Understanding of invisible but mighty particles in Earth's radiation belts

Tiny charged electrons and protons which can damage satellites and alter the ozone have revealed some of their mysteries to University of Otago scientists.

In a study, published in Geophysical Research Letters, the group looked at charged particles interacting with a type of radio wave called 'EMIC' -- a wave generated in Earth's radiation belts (invisible rings of charged particles orbiting the Earth).

Lead author Dr Aaron Hendry, of the Department of Physics, says it is important to understand how these waves affect the belts -- which are filled with expensive and important satellites -- and Earth's climate.

"Much like the Earth's atmosphere, the Earth's magnetosphere -- the region around the Earth where our magnetic field is stronger than the Sun's -- sometimes experiences strong 'storms', or periods of high activity. These storms can cause significant changes to the number of particles in the radiation belts and can accelerate some of them to very high speeds, making them a danger to our satellites. Knowing how many of these particles there are, as well as how fast they're moving, is very important to us, so that we can make sure our satellites keep working.

"Activity within the radiation belts can sometimes cause the orbits of these particles to change. If these changes bring the particles low enough to reach the Earth's upper atmosphere, they can hit the dense air, lose all of their energy and fall out of orbit.

"EMIC waves are known to be able to cause these changes and drive the loss of particles from the radiation belts. As well as causing beautiful light displays that we call aurora, this rain of particles can also cause complex chemical changes to the upper atmosphere that can in turn cause small, but important, changes the amount of ozone present in atmosphere.

"Although these changes are small, understanding them is very important to properly understanding how the chemistry of the atmosphere works, how it is changing over time, and the impact it is having on the climate," Dr Hendry says.

For their latest study, the researchers used data from GPS satellites to look at how many electrons EMIC waves can knock into the Earth's atmosphere.

A general rule in the radiation belts is that at slower speeds, you have many more electrons. So, if the minimum speed of the EMIC wave interaction is lowered, there are a lot more electrons around to interact with waves.

By looking at data from satellites that monitor how many electrons there are in the radiation belts and how fast they're going, the researchers have been able to show that you can see the number of electrons in the radiation belts go down significantly when EMIC waves are around.

"Excitingly, we have also seen changes in the number of electrons at speeds significantly lower than the current 'accepted' minimum speed. This means that EMIC can affect much larger numbers of electrons than we previously thought possible. Clearly, we need to rethink how we're modelling this interaction, and the impact it has on the radiation belts. There are a lot of electrons in the radiation belts, so being able to knock enough of them into the atmosphere to make a noticeable change is quite remarkable.

"This has shown that we need to take these EMIC waves into account when we're thinking about how the radiation belts change over time, and how these changes in the radiation belt affect the climate on Earth."

Dr Hendry says the impact of EMIC-driven electrons on atmospheric chemistry is not currently being included by major climate models, which try to predict how the Earth's climate will change over time, so making sure this process is understood and included in these models is very important.

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New tool activates deep brain neurons by combining ultrasound, genetics

Neurological disorders such as Parkinson's disease and epilepsy have had some treatment success with deep brain stimulation, but those require surgical device implantation. A multidisciplinary team at Washington University in St. Louis has developed a new brain stimulation technique using focused ultrasound that is able to turn specific types of neurons in the brain on and off and precisely control motor activity without surgical device implantation.

The team, led by Hong Chen, assistant professor of biomedical engineering in the McKelvey School of Engineering and of radiation oncology at the School of Medicine, is the first to provide direct evidence showing noninvasive, cell-type-specific activation of neurons in the brain of mammal by combining ultrasound-induced heating effect and genetics, which they have named sonothermogenetics. It is also the first work to show that the ultrasound- genetics combination can robustly control behavior by stimulating a specific target deep in the brain.

Results of the three years of research, which was funded in part by the National Institutes of Health's BRAIN Initiative, were published online in Brain Stimulation May 11, 2021.

The senior research team included experts from both the McKelvey School of Engineering and the School of Medicine, including Jianmin Cui, professor of biomedical engineering; Joseph P. Culver, professor of radiology, of physics and of biomedical engineering; Mark J. Miller, associate professor of medicine in the Division of Infectious Diseases in the Department of Medicine; and Michael Bruchas, formerly of Washington University, now professor of anesthesiology and pharmacology at the University of Washington.

"Our work provided evidence that sonothermogenetics evokes behavioral responses in freely moving mice while targeting a deep brain site," Chen said. "Sonothermogenetics has the potential to transform our approaches for neuroscience research and uncover new methods to understand and treat human brain disorders."

Using a mouse model, Chen and the team delivered a viral construct containing TRPV1 ion channels to genetically-selected neurons. Then, they delivered small burst of heat via low-intensity focused ultrasound to the select neurons in the brain via a wearable device. The heat, only a few degrees warmer than body temperature, activated the TRPV1 ion channel, which acted as a switch to turn the neurons on or off.

"We can move the ultrasound device worn on the head of free-moving mice around to target different locations in the whole brain," said Yaoheng Yang, first author of the paper and a graduate student in biomedical engineering. "Because it is noninvasive, this technique has the potential to be scaled up to large animals and potentially humans in the future."

The work builds on research conducted in Cui's lab that was published in Scientific Reports in 2016. Cui and his team found for the first time that ultrasound alone can influence ion channel activity and could lead to new and noninvasive ways to control the activity of specific cells. In their work, they found that focused ultrasound modulated the currents flowing through the ion channels on average by up to 23%, depending on channel and stimulus intensity. Following this work, researchers found close to 10 ion channels with this capability, but all of them are mechanosensitive, not thermosensitive.

The work also builds on the concept of optogenetics, the combination of the targeted expression of light-sensitive ion channels and the precise delivery of light to stimulate neurons deep in the brain. While optogenetics has increased discovery of new neural circuits, it is limited in penetration depth due to light scattering and requires surgical implantation of optical fibers.

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Astronomer reveals never-before-seen detail of the center of our galaxy

New research by University of Massachusetts Amherst astronomer Daniel Wang reveals, with unprecedented clarity, details of violent phenomena in the center of our galaxy. The images, published recently in Monthly Notices of the Royal Astronomical Society, document an X-ray thread, G0.17-0.41, which hints at a previously unknown interstellar mechanism that may govern the energy flow and potentially the evolution of the Milky Way.

"The galaxy is like an ecosystem," says Wang, a professor in UMass Amherst's astronomy department, whose findings are a result of more than two decades of research. "We know the centers of galaxies are where the action is and play an enormous role in their evolution." And yet, whatever has happened in the center of our own galaxy is hard to study, despite its relative proximity to Earth, because, as Wang explains, it is obscured by a dense fog of gas and dust. Researchers simply can't see the center, even with an instrument as powerful as the famous Hubble Space Telescope. Wang, however, has used a different telescope, NASA's Chandra X-Ray Observatory, which "sees" X-rays, rather than the rays of visible light that we perceive with our own eyes. These X-rays are capable of penetrating the obscuring fog -- and the results are stunning.

Wang's findings, which were supported by NASA, give the clearest picture yet of a pair of X-ray-emitting plumes that are emerging from the region near the massive black hole lying at the center of our galaxy. Even more intriguing is the discovery of an X-ray thread called G0.17-0.41, located near the southern plume. "This thread reveals a new phenomenon," says Wang. "This is evidence of an ongoing magnetic field reconnection event." The thread, writes Wang, probably represents "only the tip of the reconnection iceberg."

A magnetic field reconnection event is what happens when two opposing magnetic fields are forced together and combine with one another, releasing an enormous amount of energy. "It's a violent process," says Wang, and is known to be responsible for such well-known phenomena as solar flares, which produce space weather powerful enough to disrupt power grids and communications systems here on Earth. They also produce the spectacular Northern Lights. Scientists now think that magnetic reconnection also occurs in interstellar space and tends to take place at the outer boundaries of the expanding plumes driven out of our galaxy's center.

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Gravitational wave search no hum drum hunt

The hunt for the never before heard "hum" of gravitational waves caused by mysterious neutron stars has just got a lot easier, thanks to an international team of researchers.

Gravitational waves have only been detected from black holes and neutron stars colliding, major cosmic events that cause huge bursts that ripple through space and time.

The research team, involving scientists from the LIGO Scientific Collaboration (LSC), Virgo Collaboration and the Centre for Gravitational Astrophysics (CGA) at The Australian National University (ANU), are now turning their eagle eye to spinning neutron stars to detect the waves.

