Searching for life with space dust

Following enormous collisions, such as asteroid impacts, some amount of material from an impacted world may be ejected into space. This material can travel vast distances and for extremely long periods of time. In theory this material could contain direct or indirect signs of life from the host world, such as fossils of microorganisms. And this material could be detectable by humans in the near future, or even now.

When you hear the words vacuum and dust in a sentence, you may groan at the thought of having to do the housework. But in astronomy, these words have different connotations. Vacuum of course refers to the void of space. Dust, however, means diffuse solid material floating through space. It can be an annoyance to some astronomers as it may hinder their views of some distant object. Or dust could be a useful tool to help other astronomers learn about something distant without having to leave the safety of our own planet. Professor Tomonori Totani from the University of Tokyo's Department of Astronomy has an idea for space dust that might sound like science fiction but actually warrants serious consideration.

"I propose we study well-preserved grains ejected from other worlds for potential signs of life," said Totani. "The search for life outside our solar system typically means a search for signs of communication, which would indicate intelligent life but precludes any pre-technological life. Or the search is for atmospheric signatures that might hint at life, but without direct confirmation there could always be an explanation that does not require life. However, if there are signs of life in dust grains, not only could we be certain, but we could also find out soon."

The basic idea is that large asteroid strikes can eject ground material into space. There is a chance that recently deceased or even fossilized microorganisms could be contained in some rocky material in this ejecta. This material will vary in size greatly, with different-sized pieces behaving differently once in space. Some larger pieces might fall back down or enter permanent orbits around a local planet or star. And some much smaller pieces might be too small to contain any verifiable signs of life. But grains in the region of 1 micrometer (one-thousandth of a millimeter) could not only host a specimen of a single-celled organism, but they could also potentially escape their host solar system altogether, and under the right circumstances, maybe even venture to ours.

"My paper explores this idea using available data on the different aspects of this scenario," said Totani. "The distances and times involved can be vast, and both reduce the chance any ejecta containing life signs from another world could even reach us. Add to that the number of phenomena in space that can destroy small objects due to heat or radiation, and the chances get even lower. Despite that, I calculate around 100,000 such grains could be landing on Earth every year. Given there are many unknowns involved, this estimate could be too high or too low, but the means to explore it already exist so it seems like a worthwhile pursuit."

There may be such grains already on Earth, and in plentiful amounts, preserved in places such as the Antarctic ice, or under the seafloor. Space dust in these places could be retrieved relatively easily, but discerning extrasolar material from material originating in our own solar system is still a complex matter. If the search is extended to space itself, however, there are already missions that capture dust in the vacuum using ultralight materials called aerogels.

Read more at Science Daily

Turn up your favorite song to improve medication efficacy

While listening to a favorite song is a known mood booster, researchers at Michigan State University have discovered that music-listening interventions also can make medicines more effective.

"Music-listening interventions are like over-the-counter medications," said Jason Kiernan, an assistant professor in the College of Nursing. "You don't need a doctor to prescribe them."

While previous research studies have used music-listening interventions as a tool to treat pain and anxiety, Kiernan took a novel approach by studying the effects of music-listening interventions on chemotherapy-induced nausea.

"Pain and anxiety are both neurological phenomena and are interpreted in the brain as a state," Kiernan said. "Chemotherapy-induced nausea is not a stomach condition; it is a neurological one."

The small pilot study included 12 patients undergoing chemotherapy treatment who agreed to listen to their favorite music for 30 minutes each time they needed to take their as-needed anti-nausea medication. They repeated the music intervention anytime nausea occurred over the five days beyond their chemotherapy treatment. The patients in the study provided a total of 64 events.

"When we listen to music, our brains fire all kinds of neurons," Kiernan said.

While Kiernan did see a reduction in the ratings of patients' nausea severity and their distress (how much it bothered them to be nauseous), he cautions that it is difficult to isolate whether it was the gradual release of the medication doing its job or the increased benefit of the music. For future studies, Kiernan is drawing inspiration from another previously published study that measured the amount of serotonin, a neurotransmitter, that was released by platelets in the blood after listening to unpleasant and pleasant music.

"Serotonin is the major neurotransmitter that causes chemotherapy-induced nausea," Kiernan said. "Cancer patients take medications to block serotonin's effects."

During that previous study, researchers found that patients who listened to pleasant music experienced the lowest levels of serotonin release, indicating that the serotonin stayed in the blood platelets and was not released to circulate throughout the body. Results also showed that after listening to music they found unpleasant, patients experienced greater stress and increased levels of serotonin release.

"This was intriguing because it provides a neurochemical explanation and a possible way to measure serotonin and the blood platelet release of serotonin in my study," Kiernan said. "In 10 to 20 years, wouldn't it be neat if you could use a nonpharmacological intervention like listening to 10 minutes of your favorite music to complement a medicine?"

Read more at Science Daily

AI finds the first stars were not alone

By using machine learning and state-of-the-art supernova nucleosynthesis, a team of researchers have found the majority of observed second-generation stars in the universe were enriched by multiple supernovae, reports a new study in The Astrophysical Journal.

Nuclear astrophysics research has shown elements including and heavier than carbon in the universe are produced in stars. But the first stars, stars born soon after the Big Bang, did not contain such heavy elements, which astronomers call 'metals'. The next generation of stars contained only a small amount of heavy elements produced by the first stars. To understand the universe in its infancy, it requires researchers to study these metal-poor stars.

Luckily, these second-generation metal-poor stars are observed in our Milky Way Galaxy, and have been studied by a team of Affiliate Members of the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) to close in on the physical properties of the first stars in the universe.

The team, led by Kavli IPMU Visiting Associate Scientist and The University of Tokyo Institute for Physics of Intelligence Assistant Professor Tilman Hartwig, including Visiting Associate Scientist and National Astronomical Observatory of Japan Assistant Professor Miho Ishigaki, Visiting Senior Scientist and University of Hertfordshire Professor Chiaki Kobayashi, Visiting Senior Scientist and National Astronomical Observatory of Japan Professor Nozomu Tominaga, and Visiting Senior Scientist and The University of Tokyo Professor Emeritus Ken'ichi Nomoto, used artificial intelligence to analyze elemental abundances in more than 450 extremely metal-poor stars observed to date. Based on the newly developed supervised machine learning algorithm trained on theoretical supernova nucleosynthesis models, they found that 68 per cent of the observed extremely metal-poor stars have a chemical fingerprint consistent with enrichment by multiple previous supernovae.

The team's results give the first quantitative constraint based on observations on the multiplicity of the first stars.

"Multiplicity of the first stars were only predicted from numerical simulations so far, and there was no way to observationally examine the theoretical prediction until now," said lead author Hartwig. "Our result suggests that most first stars formed in small clusters so that multiple of their supernovae can contribute to the metal enrichment of the early interstellar medium," he said.

"Our new algorithm provides an excellent tool to interpret the big data we will have in the next decade from on-going and future astronomical surveys across the world" said Kobayashi, also a Leverhulme Research Fellow.

"At the moment, the available data of old stars are the tip of the iceberg within the solar neighborhood. The Prime Focus Spectrograph, a cutting-edge multi-object spectrograph on the Subaru Telescope developed by the international collaboration led by Kavli IPMU, is the best instrument to discover ancient stars in the outer regions of the Milky Way far beyond the solar neighborhood.," said Ishigaki.

The new algorithm invented in this study opens the door to make the most of diverse chemical fingerprints in metal-poor stars discovered by the Prime Focus Spectrograph.

Read more at Science Daily

Ancient genomes reveal immunity adaptation in early farmers

Research from the Francis Crick Institute published today in Current Biology has revealed that diversity in genes coding for immunity may have facilitated adaptation to farming lifestyles in prehistoric periods.

Researchers at the Ancient Genomics Laboratory at the Crick studied available genome-wide DNA from 677 individuals dating to Stone Age Europe, spanning the movement of Neolithic farmers from the Near East into Europe about 8000 years ago, where they mixed with Mesolithic hunter-gatherers already in Europe.

They were interested in whether any particular genes might have coded for adaptations important to early farming groups, and looked for evidence of rapid evolution in these populations.

Since about 20% of the ancestry of descendant late Stone Age people could be traced to the local European hunter-gatherers, the researchers also asked whether any particular genes showed evidence of more hunter-gatherer ancestry.

They found that a large genetic region responsible for immune responses to diseases -- the major histocompatibility complex (MHC) -- showed both the strongest evidence of rapid evolution, and more Mesolithic hunter-gatherer ancestry than expected, suggesting that genetic variants in the MHC region already present in Europe were passed down preferentially.

It has previously been thought that the transition to farming was associated with increased natural selection on immunity variants, as people started living closer to animals and eating more animal products. This research supports this view, but also shows that diversity in immune genes may be just as important as adaptation to lifestyle.

The research team speculates that either the hunter-gatherers already had genetic adaptations against bacteria, viruses or other microorganisms in Europe, or that having many different forms of the genes was advantageous.

Tom Davy, PhD student at the Francis Crick Institute and lead author, said: "It was really exciting to see for the first time that immunity is important for the transition to farming in a prehistoric population. The later Neolithic people had far more farmer ancestry in general, so we expected to see the same at the MHC region, especially as many diseases have been linked to Neolithic periods. But we saw about 50:50 ancestry from Neolithic farmers and Mesolithic hunter-gatherers here, showing that natural selection favoured genes from the hunter-gatherers already in Europe.

