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New imaging technique uses Earth’s warped surface to reveal rocky interior

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New imaging technique uses Earth’s warped surface to reveal rocky interior


New imaging technique uses earth's warped surface to reveal rocky interior
A graphic showing the stiffness of Earth’s crust beneath Japan. The image reveals the boundary where Japan’s continental plate (large dark red patch) collides with the stiffer oceanic plate (dark blue patch). The smaller dark red patches in the center of the image are likely a magma system feeding Japan’s volcanoes (red triangles). The image was created using data collected with a new deformation imaging technique developed by researchers at UT Austin. Credit: Simone Puel

Surface mapping technology such as GPS, radar and laser scanning have long been used to measure features on the Earth’s surface. Now, a new computational technique developed at The University of Texas at Austin is allowing scientists to use those technologies to look inside the planet.

The new technique, described by researchers as “deformation imaging,” provides results comparable to seismic imaging but offers direct information about the rigidity of the planet’s crust and mantle. This property is essential for understanding how earthquakes and other large-scale geological processes work, said Simone Puel, who developed the method for a research project at the University of Texas Institute for Geophysics while in graduate school at the UT Jackson School of Geosciences.

“Material properties like rigidity are critical to understand the different processes that occur in a subduction zone or in earthquake science in general,” Puel said.

“When combined with other techniques like seismic, electromagnetic or gravity, it should be possible to actually produce a much more comprehensive mechanical model of an earthquake in a way that has never been done before.”

Puel, who is now a postdoctoral scholar at the California Institute of Technology, published the theory behind his method in Geophysical Journal International earlier this year. A recent study published in June in Science Advances shows it in action. It used GPS data recorded during Japan’s 2011 Tohoku earthquake to image the subsurface down to about 100 kilometers underground.

The image revealed the tectonic plates and volcanic system beneath the Japanese portion of the Pacific Ring of Fire, including an area of low rigidity that’s thought to be a deep magma reservoir feeding the system—the first time such a reservoir has been detected using only surface information.

New imaging technique uses earth's warped surface to reveal rocky interior
A GPS station atop the Sierra Nevada mountains. UT Austin researchers used GPS networks to image the planet’s interior. Credit: UNAVCO/NSF

The method relies on the fact that Earth’s crust is a hodge-podge of rocky material with differing elastic properties. Some parts are more pliant, and other parts are more rigid. This causes the crust to contract and expand unevenly. During an earthquake, for example, the Earth vibrates in a way that reflects what it’s made of, leaving the surface deformed in telltale ways.

To turn this uneven deformation into an image of the subsurface, the researchers constructed a computer model that treats the Earth as if it is a simplified elastic material, while allowing its elastic strength to vary in three dimensions.

The model then computed the subsurface rigidity based on how much the GPS sensors had moved in relation to one another during the earthquake. The result is a 3D picture of the Earth’s interior based on changes on the surface.

An advantage of the new method is that it can use measurements made by satellites. These include NASA’s upcoming NISAR spacecraft, a joint mission with the Indian Space Research Organization that will map the entire globe in very high resolution every 12 days.

Using the new technique, NISAR could offer important insights into some of the world’s most geologically hazardous regions, said study co-author Thorsten Becker, a professor at the Jackson School. By continuously mapping the Earth’s surface, the satellite will allow scientists to track structural changes in earthquake faults as they progress through their earthquake cycle.

Co-author Omar Ghattas, a professor at the UT Walker Department of Mechanical Engineering and UT Oden Institute for Computational Engineering and Sciences, said that the new method could be an important step to building digital twins of the Earth. These complex computer models perpetually improve themselves by identifying where to make new observations, then assimilating the new data.

More information:
S Puel et al, An adjoint-based optimization method for jointly inverting heterogeneous material properties and fault slip from earthquake surface deformation data, Geophysical Journal International (2023). DOI: 10.1093/gji/ggad442

Simone Puel et al, Volcanic arc rigidity variations illuminated by coseismic deformation of the 2011 Tohoku-oki M9, Science Advances (2024). DOI: 10.1126/sciadv.adl4264

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New imaging technique uses Earth’s warped surface to reveal rocky interior (2024, July 2)
retrieved 2 July 2024
from https://phys.org/news/2024-07-imaging-technique-earth-warped-surface.html

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New understanding of a common plant enzyme could lead to better crop management

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New understanding of a common plant enzyme could lead to better crop management


New understanding of a common plant enzyme could lead to better crop management
Visual representations of the chitinase surface and secondary structures. Credit: U.S. Department of Energy, Ames National Laboratory

New findings about chitinases, enzymes found naturally in plants, could allow farmers to address fungal infections sooner and more efficiently.