Unlike the massive bursts caused by black holes or neutron stars colliding, the researchers say single spinning neutron stars have a bulge or "mountain" only a few millimetres high, which may produce a steady constant stream or "hum" of gravitational waves.

The researchers are using their methods that detected gravitational waves for the first time in 2015 to capture this steady soundtrack of the stars over the thunderous noise of massive black holes and dense neutron stars colliding.

They say it's like trying to capture the squeak of a mouse in the middle of a stampeding herd of elephants.

If successful, it would be the first detection of a gravitational wave event that didn't involve the collision of massive objects like black holes or neutron stars.

ANU Distinguished Professor, Susan Scott from the ANU Research School of Physics, said the collision of dense neutron stars sent a "burst" of gravitational waves rippling through the Universe.

"Neutron stars are mystery objects," Professor Scott, also a Chief Investigator with the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), said.

"We don't really understand what they are made up of, or how many types of them exist. But what we do know is that when they collide, they send incredible bursts of gravitational waves across the Universe.

"In contrast, the gentle hum of a spinning neutron star is very faint and almost impossible to detect."

Three new papers have just been published by the LSC and Virgo collaborations detailing the most sensitive searches to date for the faint hum of gravitational waves from spinning neutron stars.

Their work offers a "map to the potential El Dorado of gravitational waves."

"One of our searches targets young supernova remnants. These neutron stars, recently born, are more deformed, and should emit a stronger stream of gravitational waves," Dr Lilli Sun, from CGA and an Associate Investigator with OzGrav, said.

As these searches become more and more sensitive they are providing more detail than ever of the possible shape and make-up of neutron stars.

"If we can manage to detect this hum, we'll be able to look deep into the heart of a neutron star and unlock its secrets," Dr Karl Wette, a postdoctoral researcher with OzGrav and the CGA, said.

Professor Scott, who is also the leader of the General Relativity Theory and Data Analysis Group at ANU, added: "Neutron stars represent the densest form of matter in the Universe before a black hole will form."

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Exoskeleton-assisted walking may improve bowel function in people with spinal cord injury

A team of researchers has shown that physical intervention plans that included exoskeleton-assisted walking helped people with spinal cord injury evacuate more efficiently and improved the consistency of their stool.

The authors of the new article in Journal of Clinical Medicine are Peter H. Gorman, MD, of the University of Maryland School of Medicine, Gail F. Forrest, PhD, of Kessler Foundation's Tim and Caroline Reynolds Center for Spinal Stimulation, Dr. William Scott, of VA Maryland Healthcare System, Pierre K. Asselin, MS, Stephen Kornfeld, MD, Eunkyoung Hong, PhD, and Ann M. Spungen, EdD, of the James J. Peters VA Medical Center.

Bowel dysfunction, a common experience after spinal cord injury, can lead to chronic constipation and incontinence, causing discomfort and frustration. In one survey, more than a third of men with spinal cord injury reported that bowel and bladder dysfunction had the most significant effect on their lives post-injury. Unfortunately, these issues are not easily managed.

Rehabilitation professionals have traditionally managed bowel dysfunction using approaches that target the gastrointestinal system or require manual intervention, but some newer research suggests that physical activity and upright posture may enhance bowel motility. However, few studies have explored the possibility that exoskeletal-assisted walking -- in which a person with spinal cord injury wears a robotic suit, enabling them to stand and walk -- may be an effective addition to existing intervention plans.

In this study, the research team investigated whether exoskeletal-assisted walking improved bowel function in people with chronic spinal cord injury. They performed a three-center, randomized, controlled, crossover clinical trial in which 50 participants completed 36 sessions of exoskeletal-assisted walking. The researchers evaluated bowel function as a secondary outcome in 49 participants. Bowel function was measured via a 10-question bowel function survey, the Bristol Stool Form Scale, and the Spinal Cord Injury Quality of Life Bowel Management Difficulties instrument.

Results showed that the exoskeletal-assisted walking program provided some improvement in bowel function when compared to a control group. "We saw a notable reduction in bowel evacuation time, with 24 percent of participants reporting an improved experience," said Dr. Forrest, co-author and associate director of the Center for Mobility and Rehabilitation Engineering Research at Kessler Foundation. "We also noted that participants' stools trended toward better consistency, supporting our hypothesis that this intervention may improve several measures of bowel function."

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Biologists construct a 'periodic table' for cell nuclei

One hundred fifty years ago, Dmitri Mendeleev created the periodic table, a system for classifying atoms based on the properties of their nuclei. This week, a team of biologists studying the tree of life has unveiled a new classification system for cell nuclei and discovered a method for transmuting one type of cell nucleus into another.

The study, which appears this week in the journal Science, emerged from several once-separate efforts. One of these centered on the DNA Zoo, an international consortium spanning dozens of institutions including Baylor College of Medicine, the National Science Foundation-supported Center for Theoretical Biological Physics (CTBP) at Rice University, the University of Western Australia and SeaWorld.

Scientists on the DNA Zoo team had been working together to classify how chromosomes, which can be several meters long, fold up to fit inside the nuclei of different species from across the tree of life.

"Whether we were looking at worms or urchins, sea squirts or coral, we kept seeing the same folding patterns coming up," said Dr. Olga Dudchenko, co-first author of the new study and a member of the Center for Genome Architecture at Baylor and CTBP.

Eventually, the team realized it was just seeing variants on two overall nuclear designs. "In some species, chromosomes are organized like the pages of a printed newspaper, with the outer margins on one side and the folded middle at the other," explained Dudchenko, who also is co-director of DNA Zoo. "And then in other species, each chromosome is crumpled into a little ball."

"So we had a puzzle," said Dr. Erez Lieberman Aiden, an associate professor of molecular and human genetics and Emeritus McNair Scholar at Baylor, co-director of the DNA Zoo and senior author on the new study. "The data implied that over the course of evolution, species can switch back and forth from one type to the other. We wondered: What is the controlling mechanism? Might it be possible to change one type of nucleus into another in the lab?" Aiden also is director of the Center for Genome Architecture and a senior investigator at CTBP.

Meanwhile, an independent team in the Netherlands had discovered something unexpected. "I was doing experiments on a protein called condensin II, which we knew plays a role in how cells divide," said Claire Hoencamp, co-first author of the study and a member of the laboratory of Dr. Benjamin Rowland at the Netherlands Cancer Institute. "But we observed the strangest thing: When we mutated the protein in human cells, the chromosomes would totally rearrange. It was baffling!"

The two teams met at a conference in the Austrian mountains, where Rowland presented his lab's latest work. They soon realized that Hoencamp had hit on a way to convert human cells from one nuclear type to another.

"When we looked at the genomes being studied at the DNA Zoo, we discovered that evolution had already done our experiment many, many times! When mutations in a species break condensin II, they usually flip the whole architecture of the nucleus," said Rowland, senior author on the study. "It's always a little disappointing to get scooped on an experiment, but evolution had a very long head start."

The team decided to work together to confirm condensin II's role. But then the COVID-19 pandemic struck, and much of the world shut down.

"Without access to our laboratories, we were left with only one way to establish what condensin II was doing," Hoencamp said. "We needed to create a computer program that could simulate the effects of condensin II on the chain of hundreds of millions of genetic letters that comprise each human chromosome."

The team turned to Dr. José Onuchic, the Harry C. and Olga K. Wiess Chair of Physics at Rice. "Our simulations showed that by destroying condensin II, you could make a human nucleus reorganize to resemble a fly nucleus," said Onuchic, co-director of CTBP, which includes collaborators at Rice, Baylor, Northeastern University and other institutions in Houston and Boston.

The simulations were performed by a team within Onuchic's lab at CTBP, led by postdoctoral fellow and co-first author Dr. Sumitabha Brahmachari, working with Dr. Vinicius Contessoto, a former postdoc at CTBP, and Dr. Michele Di Pierro, a CTBP senior investigator and currently an assistant professor at Northeastern University.

"We began with an incredibly broad survey of 2 billion years of nuclear evolution," Brahmachari said. "And we found that so much boils down to one simple mechanism, that we can simulate as well as recapitulate, on our own, in a test tube. It's an exciting step on the road to a new kind of genome engineering -- in 3D!"

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Dark matter map reveals hidden bridges between galaxies

A new map of dark matter in the local universe reveals several previously undiscovered filamentary structures connecting galaxies. The map, developed using machine learning by an international team including a Penn State astrophysicist, could enable studies about the nature of dark matter as well as about the history and future of our local universe.

