Computers Math

Word lists are the basis of so much research in so many fields. Researchers at the Complexity Science Hub have now developed an algorithm that can be applied to different languages and can expand word lists significantly better than others.
Many projects start with the creation of a word list. Not only in companies when mind maps are created, but also in all areas of research. Imagine you want to find out on which days people are in a particularly good mood by analyzing Twitter postings. Just looking for the word “happy” wouldn’t be enough.
Instead, you would have to use an algorithm that detects all tweets that indicate that someone is happy. “So the first step is to create a list of all the words that indicate just that. The whole research stands or falls on doing so,” explains Anna Di Natale, a researcher at the Complexity Science Hub in Vienna. But how to come up with the most accurate, complete word lists possible?
A PROBLEM THAT CONCERNS MANY
This widespread problem not only concerns opinion researchers who want to find out how politicians’ statements are received by the public. Companies, too want to find out how their products are perceived through sentiment analysis.
To improve things, Di Natale has now developed a new method, called LEXpander, that outperforms previous algorithms. And this even in two different languages — German and English. Moreover, for the very first time ever, she has developed a way through which it is possible to compare different tools at all.

IMPROVED PERFORMANCE
In comparison with four other algorithms for wordlist expansion (WordNet, Empath 2.0, FastText and GloVe), LEXpander performed significantly better, especially in German. For example, the researchers found that LEXpander guesses 43% of words right when expanding an English word list for positive meaning. A very popular model, FastText, in comparison, is right only 28% of the time.
INDEPENDENCE FROM THE LANGUAGE ITSELF
The reason is that this tool works language-independently. It is not based on one language, but on a so-called colexification network. This recognized linguistic concept resides on homonyms and polysemies, single words that have two or more distinct meanings. For example: the ancient Greek word φάρμακον (pharmacon) can mean medicine or poison. Two different things, but thematically close. But there are others that don’t suggest kinship — such as “bank” as a financial institution or the land alongside a river.
“If you collect them across many languages — and here we analyzed about 19 different languages — you can see connections between them,” Di Natale says. The network is formed when these colexifications occur in several languages across different language families, creating connections.
This independence from the language itself allows LEXpander to achieve better results in different languages. “There are many methods developed for English. They work very well and quickly and everyone uses them. Trying to apply them to other languages works, but not as well as it might work if you had started developing a method for German or Italian,” Di Natale explains.
IMPORTANT FOR NEW TOPICS LIKE COVID
For many topics there are already good word lists. But for new topics — like when COVID came up — new ones have to be created. Until now, they were usually created by hand during brainstorming with colleagues and several tools were used to help. But until now there was no way to compare them. Anna Di Natale and her team have now created this possibility and have also developed a new tool that performs better than the others. This can be an important cornerstone for many future research projects in various fields. More

Physicists were surprised by the 2022 discovery that electrons in magnetic iron-germanium crystals could spontaneously and collectively organize their charges into a pattern featuring a standing wave. Magnetism also arises from the collective self-organization of electron spins into ordered patterns, and those patterns rarely coexist with the patterns that produce the standing wave of electrons physicists call a charge density wave.
In a study published this week in Nature Physics, Rice University physicists Ming Yi and Pengcheng Dai, and many of their collaborators from the 2022 study, present an array of experimental evidence that shows their charge density wave discovery was rarer still, a case where the magnetic and electronic orders don’t simply coexist but are directly linked.
“We found magnetism subtly modifies the landscape of electron energy states in the material in a way that both promotes and prepares for the formation of the charge density wave,” said Yi, a co-corresponding author of the study.
The study was co-authored by more than a dozen researchers from Rice; Oak Ridge National Laboratory (ORNL); SLAC National Accelerator Laboratory; Lawrence Berkeley National Laboratory (LBNL); the University of Washington; the University of California, Berkeley; Israel’s Weizmann Institute of Science; and China’s Southern University of Science and Technology.
The iron-germanium materials are kagome lattice crystals, a much-studied family of materials featuring 2D arrangements of atoms reminiscent of the weave pattern in traditional Japanese kagome baskets, which features equilateral triangles that touch at the corners.
“Kagome materials have taken the quantum materials world by storm recently,” Yi said. “The cool thing about this structure is that the geometry imposes interesting quantum constraints on the way the electrons are allowed to zoom around, somewhat analogous to how traffic roundabouts affect the flow of traffic and sometimes bring it to a stop.”
By nature, electrons avoid one another. One way they do this is to order their magnetic states — spins that point either up or down — in the opposite direction of their neighbors’ spins.

Dai, a co-corresponding study author, said, “When put onto kagome lattices, electrons can also appear in a state where they are stuck and cannot go anywhere due to quantum interference effects.”
When electrons cannot move, the triangular arrangement produces a situation where each has three neighbors, and there is no way for electrons to collectively order all neighboring spins in opposite directions. The inherent frustration of electrons in Kagome lattice materials has long been recognized.
Yi said the lattice restricts electrons in ways that “can have a direct impact on the observable properties of the material,” and the team was able to use that “to probe deeper into the origins of the intertwinement of the magnetism and charge density wave” in iron-germanium.
They did so using a combination of inelastic neutron scattering experiments, which were performed at ORNL, and angle-resolved photoemission spectroscopy experiments that were performed at LBNL’s Advanced Light Source and SLAC’s Stanford Synchrotron Radiation Lightsource, as well in Yi’s lab at Rice.
“These probes allowed us to look at what both the electrons and the lattice were doing as the charge density wave was taking shape,” she said.