"At the moment we're not quite sure whythis happened, but a proposal is that the European hunter-gatherers had genetic variations which allowed them to fight Europe-specific diseases. Or picking up a variety of genes from both hunter-gatherers and farmers was beneficial because it resulted in lots of diversity at this major group of genes, allowing people to better fight off disease."

The team also confirmed results from previous studies, showing that genes coding for skin pigmentation showed the greatest representation for Neolithic farmer ancestry, with these variations coming into Europe from the Near East. This may be to maintain vitamin D levels when sources, such as diet and exposure to sunlight, change.

Pontus Skoglund, Group Leader of the Ancient Genomics Laboratory at the Crick, said: "The shift to farming was an important transition all over the world, resulting in changing diets and exposure to infectious disease.

Read more at Science Daily

How the brain's 'internal compass' works

Scientists have gained new insights into the part of the brain that gives us a sense of direction, by tracking neural activity with the latest advances in brain imaging techniques. The findings shed light on how the brain orients itself in changing environments -- and even the processes that can go wrong with degenerative diseases like dementia, that leave people feeling lost and confused.

"Neuroscience research has witnessed a technology revolution in the last decade allowing us to ask and answer questions that could only be dreamed of just years ago," says Mark Brandon, an Associate Professor of psychiatry at McGill University and researcher at the Douglas Research Centre, who co-led the research with Zaki Ajabi, a former student at McGill University and now a postdoctoral research fellow at Harvard University.

Reading the brain's internal compass

To understand how visual information impacts the brain's internal compass, the researchers exposed mice to a disorienting virtual world while recording the brain's neural activity. The team recorded the brain's internal compass with unprecedented precision using the latest advances in neuronal recording technology.

This ability to accurately decode the animal's internal head direction allowed the researchers to explore how the Head-Direction cells, which make up the brain's internal compass, support the brain's ability to re-orient itself in changing surroundings. Specifically, the research team identified a phenomenon they term 'network gain' that allowed the brain's internal compass to reorient after the mice were disoriented. "It's as if the brain has a mechanism to implement a 'reset button' allowing for rapid reorientation of its internal compass in confusing situations," says Ajabi.

Although the animals in this study were exposed to unnatural visual experiences, the authors argue that such scenarios are already relevant to the modern human experience, especially with the rapid spread of virtual reality technology. These findings "may eventually explain how virtual reality systems can easily take control over our sense of orientation," adds Ajabi.

The results inspired the research team to develop new models to better understand the underlying mechanisms. "This work is a beautiful example of how experimental and computational approaches together can advance our understanding of brain activity that drives behaviour," says co-author Xue-Xin Wei, a computational neuroscientist and an Assistant Professor at The University of Texas at Austin.

Read more at Science Daily

Novel drug makes mice skinny even on sugary, fatty diet

Researchers from The University of Texas Health Science Center at San Antonio (UT Health San Antonio) have developed a small-molecule drug that prevents weight gain and adverse liver changes in mice fed a high-sugar, high-fat Western diet throughout life.

"When we give this drug to the mice for a short time, they start losing weight. They all become slim," said Madesh Muniswamy, PhD, professor of medicine in the health science center's Joe R. and Teresa Lozano Long School of Medicine.

Findings by the collaborators, also from the University of Pennsylvania and Cornell University, were published Feb. 27 in the high-impact journal Cell Reports. Muniswamy, director of the Center for Mitochondrial Medicine at UT Health San Antonio, is the senior author.

Fourth most common element

The research team discovered the drug by first exploring how magnesium impacts metabolism, which is the production and consumption of energy in cells. This energy, called ATP, fuels the body's processes.

Magnesium is the fourth most abundant element in the body after calcium, potassium and sodium, and plays many key roles in good health, including regulating blood sugar and blood pressure and building bones. But the researchers found that too much magnesium slows energy production in mitochondria, which are cells' power plants.

"It puts the brake on, it just slows down," said co-lead author Travis R. Madaris, doctoral student in the Muniswamy laboratory at UT Health San Antonio.

Deleting MRS2, a gene that promotes magnesium transport into the mitochondria, resulted in more efficient metabolism of sugar and fat in the power plants. The result: skinny, healthy mice.

Liver and adipose (fat) tissues in the rodents showed no evidence of fatty liver disease, a complication related to poor diet, obesity and type 2 diabetes.

Small-molecule agent

The drug, which the researchers call CPACC, accomplishes the same thing. It restricts the amount of magnesium transfer into the power plants. In experiments, the result was again: skinny, healthy mice. UT Health San Antonio has filed a patent application on the drug.

The mice served as a model system of long-term dietary stress precipitated by the calorie-rich, sugary and fatty Western diet. The familiar results of this stress are obesity, type 2 diabetes and cardiovascular complications.

"Lowering the mitochondrial magnesium mitigated the adverse effects of prolonged dietary stress," said co-lead author Manigandan Venkatesan, PhD, postdoctoral fellow in the Muniswamy lab.

Joseph A. Baur, PhD, of the University of Pennsylvania and Justin J. Wilson, PhD, of Cornell are among the collaborators. "We came up with the small molecule and Justin synthesized it," Madaris said.

Read more at Science Daily

Surprisingly simple explanation for the alien comet 'Oumuamua's weird orbit

In 2017, a mysterious comet dubbed 'Oumuamua fired the imaginations of scientists and the public alike. It was the first known visitor from outside our solar system, it had no bright coma or dust tail, like most comets, and a peculiar shape -- something between a cigar and a pancake -- and its small size more befitted an asteroid than a comet.

But the fact that it was accelerating away from the sun in a way that astronomers could not explain perplexed scientists, leading some to suggest that it was an alien spaceship.

Now, a University of California, Berkeley, astrochemist and a Cornell University astronomer argue that the comet's mysterious deviations from a hyperbolic path around the sun can be explained by a simple physical mechanism likely common among many icy comets: outgassing of hydrogen as the comet warmed up in the sunlight.

What made 'Oumuamua different from every other well-studied comet in our solar system was its size: It was so small that its gravitational deflection around the sun was slightly altered by the tiny push created when hydrogen gas spurted out of the ice.

Most comets are essentially dirty snowballs that periodically approach the sun from the outer reaches of our solar system. When warmed by sunlight, a comet ejects water and other molecules, producing a bright halo or coma around it and often tails of gas and dust. The ejected gases act like the thrusters on a spacecraft to give the comet a tiny kick that alters its trajectory slightly from the elliptical orbits typical of other solar system objects, such as asteroids and planets.

When discovered, 'Oumuamua had no coma or tail and was too small and too far from the sun to capture enough energy to eject much water, which led astronomers to speculate wildly about its composition and what was pushing it outward. Was it a hydrogen iceberg outgassing H2? A large, fluffy snowflake pushed by light pressure from the sun? A light sail created by an alien civilization? A spaceship under its own power?

Jennifer Bergner, a UC Berkeley assistant professor of chemistry who studies the chemical reactions that occur on icy rocks in the cold vacuum of space, thought there might be a simpler explanation. She broached the subject with a colleague, Darryl Seligman, now an National Science Foundation postdoctoral fellow at Cornell University, and they decided to work together to test it.

"A comet traveling through the interstellar medium basically is getting cooked by cosmic radiation, forming hydrogen as a result. Our thought was: If this was happening, could you actually trap it in the body, so that when it entered the solar system and it was warmed up, it would outgas that hydrogen?" Bergner said. "Could that quantitatively produce the force that you need to explain the non-gravitational acceleration?"

Surprisingly, she found that experimental research published in the 1970s, '80s and '90s demonstrated that when ice is hit by high-energy particles akin to cosmic rays, molecular hydrogen (H2) is abundantly produced and trapped within the ice. In fact, cosmic rays can penetrate tens of meters into ice, converting a quarter or more of the water to hydrogen gas.

"For a comet several kilometers across, the outgassing would be from a really thin shell relative to the bulk of the object, so both compositionally and in terms of any acceleration, you wouldn't necessarily expect that to be a detectable effect," she said. "But because 'Oumuamua was so small, we think that it actually produced sufficient force to power this acceleration."

The comet, which was slightly reddish, is thought to have been roughly 115 by 111 by 19 meters in size. While the relative dimensions were fairly certain, however, astronomers couldn't be sure of the actual size because it was too small and distant for telescopes to resolve. The size had to be estimated from the comet's brightness and how the brightness changed as the comet tumbled. To date, all the comets observed in our solar system -- the short-period comets originating in the Kuiper belt and the long-period comets from the more distant Oort cloud have ranged from around 1 kilometer to hundreds of kilometers across.

"What's beautiful about Jenny's idea is that it's exactly what should happen to interstellar comets," Seligman said. "We had all these stupid ideas, like hydrogen icebergs and other crazy things, and it's just the most generic explanation."

Bergner and Seligman will publish their conclusions this week in the journal Nature. Both were postdoctoral fellows at the University of Chicago when they began collaborating on the paper.

Messenger from afar

Comets are icy rocks left over from the formation of the solar system 4.5 billion years ago, so they can tell astronomers about the conditions that existed when our solar system formed. Interstellar comets can also give hints to the conditions around other stars surrounded by planet-forming disks.

"Comets preserve a snapshot of what the solar system looked like when it was in the stage of evolution that protoplanetary disks are now," Bergner said. "Studying them is a way to look back at what our solar system used to look like in the early formation stage."

