Astronomers to release most accurate data ever for nearly two billion stars

 On 3 December an international team of astronomers will announce the most detailed ever catalogue of the stars in a huge swathe of our Milky Way galaxy. The measurements of stellar positions, movement, brightness and colours are in the third early data release from the European Space Agency's Gaia space observatory and will be publicly available. Initial findings include the first optical measurement of the acceleration of the Solar system. The data set, and early scientific discoveries, will be presented at a special briefing hosted by the Royal Astronomical Society.

Launched in 2013, Gaia operates in an orbit around the so-called Lagrange 2 (L2) point, located 1.5 million kilometres behind the Earth in the direction away from the Sun. At L2 the gravitational forces between the Earth and Sun are balanced, so the spacecraft stays in a stable position, allowing long-term essentially unobstructed views of the sky.

The primary objective of Gaia is measure stellar distances using the parallax method. In this case astronomers use the observatory to continuously scan the sky, measuring the apparent change in the positions of stars over time, resulting from the Earth's movement around the Sun.

Knowing that tiny shift in the positions of stars allows their distances to be calculated. On Earth this is made more difficult by the blurring of the Earth's atmosphere, but in space the measurements are only limited by the optics of the telescope.

Two previous releases included the positions of 1.6 billion stars. This release brings the total to just under 2 billion stars, whose positions are significantly more accurate than in the earlier data. Gaia also tracks the changing brightness and positions of the stars over time across the line of sight (their so-called proper motion), and by splitting their light into spectra, measures how fast they are moving towards or away from the Sun and assesses their chemical composition.

The new data include exceptionally accurate measurements of the 300,000 stars within the closest 326 light years to the Sun. The researchers use these data to predict how the star background will change in the next 1.6 million years. They also confirm that the Solar system is accelerating in its orbit around the Galaxy.

This acceleration is gentle, and is what would be expected from a system in a circular orbit. Over a year the Sun accelerates towards the centre of the Galaxy by 7 mm per second, compared with its speed along its orbit of about 230 kilometres a second.

Gaia data additionally deconstruct the two largest companion galaxies to the Milky Way, the Small and Large Magellanic Clouds, allowing researchers to see their different stellar populations. A dramatic visualisation shows these subsets, and the bridge of stars between the two systems.

Dr Floor van Leeuwen of the Institute of Astronomy at the University of Cambridge, and UK Gaia DPAC Project Manager, comments: "Gaia is measuring the distances of hundreds of millions of objects that are many thousands of light years away, at an accuracy equivalent to measuring the thickness of hair at a distance of more than 2000 kilometres. These data are one of the backbones of astrophysics, allowing us to forensically analyse our stellar neighbourhood, and tackle crucial questions about the origin and future of our Galaxy."

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Scientists peer into the 3D structure of the Milky Way

 Scientists from Cardiff University have helped produce a brand-new, three-dimensional survey of our galaxy, allowing them to peer into the inner structure and observe its star-forming processes in unprecedented detail.

The large-scale survey, called SEDIGISM (Structure, Excitation and Dynamics of the Inner Galactic Interstellar Medium), has revealed a wide range of structures within the Milky Way, from individual star-forming clumps to giant molecular clouds and complexes, that will allow astronomers to start pushing the boundaries of what we know about the structure of our galaxy.

SEDIGISM has been unveiled today through the publication of three separate papers in the Monthly Notices of the Royal Astronomical Society, authored by an international team of over 50 astronomers.

"With the publication of this unprecedentedly detailed map of cold clouds in our Milky Way, a huge observational effort comes to fruition," says Frederic Schuller from the Max Planck Institute for Radio Astronomy (MPIfR), lead author of one of the three publications, presenting the data release.

Dr Ana Duarte Cabral, a Royal Society University Research Fellow from Cardiff University's School of Physics and Astronomy, was lead author on one of the papers and has provided a catalogue of over 10,000 clouds of molecular gas in our Milky Way.

The Milky Way, named after its hazy appearance from Earth, is a spiral galaxy with an estimated diameter between 170,000 and 200,000 light-years which contains between 100-400 billion stars.