Researchers from the U.S. Department of Energy Ames National Laboratory investigated chitinases from corn and rice to better understand their roles in indicating if a plant is under stress and combating fungal attacks. Their findings suggest that these enzymes could be a valuable resource not only for monitoring crop health overall, but also for optimizing biomass for use in alternative energy sources.

Two of the most important agricultural crops worldwide are corn and rice. In addition to providing food, both have important energy applications as well through the use of their waste plant matter, or biomass, from crop harvesting. Corn is a major crop used to create biofuel, while rice husks are used for heating, electricity, and biofuel.

One major threat to crop yields comes from pathogens such as fungi, bacteria, and viruses. Fungi alone cause a 35%–40% yield loss in corn and rice crops each year.

“There’s a lot of interest in chitinases in the plant world because of their general occurrence and their involvement in protecting plants from fungal attacks” explained Marit Nilsen-Hamilton, a scientist at Ames Lab and leader of the research team. “Chitinases are really important to plants for protection.”

Much of Nilsen-Hamilton’s work is focused primarily on the rhizosphere, a narrow zone of soil around plant roots where intense microbial activity takes place. Roots in the soil release many substances, including sugars and chitinases, as well as polymers that hold everything together. Bacteria in the soil also contribute to these excretions, and the polymers they release form a very thin film over the plant roots.

“In the rhizosphere, the plants secrete sugar to attract the bacteria, because they want those rhizobacteria to be around and to help them out. Plants feed the bacteria and the bacteria feed and protect the plants,” Nilsen-Hamilton said. “Still, there are these fungal infections and when the plants are under stress it will cause them to release chitinases.”

Her team chose specific chitinases recommended by their collaborating plant biochemist, Olga Zabotina, that are released by the plants in response to fungal attack. Their first step was gaining a full understanding of the enzymes’ functional and molecular characteristics.

“Very little has been done with chitinases in general in terms of the purification and characterization,” Nilsen-Hamilton explained. “So, my graduate student Samuel Shobade undertook the job of characterizing them.”

The team wanted to know whether these chitinases are a good indicator of fungi-related plant stress, and whether they could kill fungi. They found that one of the chitinases was effective at killing the Aspergillus niger fungi, which can cause black mold in a variety of agricultural crops.

In addition to characterizing the chitinases, the team also wanted to know if any would be good receptors for aptamers. “Aptamers are nucleic acids that behave like antibodies, but you don’t need an animal to make them. In fact, you make them in a test tube,” Nilsen-Hamilton explained.

Aptamers can be used to detect chitinases and could potentially be used to activate certain chitinases that are secreted in response to fungal infections. The chitinase from the rice proved to be a bad target for aptamers, because both the enzyme and the aptamer protein are negatively charged, so they repelled each other. However, the corn chitinase turned out to be a good aptamer receptor.

This research also helps Nilsen-Hamilton’s work on using nucleic acid aptamers to detect fungal disease early before it is too late for the plant’s survival.

“Our engineering collaborator, Pranav Shrotriya, has developed a way of using nucleic acid aptamers to detect molecules by using what’s called an electrochemical device. And the probe can be made so small that it can be put down into the soil. So that gives us the opportunity to detect things in the soil that plant roots make, that bacteria make, etc.,” she said.

Characterizing these chitinases has been an important contribution to her team’s work towards being able to detect these proteins released by the plants. The ability to detect them early can allow farmers to intervene early, when the infection can be more easily resolved.

Understanding the chitinases can also lead to more targeted treatments than applying a general fungicide or intervening when plants finally look stressed. The findings could have economic impact not only on traditional agricultural crops and their waste biomass for energy production, but also on dedicated energy crops—those grown specifically to create biomass for fuel.

This research is further discussed in “Plant root associated chitinases: structures and functions,” written by Samuel O. Shobade, Olga A. Zabotina, and Marit Nilsen-Hamilton, and published in Frontiers in Plant Science.

More information:
Samuel O. Shobade et al, Plant root associated chitinases: structures and functions, Frontiers in Plant Science (2024). DOI: 10.3389/fpls.2024.1344142

Citation:
New understanding of a common plant enzyme could lead to better crop management (2024, July 2)
retrieved 2 July 2024
from https://phys.org/news/2024-07-common-enzyme-crop.html

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Regulation needed to curb favoritism between countries and credit rating agencies, new research suggests

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Regulation needed to curb favoritism between countries and credit rating agencies, new research suggests


business man
Credit: Pixabay/CC0 Public Domain

A country’s financial health is rated more highly when its finance minister knows top executives in credit ratings agencies, new research led by Heriot-Watt University in Edinburgh suggests.

Patrycja Klusak, an expert in credit ratings agencies and Professor of Accounting and Finance at the University’s Edinburgh Business School, says there is an inherent ‘favoritism’ problem in the business model of credit ratings agencies. This builds up when the directors and executives of credit ratings agencies have ongoing or past professional connections with particular finance ministers. For example, when a ratings agency executive and finance minister worked together in the same organization, or are former colleagues.

