Happiness and the evolution of brain size

 During human evolution, the size of the brain increased, especially in a particular part called the neocortex. The neocortex enables us to speak, dream and think. In search of the causes underlying neocortex expansion, researchers at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, together with colleagues at the University Hospital Carl Gustav Carus Dresden, previously identified a number of molecular players. These players typically act cell-intrinsically in the so-called basal progenitors, the stem cells in the developing neocortex with a pivotal role in its expansion. The researchers now report an additional, novel role of the happiness neurotransmitter serotonin which is known to function in the brain to mediate satisfaction, self-confidence and optimism -- to act cell-extrinsically as a growth factor for basal progenitors in the developing human, but not mouse, neocortex. Due to this new function, placenta-derived serotonin likely contributed to the evolutionary expansion of the human neocortex.

The research team of Wieland Huttner at the Max Planck Institute of Molecular Cell Biology and Genetics, who is one of the institute's founding directors, has investigated the cause of the evolutionary expansion of the human neocortex in many studies. A new study from his lab focuses on the role of the neurotransmitter serotonin in this process. Serotonin is often called the happiness neurotransmitter because it transmits messages between nerve cells that contribute to well-being and happiness. However, a potential role of such neurotransmitters during brain development has not yet been explored in detail. In the developing embryo, the placenta produces serotonin, which then reaches the brain via the blood circulation. This is true for humans as well as mice. Yet, the function of this placenta-derived serotonin in the developing brain has been unknown.

The postdoctoral researcher Lei Xing in the Huttner group had studied neurotransmitters during his doctoral work in Canada. When he started his research project in Dresden after that, he was curious to investigate their role in the developing brain. Lei Xing says: "I exploited datasets generated by the group in the past and found that the serotonin receptor HTR2A was expressed in fetal human, but not embryonic mouse, neocortex. Serotonin needs to bind to this receptor in order to activate downstream signaling. I asked myself if this receptor could be one of the keys to the question of why humans have a bigger brain." To explore this, the researchers induced the production of the HTR2A receptor in embryonic mouse neocortex. "Indeed, we found that serotonin, by activating this receptor, caused a chain of reactions that resulted in the production of more basal progenitors in the developing brain. More basal progenitors can then increase the production of cortical neurons, which paves the way to a bigger brain," continues Lei Xing.

Significance for brain development and evolution

"In conclusion, our study uncovers a novel role of serotonin as a growth factor for basal progenitors in highly developed brains, notably human. Our data implicate serotonin in the expansion of the neocortex during development and human evolution," summarizes Wieland Huttner, who supervised the study. He continues: "Abnormal signaling of serotonin and a disturbed expression or mutation of its receptor HTR2A have been observed in various neurodevelopmental and psychiatric disorders, such as Down syndrome, attention deficit hyperactivity disorder and autism. Our findings may help explain how malfunctions of serotonin and its receptor during fetal brain development can lead to congenital disorders and may suggest novel approaches for therapeutic avenues."

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New imaging method reveals HIV's sugary shield in unprecedented detail

 Scientists from Scripps Research and Los Alamos National Laboratory have devised a method for mapping in unprecedented detail the thickets of slippery sugar molecules that help shield HIV from the immune system.

Mapping these shields will give researchers a more complete understanding of why antibodies react to some spots on the virus but not others, and may shape the design of new vaccines that target the most vulnerable and accessible sites on HIV and other viruses.

The sugar molecules, or "glycans," are loose and stringy, and function as shields because they are difficult for antibodies to grip and block access to the protein surface. The shields form on the outermost spike proteins of HIV and many other viruses, including SARS-CoV-2, the coronavirus that causes COVID-19, because these viruses have evolved sites on their spike proteins where glycan molecules -- normally abundant in cells -- will automatically attach.

"We now have a way to capture the full structures of these constantly fluctuating glycan shields, which to a great extent determine where antibodies can and can't bind to a virus such as HIV," says the study's lead author Zachary Berndsen, PhD, a postdoctoral research associate in the structural biology lab of Scripps Research Professor Andrew Ward, PhD.

The same wavy flexibility that makes these sugary molecules resistant to antibodies has made them impossible for researchers to capture with traditional atomic-scale imaging. In the new study, which appears in the Proceedings of the National Academy of Sciences, the scientists developed techniques that, for the first time, allow these elusive molecules to be mapped in great detail on the surface of the HIV spike protein, known as "Env."

The Scripps Research team collaborated with the lab of Gnana Gnanakaran, PhD, staff scientist at Los Alamos National Laboratory, which is equipped with high-performance computing resources that enabled fresh approaches for modeling the glycans.

The researchers combined an atomic-scale imaging method called cryo-electron microscopy (cryo-EM) with sophisticated computer modeling and a molecule-identifying technique called site-specific mass spectrometry. Cryo-EM relies on averaging tens or hundreds of thousands of individual snapshots to create a clear image, thus highly flexible molecules like glycans will appear only as a blur, if they show up at all.

But by integrating cryo-EM with the other technologies, the researchers were able to recover this lost glycan signal and use it to map sites of vulnerability on the surface of Env.

"This is the first time that cryo-EM has been used along with computational modeling to describe the viral shield structure in atomic detail," says Srirupa Chakraborty, PhD, co-lead author and post-doctoral researcher in the Gnanakaran lab at Los Alamos National Laboratory.

The new combined approach revealed the glycans' structure and dynamic nature in extreme detail and helped the team better understand how these complex dynamics affect the features observed in the cryo-EM maps. From this wealth of information, the team observed that individual glycans do not just wiggle around randomly on the spike protein's surface, as once was thought, but instead clump together in tufts and thickets.

"There are chunks of glycans that seem to move and interact together," Berndsen says. "In between these glycan microdomains is where antibodies apparently have the opportunity to bind."

Experimental HIV vaccines rely on modified, lab-made Env proteins to elicit antibody responses. In principle, these vaccines' effectiveness depends in part on the positioning and extent of the shielding glycans on these lab-made viral proteins. Therefore, Berndsen and colleagues applied their method to map the glycans on a modified HIV Env protein, BG505 SOSIP.664, which is used in an HIV vaccine currently being evaluated in clinical trials.

"We found spots on the surface of this protein that normally would be covered with glycans but weren't -- and that may explain why antibody responses to that site have been noted in vaccination trials," Berndsen says.

That finding, and others in the study, showed that Env's glycan shield can vary depending on what type of cell is being used to produce it. In HIV's infections of humans, the virus uses human immune cells as factories to replicate its proteins. But viral proteins used to make vaccines normally are produced in other types of mammalian cells.

In another surprise discovery, the team observed that when they used enzymes to slowly remove glycans from HIV Env, the entire protein began to fall apart. Berndsen and colleagues suspect that Env's glycan shield, which has been considered merely a defense against antibodies, may also have a role in managing Env's shape and stability, keeping it poised for infection.

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Galactic archaeology

 No one has yet found the first stars.

They're hypothesized to have formed about 100 million years after the Big Bang out of universal darkness from the primordial gases of hydrogen, helium, and trace light metals. These gases cooled, collapsed, and ignited into stars up to 1,000 times more massive than our sun. The bigger the star, the faster they burn out. The first stars probably only lived a few million years, a drop in the bucket of the age of the universe, at about 13.8 billion years. They're unlikely to ever be observed, lost to the mists of time.

As the metal-free first stars collapsed and exploded into supernovae, they forged heavier elements such as carbon that seeded the next generation of stars. One type of these second stars is called a carbon-enhanced metal-poor star. They're like fossils to astrophysicists. Their composition reflects the nucleosynthesis, or fusion, of heavier elements from the first stars.

"We can get results from indirect measurements to get the mass distribution of metal-free stars from the elemental abundances of metal-poor stars," said Gen Chiaki, a post-doctoral researcher in the Center for Relativistic Astrophysics, School of Physics, Georgia Tech.

Chiaki is the lead author of a study published in the September 2020 issue of the Monthly Notices of the Royal Astronomical Society. The study modeled for the first time faint supernovae of metal-free first stars, which yielded carbon-enhanced abundance patterns through the mixing and fallback of the ejected bits.

Their simulations also showed the carbonaceous grains seeding the fragmentation of the gas cloud produced, leading to formation of low-mass 'giga-metal-poor' stars that can survive to the present day and possibly be found in future observations.

"We find that these stars have very low iron content compared to the observed carbon-enhanced stars with billionths of the solar abundance of iron. However, we can see the fragmentation of the clouds of gas. This indicates that the low mass stars form in a low iron abundance regime. Such stars have never been observed yet. Our study gives us theoretical insight of the formation of first stars," Chiaki said.

The investigations of Wise and Chiaki are a part of a field called 'galactic archaeology.' They liken it to searching for artifacts underground that tell about the character of societies long gone. To astrophysicists, the character of long-gone stars can be revealed from their fossilized remains.

"We can't see the very first generations of stars," said study co-author John Wise, an associate professor also at the Center for Relativistic Astrophysics, School of Physics, Georgia Tech. "Therefore, it's important to actually look at these living fossils from the early universe, because they have the fingerprints of the first stars all over them through the chemicals that were produced in the supernova from the first stars."

"These old stars have some fingerprints of the nucleosynthesis of metal-free stars. It's a hint for us to seek the nucleosynthesis mechanism happening in the early universe," Chiaki said.

