NASA's Webb Telescope reaches major milestone as mirror unfolds

NASA's James Webb Space Telescope team fully deployed its 21-foot, gold-coated primary mirror, successfully completing the final stage of all major spacecraft deployments to prepare for science operations.

A joint effort with the European Space Agency (ESA) and Canadian Space Agency, the Webb mission will explore every phase of cosmic history -- from within our solar system to the most distant observable galaxies in the early universe.

"Today, NASA achieved another engineering milestone decades in the making. While the journey is not complete, I join the Webb team in breathing a little easier and imagining the future breakthroughs bound to inspire the world," said NASA Administrator Bill Nelson. "The James Webb Space Telescope is an unprecedented mission that is on the precipice of seeing the light from the first galaxies and discovering the mysteries of our universe. Each feat already achieved and future accomplishment is a testament to the thousands of innovators who poured their life's passion into this mission."

The two wings of Webb's primary mirror had been folded to fit inside the nose cone of an Arianespace Ariane 5 rocket prior to launch. After more than a week of other critical spacecraft deployments, the Webb team began remotely unfolding the hexagonal segments of the primary mirror, the largest ever launched into space. This was a multi-day process, with the first side deployed Jan. 7 and the second Jan. 8.

Mission Operations Center ground control at the Space Telescope Science Institute in Baltimore began deploying the second side panel of the mirror at 8:53 a.m. EST. Once it extended and latched into position at 1:17 p.m. EST, the team declared all major deployments successfully completed.

The world's largest and most complex space science telescope will now begin moving its 18 primary mirror segments to align the telescope optics. The ground team will command 126 actuators on the backsides of the segments to flex each mirror -- an alignment that will take months to complete. Then the team will calibrate the science instruments prior to delivering Webb's first images this summer.

"I am so proud of the team -- spanning continents and decades -- that delivered this first-of-its kind achievement," said Thomas Zurbuchen, associate administrator for the Science Mission Directorate in NASA Headquarters in Washington. "Webb's successful deployment exemplifies the best of what NASA has to offer: the willingness to attempt bold and challenging things in the name of discoveries still unknown."

Soon, Webb will also undergo a third mid-course correction burn -- one of three planned to place the telescope precisely in orbit around the second Lagrange point, commonly known as L2, nearly 1 million miles from Earth. This is Webb's final orbital position, where its sunshield will protect it from light from the Sun, Earth, and Moon that could interfere with observations of infrared light. Webb is designed to peer back over 13.5 billion years to capture infrared light from celestial objects, with much higher resolution than ever before, and to study our own solar system as well as distant worlds.

"The successful completion of all of the Webb Space Telescope's deployments is historic," said Gregory L. Robinson, Webb program director at NASA Headquarters. "This is the first time a NASA-led mission has ever attempted to complete a complex sequence to unfold an observatory in space -- a remarkable feat for our team, NASA, and the world."

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Tipping point in Humboldt Current off Peru leads to species shift

Fundamental changes in the ocean, such as warming, acidification or oxygen depletion, may have significant consequences for the composition of fish stocks, including the displacement of individual species. Researchers at Kiel University (CAU), together with colleagues from Germany, Canada, the USA, and France, have reconstructed environmental conditions of the warm period 125,000 years ago (Eemian interglacial) using sediment samples from the Humboldt Current System off Peru. They were able to show that, at warmer temperatures, mainly smaller, goby-like fish species became dominant and pushed back important food fish such as the anchovy (Engraulis ringens). The trend is independent of fishing pressure and fisheries management. According to the study, the greater warming of the Humboldt Current System as result of climate change has more far-reaching implications for the ecosystem and the global fishing industry than previously thought. The findings appeared in the journal Science, January 7.

The sea off the west coast of South America is one of the most vital and productive fishing grounds on earth. Around eight percent of the global catch of marine species comes from the areas off the coasts of Peru, where the near-surface Humboldt Current provides a high nutrient supply and thus sufficient food for commercially exploited fish species such as the anchovy. Ten percent of the total global catch of anchovies alone comes from the region. Much of it is processed into fish meal and oil and used primarily for aquacultures in China and Norway. However, catches of anchovy in the Humboldt upwelling system are currently declining. The causes of species shifts are mainly due to climate change according to the results of the new study.

Researchers from the Institute of Geosciences at Kiel University, together with colleagues from GEOMAR Helmholtz Centre for Ocean Research and international partners, have for the first time investigated the relationships between temperature, oxygen, nutrient supply and the occurrence of individual fish species using paleo-oceanographic data from the Humboldt Current region. The scientists focused on the warm period about 125,000 years ago (Eemian interglacial). During this time, conditions were similar to those predicted by climate projections (e.g., the IPCC report) for the end of the 21st century at the latest: comparable primary production but water temperatures two degrees Celsius higher than today and increased oxygen deficiency in mid-depth water masses.

For their paleo-oceanographic studies, the researchers at Kiel University primarily analyzed small fish vertebrae that they were able to isolate from the sediment cores. According to the results, smaller, goby-like fish predominated in coastal waters during the ancient warm period, while anchovies made up only a small proportion. Fish with smaller body sizes can adapt better to warmer temperatures. They retain their high activity even in less oxygenated waters thanks to their larger gill surface area relative to their body volume.

"The conditions of this past warm period that we were able to reconstruct from our samples can definitely be compared to the current development and put in context with future scenarios," says first author of the study, Dr. Renato Salvatteci, who is currently working at the Center for Ocean and Society of the Kiel Marine Science (KMS) priority research area at Kiel University and in the BMBF-funded Humboldt-Tipping project. "According to this, there is a clear regime shift towards smaller fish that feel more comfortable in the warm, lower-oxygen conditions. We conclude from our results that the effects of human-induced climate change may have a stronger influence on the evolution of stocks in the region than previously thought," Salvatteci added. Smaller fish are harder to catch and less palatable. According to the report, the impact on the Peru region, local fisheries income and global trade in anchovies could be far-reaching -- potentially affecting global food security.

"Our studies using sediment cores can give us fairly accurate information about the changes and their dynamics in highly productive coastal waters around the world that have occurred in the wake of different climate states and over different time scales," explains Professor Ralph Schneider, a paleoclimate researcher at the Institute of Geosciences at Kiel University and co-author of the study.

The results indicate that due to increasing warming in the Humboldt Current upwelling area, the ecosystem is heading towards a tipping point beyond which anchovy will begin to retreat and not continue to dominate nearshore fishing grounds. "Despite a flexible, sustainable and adaptive management strategy, anchovy biomass and landings have declined, suggesting that we are closer to the ecological tipping point than suspected," summarizes lead author Renato Salvatteci.

The results of the study help to better assess the extent to which a warming ocean can provide sufficient food for the world's population and what changes should be expected for the development of important fish species such as the anchovy.

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Astronomers capture red supergiant’s death throes

For the first time ever, astronomers have imaged in real time the dramatic end to a red supergiant's life -- watching the massive star's rapid self-destruction and final death throes before collapsing into a type II supernova.

Led by researchers at Northwestern University and the University of California, Berkeley (UC Berkeley), the team observed the red supergiant during its last 130 days leading up to its deadly detonation.

The discovery defies previous ideas of how red supergiant stars evolve right before exploding. Earlier observations showed that red supergiants were relatively quiescent before their deaths -- with no evidence of violent eruptions or luminous emissions. The new observations, however, detected bright radiation from a red supergiant in the final year before exploding. This suggests at least some of these stars must undergo significant changes in their internal structure, which then result in the tumultuous ejection of gas moments before they collapse.

"This is a breakthrough in our understanding of what massive stars do moments before they die," said Wynn Jacobson-Galán, the study's lead author. "Direct detection of pre-supernova activity in a red supergiant star has never been observed before in an ordinary type II supernova. For the first time, we watched a red supergiant star explode."

The discovery was published today (Jan. 6) in The Astrophysical Journal.

Although the work was conducted at Northwestern, where Jacobson-Galán was a National Science Foundation (NSF) Graduate Research Fellow, he has since moved to UC Berkeley. Northwestern co-authors include Deanne Coppejans, Charlie Kilpatrick, Giacomo Terreran, Peter Blanchard and Lindsay DeMarchi, who are all members of Northwestern's Center for Interdisciplinary and Exploratory Research in Astrophysics (CIERA).

'We've never confirmed such violent activity'

The University of Hawai?i Institute for AstronomyPan-STARRS on Haleakal?, Maui, first detected the doomed massive star in summer 2020 via the huge amount of light radiating from the red supergiant. A few months later, in fall of 2020, a supernova lit the sky.

The team quickly captured the powerful flash and obtained the very first spectrum of the energetic explosion, named supernova 2020tlf (SN 2020tlf) using the W.M. Keck Observatory's Low Resolution Imaging Spectrometer on Maunakea, Hawai?i. The data showed direct evidence of dense circumstellar material surrounding the star at the time of explosion, likely the same gas that Pan-STARRS had imaged the red supergiant star violently ejecting earlier in the summer.

"It's like watching a ticking time bomb," said Raffaella Margutti, an adjunct associate professor at CIERA and the paper's senior author. "We've never confirmed such violent activity in a dying red supergiant star where we see it produce such a luminous emission, then collapse and combust, until now."

The team continued to monitor SN 2020tlf after the explosion. Based on data obtained from Keck Observatory's Deep Imaging and Multi-Object Spectrograph and Near Infrared Echellette Spectrograph, the researchers determined SN 2020tlf's progenitor red supergiant star -- located in the NGC 5731 galaxy about 120 million light-years away from Earth -- was 10 times more massive than the sun.