Dark matter is an elusive substance that makes up 80% of the universe. It also provides the skeleton for what cosmologists call the cosmic web, the large-scale structure of the universe that, due to its gravitational influence, dictates the motion of galaxies and other cosmic material. However, the distribution of local dark matter is currently unknown because it cannot be measured directly. Researchers must instead infer its distribution based on its gravitational influence on other objects in the universe, like galaxies.

"Ironically, it's easier to study the distribution of dark matter much further away because it reflects the very distant past, which is much less complex," said Donghui Jeong, associate professor of astronomy and astrophysics at Penn State and a corresponding author of the study. "Over time, as the large-scale structure of the universe has grown, the complexity of the universe has increased, so it is inherently harder to make measurements about dark matter locally."

Previous attempts to map the cosmic web started with a model of the early universe and then simulated the evolution of the model over billions of years. However, this method is computationally intensive and so far has not been able to produce results detailed enough to see the local universe. In the new study, the researchers took a completely different approach, using machine learning to build a model that uses information about the distribution and motion of galaxies to predict the distribution of dark matter.

The researchers built and trained their model using a large set of galaxy simulations, called Illustris-TNG, which includes galaxies, gasses, other visible matter, as well as dark matter. The team specifically selected simulated galaxies comparable to those in the Milky Way and ultimately identified which properties of galaxies are needed to predict the dark matter distribution.

"When given certain information, the model can essentially fill in the gaps based on what it has looked at before," said Jeong. "The map from our models doesn't perfectly fit the simulation data, but we can still reconstruct very detailed structures. We found that including the motion of galaxies -- their radial peculiar velocities -- in addition to their distribution drastically enhanced the quality of the map and allowed us to see these details."

The research team then applied their model to real data from the local universe from the Cosmicflow-3 galaxy catalog. The catalog contains comprehensive data about the distribution and movement of more than 17 thousand galaxies in the vicinity of the Milky Way -- within 200 megaparsecs. The resulting map of the local cosmic web is published in a paper appearing online May 26 in the Astrophysical Journal.

The map successively reproduced known prominent structures in the local universe, including the "local sheet" -- a region of space containing the Milky Way, nearby galaxies in the "local group," and galaxies in the Virgo cluster -- and the "local void" -- a relatively empty region of space next to the local group. Additionally, it identified several new structures that require further investigation, including smaller filamentary structures that connect galaxies.

"Having a local map of the cosmic web opens up a new chapter of cosmological study," said Jeong. "We can study how the distribution of dark matter relates to other emission data, which will help us understand the nature of dark matter. And we can study these filamentary structures directly, these hidden bridges between galaxies."

For example, it has been suggested that the Milky Way and Andromeda galaxies may be slowly moving toward each other, but whether they may collide in many billions of years remains unclear. Studying the dark matter filaments connecting the two galaxies could provide important insights into their future.

"Because dark matter dominates the dynamics of the universe, it basically determines our fate," said Jeong. "So we can ask a computer to evolve the map for billions of years to see what will happen in the local universe. And we can evolve the model back in time to understand the history of our cosmic neighborhood."

The researchers believe they can improve the accuracy of their map by adding more galaxies. Planned astronomical surveys, for example using the James Web Space Telescope, could allow them to add faint or small galaxies that have yet to be observed and galaxies that are further away.

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Deep oceans dissolve the rocky shell of water-ice planets

 What is happening deep beneath the surface of ice planets? Is there liquid water, and if so, how does it interact with the planetary rocky "seafloor"? New experiments show that on water-ice planets between the size of our Earth and up to six times this size, water selectively leaches magnesium from typical rock minerals. The conditions with pressures of hundred thousand atmospheres and temperatures above one thousand degrees Celsius were recreated in a lab and mimicked planets similar, but smaller than Neptune and Uranus.

The mechanisms of water-rock interaction at the Earth's surface are well known, and the picture of the complex cycle of H2O in the deep interior of our and other terrestrial planets is constantly improving. However, we do not know what happens at the interface between hot, dense H2O and the deep rocky shell of water-ice planets at pressures and temperatures orders of magnitude higher than at the bottom of the deepest oceans on Earth. In the solar system Neptune and Uranus are classified as ice-giants; they have a thick external water-ice layer, which is underlain by a deep rocky layer, and it is still discussed whether the temperature at the interface is high enough to form liquid water.

An international research team lead by Taehyun Kim of the Yonsei University of Seoul, Korea, including scientists from the University of Arizona, from DESY, from Argonne National Laboratory, and Sergio Speziale of the GFZ German Research Centre for Geosciences, conducted a series of challenging experiments both at PETRA III (Hamburg) and the Advanced Photon Source (Argonne, U.S.A.) showing how water strongly leaches magnesium oxide (MgO) from certain minerals, i.e. ferropericlase (Mg,Fe)O and olivine (Mg,Fe)2SiO4 at pressures between 20 and 40 Gigapascal (GPa). This equals 200,000 to 400,000 times the atmospheric pressure on Earth and temperatures above 1500 K (? 1230 °C), conditions which are present at the interface between deep oceans and the rocky mantle in sub-Neptune class of water planets. Sergio Speziale says: "These findings open new scenarios for the thermal history of large icy planets such as Neptune and Uranus." The results of this study are published in the scientific journal Nature Astronomy.

Tiny pellets of either ferropericlase or olivine powder were loaded together with water in a tiny sample chamber (less than a millimetre in diameter) drilled in a metal foil and squeezed between two gem-quality diamonds culets using a diamond anvil cell (DAC). The samples were heated by shining an infrared laser through the diamond anvils. Synchrotron x-ray diffraction was used to determine minerals transformation and breakdown induced by reactions with water. A sudden decrease of diffraction signal from the starting minerals, and the appearance of new solid phases including brucite (magnesium hydroxide) were observed across full heating and quenching cycles. Sergio Speziale explains: "This demonstrated the onset of chemical reactions and the dissolution of the magnesium oxide component of both ferropericlase and olivine; the dissolution was strongest in a specific pressure-temperature range between 20 to 40 Gigapascal and 1250 to 2000 Kelvin." The details of the reaction process and the consequent chemical segregation of MgO from the residual phases, were confirmed by thorough Scanning Electron Microscopy (SEM) and X-ray spectroscopy of the recovered samples. "At these extreme pressures and temperatures the solubility of magnesium oxide in water reaches levels similar to that of salt at ambient conditions," Sergio Speziale says.

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Banning the sale of fossil-fuel cars benefits the climate when replaced by electric cars

If a ban were introduced on the sale of new petrol and diesel cars, and they were replaced by electric cars, the result would be a great reduction in carbon dioxide emissions. That is the finding of new research from Chalmers University of Technology, Sweden, looking at emissions from the entire life cycle -- from manufacture of electric cars and batteries, to electricity used for operation. However, the total effect of a phasing out of fossil-fuelled cars will not be felt until the middle of the century -- and how the batteries are manufactured will affect the extent of the benefit.

A rapid and mandatory phasing in of electric cars could cause emissions from Swedish passenger cars' exhausts to approach zero by 2045. The Swedish government has proposed an outright ban on the sale of new fossil fuel cars from the year 2030 -- but that alone will not be enough to achieve Sweden's climate targets on schedule.

"The lifespan of the cars currently on the roads and those which would be sold before the introduction of such a restriction mean that it would take some time -- around 20 years -- before the full effect becomes visible," says Johannes Morfeldt, researcher in Physical Resource Theory at Chalmers University of Technology and lead author of the recently published scientific study.

To have the desired effect, a ban would either need to be introduced earlier, by the year 2025, or, if the ban is not brought in until 2030, then the use of biofuels in petrol and diesel cars needs to increase significantly before then -- in accordance with the revised Swedish "reduction obligation." The combination of these two measures would have the effect of achieving zero emissions from passenger vehicles and keeping to Sweden's climate targets.

"The results from our study show that rapid electrification of the Swedish car fleet would reduce life cycle emissions, from 14 million tonnes of carbon dioxide in 2020 to between 3 and 5 million tonnes by the year 2045. The end result in 2045 will depend mainly on the extent to which possible emission reductions in the manufacturing industry are realised," says Johannes Morfeldt.

A transition from petrol and diesel cars to electric cars will mean an increased demand for batteries. Batteries for electric cars are often criticised, not least for the fact that they result in high levels of greenhouse gas emissions during manufacture.