"That's where our simulations come into play to see this happening. After you run the simulation, you can watch a short movie of it to see where the metals come from and how the first stars and their supernovae actually affect these fossils that live until the present day," Wise said.

The scientists first modeled the formation of their first star, called a Population III or Pop III star, and ran three different simulations that corresponded to its mass at 13.5, 50, and 80 solar masses. The simulations solved for the radiative transfer during its main sequence and then after it dies and goes supernova. The last step was to evolve the collapse of the cloud of molecules spewed out by the supernova that involved a chemical network of 100 reactions and 50 species such as carbon monoxide and water.

The majority of the simulations ran on the Georgia Tech PACE cluster. They were also awarded computer allocations by the National Science Foundation (NSF)-funded Extreme Science and Engineering Discovery Environment (XSEDE). Stampede2 at the Texas Advanced Computing Center (TACC) and Comet at the San Diego Supercomputer Center (SDSC) ran some of the main sequence radiative transfer simulations through XSEDE allocations.

"The XSEDE systems Comet at SDSC and Stampede2 at TACC are very fast and have a large storage system. They were very suitable to conduct our huge numerical simulations," Chiaki said.

"Because Stampede2 is just so large, even though it has to accommodate thousands of researchers, it's still an invaluable resource for us," Wise said. "We can't just run our simulations on local machines at Georgia Tech."

Chiaki said he was also happy with the fast queues on Comet at SDSC. "On Comet, I could immediately run the simulations just after I submitted the job," he said.

Wise has been using XSEDE system allocations for over a decade, starting when he was a postdoc. "I couldn't have done my research without XSEDE."

XSEDE also provided expertise for the researchers to take full advantage of their supercomputer allocations through the Extended Collaborative Support Services (ECSS) program. Wise recalled using ECSS several years ago to improve the performance of the Enzo adaptive mesh refinement simulation code he still uses to solve the radiative transfer of stellar radiation and supernovae.

"Through ECSS, I worked with Lars Koesterke at TACC, and I found out that he used to work in astrophysics. He worked with me to improve the performance by about 50 percent of the radiation transport solver. He helped me profile the code to pinpoint which loops were taking the most time, and how to speed it up by reordering some loops. I don't think I would have identified that change without his help," Wise said.

Wise has also been awarded time on TACC's NSF-funded Frontera system, the fastest academic supercomputer in the world. "We haven't gotten to full steam yet on Frontera. But we're looking forward to using it, because that's even a larger, more capable resource."

Wise added: "We're all working on the next generation of Enzo. We call it Enzo-E, E for exascale. This is a total re-write of Enzo by James Bordner, a computer scientist at the San Diego Supercomputer Center. And it scales almost perfectly to 256,000 cores so far. That was run on NSF's Blue Waters. I think he scaled it to the same amount on Frontera, but Frontera is bigger, so I want to see how far it can go."

The downside, he said, is that since the code is new, it doesn't have all the physics they need yet. "We're about two-thirds of the way there," Wise said.

He said that he's also hoping to get access to the new Expanse system at SDSC, which will supersede Comet after it retires in the next year or so. "Expanse has over double the compute cores per node than any other XSEDE resource, which will hopefully speed up our simulations by reducing the communication time between cores," Wise said.

According to Chiaki, the next steps in the research are to branch out beyond the carbon features of ancient stars. "We want to enlarge our interest to the other types of stars and the general elements with larger simulations," he said.

Read more at Science Daily

Charging electric cars up to 90% in 6 minutes

 With Telsa in the lead, the electric vehicle market is growing around the world. Unlike conventional cars that use internal combustion engines, electric cars are solely powered by lithium ion batteries, so the battery performance defines the car's overall performance. However, slow charging times and weak power are still barriers to be overcome. In light of this, a POSTECH research team has recently developed a faster charging and longer lasting battery material for electric cars.

The research teams of Professor Byoungwoo Kang and Dr. Minkyung Kim of the Department of Materials Science and Engineering at POSTECH and Professor Won-Sub Yoon in the Department of Energy Science at Sungkyunkwan University have together proved for the first time that when charging and discharging Li-ion battery electrode materials, high power can be produced by significantly reducing the charging and discharging time without reducing the particle size. These research findings were published in the recent issue of Energy & Environmental Science, a leading international journal in the energy materials field.

For fast charging and discharging of Li-ion batteries, methods that reduce the particle size of electrode materials were used so far. However, reducing the particle size has a disadvantage of decreasing the volumetric energy density of the batteries.

To this, the research team confirmed that if an intermediate phase in the phase transition is formed during the charging and discharging, high power can be generated without losing high energy density or reducing the particle size through rapid charging and discharging, enabling the development of long-lasting Li-ion batteries.

In the case of phase separating materials that undergo the process of creating and growing new phases while charging and discharging, two phases with different volumes exist within a single particle, resulting in many structural defects in the interface of the two phases. These defects inhibit the rapid growth of a new phase within the particle, hindering quick charging and discharging.

Using the synthesis method developed by the research team, one can induce an intermediate phase that acts as a structural buffer that can dramatically reduce the change in volume between the two phases in a particle.

In addition, it has been confirmed that this buffering intermediate phase can help create and grow a new phase within the particle, improving the speed of insertion and removal of lithium in the particle. This in turn proved that the intermediate phase formation can dramatically increase the charging and discharging speed of the cell by creating a homogenous electrochemical reaction in the electrode where numerous particles is composed of. As a result, the Li-ion battery electrodes synthesized by the research team charge up to 90% in six minutes and discharge 54% in 18 seconds, a promising sign for developing high-power Li-ion batteries.

"The conventional approach has always been a trade-off between its low energy density and the rapid charge and discharge speed due to the reduction in the particle size," remarked Professor Byoungwoo Kang, the corresponding author of the paper. He elaborated, "This research has laid the foundation for developing Li-ion batteries that can achieve quick charging and discharging speed, high energy density, and prolonged performance."

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How'd we get so picky about friendship late in life? Ask the chimps

 No new friends and no drama.

When humans age, they tend to favor small circles of meaningful, already established friendships rather than seek new ones. People are also more likely to lean toward positive relationships rather than ones that bring tension or conflict. These behaviors were thought to be unique to humans but it turns out chimpanzees, one of our closest living relatives, have these traits, too. Understanding why can help scientists gain a better picture of what healthy aging should look like and what triggers this social change.

The work is described in the journal Science and is authored by a team of psychologists and primatologists, including current and former researchers from the Harvard Department of Human Evolutionary Biology.

The study draws on 78,000 hours of observations, made between 1995 and 2016, which looked at the social interactions of 21 male chimpanzees between the ages of 15 and 58 years old in the Kibale National Park in Uganda. It shows what's believed to be the first evidence of nonhuman animals actively selecting who they socialize with during aging.

The researchers looked only at male chimpanzees because they show stronger social bonds and have more frequent social interactions than female chimps.

Analyzing a trove of data, the researchers saw that the chimpanzees displayed much of the same behavior aging humans exhibit. The older chimpanzees they studied, for instance, preferred spending more time with -- and grooming -- chimps they'd developed mutual friendships with over the years while younger chimps had more one-sided relationships where grooming wasn't always returned. Older males were also more likely to spend more time alone but interacted with more important social partners, like their aging mutual friends. And like older humans looking for some peace and quiet, the chimpanzees also showed a shift from negative interactions to more positive ones as they reached their twilight years. The preference is known as a positivity bias.

"The really cool thing is that we found that chimpanzees are showing these patterns that mirror those of humans," said Alexandra Rosati '05, an assistant professor of psychology and anthropology at the University of Michigan and one of the paper's lead authors.

Through future research that can help determine if these behaviors constitute the normal or successful course that aging should take, she added. It can serve as a model or baseline.

"There's really a pressing need to understand the biology of aging," Rosati said. "More humans are living longer than in the past, which can change the dynamics of aging."

Rosati is a former assistant professor and visiting fellow in HEB department where the study originated. Other Harvard-connected authors on the paper include Zarin Machanda '04, A.M., '09, Ph.D. who's now an assistant professor at Tufts University, Melissa Emery Thompson '00, A.M, '05, Ph.D., who's now an associate professor at New Mexico University, Lindsey Hagberg '17, who's now a medical student at Washington University, and Richard W. Wrangham, Ruth B. Moore Professor of Biological Anthropology and founder and co-director of the Kibale Chimpanzee Project.

Machanda and Thompson worked in Wrangham's lab as graduate students and currently serve as co-directors for the Kibale project, which has other authors on the paper including Martin N. Muller, a former postdoctoral-fellow in HEB. The project started as Hagberg's undergraduate senior thesis.

The study tested the origins of humans prioritizing close, positive relationships during aging and if it's really triggered by a theory known as socioemotional selectivity. The notion suggests that the central process driving social selectivity during aging results from people becoming aware that their time is running out and wanting to make the best of that time.

The findings from the study suggest there is more to understand.

"Even though chimps are very smart, they do not understand they're going to die," Wrangham said. "Much more likely something else is going on in chimps to explain why their relationships become more positive as they get older, and then the question is what applies to chimps the same as what applies to humans."

Some of the observations that led the researchers to their conclusions included looking at proximity and grooming habits. Older chimps preferred sitting close to those who preferred sitting close to them. These are categorized as mutual friendships while one-sided friendships are when one chimp prefers sitting close to another chimp but that other chimp doesn't share that habit.

