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Symbiotic bacteria in planthoppers break record for smallest non-organelle genome ever found

Many insects rely on heritable bacterial endosymbionts for essential nutrients that they cannot get through their diet. A new study, published in Nature Communications, indicates that the genomes of these symbiotic bacteria often shrink over time. Some of these bacteria, which live inside certain insect cells, have lost so many genes that they have broken the record for the tiniest genome ever found—almost blurring the lines between organelle and bacteria.

Endosymbiotic relationships are common in many insects, and in sap-sucking insects, like planthoppers and cicadas, they are essential for the insect’s survival. Because the sap of plants does not typically contain certain amino acids or vitamins, the insect must get them another way. Over hundreds of millions of years, these insects have co-evolved with bacteria that provide these additional nutrients.

Sulcia and Vidania are two examples of bacterial endosymbionts, which have co-evolved with planthoppers for more than 260 million years. These bacteria live in specialized cells within the planthopper abdomen. The new study has found that, along with their hosts, these endosymbionts have evolved—or devolved—in some unexpected ways.

The persistence of gravitational wave memory

Neutron stars are ultra-dense remnants of massive stars that collapsed after supernova explosions and are made up mostly of subatomic particles with no electric charge (i.e., neutrons). When two neutron stars collide, they are predicted to produce gravitational waves, ripples in the fabric of spacetime that travel at the speed of light.

Gravitational waves typically take the form of oscillations, periodically and temporarily influencing the universe’s underlying fabric (i.e., spacetime). However, general relativity suggests that for some cosmological events, in addition to the oscillatory displacement of test masses (as produced by the passage of a gravitational wave train), there exists a final permanent displacement of them via a phenomenon referred to as “gravitational wave memory.”

Researchers at the University of Illinois at Urbana-Champaign, the Academy of Athens, the University of Valencia and Montclair State University recently carried out a study exploring the gravitational wave memory effects that would arise from neutron star mergers.

Atom-thin electronics withstand space radiation, potentially surviving for centuries in orbit

Atom-thick layers of molybdenum disulfide are ideally suited for radiation-resistant spacecraft electronics, researchers in China have confirmed. In a study published in Nature, Peng Zhou and colleagues at Fudan University put a communications system composed of the material through a gauntlet of rigorous tests—including the transmission of their university’s Anthem—confirming that its performance is barely affected in the harsh environment of outer space.

Beyond the protection of Earth’s magnetic field, the electronic components of modern spacecraft are extremely vulnerable to constant streams of cosmic rays and heavy ions. While onboard systems can be shielded with radiation-protective materials, this approach takes up valuable space and adds weight to spacecraft.

That extra mass drives up launch costs and can limit the payload available for scientific instruments or communications hardware. A far better solution would be to fabricate the electronics themselves from materials that are intrinsically resistant to radiation damage.

Supercomputer simulations reveal rotation drives chemical mixing in red giant stars

Advances in supercomputing have made solving a long‐standing astronomical conundrum possible: How can we explain the changes in the chemical composition at the surface of red giant stars as they evolve?

For decades, researchers have been unsure exactly how the changing chemical composition at the center of a red giant star, caused by nuclear burning, connects to changes in composition at the surface. A stable layer acts as a barrier between the star’s interior and the outer connective envelope, and how elements cross that layer remained a mystery.

In a Nature Astronomy paper, researchers at the University of Victoria’s (UVic) Astronomy Research Center (ARC) and the University of Minnesota solved the problem.

AI ‘blind spot’ could allow attackers to hijack self-driving vehicles

A newly discovered vulnerability could allow cybercriminals to silently hijack the artificial intelligence (AI) systems in self-driving cars, raising concerns about the security of autonomous systems increasingly used on public roads. Georgia Tech cybersecurity researchers discovered the vulnerability, dubbed VillainNet, and found it can remain dormant in a self-driving vehicle’s AI system until triggered by specific conditions. Once triggered, VillainNet is almost certain to succeed, giving attackers control of the targeted vehicle.

The research finds that attackers could program almost any action within a self-driving vehicle’s AI super network to trigger VillainNet. In one possible scenario, it could be triggered when a self-driving taxi’s AI responds to rainfall and changing road conditions. Once in control, hackers could hold the passengers hostage and threaten to crash the taxi.

The researchers discovered this new backdoor attack threat in the AI super networks that power autonomous driving systems.