The Milky Way consists of a core region that is surrounded by a warped disk of gas and dust that provides the raw materials from which new stars are formed.

For Dr Duarte Cabral, the new catalogue of gas clouds will allow scientists to probe exactly how the spiral structure of our own Milky Way affects the life cycle of clouds, their properties, and ultimately the star formation that goes on within them.

"What is most exciting about this survey is that it can really help pin down the global galactic structure of the Milky Way, providing an astounding 3D view of the inner galaxy," she said.

"With this survey we really have the ability to start pushing the boundaries of what we know about the global effects of the galactic structures and dynamics, in the distribution of molecular gas and star formation, because of the improved sensitivity, resolution, and the 3D view."

The catalogue of molecular gas clouds was created by measuring the rare isotope of the carbon monoxide molecule, 13CO, using the extremely sensitive 12-metre Atacama Pathfinder Experiment telescope on the Chajnantor plateau in Chile.

This allowed the team to produce more precise estimates of the mass of the gas clouds and discern information about their velocity, therefore providing a truly three-dimensional picture of the galaxy.

Dr Duarte Cabral and colleagues are already beginning to tease out information from the vast amount of data at their disposal.

"The survey revealed that only a small proportion, roughly 10%, of these clouds have dense gas with ongoing star formation," said James Urquhart from the University of Kent, the lead author of the third publication.

Similarly, the results from the work led by Dr Duarte Cabral suggest that the structure of the Milky Way is not that well defined and that the spiral arms are not that clear.

They have also shown that the properties of clouds do not seem to be dependent on whether a cloud is located in a spiral arm or an inter-arm region, where they expected very different physics to be playing a role.

"Our results are already showing us that the Milky Way may not be a strong grand design type of spiral galaxy as we thought, but perhaps more flocculent in nature," Dr Duarte Cabral continued.

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Patients with heart rhythm disorder warned against heavy alcohol consumption

 Fourteen drinks a week is linked with a higher risk of health problems including stroke and embolism in patients with atrial fibrillation, according to research published in EP Europace, a journal of the European Society of Cardiology (ESC).

"Our study suggests that atrial fibrillation patients should avoid heavy alcohol consumption to prevent stroke and other complications," said author Dr. Boyoung Joung of Yonsei University College of Medicine, Seoul, Republic of Korea.

The study included 9,411 patients with atrial fibrillation from 18 tertiary hospitals covering all geographical regions of South Korea. Patients were categorised into four groups according to their weekly alcohol consumption (one drink contains 14 grams of alcohol): abstainer/rare (0 grams/less than one drink), light (less than 100 grams/7 drinks), moderate (100-200 grams/7-14 drinks), and heavy (200 grams/14 drinks or more).

A total of 7,455 (79.2%) patients were classified as abstainer/rare, 795 (8.4%) as light, 345 (3.7%) as moderate, and 816 (8.7%) as heavy alcohol consumption.

Patients were followed-up for a median of 17.4 months for adverse events, which included stroke, transient ischaemic attack, systemic embolism (a blood clot in a limb or organ), and hospitalisation for rate or rhythm control of atrial fibrillation or for heart failure management. The researchers recorded how many patients experienced any of these events and calculated the incident rate (number of events per 100 person-years). Incident rates were 6.73, 5.77, 6.44, and 9.65 in the abstainer/rare, light, moderate, and heavy drinkers, respectively.

The researchers compared the risk of adverse events in the light, moderate, and heavy drinkers to the abstainer/rare group. Heavy drinking was associated with a 32% increased risk compared with the abstainers and rare drinkers. No significant association was observed for light or moderate alcohol consumption.

Dr. Joung said: "Our study did not find any significant association between light or moderate drinking and complications. A significant deleterious relationship with heavy drinking was identified, suggesting that heavy alcohol consumption should be avoided."