Fifteen-year-old chimps had on average 2.1 one-sided friendships and 0.9 mutual friends while 40-year-old chimps almost didn't bother with one-side friendships (their average was .6), but did have plenty of mutual friends, an average of three. By looking at grooming habits, the researchers then saw the older chimps devote more energy into their relationships with mutual friends.

"We see individuals having these more lopsided friendships and then as they age they start really spending time with individuals that reciprocate," said Machanda, who was the paper's other lead author. "When you have this kind of mutual friendship, you actually groom that individual more, so these older chimps have these mutual friendships and they're actually grooming those individuals quite a bit. They're really invested in these relationships."

The scientists weren't entirely surprised by their findings. Part of it is because chimpanzees and humans are already a lot alike in terms of social organization and social choices. After all, chimpanzees, along with bonobos, share 99 percent of their DNA with humans.

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Turbulent era sparked leap in human behavior, adaptability 320,000 years ago

 

Rift Valley

For hundreds of thousands of years, early humans in the East African Rift Valley could expect certain things of their environment. Freshwater lakes in the region ensured a reliable source of water, and large grazing herbivores roamed the grasslands. Then, around 400,000 years ago, things changed. The environment became less predictable, and human ancestors faced new sources of instability and uncertainty that challenged their previous long-standing way of life.

The first analysis of a new sedimentary drill core representing 1 million years of environmental history in the East African Rift Valley shows that at the same time early humans were abandoning old tools in favor of more sophisticated technology and broadening their trade networks, their landscape was experiencing frequent fluctuations in vegetation and water supply that made resources less reliably available. The findings suggest that instability in their surrounding climate, land and ecosystem was a key driver in the development of new traits and behaviors underpinning human adaptability.

In the Oct. 21 issue of the journal Science Advances, an interdisciplinary team of scientists led by Richard Potts, director of the Human Origins Program at the Smithsonian's National Museum of Natural History, describes the prolonged period of instability across the landscape in this part of Africa (now Kenya) that occurred at the same time humans in the region were undergoing a major behavioral and cultural shift in their evolution.

Potts and colleagues documented this behavioral and cultural shift in 2018 based on artifacts recovered at an archaeological site known as Olorgesailie. Decades of study at Olorgesailie by Potts' team and collaborators at the National Museums of Kenya have determined that early humans at Olorgesailie relied on the same tools, stone handaxes, for 700,000 years. Their way of life during this period was remarkably stable, with no major changes in their behaviors and strategies for survival. Then, beginning around 320,000 years ago, people living there entered the Middle Stone Age, crafting smaller, more sophisticated weapons, including projectiles. At the same time, they began to trade resources with distant groups and to use coloring materials, suggesting symbolic communication. All these changes were a significant departure from their previous lifestyle, likely helping early humans cope with their newly variable landscape, Potts said.

"The history of human evolution has been one of increasing adaptability," Potts said. "We come from a family tree that's diverse, but all of those other ways of being human are now extinct. There's only one of us left, and we may well be the most adaptable species that may have ever existed on the face of the Earth."

While some scientists have proposed that climate fluctuations alone may have driven humans to evolve this remarkable quality of adaptability, the new study indicates the picture is more complicated than that. Instead, the team's analysis shows that climate variability is but one of several intertwined environmental factors that drove the cultural shift they described in 2018. The new analysis reveals how a changing climate along with new land faults introduced by tectonic activity and ecological disruptions in the vegetation and fauna all came together to drive disruptions that made technological innovation, trading resources and symbolic communication¬ -- three key factors in adaptability -- beneficial for early humans in this region.

In seeking to understand the major evolutionary transition they had uncovered at Olorgesailie, Potts and his team had been frustrated by a large gap in the region's environmental record. Erosion at Olorgesailie, a hilly area full of sedimentary outcrops, had removed the geologic layers representing some 180,000 years of time at exactly the period of this evolutionary transition. To learn about how the region changed during that period, they had to look elsewhere.

They arranged to have a Nairobi company drill in the nearby Koora basin, extracting sediment from as deep into the earth as they could. The drill site, about 15 miles from the archaeological dig sites, was a flat, grassy plain, and the team had no clear idea what was beneath its surface. With the involvement and support from the National Museums of Kenya and the local Oldonyo Nyokie community, a 139-meter core was removed from the earth. That cylinder of earth, just four centimeters in diameter, turned out to represent 1 million years of environmental history.

Colleagues in the National Museum of Natural History's Human Origins Program and Department of Paleobiology and dozens of collaborators at institutions worldwide worked to analyze the environmental record they had obtained, which is now the most precisely dated African environmental record of the past 1 million years. Charting radioisotope ages and changes in chemical composition and deposits left by plants and microscopic organisms through the different layers of the core, the team reconstructed key features of the ancient landscape and climate across time.

They found that after a long period of stability, the environment in this part of Africa became more variable around 400,000 years ago, when tectonic activity fragmented the landscape. By integrating information from the drill core with knowledge gleaned from fossils and archeological artifacts, they determined that the entire ecosystem evolved in response.

The team's analysis suggests that as parts of the grassy plains in the region were fragmented along fault lines due to tectonic activity, small basins formed. These areas were more sensitive to changes in rainfall than the larger lake basins that had been there before. Elevated terrain also allowed water runoff from high ground to contribute to the formation and drying out of lakes. These changes occurred during a period when precipitation had become more variable, leading to frequent and dramatic fluctuations in water supply.

With the fluctuations, a broader set of ecological changes also took place. The team found that vegetation in the region also changed repeatedly, shifting between grassy plains and wooded areas. Meanwhile, large grazing herbivores, which no longer had large tracts of grass to feed on, began to die out and were replaced by smaller mammals with more diverse diets.

"There was a massive change in the animal fauna during the time period when we see early human behavior changing," Potts said. "The animals also influenced the landscape through the kinds of plants that they ate. Then with humans in the mix, and some of their innovations like projectile weapons, they also may have affected the fauna. It's a whole ecosystem changing, with humans as part of it."

Finally, Potts notes that while adaptability is a hallmark of human evolution, that does not mean the species is necessarily equipped to endure the unprecedented change Earth is now experiencing due to man-made climate change and Anthropogenic biodiversity loss. "We have an astonishing capacity to adapt, biologically in our genes as well as culturally and socially," he said. "The question is, are we now creating through our own activities new sources of environmental disruption that will continue to challenge human adaptability?"

Read more at Science Daily

Smile, wave: Some exoplanets may be able to see us, too

 Three decades after Cornell astronomer Carl Sagan suggested that Voyager 1 snap Earth's picture from billions of miles away -- resulting in the iconic Pale Blue Dot photograph -- two astronomers now offer another unique cosmic perspective: Some exoplanets -- planets from beyond our own solar system -- have a direct line of sight to observe Earth's biological qualities from far, far away.

Lisa Kaltenegger, associate professor of astronomy at Cornell University and director of Cornell's Carl Sagan Institute; and Joshua Pepper, associate professor of physics at Lehigh University, have identified 1,004 main-sequence stars (similar to our sun) that might contain Earth-like planets in their own habitable zones -- all within about 300 light-years of Earth -- and which should be able to detect Earth's chemical traces of life.

The paper, "Which Stars Can See Earth as a Transiting Exoplanet?" was published in the Monthly Notices of the Royal Astronomical Society.

"Let's reverse the viewpoint to that of other stars and ask from which vantage point other observers could find Earth as a transiting planet," Kaltenegger said. A transiting planet is one that passes through the observer's line of sight to another star, such as the sun, revealing clues as to the makeup of the planet's atmosphere.

"If observers were out there searching, they would be able to see signs of a biosphere in the atmosphere of our Pale Blue Dot," she said, "And we can even see some of the brightest of these stars in our night sky without binoculars or telescopes."

Transit observations are a crucial tool for Earth's astronomers to characterize inhabited extrasolar planets, Kaltenegger said, which astronomers will start to use with the launch of NASA's James Webb Space telescope next year.

But which star systems could find us? Holding the key to this science is Earth's ecliptic -- the plane of Earth's orbit around the Sun. The ecliptic is where the exoplanets with a view of Earth would be located, as they will be the places able to see Earth crossing its own sun -- effectively providing observers a way to discover our planet's vibrant biosphere.

Pepper and Kaltenegger created the list of the thousand closest stars using NASA's Transiting Exoplanet Survey Satellite (TESS) star catalog .

"Only a very small fraction of exoplanets will just happen to be randomly aligned with our line of sight so we can see them transit." Pepper said. "But all of the thousand stars we identified in our paper in the solar neighborhood could see our Earth transit the sun, calling their attention."

"If we found a planet with a vibrant biosphere, we would get curious about whether or not someone is there looking at us too," Kaltenegger said.

"If we're looking for intelligent life in the universe, that could find us and might want to get in touch" she said, "we've just created the star map of where we should look first."

 Read more at Science Daily

Vitamin A boosts fat burning in cold conditions

 A recent study conducted by a research team led by Florian Kiefer from MedUni Vienna's Division of Endocrinology and Metabolism shows that cold ambient temperatures increase vitamin A levels in humans and mice. This helps convert "bad" white adipose tissue into "good" brown adipose tissue which stimulates fat burning and heat generation. This "fat transformation" is usually accompanied by enhanced energy consumption and is therefore considered a promising approach for the development of novel obesity therapeutics. The study has now been published in the journal Molecular Metabolism.