"There are relatively good opportunities to reduce emissions from global battery manufacturing. Our review of the literature on this shows that average emissions from global battery manufacturing could decrease by about two thirds per kilowatt hour of battery capacity by the year 2045. However, most battery manufacturing takes place overseas, so Swedish decision-makers have more limited opportunities to influence this question," says Johannes Morfeldt.

From a climate perspective, it does not matter where the emissions take place, and the risk with decisions taken at a national level for lowering passenger-vehicle emissions is that they could lead to increased emissions elsewhere -- a phenomenon sometimes termed 'carbon leakage'. In this case, the increase in emissions would result from greater demand for batteries, and the risk is thus greater the higher the emissions from battery production.

In that case, the Swedish decision would not have as great an effect on reducing the climate impact as desired. The life-cycle emissions would end up in the upper range -- around 5 million tonnes of carbon dioxide instead of around 3 million tonnes. Due to this, there may be reason to regulate emissions in both vehicle and battery production, from a life cycle perspective.

"Within the EU, for example, there is a discussion about setting a common standard for the manufacture of batteries and vehicles -- in a similar way as there is a standard that regulates what may be emitted from exhausts," says Johannes Morfeldt.

But, given Sweden's low emissions from electricity production, a ban on sales of new fossil-fuel cars would indeed result in a sharp reduction of the total climate impact, regardless of how the manufacturing industry develops.

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Amazon indigenous group's lifestyle may hold a key to slowing down aging

A team of international researchers has found that the Tsimane indigenous people of the Bolivian Amazon experience less brain atrophy than their American and European peers. The decrease in their brain volumes with age is 70% slower than in Western populations. Accelerated brain volume loss can be a sign of dementia.

The study was published May 26, 2021 in the Journal of Gerontology, Series A: Biological Sciences and Medical Sciences.

Although people in industrialized nations have access to modern medical care, they are more sedentary and eat a diet high in saturated fats. In contrast, the Tsimane have little or no access to health care but are extremely physically active and consume a high-fiber diet that includes vegetables, fish and lean meat.

"The Tsimane have provided us with an amazing natural experiment on the potentially detrimental effects of modern lifestyles on our health," said study author Andrei Irimia, an assistant professor of gerontology, neuroscience and biomedical engineering at the USC Leonard Davis School of Gerontology and the USC Viterbi School of Engineering. "These findings suggest that brain atrophy may be slowed substantially by the same lifestyle factors associated with very low risk of heart disease."

The researchers enrolled 746 Tsimane adults, ages 40 to 94, in their study. To acquire brain scans, they provided transportation for the participants from their remote villages to Trinidad, Bolivia, the closest town with CT scanning equipment. That journey could last as long as two full days with travel by river and road.

The team used the scans to calculate brain volumes and then examined their association with age for Tsimane. Next, they compared these results to those in three industrialized populations in the U.S. and Europe.

The scientists found that the difference in brain volumes between middle age and old age is 70% smaller in Tsimane than in Western populations. This suggests that the Tsimane's brains likely experience far less brain atrophy than Westerners as they age; atrophy is correlated with risk of cognitive impairment, functional decline and dementia.

The researchers note that the Tsimane have high levels of inflammation, which is typically associated with brain atrophy in Westerners. But their study suggests that high inflammation does not have a pronounced effect upon Tsimane brains.

According to the study authors, the Tsimane's low cardiovascular risks may outweigh their infection-driven inflammatory risk, raising new questions about the causes of dementia. One possible reason is that, in Westerners, inflammation is associated with obesity and metabolic causes whereas, in the Tsimane, it is driven by respiratory, gastrointestinal, and parasitic infections. Infectious diseases are the most prominent cause of death among the Tsimane.

"Our sedentary lifestyle and diet rich in sugars and fats may be accelerating the loss of brain tissue with age and making us more vulnerable to diseases such as Alzheimer's," said study author Hillard Kaplan, a professor of health economics and anthropology at Chapman University who has studied the Tsimane for nearly two decades. "The Tsimane can serve as a baseline for healthy brain aging."

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New details on what happened in the first microsecond of Big Bang

About 14 billion years ago, our universe changed from being a lot hotter and denser to expanding radically -- a process that scientists have named 'The Big Bang'.

And even though we know that this fast expansion created particles, atoms, stars, galaxies and life as we know it today, the details of how it all happened are still unknown.

Now a new study performed by researchers from University of Copenhagen reveals insights on how it all began.

"We have studied a substance called Quark-Gluon Plasma that was the only matter, which existed during the first microsecond of Big Bang. Our results tell us a unique story of how the plasma evolved in the early stage of the universe," explains You Zhou, Associate Professor at the Niels Bohr Institute, University of Copenhagen.

"First the plasma that consisted of quarks and gluons was separated by the hot expansion of the universe. Then the pieces of quark reformed into so-called hadrons. A hadron with three quarks makes a proton, which is part of atomic cores. These cores are the building blocks that constitutes earth, ourselves and the universe that surrounds us," he adds.

From fluent and smooth to the strong building blocks of life

The Quark-Gluon Plasma (QGP) was present in the first 0.000001 second of Big Bang and thereafter it disappeared because of the expansion.

But by using the Large Hadron Collider at CERN, researchers were able to recreate this first matter in history and trace back what happened to it.

"The collider smashes together ions from the plasma with great velocity -- almost like the speed of light. This makes us able to see how the QGP evolved from being its own matter to the cores in atoms and the building blocks of life," says You Zhou.

"In addition to using the Large Hadron Collider, the researches also developed an algorithm that is able to analyze the collective expansion of more produced particles at once, than ever possible before. Their results show that the QGP used to be a fluent liquid form and that it distinguishes itself from other matters by constantly changing its shape over time.

"For a long time researchers thought that the plasma was a form of gas, but our analysis confirm the latest milestone measurement, where the Hadron Collider showed that QGP was fluent and had a smooth soft texture like water. The new details we provide is that the plasma has changed its shape over time, which is quite surprising and different from any other matter we know and what we would have expected," says You Zhou.

One step closer to the truth about Big Bang

Even though this might seem like a small detail, it brings us one step closer to solving the puzzle of the Big Bang and how the universe developed in the first microsecond, he elaborates.

"Every discovery is a brick that improves our chances of finding out the truth about Big Bang. It has taken us about 20 years to find out that the Quark-Gluon Plasma was fluent before it changed into hadrons and the building blocks of life. Therefore our new knowledge on the ever changing behavior of the plasma, is a major breakthrough for us," You Zhou concludes.

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Don't count on caffeine to fight sleep deprivation

Rough night of sleep? Relying on caffeine to get you through the day isn't always the answer, says a new study from Michigan State University.

Researchers from MSU's Sleep and Learning Lab, led by psychology associate professor Kimberly Fenn, assessed how effective caffeine was in counteracting the negative effects of sleep deprivation on cognition. As it turns out, caffeine can only get you so far.

The study -- published in the most recent edition of Journal of Experimental Psychology: Learning, Memory, & Cognition -- assessed the impact of caffeine after a night of sleep deprivation. More than 275 participants were asked to complete a simple attention task as well as a more challenging "placekeeping" task that required completion of tasks in a specific order without skipping or repeating steps.

Fenn's study is the first to investigate the effect of caffeine on placekeeping after a period of sleep deprivation.

"We found that sleep deprivation impaired performance on both types of tasks and that having caffeine helped people successfully achieve the easier task. However, it had little effect on performance on the placekeeping task for most participants," Fenn said.

She added: "Caffeine may improve the ability to stay awake and attend to a task, but it doesn't do much to prevent the sort of procedural errors that can cause things like medical mistakes and car accidents."

Insufficient sleep is pervasive in the United States, a problem that has intensified during the pandemic, Fenn said. Consistently lacking adequate sleep not only affects cognition and alters mood, but can eventually take a toll on immunity.

"Caffeine increases energy, reduces sleepiness and can even improve mood, but it absolutely does not replace a full night of sleep, Fenn said. "Although people may feel as if they can combat sleep deprivation with caffeine, their performance on higher-level tasks will likely still be impaired. This is one of the reasons why sleep deprivation can be so dangerous."

Fenn said that the study has the potential to inform both theory and practice.

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Electric fish -- and humans -- pause before communicating key points

American writer and humorist Mark Twain, a master of language and noted lecturer, once offered, "The right word may be effective, but no word was ever as effective as a rightly timed pause."