Faraway planetary systems also seem to have comets, and many are likely to be ejected because of gravitational interactions with other objects in the system, which astronomers know happened over the history of our solar system. Some of these rogue comets should occasionally enter our solar system, providing an opportunity to learn about planet formation in other systems.

"The comets and asteroids in the solar system have arguably taught us more about planet formation than what we've learned from the actual planets in the solar system," Seligman said. "I think that the interstellar comets could arguably tell us more about extrasolar planets than the extrasolar planets we are trying to get measurements of today."

In the past, astronomers published numerous papers about what we can learn from the failure to observe any interstellar comets in our solar system.

Then, 'Oumuamua came along.

On Oct. 19, 2017, on the island of Maui, astronomers using the Pan-STARRS1 telescope, which is operated by the Institute for Astronomy at the University of Hawaii in Manoa, first noticed what they thought was either a comet or an asteroid. Once they realized that its tilted orbit and high speed -- 87 kilometers per second -- implied that it came from outside our solar system, they gave it the name 1I/'Oumuamua (oh MOO-uh MOO-uh), which is Hawai'ian for "a messenger from afar arriving first." It was the first interstellar object aside from dust grains ever seen in our solar system. A second, 2I/Borisov, was discovered in 2019, though it looked and behaved more like a typical comet.

As more and more telescopes focused on 'Oumuamua, the astronomers were able to chart its orbit and determine that it had already looped around the sun and was headed out of the solar system.

Because 'Oumuamua's brightness changed periodically by a factor of 12 and varied asymmetrically, it was assumed to be highly elongated and tumbling end over end. Astronomers also noticed a slight acceleration away from the sun larger than seen for asteroids and more characteristic of comets. When comets approach the sun, the water and gases ejected from the surface create a glowing, gaseous coma and release dust in the process. Typically, dust left in the comet's wake becomes visible as one tail, while vapor and dust pushed by light pressure from solar rays produces a second tail pointing away from the sun, plus a little inertial push outward. Other compounds, such as entrapped organic materials and carbon monoxide, also can be released.

Why was it accelerating?

But astronomers could detect no coma, outgassed molecules or dust around 'Oumuamua. In addition, calculations showed that the solar energy hitting the comet would be insufficient to sublimate water or organic compounds from its surface to give it the observed non-gravitational kick. Only hypervolatile gases such as H2, N2 or carbon monoxide (CO) could provide enough acceleration to match observations, given the incoming solar energy.

"We had never seen a comet in the solar system that didn't have a dust coma. So, the non-gravitational acceleration really was weird," Seligman said.

This led to much speculation about what volatile molecules could be in the comet to cause the acceleration. Seligman himself published a paper arguing that if the comet was composed of solid hydrogen -- a hydrogen iceberg -- it would outgas enough hydrogen in the heat of the sun to explain the strange acceleration. Under the right conditions, a comet composed of solid nitrogen or solid carbon monoxide would also outgas with enough force to affect the comet's orbit.

But astronomers had to stretch to explain what conditions could lead to the formation of solid bodies of hydrogen or nitrogen, which have never been observed before. And how could a solid H2 body survive for perhaps 100 million years in interstellar space?

Bergner thought that outgassing of hydrogen entrapped in ice might be sufficient to accelerate 'Oumuamua. As both an experimentalist and a theoretician, she studies the interaction of very cold ice -- chilled to 5 or 10 degrees Kelvin, the temperature of the interstellar medium (ISM) -- with the kinds of energetic particles and radiation found in the ISM.

In searching through past publications, she found many experiments demonstrating that high-energy electrons, protons and heavier atoms could convert water ice into molecular hydrogen, and that the fluffy, snowball structure of a comet could entrap the gas in bubbles within the ice. Experiments showed that when warmed, as by the heat of the sun, the ice anneals -- changes from an amorphous to a crystal structure -- and forces the bubbles out, releasing the hydrogen gas. Ice at the surface of a comet, Bergner and Seligman calculated, could emit enough gas, either in a collimated beam or fan-shaped spray, to affect the orbit of a small comet like 'Oumuamua.

"The main takeaway is that 'Oumuamua is consistent with being a standard interstellar comet that just experienced heavy processing," Bergner said. "The models we ran are consistent with what we see in the solar system from comets and asteroids. So, you could essentially start with something that looks like a comet and have this scenario work."

The idea also explains the lack of a dust coma.

"Even if there was dust in the ice matrix, you're not sublimating the ice, you're just rearranging the ice and then letting H2 get released. So, the dust isn't even going to come out," Seligman said.

'Dark' comets

Seligman said that their conclusion about the source of 'Oumuamua's acceleration should close the book on the comet. Since 2017, he, Bergner and their colleagues have identified six other small comets with no observable coma, but with small non-gravitational accelerations, suggesting that such "dark" comets are common. While H2 is not likely responsible for the accelerations of dark comets, Bergner noted, together with 'Oumuamua they reveal that there is much to be learned about the nature of small bodies in the solar system.

One of these dark comets, 1998 KY26, is the next target for Japan's Hayabusa2 mission, which recently collected samples from the asteroid Ryugu. The 1998 KY26 was thought to be an asteroid until it was identified as a dark comet in December.

"Jenny's definitely right about the entrapped hydrogen. Nobody had thought of that before," he said. "Between discovering other dark comets in the solar system and Jenny's awesome idea, I think it's got to be correct. Water is the most abundant component of comets in the solar system and likely in extrasolar systems, as well. And if you put a water rich comet in the Oort cloud or eject it into the interstellar medium, you should get amorphous ice with pockets of H2."

Because H2 should form in any ice-rich body exposed to energetic radiation, the researchers suspect that the same mechanism would be at work in sun-approaching comets from the Oort cloud at the outer reaches of the solar system, where comets are irradiated by cosmic rays, much like an interstellar comet would be. Future observations of hydrogen outgassing from long-period comets could be used to test the scenario of H2 formation and entrapment.

Read more at Science Daily

Sea ice will soon disappear from the Arctic during the summer months -- and it has happened before

The "Last Ice Area" north of Greenland and Canada is the last sanctuary of all-year sea ice in this time of rising temperatures caused by climate change. A new study now suggests that this may soon be over.

Researchers from Aarhus University, in collaboration with Stockholm University and the United States Geological Survey, analyzed samples from the previously inaccessible region north of Greenland.

The sediment samples were collected from the seabed in the Lincoln Sea, part of the "Last Ice Area." They showed that the sea ice in this region melted away during summer months around 10,000 years ago. The research team concluded that summer sea ice melted at a time when temperatures were at a level that we are rapidly approaching again today.

"Climate models have suggested that summer sea ice in this region will melt in the coming decades, but it's uncertain if it will happen in 20, 30, 40 years, or more. This project has demonstrated that we're very close to this scenario, and that temperatures only have to increase a little before the ice will melt," says Christof Pearce, Assistant Professor at the Department of Geoscience, Aarhus University.

The researchers have used data from the Early Holocene period to predict when the sea ice will melt today. During this time period, summer temperatures in the Arctic were higher than today. Although this was caused by natural climate variability opposed to the human-induced warming, it still is a natural laboratory for studying the fate of this region in the immediate future.

In Aarhus the marine samples have been analysed in collaboration with Associate Professor Marianne Glasius and academic technical staff Mads Mørk Jensen from the Department of Chemistry. Among other things, they studied molecules from certain algae that are only produced when there is sea ice. The researchers can thereby determine when summer sea ice was present in the area.

A wake-up call

When the sea ice in the Lincoln Sea begins to melt during the summer months, it can have major consequences for the climate. Where white ice reflects the rays of the sun, a dark sea will absorb more than ten times as much solar energy and thereby increase global warming. Moreover, it can affect ecosystems:

"The sea ice is a base for many ecosystems. The algae we examined are food for fish, fish are food for birds, etc. How will the marine ecosystems be affected globally if the sea ice disappears? We don't know the answer yet," says Henrieka Detlef, an assistant professor at the Department of Geoscience.

According to the researchers from Aarhus University, the study can be interpreted as good and bad news for the climate.

"The bad news is that we can see this happening very soon. The good news is that our data shows the trend is reversible and we can do something about it if we reduce greenhouse gas emissions and set ambitious political goals. If we can keep temperatures stable or perhaps even make them fall, the sea ice would return to the area," says Henrieka Detlef.

Read more at Science Daily

Geoscientists shed a light on life's evolution 800 million years ago

Is nitrate responsible for algae, flowers, and even your neighbors?

A team of Virginia Tech geoscientists have unearthed evidence that may indicate yes.

The team's findings, recently published in Science Advances, reveal an increase in biologically available nitrogen during the time that marine eukaryotes -- organisms whose cells have a nucleus -- became dominate. Complex eukaryotic cells evolved into multicellular organisms and are credited for ushering in a whole new era for life on Earth, including animals, plants, and fungi.

"Where we sit today, with life as it is on the planet, is the sum total of all the events that happened in the past," said Ben Gill, an associate professor of sedimentary geochemistry and co-author on the paper. "And this is a key event where we shift from dominantly prokaryotic ecosystems -- cells that are much simpler than the ones in our bodies -- to eukaryotes. If that did not happen, we would not be here today."

Previous research focused on phosphorus' role in the rise of eukaryotes, but Junyao Kang, a doctoral student in the Department of Geosciences and lead author of the paper, was curious about the part nitrogen played in this event.

"This data is unique because nitrogen isotope data are virtually nonexistent from the early Neoproterozoic time period, or between a billion and 800 million years ago," said Kang.

