. Scientific Frontline

Wednesday, April 27, 2022

Glim­pse inside a gra­phene sand­wich

Honeycomb-shaped structures made of carbon atoms, known as graphene, can conduct electric current without resistance when twisted against each other.
Credit: Uni Innsbruck

In the search for novel types of superconductors – phases of matter that conduct electric current without loss – scientists are investigating materials that consist of multiple layers. A team led by theoretical physicist Mathias Scheurer has studied in detail the properties of a system of three twisted graphene layers and gained important insights into its properties.

Since the first successful fabrication of a two-dimensional structure of carbon atoms about 20 years ago, graphene has fascinated scientists. A few years ago, researchers discovered that two layers of graphene, slightly twisted against each other, can conduct electric current without loss. In recent years, this discovery has prompted scientists to explore such layered materials in greater detail. A recent notable example is mirror-symmetric twisted trilayer graphene, where three layers of graphene are stacked with alternating twist angles. It is the first moiré system that can both be efficiently tuned with a perpendicular electric field and was demonstrated experimentally to exhibit robust superconductivity, alongside various other phases. “This establishes trilayer graphene as an exciting platform for complex many-body physics, but the nature of the observed interaction-induced insulators, semi-metals, and superconductivity remains unknown”, says Mathias Scheurer from the Department of Theoretical Physics of the University of Innsbruck.

Monday, April 25, 2022

Study Reveals Diminished Role for Neutrons in Creation of Carbon in Stars

The Texas Active Target (TexAT) particle detector designed and built by Texas A&M physicists is the centerpiece in a collaborative experiment to test whether other particles — specifically stray neutrons — could be involved in creating carbon.
Credit: Rogachev Group

A Texas A&M University-led collaboration has yielded new insight into one of the universe’s most important primordial reactions that made all life on Earth possible.

The multi-institution team of nuclear scientists that also includes researchers from Washington University in St. Louis and Ohio University concluded in a recent study that the role neutrons play in the creation of carbon, considered the definitive building block of life, actually is much smaller than previously thought.

Their data, acquired during 2020 and analyzed within the past year, is detailed in a paper published in Nature Communications.

“These findings are extremely significant because it demonstrates that the rate at which stars burn helium together to form carbon is less sensitive to any neutrons in the stars, which were previously thought to speed up this process,” said Dr. Jack Bishop, an assistant research scientist at the Texas A&M Cyclotron Institute and a lead author of the paper. “Understanding the way that stars burn is extremely important in understanding the life and death of stars, as well as where the elements that make up our universe originate from and in what quantity.”

Scientists discover promising biologic drug for treating chronic lung disease

Associate Professor Ge Ruowen (left) from NUS Biological Sciences and Professor Fred Wong (right) of NUS Pharmacology.
Credit: National University of Singapore

NUS scientists have discovered a novel property of a protein found in human lungs which could lead to the development of biologic drugs to treat chronic obstructive pulmonary disease (COPD), a debilitating, progressive lung disease that is one of the leading causes of death worldwide.

The research was led by Associate Professor Ge Ruowen from NUS Biological Sciences and published in the prestigious scientific journal Proceedings of the National Academy of Sciences.

Fighting COPD

COPD is currently the third-leading cause of death globally and poses a large socioeconomic burden on nations. It can be caused by long-term exposure to irritants or particulate matter, such as cigarette smoke, and symptoms include coughing, breathing difficulties, mucus production and wheezing.

Patients with COPD display two key conditions - emphysema (the destruction of alveolar walls and enlargement of the alveoli) and chronic obstructive bronchitis (inflamed small airways). These patients suffer persistent respiratory symptoms with progressive long-term lung function decline. However, current drugs targeting COPD only provide symptomatic relief and are not able to suppress the underlying tissue inflammation to effectively block the spread of COPD or reduce mortality.

“COPD patients have difficulty breathing which hinders their ability to work or exercise. They do not absorb enough oxygen, and this affects their heart function too. COPD is a very dangerous condition, but public awareness of it is very low,” said Assoc Prof Ge.

The destructive power of language

Hate expressions can take many forms - they can also be very subtle in the field of language.
Credit: Roberto Schirdewahn

Artificial intelligence can well identify swear words. But it can also recognize more hidden forms of linguistic violence?

"Piss off, you bitch!"" I'll get the bum. I'll stab you."" You should all pop them off. "Just a few examples of the form that language can take on social media. People are insulted, threatened or incited to crime. Prof. is interested in what distinguishes hate speech and other forms of damaging language from a linguistic perspective and how you can automatically recognize them. Dr. Tatjana Scheffler. She conducts research at the RUB in the field of digital forensic linguistics.

"Language processing in general has made big leaps in recent years," says Scheffler. Anyone who uses translation programs such as Google Translator or language assistants such as Siri today will achieve significantly better results than a few years ago. The classification of texts is now working quite well. Artificial intelligence algorithms can learn to assign statements to different categories. For example, you can decide whether a text passage contains a direct insult or not. The algorithms learn the categories using large training data sets that people have previously classified. Later they can transfer the knowledge of the learned categories to new data.

Sunday, April 17, 2022

Fermilab is home to a new baby bison!

This year, Fermilab is expecting up to 20 new calves.
Credit: Ryan Postel, Fermilab

World-class particle physics research isn’t the only thing Fermilab is known for. The iconic sight of the Midwestern bison graces the acres of prairie land surrounding the lab, beckoning visitors from across the country. On April 13, baby bison season officially began at the lab, a sure sign spring is truly on its way. The first calf of the year was born in the morning, and we’re pleased to announce that both mother and baby are doing well.

 Currently, the herd comprises 32 bison — 30 females and two bulls. The bulls are changed out periodically to maintain the herd’s health and genetic diversity.