Dai said the findings confirmed the team’s hypothesis that charge order and magnetic order are linked in iron-germanium. “This is one of the very few, if not of the only, known example of a kagome material where magnetism forms first, preparing the way for charges to line up,” he said.
Yi said the work shows how curiosity and basic research into natural phenomena can eventually lead to applied science.
“As physicists, we are always excited when we find materials that spontaneously form an order of some sort,” she said. “This means there is a chance for us to learn about the self-organizational abilities of the fundamental particles of quantum materials. Only with that kind of understanding can we one day hope to engineer materials with novel or exotic properties that we can control at will.”
Dai is the Sam and Helen Worden Professor of Physics and Astronomy. Dai and Yi are each members of the Rice Quantum Initiative and the Rice Center for Quantum Materials (RCQM).
The research at Rice was supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative (GBMF9470), the Welch Foundation (C-2024, C-1839), the Department of Energy (DE-SC0021421) and the National Science Foundation (2100741, 1921847). More

Perovskites are materials that are increasingly popular for a wide range of applications because of their remarkable electrical, optical, and photonic properties. Perovskite materials have the potential to revolutionize the fields of solar energy, sensing and detecting, photocatalysis, lasers, and others.
The properties of perovskites can be tuned for specific applications by changing their chemical composition and internal architecture, including the distribution and orientation of its crystal structure. At the moment, the ability to influence these properties is massively limited by manufacturing methods. A team of scientists at TU Dresden was able to create perovskites with unique nano-architectures and crystal properties from algae, taking advantage of years of evolution of these single-celled organisms.
Taking Advantage of the Evolution
“Unicellular organisms have responded over hundreds of millions of years to a wide range of environmental factors such as temperature, pH, and mechanical stress. As a result, some of them evolved to produce absolutely unique biomaterials that are exclusive to nature,” says Dr. Igor Zlotnikov, research group leader at the B CUBE — Center for Molecular Bioengineering who led the study. “Minerals formed by living organisms often exhibit structural and crystallographic characteristics that are far beyond the production capacities offered by current synthetic methods.”
The team focused on L. granifera, a type of algae that uses calcite to form shells. Their spherical shells have a unique crystal architecture. The crystals are aligned radially which means that they spread out from the center of the sphere outwards. “The current manufacturing methods of perovskites are not able to produce materials like this synthetically. We can however try to transform the existing natural structures into functional materials while keeping their original architecture” adds Dr. Zlotnikov.
Chemical Tuning
To transform the natural mineral shells of algae into functional perovskites, the team had to substitute chemical elements in calcite. To do that, they adapted a method developed by their collaborators at AMOLF institute in Amsterdam. During the transformation, scientists were able to produce different types of crystal architectures by altering the chemical makeup of the material. In that way, they could fine-tune their electro-optical properties.

By converting the calcite shells to lead halides with either iodine, bromide, or chloride, the team could create functional perovskites that are optimized to emit only red, green, or blue light.
Ready for Scaling Up
“We show for the first time that minerals produced by single-cell organisms can be transformed into technologically relevant functional materials. Instead of competing with nature, we can take advantage of the years of evolutionary adaptation they already went through” says Dr. Zlotnikov.
The method developed by his team can be scaled up, opening up the possibility for the industry to take advantage of algae and numerous other calcite-forming single-celled organisms to produce functional materials with unique shapes and crystallographic properties.
Funding
The project was part of the DinoLight imitative supported by the Free State of Saxony to develop innovative, environmentally friendly materials and technologies based on naturally occurring three-dimensional nanostructures. More