Collaborating with the Nanjing University in Najing, China, Kang has spent two years working to understand what drove the rise of eukaryotes through nitrogen isotope analysis of rock samples from the North China Craton. Home to rocks dating back 3.8 billion years ago, the region was once covered by an ocean.

"We had some rough ideas of when eukaryotes became ecologically successful," said Shuhai Xiao, professor of geobiology and a paper co-author. "They had been there for a long time in a low-key status until about 820 million years ago, when they became abundant."

Kang decided he wanted to learn why. He took the data from the rock samples, entered it into a larger database, and analyzed it across a longer time scale that spanned different geographic locations.

"Once we did this kind of integration and put it into a big picture, we saw the rise of nitrates through time, which happened around 800 million years ago," said Kang.

Solid collaboration

A collaborative, international approach was key to connecting this new data with biological events, mostly notably, the rise of eukaryotes.

Gill and Rachel Reid, also a College of Science geochemist and co-author of the paper, provided critical analyses through resources, including the mass spectrometer in the Geoscience Stable Isotope Lab at Virginia Tech. An elemental analyzer coupled to the mass spectrometer allowed the researchers to extract pure nitrogen gas from the samples for analysis.

Gill specializes in reconstructing present and past chemical cycles on our planet. He collaborates with paleontologists to study the record of life preserved in the geological record and examines what potential environmental drivers might have enabled changes in life through history.

Reid, who generally focuses her research on Earth's more recent events, had a special opportunity to offer her nitrogen isotope expertise to these ancient fossils.

Feifei Zhang, a geochemist at Nanjing University, was the paper's fourth co-author. Zhang provided insights on how much oxygen would have been available in the oceans during the time when nitrate increased in abundance.

All of the Virginia Tech authors are affiliated members of the Fralin Life Sciences Institute's Global Change Center, with Kang serving as a Ph.D. fellow in the Interfaces of Global Change graduate program. The center brings together experts from diverse disciplines to solve these complex global challenges and train the next generation of leaders.

Past, present, and future

Xiao, who has helped excavate and study some of the most ancient fossils from around the world, said this type of study gives him hope for future discoveries. The team members look forward to collaborating with NASA on future grants, such as the exobiology program supporting their current research.

He also credits University Libraries at Virginia Tech for its support of open-access publications, such as Science Advances, to provide a vetted selection of research, freely available to readers.

"We can link the dots from the nitrogen isotopic compositions in the ancient past and then go to the next step and infer how much nitrate was available for organisms," said Xiao. "And then we tie that with the fossil data to show that there's a relationship."

While ancient oceans are long gone, what happened in ancient oceans are recorded in rocks, and studying these rocks provides a link from our Earth's history to the present and to the future.

Read more at Science Daily

Ludwig van Beethoven's genome sheds light on chronic health problems and cause of death

In 1802, Ludwig van Beethoven asked his brothers to request that his doctor, J.A. Schmidt, describe his malady -- his progressive hearing loss -- to the world upon his death so that "as far as possible at least the world will be reconciled to me after my death." Now, more than two centuries later, a team of researchers reporting in the journal Current Biology on March 22 have partially fulfilled his wish by analyzing DNA they lifted and pieced together from locks of his hair.

"Our primary goal was to shed light on Beethoven's health problems, which famously include progressive hearing loss, beginning in his mid- to late-20s and eventually leading to him being functionally deaf by 1818," said Johannes Krause from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

"We were unable to find a definitive cause for Beethoven's deafness or gastrointestinal problems," Krause says. "However, we did discover a number of significant genetic risk factors for liver disease. We also found evidence of an infection with hepatitis B virus in at latest the months before the composer's final illness. Those likely contributed to his death."

As commonly happens when people analyze DNA, the researchers uncovered another surprise. Beethoven's Y chromosome doesn't match that of any of five modern-day relatives carrying the same last name and sharing, on the basis of genealogical records, a common ancestor with Beethoven's paternal line. The finding points to an extramarital "event" somewhere over the generations on Beethoven's father's side.

"This finding suggests an extrapair paternity event in his paternal line between the conception of Hendrik van Beethoven in Kampenhout, Belgium in c.1572 and the conception of Ludwig van Beethoven seven generations later in 1770, in Bonn, Germany," says Tristan Begg, now at the University of Cambridge, U.K.

The idea for the work was conceived by Begg and study co-author William Meredith almost a decade ago. They were motivated by Beethoven's request for postmortem studies to describe his illness and make it public. In the new study, the team, also including Toomas Kivisild of Katholieke Universiteit Leuven in Belgium, relied on recent improvements in ancient DNA analysis; these improvements have enabled whole-genome sequencing from small quantities of historical hair.

First, they analyzed independently sourced locks of hair attributed to Beethoven, only five of which they confirmed came from the same European male. They deemed these five to be "almost certainly authentic" and used them to sequence Beethoven's genome to 24-fold genomic coverage.

Medical biographers had earlier suggested that Beethoven had many substantially heritable health conditions. But the researchers in this study couldn't find in his genome an explanation for Beethoven's hearing disorder or gastrointestinal problems. They did find that he was genetically predisposed to liver disease.

Further study of other DNA in his samples suggested that he also had a hepatitis B infection at least during the months leading up to his death. "Together with the genetic predisposition and his broadly accepted alcohol consumption, these present plausible explanations for Beethoven's severe liver disease, which culminated in his death," they write.

The researchers note that previous analyses suggesting that Beethoven had lead poisoning turned out to have been based on a sample that wasn't Beethoven's at all; instead, it came from a female. Future studies testing for lead, opiates, and mercury must be based on authenticated samples, they say.

Read more at Science Daily

Galaxy changes classification as jet changes direction

A team of international astronomers have discovered a galaxy that has changed classification due to unique activity within its core. The galaxy, named PBC J2333.9-2343, was previously classified as a radio galaxy, but the new research has revealed otherwise. The work is published in Monthly Notices of the Royal Astronomical Society.

PBC J2333.9-2343, located 656 844 372 light years away, has now been classified as a giant radio galaxy that is 4 million light years across and happens to have a blazar in its core; a blazar is an active galactic nucleus (AGN) with a relativistic jet (a jet travelling close to the speed of light) directed towards an observer. Blazars are very high energy objects and are considered to be one of the most powerful phenomena in the Universe. The research has revealed that in PBC J2333.9-2343, the jet changed its direction drastically by an angle of up to 90 degrees, going from being in the plane of the sky, perpendicular to our line of sight, to pointing directly towards us.

A blazar jet is made of elemental charged particles like electrons or protons that move at velocities close to the speed of light. These move in circles around a strong magnetic field, causing the emission of radiation across the entire electromagnetic spectrum. In PBC J2333.9-2343, the jet is thought to originate from or close to the supermassive black hole in its centre.

With the jet pointing in our direction, the emission is strongly enhanced and can easily exceed that coming from the rest of the galaxy. This in turn drives high-intensity flares stronger than those coming from other radio galaxies, thus changing its categorisation.

The orientation of the jets to us determines how a galaxy is classified. When two jets point towards the plane of the sky, they are classified as a radio galaxy, but if one of the jets points towards us, then the AGN of the galaxy is known as a blazar. With jets in the plane of the sky and one directed at us, PBC J2333.9-2343 has been reclassified as a radio galaxy with a blazar at its centre.

Changes in the direction of jets have been described in the past, for example with X-shaped radio galaxies. This is the first time that such a phenomenon has been observed where it does not suggest the presence of two different phases of jet activity from its morphology observed at radio frequencies -- the direction change appears to have taken place in the same nuclear outburst originating from the AGN.

To find out more about this mysterious galaxy, astronomers had to observe it across a wide range of the electromagnetic spectrum. PBC J2333.9-2343 was observed with radio, optical, infrared, x-ray, ultraviolet and gamma ray telescopes. Data was obtained from the German 100m-Radio Telescope Effelsberg at the Max Planck Institute for Radio Astronomy, the Yale University 1.3m-SMARTS optical telescope, and the Penn State Neil Gehrels Swift Observatory.

The team then compared the properties of PBC J2333.9-2343 with large samples of blazars and non-blazar galaxies provided by the ALeRCE (Automatic Learning for the Rapid Classification of Events) project in Chile with data from the Zwicky Transient Facility (ZTF) and the Asteroid Terrestrial-impact Last Alert System (ATLAS).

Using the observational data, the team concluded that this galaxy has a bright blazar in the centre, with two lobes in the outer areas of the jet. The lobes that are observed are related to the old jets and are no longer being fed by the emission from the nucleus, so these lobes are relics of past radio activity. The AGN no longer drives the lobes as seen in typical radio galaxies.

The team do not yet know what caused the drastic change in direction of the jets. They speculate that it could have been a merging event with another galaxy or any other relatively large object, or a strong burst of activity in the galactic nucleus after a dormant period.

Dr Lorena Hernández-García, lead author of the paper and researcher at the Millenium Institute of Astrophysics, says "We started to study this galaxy as it showed peculiar properties. Our hypothesis was that the relativistic jet of its supermassive black hole had changed its direction, and to confirm that idea we had to carry out a lot of observations."

Read more at Science Daily

3000+ billion tons of ice lost from Antarctic Ice Sheet over 25 years

Scientists have calculated that the fastest changing Antarctic region - the Amundsen Sea Embayment - has lost more than 3,000 billion tonnes of ice over a 25-year period.