Remote possibilities

Margutti and Jacobson-Galán conducted most of the study during their time at Northwestern, with Margutti serving as an associate professor of physics and astronomy and member of CIERA, and Jacobson-Galán as a graduate student in Margutti's research group. Margutti is now an associate professor of astronomy and astrophysics at UC Berkeley.

Northwestern's remote access to Keck Observatory's telescopes was integral to their research. From the University's Evanston campus, astronomers can connect with an on-site telescope operator in Hawai?iand choose where to position the telescope. By bypassing long-distance travel to Hawai?i, astronomers save precious observing time -- often catching transient events like supernovas, which can quickly flare up and then swiftly vanish.

"This significant discovery of a red supergiant supernova is yet one more strong indication of the importance of Northwestern's investment in access to top private telescope facilities, including the Keck Observatory," said Vicky Kalogera, the Daniel I. Linzer Distinguished University Professor of Physics and Astronomy at Northwestern's Weinberg College of Arts and Sciencesand director of CIERA. "The Keck telescopes, currently the best on our planet, uniquely enable scientific advances of this caliber as CIERA researchers have shown since our Keck partnership started just a few years ago."

Margutti, Jacobson-Galán and their Northwestern co-authors are members of the Young Supernova Experiment, which uses the Pan-STARRS telescope to catch supernovae right after they explode.

Read more at Science Daily

Microbes produce oxygen in the dark

It is common knowledge that there would be no oxygen on Earth were it not for sunlight; the key component in photosynthesis. Now researchers have made the surprising discovery that oxygen is also produced without sunlight, possibly deep below the ocean surface. There is more going on in the deep, dark ocean waters than you may think: Uncountable numbers of invisible microorganisms go about their daily lives in the water columns, and now researchers have discovered that some of them produce oxygen in an unexpected way.

The study is led by Beate Kraft and Donald E. Canfield from University of Southern Denmark and published in the journal Science. Contributing authors are Nico Jehmlich, Morten Larsen, Laura Bristow, Martin Könneke and Bo Thamdrup. Beate Kraft is an assistant professor at Department of Biology. Her focus is on microbial physiology and biochemistry, and her research is supported by a Villum Young Investigator Grant. Don E. Canfield is Professor of Ecology at the Department of Biology and Danish Institute for Andvance Study chair of Biology.

Oxygen is vital for life on Earth, and is mainly produced by plants, algae and cyanobacteria via photosynthesis. A few microbes are known to make oxygen without sunlight, but so far they have only been discovered in very limited quantities and in very specific habitats.

Enter the ocean living microbe Nitrosopumilus maritimus and its cousins, called ammonia oxidizing archaea.

Ghost organisms hanging out in the dark

"These guys are really abundant in the oceans, where they play an important role in the nitrogen cycle. For this they need oxygen, so it has been a long standing puzzle why they are also very abundant in waters where there is no oxygen," says biologist Beate Kraft, adding:

-"We thought; They just hang out there with no function; they must be some kind of ghost cells."

But there was something puzzling to this;

"These microbes are socommon, that every 5th cell in a bucket of sea water is one of them," adds Don Canfield, co-author of the paper.

So the researchers became curious; could they have a function in the oxygen depleted water after all?

They make their own oxygen

Beate Kraft decided to test them in the lab;

"We wanted to see what would happen if they ran out of oxygen -- like they do when they move from the oxygen rich waters to oxygen depleted waters. Would they survive?"

"We saw how they used up all the oxygen in the water, and then to our surprise, within minutes, oxygen levels started increasing again. That was very exciting!," Don Canfield recalls.

Enough for me and my friends

Nitrosopumilus maritimus turned out to be able to make oxygen in a dark environment. Not much -- not at all so much that it would influence oxygen levels on Earth, but enough to keep itself going.

"If they produce a little more oxygen than they need themselves, it will quickly be taken by other organisms in their neighborhood, so this oxygen would never leave the ocean," Beate Kraft explains.

But what effect do they have on the environment they live in, these extremely abundant oxygen-producing microbes?

New ocean expedition

Researchers already knew that the ammonia oxidizing archaea are microorganisms, that keep the global nitrogen cycle going, but they were not aware of the full extent of their capabilities.

In the newly discovered pathway, Nitrosopumilus maritimus couples the oxygen production to the production of gasous nitrogen. By doing so they remove bioavailable nitrogen from the environment.

"If this lifestyle is widespread in the oceans, it certainly forces us to rethink our current understanding of the marine nitrogen cycle," adds Beate Kraft.

"My next step is to investigate the phenomenon we saw in our lab cultures in oxygen depleted waters in various ocean spots around the world," she adds.

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School closures led to more sleep and better quality of life for adolescents

The school closures in spring 2020 had a negative effect on the health and well-being of many young people. But homeschooling also had a positive flipside: Thanks to sleeping longer in the morning, many teenagers reported improved health and health-related quality of life. The study authors from the University of Zurich therefore believe school days should begin later in the morning.

The first wave of the Covid-19 pandemic led to the closure of all schools nationwide from 13 March to 6 June 2020. According to multiple studies, symptoms of depression and anxiety among young people increased during this time, while satisfaction and quality of life decreased. The schoolchildren were also less physically active and spent more time sitting in front of screens.

Now, a study by the University of Zurich (UZH) has shown that the homeschooling phase also had a positive effect on the health and well-being of many teenagers. "The students got about 75 minutes more sleep per day during the lockdown. At the same time, their health-related quality of life improved significantly and their consumption of alcohol and caffeine went down," says the study's co-leader Oskar Jenni, UZH professor of developmental pediatrics. Because they no longer had to travel to school, they were able to get up later.

More sleep on school days improves young people's health-related quality of life

The researchers conducted an online survey with 3,664 high school students in the Canton of Zurich during the lockdown, asking about their sleep patterns and quality of life. They then compared the answers with a survey from 2017 with 5,308 young participants. The results showed that during the three months in which the schools were closed, the adolescents got up around 90 minutes later on school days, but went to bed only 15 minutes later on average -- meaning their total amount of sleep increased by about 75 minutes a day. On weekends, there was little difference in the sleep times of the two groups.

The students in the lockdown group rated their health-related quality of life higher, and the amount of alcohol and caffeine they reported consuming was less than the pre-pandemic group. "Although the lockdown clearly led to worse health and well-being for many young people, our findings reveal an upside of the school closures which has received little attention until now," says Jenni.

Unique opportunity to investigate the effect of later school starting times

Sleep deficits in adolescents can lead to general tiredness, anxiety and physical ailments. These in turn have a detrimental effect on cognitive functions such as concentration, memory and attention, making it significantly harder to function in everyday life. The early start of the school day in Switzerland conflicts with the natural, biologically determined sleeping habits of teenagers. Because they have to get up early for school, many young people therefore suffer from chronic lack of sleep. The topic has recently made its way onto the political agenda in several cantons across the country.

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How exercise interventions could help people with asthma

Interventions aimed at promoting physical activity in people with asthma could improve their symptoms and quality of life -- according to new research from the University of East Anglia.

Researchers looked at whether interventions such as aerobic and strength or resistance training, had helped participants with asthma.

Although they found that these interventions worked, patients with asthma may have had difficulty undertaking them because of their difficulty travelling to fitness groups or because the interventions were not suitable for people with additional health conditions.

But the team say that digital interventions -- such as video appointments, smartwatches and mobile apps -- could remove some of these barriers and enable patients to carry out home-based programmes in future.

Prof Andrew Wilson, from UEA's Norwich Medical School, said: "Being physically active is widely recommended for people with asthma. Doing more than 150 minutes a week of moderate to vigorous physical activity has extensive benefits including improved lung function and asthma control.

"But research has shown that people living with asthma engage in less physical activity and are more sedentary than people without asthma.

"We wanted to find out whether interventions -- such as being asked to perform aerobic exercise a few times a week in group sessions, together with 'goal setting' -- are effective in helping people with asthma be more active."

The team studied interventions that were designed to promote physical activity in adults with asthma. They looked at 25 separate studies from around the world involving 1,849 participants with asthma, to see whether their symptoms and quality of life were changed thanks to the interventions.

Postgraduate researcher Leanne Tyson, also from UEA's Norwich Medical School said: "We found that interventions that promote physical activity had significant benefits in terms of increasing physical activity, decreasing time spent sedentary, improving quality of life, and decreasing asthma symptoms.

"This is really important because helping patients make significant behaviour changes could really improve their outcomes in the long term.

"Our review also highlights the potential use of digital interventions, which were notably absent.

"This is important now more than ever as patients have not been able to attend face-to-face support during the Covid-19 pandemic, and services will likely become overwhelmed. Therefore, alternative interventions and methods of delivery need to be considered."

Read more at Science Daily

Sending life to the stars

No longer solely in the realm of science fiction, the possibility of interstellar travel has appeared, tantalizingly, on the horizon. Although we may not see it in our lifetimes -- at least not some real version of the fictional warp-speeding, hyperdriving, space-folding sort -- we are having early conversations of how life could escape the tether of our solar system, using technology that is within reach.

For UC Santa Barbara professors Philip Lubin and Joel Rothman, it's a great time to be alive. Born of a generation that saw breathtaking advances in space exploration, they carry the unbridled optimism and creative spark of the early Space Age, when humans first found they could leave the Earth.

"The Apollo moon voyages were among the most momentous events in my life and contemplating them still blows my mind," said Rothman, a distinguished professor in the Department of Molecular, Cellular and Developmental Biology, and a self-admitted "space geek."

A mere 50 years have passed since that pivotal era, but humanity's knowledge of space and the technology to explore it have improved immensely, enough for Rothman to join experimental cosmologist Lubin in considering what it would take for living beings to embark on a journey across the vast distance separating us from our nearest neighbor in the galaxy. The result of their collaboration was published in the journal Acta Astronautica.

