Aurelia Butler

Researchers with the University of Chicago Pritzker School of Molecular Engineering have shown for the first time how to design the basic elements needed for logic operations using a kind of material called a liquid crystal — paving the way for a completely novel way of performing computations.
The results, published Feb. 23 in Science Advances, are not likely to become transistors or computers right away, but the technique could point the way towards devices with new functions in sensing, computing and robotics.
“We showed you can create the elementary building blocks of a circuit — gates, amplifiers, and conductors — which means you should be able to assemble them into arrangements capable of performing more complex operations,” said Juan de Pablo, the Liew Family Professor in Molecular Engineering and senior scientist at Argonne National Laboratory, and the senior corresponding author on the paper. “It’s a really exciting step for the field of active materials.”
The details in the defect
The research aimed to take a closer look at a type of material called a liquid crystal. The molecules in a liquid crystal tend to be elongated, and when packed together they adopt a structure that has some order, like the straight rows of atoms in a diamond crystal — but instead of being stuck in place as in a solid, this structure can also shift around as a liquid does. Scientists are always looking for these kinds of oddities because they can utilize these unusual properties as the basis of new technologies; liquid crystals, for example, are in the LCD TV you may already have in your home or in the screen of your laptop.
One consequence of this odd molecular order is that there are spots in all liquid crystals where the ordered regions bump up against each other and their orientations don’t quite match, creating what scientists call “topological defects.” These spots move around as the liquid crystal moves. More

A rare spectroscopy technique performed at Swinburne University of Technology directly quantifies the energy required to bind two excitons together, providing for the first time a direct measurement of the biexciton binding energy in WS2.
As well as improving our fundamental understanding of biexciton dynamics and characteristic energy scales, these findings directly inform those working to realise biexciton-based devices such as more compact lasers and chemical-sensors.
The study also brings closer exotic new quantum materials, and quantum phases, with novel properties.
The study is a collaboration between FLEET researchers at Swinburne and the Australian National University.
Understanding Excitons
Particles of opposite charge in close proximity will feel the ‘pull’ of electrostatic forces, binding them together. The electrons of two hydrogen atoms are pulled in by opposing protons to form H2, for example, while other compositions of such electrostatic (Coulomb-mediated) attraction can result in more exotic molecular states. More

Fearsome dire wolves and saber-toothed cats no longer prowl around La Brea Tar Pits, but thanks to new research, anyone can bring these extinct animals back to life through augmented reality (AR). Dr. Matt Davis and colleagues at the Natural History Museum of Los Angeles County and La Brea Tar Pits collaborated with researchers and designers at the University of Southern California (USC) to create more than a dozen new, scientifically accurate virtual models of Ice Age animals, published recently in Palaeontologia Electronica.
The team is investigating how AR impacts learning in museums, but soon realized there weren’t any accurate Ice Age animals in the metaverse yet that they could use. So, they took all the latest paleontological research and made their own. The models were built in a blocky, low poly style so that they could be scientifically accurate, but still simple enough to run on normal cell phones with limited processing power.
According to study co-author Dr. William Swartout, Chief Technology Officer at the USC Institute for Creative Technologies, “The innovation of this approach is that it allows us to create scientifically accurate artwork for the metaverse without overcommitting to details where we still lack good fossil evidence.”
The researchers hope this article will also bring more respect to paleoart, the kind of art that recreates what extinct animals might have looked like. “Paleoart can be very influential in how the public, and even scientists, understand fossil life,” said Dr. Emily Lindsey, Assistant Curator at La Brea Tar Pits and senior author of the study. A lot of paleoart is treated as an afterthought, though, and not subjected to the same rigorous scrutiny as other scientific research. This can lead to particularly bad reconstructions of extinct animals being propagated for generations in both the popular media and academic publications.
“We think paleoart is a crucial part of paleontological research,” said Dr. Davis, the study’s lead author. “That’s why we decided to publish all the scientific research and artistic decisions that went into creating these models. This will make it easier for other scientists and paleoartists to critique and build off our team’s work.”
Dr. Davis notes that it is just as important to acknowledge what we don’t know about these animals’ appearances as it is to record what we do know. For example, we can accurately depict the shaggy fur of Shasta ground sloths because paleontologists have found a whole skeleton of this species with hair and skin still preserved. But for mastodons, paleontologists have only found a few strands of hair. Their thick fur pelt was an artistic decision. Dr. Davis and colleagues hope that other paleoartists and scientists will follow their example by publishing all the research that goes into their reconstructions of extinct species. It will lead to better and more accurate paleoart for everyone.
This research was funded by an NSF AISL collaborative grant (1811014; 1810984) led by Dr. Benjamin Nye of the USC Institute for Creative Technologies, Dr. Gale Sinatra of the USC Rossier School of Education, Dr. William Swartout of the USC Institute for Creative Technologies, and Dr. Emily Lindsey of La Brea Tar Pits.
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Materials provided by Natural History Museum of Los Angeles County. Note: Content may be edited for style and length. More

