Spiders, scorpions use leg genes to grow their heads

March 26 (UPI) — Arachnids don’t need specialized genes to develop a head. According to a new study published this week in the journal PNAS, they simply use their leg genes.

University of Wisconsin-Madison researchers Emily Setton and Prashant Sharma were searching for the evolutionary origins of spinnerets, the organs that allow spiders to spin silk threads. To suss out genetic links between spinnerets and spiders’ legs, the researchers silenced leg development genes in arachnid embryos. When they did so, the tiny spiders not only failed to develop legs, they also failed to grow heads.

“Evolution doesn’t want to reinvent the wheel,” Setton said in a news release.

Followup analysis showed both spiders and scorpions use the genes Sp6-9 and Dll to manage head development. The genes code for leg development in most arthropods.

It’s not the first time scientists have found the same genes serving a variety of purposes across different species. For example, the same gene is used to code for jaw bones in reptiles and ear bones in humans.

The latest discovery is, however, a reminder of the evolutionary efficiency of the arthropod, a group that’s adapted to land, water and air. Setton and Sharma believe arthropods hold many of the secrets of genetic evolution and adaptation.

“We study spiders, scorpions and others to help build a more complete evolutionary story and look at what’s going on in the complex world of arthropods,” said Setton.

The researchers hope more of their genetic tricks will be revealed by the phylum’s many unusual members.

“We work with really difficult animals to study,” Sharma said. “A big question of the lab is how is diversity built genetically, evolutionarily? How are ancient lineages related, and what are the genetic mechanisms that underlie the differences between them?”

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'Invisible' display: Cal researchers design atomically-thin, light-emitting device

March 26 (UPI) — Engineers have developed a light-emitting display so thin it disappears when turned off.

The device, designed by scientists at the University of California, Berkeley, was built using a monolayer semiconductor and measures just three-atoms thick.

“The materials are so thin and flexible that the device can be made transparent and can conform to curved surfaces,” Der-Hsien Lien, a postdoctoral fellow at Cal, said in a news release.

In 2015, Ali Javey, a professor of electrical engineering and computer sciences at Berkeley, published research showing monolayer semiconductors are capable of emitting bright light. The latest research, published this week in the journal Nature Communications, expands on Javey’s work.

Scientists working in Javey’s lab were able to overcome a number of technological barriers and scale-up monolayer semiconductor technology described in 2015 by several orders of magnitude. By scaling-up the technology, researchers were able to stretch the semiconductor’s lateral dimensions enough to create a display capable of emitting bright light.

Light-emitting semiconductors require a pair of “contacts,” or inputs, to deliver a negative and positive charge. This necessity has limited the ability of engineers to shrink the thickness of semiconductor displays.

The new ultra thin device designed by Berkeley researchers features only a single contact. By laying the semiconductor monolayer on an insulator embedded with electrodes, engineers were able to deliver an AC current that switches from positive to negative. The two charges move simultaneously through the semiconductor, causing the device to emit light.

The proof-of-concept device is not very energy efficient, but with future improvements, scientists hope the technology could pave the way for an invisible smart display that could be installed on walls and windows — or even used to create light-up tattoos.

“A lot of work remains to be done and a number of challenges need to be overcome to further advance the technology for practical applications,” Javey said. “However, this is one step forward by presenting a device architecture for easy injection of both charges into monolayer semiconductors.”

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Researchers investigate if Hurricane Harvey helped fire ants spread in Texas

March 26 (UPI) — Scientists at Rice University are trying to measure the impact of Hurricane Harvey on fire ant populations, an invasive species common throughout the South.

Previous studies suggest invasive species take over and thrive in damaged ecosystems. Hurricane Harvey offered ecologists another chance to test the theory.

“Hurricane Harvey was, among other things, a grand ecological experiment,” Rice ecologist Tom Millersaid in a news release. “It offers a unique opportunity to explore whether a single extreme-weather event can re-shuffle an entire community of organisms.”

With support from the National Science Foundation’s Rapid Response Research, Miller and his colleagues are conducting monthly surveys of fire ant and tawny crazy ant populations in Big Thicket, a heavily forested national preserve in southeast Texas. Scientists at Rice had been monitoring research sites in Big Thicket for three years prior to the arrival of Hurricane Harvey, noting the steady encroachment of the two invasive ant species.

“We now want to know whether Harvey accelerated this invasion process,” said researcher Sarah Bengston.

In addition to measuring species’ abundance and distribution, researchers will also collect and analyze genetic samples to determine whether Hurricane Harvey proved advantageous for certain traits.

“There are dozens of native ant species in the preserve that provide valuable ecosystem services like decomposition and pest control,” ecologist Scott Solomon said. “Fire ants and crazy ants, which are each native to South America, are noxious invasive pests that tend to overwhelm and drive out almost all native ant species. If the floods cleaned the slate by drowning all the native ant colonies in the area, our hypothesis is that this may provide a competitive advantage to invaders.”

There wasn’t much ant activity during this year’s cold winter, but as temperatures warm, the insects will reemerge.