Electric fish and today's TED talk speakers take a page from Twain's playbook. They pause before sharing something particularly meaningful. Pauses also prime the sensory systems to receive new and important information, according to research from Washington University in St. Louis.

"There is an increased response in listeners to words -- or in this case, electrical pulses -- that happens right after a pause," said Bruce Carlson, professor of biology in Arts & Sciences and corresponding author of the study published May 26 in Current Biology. "Fish are basically doing the same thing we do to communicate effectively."

Beyond discovering interesting parallels between human language and electric communication in fish, the research reveals an underlying mechanism for how pauses allow neurons in the midbrain to recover from stimulation.

Carlson and collaborators, including first author Tsunehiko Kohashi, formerly a postdoctoral research associate at Washington University, conducted their study with electric fish called mormyrids. These fish use weak electric discharges, or pulses, to locate prey and to communicate with one another.

The scientists tracked the banter between fish housed under different conditions. They observed that electric fish that were alone in their tanks tend to hum along without stopping very much, producing fewer and shorter pauses in electric output than fish housed in pairs. What's more, fish tended to produce high frequency bursts of pulses right after they paused.

The scientists then tried an experiment where they inserted artificial pauses into ongoing communication between two fish. They found that the fish receiving a pause -- the listeners -- increased their own rates of electric signaling just after the artificially inserted pauses. This result indicates that pauses were meaningful to the listeners.

Other researchers have studied the behavioral significance of pauses in human speech. Human listeners tend to recognize words better after pauses, and effective speakers tend to insert pauses right before something that they want to have a significant impact.

"Human auditory systems respond more strongly to words that come right after a pause, and during normal, everyday conversations, we tend to pause just before speaking words with especially high-information content," Carlson said. "We see parallels in our fish where they respond more strongly to electrosensory stimuli that come after a pause. We also find that fish tend to pause right before they produce a high-frequency burst of electric pulses, which carries a large amount of information."

The scientists wanted to understand the underlying neural mechanism that causes these effects. They applied stimulation to electrosensory neurons in the midbrain of the electric fish and observed that continually stimulated neurons produced weaker and weaker responses. This progressive weakness is referred to as short-term synaptic depression.

Cue Mark Twain and his well-timed pauses.

The scientists inserted pauses into the continuous stimulation. They found that pauses as short as about one second allowed the synapses to recover from short-term depression and increased the response of the postsynaptic neurons to stimuli following the pause.

"Pauses inserted in electric speech reset the sensitivity of the listener's brain, which was depressed during the continuous part of the speech," Kohashi said. "Pauses seem to make the following message as clear as possible for the listener."

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Hundreds of antibiotic resistant genes found in the gastrointestinal tracts of Danish infants

Hundreds of antibiotic resistant genes found in the gastrointestinal tracts of Danish infants.

Danish one-year-olds carry several hundred antibiotic resistant genes in their bacterial gut flora according to a new study from the University of Copenhagen. The presence of these genes is partly attributable to antibiotic use among mothers during pregnancy.

An estimated 700,000 people die every year from antibiotic resistant bacterial infections and diseases. The WHO expects this figure to multiply greatly in coming decades. To study how antibiotic resistance occurs in humans' natural bacterial flora, researchers from the University of Copenhagen's Department of Biology analysed stool samples from 662 Danish one-year-old children.

Within the samples, the researchers discovered 409 different genes, providing bacteria with resistance to 34 types of antibiotics. Furthermore, 167 of the 409 genes found are resistant to multiple types of antibiotics, including those classified as 'critically important' by the WHO for being able to treat serious diseases in the future.

"It's a wake-up call that one-year-old children are already carrying gut bacteria that are resistant to very important types of antibiotics. New resistant bacteria are becoming more widespread due to increased antibiotic consumption. The horror scenario is that we will one day lack the antibiotics needed to treat life-threatening bacterial infections such as pneumonia or foodborne illnesses," explains Department of Biology professor Søren Sørensen, who led the study.

Antibiotic use during pregnancy is an important factor

The important factor for whether an infant had more antibiotic-resistant genes in bacteria in the gut was if the child's mother had been administered antibiotics during late pregnancy or if the year-old infant had received antibiotics in the months prior to the collection of their stool samples.

"We found a very strong correlation between a mother's antibiotic treatment during late pregnancy and of infants and gut bacteria with many resistant genes, although it appears that other influences come into play as well," says Xuan Ji Li of the Department of Biology, the study's lead author.

At the same time, the researchers found a link between how well-developed the gut flora of children were and the concentration of resistant bacteria. Well-developed gut flora equated with a lesser incidence of resistant bacteria. Previous studies from the same group of children demonstrated that the development of gut flora is linked to asthma risk later in life.

E. coli collect resistant genes

Escherichia coli (E. coli) is common in the intestine and can lead to intestinal infections. But in this study, the researchers also learned that E. coli appears to act as a main collector and a potential spreader of antibiotic-resistant genes to other gut bacteria.

The researchers also found E. coli in infants with high concentrations of resistance genes in their intestinal tracts.

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Does the Milky Way move like a spinning top?

An investigation carried out by the astrophysicists of the Instituto de Astrofísica de Canarias (IAC) Zofia Chrobáková, a doctoral student at the IAC and the University of La Laguna (ULL), and Martín López Corredoira, questions one of the most interesting findings about the dynamics of the Milky Way in recent years: that the precession, or the wobble in the axis of rotation of the disc warp is incorrect. The results have just been published in The Astrophysical Journal.

The Milky Way is a spiral galaxy, which means that it is composed, among other components, of a disc of stars, gas and dust, in which the spiral arms are contained. At first, it was thought that the disc was completely flat, but for some decades now it is known that the outermost part of the disc is distorted into what is called a "warp": in one direction it is twisted upwards, and in the opposite direction downwards. The stars, the gas, and the dust are all warped, and so are not in the same plane as the extended inner part of the disc, and an axis perpendicular to the planes of the warp defines their rotation.

In 2020, an investigation announced the detection of the precession of the warp of the Milky Way disc, which means that the deformation in this outer region is not static, but that just like a spinning top the orientation of its axis is itself rotating with time. Furthermore, these researchers found that it was quicker than the theories predicted, a cycle every 600-700 million years, some three times the time it takes the Sun to travel once round the centre of the Galaxy.

Precession is not a phenomenon which occurs only in galaxies, it also happens to our planet. As well as its annual revolution around the Sun, and its rotation period of 24 hours, the axis of the Earth precesses, which implies that the celestial pole is not always close to the present pole star, but that (as an example) 14,000 years ago it was close to the star Vega.

Now, a new study by Zofia Chrobáková and Martín López Corredoira has taken into account the variation of the amplitude of the warp with the ages of the stars. The study concludes that, using the warp of the old stars whose velocities have been measured, it is possible that the precession can disappear, or at least become slower than what is presently believed. To arrive at this result the researchers have used data from the Gaia Mission of the European Space Agency (ESA), analysing the positions and velocities of hundreds of millions of stars in the outer disc.

"In previous studies it had not been noticed," explains Zofia Chrobáková, a predoctoral researcher at the IAC and the first author of the article, "that the stars which are a few tens of millions of years old, such as the Cepheids, have a much larger warp than that of the stars visible with the Gaia mission, which are thousands of millions of years old."

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Milky Way not unusual, astronomers find

The first detailed cross-section of a galaxy broadly similar to the Milky Way, published today, reveals that our galaxy evolved gradually, instead of being the result of a violent mash-up. The finding throws the origin story of our home into doubt.

The galaxy, dubbed UGC 10738, turns out to have distinct 'thick' and 'thin' discs similar to those of the Milky Way. This suggests, contrary to previous theories, that such structures are not the result of a rare long-ago collision with a smaller galaxy. They appear to be the product of more peaceful change.

And that is a game-changer. It means that our spiral galaxy home isn't the product of a freak accident. Instead, it is typical.

The finding was made by a team led by Nicholas Scott and Jesse van de Sande, from Australia's ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) and the University of Sydney.

"Our observations indicate that the Milky Way's thin and thick discs didn't come about because of a gigantic mash-up, but a sort-of 'default' path of galaxy formation and evolution," said Dr Scott.

"From these results we think galaxies with the Milky Way's particular structures and properties could be described as the 'normal' ones."

This conclusion -- published in The Astrophysical Journal Letters- has two profound implications.

"It was thought that the Milky Way's thin and thick discs formed after a rare violent merger, and so probably wouldn't be found in other spiral galaxies," said Dr Scott.