If all the lost ice was piled on London, it would stand over 2 km tall - or 7.4 times the height of the Shard. If it were to cover Manhattan, it would stand at 61 km - or 137 Empire State Buildings placed on top of one another. 

Twenty major glaciers form the Amundsen Sea Embayment in West Antarctica, which is more than four times the size of the UK, and they play a key role in contributing to the level of the world's oceans.  

So much water is held in the snow and ice, that if it were to all to drain into the sea, global sea levels could increase by more than one metre.  

The research, led by Dr Benjamin Davison at the University of Leeds, calculated the "mass balance" of the Amundsen Sea Embayment. This describes the balance between mass of snow and ice gain due to snowfall and mass lost through calving, where icebergs form at the end of a glacier and drift out to sea.

When calving happens faster than the ice is replaced by snowfall, then the Embayment loses mass overall and contributes to global sea level rise. Similarly, when snowfall supply drops, the Embayment can lose mass overall and contribute to sea level rise.

The results show that West Antarctica saw a net decline of 3,331 billion tonnes of ice between 1996 and 2021, contributing over nine millimetres to global sea levels.  Changes in ocean temperature and currents are thought to have been the most important factors driving the loss of ice. 

Dr Davison, a Research Fellow at the Institute for Climate and Atmospheric Science at Leeds, said: "The 20 glaciers in West Antarctica have lost an awful lot of ice over the last quarter of a century and there is no sign that the process is going to reverse anytime soon although there were periods where the rate of mass loss did ease slightly. 

"Scientists are monitoring what is happening in the Amundsen Sea Embayment because of the crucial role it plays in sea-level rise. If ocean levels were to rise significantly in future years, there are communities around the world who would experience extreme flooding." 

The research has been published in the scientific journal Nature Communications.

Extreme snowfall events

Using climate models that show how air currents move around the world, the scientists identified that the Amundsen Sea Embayment had experienced several extreme snowfall events over the 25-year study period. 

These would have resulted in periods of heavy snowfall and periods of very little snowfall or a "snow drought."  

The researchers factored these extreme events into their calculations. Surprisingly, they found that these events contributed up to half of the ice change at certain times, and therefore played a key role in the contribution the Amundsen Sea Embayment was making to sea level rise during certain time periods.  

For example, between 2009 and 2013, the models revealed a period of a persistant snow drought. The lack of snowfall starved the ice sheet and caused it to lose ice, therefore contributing about 25% more to sea level rise than in years of average snowfall. 

In contrast, during the winters of 2019 and 2020 there was very heavy snowfall. The scientists estimated that this heavy snowfall mitigated the sea level contribution from the Amundsen Sea Embayment, reducing it to about half of what it would have been in an average year.  

Dr Davison said: "Changes in ocean temperature and circulation appear to be driving the long-term, large-scale changes in West Antarctica ice sheet mass.  We absolutely need to research those more because they are likely to control the overall sea level contribution from West Antarctica.  

"However, we were really surprised to see just how much periods of extremely low or high snowfall could affect the ice sheet over two to five-year periods -- so much so that we think they could play an important, albeit secondary role, in controlling rates of West Antarctic ice loss." 

Dr Pierre Dutrieux, a scientist at the British Antarctic Survey and co-author of the study, added: "Ocean temperature changes and glacial dynamics appear strongly connected in this part of the world, but this work highlights the large variability and unexpected processes by which snowfall also plays a direct role in modulating glacier mass."

New glacier named

The ice loss from the region over the past 25 years has seen the retreat of the Pine Island Glacier,  also known as PIG.

As it retreated, one of its tributary glaciers became detached from the main glacier and rapidly accelerated. As a result, the tributary glacier has now been named by the UK Antarctic Place-names Committee, Piglet Glacier, so that it can be unambiguously located and identified by future studies.  

Dr Anna Hogg, one of the authors of the paper and Associate Professor at the Institute of Climate and Atmospheric Science at Leeds, said: "As well as shedding new light on the role of extreme snowfall variability on ice sheet mass changes, this research also provides new estimates of how quickly this important region of Antarctica is contributing to sea level rise.  

"Satellite observations have showed that the newly named Piglet Glacier accelerated its ice speed by 40%, as the larger PIG retreated to its smallest extent since records began."

Read more at Science Daily

Human and ocean health impacts of ocean plastics

For the first time, leading researchers from the fields of healthcare, ocean science, and social science have collaborated to quantify plastic's considerable risks to all life on Earth. The Minderoo-Monaco Commission on Plastics and Human Health report, released today, presents a comprehensive analysis showing plastics as a hazard at every stage of their life cycle.

The report was led by scientists at the Minderoo Foundation, the Centre Scientifique de Monaco, and Boston College. Researchers Mark Hahn and John Stegeman at the Woods Hole Oceanographic Institution (WHOI) were lead authors on a section focusing on the impacts of plastics on the ocean.

The Commission's key findings include:

•     Plastics cause disease, impairment, and premature mortality at every stage of their life cycle, with the health repercussions disproportionately affecting vulnerable, low-income, minority communities, particularly children.
•     Toxic chemicals that are added to plastics and routinely detected in people are, among other effects, known to increase the risk of miscarriage, obesity, cardiovascular disease, and cancers.
•     Plastic waste is ubiquitous in the global environment, with microplastics occurring throughout the ocean and the marine food chain.

"It's only been a little over 50 years since we've been aware of the presence of plastics throughout the ocean," said John Stegeman, a senior scientist the Department of Biology at WHOI. "The Minderoo-Monaco Commission's work is a significant leap forward in connecting the broad health implications of plastics -- to the ocean and to humanity."

The Commission concluded that current plastic production, use, and disposal patterns are not sustainable and are responsible for significant harm to human health, the economy, and the environment -- especially the ocean -- as well as deep societal injustices. Plastics, the report notes, account for an estimated 4 to 5% of all greenhouse gas emissions across their lifecycle, equivalent to emissions from Russia, making them a large-scale contributor to climate change.

The study also calculated the cost of the health repercussions attributed to plastic production to be $250 billion in a 12-month period, which is more than the GDP of New Zealand or Finland in 2015, the year the data were collected. In addition, health care costs associated with chemicals in plastics are estimated to be in the hundreds of billions of dollars. The research also noted that the ubiquity of fast food and discount stores in poorer communities increased exposure to plastic packaging, products, and associated chemicals and impacts.

"Plastic waste endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being," said Dr. Hervé Raps, Physician Delegate for Research at Centre Scientifique de Monaco. "Besides their intrinsic effects, plastics can also be a vector for potentially pathogenic microorganisms and other chemicals adsorbed from polluted water. And alongside the new findings of this report, linking toxic chemicals to human harms, this is not the time to slow down our understanding of impacts in the ocean."

Although plastics' potential harm to human health might be news to some, the oceanographic and marine biology communities have been acutely aware of its negative environmental impacts for decades. Despite this head start, the Commission's findings reveal a pressing need for better understanding and monitoring of the effects of plastics and plastic-associated chemicals on marine species. The authors also highlight a significant lack of knowledge concerning the concentrations of the smallest micro- and nano-plastic particles (MNPs) in the marine environment and their potential impacts on marine animals and ecosystems, from the coasts to the abyss.

As a result of its findings, the Commission urged that a cap on global plastic production be a defining feature of the Global Plastics Treaty currently being negotiated at the UN, and that the Treaty focus beyond marine litter to address the impacts of plastics across their entire life cycle, including the many thousands of chemicals incorporated into plastics and the human health impacts. The positive news is that the Commission reports that many of plastics' harms can be avoided via better production practices, alternative design, less toxic chemicals, and decreased consumption.

"Ocean health is intimately and intricately connected to human health," said Mark Hahn, a senior scientist in the Department of Biology at WHOI. "Our attention now needs to be on creating a broadly acceptable international agreement that addresses the full life cycle of plastics in order to prioritize the health of the ocean that supports us all."

Read more at Science Daily

How the 'marsupial sabertooth' thylacosmilus saw its world

A new study investigates how an extinct, carnivorous marsupial relative with canines so large they extended across the top of its skull could hunt effectively despite having wide-set eyes, like a cow or a horse. The skulls of carnivores typically have forward-facing eye sockets, or orbits, which helps enable stereoscopic (3D) vision, a useful adaptation for judging the position of prey before pouncing. Scientists from the American Museum of Natural History and the Instituto Argentino de Nivología, Glaciología, y Ciencias Ambientales in Mendoza, Argentina, studied whether the "marsupial sabertooth" Thylacosmilus atrox could see in 3D at all. Their results are published today in the journal Communications Biology.

Popularly known as the "marsupial (or metatherian) sabertooth" because its extraordinarily large upper canines recall those of the more famous placental sabertooth that evolved in North America, Thylacosmilus lived in South America until its extinction about 3 million years ago. It was a member of Sparassodonta, a group of highly carnivorous mammals related to living marsupials. Although sparassodont species differed considerably in size -- Thylacosmilus may have weighed as much as 100 kilograms (220 pounds) -- the great majority resembled placental carnivores like cats and dogs in having forward-facing eyes and, presumably, full 3D vision. By contrast, the orbits of Thylacosmilus, a supposed hypercarnivore -- an animal with a diet estimated to consist of at least 70 percent meat -- were positioned like those of an ungulate, with orbits that face mostly laterally. In this situation, the visual fields do not overlap sufficiently for the brain to integrate them in 3D. Why would a hypercarnivore evolve such a peculiar adaptation? A team of researchers from Argentina and the United States set out to look for an explanation.