Subgroup analyses showed that the impact of heavy drinking was more pronounced in patients with low stroke risk2 compared to those at moderate or high stroke risk. Similarly, heavy drinking was associated with a greater likelihood of unfavourable outcomes in patients without high blood pressure compared to those with high blood pressure. Higher risks were also observed in patients not using beta-blockers or antiplatelet medications compared to those taking the drugs.

Dr. Joung said: "The findings indicate that heavy drinking is particularly detrimental for atrial fibrillation patients who are considered less vulnerable to complications. Clinicians should ask patients about their alcohol consumption and take it into account when calculating their stroke risk."

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The tree of cortical cell types describes the diversity of neurons in the brain

The tree of life describes the evolution of life and seeks to define the relationships between species. Likewise, the tree of cell types aims to organize cells in the brain into groups and describe their relationships to each other.

Scientists have long pondered just what the brain's tree of cell types looks like. Now, an international collaboration led by Dr. Andreas Tolias from Baylor College of Medicine, Dr. Philipp Berens from the University of Tübingen in Germany and Dr. Rickard Sandberg from the Karolinska Institute in Stockholm, Sweden, has published an article in Nature that provides one of the most detailed and complete characterizations of the diversity of neural types in the brain so far.

Uncovering the shape of the tree of cortical cell types with Patch-seq

Neuroscientists mostly use three fundamental features to describe neurons: their anatomy, or how they look under a microscope; their physiology, or how they respond when stimulated; and, more recently, the genes they express, which are known as their transcriptome.

For this study, the research team used an experimentally challenging technique that they developed several years ago, called Patch-seq. This technique allowed them to collect a large multimodal database including genetic, anatomical and physiological information from single cells in the mouse motor cortex.

"Gathering all these three fundamental features from the same set of neurons was the key that enabled us to get a much deeper understanding of how neurons in the motor cortex are related to each other and a clearer view of how the tree of cell types looks like," said co-first author Dr. Federico Scala, postdoctoral associate in Tolias lab at Baylor.

Dr. Dmitry Kobak, also co-first author and a research scientist in Berens lab, described that while the broad genetic families of neurons had distinct anatomical and physiological properties, within each family the neurons exhibited extensive anatomical and physiological diversity. Importantly, all the three basic neuronal characteristics (anatomy, physiology and transcriptome) were correlated, which enabled the team to find interesting links between them.

"Our data supports the view that the tree of cortical cell types may look more like a banana tree with few big leaves rather than an olive tree with many small ones. This view provides a simpler model to describe the diversity of neurons we find in the brain. We believe that this simpler view will lead to a more principled understanding of why we have so many cell types in the brain to begin with and what they are used for," said Tolias, Brown Foundation Endowed Chair of Neuroscience and director of the Center for Neuroscience and Artificial Intelligence at Baylor.

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Greenland ice sheet faces irreversible melting

 

Illustration of northern Canada and Greenland from space.

In a study published this week in The Cryosphere, researchers from the National Centre for Atmospheric Science and University of Reading demonstrate how climate change could lead to irreversible sea level rise as temperatures continue to rise and the Greenland ice sheet continues to decline.

The massive ice sheet faces a point of no return, beyond which it will no longer fully regrow, permanently changing sea levels around the world.

The Greenland ice sheet is seven times the area of the UK, and stores a large amount of the Earth's frozen water. At current rates of melting, it contributes almost 1mm to sea level per year, and accounts for around a quarter of total sea level rise.

Since 2003, despite seasonal periods of growth, Greenland's ice sheet has lost three and a half trillion tonnes of ice.

Rising sea levels are one of the most severe effects of climate change, threatening coastal areas around the world, and putting millions of people who live in low-lying areas at risk. Bangladesh, Florida, and eastern England are among many areas known to be particularly vulnerable.

Under scenarios in which global warming goes beyond 2°C, the Paris Agreement target, we should expect significant ice loss and several metres of global sea level rise to persist for tens of thousands of years, according to the new research. The warmer the climate, the greater the sea-level rise.

In addition, even if temperatures later return to current levels, scientists have shown that the Greenland ice sheet will never fully regrow once it melts beyond a critical point. After that point, sea levels would permanently remain two meters higher than now, regardless of other factors contributing to sea level rise.