"Our research shows that's probably wrong, and it evolved 'naturally' without catastrophic interventions. This means Milky Way-type galaxies are probably very common.

"It also means we can use existing very detailed observations of the Milky Way as tools to better analyse much more distant galaxies which, for obvious reasons, we can't see as well."

The research shows that UGC 10738, like the Milky Way, has a thick disc consisting mainly of ancient stars -- identified by their low ratio of iron to hydrogen and helium. Its thin disc stars are more recent and contain more metal.

(The Sun is a thin disc star and comprises about 1.5% elements heavier than helium. Thick disc stars have three to 10 times less.)

Although such discs have been previously observed in other galaxies, it was impossible to tell whether they hosted the same type of star distribution -- and therefore similar origins. Scott, van de Sande and colleagues solved this problem by using the European Southern Observatory's Very Large Telescope in Chile to observe UGC 10738, situated 320 million light years away.

The galaxy is angled "edge on," so looking at it offered effectively a cross-section of its structure.

"Using an instrument called the multi-unit spectroscopic explorer, or MUSE, we were able to assess the metal ratios of the stars in its thick and thin discs," explained Dr van de Sande.

"They were pretty much the same as those in the Milky Way -- ancient stars in the thick disc, younger stars in the thin one. We're looking at some other galaxies to make sure, but that's pretty strong evidence that the two galaxies evolved in the same way."

Dr Scott said UGC 10738's edge-on orientation meant it was simple to see which type of stars were in each disc.

"It's a bit like telling apart short people from tall people," he said. "It you try to do it from overhead it's impossible, but it if you look from the side it's relatively easy."

Co-author Professor Ken Freeman from the Australian National University said, "This is an important step forward in understanding how disk galaxies assembled long ago. We know a lot about how the Milky Way formed, but there was always the worry that the Milky Way is not a typical spiral galaxy. Now we can see that the Milky Way's formation is fairly typical of how other disk galaxies were assembled."

ASTRO 3D director, Professor Lisa Kewley, added: "This work shows how the Milky Way fits into the much bigger puzzle of how spiral galaxies formed across 13 billion years of cosmic time."

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Press (re)play to remember - How the brain strengthens memories during sleep

While we sleep, the brain produces particular activation patterns. When two of these patterns -- slow oscillations and sleep spindles -- gear into each other, previous experiences are reactivated. The stronger the reactivation, the clearer will be our recall of past events, a new study reveals.

Scientists have long known that slow oscillations (SOs) and sleep spindles -- sudden half-second to two-second bursts of oscillatory brain activity -- play an important role in the formation and retention of new memories.

But experts in the UK and Germany have discovered that the precise combination of SOs and sleep spindles is vital for opening windows during which memories are reactivated; helping to form and cement memories in the human brain.

Researchers at the University of Birmingham and Ludwig-Maximilians-University Munich today published their findings in Nature Communications.

Co-author Dr Bernhard Staresina, from the University of Birmingham's School of Psychology, commented: "Our main means of strengthening memories while we sleep is the reactivation of previously learnt information, which allows us to solidify memories in neocortical long-term stores.

"We have discovered an intricate interplay of brain activity -- slow oscillations and sleep spindles -- which create windows of opportunity enabling this reactivation."

Co-author Dr Thomas Schreiner, from Ludwig-Maximilians-University, Munich, commented: "Memory reactivation is specifically bound to the presence of SO-spindle complexes. These results shed new light on the memory function of sleep in humans and emphasise the importance of orchestrated sleep rhythms in strengthening our powers of recall and orchestrating the creation of memories."

Before this study, evidence of the brain's capacity to reactivate memories during sleep was scarce, but the team devised novel tests where participants were shown information before taking a nap and closely monitored brain activity during non-rapid eye movement (NREM) sleep using EEG recording. Those taking part were then tested on their memory recall after waking up, allowing the researchers to link the extent of memory reactivation during sleep to memory performance.

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Narcissism linked to aggression in review of 437 studies

A comprehensive analysis of 437 studies from around the world provides the best evidence to date that narcissism is an important risk factor for both aggression and violence, researchers said.

The link between narcissism and aggression was found for all dimensions of narcissism and for a variety of types of aggression. Results were similar regardless of gender, age, whether they were college students, or country of residence.

And, to have an impact, narcissism doesn't have to be at levels so high as to be pathological. Findings showed that even when narcissism was within what is considered a normal range, higher levels were linked to aggression.

"It is a pretty straightforward message: Narcissism is a significant risk factor for aggressive and violent behavior across the board," said Brad Bushman, co-author of the study and professor of communication at The Ohio State University.

The study was led by Sophie Kjaervik, a graduate student in communication at Ohio State. It was published yesterday (May 24, 2021) in the journal Psychological Bulletin.

"The link we found between narcissism and aggression was significant -- it was not trivial in size," Kjaervik said. "The findings have important real-world implications."

The researchers combined and analyzed data from many studies to provide a comprehensive view of this research area. In this meta-analysis, they examined data from 437 independent studies with a total of 123,043 participants.

Narcissism is characterized by an overblown sense of self-importance, Bushman said. The key component of narcissism is entitlement. Narcissism also has two peripheral components: grandiose (those with high self-esteem) and vulnerable (those with low self-esteem). The study found all of these components were linked to aggression.

Narcissism was related to all forms of aggression measured in the studies the researchers analyzed, including physical, verbal, bullying, direct or indirect, and displaced onto innocent targets.

"Individuals who are high in narcissism are not particularly picky when it comes to how they attack others," Kjaervik said.

Findings showed that narcissism was linked to online cyberbullying, as well as bullying offline.

"That's a highly important finding now that we live in an online world," she said.

People higher in narcissism were not only more likely to lash out in anger, but were also more likely to be "cold, deliberate and proactive" in their aggression, Bushman said.

People high in narcissism were more likely than others to be aggressive whether they were provoked or not, the study found. But the risk for aggression was significantly higher when they felt provoked, such as being ignored or insulted.

The researchers were somewhat surprised to find that the link between narcissism and violence was nearly as strong as its link with less serious forms of aggression. Violence is more rare than and is generally more difficult to predict than lesser forms of aggression, Bushman said. In this study, violence was defined as aggression intended to cause physical harm such as injury or death.

But these results are consistent with research suggesting that narcissism might be a risk factor for extremely violent acts such as mass shootings, he said.

One argument could be that the narcissism-aggression link would be more likely to occur in individualistic countries, like the United States, where people emphasize their personal rights. But the analysis found that narcissism and aggression were related even in more collectivist countries.

And findings were similar whether the research participants were college students or a more general population.

It might be tempting to think these results apply only to people who are "narcissists," but that would be wrong, Bushman said.

For one, you can't separate people into those who are narcissists and those who are not. Nearly everyone has some degree of narcissism, even though only a minority have levels high enough to be called pathological.

Findings in this study suggest that higher levels of narcissism are related to more aggression even before it reaches pathological levels.

"All of us are prone to being more aggressive when we are more narcissistic," Bushman said.

One thing that clearly stood out in the analysis, he said, was how people high in narcissism respond when they feel threatened.

"Our results suggest provocation is a key moderator of the link between narcissism and aggression," Bushman said.

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Immune cells imperfect at distinguishing between friend and foe

When it comes to distinguishing a healthy cell from an infected one that needs to be destroyed, the immune system's killer T cells sometimes make mistakes.

This discovery, described today in eLife, upends a long-held belief among scientists that T cells were nearly perfect at discriminating friend from foe. The results may point to new ways to treat autoimmune diseases that cause the immune system to attack the body, or lead to improvements in cutting-edge cancer treatments.

It is widely believed that T cells can discriminate perfectly between infected cells and healthy ones based on how tightly they are able to bind to molecules called antigens on the surface of each. They bind tightly to antigens derived from viruses or bacteria, but less tightly to our own antigens on normal cells. But recent studies by scientists looking at autoimmune diseases suggest that T cells can attack otherwise normal cells if they express unusually large numbers of our own antigens, even though these bind only weakly.

"We set out to resolve this discrepancy between the idea that T cells are near perfect at discriminating between healthy and infected cells based on the antigen binding strength, and clinical results that suggests otherwise," says co-first author Johannes Pettmann, a D.Phil student at the Sir William Dunn School of Pathology and Radcliffe Department of Medicine, University of Oxford, UK. "We did this by very precisely measuring the binding strength of different antigens."

