virus from continually circulating between people and other animals, making disease control even more costly and difficult.”

Binding to ACE2 receptors is not always enough to facilitate SARS-CoV-2 viral replication, shedding, and onward transmission. The team trained their models on a conservative binding strength threshold informed by published ACE2 amino acid sequences of vertebrates, analyzed using a software tool called HADDOCK (High Ambiguity Driven protein-protein DOCKing). This software scored each species on predicted binding strength; stronger binding likely promotes successful infection and viral shedding.

Co-lead author and Cary Institute postdoctoral analyst, Adrian Castellanos, says, “The ACE2 receptor performs important functions and is common among vertebrates. It’s likely that it evolved in animals alongside other ecological and life history traits. By comparing biological traits of species known to have the ACE2 receptor with traits of other mammal species, we can make predictions about their capacity to transmit SARS-CoV-2.”

This combined modeling approach predicted zoonotic capacity of mammal species known to transmit with 72% accuracy and identified numerous additional mammal species with the potential to transmit SARS-CoV-2. Predictions matched observed results for white-tailed deer, mink, raccoon dogs, snow leopard, and others. The model found that the riskiest mammal species were often those that live in disturbed landscapes and in close proximity to people—including domestic animals, livestock, and animals that are traded and hunted.

The top 10% of high-risk species spanned 13 orders. Primates were predicted to have the highest zoonotic capacity and strongest viral binding among mammal groups. Water buffalo, bred for dairy and farming, had the highest risk among livestock. The model also predicted high zoonotic potential among live-traded mammals, including macaques, Asiatic black bears, jaguars, and pangolins—highlighting the risks posed by live markets and wildlife trade.

SARS-CoV-2 also presents challenges for wildlife conservation. Infection has already been confirmed in Western lowland gorillas. For high-risk charismatic species like mountain gorillas, spillback infection could occur through ecotourism. Grizzly bears, polar bears, and wolves, all in the 90th percentile for predicted zoonotic capacity, are frequently handled by biologists for research and management.

Han explains, “Our model is the only one that has been able to make risk predictions across nearly all mammal species. Every time we hear about a new species being found SARS-CoV-2 positive, we revisit our list and find they are ranked high. Snow leopards had a risk score around the 80th percentile. We now know they are one of the wildlife species that could die from COVID-19.”

People working in close proximity with high-risk mammals should take extra precautions to prevent SARS-CoV-2 spread. This includes prioritizing vaccinations among veterinarians, zookeepers, livestock handlers, and other people in regular contact with . Findings can also guide targeted vaccination strategies for at-risk mammals.

Han concludes, “We found that the riskiest species are often the ones that live alongside us. Targeting these species for additional lab validation and field surveillance is critical. We should also explore underutilized data sources like natural history collections, to fill data gaps about animal and pathogen traits. More efficient iteration between computational predictions, lab analysis, and animal surveillance will help us better understand what enables spillover, spillback, and secondary transmission—insight that is needed to guide zoonotic pandemic response now and in the future.”



More information:
Predicting the zoonotic capacity of mammals to transmit SARS-CoV-2, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2021.1651. rspb.royalsocietypublishing.or … .1098/rspb.2021.1651

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Hexbyte Glen Cove Life on Mars search could be misled by false fossils, study says

Hexbyte Glen Cove

Composite image showing some of the types of fossil-like specimens created by chemical reactions that could be found on Mars. Credit: Sean McMahon, Julie Cosmidis and Joti Rouillard

Mars explorers searching for signs of ancient life could be fooled by fossil-like specimens created by chemical processes, research suggests.

Rocks on Mars may contain numerous types of non-biological deposits that look similar to the kinds of fossils likely to be found if the planet ever supported life, a study says.

Telling these false fossils apart from what could be evidence of ancient life on the surface of Mars—which was temporarily habitable four billion years ago—is key to the success of current and future missions, researchers say.

Astrobiologists from the Universities of Edinburgh and Oxford reviewed evidence of all known processes that could have created lifelike deposits in rocks on Mars.

They identified dozens of processes—with many more likely still undiscovered—that can produce structures that mimic those of microscopic, simple lifeforms that may once have existed on Mars.

Among the lifelike specimens these processes can create are deposits that look like and carbon-based molecules that closely resemble the building blocks of all known life.

Because signs of life can be so closely mimicked by non-living processes, the origins of any fossil-like specimens found on Mars are likely to be very ambiguous, the team says.

They call for greater interdisciplinary research to shed more light on how lifelike deposits could form on Mars, and thereby aid the search for there and elsewhere in the solar system.

The research is published in the Journal of the Geological Society.

Dr. Sean McMahon, Chancellor’s Fellow in Astrobiology at the University of Edinburgh’s School of Physic and Astronomy, said: “At some stage a Mars rover will almost certainly find something that looks a lot like a fossil, so being able to confidently distinguish these from structures and substances made by chemical reactions is vital. For every type of fossil out there, there is at least one non-biological process that creates very similar things, so there is a real need to improve our understanding of how these form.”

Julie Cosmidis, Associate Professor of Geobiology at the University of Oxford, said: “We have been fooled by life-mimicking processes in the past. On many occasions, objects that looked like fossil microbes were described in ancient rocks on Earth and even in meteorites from Mars, but after deeper examination they turned out to have non-biological origins. This article is a cautionary tale in which we call for further research on life-mimicking processes in the context of Mars, so that we avoid falling into the same traps over and over again.”



Citation:
Life on Mars search could be misled by false fossils, study says (2021, November 16)
retrieved 16 November 2021
from https://phys.org/news/2021-11-life-mars-misled-false-fossils.html

This document is subject to copyright. Apart from any fair dealing for the

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