Scientists found that ants and other natural systems use optimization algorithms similar to those used by engineered systems, including the Internet. These algorithms invest incrementally more resources as long as signs are encouraging but pull back quickly at the first sign of trouble. The systems are designed to be robust, allowing for portions to fail without harming the entire system. Understanding how these algorithms work in the real world may help solve engineering problems, whereas engineered systems may offer clues to understanding the behavior of ants, cells, and other natural systems.
Engineers sometimes turn to nature for inspiration. Cold Spring Harbor Laboratory Associate Professor Saket Navlakha and research scientist Jonathan Suen found that adjustment algorithms — the same feedback control process by which the Internet optimizes data traffic — are used by several natural systems to sense and stabilize behavior, including ant colonies, cells, and neurons.
Internet engineers route data around the world in small packets, which are analogous to ants. As Navlakha explains:
“The goal of this work was to bring together ideas from machine learning and Internet design and relate them to the way ant colonies forage.”
The same algorithm used by Internet engineers is used by ants when they forage for food. At first, the colony may send out a single ant. When the ant returns, it provides information about how much food it got and how long it took to get it. The colony would then send out two ants. If they return with food, the colony may send out three, then four, five, and so on. But if ten ants are sent out and most do not return, then the colony does not decrease the number it sends to nine. Instead, it cuts the number by a large amount, a multiple (say half) of what it sent before: only five ants. In other words, the number of ants slowly adds up when the signals are positive, but is cut dramatically lower when the information is negative. Navlakha and Suen note that the system works even if individual ants get lost and parallels a particular type of “additive-increase/multiplicative-decrease algorithm” used on the Internet.
Suen thinks ants might inspire new ways to protect computer systems against hackers or cyberattacks. Engineers could emulate how nature withstands a range of threats to health and viability. Suen explains:
“Nature has been shown to be incredibly robust in a lot of aspects responding to changing environments. In cybersecurity [however] we find that a lot of our systems can be tampered with, can be easily broken, and are simply not robust. We wanted to look at nature, which survives across all sorts of natural disasters, evolutionary changes, human changes, and learn a lot from how nature changes its systems dynamically to survive.”
While Suen plans to apply nature’s algorithms to engineering programs, Navlakha would like to see if engineering solutions might offer alternative approaches to understanding gene regulation and immune feedback control. Navlakha hopes that “successful strategies in one realm could lead to improvements in the other.”
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Materials provided by Cold Spring Harbor Laboratory. Original written by Eliene Augenbraun. Note: Content may be edited for style and length. More

The end of the Permian was characterized by the greatest mass extinction event in Earth’s history. 252 million years ago, a series of volcanic eruptions in Siberia led to a massive release of greenhouse gases. In the course of the next several millennia, the climate ultimately warmed by ten degrees. As a consequence, on land, roughly 75 percent of all organisms went extinct; in the oceans, the number was roughly 90 percent.
By analyzing how the now-extinct marine organisms once lived, Dr. Foster and his team were able to directly link their extinction to the following climate changes: declining oxygen levels in the water, rising water temperatures, and most likely also ocean acidification.
These changes are similar to current trends. “Needless to say, our findings on the Permian can’t be applied to modern climate change one-to-one. The two climate systems are far too different,” says Foster, a geoscientist. “Yet they do show which traits were critical for an organism’s survival or extinction- under similar conditions. This can offer us valuable indicators for who or what will be at the greatest risk in the future.”
Specifically, the team analyzed more than 25,000 records on 1283 genera of fossil marine organisms like bivalves, snails, sponges, algae and crustaceans from the region of South China — all of which had mineral skeletons or shells. Their fossilized remains can be dated using a special method, offering insights into marine ecosystems dating back millions of years. The team also drew on an enormous database that offers additional information on various ecological aspects of how these organisms lived.
For each genus, twelve of these criteria were analyzed. Did certain traits make a given organism more likely to survive under the conditions prevalent at the end of the Permian — or not? With the aid of machine learning, a method from the field of Artificial Intelligence, all of these factors were analyzed jointly and simultaneously. In the process, the machine essentially made certain rational decisions on its own. Once this was done, the team compared the results: what organisms were there before, during and after the mass extinction?
Their findings reveal the four factors that were most essential to whether or not organisms survived the end of the Permian: where in the water they lived, the mineralization of their shells, species diversity within their genus, and their sensitivity to acidification.
“But with previous machine learning applications, we couldn’t say how the machine made its decisions.” Using a newly implemented method from games theory, Dr. Foster has now succeeded in unraveling this aspect: “Some animals lived in deeper water. Here, the machine shows that the worsening lack of oxygen posed a risk. In contrast, those animals that lived nearer the surface had to contend with the rising water temperatures. Plus, when you have only a limited habitat, you have nowhere to go when that specific habitat becomes uninhabitable.” As such, the results show which of the organisms’ traits were determined to be potentially fatal. The team was ultimately able to confirm that the mass extinction can be directly attributed to deoxygenation, rising water temperatures and acidification — which indicates that, in a future climate crisis, these could also be the three main causes of extinction in the long term.
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Materials provided by University of Hamburg. Original written by Stephanie Janssen. Note: Content may be edited for style and length. More