In humans and mammals, at least two types of fatty depots can be discerned, white and brown adipose tissue. During obesity development, excess calories are mainly stored in white fat. In contrast, brown fat burns energy and thereby generates heat. More than 90% of the body fat depots in humans are white which are typically located at the abdomen, bottom, and upper thighs. Converting white into brown fat could be a new therapeutic option to combat weight gain and obesity.

A research group led by Florian Kiefer from the Division of Endocrinology and Metabolism, Department of Medicine III at MedUni Vienna demonstrated now that moderate application of cold increases the levels of vitamin A and its blood transporter, retinol-binding protein, in humans and mice. Most of the vitamin A reserves are stored in the liver and cold exposure seems to stimulate the redistribution of vitamin A towards the adipose tissue. The cold-induced increase in vitamin A led to a conversion of white fat into brown fat ("browning"), with a higher rate of fat burning.

When Kiefer and his team blocked the vitamin A transporter "retinol-binding protein" in mice by genetic manipulation, both the cold-mediated rise in vitamin A and the "browning" of the white fat were blunted: "As a consequence, fat oxidation and heat production were perturbed so that the mice were no longer able to protect themselves against the cold," explains Kiefer. In contrast, the addition of vitamin A to human white fat cells led to the expression of brown fat cell characteristics, with increased metabolic activity and energy consumption.

"Our results show that vitamin A plays an important role in the function of adipose tissue and affects global energy metabolism. However, this is not an argument for consuming large amounts of vitamin A supplements if not prescribed, because it is critical that vitamin A is transported to the right cells at the right time," explains the MedUni Vienna researcher. "We have discovered a new mechanism by which vitamin A regulates lipid combustion and heat generation in cold conditions. This could help us to develop new therapeutic interventions that exploit this specific mechanism."

Read more at Science Daily

Humans are born with brains 'prewired' to see words

 Humans are born with a part of the brain that is prewired to be receptive to seeing words and letters, setting the stage at birth for people to learn how to read, a new study suggests.

Analyzing brain scans of newborns, researchers found that this part of the brain -- called the "visual word form area" (VWFA) -- is connected to the language network of the brain.

"That makes it fertile ground to develop a sensitivity to visual words -- even before any exposure to language," said Zeynep Saygin, senior author of the study and assistant professor of psychology at The Ohio State University.

The VWFA is specialized for reading only in literate individuals. Some researchers had hypothesized that the pre-reading VWFA starts out being no different than other parts of the visual cortex that are sensitive to seeing faces, scenes or other objects, and only becomes selective to words and letters as children learn to read or at least as they learn language.

"We found that isn't true. Even at birth, the VWFA is more connected functionally to the language network of the brain than it is to other areas," Saygin said. "It is an incredibly exciting finding."

Saygin, who is a core faculty member of Ohio State's Chronic Brain Injury Program, conducted the study with graduate students Jin Li and Heather Hansen and assistant professor David Osher, all in psychology at Ohio State. Their results were published today in the journal Scientific Reports.

The researchers analyzed fMRI scans of the brains of 40 newborns, all less than a week old, who were part of the Developing Human Connectome Project. They compared these to similar scans from 40 adults who participated in the separate Human Connectome Project.

The VWFA is next to another part of visual cortex that processes faces, and it was reasonable to believe that there wasn't any difference in these parts of the brain in newborns, Saygin said.

As visual objects, faces have some of the same properties as words do, such as needing high spatial resolution for humans to see them correctly.

But the researchers found that, even in newborns, the VWFA was different from the part of the visual cortex that recognizes faces, primarily because of its functional connection to the language processing part of the brain.

"The VWFA is specialized to see words even before we're exposed to them," Saygin said.

"It's interesting to think about how and why our brains develop functional modules that are sensitive to specific things like faces, objects, and words," said Li, who is lead author of the study.

"Our study really emphasized the role of already having brain connections at birth to help develop functional specialization, even for an experience-dependent category like reading."

The study did find some differences in the VWFA in newborns and adults.

"Our findings suggest that there likely needs to be further refinement in the VWFA as babies mature," Saygin said.

"Experience with spoken and written language will likely strengthen connections with specific aspects of the language circuit and further differentiate this region's function from its neighbors as a person gains literacy."

Saygin's lab at Ohio State is currently scanning the brains of 3- and 4-year-olds to learn more about what the VWFA does before children learn to read and what visual properties the region is responsive to.

The goal is to learn how the brain becomes a reading brain, she said. Learning more about individual variability may help researchers understand differences in reading behavior and could be useful in the study of dyslexia and other developmental disorders.

Read more at Science Daily

ALMA shows volcanic impact on Io's atmosphere

 

Illustration of moon Io, with Jupiter in background

New radio images from the Atacama Large Millimeter/submillimeter Array (ALMA) show for the first time the direct effect of volcanic activity on the atmosphere of Jupiter's moon Io.

Io is the most volcanically active moon in our solar system. It hosts more than 400 active volcanoes, spewing out sulfur gases that give Io its yellow-white-orange-red colors when they freeze out on its surface.

Although it is extremely thin -- about a billion times thinner than Earth's atmosphere -- Io has an atmosphere that can teach us about Io's volcanic activity and provide us a window into the exotic moon's interior and what is happening below its colorful crust.

Previous research has shown that Io's atmosphere is dominated by sulfur dioxide gas, ultimately sourced from volcanic activity. "However, it is not known which process drives the dynamics in Io's atmosphere," said Imke de Pater of the University of California, Berkeley. "Is it volcanic activity, or gas that has sublimated (transitioned from solid to gaseous state) from the icy surface when Io is in sunlight?"

To distinguish between the different processes that give rise to Io's atmosphere, a team of astronomers used ALMA to make snapshots of the moon when it passed in and out of Jupiter's shadow (they call this an "eclipse").

"When Io passes into Jupiter's shadow, and is out of direct sunlight, it is too cold for sulfur dioxide gas, and it condenses onto Io's surface. During that time we can only see volcanically-sourced sulfur dioxide. We can therefore see exactly how much of the atmosphere is impacted by volcanic activity," explained Statia Luszcz-Cook from Columbia University, New York.

Thanks to ALMA's exquisite resolution and sensitivity, the astronomers could, for the first time, clearly see the plumes of sulfur dioxide (SO2) and sulfur monoxide (SO) rise up from the volcanoes. Based on the snapshots, they calculated that active volcanoes directly produce 30-50 percent of Io's atmosphere.

The ALMA images also showed a third gas coming out of volcanoes: potassium chloride (KCl). "We see KCl in volcanic regions where we do not see SO2 or SO," said Luszcz-Cook. "This is strong evidence that the magma reservoirs are different under different volcanoes."

Io is volcanically active due to a process called tidal heating. Io orbits Jupiter in an orbit that is not quite circular and, like our Moon always faces the same side of Earth, so does the same side of Io always face Jupiter. The gravitational pull of Jupiter's other moons Europa and Ganymede causes tremendous amounts of internal friction and heat, giving rise to volcanoes such as Loki Patera, which spans more than 200 kilometers (124 miles) across. "By studying Io's atmosphere and volcanic activity we learn more about not only the volcanoes themselves, but also the tidal heating process and Io's interior," added Luszcz-Cook.

A big unknown remains the temperature in Io's lower atmosphere. In future research, the astronomers hope to measure this with ALMA. "To measure the temperature of Io's atmosphere, we need to obtain a higher resolution in our observations, which requires that we observe the moon for a longer period of time. We can only do this when Io is in sunlight since it does not spend much time in eclipse," said de Pater. "During such an observation, Io will rotate by tens of degrees. We will need to apply software that helps us make un-smeared images. We have done this previously with radio images of Jupiter made with ALMA and the Very Large Array (VLA)."

Read more at Science Daily

This beetle can survive getting run over by a car. Engineers are figuring out how

 Getting run over by a car is not a near-death experience for the diabolical ironclad beetle.

How the beetle survives could inspire the development of new materials with the same herculean toughness, engineers show in a paper published Wednesday (Oct. 21) in Nature.

These materials would be stiff but ductile like a paper clip, making machinery such as aircraft gas turbines safer and longer-lasting, the researchers said.

The study, led by engineers at the University of California, Irvine (UCI) and Purdue University, found that the diabolical ironclad beetle's super-toughness lies in its two armorlike "elytron" that meet at a line, called a suture, running the length of the abdomen.

In flying beetles, the elytra protect wings and facilitate flight. But the diabolical ironclad beetle doesn't have wings. Instead, the elytra and connective suture help to distribute an applied force more evenly throughout its body.

"The suture kind of acts like a jigsaw puzzle. It connects various exoskeletal blades -- puzzle pieces -- in the abdomen under the elytra," said Pablo Zavattieri, Purdue's Jerry M. and Lynda T. Engelhardt Professor of Civil Engineering.

This jigsaw puzzle comes to the rescue in several different ways depending on the amount of force applied, Zavattieri said. A video explaining these findings is available on YouTube at https://youtu.be/NS3AqJB5SfU.

To uncover these strategies, a team led by UCI professor David Kisailus first tested the limits of the beetle's exoskeleton and characterized the various structural components involved by looking at CT scans.

