Chaos on the Nanometer Scale

Nanochaos on an asymmetric Rhodium nanocrystal
Illustration Credit: Vienna University of Technology

Sometimes, chemical reactions do not solely run stationary in one direction, but they show spatio-temporal oscillations. At TU Wien, a transition to chaotic behavior on the nanometer scale has now been observed.

Chaotic behavior is typically known from large systems: for example, from weather, from asteroids in space that are simultaneously attracted by several large celestial bodies, or from swinging pendulums that are coupled together. On the atomic scale, however, one does normally not encounter chaos – other effects predominate. Now, for the first time, scientists at TU Wien have been able to detect clear indications of chaos on the nanometer scale – in chemical reactions on tiny rhodium crystals. The results have been published in the journal Nature Communications.

Climate Trends in the West, Today and 11,000 Years Ago

UC Davis students hike in the Grand Canyon, a landscape that has changed dramatically over the past thousands and millions of years.
Photo Credit: Joe Proudman/UC Davis

People often say things like Phoenix has always been dry; Seattle has always been wet; and San Francisco has always been foggy. But “always” is a strong word. 

A study from the University of California, Davis, synthesizes climate trends across the Western U.S. during a relatively young period of Earth’s history — the Holocene Era, which stretches from the present day to the past 11,000 years. This look at the really Old West shows that the hallmarks of California’s climate — the foggy coastlines that gave rise to towering redwoods, the ocean upwelling that spawned productive fisheries, the warm summers and mild winters — began around 4,000 years ago. 

It also reveals a time when the Pacific Northwest was warm and dry and the Southwest was warm and wet.

Mysteries of the Earth: FSU researchers predict how fast ancient magma ocean solidified

An illustration of Earth as it existed during part of its formation billions of years ago, when an ocean of magma covered the surface of the planet and stretched thousands of miles deep into the core. A typical cell from a simulation conducted by FSU researchers with the relative positions of atoms are shown in the left
Illustration Credit: Courtesy of Suraj Bajgain / Lake Superior State University

Early in the formation of Earth, an ocean of magma covered the planet’s surface and stretched thousands of miles deep into its core. The rate at which that “magma ocean” cooled affected the formation of the distinct layering within the Earth and the chemical makeup of those layers.

Previous research estimated that it took hundreds of million years for that magma ocean to solidify, but new research from Florida State University published in Nature Communications narrows these large uncertainties down to less than just a couple of million years.

“This magma ocean has been an important part of Earth’s history, and this study helps us answer some fundamental questions about the planet,” said Mainak Mookherjee, an associate professor of geology in the Department of Earth, Ocean and Atmospheric Science.

When magma cools, it forms crystals. Where those crystals end up depends on how viscous the magma is and the relative density of the crystals. Crystals that are denser are likely to sink and thus change the composition of the remaining magma. The rate at which magma solidifies depends on how viscous it is. Less viscous magma will lead to faster cooling, whereas a magma ocean with thicker consistency will take a longer time to cool.

London falcons ate fewer pigeons during lockdowns

Peregrine falcon
Photo Credit: Jasmin777

The study by King’s researchers suggests that predatory birds in urban spaces are vulnerable to changes in human activities that support prey populations.

Changes in peregrine falcon diets during COVID-19 lockdowns highlight the impact of human behavior on urban predators. The findings are from a new study co-authored by King’s researchers published in the British Ecological Society journal, People and Nature.

Researchers from King’s College London and University of Bristol found that during lockdowns, peregrine falcons in London were forced to change their diet away from pigeons since fewer of these birds were being drawn in by human food supplies such as discarded food waste or direct feeding.

Brandon Mak, a PhD student in the Department of Geography who co-led the study with Ed Drewitt from the University of Bristol, said: “Our results indicate that peregrines in larger, highly urbanized cities like London may be more dependent on, and hence more vulnerable to changes in, human activities which support their prey populations, particularly feral pigeons.”

Producing extreme ultraviolet laser pulses efficiently through wakesurfing behind electron beams

A 3D simulation of the wake behind the electron beam (purple) and how a light pulse (blue and red stripe) might surf behind it. The plasma wake is shown in alternating yellow for the absence of electrons and green for peaks in the electron density. When a light pulse sits on that boundary, it can continuously gain energy—the trick is keeping it there.
Image Credit: Ryan Sandberg, High Field Science Group

Simulations suggest this mechanism could provide a tenfold increase in frequency—likely hitting a peak power of 100 trillion watts in XUV

A laser pulse surfing in the wake of an electron beam pulse could get upshifted from visible to extreme ultraviolet light, simulations done at the University of Michigan have shown.

The approach could enable more efficient generation of high-energy laser light, perhaps even to X-rays. The 3D simulation showed up to a tenfold increase in the frequency of the light, while the 1D simulation went up to a 50-fold increase. In principle, the researchers say it is possible to continue amping up the energy of the laser pulse by extending the period of time that it can ride in the wake of the electron beam.

“Future lasers, potentially including those used to pattern semiconductor chips for computers, could take advantage of this effect to produce higher energy pulses more efficiently,” said Alec Thomas, U-M professor of nuclear engineering and radiological sciences and corresponding author of the study in Physical Review Letters.