This year, Fermilab is expecting up to 20 new calves. For a front-seat view of the bison, visit Fermilab’s new bison cam to glimpse the activities of the mighty herd.

Robert Wilson, Fermilab’s first director, established the bison herd in 1969 as a symbol of the history of the Midwestern prairie and the laboratory’s pioneering research at the cutting-edge of particle physics.

Study finds an unexpected upside to imposter syndrome

People who report “impostor workplace thoughts” are often still successful, by being strong team players in the office, and being recognized as such, according to a new study. The research was led by MIT Sloan Assistant Professor Basima Tewfik.
Credit: MIT

Even many successful people harbor what is commonly called impostor syndrome, a sense of being secretly unworthy and not as capable as others think. First posited by psychologists in 1978, it is often assumed to be a debilitating problem.

But research by an MIT scholar suggests this is not universally true. In workplace settings, at least, those harboring impostor-type concerns tend to compensate for their perceived shortcomings by being good team players with strong social skills, and are often recognized as productive workers by their employers.

“People who have workplace impostor thoughts become more other-oriented as a result of having these thoughts,” says Basima Tewfik, an assistant professor at the MIT Sloan School of Management and author of a new paper detailing her findings. “As they become more other-oriented, they’re going to be evaluated as being more interpersonally effective.”

Tewfik’s research as a whole suggests we should rethink some of our assumptions about impostor-type complexes and their dynamics. At the same time, she emphasizes, the prevalence of these types of thoughts among workers should not be ignored, dismissed, or even encouraged.

Putting Tried-and-True Theories to the Test

Assistant Professor of Physics Katerina Chatziioannou
Source: California Institute of Technology

Albert Einstein's general theory of relativity is a triumph of science, celebrated by scientists around the world for, among other truths, explaining how gravity works. Whereas Isaac Newton proposed in the late 17th century that gravity is a force tugging on objects, Einstein taught us, in the early 20th century, that gravity is in fact a warping of space and time. The more massive an object, the more it curves space and produces stronger gravity.

Now, many decades later, scientists are using a prediction of Einstein's general theory of relativity—gravitational waves—to study the universe and to even poke holes in the theory itself. Einstein predicted these ripples in spacetime 100 years ago but they were not directly detected until 2015, when the National Science Foundation-funded LIGO (Laser Interferometer Gravitational-wave Observatory) detected the waves from a collision between two black holes.

Assistant Professor of Physics Katerina Chatziioannou, who joined the Caltech faculty in 2020 and is part of the LIGO team, is using gravitational waves to explore these extreme events. She is using the waves to study the space-bending objects themselves, such as black holes and neutron stars, as well as to look for places where our current knowledge of gravity might break down. Any deviations from the tried-and-true theory could lead to new discoveries in physics.

Saturday, April 16, 2022

Stroke cuts life expectancy by one third

Almost two thirds of acute stroke patients fail to survive more than a decade and have high risk of recurrence, prompting researchers to call for better patient care.

University of Queensland researchers analyzed data from more than 300,000 patients admitted to hospital following a sudden stroke between 2008 and 2017 in Australia and New Zealand.

The team also investigated how many years were lost to stroke by comparing a patient’s predicted life expectancy with the length of actual survival.

Study leader and UQ epidemiologist, Dr Yang Peng, a Research Fellow with the Prince Charles Hospital Northside Clinical Unit, said only 36.4 per cent of patients survived beyond 10 years, and 26.8 per cent had another stroke.

“We found that a stroke reduced a patient’s life expectancy by five and a half years on average, compared with the general population,” Dr Peng said.

“In proportional terms, this meant a stroke reduced a person’s life expectancy by one third.

“Patients with a hemorrhagic stroke who have bleeding in the brain are at greater risk of death, another stroke and reduced life expectancy, than those with an ischemic stroke, which is caused by a burst blood vessel.”

Acute stroke is one of the most common causes of hospitalization and disability in Australia and has been linked to risk factors such as high blood pressure, elevated cholesterol levels, diabetes, smoking and heart disease by the Stroke Foundation.

Nationwide maps of bird species can help protect biodiversity

Researchers mapped the number of bird species found across the contiguous U.S. Blue areas host fewer bird species than green or yellow areas do. 
Images by Kathleen Carroll and Anna Pidgeon

New, highly detailed and rigorous maps of bird biodiversity could help protect rare or threatened species.

Researchers at the University of Wisconsin–Madison developed the maps at a fine-enough resolution to help conservation managers focus their efforts where they are most likely to help birds — in individual counties or forests, rather than across whole states or regions.

The maps span the contiguous U.S. and predict the diversity of birds that live in a given area, related by traits such as nesting on the ground or being endangered. Those predictions are based on both detailed observations of birds and environmental factors that affect bird ranges, such as the degree of forest cover or temperature in an area.

Changes in vegetation shaped global temperatures over last 10,000 years

Alexander Thompson, a postdoctoral research associate in earth and planetary sciences in Arts & Sciences, updated simulations from an important climate model to reflect the role of changing vegetation as a key driver of global temperatures over the last 10,000 years.
Source: Washington University in St. Louis

Follow the pollen. Records from past plant life tell the real story of global temperatures, according to research from a climate scientist at Washington University in St. Louis.

Warmer temperatures brought plants — and then came even warmer temperatures, according to new model simulations published in Science Advances.

Thompson had long been troubled by a problem with models of Earth’s atmospheric temperatures since the last ice age. Too many of these simulations showed temperatures warming consistently over time.

But climate proxy records tell a different story. Many of those sources indicate a marked peak in global temperatures that occurred between 6,000 and 9,000 years ago.

Thompson had a hunch that the models could be overlooking the role of changes in vegetation in favor of impacts from atmospheric carbon dioxide concentrations or ice cover.

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