Using compressive steel plates, UCI researchers found that the diabolical ironclad beetle can take on an applied force of about 150 newtons -- a load of at least 39,000 times its body weight -- before the exoskeleton begins to fracture.

That's more impressive than sounds: A car tire would apply a force of about 100 newtons if running over the beetle on a dirt surface, the researchers estimate. Other terrestrial beetles the team tested couldn't handle even half the force that a diabolical ironclad can withstand.

Zavattieri's lab followed up these experiments with extensive computer simulations and 3D-printed models that isolated certain structures to better understand their role in saving the beetle's life.

All of these studies combined revealed that when under a compressive load such as a car tire, the diabolical ironclad beetle's jigsaw-like suture offers two lines of defense.

First, the interconnecting blades lock to prevent themselves from pulling out of the suture like puzzle pieces. Second, the suture and blades delaminate, which leads to a more graceful deformation that mitigates catastrophic failure of the exoskeleton. Each strategy dissipates energy to circumvent a fatal impact at the neck, where the beetle's exoskeleton is most likely to fracture.

Even if a maximum force is applied to the beetle's exoskeleton, delamination allows the interconnecting blades to pull out from the suture more gently. If the blades were to interlock too much or too little, the sudden release of energy would cause the beetle's neck to snap.

It's not yet known if the diabolical ironclad beetle has a way to heal itself after surviving a car "accident." But knowing about these strategies could already solve fatigue problems in various kinds of machinery.

"An active engineering challenge is joining together different materials without limiting their ability to support loads. The diabolical ironclad beetle has strategies to circumvent these limitations," said David Restrepo, an assistant professor at the University of Texas at San Antonio who worked on this project as a postdoctoral researcher in Zavattieri's group.

In the gas turbines of aircraft, for example, metals and composite materials are joined together with a mechanical fastener. This fastener adds weight and introduces stress that could lead to fractures and corrosion.

"These fasteners ultimately decrease the performance of the system and need to be replaced every so often. But the interfacial sutures of the diabolical ironclad beetle provide a robust and more predictable failure that could help solve these problems," said Maryam Hosseini, who worked on this project as a Ph.D. student and postdoctoral researcher in Zavattieri's group. Hosseini is now an engineering manager at Procter & Gamble Corp.

UCI researchers built a carbon fiber composite fastener mimicking a diabolical ironclad beetle's suture. Purdue researchers found through loading tests that this fastener is just as strong as a standard aerospace fastener, but significantly tougher.

"This work shows that we may be able to shift from using strong, brittle materials to ones that can be both strong and tough by dissipating energy as they break. That's what nature has enabled the diabolical ironclad beetle to do," Zavattieri said.

Read more at Science Daily

High flavanol diet may lead to lower blood pressure

 People who consume a diet including flavanol-rich foods and drinks, including tea, apples and berries, could lead to lower blood pressure, according to the first study using objective measures of thousands of UK residents' diet.

The findings, published in Scientific Reports, studied the diet of more than 25,000 people in Norfolk, UK and compared what they ate with their blood pressure. In contrast to most other studies investigating links between nutrition and health, the researchers did not rely on study participants reporting their diet, but instead measured flavanol intake objectively using nutritional biomarkers -- indicators of dietary intake, metabolism or nutritional status that are present in our blood.

The difference in blood pressure between those with the lowest 10% of flavanol intake and those with the highest 10% of intake was between 2 and 4 mmHg. This is comparable to meaningful changes in blood pressure observed in those following a Mediterranean diet or Dietary Approaches to Stop Hypertension (DASH) diet. Notably, the effect was more pronounced in participants with hypertension.

Professor Gunter Kuhnle, a nutritionist at the University of Reading who led the study said:

"Previous studies of large populations have always relied on self-reported data to draw conclusions, but this is the first epidemiological study of this scale to objectively investigate the association between a specific bioactive compound and health. We are delighted to see that in our study, there was also a meaningful and significant association between flavanol consumption and lower blood pressure.

"What this study gives us is an objective finding about the association between flavanols -- found in tea and some fruits -- and blood pressure. This research confirms the results from previous dietary intervention studies and shows that the same results can be achieved with a habitual diet rich in flavanols. In the British diet, the main sources are tea, cocoa, apples and berries.

"The methodology of the study is of equal importance. This is one of the largest ever studies to use nutritional biomarkers to investigate bioactive compounds. Using nutritional biomarkers to estimate intake of bioactive food compounds has long been seen as the gold standard for research, as it allows intake to be measured objectively. The development, validation and application of the biomarker was only possible because of the long-term commitment of all collaborators. In contrast to self-reported dietary data, nutritional biomarkers can address the huge variability in food composition. We can therefore confidently attribute the associations we observed to flavanol intake."

An international team from the University of Reading, Cambridge University, the University of California Davis, and Mars, Incorporated studied 25,618 participants from the European Prospective Investigation into Cancer (EPIC) Norfolk study and found that the biggest difference was observed in participants with the highest blood pressure. This suggests if the general public increased its flavanol intake, there could be an overall reduction in cardiovascular disease incidence.

Hagen Schroeter, Chief Science Officer at Mars Edge, said:

"This study adds key insights to a growing body of evidence supporting the benefits of dietary flavanols in health and nutrition. But, perhaps even more exciting was the opportunity to apply objective biomarkers of flavanol intake at a large scale. This enabled the team to avoid the significant limitations that come with past approaches which rely on estimating intake based on self-reported food consumption data and the shortcomings of current food composition databases."

Read more at Science Daily

Seeing no longer believing: the manipulation of online images

 A peace sign from Martin Luther King, Jr, becomes a rude gesture; President Donald Trump's inauguration crowd scenes inflated; dolphins in Venice's Grand Canal; and crocodiles on the streets of flooded Townsville -- all manipulated images posted as truth.

Image editing software is so ubiquitous and easy to use, according to researchers from QUT's Digital Media Research Centre, it has the power to re-imagine history.

And, they say, deadline-driven journalists lack the tools to tell the difference, especially when the images come through from social media.

Their study, Visual mis/disinformation in journalism and public communications, has been published in Journalism Practice. It was driven by the increased prevalence of fake news and how social media platforms and news organisations are struggling to identify and combat visual mis/disinformation presented to their audiences.

"When Donald Trump's staff posted an image to his official Facebook page in 2019, journalists were able to spot the photoshopped edits to the president's skin and physique because an unedited version exists on the White House's official Flickr feed," said lead author Dr T.J. Thomson.

"But what about when unedited versions aren't available online and journalists can't rely on simple reverse-image searches to verify whether an image is real or has been manipulated?

"When it is possible to alter past and present images, by methods like cloning, splicing, cropping, re-touching or re-sampling, we face the danger of a re-written history -- a very Orwellian scenario."

Examples highlighted in the report include photos shared by news outlets last year of crocodiles on Townsville streets during a flood which were later shown to be images of alligators in Florida from 2014. It also quotes a Reuters employee on their discovery that a harrowing video shared during Cyclone Idai, which devastated parts of Africa in 2019, had been shot in Libya five years earlier.

An image of Dr Martin Luther King Jr's reaction to the US Senate's passing of the civil rights bill in 1964, was manipulated to make it appear that he was flipping the bird to the camera. This edited version was shared widely on Twitter, Reddit, and white supremacist website The Daily Stormer.

Dr Thomson, Associate Professor Daniel Angus, Dr Paula Dootson, Dr Edward Hurcombe, and Adam Smith have mapped journalists' current social media verification techniques and suggest which tools are most effective for which circumstances.

"Detection of false images is made harder by the number of visuals created daily -- in excess of 3.2 billion photos and 720,000 hours of video -- along with the speed at which they are produced, published, and shared," said Dr Thomson.

"Other considerations include the digital and visual literacy of those who see them. Yet being able to detect fraudulent edits masquerading as reality is critically important.

"While journalists who create visual media are not immune to ethical breaches, the practice of incorporating more user-generated and crowd-sourced visual content into news reports is growing. Verification on social media will have to increase commensurately if we wish to improve trust in institutions and strengthen our democracy."

Dr Thomson said a recent quantitative study performed by the International Centre for Journalists (ICFJ) found a very low usage of social media verification tools in newsrooms.

"The ICFJ surveyed over 2,700 journalists and newsroom managers in more than 130 countries and found only 11% of those surveyed used social media verification tools," he said.

"The lack of user-friendly forensic tools available and low levels of digital media literacy, combined, are chief barriers to those seeking to stem the tide of visual mis/disinformation online."

Associate Professor Angus said the study demonstrated an urgent need for better tools, developed with journalists, to provide greater clarity around the provenance and authenticity of images and other media.

"Despite knowing little about the provenance and veracity of the visual content they encounter, journalists have to quickly determine whether to re-publish or amplify this content," he said.

"The many examples of misattributed, doctored, and faked imagery attest to the importance of accuracy, transparency, and trust in the arena of public discourse. People generally vote and make decisions based on information they receive via friends and family, politicians, organisations, and journalists."

Read more at Science Daily

NASA's OSIRIS-REx spacecraft successfully touches asteroid

 

NASA's OSIRIS-REx mission readies itself to touch the surface of asteroid Bennu.

NASA's Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft unfurled its robotic arm Tuesday, and in a first for the agency, briefly touched an asteroid to collect dust and pebbles from the surface for delivery to Earth in 2023.