New chip-fabrication method creates ‘twin’ fingerprints for direct authentication

Just like each person has unique fingerprints, every CMOS chip has a distinctive “fingerprint” caused by tiny, random manufacturing variations. Engineers can leverage this unforgeable ID for authentication, to safeguard a device from attackers trying to steal private data.

But these cryptographic schemes typically require secret information about a chip’s fingerprint to be stored on a third-party server. This creates security vulnerabilities and requires additional memory and computation.

To overcome this limitation, MIT engineers developed a manufacturing method that enables secure, fingerprint-based authentication, without the need to store secret information outside the chip.

How choices made by crowds in a train station are guided by strangers

In crowds, most people are strangers to you, and everyone else for that matter. However, until now, the effect of stranger-to-stranger interactions on the choices people make in crowds has not been properly examined. Ziqi Wang and Federico Toschi from the TU/e Department of Applied Physics and Science Education, along with Alessandro Gabbana at the University of Ferrara in Italy, explored how strangers influence people’s choices in crowds at Eindhoven Centraal railway station. The research is published in the journal Proceedings of the National Academy of Sciences.

“Using a collection of special overhead sensors, we gathered data on how pedestrians move over a three-year period, from March 2021 to March 2024,” says Toschi. “This amounted to about 30,000,000 pedestrian trajectories and included people getting off trains and those waiting on the platform. We collaborated with ProRail on this project, as we have done in previous studies on how pedestrians move in Eindhoven Centraal station.”

Toschi has been studying pedestrian dynamics for some time and was jointly awarded the 2021 Ig Nobel Prize for physics for work on how pedestrians keep a certain distance from each other in crowds.

Neutron scattering helps clarify magnetic behavior in altermagnetic material

Scientists at the U.S. Naval Research Laboratory (NRL) have identified the true source of a magnetic effect seen in the material ruthenium dioxide (RuO₂), helping resolve an active debate in the rapidly growing field of altermagnetism. The study is published in the journal ACS Applied Materials & Interfaces.

RuO₂ has drawn global attention as a possible “altermagnetic” material, a newly predicted class of materials that could enable faster, more energy-efficient computing technologies. The excitement has been fueled by theory and early experimental reports suggesting that RuO₂ might host an unusual magnetic state with major implications for spintronics and high-speed electronics.

“Altermagnets are a hot field of research right now,” said Steven Bennett, Ph.D., an NRL materials scientist and co-author of the study. “There’s been a rush to experimentally demonstrate what theorists predicted, because the impact on high-speed, energy-efficient computing could be significant.”

Quantum trembling: Why there are no truly flat molecules

Traditional chemistry textbooks present a tidy picture: Atoms in molecules occupy fixed positions, connected by rigid rods. A molecule such as formic acid (methanoic acid, HCOOH) is imagined as two-dimensional—flat as a sheet of paper. But quantum physics tells a different story. In reality, nature resists rigidity and forces even the simplest structures into the third dimension.

Researchers led by Professor Reinhard Dörner of the Institute for Nuclear Physics at Goethe University have now determined the precise spatial structure of the “flat” formic acid molecule using an X-ray beam from the PETRA III synchrotron radiation source at the DESY accelerator center in Hamburg. They collaborated with colleagues from the universities of Kassel, Marburg and Nevada, the Fritz Haber Institute, and the Max Planck Institute for Nuclear Physics. The study is published in Physical Review Letters.

To accomplish this, they made use of two effects that occur when X-ray radiation strikes a molecule. First, the radiation ejects several electrons from the molecule (photoelectric effect and Auger effect). As a result, the atoms become so highly charged that the molecule bursts apart in an explosion (Coulomb explosion). The scientists succeeded in measuring these processes sequentially, even though they take place within femtoseconds—millionths of a billionth of a second.

Impact-formed glass provides evidence of cosmic collision in Brazil about 6 million years ago

For the first time in Brazil, researchers have identified a field of tektites. These are natural glasses formed by the high-energy impact of extraterrestrial bodies against Earth’s surface. These structures, named geraisites in honor of the Brazilian state of Minas Gerais, where they were first discovered, constitute a new strewn field. This expands the incomplete record of impacts in South America.

The discovery was described in an article published in the journal Geology by a team led by Álvaro Penteado Crósta, a geologist and senior professor at the Institute of Geosciences at the State University of Campinas (IG-UNICAMP). Crósta collaborated with researchers from Brazil, Europe, the Middle East, and Australia.

Until now, only five large tektite fields had been recognized on the planet: in Australasia, Central Europe, the Ivory Coast, North America, and Belize. The Brazilian field now joins this select group.

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