"I think it's our destiny to keep exploring," Rothman said. "Look at the history of the human species. We explore at smaller and smaller levels down to subatomic levels and we also explore at increasingly larger scales. Such drive toward ceaseless exploration lies at the core of who we are as a species."

Thinking Big, Starting Small

The biggest challenge to human-scale interstellar travel is the enormous distance between Earth and the nearest stars. The Voyager missions have proven that we can send objects across the 12 billion miles it takes to exit the bubble surrounding our solar system, the heliosphere. But the car-sized probes, traveling at speeds of more than 35,000 miles per hour, took 40 years to reach there and their distance from Earth is only a tiny fraction of that to the next star. If they were headed to the closest star, it would take them over 80,000 years to reach it.

That challenge is a major focus of Lubin's work, in which he reimagines the technology it would take to reach the next solar system in human terms. Traditional onboard chemical propulsion (a.k.a. rocket fuel) is out; it can't provide enough energy to move the craft fast enough, and the weight of it and current systems needed to propel it are not viable for the relativistic speeds the craft needs to achieve. New propulsion technologies are required -- and this is where the UCSB directed energy research program of using light as the "propellant" comes in.

"This has never been done before, to push macroscopic objects at speeds approaching the speed of light," said Lubin, a professor in the Department of Physics. Mass is such a huge barrier, in fact, that it rules out any human missions for the foreseeable future.

As a result, his team turned to robots and photonics. Small probes with onboard instrumentation that sense, collect and transmit data back to Earth will be propelled up to 20-30% of the speed of light by light itself using a laser array stationed on Earth, or possibly the moon. "We don't leave home with it," as Lubin explained, meaning the primary propulsion system stays "at home" while spacecraft are "shot out" at relativistic speeds. The main propulsion laser is turned on for a short period of time and then the next probe is readied to be launched.

"It would probably look like a semiconductor wafer with an edge to protect it from the radiation and dust bombardment as it goes through the interstellar medium," Lubin said. "It would probably be the size of your hand to start with." As the program evolves the spacecraft become larger with enhanced capability. The core technology can also be used in a modified mode to propel much larger spacecraft within our solar system at slower speeds, potentially enabling human missions to Mars in as little as one month, stopping included. This is another way of spreading life, but in our solar system.

At these relativistic speeds -- roughly 100 million miles per hour -- the wafercraft would reach the next solar system, Proxima Centauri, in roughly 20 years. Getting to that level of technology will require continuous innovation and improvement of both the space wafer, as well the photonics, where Lubin sees "exponential growth" in the field. The basic project to develop a roadmap to achieve relativistic flight via directed energy propulsion is supported by NASA and private foundations such as the Starlight program and by the Breakthrough Initiatives as the Starshot program.

"When I learned that the mass of these craft could reach gram levels or larger, it became clear that they could accomodate living animals," said Rothman, who realized that the creatures he'd been studying for decades, called C. elegans, could be the first Earthlings to travel between the stars. These intensively studied roundworms may be small and plain, but they are experimentally accomplished creatures, Rothman said.

"Research on this little animal has led to Nobel prizes to six researchers thus far," he noted.

C. elegans are already veterans of space travel, as the subject of experiments conducted on the International Space Station and aboard the space shuttle, even surviving the tragic disintegration of the Columbia shuttle. Among their special powers, which they share with other potential interstellar travelers that Rothman studies, tardigrades (or, more affectionately, water bears) can be placed in suspended animation in which virtually all metabolic function is arrested. Thousands of these tiny creatures could be placed on a wafer, put in suspended animation, and flown in that state until reaching the desired destination. They could then be wakened in their tiny StarChip and precisely monitored for any detectable effects of interstellar travel on their biology, with the observations relayed to Earth by photonic communication.

"We can ask how well they remember trained behavior when they're flying away from their eathly origin at near the speed of light, and examine their metabolism, physiology, neurological function, reproduction and aging," Rothman added. "Most experiments that can be conducted on these animals in a lab can be performed onboard the StarChips as they whiz through the cosmos." The effects of such long odysseys on animal biology could allow the scientists to extrapolate to potential effects on humans.

"We could start thinking about the design of interstellar transporters, whatever they may be, in a way that could ameliorate the issues that are detected in these diminutive animals," Rothman said.

Of course, being able to send humans to interstellar space is great for movies, but in reality is still a far away dream. By the time we get to that point we may have created more suitable life forms or hybrid human-machines that are more resilient.

"This is a generational program," Lubin said. Scientists of coming generations ideally will contribute to our knowledge of interstellar space and its challenges, and enhance the design of the craft as technology improves. With the primary propulsion system being light, the underlying technology is on an exponential growth curve, much like electronics with a "Moore's Law" like expanding capability.

Planetary Protection and Extraterrestrial Propagation

We're bound to our solar system for the forseeable future; humans are fragile and delicate away from our home planet. But that hasn't stopped Lubin, Rothman, their research teams and their diverse collaborators, which include a radiation specialist and a science-trained theologian, to contemplate both the physiological and ethical aspects of sending life to space -- and perhaps even propagating life in space.

"There are the ethics," Lubin explained, "of planetary protection," in which serious thought is given to the possibility of contamination, either from our planet to others or vice versa. "I think if you started talking about directed propagation of life, which is sometimes called panspermia -- this idea that life came from elsewhere and ended up on the earth by comets and other debris, or even intentionally from another civilization -- the idea that we would purposefully send out life does bring up big questions."

So far, the authors contend, there is no risk of forward contamination, as the probes nearing any other planet would burn up in their atmosphere or be obliterated in the collision with the surface. Because the wafercraft are on a one-way trip, there's no risk that any extraterrestrial microbes will return to Earth.

While still somewhat on the fringe, the theory of panspermia seems to be getting some serious, if limited, attention, given how easy it is to propagate life when conditions are right and the discovery of several exoplanets and other celestial bodies that may have been, or could be, supportive of life as we know it.

"Some people have mused and published on ideas such as 'is the universe a lab experiment from some advanced civilization,'" Lubin said. "So people are certainly willing to think about advanced civilizations. Questions are good but answers are better. Right now we simply ponder these questions without the answers yet."

Another issue currently being contemplated in the wider space exploration community: What are the ethics of sending humans to Mars and other distant places knowing they may never come home? What about sending out small micro-organisms or human DNA? These existential inquiries are as old as the first human migrations and seafaring voyages, the answers to which will likely come the moment we're ready to take these journeys.

Read more at Science Daily

Modern humans developed a more effective protection against oxidative stress

Very few proteins in the body have a change that makes them unique compared to the corresponding proteins in Neanderthals and apes. Researchers at the Max Planck Institute for Evolutionary Anthropology in Germany and Karolinska Institutet in Sweden have now studied one such protein, glutathione reductase, which protects against oxidative stress. They show that the risk for inflammatory bowel disease and vascular disease is increased several times in people carrying the Neanderthal variant.

What makes modern humans unique is a question that has eluded researchers for a long time. One way to approach this question is to study the proteins, or building blocks, in the body that have changes that are carried by almost all living people today and occurred after we separated from the ancestors we shared with Neanderthals about 500,000 years ago. There are around 100 proteins that have such a unique change. One of these proteins is glutathione reductase which is part of the body's defense against oxidative stress.

The study, which is published in the journal Science Advances, examines the change in glutathione reductase in detail and was led by Hugo Zeberg at Karolinska Institutet and the Max Planck Institute for Evolutionary Anthropologyand Svante Pääbo at the Max Planck Institute. They show that the Neanderthal protein created more reactive oxygen radicals which are the cause of oxidative stress. It is the third protein change unique to present-day humans that has been studied so far.

The study also shows that the Neanderthal protein has passed over to present-day humans in low frequency when our ancestors mixed with them about 60,000 years ago. Today, it occurs mainly on the Indian subcontinent at an estimated frequency of 1 to 2 per cent of the population. The researchers found that people who carry the Neanderthal protein have a higher risk of developing vascular disease and inflammatory bowel disease, both diseases that are linked to oxidative stress.

"The risk increases we see are large; several times increased risk of inflammatory bowel disease and vascular disease," says Hugo Zeberg.

The researchers can only speculate about why this particular change came to be one of the unique changes that almost all modern humans carry.

"Stopping oxidative stress is a bit like preventing something from rusting. Perhaps the fact that we are living longer has driven these changes," says Svante Pääbo.

Read more at Science Daily

Air pollution from wildfires, rising heat affected 68% of US West in one day

Large wildfires and severe heat events are happening more often at the same time, worsening air pollution across the western United States, a study led by Washington State University researchers has found. In 2020, more than 68% of the western U.S. -- representing about 43 million people -- were affected in one day by the resulting harmful-levels of air pollution, the highest number in 20 years.

The study, published in Science Advances, found that such widespread air pollution events are not only increasing in frequency but also persisting longer and affecting a larger geographic extent across the region. They have become so bad that they have reversed many gains of the Clean Air Act. The conditions that create these episodes are also expected to continue to increase, along with their threats to human health.

"We have seen an increasing trend in the past 20 years of days when high-levels of both particulate matter and ozone are occurring simultaneously," said lead author Dmitri Kalashnikov, a WSU doctoral student. "This is tied to two things: more wildfires and increases in the types of weather patterns that cause both wildfires and hot weather."

When wildfires and extreme heat occur at the same time, they magnify air pollution: wildfire smoke increases fine particulate matter in the air and the heat combines the smoke and other pollutants to create more ground-level ozone. While in the stratosphere ozone is protective, ozone that forms at the ground level has long been recognized as harmful to human health. It's a major component of smog, and reducing it was a major goal of clean air policies in the twentieth century. Simultaneous exposure of millions of people to high levels of both pollutants, ground-level ozone and particulate matter, poses a substantial public health burden.