This well-preserved, ancient asteroid, known as Bennu, is currently more than 200 million miles (321 million kilometers) from Earth. Bennu offers scientists a window into the early solar system as it was first taking shape billions of years ago and flinging ingredients that could have helped seed life on Earth. If Tuesday's sample collection event, known as "Touch-And-Go" (TAG), provided enough of a sample, mission teams will command the spacecraft to begin stowing the precious primordial cargo to begin its journey back to Earth in March 2021. Otherwise, they will prepare for another attempt in January.

"This amazing first for NASA demonstrates how an incredible team from across the country came together and persevered through incredible challenges to expand the boundaries of knowledge," said NASA Administrator Jim Bridenstine. "Our industry, academic, and international partners have made it possible to hold a piece of the most ancient solar system in our hands."

At 1:50 p.m. EDT, OSIRIS-REx fired its thrusters to nudge itself out of orbit around Bennu. It extended the shoulder, then elbow, then wrist of its 11-foot (3.35-meter) sampling arm, known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), and transited across Bennu while descending about a half-mile (805 meters) toward the surface. After a four-hour descent, at an altitude of approximately 410 feet (125 meters), the spacecraft executed the "Checkpoint" burn, the first of two maneuvers to allow it to precisely target the sample collection site, known as "Nightingale."

Ten minutes later, the spacecraft fired its thrusters for the second "Matchpoint" burn to slow its descent and match the asteroid's rotation at the time of contact. It then continued a treacherous, 11-minute coast past a boulder the size of a two-story building, nicknamed "Mount Doom," to touch down in a clear spot in a crater on Bennu's northern hemisphere. The size of a small parking lot, the site Nightingale site is one of the few relatively clear spots on this unexpectedly boulder-covered space rock.

"This was an incredible feat -- and today we've advanced both science and engineering and our prospects for future missions to study these mysterious ancient storytellers of the solar system," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate at the agency's headquarters in Washington. "A piece of primordial rock that has witnessed our solar system's entire history may now be ready to come home for generations of scientific discovery, and we can't wait to see what comes next."

"After over a decade of planning, the team is overjoyed at the success of today's sampling attempt," said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. "Even though we have some work ahead of us to determine the outcome of the event -- the successful contact, the TAGSAM gas firing, and back-away from Bennu are major accomplishments for the team. I look forward to analyzing the data to determine the mass of sample collected."

All spacecraft telemetry data indicates the TAG event executed as expected. However, it will take about a week for the OSIRIS-REx team to confirm how much sample the spacecraft collected.

Real-time data indicates the TAGSAM successfully contacted the surface and fired a burst of nitrogen gas. The gas should have stirred up dust and pebbles on Bennu's surface, some of which should have been captured in the TAGSAM sample collection head. OSIRIS-REx engineers also confirmed that shortly after the spacecraft made contact with the surface, it fired its thrusters and safely backed away from Bennu.

"Today's TAG maneuver was historic," said Lori Glaze, Planetary Science Division director at NASA Headquarters in Washington. "The fact that we safely and successfully touched the surface of Bennu, in addition to all the other milestones this mission has already achieved, is a testament to the living spirit of exploration that continues to uncover the secrets of the solar system."

"It's hard to put into words how exciting it was to receive confirmation that the spacecraft successfully touched the surface and fired one of the gas bottles," said Michael Moreau, OSIRIS-REx deputy project manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The team can't wait to receive the imagery from the TAG event late tonight and see how the surface of Bennu responded to the TAG event."

The spacecraft carried out TAG autonomously, with pre-programmed instructions from engineers on Earth. Now, the OSIRIS-REx team will begin to assess whether the spacecraft grabbed any material, and, if so, how much; the goal is at least 60 grams, which is roughly equivalent to a full-size candy bar.

OSIRIS-REx engineers and scientists will use several techniques to identify and measure the sample remotely. First, they'll compare images of the Nightingale site before and after TAG to see how much surface material moved around in response to the burst of gas.

"Our first indication of whether we were successful in collecting a sample will come on October 21 when we downlink the back-away movie from the spacecraft," Moreau said. "If TAG made a significant disturbance of the surface, we likely collected a lot of material."

Next, the team will try to determine the amount of sample collected. One method involves taking pictures of the TAGSAM head with a camera known as SamCam, which is devoted to documenting the sample-collection process and determining whether dust and rocks made it into the collector head. One indirect indication will be the amount of dust found around the sample collector head. OSIRIS-REx engineers also will attempt to snap photos that could, given the right lighting conditions, show the inside of the head so engineers can look for evidence of sample inside of it.

A couple of days after the SamCam images are analyzed, the spacecraft will attempt yet another method to measure the mass of the sample collected by determining the change in the spacecraft's "moment of inertia," a phrase that describes how mass is distributed and how it affects the rotation of the body around a central axis. This maneuver entails extending the TAGSAM arm out to the side of the spacecraft and slowly spinning the spacecraft about an axis perpendicular to the arm. This technique is analogous to a person spinning with one arm extended while holding a string with a ball attached to the end. The person can sense the mass of the ball by the tension in the string. Having performed this maneuver before TAG, and now after, engineers can measure the change in the mass of the collection head as a result of the sample inside.

"We will use the combination of data from TAG and the post-TAG images and mass measurement to assess our confidence that we have collected at least 60 grams of sample," said Rich Burns, OSIRIS-REx project manager at Goddard. "If our confidence is high, we'll make the decision to stow the sample on October 30."

To store the sample, engineers will command the robotic arm to place the sample collector head into the Sample Return Capsule (SRC), located in the body of the spacecraft. The sample arm will then retract to the side of the spacecraft for the final time, the SRC will close, and the spacecraft will prepare for its departure from Bennu in March 2021 -- this is the next time Bennu will be properly aligned with Earth for the most fuel-efficient return flight.

If, however, it turns out that the spacecraft did not collect enough sample at Nightingale, it will attempt another TAG maneuver on Jan. 12, 2021. If that occurs, it will touch down at the backup site called "Osprey," which is another relatively boulder-free area inside a crater near Bennu's equator.

OSIRIS-REx launched from Cape Canaveral Air Force Station in Florida Sept. 8, 2016. It arrived at Bennu Dec. 3, 2018, and began orbiting the asteroid for the first time on Dec. 31, 2018. The spacecraft is scheduled to return to Earth Sept. 24, 2023, when it will parachute the SRC into Utah's west desert where scientists will be waiting to collect it.

Read more at Science Daily

Ultraviolet shines light on origins of the solar system

 By analyzing the oxygen isotopes (varieties of an element that have some extra neutrons) of these refractory inclusions, the research team has determined that the differences in composition between the sun, planets and other solar system materials were inherited from the protosolar molecular cloud that existed even before the solar system. The results of their study have been recently published in Science Advances.

"It has been recently demonstrated that variations in isotopic compositions of many elements in our solar system were inherited from the protosolar molecular cloud," said lead author Alexander Krot, of the University of Hawaii. "Our study reveals that oxygen is not the exception."

Molecular cloud or solar nebula?

When scientists compare oxygen isotopes 16, 17 and 18, they observe significant differences between the Earth and the sun. This is believed to be due to processing by ultraviolet light of carbon monoxide, which is broken apart leading to a large change in oxygen isotope ratios in water. The planets are formed from dust that inherits the changed oxygen isotope ratios through interactions with water.

What scientists have not known is whether the ultraviolet processing occurred in the parent molecular cloud that collapsed to form the proto-solar system or later in the cloud of gas and dust from which the planets formed, called the solar nebula.

To determine this, the research team turned to the most ancient component of meteorites, called calcium-aluminum inclusions (CAIs). They used an ion microprobe, electron backscatter images and X-ray elemental analyses at the University of Hawaii's Institute of Geophysics and Planetology to carefully analyze the CAIs. They then incorporated a second isotope system (aluminum and magnesium isotopes) to constrain the age of the CAIs, making the connection -- for the first time -- between oxygen isotope abundances and mass 26 aluminum isotopes.

From these aluminum and magnesium isotopes, they concluded that the CAIs were formed about 10,000 to 20,000 years after the collapse of the parent molecular cloud.

"This is extremely early in the history of the solar system," said Lyons, who is an associate research professor at ASU's School of Earth and Space Exploration, "so early that there would not be enough time to alter oxygen isotopes in the solar nebula."

Although more measurements and modeling work are needed to fully assess the implications of these findings, they do have implications for the inventory of organic compounds available during solar system and later planet and asteroid formation.

Read more at Science Daily

CRISPR meets Pac-Man: New DNA cut-and-paste tool enables bigger gene edits

 Gene editing for the development of new treatments, and for studying disease as well as normal function in humans and other organisms, may advance more quickly with a new tool for cutting larger pieces of DNA out of a cell's genome, according to a new study by UC San Francisco scientists.

Publication of the UCSF study on Oct. 19, 2020 in the journal Nature Methods comes less than two weeks after two researchers who first used the genetic scissors known as CRISPR-Cas9 were selected to receive this year's Nobel Prize in Chemistry.

Though now employed as a research tool in laboratories around the world, CRISPR evolved eons ago in bacteria as a means to fight their ancient nemeses, a whole host of viruses known as bacteriophages. When bacteria encounter a phage, they incorporate a bit of the viral DNA into their own DNA, and it then serves as a template to make RNA that binds to the corresponding viral DNA in the phage itself. The CRISPR enzymes then target, disable and kill the phage.