Countries where a finance minister has these links are associated with higher ratings than countries without these professional connections, the research concludes. The upside is particularly pronounced for developing countries, which can be rated up to seven times more highly than the equivalent impact for developed countries.

The findings are based on an analysis of professional connections between finance ministers and the top executives of the three largest credit rating agencies—Fitch, Moody’s, and S&P—for 38 European countries between January 2000 and November 2017.

The research, “Politicians’ connections and sovereign credit ratings”, is published in the Journal of International Financial Markets, Institutions & Money and is co-authored by Dr. Yurtsev Uymaz, Associate Professor in Finance with Norwich Business School at University of East Anglia and Rasha Alsakka, Professor in Banking & Finance with Bangor Business School at Bangor University.

“The ratings applied to a country’s financial health are hugely important because they help that country—and its banks and businesses—to access capital and borrow money at affordable rates,” Professor Klusak explains. “They also underpin direct investment flows into big national projects and affect the efficiency and stability of capital markets across borders.

“If ratings agencies are consciously or unconsciously inflating their ratings of particular countries, it’s a problem, because for financial markets to work properly, buyers of government debt need to know the true creditworthiness of that country.”

The European sovereign debt crisis of 2010–12 exposed the risk of excessive national borrowing fueling a collapse in confidence that can spill over into other countries and their corporations, banks and financial assets, Professor Klusak says.

The crisis began with the collapse of Iceland’s banking system in 2008 and led to financial bailouts in Greece, Spain, Ireland, Portugal and Cyprus. “Drastic sovereign rating downgrades” in Portugal, Italy, Ireland, Greece, and Spain were key to this and “shook the stock markets,” the research notes.

European regulators scrutinized ratings agencies in the aftermath of this crisis, particularly the conflict of interest when countries pay agencies to rate them, and get a seat on ratings agency committees as a result.

This practice, known as solicited ratings, leads to higher ratings than unsolicited ratings, the research finds. Issuing higher ratings may help the ratings agency attract more business from that country, while countries in turn are safeguarding the health of their economy through higher ratings.

Professor Klusak says the research is the first to unveil how lower credit ratings for developing countries can be influenced by credit agencies using ‘soft’ information—for example, a discussion with the country about its financial prospects and management policies—in addition to hard economic or fiscal data, such as gross domestic product.

“Developing countries can be more uncertain and opaque, with less available data,” Professor Klusak explains. “So ratings agencies need to be more conservative in their analysis. But, when presented with professional connections, these nations benefit more from higher ratings than their developed counterparts.”

The research finds that, for developed countries, business ties to ratings agencies can add roughly between one to two-thirds of a notch—classification—to their ratings across S&P, Moody’s and Fitch. For developing countries, the boost is seven-, two- and four-times bigger respectively than the equivalent for developed countries.

The research has “wide-ranging implications” for regulators, governments, market participants and credit rating agencies, Professor Klusak says. During election times, voters are also more interested in news about a country’s financial health, because it “infers the quality of incumbent governments,” she adds.

The paper calls for new rules to ensure that sovereign ratings—credit ratings of countries—are objective and independent from the rating of other asset types, like corporate loans, to avoid conflicts of interest.

Working conditions for sovereign ratings teams should also be improved—because these teams face “immense pressure” to release ratings which might bring in other business from that country—for example from its corporations and financial institutions, the researchers say.

The study contributes towards the “scarce literature” investigating professional connections in the rating industry, the researchers conclude.

Professor Klusak has been researching the behavior and regulation of credit ratings agencies for more than ten years. Her work also explores climate and biodiversity loss and its effect on future credit ratings of countries.

Before joining Heriot-Watt University, Dr. Klusak was an Associate Professor in Banking and Finance with Norwich Business School at the University of East Anglia, where she has been based for eight years. Professor Klusak is also an Affiliated Researcher at the Bennett Institute for Public Policy, a public policy research institute at the University of Cambridge.

More information:
Patrycja Klusak et al, Politicians’ connections and sovereign credit ratings, Journal of International Financial Markets, Institutions and Money (2024). DOI: 10.1016/j.intfin.2024.102022

Citation:
Regulation needed to curb favoritism between countries and credit rating agencies, new research suggests (2024, July 2)
retrieved 2 July 2024
from https://phys.org/news/2024-07-curb-favoritism-countries-credit-agencies.html

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part may be reproduced without the written permission. The content is provided for information purposes only.