"You can't understand cranial organization in Thylacosmilus without first confronting those enormous canines," said lead author Charlène Gaillard, a Ph.D. student in the Instituto Argentino de Nivología, Glaciología, y Ciencias Ambientales (INAGLIA). "They weren't just large; they were ever-growing, to such an extent that the roots of the canines continued over the tops of their skulls. This had consequences, one of which was that no room was available for the orbits in the usual carnivore position on the front of the face."

Gaillard used CT scanning and 3D virtual reconstructions to assess orbital organization in a number of fossil and modern mammals. She was able to determine how the visual system of Thylacosmilus would have compared to those in other carnivores or other mammals in general. Although low orbital convergence occurs in some modern carnivores, Thylacosmilus was extreme in this regard: it had an orbital convergence value as low as 35 degrees, compared to that of a typical predator, like a cat, at around 65 degrees.

However, good stereoscopic vision also relies on the degree of frontation, which is a measure of how the eyeballs are situated within the orbits. "Thylacosmilus was able to compensate for having its eyes on the side of its head by sticking its orbits out somewhat and orienting them almost vertically, to increase visual field overlap as much as possible," said co-author Analia M. Forasiepi, also in INAGLIA and a researcher in CONICET, the Argentinian science and research agency. "Even though its orbits were not favorably positioned for 3D vision, it could achieve about 70 percent of visual field overlap -- evidently, enough to make it a successful active predator."

"Compensation appears to be the key to understanding how the skull of Thylacosmilus was put together," said study co-author Ross D. E. MacPhee, a senior curator at the American Museum of Natural History. "In effect, the growth pattern of the canines during early cranial development would have displaced the orbits away from the front of the face, producing the result we see in adult skulls. The odd orientation of the orbits in Thylacosmilus actually represents a morphological compromise between the primary function of the cranium, which is to hold and protect the brain and sense organs, and a collateral function unique to this species, which was to provide enough room for the development of the enormous canines."

Lateral displacement of the orbits was not the only cranial modification that Thylacosmilus developed to accommodate its canines while retaining other functions. Placing the eyes on the side of the skull brings them close to the temporal chewing muscles, which might result in deformation during eating. To control for this, some mammals, including primates, have developed a bony structure that closes off the eye sockets from the side. Thylacosmilus did the same thing -- another example of convergence among unrelated species.

This leaves a final question: What purpose would have been served by developing huge, ever-growing teeth that required re-engineering of the whole skull?

"It might have made predation easier in some unknown way," said Gaillard, "But, if so, why didn't any other sparassodont -- or for that matter, any other mammalian carnivore -- develop the same adaptation convergently? The canines of Thylacosmilus did not wear down, like the incisors of rodents. Instead, they just seem to have continued growing at the root, eventually extending almost to the rear of the skull."

Read more at Science Daily

New evidence: Immune system cells in the gut linked to stress-induced depression

In experiments with mice and humans, a team led by Johns Hopkins Medicine researchers says it has identified a particular intestinal immune cell that impacts the gut microbiome, which in turn may affect brain functions linked to stress-induced disorders such as depression. Targeting changes mediated by these immune cells in the gut, with drugs or other therapies, could potentially bring about new ways to treat depression.

The findings of the study were published March 20, 2023 in the journal Nature Immunology.

"The results of our study highlight the previously unrecognized role of intestinal gamma delta T cells (γδ T cells) in modifying psychological stress responses, and the importance of a protein receptor known as dectin-1, found on the surface of immune cells, as a potential therapeutic target for the treatment of stress-induced behaviors," says Atsushi Kamiya, M.D., Ph.D., professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine and the study's senior author.

Dectin-1 binds to certain antigens, or proteins, to signal immune cells to activate in specific ways. This receptor, the researchers say, may be involved in the microbiome alteration and immune-inflammatory responses in the colon of mice, which suggests that it may be involved in stress responses via γδ T cells in the intestinal immune system.

On the basis of previous studies suggesting that immune inflammatory responses in the gut are related to depression, Kamiya and his team designed experiments to focus on understanding stress-induced behaviors produced by an imbalance in the gut microbiota -- types of microorganisms found in a specific environment, such as bacteria, fungi and viruses.

To this end, the team examined the effects of chronic social defeat stress (CSDS) on the gut microbiota in mice. CSDS is a standard rodent test to study stress-induced disorders such as depression. In a series of experiments, the researchers simulated potential stress inducing environments that could mimic similar responses in human environments. After each exposure, the mice were assessed and classified as stress-resilient (stress did not diminish social interactions) or stress-susceptible (stress increased social avoidance).

Fecal samples were then collected and put through genetic analysis to identify the diversity of bacteria in the gut microbiota of the mice. The analysis showed that the intestinal organisms were less diverse in stress-susceptible mice than in stress-resilient mice. It specifically revealed that there were less Lactobacillus johnsonii (L. johnsonii) -- a type of probiotic, or "good" bacteria -- in stress-susceptible mice compared to stress-resilient mice.

"We found that stress increased the γδ T cells, which in turn increased social avoidance," says Xiaolei Zhu, M.D., Ph.D., assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine and the study's lead author. "However, when the stressed mice were given L. johnsonii, social avoidance decreased and the γδ T cells went to normal levels, suggesting that CSDS-induced social avoidance behavior may be the result of lower levels of the bacteria and γδ T cell changes."

Looking for potential natural approaches for prevention of depression rooted somehow in the gut, the researchers explored how changes in dectin-1 on CSDS-induced elevation of γδ T cells responded to pachyman. A compound extracted from wild mushrooms, pachyman is used as a natural anti-inflammatory agent and for treating depression in Eastern medicine. For this experiment, mice were fed a dose of pachyman, which was shown in previous research to affect immune function. Data from flow cytometry analysis -- a technology used to measure the physical and chemical characteristics of a population of cells -- provided evidence that dectin-1 binds to pachyman, inhibiting CSDS-induced γδ17 T cell activity and easing social avoidance behavior.

To gain insight into how the alterations in the gut microbiota could impact the human brain, the researchers investigated the makeup of gut organisms in people with major depressive disorder (MDD) compared to people without MDD. From June 2017 to September 2020, 66 participants, ages 20 or older, were recruited at Showa University Karasuyama Hospital, Keio University Hospital and Komagino Hospital in Tokyo, Japan. Of the study participants, 32 had MDD (17 women and 15 men). The other 34 participants (18 women and 16 men) who did not have MDD formed the control group.

Stool samples were collected from all study participants, who had comprehensive evaluations including psychiatric history and standard screening assessments for depression and anxiety. In these assessments, higher scores indicate greater depressive symptoms. Genetic analysis of the stool samples showed no difference in the diversity of intestinal bacteria between the subjects with MDD and the control group. However, the relative abundance of Lactobacillus was inversely related to higher depression and anxiety scores in the MDD group, meaning that the more Lactobacillusfound in the gut, the lower the potential for depression and anxiety, the researchers say.

"Despite the differences of intestinal microbiota between mice and humans, the results of our study indicate that the amount of Lactobacillus in the gut may potentially influence stress responses and the onset of depression and anxiety," says Kamiya.

The investigators say more research is needed to further understand how γδ T cells in the intestinal immune system may impact the neurological functions in the brain and the role of dectin-1 in other cell types along the gut-brain connection under stress conditions.

"These early-stage findings show that, in addition to probiotic supplements, targeting drugs to such types of receptors in the gut immune system may potentially yield novel approaches to prevent and treat stress-induced psychiatric symptoms such as depression," says Kamiya.

Read more at Science Daily

Fossil site is 'Rosetta Stone' for understanding early life

Leading edge technology has uncovered secrets about a world-renowned fossil hoard that could offer vital clues about early life on earth.

Researchers who analysed the 400 million-year-old-cache, found in rural north-east Scotland, say their findings reveal better preservation of the fossils at a molecular level than was previously anticipated.

Fresh scrutiny of the exquisitely preserved treasure trove from Aberdeenshire has enabled scientists to identify the chemical fingerprints of the various organisms within it.

Just as the Rosetta Stone helped Egyptologists translate hieroglyphics, the team hopes these chemical codes can help them decipher more about the identity of the life forms, that other more ambiguous fossils represent.

The spectacular fossil ecosystem near the Aberdeenshire village of Rhynie was discovered in 1912, mineralised and encased by chert -- hard rock composed of silica.Known as the Rhynie chert, it originates from the Early Devonian period -- about 407 million years ago -- and has a significant role to play in scientists understanding of life on earth.

Researchers combined the latest non-destructive imaging with data analysis and machine learning to analyse fossils from collections held by National Museums Scotland and the Universities of Aberdeen and Oxford.Scientists from the University of Edinburgh were able to probe deeper than has previously been possible, which they say could reveal new insights about less well-preserved samples.

Employing a technique known as FTIR spectroscopy -- in which infrared light is used to collect high-resolution data -- researchers found impressive preservation of molecular information within the cells, tissues and organisms in the rock.

Since they already knew which organisms most of the fossils represented, the team was able to discover molecular fingerprints that reliably discriminate between fungi, bacteria and other groups.

These fingerprints were then used to identify some of the more mysterious members of the Rhynie ecosystem, including two specimens of an enigmatic tubular "nematophyte."

These strange organisms, which are found in Devonian -- and later Silurian -- sediments have both algal and fungal characteristics and were previously hard to place in either category. The new findings indicate that they were unlikely to have been either lichens or fungi.