Liquid crystals could soon be produced more efficiently and in a more environmentally friendly way. A new process has been developed by researchers at Martin Luther University Halle-Wittenberg (MLU) in Germany, Bangalore University in India and Cairo University in Egypt. Compared to conventional methods, it is faster, more energy-efficient and promises a high yield as the team reports in the Journal of Molecular Liquids. Liquid crystals are used in most smartphone, tablet and computer displays.
The production of liquid crystals is a complex process with many intermediate steps. “Often it requires various solvents and expensive catalysts,” says Dr Mohamed Alaasar, a chemist at MLU. The team from Germany, India and Egypt was looking for a way to simplify the process and make it more environmentally friendly. The idea: instead of the chemical reactions taking place one after the other, certain steps could be combined in a so-called multicomponent reaction in which several substances react directly with one another.
The team developed an approach for producing liquid crystals which does not require environmentally harmful solvents and relies on cheaper catalysts. “We were able to achieve a yield of about 90 per cent. This means that most of the chemicals are used in the process and relatively few residues are produced,” explains Alaasar. This saves energy and ultimately also money. At room temperature the newly created liquid crystals are in a nematic phase — a special arrangement of molecules used in most liquid crystal displays or LCDs.
So far, the researchers have only tested their new process in the laboratory. However, Alaasar is confident that it could also be implemented on an industrial scale. “However, manufacturers would have to rebuild parts of their manufacturing. This has not happened in the past with other promising materials,” says the scientist. However, consumers started valuing sustainability and more environmentally friendly products of the last years. That could be an additional argument in favour for the new approach.
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Materials provided by Martin-Luther-Universität Halle-Wittenberg. Note: Content may be edited for style and length. More

A series of experiments using paper airplanes reveals new aerodynamic effects, a team of scientists has discovered. Its findings enhance our understanding of flight stability and could inspire new types of flying robots and small drones.
“The study started with simple curiosity about what makes a good paper airplane and specifically what is needed for smooth gliding,” explains Leif Ristroph, an associate professor at New York University’s Courant Institute of Mathematical Sciences and an author of the study, which appears in the Journal of Fluid Mechanics. “Answering such basic questions ended up being far from child’s play. We discovered that the aerodynamics of how paper airplanes keep level flight is really very different from the stability of conventional airplanes.”
“Birds glide and soar in an effortless way, and paper airplanes, when tuned properly, can also glide for long distances,” adds author Jane Wang, a professor of engineering and physics at Cornell University. “Surprisingly, there has been no good mathematical model for predicting this seemingly simple but subtle gliding flight.”
Since we can make complicated modern airplanes fly, the researchers say, one might think we know all there is to know about the simplest flying machines.
“But paper airplanes, while simple to make, involve surprisingly complex aerodynamics,” notes Ristroph.
The paper’s authors began their study by considering what is needed for a plane to glide smoothly. Since paper airplanes have no engine and rely on gravity and proper design for their movement, they are good candidates for exploring factors behind flight stability. More

Hearing loss is a rapidly growing area of scientific research as the number of baby boomers dealing with hearing loss continues to increase as they age.
To understand how hearing loss impacts people, researchers study people’s ability to recognize speech. It is more difficult for people to recognize human speech if there is reverberation, some hearing impairment, or significant background noise, such as traffic noise or multiple speakers.
As a result, hearing aid algorithms are often used to improve human speech recognition. To evaluate such algorithms, researchers perform experiments that aim to determine the signal-to-noise ratio at which a specific number of words (commonly 50%) are recognized. These tests, however, are time- and cost-intensive.
In The Journal of the Acoustical Society of America, published by the Acoustical Society of America through AIP Publishing, researchers from Germany explore a human speech recognition model based on machine learning and deep neural networks.
“The novelty of our model is that it provides good predictions for hearing-impaired listeners for noise types with very different complexity and shows both low errors and high correlations with the measured data,” said author Jana Roßbach, from Carl Von Ossietzky University.
The researchers calculated how many words per sentence a listener understands using automatic speech recognition (ASR). Most people are familiar with ASR through speech recognition tools like Alexa and Siri.
The study consisted of eight normal-hearing and 20 hearing-impaired listeners who were exposed to a variety of complex noises that mask the speech. The hearing-impaired listeners were categorized into three groups with different levels of age-related hearing loss.
The model allowed the researchers to predict the human speech recognition performance of hearing-impaired listeners with different degrees of hearing loss for a variety of noise maskers with increasing complexity in temporal modulation and similarity to real speech. The possible hearing loss of a person could be considered individually.
“We were most surprised that the predictions worked well for all noise types. We expected the model to have problems when using a single competing talker. However, that was not the case,” said Roßbach.
The model created predictions for single-ear hearing. Going forward, the researchers will develop a binaural model since understanding speech is impacted by two-ear hearing.
In addition to predicting speech intelligibility, the model could also potentially be used to predict listening effort or speech quality as these topics are very related.
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Materials provided by American Institute of Physics. Note: Content may be edited for style and length. More