Weather patterns called high-pressure ridging, more commonly known as heat domes, occur when an area of high-pressure air lingers over a region trapping warm stagnant air and its pollutants on the ground. These conditions typically lead to higher levels of harmful ground-level ozone during summer months. Particulate matter affecting air quality used to be more common in the winter in the western United States, but wildfires have flipped that dynamic, bringing the dangers of both particulate matter and ground-level ozone together at the same time in the summer.

For this study, the researchers tracked air quality by using all available monitoring station data from 2001-2020 from across the western states as well as parts of Canada. They combined this data with wildfire information derived from NASA satellites along with ERA5 weather data produced by the European Center for Medium-Range Weather Forecasts.

The co-occurring events were defined as days that registered in both the top 10% in particulate matter levels and top 10% in ozone. The researchers found that annual population exposure to these extreme combined episodes is increasing by approximately 25 millionperson-days a year- a figure that counts the number of people affected as well as the number of days they were impacted by the air pollution.

"From every indication we have, the hotter, drier conditions projected for this region are likely to increase wildfire activity and contribute to more widespread, severe heat, which means we can expect to see these conditions happen more often in the future," said co-author Deepti Singh, a WSU assistant professor. "Preparing for these events is really important. We need to think about who is exposed, what capacity there is to minimize that exposure, and how we can protect the most vulnerable people."

These events could potentially be mitigated by taking measures to slow the temperature rise caused by climate change as well as better managing wildfires, such as through prescribed burns. Aside from those efforts, Kalashnikov and Singh suggested treating these air pollution events like a severe snowstorm or heatwave by making sure people have shelters with air quality filters where they can go to get out of polluted air. They also recommended adopting policies that minimize workplace exposure for people who typically work outside.

The size of the simultaneous air pollution events will make it difficult for many people to avoid their impacts, Singh said.

"If there's such a large region that's being affected by this air pollution, it really limits where people can go to escape those conditions," she said. "You could travel a hundred miles and still not find air quality that is any better."

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Innovative approach brings cell-reprograming therapy for heart failure closer to reality

Not too long ago the idea of taking, for instance a skin cell and transforming it into a muscle cell was unthinkable. About 10 years ago, however, revolutionary research showed that it is indeed possible to reprogram differentiated adult cells into other types fully capable of conducting new functions.

Cell reprogramming is a main interest of the lab of Dr. Todd Rosengart, chair and professor of the Michael E. DeBakey Department of Surgery at Baylor College of Medicine, whose research focuses on finding innovative therapeutic approaches for heart failure.

"Heart failure remains the leading cause of death from heart disease," said Rosengart, DeBakey-Bard Chair in Surgery and professor of molecular and cellular biology at Baylor. "Nearly 5 million Americans can be expected to develop advanced congestive heart failure, and heart transplant or mechanical circulatory support implantation currently are the only options for patients with end-stage heart disease. However, these options are limited. We need to improve how to treat this devastating condition."

After a heart attack, the parts of the heart muscle that die do not regenerate into new heart tissue; instead, they are replaced by a scar that does not help the heart to beat. "The idea behind cell reprograming is to coach the heart to heal itself by inducing the scar tissue, which is made mostly of fibroblasts, to change into functional heart muscle," said Rosengart, professor of heart and vascular disease at the Texas Heart Institute.

Researchers have succeeded at reprograming fibroblasts from small animals to become heart muscle, with dramatic improvements in heart function. The challenge has been to apply this technology to human cells -- human fibroblasts are more resistant to reprograming. In this study, Rosengart and his colleagues explored a novel strategy to enhance the reprogramming efficiency of human fibroblasts.

"While human fibroblasts resist being reprogramed, endothelial cells, those that line the blood vessels, are known to be more flexible -- they have the capacity to naturally transdifferentiate or change into other cells," said co-first author Dr. Megumi Mathison, associate professor of surgery at Baylor. "This gave us the idea of using this endothelial cell plasticity to improve the reprograming efficiency."

The researchers' idea was to first induce fibroblasts to transition into an endothelial cell-like state and then treat these cells with their reprograming cocktail that directs them to change into cardiomyocytes. The expectation was that transitioning into endothelial cell-like cells, a cell type more open to reprogramming than fibroblasts, would facilitate the desired change into heart muscle.

"We were delighted to see that our approach significantly enhanced reprogramming efficiency both in human and rat fibroblasts," Mathison said. "Previously, inducing cardiomyocytes from fibroblasts directly was only 3% efficient. With our new approach, the efficiency increased 5 times. It took about two to three weeks for the fibroblasts to transition into cardiomyocytes in the lab. It was exciting to see the reprogrammed cells contracting in synchrony with surrounding cardiomyocytes."

The researchers' experimental results with the rat model show that their new strategy can revert large scar tissue into working muscle, supporting continuing their investigations to bring this procedure to the clinic.

"Although more research is needed, we anticipate that this novel approach can become part of the next generation of biological therapies," Rosengart said. "In a future scenario, patients with congestive heart failure would come to the catheterization laboratory, commonly referred to as the cath lab, in a hospital. The cath lab has diagnostic imaging equipment that helps surgeons visualize the chambers of the heart and surrounding blood vessels as they conduct procedures. Assisted by this equipment, the surgeon would inject the factors that promote the transition from fibroblasts to endothelial cells and then to cardiomyocytes directly into the heart. Follow ups would monitor the progress of the procedure."

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Earth isn’t 'super' because the sun had rings before planets

Before the solar system had planets, the sun had rings -- bands of dust and gas similar to Saturn's rings -- that likely played a role in Earth's formation, according to a new study.

"In the solar system, something happened to prevent the Earth from growing to become a much larger type of terrestrial planet called a super-Earth," said Rice University astrophysicist André Izidoro, referring to the massive rocky planets seen around at least 30% of sun-like stars in our galaxy.

Izidoro and colleagues used a supercomputer to simulate the solar system's formation hundreds of times. Their model, which is described in a study published online in Nature Astronomy, produced rings like those seen around many distant, young stars. It also faithfully reproduced several features of the solar system missed by many previous models, including:
 

• An asteroid belt between Mars and Jupiter containing objects from both the inner and outer solar system.
• The locations and stable, almost circular orbits of Earth, Mars, Venus and Mercury.
• The masses of the inner planets, including Mars, which many solar system models overestimate.
• The dichotomy between the chemical makeup of objects in the inner and outer solar system.
• A Kuiper belt region of comets, asteroids and small bodies beyond the orbit of Neptune.

The study by astronomers, astrophysicists and planetary scientists from Rice, the University of Bordeaux, Southwest Research Institute in Boulder, Colorado, and the Max Planck Institute for Astronomy in Heidelberg, Germany, draws on the latest astronomical research on infant star systems.

Their model assumes three bands of high pressure arose within the young sun's disk of gas and dust. Such "pressure bumps" have been observed in ringed stellar disks around distant stars, and the study explains how pressure bumps and rings could account for the solar system's architecture, said lead author Izidoro, a Rice postdoctoral researchers who received his Ph.D. training at Sao Paulo State University in Brazil.

"If super-Earths are super-common, why don't we have one in the solar system?" Izidoro said. "We propose that pressure bumps produced disconnected reservoirs of disk material in the inner and outer solar system and regulated how much material was available to grow planets in the inner solar system."

Pressure bumps

For decades, scientists believed gas and dust in protoplanetary disks gradually became less dense, dropping smoothly as a function of distance from the star. But computer simulations show planets are unlikely to form in smooth-disk scenarios.

"In a smooth disk, all solid particles -- dust grains or boulders -- should be drawn inward very quickly and lost in the star," said astronomer and study co-author Andrea Isella, an associate professor of physics and astronomy at Rice. "One needs something to stop them in order to give them time to grow into planets."

When particles move faster than the gas around them, they "feel a headwind and drift very quickly toward the star," Izidoro explained. At pressure bumps, gas pressure increases, gas molecules move faster and solid particles stop feeling the headwind. "That's what allows dust particles to accumulate at pressure bumps," he said.

Isella said astronomers have observed pressure bumps and protoplanetary disk rings with the Atacama Large Millimeter/submillimeter Array, or ALMA, an enormous 66-dish radio telescope that came online in Chile in 2013.

"ALMA is capable of taking very sharp images of young planetary systems that are still forming, and we have discovered that a lot of the protoplanetary disks in these systems are characterized by rings," Isella said. "The effect of the pressure bump is that it collects dust particles, and that's why we see rings. These rings are regions where you have more dust particles than in the gaps between rings."

Ring formation

The model by Izidoro and colleagues assumed pressure bumps formed in the early solar system at three places where sunward-falling particles would have released large amounts of vaporized gas.

"It's just a function of distance from the star, because temperature is going up as you get closer to the star," said geochemist and study co-author Rajdeep Dasgupta, the Maurice Ewing Professor of Earth Systems Science at Rice. "The point where the temperature is high enough for ice to be vaporized, for example, is a sublimation line we call the snow line."

In the Rice simulations, pressure bumps at the sublimation lines of silicate, water and carbon monoxide produced three distinct rings. At the silicate line, the basic ingredient of sand and glass, silicon dioxide, became vapor. This produced the sun's nearest ring, where Mercury, Venus, Earth and Mars would later form. The middle ring appeared at the snow line and the farthest ring at the carbon monoxide line.

Rings birth planetesimals and planets

Protoplanetary disks cool with age, so sublimation lines would have migrated toward the sun. The study showed this process could allow dust to accumulate into asteroid-sized objects called planetesimals, which could then come together to form planets. Izidoro said previous studies assumed planetesimals could form if dust were sufficiently concentrated, but no model offered a convincing theoretical explanation of how dust might accumulate.