The team measured exactly how tightly receptors on T cells bind to a large number of different antigens, and then measured how T cells from healthy humans responded to cells loaded with different amounts of these antigens. "Our methods, combined with computer modelling, showed that the T cell's receptors were better at discrimination compared to other types of receptors," says co-first author Anna Huhn, also a D.Phil student at the Sir William Dunn School of Pathology, University of Oxford. "But they weren't perfect -- their receptors compelled T cells to respond even to antigens that showed only weak binding."

"This finding completely changes how we view T cells," adds Enas Abu-Shah, Postdoctoral Fellow at the Kennedy Institute and the Sir William Dunn School of Pathology, University of Oxford, and also a co-first author of the study. "Instead of thinking of them as near-perfect discriminators of the antigen binding strength, we now know that they can respond to normal cells that simply have more of our own weakly binding antigens."

The authors say that technical issues with measuring the strength of T cell receptor binding in previous studies likely led to the mistaken conclusion that T cells are perfect discriminators, highlighting the importance of using more precise measurements.

"Our work suggests that T cells might begin to attack healthy cells if those cells produce abnormally high numbers of antigens," says senior author Omer Dushek, Associate Professor at the Sir William Dunn School of Pathology, University of Oxford, and a Senior Research Fellow in Basic Biomedical Sciences at the Wellcome Trust, UK. "This contributes to a major paradigm shift in how we think about autoimmunity, because instead of focusing on defects in how T cells discriminate between antigens, it suggests that abnormally high levels of our own antigens may be responsible for the mistaken autoimmune T-cell response. On the other hand, this ability could be helpful to kill cancer cells that mutate to express abnormally high levels of our antigens."

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36 dwarf galaxies had simultaneous 'baby boom' of new stars

Three dozen dwarf galaxies far from each other had a simultaneous "baby boom" of new stars, an unexpected discovery that challenges current theories on how galaxies grow and may enhance our understanding of the universe.

Galaxies more than 1 million light-years apart should have completely independent lives in terms of when they give birth to new stars. But galaxies separated by up to 13 million light-years slowed down and then simultaneously accelerated their birth rate of stars, according to a Rutgers-led study published in the Astrophysical Journal.

"It appears that these galaxies are responding to a large-scale change in their environment in the same way a good economy can spur a baby boom," said lead author Charlotte Olsen, a doctoral student in the Department of Physics and Astronomy in the School of Arts and Sciences at Rutgers University-New Brunswick.

"We found that regardless of whether these galaxies were next-door neighbors or not, they stopped and then started forming new stars at the same time, as if they'd all influenced each other through some extra-galactic social network," said co-author Eric Gawiser, a professor in the Department of Physics and Astronomy.

The simultaneous decrease in the stellar birth rate in the 36 dwarf galaxies began 6 billion years ago, and the increase began 3 billion years ago. Understanding how galaxies evolve requires untangling the many processes that affect them over their lifetimes (billions of years). Star formation is one of the most fundamental processes. The stellar birth rate can increase when galaxies collide or interact, and galaxies can stop making new stars if the gas (mostly hydrogen) that makes stars is lost.

Star formation histories can paint a rich record of environmental conditions as a galaxy "grew up." Dwarf galaxies are the most common but least massive type of galaxies in the universe, and they are especially sensitive to the effects of their surrounding environment.

The 36 dwarf galaxies included a diverse array of environments at distances as far as 13 million light-years from the Milky Way. The environmental change the galaxies apparently responded to must be something that distributes fuel for galaxies very far apart. That could mean encountering a huge cloud of gas, for example, or a phenomenon in the universe we don't yet know about, according to Olsen.

The scientists used two methods to compare star formation histories. One uses light from individual stars within galaxies; the other uses the light of a whole galaxy, including a broad range of colors.

"The full impact of the discovery is not yet known as it remains to be seen how much our current models of galaxy growth need to be modified to understand this surprise," Gawiser said. "If the result cannot be explained within our current understanding of cosmology, that would be a huge implication, but we have to give the theorists a chance to read our paper and respond with their own research advances."

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Explanation of how religious beliefs may be formed

Feeling anxious can direct our attention and memory toward supernatural beings such as gods, a University of Otago study has found.

Lead author Dr Thomas Swan, of the Department of Psychology, says the research may help explain how religious beliefs are formed.

For the study, published in the International Journal for the Psychology of Religion, 972 participants completed an online recall test to determine if a bias to recall supernatural agents was stronger in anxious people, rather than non-anxious people.

Those who felt anxious were more likely to remember beings with supernatural abilities than beings without.

"Anxiety is an emotion that evolved to make us pay greater attention to potential threats, so when we feel anxious, a god that can read our thoughts and punish us for them, or flood the Earth, is going to be memorable," he says.

Previous research has shown anxiety can lead to greater levels of religious belief, with the explanation being that belief provides comfort. However, this so-called 'comfort theory' has problems: why are there punishing gods and hellish afterlives when these are far from comforting?

Dr Swan believes the theory also fails to address what comes between feeling anxious and becoming a believer. This research suggests the first step involves the cognitive effects of anxiety, which cause people to attend to and recall threats.

"In our previous research, we found that supernatural beings are perceived as potentially threatening because they have abilities that defy our expectations about the world. The present research confirms that the cognitive effects of anxiety also extend to the threat that is afforded by supernatural beings.

"Ironically then, our research suggests comfort theory has it somewhat backwards: anxious people are attracted, at least initially, to the scary traits of gods, which may explain why so many gods have scary features. Comfort, we suspect, comes later when some people transform their view of the god into something more palatable that they are happier believing," he says.

The research also suggests other supernatural concepts -- such as ghosts, psychics, and astrology -- will be digested in the same way because of how they alarmingly defy our expectations about what is possible.

Dr Swan hopes the research prompts people to develop a greater understanding of how their emotional states affect the information they look at and remember, particularly religious information.

"We should all be mindful of how we came to believe the things we do, especially those with anxiety disorders who feel anxious much of the time -- they should be mindful of what they are attracted to and why. If they find themselves reading fantasy novels, that may be harmless. If they find themselves joining a cult, then it's time for some reflection. The same goes for people without disorders who are just in anxious situations, such as sitting in a hospital bed or suffering financial troubles."

On the flipside, he hopes religious groups pay more attention to people's mental states.

Read more at Science Daily

Digital Twin technology a 'powerful tool' but requires significant investment, say experts

Healthcare and aerospace experts at King's College London, The Alan Turing Institute, the University of Cambridge, and the Oden Institute for Computational Engineering and Sciences at UT Austin in Texas have said advances in digital twin technology make it a powerful tool for facilitating predictive and precision medicine and enhancing decision-making for aerospace systems. Their opinion piece was published today in Nature Computational Science.

When applied to healthcare, the digital twin, a virtual version of real-life objects that can be used to predict how that object will perform, could predict how a patient's disease will develop and how patients are likely to respond to different therapies.

It is also of huge benefit in aerospace, where, for example, the technology will be needed to monitor and control thousands of drones, ensuring that they are maintained, have efficient and safe flight plans and can automatically adapt to changes in conditions, such as weather, without the need for human interaction.

However, current digital twins are largely the result of bespoke technical solutions that are difficult to scale.

The authors say that these use cases place new demands on the speed, robustness, validation, verification and uncertainty quantification in digital twin creation workflows.

Achieving digital twins at scale will require a drastic reduction in technical barriers to their adoption.

Lead author Professor Steven Niederer from the School of Biomedical Engineering & Imaging Sciences, King's College London said in medicine, the digital twin will allow testing of a large number of therapies on a patient to identify the best option for that individual with their unique disease.

"There is, however, a need to invest in the underlying theory for how to make models, how to run these models at speed and how to combine multiple models together to ensure that they run as expected," he said.

"We also need to further develop the mathematics of how we create digital twins from patient data, how we measure uncertainty in patient data, and how to account for uncertainty in the model in predictions. These are all things which need further investment."

"We are making more measurements in patients in the hospital and from remote monitoring and we need to develop methods for rapidly and robustly combining this patient information into a digital twin to provide a single representation of the patient."

"Another challenge is how do we get better at predicting how the heart will operate under extreme conditions. We often want to predict when the heart will fail, however, we only have information that is obtained from them under normal operating procedures."

Similarly from an aerospace perspective, Dr Karen Willcox, Director, Oden Institute for Computational Engineering and Sciences at The University of Texas at Austin, said in order to be useful, the digital twin must be predictive and quantify uncertainty.