In his latest work exploring this ancient and strange arms race, principal investigator Joseph Bondy-Denomy, PhD, associate professor in the UCSF Department of Microbiology and Immunology, joined scientists Bálint Csörg?, PhD, and Lina León to develop and test a new CRISPR tool.

The already renowned CRISPR-Cas9 ensemble is like a molecular chisel that can be used to rapidly and precisely excise a small bit of DNA at a targeted site. Other methods can then be used to insert new DNA. But the new CRISPR-Cas3 system adapted by the UCSF scientists employs a different bacterial immune system. The key enzyme in this system, Cas3, acts more like a molecular wood chipper to remove much longer stretches of DNA quickly and accurately.

"Cas3 is like Cas9 with a motor -- after finding its specific DNA target, it runs on DNA and chews it up like a Pac-Man," Bondy-Denomy said.

This new capability to delete or replace long stretches of DNA will enable researchers to more efficiently assess the importance of genomic regions that contain DNA sequences of indeterminate function, according to Bondy-Denomy, an important consideration in understanding humans and the pathogens that plague them.

"Previously, there was no easy and reliable way to delete very large regions of DNA in bacteria for research or therapeutic purposes," he said. "Now, instead of making 100 different small DNA deletions we can just make one deletion and ask, 'What changed?'"

Because bacteria and other types of cells are commonly used to produce small molecule or protein-based pharmaceuticals, CRISPR-Cas3 will enable biotechnology industry scientists to more easily remove potentially pathogenic or useless DNA from these cells, according to Bondy-Denomy.

"Large swathes of bacterial DNA are poorly understood, with unknown functions that in some cases are not necessary for survival," Bondy-Denomy said. "In addition, bacterial DNA contains large stretches of DNA imported from other sources, which can cause disease in the bacterium's human host, or divert bacterial metabolism."

CRISPR-Cas3 also should also allow entire genes to be inserted into the genome in industrial, agricultural or even in human gene therapy applications, Bondy-Denomy said.

The UCSF researchers selected and modified the CRISPR-Cas3 system used by the bacterium Pseudomonas aeruginosa, and demonstrated in this species and in three others, including bacteria that cause disease in humans and plants, that their more compact version functions well to remove selected DNA in all four species. Other CRISPR-Cas3 systems have been made to work in human and other mammalian cells, and that also should be achievable for the modified P. aeruginosa system, Bondy-Denomy said.

Bondy-Denomy studies a range of bacteria, bacteriophage, and CRISPR systems to learn more about how they work and to find useful molecular tools. "CRISPR-Cas3 is by far the most common CRISPR system in nature," he said. "About 10 times as many bacterial species use a Cas3 system as use a Cas9 system. It may be that Cas3 is a better bacterial immune system because it shreds phage DNA."

Unlike Cas9, when Cas3 binds to its precise DNA target it begins chewing up one strand of the double-stranded DNA in both directions, leaving a single strand exposed. The deletions obtained in the UCSF experiments ranged in size, in many cases encompassing as many as 100 bacterial genes. The CRISPR-Cas3 mechanism should also allow for easier replacement of deleted DNA with a new DNA sequence, the researchers found.

For DNA deletion and editing in the lab, scientists program CRISPR systems to target specific DNA in the genome of an organism of interest using any guide sequence they choose.

In the new CRISPR-Cas3 study, by manipulating the sequences of DNA provided to the bacteria for repairing the deletions, the researchers were able to precisely set the boundaries of these large DNA repairs, something they were unable to accomplish with CRISPR-Cas9.

Read more at Science Daily

Study shows active older adults have better physical and mental health

 Older adults with higher physical activity and lower sitting time have better overall physical and mental health, according to a new study from the American Cancer Society (ACS). The study, appearing in the journal, CANCER, suggests that higher amounts of regular moderate- to vigorous-intensity physical activity (MVPA) and lower duration of sedentary time is associated with higher global mental and physical health for older cancer survivors and older adults, in general.

With a rapidly aging population and nearly 16.9 million cancer survivors in the United States today, there is a need to identify strategies associated with healthy aging and improving quality of life for aging cancer survivors. Being physically active is related to several health benefits, and in this study, ACS investigators led by Dr. Erika Rees-Punia analyzed self-reported aerobic and muscle-strengthening physical activities, sitting time, and mental and physical health among nearly 78,000 participants in the ACS's Cancer Prevention Study II Nutrition Cohort. Participants (average age 78 years) included older cancer survivors up to 10 years post-diagnosis, and cancer-free adults.

The investigators found that regardless of cancer history, the differences in global mental and physical health between the most and least active, and the least and most sedentary, were clinically meaningful. These findings provide evidence for the importance of engaging in regular MVPA and decreasing sitting time as a reasonable non-pharmacologic strategy to improve quality of life in older men and women, with or without a prior cancer diagnosis. In fact, the recently published ACS physical activity guidelines recommend that adults get 150-300 minutes of moderate-intensity activity or 75-150 minutes of vigorous-intensity activity through the week, and to limit sedentary behaviors such as screen-based entertainment.

"The findings reinforce the importance of moving more and sitting less for both physical and mental health, no matter your age or history of cancer," said Rees-Punia. "This is especially relevant now as so many of us, particularly cancer survivors, may be staying home to avoid COVID-19 exposure, and may be feeling a little isolated or down. A simple walk or other physical activity that you enjoy may be good for your mind and body."

From Science Daily

Targeting the shell of the Ebola virus

 As the world grapples with the coronavirus (COVID-19) pandemic, another virus has been raging again in the Democratic Republic of the Congo in recent months: Ebola. Since the first terrifying outbreak in 2013, the Ebola virus has periodically emerged in Africa, causing horrific bleeding in its victims and, in many cases, death.

How can we battle these infectious agents that reproduce by hijacking cells and reprogramming them into virus-replicating machines? Science at the molecular level is critical to gaining the upper hand -- research you'll find underway in the laboratory of Professor Juan Perilla at the University of Delaware.

Perilla and his team of graduate and undergraduate students in UD's Department of Chemistry and Biochemistry are using supercomputers to simulate the inner workings of Ebola, observing the way molecules move, atom by atom, to carry out their functions. In the team's latest work, they reveal structural features of the virus's coiled protein shell, or nucleocapsid, that may be promising therapeutic targets, more easily destabilized and knocked out by an antiviral treatment.

The research is highlighted in the Tuesday, Oct. 20 issue of the Journal of Chemical Physics, which is published by the American Institute of Physics, a federation of societies in the physical sciences representing more than 120,000 members.

"The Ebola nucleocapsid looks like a Slinky walking spring, whose neighboring rings are connected," Perilla said. "We tried to find what factors control the stability of this spring in our computer simulations."

The life cycle of Ebola is highly dependent on this coiled nucleocapsid, which surrounds the virus's genetic material consisting of a single strand of ribonucleic acid (ssRNA). Nucleoproteins protect this RNA from being recognized by cellular defense mechanisms. Through interactions with different viral proteins, such as VP24 and VP30, these nucleoproteins form a minimal functional unit -- a copy machine -- for viral transcription and replication.

While nucleoproteins are important to the nucleocapsid's stability, the team's most surprising finding, Perilla said, is that in the absence of single-stranded RNA, the nucleocapsid quickly becomes disordered. But RNA alone is not sufficient to stabilize it. The team also observed charged ions binding to the nucleocapsid, which may reveal where other important cellular factors bind and stabilize the structure during the virus's life cycle.

Perilla compared the team's work to a search for molecular "knobs" that control the nucleocapsid's stability like volume control knobs that can be turned up to hinder virus replication.

The UD team built two molecular dynamics systems of the Ebola nucleocapsid for their study. One included single-stranded RNA; the other contained only the nucleoprotein. The systems were then simulated using the Texas Advanced Computing Center's Frontera supercomputer -- the largest academic supercomputer in the world. The simulations took about two months to complete.

Graduate research assistant Chaoyi Xu ran the molecular simulations, while the entire team was involved in developing the analytical framework and conducting the analysis. Writing the manuscript was a learning experience for Xu and undergraduate research assistant Tanya Nesterova, who had not been directly involved in this work before. She also received training as a next-generation computational scientist with support from UD's Undergraduate Research Scholars program and NSF's XSEDE-EMPOWER program. The latter has allowed her to perform the highest-level research using the nation's top supercomputers. Postdoctoral researcher Nidhi Katyal's expertise also was essential to bringing the project to completion, Perilla said.

While a vaccine exists for Ebola, it must be kept extremely cold, which is difficult in remote African regions where outbreaks have occurred. Will the team's work help advance new treatments?

"As basic scientists we are excited to understand the fundamental principles of Ebola," Perilla said. "The nucleocapsid is the most abundant protein in the virus and it's highly immunogenic -- able to produce an immune response. Thus, our new findings may facilitate the development of new antiviral treatments."

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Prebiotic chemistry: In the beginning, there was sugar

 Organic molecules formed the basis for the evolution of life. But how could inorganic precursors have given rise to them? Ludwig-Maximilians-Universitaet (LMU) in Munich chemist Oliver Trapp now reports a reaction pathway in which minerals catalyze the formation of sugars in the absence of water.