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Researchers demonstrate second-generation digital display with perovskite light-emitting diodes

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Researchers demonstrate second-generation digital display with perovskite light-emitting diodes


Researchers demonstrate second-generation digital display with perovskite light-emitting diodes
Structure of AM PeLED. a, Micrograph of one single pixel in the TFT backplane showing the layout of TFT and LED area. b, The schematic diagram shows the control of LED by the 3T1C circuit. c, Structure diagram of the drive TFT and LED. d, e Cross-sectional scanning electron microscope (SEM) images of the drive TFT and ITO. Credit: Nature Electronics (2024). DOI: 10.1038/s41928-024-01181-5

A team of microelectronic engineers affiliated with several institutions in China, working with a colleague from Sweden, has demonstrated a second-generation digital display screen that uses perovskite light-emitting diodes instead of standard LED technology.

In their study, published in the journal Nature Electronics, the group made improvements to the device and demonstrated its sensing capability.

In April, a research team with some of the same members demonstrated a digital display screen using LEDs made out of perovskite instead of semiconductor compounds such as gallium, arsenide or indium gallium nitride. They also showed that such screens could be used as sensing devices.

For this new study, the researchers also built a digital display device using perovskite light-emitting diode (PeLED) technology—this one with double the pixel resolution.

Current materials used to make LEDs have attributes including a high degree of acuity and sharpness. But the technology had limitations, such as an inability to serve as a sensor—other components have been used to fill the gap.

To overcome that limitation, researchers have been looking at perovskite, because in addition to emitting light, it can also absorb it, allowing it to be used as a sensing device. If a phone had PeLEDs, the screen would be able to sense touch, a fingerprint or even ambient light, mitigating the need for other components.

Researchers demonstrate second-generation digital display with perovskite light-emitting diodes
One-inch AM PeLEDs with a resolution of 90 PPI (pixel size 270 μm × 270 μm). a–c, Digital photographs of the red (a), green (b) and blue (c) emissive AM PeLEDs showing cartoon pictures. d–f, EL spectra of the red (d), green (e) and blue (f) emissive AM PeLEDs at various Vdd driving voltages, displaying a single peak with narrow full-width at half-maximum (FWHM). g–i, Transient EL intensities of red (g), green (h) and blue (i) emissive AM PeLEDs under various pulse durations. Credit: Nature Electronics (2024). DOI: 10.1038/s41928-024-01181-5

The new screen demonstrated by the research team had a 90 ppi density—a far cry from the densities of current smartphone screens, but a step toward equivalence. It also demonstrated a host of sensing abilities. The researchers believe such displays will also have much longer lifecycles and use less energy.

On the downside, researchers have had to contend with stability—exposing PeLEDs to oxygen or moisture leads to degradation, an issue that will have to be solved before such technology could be used in commercial devices.

More information:
Yun Gao et al, Microsecond-response perovskite light-emitting diodes for active-matrix displays, Nature Electronics (2024). DOI: 10.1038/s41928-024-01181-5

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Researchers demonstrate second-generation digital display with perovskite light-emitting diodes (2024, July 2)
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Watching others’ biased behavior unconsciously creates prejudice, finds study

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Watching others’ biased behavior unconsciously creates prejudice, finds study


peephole
Credit: Unsplash/CC0 Public Domain

We unconsciously form prejudice toward groups when we see biased people interact with members of a group. That is according to new research by psychologists of the University of Amsterdam (UvA), who show for the first time that observational learning is an important mechanism of prejudice formation. Their results were published in Science Advances.

David Amodio (UvA) says, “What we found in our research is that prejudice can form by merely observing other people’s social interactions. When an observer views a prejudiced person’s interaction with a group member, they unconsciously form the same prejudice. Moreover, because observers are unaware that they picked up this bias, they go on to act with prejudice in their own behavior.”

This mechanism helps to explain how societal prejudices spread so easily, for example, through the viewing of TV programs, YouTube or other social media where biased interactions with certain groups take place. By merely observing those interactions, vicariously and with no direct contact, people may take on the same prejudices.

During the experiments, a research participant viewed interactions between an actor and members of two different groups. Across participants, the actor varied in prejudice, but the behavior of group members was always identical.

When observers later interacted with the same group members, observers showed a preference in line with the actor’s prejudice. Moreover, observers were unaware that they were influenced by the prejudiced actor; instead, they misperceived worse behavior from group members who interacted with a prejudiced actor, when in fact, members of both groups acted the same.

Amodio says, “A troubling implication is that, because the observer believes that their preference is based on objective evidence, they have no reason to question it or control it.”

More information:
David T. Schultner et al, Transmission of social bias through observational learning, Science Advances (2024). DOI: 10.1126/sciadv.adk2030

Citation:
Watching others’ biased behavior unconsciously creates prejudice, finds study (2024, July 2)
retrieved 2 July 2024
from https://phys.org/news/2024-07-biased-behavior-unconsciously-prejudice.html

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part may be reproduced without the written permission. The content is provided for information purposes only.





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