Dinosaur claws used for digging and display

Therizinosaurs claw hooking and pulling trees
Image Credit: Shuyang Zhou for the 3D modelling and functional scenario restoration

Dinosaur claws had many functions, but now a team from the University of Bristol and the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing has shown some predatory dinosaurs used their claws for digging or even for display.

The study focused on two groups of theropod dinosaurs, the alvarezsaurs and therizinosaurs, that had weird claws whose function had been a mystery up to now. It turns out that alvarezsaurs used their rock-pick-like claws for digging, but their close relatives, the giant therizinosaurs, used their overdeveloped, meter-long, sickle-like claws for display.

The new work is led by Zichuan Qin, a PhD student at the University of Bristol and the IVPP. He developed a new, computational approach in biomechanics to identify functions based on detailed comparison with living animals. First, the claws were modelled in three dimensions from CT scans, then modelled for stress and strain using engineering methods, and finally matched to functions of pulling, piercing and digging by comparison with modern animals whose claw functions are known.

“Alvarezsaurs and therizinosaurs are definitely the strangest cousins among dinosaurs,” said Professor Michael Benton, one of Zichuan’s supervisors. “Alvarezsaurs were the tiniest dinosaurs ever, the size of chickens, with stubby forelimbs and robust single claws, but their closest relative, the therizinosaurs, evolved in the exact opposite path.”

Hackers could try to take over a military aircraft; can a cyber shuffle stop them?

Sandia National Laboratories cybersecurity expert Chris Jenkins sits in front of a whiteboard with the original sketch of the moving target defense idea for which he is the team lead. When the COVID-19 pandemic hit, Jenkins began working from home, and his office whiteboard remained virtually undisturbed for more than two years.
Photo Credit: Craig Fritz

A cybersecurity technique that shuffles network addresses like a blackjack dealer shuffles playing cards could effectively befuddle hackers gambling for control of a military jet, commercial airliner or spacecraft, according to new research. However, the research also shows these defenses must be designed to counter increasingly sophisticated algorithms used to break them.

Many aircraft, spacecraft and weapons systems have an onboard computer network known as military standard 1553, commonly referred to as MIL-STD-1553, or even just 1553. The network is a tried-and-true protocol for letting systems like radar, flight controls and the heads-up display talk to each other.

Securing these networks against a cyberattack is a national security imperative, said Chris Jenkins, a Sandia National Laboratories cybersecurity scientist. If a hacker were to take over 1553 midflight, he said, the pilot could lose control of critical aircraft systems, and the impact could be devastating.

Jenkins is not alone in his concerns. Many researchers across the country are designing defenses for systems that utilize the MIL-STD-1553 protocol for command and control. Recently, Jenkins and his team at Sandia partnered with researchers at Purdue University in West Lafayette, Indiana, to test an idea that could secure these critical networks.

Voluntary UK initiatives to phase out toxic lead shot for pheasant hunting have had little impact

Pheasant
Photo Credit: Julie Mayo

The pledge, made in 2020 by nine major UK game shooting and rural organizations, aims to protect the natural environment and ensure a safer supply of game meat for consumers. Lead is toxic even in very small concentrations, and discarded shot from hunting poisons and kills tens of thousands of the UK’s wild birds each year.

A Cambridge-led team of 17 volunteers bought whole pheasants from butchers, game dealers and supermarkets across the UK in 2022-23. They dissected the birds at home and recovered embedded shotgun pellets from 235 of the 356 pheasant carcasses.

The main metal present in each shotgun pellet was revealed through laboratory analysis - conducted at the Environmental Research Institute, University of the Highlands and Islands, UK. Lead was the main element in 94% of the recovered shot pellets; the remaining 6% were predominantly composed of steel or a metal called bismuth.

Australia’s rarest bird of prey disappearing at alarming rate

Researchers analyzed 40 years of sightings by citizen scientists to uncover concerning population trends.
Photo Credit: Chris McColl

Australia’s rarest bird of prey - the red goshawk - is facing extinction, with Cape York Peninsula now the only place in Queensland known to support breeding populations.

PhD candidate Chris MacColl from The University of Queensland’s School of Earth and Environmental Sciences led the research project that made the discovery and was shocked by the hawk’s dwindling numbers.

“Over four decades the red goshawk has lost a third of its historical range, which is the area that’s it’s previously been known to occupy,” Mr. MacColl said.

“It’s barely hanging on in another 30 per cent of regions it has previously been known to inhabit.”

Mr. MacColl said the species is now considered extinct in New South Wales and the southern half of Queensland.

Let's get wasted and apply some deep thinking to rubbish

Photo Credit: John Cameron

Artificial intelligence has made a giant leap into our rubbish bins thanks to new technology being deployed at the University of South Australia.

Using algorithms to analyze data from smart bin sensors, UniSA PhD student Sabbir Ahmed is designing a deep learning model to predict where waste is accumulating in cities and how often public bins should be cleared.

“Sensors in the public smart bins can give us a lot of information about how busy specific locations are, what type of rubbish is being disposed of and even how much methane gas is being produced from food waste in bins,” Ahmed says.

“All that data can be fed into a neural network model to predict where bins in parks, shopping centers and other public places are likely to fill up quickly and, conversely, which locations are rarely visited.

“This can help councils to optimize their waste management services, schedule bin clearances and even relocate rarely used bins to where they are needed most.”