"Our model shows pressure bumps can concentrate dust, and moving pressure bumps can act as planetesimal factories," Izidoro said. "We simulate planet formation starting with grains of dust and covering many different stages, from small millimeter-sized grains to planetesimals and then planets."

Accounting for cosmochemical signatures, Mars' mass and the asteroid belt

Many previous solar system simulations produced versions of Mars as much as 10 times more massive than Earth. The model correctly predicts Mars having about 10% of Earth's mass because "Mars was born in a low-mass region of the disk," Izidoro said.

Dasgupta said the model also provides a compelling explanation for two of the solar system's cosmochemical mysteries: the marked difference between the chemical compositions of inner- and outer-solar system objects, and the presence of each of those objects in the asteroid belt between Mars and Jupiter.

Izidoro's simulations showed the middle ring could account for the chemical dichotomy by preventing outer-system material from entering the inner system. The simulations also produced the asteroid belt in its correct location, and showed it was fed objects from both the inner and outer regions.

"The most common type of meteorites we get from the asteroid belt are isotopically similar to Mars," Dasgupta said. "Andre explains why Mars and these ordinary meteorites should have a similar composition. He's provided a nuanced answer to this question."

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Ancient Maya lessons on surviving drought

A new study casts doubt on drought as the driver of ancient Mayan civilization collapse.

There is no dispute that a series of droughts occurred in the Yucatan Peninsula of southeastern Mexico and northern Central America at the end of the ninth century, when Maya cities mysteriously began to be depopulated. Believing the Maya were mostly dependent on drought-sensitive corn, beans, and squash, some scholars assume the droughts resulted in starvation.

However, a new analysis by UC Riverside archaeologist Scott Fedick and plant physiologist Louis Santiago shows the Maya had nearly 500 edible plants available to them, many of which are highly drought resistant. The results of this analysis have now been published in the Proceedings of the National Academy of Sciences.

"Even in the most extreme drought situation -- and we have no clear evidence the most extreme situation ever occurred -- 59 species of edible plants would still have persisted," Santiago said.

Some of the toughest plants the Maya would have turned to include cassava with its edible tubers, and hearts of palm. Another is chaya, a shrub domesticated by the Maya and eaten today by their descendants. Its leaves are high in protein, iron, potassium, and calcium.

"Chaya and cassava together would have provided a huge amount of carbohydrates and protein," Santiago said.

Unable to find a master list of indigenous Maya food plants, Fedick recently compiled and published one that draws on decades of Maya plant knowledge. Faced with much speculation about drought as the cause of Maya social disruptions, he and Santiago decided to examine all 497 plants on the list for drought tolerance.

"When botanists study drought resistance, they're usually talking about a specific plant, or a particular ecosystem," Fedick said. "One of the reasons this project was so challenging is because we examined the dietary flora of an entire civilization -- annuals, perennials, herbs, trees, domesticates, and wild species. It was a unique endeavor."

Though the researchers do not have a clear answer about why ancient Maya society unraveled, they suspect social and economic upheaval played a role.

"One thing we do know is the overly simplistic explanation of drought leading to agricultural collapse is probably not true," Fedick said.

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New research shows gene exchange between viruses and hosts drives evolution

The first comprehensive analysis of viral horizontal gene transfer (HGT) illustrates the extent to which viruses pick up genes from their hosts to hone their infection process, while at the same time hosts also co-opt useful viral genes.

HGT is the movement of genetic material between disparate groups of organisms, rather than by the "vertical" transmission of DNA from parent to offspring. Previous studies have looked at HGT between bacteria and their viruses and have shown that it plays a major role in the movement of genes between bacterial species. However the new study, published in Nature Microbiology, looks at interactions between viruses and eukaryotes, which include animals, plants, fungi, protists and most algae.

"We knew from individual examples that viral genes have played a role in the evolution of eukaryotes. Even humans have viral genes, which are important for our development and brain function," said the study's lead author, Dr. Nicholas Irwin, a Junior Research Fellow at Merton College, University of Oxford, and former PhD student at the University of British Columbia (UBC). "We wanted to understand more broadly how HGT has affected viruses and eukaryotes from across the tree of life."

To tackle this problem, the authors examined viral-eukaryotic gene transfer in the genomes of hundreds of eukaryotic species and thousands of viruses. They identified many genes that had been transferred and found that HGT from eukaryotes to viruses was twice as frequent as the reverse direction.

"We were interested to find that certain groups of viruses, especially those that infect single-celled eukaryotes, acquire a lot of genes from their hosts," said the study's senior author, Dr. Patrick Keeling, a professor in the Department of Botany at UBC. "By studying the function of these genes we were able to make predictions about how these viruses affect their hosts during infection."

In contrast to viruses, eukaryotic organisms retained fewer viral genes, although the ones that were kept appear to have had a major impact on host biology over evolutionary time.

"Many of these viral-derived genes appear to have repeatedly affected the structure and form of different organisms, from the cell walls of algae to the tissues of animals," said Dr. Irwin. "This suggests that host-virus interactions may have played an important role in driving the diversity of life we see today."

"These transfers not only have evolutionary consequences for both virus and host, but could have important health implications," Dr. Keeling said.

HGT allows genes to jump between species including viruses and their hosts. If the gene does something useful, it can sweep through the population and become a feature of that species. This can lead to a rapid emergence of new abilities, as opposed to the more incremental changes that result from smaller mutations.

Although viruses such as Zika and coronaviruses do not appear to participate in these gene transfers, they often manipulate similar genes in their hosts through complex mechanisms. Future research into these transferred genes may therefore provide a novel approach for understanding the infection processes of these and other viruses which could be important for drug discovery.

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New target may help protect bones as we age

Drugs we take like prednisone can weaken our bones and so can aging, and scientists working to prevent both have some of the first evidence that the best target may not be the logical one.

They are finding that in aging bone, the mineralocorticoid receptor, better known for its role in blood pressure regulation, is a key factor in bone health, says Dr. Meghan E. McGee-Lawrence, biomedical engineer in the Department of Cellular Biology and Anatomy at the Medical College of Georgia.

And drugs that block the receptor, like the hypertension medications spironolactone and eplerenone, may help protect bone cells, says McGee-Lawrence, corresponding author of the study in the Journal of Bone and Mineral Research.

Drugs like prednisone are glucocorticoids, which are better known for their roles in reducing inflammation and suppressing the immune response, which is why they work so well for problems like irritable bowel syndrome and arthritis. But, like aging, they can also disrupt the healthy, ongoing dynamic of bone being made and being destroyed.

Our natural glucocorticoid levels increase with age, and bone, at least when we are young, has more glucocorticoid receptors than mineralocorticoid receptors. Glucocorticoids can actually coax stem cells to make bone-forming osteoblasts, but it also causes those osteoblasts to store more fat, and too much fat in the bone, like anywhere on our body, is probably not good and typically correlates with bone loss, McGee-Lawrence says.

So reducing the impact of glucocorticoid receptors seemed like a logical way to protect bone.

The MCG scientists had already been surprised to find that the loss of functioning glucocorticoid receptors did not protect against bone loss in younger mice on calorie-restricted diets. In fact, there was increased fat accumulation in the bone marrow and worsened osteoporosis.

This time they were looking at the impact of endogenous glucocorticoids in an aging model, and found again that when the glucocorticoid receptor was blocked, older mice also experienced more fat accumulation in the bone marrow and worsening bone disease.

They also found that the mice had a smaller muscle mass, chose to move around less than mice typically do and had higher blood pressure.

Another surprise was that when they used drugs to inhibit the mineralocorticoid receptor, many of the problems were reversed.

"The only way we have found to get rid of that lipid storage by osteoblasts was to inhibit the mineralocorticoid receptor with drugs," she says, and fortunately because of the receptors' clear role in blood pressure there are already drugs that do that.

"I think what it means is if we want to understand what these stress hormones, these endogenous glucocorticoids, are doing we cannot just think about signaling through one receptor," McGee-Lawrence says. For older bone, she thinks mineralocorticoid receptors may be a better target.

"We thought that knocking out the glucocorticoid receptor would make things better, but it made them worse," McGee-Lawrence says. "We think the mineralocorticoid receptor may explain a lot of what is going wrong in aging bone."

Both receptors are members of the steroid receptor family and mineralocorticoid receptors are thought to have equal affinity for mineralocorticoids and glucocorticoids. It may be the signaling paths are different in young and older individuals, she notes.

McGee-Lawrence and her colleagues already have some evidence that bone's expression of mineralocorticoid receptors goes up, potentially significantly, as you age. They have early mixed results on whether glucocorticoid receptors go down with age and are exploring more about what happens with both receptor levels as well as learning more about the role of mineralocorticoid receptors in bone, particularly aging bone.

"We want to know what would cause bone cells to change which receptors they are expressing and how they are responding to these," she says. "But there are a lot of things that happen with aging. We know inflammation changes with aging, so there are a lot of different cues that could cause these things to change."

The whole body impact they saw from their manipulation of receptors, like a higher blood pressure from deleting the glucocorticoid receptor, also is evidence of bone's importance as an endocrine organ, she says.

"By changing glucocorticoid signaling in the bone, not only are we seeing changes in the bone, but we are seeing changes in the fat, muscle, adrenal glands, in physical activity," she says which means something from the bone is communicating with all these other body systems, an emerging role of research in her field.

In fact, the increased fat presence in the bone marrow found in osteoporosis has resulted in it also being considered a metabolic disease of the bone, much as obesity, particularly excess weight around the middle, is considered a metabolic disease. Increased fat in the bone marrow is associated with disuse, like following a spinal cord injury, a high-fat diet, taking glucocorticoids, like steroids, and aging.