Dr Sean McMahon, Chancellor's Fellow from the University of Edinburgh's School of Physics and Astronomy and School of GeoSciences, said: "We have shown how a quick, non-invasive method can be used to discriminate between different lifeforms, and this opens a unique window on the diversity of early life on Earth."

The team fed their data into a machine learning algorithm that was able to classify the different organisms, providing the potential for sorting other datasets from other fossil-bearing rocks.

The study, published in Nature Communications, was funded by The Royal Society, Wallonia-Brussels International and the National Council of Science and Technology of Mexico.

Dr Corentin Loron, Royal Society Newton International Fellow from the University of Edinburgh's School of Physics and Astronomy said the study shows the value of bridging palaeontology with physics and chemistry to create new insights into early life.

"Our work highlights the unique scientific importance of some of Scotland's spectacular natural heritage and provides us with a tool for studying life in trickier, more ambiguous remnants," Dr Loron said.

Read more at Science Daily

Genome research: Origin and evolution of vine

Cultivation and growth of grapevines have strongly influenced European civilizations, but where the grapevine comes from and how it has spread across the globe has been highly disputed so far. In an extensive genome project, researchers from the Chinese Yunnan Agricultural University have determined its origin and evolution from the wild vine to today's cultivar by analyzing thousands of vine genomes collected along the Silk Road from China to Western Europe. The collection of wild vines of Karlsruhe Institute of Technology (KIT) played an important role in the above project.

Grapevine is among the world's oldest crops. Wine was one of the oldest products traded all around the world. It pushed the exchange of cultures, ideas, and religions. At the end of the Ice Age, grapevine originated from the European wild vine, of which only a few relic populations have survived to date.

One of these populations can be found on the Ketsch peninsula on the Rhine river between Karlsruhe and Mannheim. So far, the traces of when and where exactly wild vines were domesticated, of whether grapes for wine production and table grapes have the same origin, and how thousands of vines developed have been hidden in the mist of the prehistoric era. Still, it is clear that grapevine survived partly drastic climate changes and gathered a number of genes from Asia as a result of early human migration movements. "For some years now, it has been known that today's Silk Road once was a wine road.

The Chinese symbol for alcohol is derived from Georgian wine jugs, so-called Qevri," explains Professor Peter Nick of KIT's Joseph-Gottlieb Kölreuter Institut for Plant Sciences (JKIP). Nick, who had already cooperated with Chinese researchers in a previous project to determine grapevine genomes, suggested to collect grapevines along the previous Silk Road and to analyze their genomes.

Most Detailed Model of the Evolution and Domestication of Grapevine So Far

Nick's idea gave rise to a network of researchers from 16 countries, who contributed not only wild vines and old species from their regions, but also knowledge on their origin and history. Under most difficult circumstances resulting from the global political situation, DNA samples of more than 3500 vines, including more than 1000 wild species, were sent to the State Key Laboratory for Conservation and Utilization of Bio-Resources of Yunnan Agricultural University. There, the genomes were decoded under the direction of Dr. Wei Chen and the most detailed model of the evolution and domestication of grapevines so far was generated. As a result, a number of new findings have been obtained. Now, the origin of winegrowing can be dated back to earlier than 11,000 B.C. in the South Caucasus. This means that wine is older than bread. Winegrowing technology very quickly spread across the Mediterranean to the west. Within shortest terms, cross-breeding with local wild vines produced a large variety of vines that were reproduced using cuttings. About 7000 years ago in the Middle East, large-berry species developed to table vines.

Read more at Science Daily

Ultrafast beam-steering breakthrough

In a major breakthrough in the fields of nanophotonics and ultrafast optics, a Sandia National Laboratories research team has demonstrated the ability to dynamically steer light pulses from conventional, so-called incoherent light sources.

This ability to control light using a semiconductor device could allow low-power, relatively inexpensive sources like LEDs or flashlight bulbs to replace more powerful laser beams in new technologies such as holograms, remote sensing, self-driving cars and high-speed communication.

"What we've done is show that steering a beam of incoherent light can be done," said Prasad Iyer, Sandia scientist and lead author of the research, which was reported in the current issue of the journal Nature Photonics. The work was funded by the Department of Energy's Office of Science.

Incoherent light is emitted by many common sources, such as an old-fashioned incandescent light bulb or an LED bulb. This light is called incoherent since the photons are emitted with different wavelengths and in a random fashion. A beam of light from a laser, however, does not spread and diffuse because the photons have the same frequency and phase and is thus called coherent light.

In the team's research, they manipulated incoherent light by using artificially structured materials called metasurfaces, made from tiny building blocks of semiconductors called meta-atoms that can be designed to reflect light very efficiently. Although metasurfaces had previously shown promise for creating devices that could steer light rays to arbitrary angles, they also presented a challenge because they had only been designed for coherent light sources. Ideally, one would want a semiconductor device that can emit light like an LED, steer the light emission to a set angle by applying a control voltage and shift the steering angle at the fastest speed possible.

The researchers started with a semiconductor metasurface that had embedded tiny light sources called quantum dots. By using a control optical pulse, they were able to change, or reconfigure, the way the surface reflected light and steer the light waves emitted from the quantum dots in different directions over a 70-degree range for less than a trillionth-of-a-second, marking a significant success. Similar to laser-based steering, the steered beam restrained the tendency of incoherent light to spread over a wider viewing angle and instead produced bright light at a distance.

Taming light

A feat previously considered impossible, the team's proof-of-principle work paves the way for developments in the fields of nanophotonics and ultrafast optics. The ability to dynamically control incoherent light sources and manipulate their properties offers a wide range of applications.

One low-power use would be to brighten military helmet screens used to overlay maps or blueprints over ordinary vision. "In applications where space is valuable," Iyer said, "steering light emission with low-size-and-weight metasurface-LED displays could be made possible in the future with this technology. We can use the light emitted in a better way rather than just turning them off and on."

The technique could also provide a new kind of small display that can project holographic images onto eyeballs using low-power LEDs, a capability of particular interest for augmented and virtual reality devices. Other uses could be in self-driving cars where LIDAR is used to sense objects in the path of the car.

In terms of expressions of interest, the team has had several inquiries from commercial sources, said Sandia researcher Igal Brener, a paper author and lead scientist on the project. "A commercial product could be 5-10 years out, especially if we want to have all the functionality on-chip," Brener said. "You wouldn't use a control optical pulse to impart the changes in the metasurface needed to steer the light, but rather you would do this control electrically. We have ideas and plans, but it's still early. Imagine an LED light bulb that can emit light to follow you. Then you wouldn't waste all that illumination where there's nobody. This is one of the many applications that we dreamed about with DOE years ago for energy efficiency for office lighting, for example."

Similarly, tamed light may one day offer benefits in scenarios where focused illumination is only needed in a specific area of interest, such as surgery or in autonomous vehicles.

Read more at Science Daily

Remains of a modern glacier found near Mars' equator implies water ice possibly present at low latitudes on Mars even today

In a groundbreaking announcement at the 54th Lunar and Planetary Science Conference held in The Woodlands, Texas, scientists revealed the discovery of a relict glacier near Mars' equator. Located in Eastern Noctis Labyrinthus at coordinates 7° 33' S, 93° 14' W, this finding is significant as it implies the presence of surface water ice on Mars in recent times, even near the equator. This discovery raises the possibility that ice may still exist at shallow depths in the area, which could have significant implications for future human exploration.

The surface feature identified as a "relict glacier" is one of many light-toned deposits (LTDs) found in the region. Typically, LTDs consist mainly of light-colored sulfate salts, but this deposit also shows many of the features of a glacier, including crevasse fields and moraine bands. The glacier is estimated to be 6 kilometers long and up to 4 kilometers wide, with a surface elevation ranging from +1.3 to +1.7 kilometers. This discovery suggests that Mars' recent history may have been more watery than previously thought, which could have implications for understanding the planet's habitability.

"What we've found is not ice, but a salt deposit with the detailed morphologic features of a glacier. What we think happened here is that salt formed on top of a glacier while preserving the shape of the ice below, down to details like crevasse fields and moraine bands," said Dr. Pascal Lee, a planetary scientist with the SETI Institute and the Mars Institute, and the lead author of the study.

The presence of volcanic materials blanketing the region hints of how the sulfate salts might have formed and preserved a glacier's imprint underneath. When freshly erupted pyroclastic materials (mixtures of volcanic ash, pumice, and hot lava blocks) come in contact with water ice, sulfate salts like the ones commonly making up Mars' light-toned deposits may form and build up into a hardened, crusty salt layer.

"This region of Mars has a history of volcanic activity. And where some of the volcanic materials came in contact with glacier ice, chemical reactions would have taken place at the boundary between the two to form a hardened layer of sulfate salts," explains Sourabh Shubham, a graduate student at the University of Maryland's Department of Geology, and a co-author of the study. "This is the most likely explanation for the hydrated and hydroxylated sulfates we observe in this light-toned deposit."

Over time, with erosion removing the blanketing volcanic materials, a crusty layer of sulfates mirroring the glacier ice underneath became exposed, which would explain how a salt deposit is now visible, presenting features unique to glaciers such as crevasses and moraine bands.

"Glaciers often present distinctive types of features, including marginal, splaying, and tic-tac-toe crevasse fields, and also thrust moraine bands and foliation. We are seeing analogous features in this light-toned deposit, in form, location, and scale. It's very intriguing," said John Schutt, a geologist at the Mars Institute, experienced icefield guide in the Arctic and Antarctica, and a co-author of this study.