The research is similar to work being carried out by scientists at the University of Oklahoma. Researchers there continue to monitor the impacts of historic flooding on insect and invertebrate communities in south-central Oklahoma. The early results of their efforts showed the flood caused a sharp decrease in abundance, as well as declines in species presence, biomass and diversity.

As extreme weather evens become more common due to climate change, it is important for scientists to understand how local ecosystems will be affected.

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Instruments for NASA Mars mission undergo testing in Germany

March 23 (UPI) — Scientists in Germany are working hard to ensure NASA’s next Mars mission, the Insight mission, gets the most accurate data possible.

Researchers are currently testing a replica of the probe’s SEIS instrument package, a combination of six seismometers that will be used to study geologic structures deep beneath the Martian surface. The testing will help scientists back in the United States properly calibrate the real SEIS instrument package.

The testing is being carried out at the Joint Geoscientific Observatory, or Black Forest Observatory, BFO, in Schiltach, by a team of researchers from the Karlsruhe Institute of Technology and Stuttgart University.

The combination of three short-period seismometers and three broadband seismometers allows the instrument package to target a wide range of frequencies.

“Ground movement in vertical and two horizontal directions can be measured,” BFO researcher Rudolf Widmer-Schnidrig said in a news release.

The instruments were developed by engineers in France and the United States, and have previously been tested at BFO. Earlier tests focused on a pair of short-period seismometers, while a single broadband seismometer is the focus of the latest round of testing. All the tests will offer a baseline under optimal conditions against which scientists can compare the data returned by the real instrument package.

“At the BFO, we have excellent measurement conditions. Seismic noise is low. The seismometers supply data with the lowest noise worldwide,” Widmer-Schnidrig said.

Scientists are testing the instruments inside measurement chambers installed in the tunnel system of a former ore mine in the Black Forest. At nearly 500 feet beneath Earth’s surface, the testing chambers protect instruments from air pressure and temperature fluctuation, as well as interference from communication systems.

NASA’s Insight probe is scheduled to launch in May and reach Mars in November. Once on the Red Planet, the lander will use an array of sophisticated geophysical instruments to study the interior of the Red Planet. Scientists hope the lander’s observations will yield new insights into the planet’s formation and geologic evolution, including details about the composition and size of Mars’ core and mantle-like intermediate layers.

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Watch live: Capsule carrying new crew to dock at space station on Friday

March 23 (UPI) — The International Space Station’s newest crew members, including two NASA astronauts, are scheduled to arrive at the Poisk module on Friday afternoon.

NASA astronauts Ricky Arnold, Drew Feustel and Roscomos cosmonaut Oleg Artemyev are en route to the space station in the MS-08 spacecraft that launched from Kazakhstan on Wednesday. They are set to arrive at approximately 5:45 p.m. ET.

The crew-carrying capsule will be received and docked with the help of the space station’s current crew, NASA’s Scott Tingle, as well as Expedition 55 Commander Anton Shkaplerov of Roscosmos and Norishige Kanai of the Japan Aerospace Exploration Agency.

NASA TV will livestream the arrival and docking activities beginning at 3 p.m. The hatch will be opened and the new crew members will be welcomed to the space station at 5 p.m.

Once joined by Arnold, Feustel and Artemyev, the expanded six-person crew will remain together until June, when Tingle, Shkaplerov and Kanai will travel back Earth. Feustel, Arnold and Artemyev will remain on the ISS until August.

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New device can harvest water from arid desert air

March 22 (UPI) — In field tests, a new water-harvesting device successfully pulled water from the desert air in Tempe, Arizona. The new technology could allow humans to survive in some of the most inhospitable regions on Earth.

The new device — described this week in the journal Nature — is an improved version of the initial iteration, first described last year. When researchers at MIT first unveiled the device in 2017, skeptics voice a number of criticisms.

“All of the questions that were raised from last time were explicitly demonstrated in this paper,” Evelyn Wang, a professor of mechanical engineering at MIT, said in a news release. “We’ve validated those points.”

The device uses metal-organic frameworks, a unique material with an expansive internal surface area and molecule-trapping structures. Current water-harvesting devices require high humidity levels and are energy intensive.

The MOFs used in the device are made from water-attracting materials and painted black on top to encourage the absorption of sunlight. The water vapor is pulled into the material’s tiny inner pores where the difference in temperature and concentration causes the vapor to condense and drip to the bottom.

Scientists field-tested their new device on the roof of an Arizona State University building — “in a place that’s representative of these arid areas, and showed that we can actually harvest the water, even in subzero dew points,” Wang said.

The new device was powered only by sunlight. At present, the prototype is small, but researchers say it can easily be scaled up. Tests showed the device harvests a quarter-liter of water per day per kilogram of MOF material. Tests also showed the water is potable and free of impurities.

Because the device has no moving parts, scientists are confident that the technology is practical and can be deployed in the field.

By scaling up the technology and perfecting the metal-organic framework, scientists hope to triple the water output of their technology.

“We hope to have a system that’s able to produce liters of water,” Wang said. “We want to see water pouring out!”

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