While the fat is a ready energy source for bone cells, too much can hinder bone cell formation. The scientists don't yet know whether the cells are no longer using fat well or they are pulling more in, or both; they do know fat accumulating in the bone cells coincides with less bone being made, she reiterates.

"We are trying to figure out exactly why these things are going wrong so that we can pick the right avenue to pursue for a treatment strategy," she says.

There is a lot of evidence in people that the synthetic glucocorticoids we take via pill or injection, can impact bone, creating an unhealthy imbalance between the amount of bone made and the amount broken down.

A focus of the research at MCG has been examining the bone impact from our endogenous glucocorticoids, the ones we make, a less-explored area. For years, McGee-Lawrence and her colleagues have been studying bone-forming osteoblasts which, like most cells, don't function optimally as we age.

But it may be that even synthetic glucocorticoids also work through these alternative receptors to damage the bone, which means trying to prevent their damage may also mean a different target, she says, noting again that the pathway may change as the person ages.

Interestingly some other tissues that are known to have a lot of mineralocorticoid receptors inactivate glucocorticoids, which bone cannot do, but perhaps it compensates by not having a lot of mineralocorticoid receptors, at least in youth, she says.

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Bringing the sun into the lab

Why the Sun's corona reaches temperatures of several million degrees Celsius is one of the great mysteries of solar physics. A "hot" trail to explain this effect leads to a region of the solar atmosphere just below the corona, where sound waves and certain plasma waves travel at the same speed. In an experiment using the molten alkali metal rubidium and pulsed high magnetic fields, a team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a German national lab, has developed a laboratory model and for the first time experimentally confirmed the theoretically predicted behavior of these plasma waves -- so-called Alfvén waves -- as the researchers report in the journal Physical Review Letters.

At 15 million degrees Celsius, the center of our Sun is unimaginably hot. At its surface, it emits its light at a comparatively moderate 6000 degrees Celsius. "It is all the more astonishing that temperatures of several million degrees suddenly prevail again in the overlying Sun's corona," says Dr. Frank Stefani. His team conducts research at the HZDR Institute of Fluid Dynamics on the physics of celestial bodies -- including our central star. For Stefani, the phenomenon of corona heating remains one of the great mysteries of solar physics, one that keeps running through his mind in the form of a very simple question: "Why is the pot warmer than the stove?"

That magnetic fields play a dominant role in heating the Sun's corona is now widely accepted in solar physics. However, it remains controversial whether this effect is mainly due to a sudden change in magnetic field structures in the solar plasma or to the dampening of different types of waves. The new work of the Dresden team focuses on the so-called Alfvén waves that occur below the corona in the hot plasma of the solar atmosphere, which is permeated by magnetic fields. The magnetic fields acting on the ionized particles of the plasma resemble a guitar string, whose playing triggers a wave motion. Just as the pitch of a strummed string increases with its tension, the frequency and propagation speed of the Alfvén wave increases with the strength of the magnetic field.

"Just below the Sun's corona lies the so-called magnetic canopy, a layer in which magnetic fields are aligned largely parallel to the solar surface. Here, sound and Alfvén waves have roughly the same speed and can therefore easily morph into each other. We wanted to get to exactly this magic point -- where the shock-like transformation of the magnetic energy of the plasma into heat begins," says Stefani, outlining his team's goal.

A dangerous experiment?

Soon after their prediction in 1942, the Alfvén waves had been detected in first liquid-metal experiments and later studied in detail in elaborate plasma physics facilities. Only the conditions of the magnetic canopy, considered crucial for corona heating, remained inaccessible to experimenters until now. On the one hand, in large plasma experiments the Alfvén speed is typically much higher than the speed of sound. On the other hand, in all liquid-metal experiments to date, it has been significantly lower. The reason for this: the relatively low magnetic field strength of common superconducting coils with constant field of about 20 tesla.

But what about pulsed magnetic fields, such as those that can be generated at the HZDR's Dresden High Magnetic Field Laboratory (HLD) with maximum values of almost 100 tesla? This corresponds to about two million times the strength of the Earth's magnetic field: Would these extremely high fields allow Alfvén waves to break through the sound barrier? By looking at the properties of liquid metals, it was known in advance that the alkali metal rubidium actually reaches this magic point already at 54 tesla.

But rubidium ignites spontaneously in air and reacts violently with water. The team therefore initially had doubts as to whether such a dangerous experiment was advisable at all. The doubts were quickly dispelled, recalls Dr. Thomas Herrmannsdörfer of the HLD: "Our energy supply system for operating the pulse magnets converts 50 megajoules in a fraction of a second -- with that, we could theoretically get a commercial airliner to take off in a fraction of a second. When I explained to my colleagues that a thousandth of this amount of chemical energy of the liquid rubidium does not worry me very much, their facial expressions visibly brightened."

Pulsed through the magnetic sound barrier

Nevertheless, it was still a rocky road to the successful experiment. Because of the pressures of up to fifty times the atmospheric air pressure generated in the pulsed magnetic field, the rubidium melt had to be enclosed in a sturdy stainless steel container, which an experienced chemist, brought out of retirement, was to fill. By injecting alternating current at the bottom of the container while simultaneously exposing it to the magnetic field, it was finally possible to generate Alfvén waves in the melt, whose upward motion was measured at the expected speed.

The novelty: while up to the magic field strength of 54 tesla all measurements were dominated by the frequency of the alternating current signal, exactly at this point a new signal with halved frequency appeared. This sudden period doubling was in perfect agreement with the theoretical predictions. The Alfvén waves of Stefani's team had broken through the sound barrier for the first time. Although not all observed effects can yet be explained so easily, the work contributes an important detail to solving the puzzle of the Sun's corona heating. For the future, the researchers are planning detailed numerical analyses and further experiments.

Read more at Science Daily

Solving the disappearance of bears and lions with ancient DNA

An international team of researchers led by the University of Adelaide, suggest a change in climate is the likely cause of the mysterious disappearance of ancient lions and bears from parts of North America for a thousand years or more prior to the last Ice Age.

In a study in Molecular Ecology, the researchers sequenced DNA from fossils of cave lions and bears from North America and Eurasia to better understand the timing and drivers of their past movement between continents.

Co-author, Dr Kieren Mitchell from the University of Adelaide's Australian Centre for Ancient DNA said, "There's a common perception that outside of mass extinctions or direct human interference, ecosystems tend to remain stable over thousands or even millions of years.

"As illustrated by our study of the fossil record, that's not necessarily the case.

"Previous research has shown that brown bears (or grizzly bears) disappeared from some parts of North America for thousands of years prior to the last Ice Age. They later reappeared, walking from Russia to Alaska across the Bering Land Bridge -- possibly at the same time as people moved across the Bridge into North America too.

"But no-one knows exactly why they disappeared in the first place, which is why studying this event is important."

A key finding of the new research is that cave lions from the same area became extinct more than once -- before their final extinction they also disappeared and reappeared thousands of years later, around the same time as bears. There is no evidence that people caused these temporary disappearances, and cold Ice Age conditions were not to blame.

"Instead, it looks like a smoking gun pointing to some kind of change in their ecosystem," Dr Mitchell said.

The timing of lions and bear extinction from parts of North America (specifically Alaska and the Yukon Territory) coincides with evidence of widespread vegetation change in the region. The researchers suggest that warm temperatures before the last Ice Age may have caused a change in the abundance of different kinds of plants, which had knock-on effects on herbivores and then their predators (like bears and lions).

Colder temperatures leading up to the last Ice Age might have reversed this change and made the area more hospitable for herbivores, and in turn their predators.

"Overall, these findings demonstrate just how changeable past ecosystems have been, and also how the abundance of different species can be very sensitive to changes in climate," Dr Mitchell said.

Lead author from the University of Adelaide Dr Alexander Salis said: "The shared patterns of dispersal between lions and bears correspond with the presence of the Bering Land Bridge that connected Russia and Alaska during Ice Ages.

"The Bridge was periodically exposed and inundated by changing sea levels during the last few Ice Ages, allowing intermittent dispersal of animals and people between continents and changing the faunal composition.

Read more at Science Daily

Lychee genome tells a colorful story about a colorful tropical fruit

They're prickly on the outside, sweet on the inside, and beloved for their iconic pink shells and pearly, fragrant fruit. In the U.S., you might encounter them as a flavorful ingredient in bubble tea, ice cream or a cocktail. You can also peel them and eat them fresh.

Lychees have been grown in China since ancient times, with records of cultivation dating back about 2,000 years. Fresh lychees were an object of such desire that in the Tang Dynasty, one emperor set up a dedicated horse relay to deliver the fruits to the imperial court from harvests made far to the south.

Now, scientists have used genomics to peer even deeper into the lychee's history. And in the process, they've uncovered insights that could help shape the species' future, too.

"Lychee is an important tropical agricultural crop in the Sapindaceae (maple and horse chestnut) family, and it is one of the most economically significant fruit crops grown in eastern Asia, especially so to the yearly income of farmers in southern China," says Jianguo Li, PhD, professor in the South China Agricultural University (SCAU) College of Horticulture and a senior author of the study. "By sequencing and analyzing wild and cultivated lychee varieties, we were able to trace the origin and domestication history of lychee. We demonstrated that extremely early- and late-maturing cultivars were derived from independent human domestication events in Yunnan and Hainan, respectively."

Additionally, "We identified a specific genetic variant, a deleted stretch of genetic material, that can be developed as a simple biological marker for screening of lychee varieties with different flowering times, contributing importantly to future breeding programs," adds Rui Xia, PhD, professor in the same college at SCAU and another senior author of the research.