"Digital twins must be able to analyze 'what if' scenarios and issue predictions about the future, in order to guide decision making to manage a physical asset. That means the digital twin cannot be built on data alone, it needs to include both data and predictive models," she said.

Though open challenges remain, the value of digital twins is clear. And they don't have to be perfect to be valuable. "Even with existing limitations, digital twins are providing valuable decision support in many different application areas," said Willcox. "Ultimately we would like to see the technology used in every engineering system. At that point we can start thinking not just about how a digital twin might change the way we operate the system, but also how we design it in the first place."

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Diabetes vaccine gives promising results in a genetic subgroup

A clinical study led by Linköping University and financed by pharmaceuticals company Diamyd Medical has investigated whether immunotherapy against type 1 diabetes can preserve the body's own production of insulin. The results suggest that injection of a protein, GAD, into lymph nodes can be effective in a subgroup of individuals. The results have been published in Diabetes Care.

In type 1 diabetes, the body's immune system attacks the cells that produce insulin. When the insulin-producing cells have disappeared, the body can no longer regulate blood sugar level, and a person with type 1 diabetes must take exogenous insulin for the rest of his or her life.

A highly topical question in research into type 1 diabetes is whether, and if so how, the attack of the immune system can be slowed or even completely stopped. One possible strategy is based on altering the immune defence by injecting a protein that the cells of the immune system react to, in a form of vaccination. One of the proteins against which the immune system often forms antibodies in type 1 diabetes is known as GAD65 (glutamic acid decarboxylase). Professor Johnny Ludvigsson at Linköping University has studied for many years the possibility of vaccinating people who have newly diagnosed type 1 diabetes with GAD. It is hoped that the immune system will become more tolerant against the body's own GAD, and stop damaging the insulin-producing cells, such that the body can continue to form some insulin.

"Studies have shown that even an extremely small production of insulin in the body is highly beneficial for patient health. People with diabetes who produce a certain amount of insulin naturally do not develop low blood sugar levels, hypoglycaemia, so easily. They have also a lower risk of developing the life-threatening condition ketoacidosis, which can arise when the insulin level is low," says Johnny Ludvigsson, senior professor in the Department of Biomedical and Clinical Sciences at Linköping University.

Johnny Ludvigsson has led DIAGNODE-2, a clinical phase 2 study in which researchers investigated the effect of GAD-alum (Diamyd) injections into the lymph nodes of 109 young people with recently diagnosed type 1 diabetes. The natural insulin production of the participants was measured at the start of the study and again after 15 months. Several other outcome measures were also followed, such as change in long-term blood sugar levels (HbA1c), and how much supplementary insulin the patients needed to take every day.

Previous studies of immunotherapy in diabetes have suggested that genetic factors play a role in how patients respond to the treatment. This led the researchers in DIAGNODE-2 to look at several variants of what are known as "HLA genes." These genes code for proteins located on the surface of some cells. They function as holders of proteins, and expose them to immune system cells passing by. If the protein fragment exposed in this way comes from, for example, bacteria, the immune system should form antibodies against the foreign protein. However, the immune system sometimes reacts against the body's own substances, and certain types of HLA are associated with an increased risk of type 1 diabetes. The HLA variant HLA-DR3-DQ2 exposes the GAD65 protein to cells of the immune system, and patients with this variant often form antibodies against GAD65 at an early stage of the disease. Around half of the participants in the study had the HLA-DR3-DQ2 variant.

For the complete patient group, there was no difference between treatment and placebo in the degree to which insulin production was preserved. GAD-alum did, however, have a positive effect for the subgroup of patients who had the DR3-DQ2 variant of HLA genes.

"The patients in the subgroup with the DR3-DQ2 type of HLA genes did not lose insulin production as quickly as the other patients. In contrast, we did not see any significant effect in the patients who did not have this HLA type," says Johnny Ludvigsson.

No undesired effects that could be related to treatment with GAD-alum were seen during the study.

"Treatment with GAD-alum seems to be a promising, simple and safe way to preserve insulin production in around half of patients with type 1 diabetes, the ones who have the right type of HLA. This is why we are looking forward to carrying out larger studies, and we hope these will lead to a drug that can change the progress of type 1 diabetes," says Johnny Ludvigsson.

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Origins of life researchers develop a new ecological biosignature

When scientists hunt for life, they often look for biosignatures, chemicals or phenomena that indicate the existence of present or past life. Yet it isn't necessarily the case that the signs of life on Earth are signs of life in other planetary environments. How do we find life in systems that do not resemble ours?

In groundbreaking new work, a team* led by Santa Fe Institute Professor Chris Kempes has developed a new ecological biosignature that could help scientists detect life in vastly different environments. Their work appears as part of a special issue of the Bulletin of Mathematical Biology collected in honor of renowned mathematical biologist James D. Murray.

The new research takes its starting point from the idea that stoichiometry, or chemical ratios, can serve as biosignatures. Since "living systems display strikingly consistent ratios in their chemical make-up," Kempes explains, "we can use stoichiometry to help us detect life." Yet, as SFI Science Board member and contributor, Simon Levin, explains, "the particular elemental ratios we see on Earth are the result of the particular conditions here, and a particular set of macromolecules like proteins and ribosomes, which have their own stoichiometry." How can these elemental ratios be generalized beyond the life that we observe on our own planet?

The group solved this problem by building on two lawlike patterns, two scaling laws, that are entangled in elemental ratios we have observed on Earth. The first of these is that in individual cells, stoichiometry varies with cell size. In bacteria, for example, as cell size increases, protein concentrations decrease, and RNA concentrations increase. The second is that the abundance of cells in a given environment follows a power-law distribution. The third, which follows from integrating the first and second into a simple ecological model, is that the elemental abundance of particles to the elemental abundance in the environmental fluid is a function of particle size.

While the first of these (that elemental ratios shift with particle size) makes for a chemical biosignature, it is the third finding that makes for the new ecological biosignature. If we think of biosignatures not simply in terms of single chemicals or particles, and instead take account of the fluids in which particles appear, we see that the chemical abundances of living systems manifest themselves in mathematical ratios between the particle and environment. These general mathematical patterns may show up in coupled systems that differ significantly from Earth.

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Superficial relationship: Enzymes protect the skin by ignoring microbes and viruses

The human body is constantly exposed to various environmental actors, from viruses to bacteria to fungi, but most of these microbial organisms provoke little or no response from our skin, which is charged with monitoring and protecting from external dangers.

Until now, researchers weren't quite sure how that happened -- and why our skin wasn't constantly alarmed and inflamed.

In a study published May 21, 2021 in Science Immunology, scientists at University of California San Diego School of Medicine identify and describe two enzymes responsible for protecting our skin and body's overall health from countless potential microbial intruders. These enzymes, called histone deacetylases (HDACs), inhibit the body's inflammatory response in the skin.

"We have figured out why we tolerate certain microbes living on our skin, while the same bacteria would make us very sick if exposed elsewhere in the body," said Richard Gallo, MD, PhD, Ima Gigli Distinguished Professor of Dermatology and chair of the Department of Dermatology at UC San Diego School of Medicine. "In our research, we identified enzymes that act on the chromosome of specific skin cells that provide immune tolerance by the skin.

"Without these enzymes telling our cells to ignore certain bacteria, we'd have a constant rash on our skin."

Gallo and colleagues say the potential mechanism for how the environment can interact and alter cell function is through epigenetic control of gene expression. Within the skin cells, proteins called toll-like receptors (TLRs) allow the cells to sense their surroundings and potential dangers.

In most organs, TLRs act as a warning system that triggers an inflammatory response to threats. But in skin cells, the two identified HDAC enzymes, HDAC8 and HDAC9, inhibit the inflammatory response.

"This is one of the first demonstrations of how the microbiome can interact with epigenetic factors in the skin and modulate the skin's behavior through the inflammatory response," said George Sen, PhD, associate professor of dermatology and cellular and molecular medicine at UC San Diego School of Medicine. "Whatever environment we're facing can change a person's specific response to it. Since this epigenetic change is reversible, unlike alterations to our DNA, we can potentially control our skin inflammatory response through targeting of these enzymes."

The research was initially conducted in mouse models in which HDAC8 and HDAC9 had been genetically knocked out. As a result, the mice's skin could not tolerate microbial or viral exposures, resulting in a heightened immune reaction. The team then reproduced the findings with human cells in a culture dish.

Gallo said the work could change how doctors treat certain types of skin inflammation or other dermatologic conditions.

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