More than 4 billion years ago, the Earth was very far from being the Blue Planet it would later become. At that point it had just begun to cool and, in the course of that process, the concentric structural zones that lie ever deeper beneath our feet were formed. The early Earth was dominated by volcanism, and the atmosphere was made up of carbon dioxide, nitrogen, methane, ammonia, hydrogen sulfide and water vapor. In this decidedly inhospitable environment the building blocks of life were formed. How then might this have come about?

Researchers have puzzled over the question for decades. The first breakthrough was made in 1953 by two chemists, named Stanley Miller and Harold C. Urey, at the University of Chicago. In their experiments, they simulated the atmosphere of the primordial Earth in a closed reaction system that contained the gases mentioned above. A miniature 'ocean' was heated to provide water vapor, and electrical discharges were passed through the system to mimic the effects of lightning. When they analyzed the chemicals produced under these conditions, Miller and Urey detected amino acids -- the basic constituents of proteins -- as well as a number of other organic acids.

It is now known that the conditions employed in these experiments did not reflect those that prevailed on the early Earth. Nevertheless, the Miller-Urey experiment initiated the field of prebiotic chemical evolution. However, it not throw much light on how other classes of molecules found in all biological cells -- such as sugars, fats and nucleic acids -- might have been generated. These compounds are however indispensable ingredients of the process that led to the first bacteria and subsequently to photosynthetic cyanobacteria that produced oxygen. This is why Oliver Trapp, Professor of Organic Chemistry at LMU, decided to focus his research on the prebiotic synthesis of these substances.

From formaldehyde to sugar

The story of synthetic routes from smaller precursors to sugars goes back almost a century prior to the Miller-Urey experiment. In 1861, the Russian chemist Alexander Butlerov showed that formaldehyde could give rise to various sugars via what became known as the formose reaction. Miller und Urey in fact found formic acid in their experiments, and it can be readily reduced to yield formaldehyde. Butlerov also discovered that the formose reaction is promoted by a number of metal oxides and hydroxides, including those of calcium, barium, thallium and lead. Notably calcium is abundantly available on and below the Earth's surface.

However, the hypothesis that sugars could have been produced via the formose reaction runs into two difficulties. The 'classical' formose reaction produces a diverse mixture of compounds, and it takes place only in aqueous media. These requirements are at odds with the fact that sugars have been detected in meteorites.

Together with colleagues at LMU and the Max Planck Institute for Astronomy in Heidelberg, Trapp therefore decided to explore whether formaldehyde could give rise to sugars in a solid-phase system. With a view to simulating the kinds of mechanical forces to which solid minerals would have been subjected, all the reaction components were combined in a ball mill -- in the absence of solvents, but adding enough formaldehyde to saturate the powdered solids

And indeed, the formose reaction was observed and several different minerals were found to catalyze it. The formaldehyde was adsorbed onto the solid particles, and the interaction resulted in the formation of the formaldehyde dimer (glycolaldehyde) -- and ribose, the 5-carbon sugar that is an essential constituent of ribonucleic acid (RNA). RNA is thought to have merged prior to DNA, and it serves as the repository of genetic information in many viruses, as well as providing the templates for protein synthesis in all cellular organisms. More complex sugars were also obtained in the experiments, together with a few byproducts, such as lactic acid and methanol.

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The Milky Way galaxy has a clumpy halo

 The Milky Way galaxy is in the recycling business.

University of Iowa astronomers have determined our galaxy is surrounded by a clumpy halo of hot gases that is continually being supplied with material ejected by birthing or dying stars. This heated halo, called the circumgalactic medium (CGM), was the incubator for the Milky Way's formation some 10 billion years ago and could be where basic matter unaccounted for since the birth of the universe may reside.

The findings come from observations made by HaloSat, one of a class of minisatellites designed and built at Iowa -- this one primed to look at the X-rays emitted by the CGM. The researchers conclude the CGM has a disk-like geometry, based on the intensity of X-ray emissions coming from it. The HaloSat minisatellite was launched from the International Space Station in May 2018 and is the first minisatellite funded by NASA's Astrophysics Division.

"Where the Milky Way is forming stars more vigorously, there are more X-ray emissions from the circumgalactic medium," says Philip Kaaret, professor in the Iowa Department of Physics and Astronomy and corresponding author on the study, published online in the journal Nature Astronomy. "That suggests the circumgalactic medium is related to star formation, and it is likely we are seeing gas that previously fell into the Milky Way, helped make stars, and now is being recycled into the circumgalactic medium."

Each galaxy has a CGM, and these regions are crucial to understanding not only how galaxies formed and evolved but also how the universe progressed from a kernel of helium and hydrogen to a cosmological expanse teeming with stars, planets, comets, and all other sorts of celestial constituents.

HaloSat was launched into space in 2018 to search for atomic remnants called baryonic matter believed to be missing since the universe's birth nearly 14 billion years ago. The satellite has been observing the Milky Way's CGM for evidence the leftover baryonic matter may reside there.

To do that, Kaaret and his team wanted to get a better handle on the CGM's configuration.

More specifically, the researchers wanted to find out if the CGM is a huge, extended halo that is many times the size of our galaxy -- in which case, it could house the total number of atoms to solve the missing baryon question. But if the CGM is mostly comprised of recycled material, it would be a relatively thin, puffy layer of gas and an unlikely host of the missing baryonic matter.

"What we've done is definitely show that there's a high-density part of the CGM that's bright in X-rays, that makes lots of X-ray emissions," Kaaret says. "But there still could be a really big, extended halo that is just dim in X-rays. And it might be harder to see that dim, extended halo because there's this bright emission disc in the way.

"So it turns out with HaloSat alone, we really can't say whether or not there really is this extended halo."

Kaaret says he was surprised by the CGM's clumpiness, expecting its geometry to be more uniform. The denser areas are regions where stars are forming, and where material is being traded between the Milky Way and the CGM.

"It seems as if the Milky Way and other galaxies are not closed systems," Kaaret says. "They're actually interacting, throwing material out to the CGM and bringing back material as well."

The next step is to combine the HaloSat data with data from other X-ray observatories to determine whether there's an extended halo surrounding the Milky Way, and if it's there, to calculate its size. That, in turn, could solve the missing baryon puzzle.

Read more at Science Daily

Paper recycling must be powered by renewables to save climate

 Recycling paper may only be helpful to the climate if it is powered by renewable energy, according to a new modelling study by researchers at UCL and Yale.

The study, published in Nature Sustainability, found that greenhouse gas emissions would increase by 2050 if we recycled more paper, as current methods rely on fossil fuels and electricity from the grid.

The researchers modelled various scenarios for increasing recycling of wastepaper by 2050 and the impact this would have on greenhouse emissions. They found that if all wastepaper was recycled, emissions could increase by 10%, as recycling paper tends to rely more on fossil fuels than making new paper.

However, the researchers found that emissions would radically reduce if paper production and disposal were carried out using renewable energy sources rather than fossil fuels.

Making new paper from trees requires more energy than paper recycling, but the energy for this process is generated from black liquor -- the low-carbon by-product of the wood pulping process. In contrast, paper recycling relies on fuels and electricity from the grid.

Researchers found that modernising landfill practices, for instance by capturing methane emissions and using them for energy, also had a positive effect -- although not as profound as moving to renewables.

Lead author Dr Stijn van Ewijk (UCL Institute for Sustainable Resources and Yale Center for Industrial Ecology) said: "Our study shows that recycling is not a guaranteed way to address climate change. Recycling of paper may not be helpful unless it is powered by renewable energy.

"We looked at global averages, but trends may vary considerably in different parts of the world. Our message isn't to stop recycling, but to point out the risk of investing in recycling at the expense of decarbonising the energy supply and seeing very little change to emissions as a result."

Senior author Professor Paul Ekins (UCL Institute for Sustainable Resources) said: "The recycling of some materials, for instance metals, can lead to a very large reduction in emissions. But we need to be careful about assumptions that recycling, or a circular economy in general, will always have a positive effect on climate change."

The researchers emphasized that recycling has benefits beyond combatting global warming. Co-author Professor Julia Stegemann (UCL Civil, Environmental & Geomatic Engineering) said: "Our exponentially increasing consumption of global resources has many seriously damaging environmental impacts beyond climate change, and conserving resources, including by paper recycling, remains critical for sustainability."

The researchers reported that paper accounted for 1.3% of global greenhouse gas emissions in 2012. About a third of these emissions came from the disposal of paper in landfills. Researchers said that in coming years, use of paper would likely rise, with the move away from plastics leading to increased demand for paper packaging.

The study looked at how different levels of recycling, renewable energy use and more environmentally friendly landfill practices might affect our ability to reduce emissions in line with a target to avoid a 2-degrees Celsius temperature rise by 2050.

It found that if past trends continued, emissions would slightly increase from the 2012 level (721 metric tonnes of carbon dioxide equivalent in a year) to 736 metric tonnes in 2050, with efforts to reduce emissions outweighed by increased demand for paper.

A radical programme of recycling, with landfill and energy uses remaining on the same path, would increase this still further by 10% (to 808 metric tonnes), with savings due to a decrease in total energy use outweighed by an increase in the use of high-carbon electricity.

On the other hand, radically modernising landfill practices would reduce emissions to 591 metric tonnes, while moving to renewables, with recycling and landfill practices remaining on the standard path, would reduce emissions by 96% to 28 tonnes.

Read more at Science Daily