"Like a puzzle, we're piecing together the history of what humans did with lychee," says Victor Albert, PhD, University at Buffalo evolutionary biologist, also a senior author of the study. "These are the main stories our research tells: The origins of lychee, the idea that there were two separate domestications, and the discovery of a genetic deletion that we think causes different varieties to fruit and flower at different times."

The study will be published on Jan. 3 in Nature Genetics. It was led by SCAU in collaboration with a large international team from China, the U.S., Singapore, France and Canada.

Senior authors are Rui Xia, Jianguo Li and Houbin Chen from SCAU; Ray Ming from the University of Illinois at Urbana-Champaign; and Victor Albert from UB. First authors are Guibing Hu, Junting Feng, Chengming Liu and Zhenxian Wu from SCAU; Xu Xiang from the Guangdong Academy of Agricultural Sciences; Jiabao Wang from the Chinese Academy of Tropical Agricultural Sciences; and Jarkko Salojärvi from the Nanyang Technological University.

A fruit so beloved, it was domesticated more than once

To conduct the study, scientists produced a high-quality "reference genome" for a popular lychee cultivar called 'Feizixiao', and compared its DNA to that of other wild and farmed varieties. (All the cultivars belong to the same species, Litchi chinensis).

The research shows that the lychee tree, Litchi chinensis, was likely domesticated more than once: Wild lychees originated in Yunnan in southwestern China, spread east and south to Hainan Island, and then were domesticated independently in each of these two locations, the analysis suggests.

In Yunnan, people began cultivating very early-flowering varieties, and in Hainan, late-blooming varieties that bear fruit later in the year. Eventually, interbreeding between cultivars from these two regions led to hybrids, including varieties, like 'Feizixiao', that remain extremely popular today.

The exact timing of these events is uncertain. For instance, the study suggests that one milestone, the evolutionary split between L. chinensis populations in Yunnan and Hainan, which took place before domestication, could have occurred around 18,000 years ago. But that is only an estimate; other solutions are possible. Still, the analysis provides a fascinating look at the evolutionary history of lychees and their link with humans.

When will this lychee tree flower? A simple genetic test could tell

The study not only adds new chapters to the history of the lychee; it also provides an in-depth look at flowering time, a hugely important trait in agriculture.

"Early-maturing lychees versus late-maturing lychees came from different places and were domesticated independently," says Albert, PhD, Empire Innovation Professor of Biological Sciences in the UB College of Arts and Sciences. "This, by itself, is an interesting story, but we also wanted to know what causes these differences: Why do these varieties fruit and flower at different times?"

By comparing the DNA of many lychee varieties, the team identified a genetic variant that could be used to create a simple test for identifying early- and late-blooming lychee plants.

The variant is a deletion -- a chunk of missing DNA -- that lies near two genes associated with flowering, and may help to control the activity of one or both of them.

Yunnan cultivars that bloom very early have the deletion, inheriting it from both parents. Hainan varieties that mature late do not have it at all. And Feizixiao -- a hybrid with nearly equal amounts of DNA from each of the two regional populations -- is "heterozygous" for the deletion, meaning that it has only one copy inherited from one parent. This makes sense, as Feizixiao flowers early, but not extremely early.

"This is very useful for breeders. Because the lychee is perishable, flowering times have been important to extending the season for which the lychee is available in markets," Albert says.

Sequencing the lychee genome is only the start

The team at SCAU initiated the lychee genome study as part of a bigger project that hopes to greatly expand what we know about the DNA of important flowering plants within the same family, Sapindaceae.

"Sapindaceae is a large family that includes many economically important plants," Xia says. "So far, only a few of them, including lychee, longan, rambutan, yellowhorn and maple, have had their full genomes sequenced."

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First time genome editing made possible on cells lining blood vessel walls

The lab of Youyang Zhao, PhD, from Stanley Manne Children's Research Institute at Ann & Robert H. Lurie Children's Hospital of Chicago developed a unique nanoparticle to deliver genome editing technology, including CRISPR/Cas9, to endothelial cells, which are cells that line blood vessel walls. This is the first time that vascular endothelial cells could be reached for genome editing, since the usual way to deliver CRISPR/Cas9 -- through a virus -- does not work for this cell type. Findings were published in the journal Cell Reports.

"The nanoparticle we developed is a powerful new delivery system for genome editing in vascular endothelial cells, and could be used to treat many diseases, including acute respiratory distress syndrome from severe COVID-19," said senior author Dr. Zhao from Lurie Children's. "With this nanoparticle we can introduce genes to inhibit vascular injury and/or promote vascular repair, correct gene mutations and turn genes on or off to restore normal function. It also allows us to edit multiple genes at the same time. This is an important advance for treating any disease caused by endothelial dysfunction."

Endothelial dysfunction is at the root of many diseases, such as coronary artery disease, stroke, bronchopulmonary dysplasia and pulmonary artery hypertension. Dr. Zhao explained that genome editing in endothelial cells could even treat cancers by cutting off the blood supply to the tumor or blocking cancer metastasis.

At this stage, Dr. Zhao and colleagues achieved excellent results in a mouse model. The nanoparticle carrying CRISPR/Cas9 plasmid DNA was introduced via a one-time IV injection and required a few days to be effective. Preclinical testing will be necessary before clinical trials can begin.

"Our nanoparticle delivery system for genome editing and transgene expression also is a huge advance for cardiovascular research," added Dr. Zhao.

From Science Daily

Anthropologists study the energetics of uniquely human subsistence strategies

Among our closest living relatives -- the great apes -- we humans are unique: We have larger brains, reproduce more quickly and have longer life spans. These traits are obviously valuable, but the extra energy required to sustain them is quite significant. So how did we manage to afford them?

A group of anthropologists from UC Santa Barbara, the University of Utah and Duke University have teamed up on a research study to understand the strategies humans developed for obtaining that extra energy. Their findings are published in the current issue of Science.

Evolutionary success is largely determined by the extent to which an organism is effective at extracting energy (i.e. calories) from the environment and converting that energy into offspring. But energy acquisition is constrained by a number of factors, the primary being how much time and energy one can spend in the pursuit of food. Energy budgets represent the balance between energy intake and expenditure that all organisms must navigate in order to survive and reproduce.

"Because energy is such a fundamental currency, evolution has produced many astonishing energy-saving adaptations across the Tree of Life," said Thomas Kraft, the paper's lead author. Currently an assistant professor at the University of Utah, Kraft conducted the research while a postdoctoral student with Michael Gurven, senior author and professor of anthropology at UC Santa Barbara. "But that doesn't mean natural selection always favors reduced energy expenditure. In fact, tremendous variation exists in the 'tempo' of energetic strategies. A dramatic example is the difference between endothermic (warm-blooded) and ectothermic (cold-blooded) animals. Warm-blooded animals tend to use a lot more energy each day but are able to successfully channel that energy into activities that ultimately lead to successful reproduction."

The researchers began by comparing the amount of energy and time humans and other great apes expend in order to obtain all the foods they typically include in their diets. "We studied contemporary subsistence societies of hunter-gatherers and farmers in order to examine the kinds of energetic strategies that have existed for millennia, including those after the advent of plant domestication," said Kraft.

The team of scientists drew especially upon their long-term collective experience working with the Hadza, an indigenous group of foragers in northwest Tanzania, and the Tsimane, an indigenous group of horticulturalists in the Bolivian Amazon.

Compared to chimpanzees, gorillas and orangutans, human hunter-gatherers are not particularly efficient at acquiring food. "It turns out we spend a surprising amount of energy getting food because we walk very long distances and engage in intense activities such as digging tubers or clearing trees," explained Kraft. "Other great apes, in contrast, don't need to go very far each day. Most of their food shopping involves leisurely picking fruit and vegetation."

However, humans do benefit from earning a lot more food energy per hour. While other great apes don't cook their food and they spend exorbitant amounts of time chewing and digesting, humans' high-intensity subsistence activities yield many calories quickly.

"This is like saying that despite the intensity of the work, humans earn a much higher energetic 'salary' than do other apes," said Kraft. "This ability to attain a higher return rate is what makes hunter-gatherers so successful." Add farming to the mix and that rate of return -- or 'salary' -- only increases. "Those who mix farming with foraging double or triple what hunter-gatherers earn," Kraft continued. But high throughput human strategies, which involve expending a lot of energy to get more food faster, can also be quite risky if you fail to get food on a given day. "Yet humans seem uniquely able to overcome this by cooperating and sharing and storing foods to avoid dangerous shortfalls."

Such cooperation has other benefits as well. Being able to meet one's daily food requirement in less time would have provided more opportunities for other endeavors. "Developing the rich social and cultural life so common in all human societies may first have required time-efficient strategies for feeding yourself," said Gurven, who is also director of the UC Santa Barbara's Integrative Anthropological Sciences Unit and co-director of the Tsimane Health and Life History Project.

However, he noted, it also can lead us astray, contributing to health problems such as the current obesity epidemic. "Part of what makes us humans so successful is being really good at figuring out how to get the biggest return for the least effort," Gurven said. "You can see where that leads us today -- driving cars or taking a bus to the local Costco to purchase those tasty $4.99 rotisserie chickens. We've replaced our physical labor in hunting or farming with supply chains. If we evolved to get calories cheaply, then the need to eat less or move more may be a struggle for good reason."

On the other hand, he continued, the research findings suggest humans also evolved to be highly physically active, at least to attain food. "This doesn't mean we need to be vigorously active all the time," he said. "The lesson from subsistence populations is instead to just be less sedentary."