The glacier's fine-scale features, its associated sulfate salts deposit, and the overlying volcanic materials are all very sparsely cratered by impacts and must be geologically young, likely Amazonian in age, the latest geologic period which includes modern Mars. "We've known about glacial activity on Mars at many locations, including near the equator in the more distant past. And we've known about recent glacial activity on Mars, but so far, only at higher latitudes. A relatively young relict glacier in this location tells us that Mars experienced surface ice in recent times, even near the equator, which is new," said Lee.

It remains to be seen whether water ice might still be preserved underneath the light-toned deposit or if it has disappeared entirely. "Water ice is, at present, not stable at the very surface of Mars near the equator at these elevations. So, it's not surprising that we're not detecting any water ice at the surface. It is possible that all the glacier's water ice has sublimated away by now. But there's also a chance that some of it might still be protected at shallow depth under the sulfate salts."

The study draws an analogy with the ancient ice islands on salt lakebeds, or salars, of the Altiplano in South America. There, old glacier ice has remained protected from melting, evaporation, and sublimation underneath blankets of bright salts. Lee and his co-authors hypothesize a similar situation to explain how sulfate salts on Mars might be able to offer protection to otherwise sublimation-vulnerable ice at low latitudes on the planet.

If there is still water ice preserved at shallow depths at a low latitude on Mars, there would be implications for science and human exploration. "The desire to land humans at a location where they might be able to extract water ice from the ground has been pushing mission planners to consider higher latitude sites. But the latter environments are typically colder and more challenging for humans and robots. If there were equatorial locations where ice might be found at shallow depth, then we'd have the best of both environments: warmer conditions for human exploration and still access to ice," said Lee.

Read more at Science Daily

Stressed out: Mapping the human footprint on coastal areas globally

A global mapping project led by University of Queensland researchers has revealed the major stressors placed upon global coastlines by human activity.

The team quantified and mapped the presence and extent of major land-based and marine stressors, finding that 97 per cent of coastal areas globally had at least one major stressor present.

Professor Salit Kark from UQ's School of Biological Sciences said the research team were surprised at the sheer extent and far-reaching impact revealed by the footprint map created.

"There is hardly anywhere on the planet, outside of the polar and arctic regions, that does not show some form of human pressure on their coastline," Professor Kark said.

"In essence, we have influenced the majority of coastal areas globally.

"We therefore should aim to map and understand our impacts, and also leave some untouched coastlines."

UQ PhD candidate Hannah Allan said the research outlined the spatial extent and magnitude of 10 major land-based stressors and 10 major marine stressors that occur across coastlines globally.

"The threats human activity pose to coastal ecosystems and biodiversity come from both the land and sea, sometimes arriving far from human activity," Ms Allan said.

"Therefore, coastal conservation must incorporate land-sea connections.

"Human population size, tourism, and roads were some of the biggest contributors to the terrestrial component of Australia's coastal human footprint.

"As for marine stressors, increasing sea surface temperatures, nutrient pollution, and shipping were found to be major drivers of human pressure on Australian coastlines."

Professor Noam Levin said a map of this kind, which assembles both terrestrial and marine stressors and presents the coastal human footprint globally, has rarely been attempted.

"This research offers valuable insights that could help decision-makers and managers identify where to mitigate particular impacts," Prof. Levin said.

"For example, the database underlying the human footprint can show specific areas with high oil and gas operations, such as in Western Australia.

"This can help develop preparedness procedures for the very realistic chance of environmental disasters that impact coastal areas, such as oil spills.

"An added benefit of our new global map is that it helps prioritise these decisions based on how widespread the potential pressures of our human footprint in certain areas of the world might be.

"Coastal areas, where 90 per cent of Australians live, were not immune to these stressors.

"For Australia, the highest human footprint was found in the coastal cities, in the order of Melbourne, Sydney, Perth, Adelaide, and Brisbane.

"We also mapped 160 areas on the planet with the most pristine coastal areas, including several in Australia.

"Of those, nearly 40 per cent were totally unprotected -- opening an opportunity to identify coastal areas for further conservation actions.

"A key finding was that light pollution is increasing, with more white LEDs being used, placing great strain on areas of high importance for biodiversity, disrupting the natural patterns of wildlife."

Moving forward, researchers are looking to fine-tune the mapping process, looking more specifically at Australia's coastlines.

Read more at Science Daily

Cans or bottles: What's better for a fresh, stable beer?

The flavor of beer begins to change as soon as it's packaged, prompting a debate among afficionados: Does the beverage stay fresher in a bottle or a can? Now, researchers report in ACS Food Science & Technology that the answer is, well, complicated, and depends on the type of beer. An amber ale stayed fresher in bottles, whereas container choice made much less difference to the stability of an India Pale Ale (IPA).

In addition to water and ethanol, beer contains thousands of flavor compounds, which are metabolites produced by yeast, hops and other ingredients. During storage, chemical reactions break down some of those components while forming others. This reduces the content of some tasty flavors while generating unappetizing ones, contributing to the aging, or staling, of beer. To help brewers prolong shelf life, researchers have studied beer aging, but they've concentrated on light lagers and a limited group of chemicals. Jessica Prenni and colleagues wanted to extend that work to amber ale and IPA, as well as additional compounds. The team also wanted to conduct the first stability comparison of beer packaged in glass bottles versus aluminum cans.

Cans and brown bottles of amber ale and IPA were chilled for a month and then kept at room temperature for five months to mimic typical storage conditions. Every two weeks, the researchers analyzed the metabolites in newly opened containers. Throughout this time, the concentration of certain metabolites in amber ale -- including some amino acids and esters -- differed significantly depending on whether it was packaged in a bottle or can. IPA, however, was much less sensitive to packaging type, possibly because of its higher concentration of polyphenols from hops. These compounds not only prevent oxidation but also bind to amino acids, thus retaining them in the beer rather than allowing them to get stuck to the inside of a container.

The researchers also found that the metabolic profile of both amber ale and IPA changed over time, whether packaged in a can or bottle. However, amber ale in cans showed the greatest variation during aging. Once scientists find out how all of these changes affect flavor, brewers will be able to make more-informed decisions about the best type of packaging for their particular type of beer.

From Science Daily

First detection of neutrinos made at a particle collider

A team including physicists of the University of Bern has for the first time detected subatomic particles called neutrinos created by a particle collider, namely at CERN's Large Hadron Collider (LHC). The discovery promises to deepen scientists' understanding of the nature of neutrinos, which are among the most abundant particles in the universe and key to the solution of the question why there is more matter than antimatter.

Neutrinos are fundamental particles that played an important role in the early phase of the universe. They are key to learn more about the fundamental laws of nature, including how particles acquire mass and why there is more matter than antimatter. Despite being among the most abundant particles in the universe they are very difficult to detect because they pass through matter with almost no interaction. They are therefore often called "ghost particles."

Neutrinos have been known for several decades and were very important for establishing the standard model of particle physics. But most neutrinos studied by physicists so far have been low-energy neutrinos. Previously, no neutrino produced at a particle collider had ever been detected by an experiment. Now, an international team including researchers from the Laboratory for High Energy Physics (LHEP) of the University of Bern has succeeded in doing just that. Using the FASER particle detector at CERN in Geneva, the team was able to detect very high energy neutrinos produced by brand a new source: CERN's Large Hadron Collider (LHC). The international FASER collaboration announced this result on March 19 at the MORIOND EW conference in La Thuile, Italy.

FASER enables investigation of high energy neutrinos

The properties of neutrinos have been studied in numerous experiments since their discovery in 1956 by Clyde L. Cowan and Frederick Reines. One of the leading experiments to study neutrinos is the Deep Underground Neutrino Experiment (DUNE) being built in the USA. The University of Bern is a key contributor. Experiments like DUNE are general purpose and can study many properties of neutrinos from a variety of sources. One aspect that is not covered is very high energy neutrinos.

The highest energy accelerator available is the LHC at CERN, where new particles are produced by two beams of protons smashing together at extremely high energy. However, neutrinos have never been detected at any collider because they escape the existing detectors at the LHC.

The FASER experiment was proposed to fill this gap. "In this experiment we measure very high energy neutrinos produced by the LHC collider at CERN. The goal is to study how these neutrinos are produced, what their properties are and to look for signals of new particles," says Akitaka Ariga, leader of the FASER group at University of Bern's Laboratory for High Energy Physics (LHEP). The LHEP is part of the Physics Institute and of the Albert Einstein Center for Fundamental Physics (AEC). "The FASER experiment is a unique idea at the interface between the highest energy colliders and neutrino physics. Often new discoveries are made when taking such new approaches," says Michele Weber, director of the LHEP of the University of Bern.

Hidden physics in neutrinos?

For the current observation of neutrinos, the experiment took data at the LHC in 2022. The team detected 153 events that are neutrino interactions with extremely high certainty. The neutrinos detected by FASER are of the highest energy ever produced in a lab and are similar to the neutrinos coming from deep-space that trigger dramatic particle showers in our atmosphere or the earth. They are therefore also an important tool to researchers for better understanding observations in particle astrophysics.

"This achievement is a historical milestone for obtaining a new neutrino source with unexplored features," says Akitaka Ariga. The presented result is just the very beginning of a series of explorations. The experiment will continue to take data till the end of 2025. "There might be hidden physics in neutrinos at high energy scale," says Akitaka Ariga.

Read more at Science Daily