The number of injuries in youth athletics is significantly reduced when coaches and parents have access to digital information on adolescent growth. It also takes twice as long for the first injury to occur. This is shown in a study from Linköping University published in the British Journal of Sports Medicine.
Many promising athletes have had their careers ruined because of injuries. One thing that almost all events in athletics have in common is a high load for a short time, as in jumping, throwing and running. This leads to overuse injuries such as groin pain and sore shoulders but also sudden injuries such as ankle sprain and hamstring tear.
Jenny Jacobsson is a physiotherapist and visiting researcher at the Athletics Research Center at Linköping University. She has worked as a medical coordinator for the Swedish national athletics team for many years and has seen the impact of injuries on athletes.
“Before the 2008 Beijing Olympics, we saw many injuries in our national team and tried to figure out why. At the time, no survey had been done of injury incidence in athletics athletes. But we wanted to find out what was happening among our elite athletes from age 16 and up, including adult elite athletes,” says Jenny Jacobsson.
The survey of injuries in Swedish athletics showed that one of the main causes of injury was prior injury. This means that the earlier an athlete is injured in their career, the higher the likelihood that they will be injured later and more frequently. But causes of injury in youth sports is a complex matter, associated with everything from training amount and load to equipment, and even sleep.
Together with her colleagues at the Athletics Research Center, Jenny Jacobsson has developed a digital health platform containing information for parents and youth coaches on adolescent growth and how this is affected by training, with a focus on athletics athletes aged 12-15.
To investigate whether this type of platform can prevent injuries, the researchers carried out a study where 21 athletics clubs with athletes aged 12-15 were randomised into two groups: an intervention group and a control group. For four months during the early season, the intervention group parents and coaches were given access to the digital information platform, which at the time was not open to outsiders (but is now open to anyone). They were also regularly encouraged to log in and explore its content.
The researchers noted that the clubs given access to the information showed significantly lower injury incidence and that it took twice as long for the first injury to occur. Moreover, the effect was greater in large clubs. The results, published in the British Journal of Sports Medicine, can point the way to more injury-free athletics.
“We haven’t investigated the mechanism leading to change, but we can see that digital information works when it comes to injury prevention. If coaches and parents learn to recognise the problems, it’s possible to reduce the training load in time. Medically we know what is happening in growing bodies, but getting the information out to those who can benefit from it has been a challenge. This platform may bridge that gap,” says Jenny Jacobsson.
The study was financed by the Swedish Research Council for Sport Science (Centrum för idrottsforskning). More

A ‘best practice’ protocol for researchers developing piezoelectric materials has been developed by scientists — a first in this cutting-edge field of technology.
The protocol was developed by an international team led by physicists at University of Bath in the UK, in response to findings that experimental reports lack consistency. The researchers made the shocking discovery that nine out of 10 scientific papers miss experimental information that is crucial to ensure the reproducibility of the reported work. They discuss the urgent need for a standardised piezoelectricity research protocol in the journal Nano Energy.
Dr Morteza Hassanpour Amiri at the Max Planck Institute for Polymer Research, Germany and first author of the study, said: “Research into piezoelectricity has accelerated in recent years, and for good reason: piezoelectric materials generate electricity when you exert pressure or mechanical vibrations, or when you tap on or distort them. Add a circuit and this electricity can be stored and then used.”
High energy-harvesting efficiency
Because of the huge potential of the piezoelectrics, over the past 20 years a steady stream of new materials and composites have been developed and tested for their energy harvesting potential, with many claiming high efficiencies.
But the researchers, led by Professor Kamal Asadi from the Department of Physics, suggest these findings — sometimes published in high-calibre journals — often do not include details of key experimental parameters. These details are essential to ensure reproducibility when other research teams set out to independently evaluate or further improve the featured materials.

Explaining, Professor Asadi said: “Reproducibility of experimental research findings may not be the key to the success of a research, but it is the key to ruling out unreliable findings from being accepted as fact. The enthusiasm to develop a champion material that shows impressive performance should be accompanied with enough supporting data.”
For the study, the Bath researchers assessed 80 randomly selected research papers published over the past two decades on piezoelectric energy harvesting devices. For nearly 90% of these papers, essential experimental parameters — needed to evaluate materials and devices — were missing, thus rendering the experiments hard, and sometimes impossible, to reproduce.
The importance of reproducibility
Expanding, Professor Asadi said: “There are three important reasons why reproducibility is important: We are scientists and should strive to be as accurate as possible; we have limited resources, so by reporting all the necessary parameters that guarantee reproducibility, we are helping our peers to build up on our findings and advance the field; by being transparent, we also build trust with the public, and with science funding organisations and policymakers, and provide a better guidance for future ‘big’ decisions that can affect us all.”
Professor Asadi, who is a leading expert in piezoelectricity, says this lack of data is hampering progress in the field, as researchers can’t turn to the literature to identify materials with the best harvesting potential, and then further develop these promising materials.

New protocol
The new Bath protocol suggests a standardised data collection and reporting. Professor Chris Bowen from the Department of Mechanical Engineering at Bath, who was also involved in this study, said: “We have basically created guidelines that would be helpful to researchers in their field of piezoelectricity.”
Professor Asadi is hopeful that electronic devices powered by piezoelectricity will be on the market within the next 10 years.
“That’s why it’s important to have a standardised protocol for reporting research data for a quantitative evaluation of energy harvesting materials and devices. Doing so enables scientists to make real progress building on each other’s experiments and working towards a common goal: making piezoelectricity a reality for anyone hoping to charge their devices more sustainably and without reliance on a traditional power source.”
He added: “The field of piezoelectric energy harvesting is a really exciting field, it has lots of potential and great scientists are working on it, but it’s still fledgling, and so to make sure we advance as well and as quickly as possible, ensuring experiments are reproducible is going to be crucial, so I hope our suggested protocol is adopted by the community at large.”
The new protocol is described in the paper “Piezoelectric energy harvesters: A critical assessment and a standardized reporting of power-producing vibrational harvesters.” More