This is because the ice sheet is so large that it has a substantial impact on its local climate, and as it declines, Greenland would experience warmer temperatures and less snowfall.

Once the ice-sheet retreats from the Northern part of the island, the area would remain ice-free.

To avoid the irreversible sea level rise the melting would cause, scientists say that climate change must be reversed before the ice sheet has declined to the threshold mass, which would be reached in about 600 years at the highest rate of mass loss within the likely range of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

Professor Jonathan Gregory, Climate Scientist from the National Centre for Atmospheric Science and University of Reading, said: "Our experiments underline the importance of mitigating global temperature rise. To avoid partially irreversible loss of the ice sheet, climate change must be reversed -- not just stabilised -- before we reach the critical point where the ice sheet has declined too far."

To study the ice-sheet, scientists from the National Centre for Atmospheric Science simulated the effects of Greenland ice sheet melting under a range of possible temperature rises, ranging from minimal warming to worst-case scenarios.

Under all future climates like the present or warmer, the ice-sheet declined in size and contributed to some degree of sea-level rise.

Importantly, there were scenarios in which the ice sheet melting could be reversed. But, they rely on actions to counteract global warming before it's too late.

Read more at Science Daily

A hint of new physics in polarized radiation from the early universe

 

Milky Way galaxy in the night sky.

Using Planck data from the cosmic microwave background radiation, an international team of researchers has observed a hint of new physics. The team developed a new method to measure the polarization angle of the ancient light by calibrating it with dust emission from our own Milky Way.

While the signal is not detected with enough precision to draw definite conclusions, it may suggest that dark matter or dark energy causes a violation of the so-called "parity symmetry."

The laws of physics governing the Universe are thought not to change when flipped around in a mirror. For example, electromagnetism works the same regardless of whether you are in the original system, or in a mirrored system in which all spatial coordinates have been flipped.

If this symmetry, called "parity," is violated, it may hold the key to understanding the elusive nature of dark matter and dark energy, which occupy 25 and 70 percent of the energy budget of the Universe today, respectively. While both dark, these two components have opposite effects on the evolution of the Universe: dark matter attracts, while dark energy causes the Universe to expand ever faster.

A new study, including researchers from the Institute of Particle and Nuclear Studies (IPNS) at the High Energy Accelerator Research Organization (KEK), the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) of the University of Tokyo, and the Max Planck Institute for Astrophysics (MPA), reports on a tantalizing hint of new physics -- with 99.2 percent confidence level -- which violates parity symmetry.

Their findings were published in the journal Physical Review Letters on November 23, 2020.

The hint to a violation of parity symmetry was found in the cosmic microwave background radiation, the remnant light of the Big Bang. The key is the polarized light of the cosmic microwave background. Light is a propagating electromagnetic wave. When it consists of waves oscillating in a preferred direction, physicists call it "polarized." The polarization arises when the light is scattered.

Sunlight, for instance, consists of waves with all possible oscillating directions; thus, it is not polarized. The light of a rainbow, meanwhile, is polarized because the sunlight is scattered by water droplets in the atmosphere. Similarly, the light of the cosmic microwave background initially became polarized when scattered by electrons 400,000 years after the Big Bang. As this light traveled through the Universe for 13.8 billion years, the interaction of the cosmic microwave background with dark matter or dark energy could cause the plane of polarization to rotate by an angle.

"If dark matter or dark energy interact with the light of the cosmic microwave background in a way that violates parity symmetry, we can find its signature in the polarization data," points out Yuto Minami, a postdoctoral fellow at IPNS, KEK.

To measure the rotation angle, the scientists needed polarization-sensitive detectors, such as those onboard the Planck satellite of the European Space Agency (ESA). And they needed to know how the polarization-sensitive detectors are oriented relative to the sky. If this information was not known with sufficient precision, the measured polarization plane would appear to be rotated artificially, creating a false signal.