One finding from the study that surprised the researchers involved the high energetic costs of human subsistence strategies. Walking in an upright/bipedal form makes humans move more efficiently than the other great apes, and we use sophisticated tools to make tasks easier to accomplish. However, humans (both hunter-gatherers and farmers) actually expend more energy per day on activities related to acquiring food than do chimpanzees, gorillas and orangutans. This makes our subsistence strategies not very efficient overall.

Anthropology has a long tradition of collecting data on energy flows in different kinds of societies -- e.g. hunter-gatherers, horticulturalists, pastoralists. The researchers compiled these disparate data into a single database so they could ask whether the detailed data they had from the Hadza and the Tsimane were representative of broader patterns in subsistence energetics across societies. And they were, but other surprises came out of this exercise as well.

"We didn't expect that our cross-cultural database would reveal minimal difference in the amount of time spent working between hunter-gatherers and farming populations," he continued. As exemplified by James Suzman's recent book, "Work: A Deep History from the Stone Age to the Age of Robots," many anthropologists have long argued that hunter-gatherers spend very little time working as compared to other human societies. After compiling an exhaustive list of studies, the researchers found no evidence to support the idea that contemporary subsistence farmers spend more time working on average than hunter-gatherers.

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Safer carbon capture and storage

Atmospheric carbon dioxide (CO2) levels have increased significantly over the last 50 years, resulting in higher global temperatures and abrupt changes to Earth's climate. Carbon capture and storage (CCS) is one of the new technologies that scientists hope will play an important role in tackling the climate crisis. It involves the capture of CO2 from emissions from industrial processes, or from the burning of fossil fuels in power generation, which is then stored underground in geological formations. CCS will also be key if we want to produce "clean-burning" hydrogen from hydrocarbon systems.

The UK government recently selected four sites to develop multi-billion-pound CCS projects as part of its scheme to cut 20-30m tonnes of CO2 per year by 2030 from heavy industry. Other countries have made similar carbon reduction commitments.

Depleted hydrocarbon reservoirs have a smaller (10%) storage potential compared to deep saline aquifers but are seen as a critical early opportunity in developing geological CO2 storage technologies. Fortuitously, CO2 has historically been injected into numerous depleted hydrocarbon reservoirs as a means of enhanced oil recovery (CO2-EOR). This provides a unique chance to evaluate the (bio)geochemical behaviour of injected carbon over engineering timescales.

'CCS will be a key tool in our battle to avert climate change. Understanding how CCS works in practice, in addition tocomputer modelling and lab-based experiments, is essential to provide confidence in safe and secure CO2 geologicalsequestration.' Said Dr. Rebecca Tyne, Dept Earth Science, The University of Oxford

In a paper published, today in Nature, Dr. Rebecca Tyne and Prof. Chris Ballentine from Oxford University, lead a team of international collaborators to investigate the behaviour of CO2 within a CO2-EOR flooded oil field in Louisiana, USA. They compared (bio)geochemical composition of the CO2-EOR flooded field with that of an adjacent field, which was never subjected to CO2-EOR. Data suggest that up to 74% of CO2 left behind by CO2-EOR was dissolved in the groundwater. Unexpectedly, it also revealed, that microbial methanogenesis converted as much as 13-19% of the injected CO2 to methane, which is a stronger greenhouse gas than CO2.

This study is the first to integrate state of the art isotopic tracers (noble gas, clumped and stable isotope data) with microbiological data to investigate the fate of the injected CO2.

'Methane is less soluble, less compressible and less reactive than CO2, so, if produced, the reduces the amount of CO2 we can safely inject into these sites. However, now this process has been identified, we can take it into account in future CCS site selection.' Said Prof. Chris Ballentine, Dept. Earth Sciences, The University of Oxford.

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Nits on ancient mummies shed light on South American ancestry

Human DNA can be extracted from the 'cement' head lice used to glue their eggs to hairs thousands of years ago, scientists have found, which could provide an important new window into the past.

In a new study, scientists for the first time recovered DNA from cement on hairs taken from mummified remains that date back 1,500-2,000 years. This is possible because skin cells from the scalp become encased in the cement produced by female lice as they attach eggs, known as nits, to the hair.

Analysis of this newly-recovered ancient DNA -- which was of better quality than that recovered through other methods -- has revealed clues about pre-Columbian human migration patterns within South America. This method could allow many more unique samples to be studied from human remains where bone and tooth samples are unavailable.

The research was led by the University of Reading, working in collaboration with the National University of San Juan, Argentina; Bangor University, Wales; the Oxford University Museum of Natural History; and the University of Copenhagen, Denmark. It is published in the journal Molecular Biology and Evolution.

Dr Alejandra Perotti, Associate Professor in Invertebrate Biology at the University of Reading, who led the research, said: "Like the fictional story of mosquitos encased in amber in the film Jurassic Park, carrying the DNA of the dinosaur host, we have shown that our genetic information can be preserved by the sticky substance produced by headlice on our hair. In addition to genetics, lice biology can provide valuable clues about how people lived and died thousands of years ago.

"Demand for DNA samples from ancient human remains has grown in recent years as we seek to understand migration and diversity in ancient human populations. Headlice have accompanied humans throughout their entire existence, so this new method could open the door to a goldmine of information about our ancestors, while preserving unique specimens."

Until now, ancient DNA has preferably been extracted from dense bone from the skull or from inside teeth, as these provide the best quality samples. However, skull and teeth remains are not always available, as it can be unethical or against cultural beliefs to take samples from indigenous early remains, and due to the severe damage destructive sampling causes to the specimens which compromise future scientific analysis.

Recovering DNA from the cement delivered by lice is therefore a solution to the problem, especially as nits are commonly found on the hair and clothes of well preserved and mummified humans.

The research team extracted DNA from nit cement of specimens collected from a number of mummified remains from Argentina. The mummies were of people who 1,500-2,000 years ago reached the Andes mountains of the San Juan province, Central West Argentina. The team also studied ancient nits on human hair used in a textile from Chile and nits from a shrunken head originating from the ancient Jivaroan people of Amazonian Ecuador.

The samples used for DNA studies of nit cement were found to contain the same concentration of DNA as a tooth, double that of bone remains, and four times that recovered from blood inside far more recent lice specimens.

Dr Mikkel Winther Pedersen from the GLOBE institute at the University of Copenhagen, and first author, said: "The high amount of DNA yield from these nit cements really came as a surprise to us and it was striking to me that such small amounts could still give us all this information about who these people were, and how the lice related to other lice species but also giving us hints to possible viral diseases.

"There is a hunt out for alternative sources of ancient human DNA and nit cement might be one of those alternatives. I believe that future studies are needed before we really unravel this potential."

Read more at Science Daily

Leveraging space to advance stem cell science and medicine

The secret to producing large batches of stem cells more efficiently may lie in the near-zero gravity conditions of space. Scientists at Cedars-Sinai have found that microgravity has the potential to contribute to life-saving advances on Earth by facilitating the rapid mass production of stem cells.

A new paper, led by Cedars Sinai and published in the peer-review journal Stem Cell Reports, highlights key opportunities discussed during the 2020 Biomanufacturing in Space Symposium to expand the manufacture of stem cells in space.

Biomanufacturing -- a type of stem cell production that uses biological materials such as microbes to produce substances and biomaterials suitable for use in preclinical, clinical, and therapeutic applications -- can be more productive in microgravity conditions.

"We are finding that spaceflight and microgravity is a desirable place for biomanufacturing because it confers a number of very special properties to biological tissues and biological processes that can help mass produce cells or other products in a way that you wouldn't be able to do on Earth," said stem cell biologist Arun Sharma, PhD, research scientist and head of a new research laboratory in the Cedars-Sinai Board of Governors Regenerative Medicine Institute, Smidt Heart Institute and Department of Biomedical Sciences.

"The last two decades have seen remarkable advances in regenerative medicine and exponential advancement in space technologies enabling new opportunities to access and commercialize space," he said.

Attendees at the virtual space symposium in December identified more than 50 potential commercial opportunities for conducting biomanufacturing work in space, according to the Cedars-Sinai paper. The most promising fell into three categories: disease modeling, biofabrication, and stem-cell-derived products.

The first, disease modeling, is used by scientists to study diseases and possible treatments by replicating full-function structures -- whether using stem cells, organoids (miniature 3D structures grown from human stem cells that resemble human tissue), or other tissues.

Investigators have found that once the body is exposed to low-gravity conditions for extended periods of time, it experiences accelerated bone loss and aging. By developing disease models based on this accelerated aging process, research scientists can better understand the mechanisms of the aging process and disease progression.

"Not only can this work help astronauts, but it can also lead to us manufacturing bone constructs or skeletal muscle constructs that could be applied to diseases like osteoporosis and other forms of accelerated bone aging and muscle wasting that people experience on Earth," said Sharma, who is the corresponding author of the paper.

Another highly discussed topic at the symposium was biofabrication, which uses manufacturing processes to produce materials like tissues and organs. 3D printing is one of the core biofabrication technologies.

A major issue with producing these materials on Earth involves gravity-induced density, which makes it hard for cells to expand and grow. With the absence of gravity and density in space, scientists are hopeful that they can use 3D printing to print unique shapes and products, like organoids or cardiac tissues, in a way that can't be replicated on Earth.

The third category has to do with the production of stem cells and understanding how some of their fundamental properties are influenced by microgravity. Some of these properties include potency, or the ability of a stem cell to renew itself, and differentiation, the ability for stem cells to turn into other cell types.

Understanding some of the effects of spaceflight on stem cells can potentially lead to better ways to manufacture large numbers of cells in the absence of gravity. Scientists from Cedars-Sinai will be sending stem cells into space early next year, in conjunction with NASA and a private contractor, Space Tango, to test whether it is possible to produce large batches in a low gravity environment.

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