In the past, uncertainties over the artificial rotation introduced by the detectors themselves limited the measurement accuracy of the cosmic polarization angle.

"We developed a new method to determine the artificial rotation using the polarized light emitted by dust in our Milky Way," said Minami. "With this method, we have achieved a precision that is twice that of the previous work, and are finally able to measure the (polarization angle)."

The distance traveled by the light from dust within the Milky Way is much shorter than that of the cosmic microwave background. This means that the dust emission is not affected by dark matter or dark energy, i.e. (the polarization angle) is present only in the light of the cosmic microwave background, while the artificial rotation affects both. The difference in the measured polarization angle between both sources of light can thus be used to measure (the angle).

The research team applied the new method to measure (the angle) from the polarization data taken by the Planck satellite. They found a hint for violation of parity symmetry with 99.2 percent confidence level. To claim a discovery of new physics, much greater statistical significance, or a confidence level of 99.99995 percent, is required.

Eiichiro Komatsu, director at the MPA and Principal Investigator at the Kavli IPMU, said: "It is clear that we have not found definitive evidence for new physics yet; higher statistical significance is needed to confirm this signal. But we are excited because our new method finally allowed us to make this 'impossible' measurement, which may point to new physics."

Read more at Science Daily

Fingerprints' moisture-regulating mechanism strengthens human touch

 

Fingerprint ridges close-up.

Human fingerprints have a self-regulating moisture mechanism that not only helps us to avoid dropping our smartphone, but could help scientists to develop better prosthetic limbs, robotic equipment and virtual reality environments, a new study reveals.

Primates -- including humans, monkeys and apes -- have evolved epidermal ridges on their hands and feet with a higher density of sweat glands than elsewhere on their bodies. This allows precise regulation of skin moisture to give greater levels of grip when manipulating objects.

Fingerprints help to increase friction when in contact with smooth surfaces, boost grip on rough surfaces and enhance tactile sensitivity. Their moisture-regulating mechanism ensures the best possible hydration of the skin's keratin layer to maximise friction.

Researchers at the University of Birmingham worked with partners at research institutions in South Korea, including Seoul National University and Yonsei University -- publishing their findings today in Proceedings of the National Academy of Sciences (PNAS).

Co-author Mike Adams, Professor in Product Engineering and Manufacturing, at the University of Birmingham commented: "Primates have evolved epidermal ridges on their hands and feet. During contact with solid objects, fingerprint ridges are important for grip and precision manipulation. They regulate moisture levels from external sources or the sweat pores so that friction is maximised and we avoid 'catastrophic' slip and keep hold of that smartphone."

"Understanding the influence of finger pad friction will help us to develop more realistic tactile sensors -- for example, applications in robotics and prosthetics and haptic feedback systems for touch screens and virtual reality environments."

Ultrasonic lubrication is commonly used in touch screen displays that provide sensory 'haptic' feedback, but its effectiveness is reduced when a user has dry compared with moist finger pads. Moreover, being able to distinguish between fine-textured surfaces, such as textiles, by touch relies on the induced lateral vibrations but the absence of sliding friction inhibits our ability to identify what we are actually touching.

Fingerprints are unique to primates and koalas -- appearing to have the dual function of enhancing evaporation of excess moisture whist providing a reservoir of moisture at their bases that enables grip to be maximised.

The researchers have discovered that, when finger pads are in contact with impermeable surfaces, the sweat from pores in the ridges makes the skin softer and thus dramatically increases friction. However, the resulting increase in the compliance of the ridges causes the sweat pores eventually to become blocked and hence prevents excessive moisture that would reduce our ability to grip objects.

Using hi-tech laser-based imaging technology, the scientists found that moisture regulation could be explained by the combination of this sweat pore blocking and the accelerated evaporation of excessive moisture from external wetting as a result of the specific cross-sectional shape of the epidermal furrows when in contact with an object.

These two functions result in maintaining the optimum amount of moisture in the fingerprint ridges that maximises friction whether the finger pad is initially wet or dry.

Read more at Science Daily

Researchers determine how the SARS-CoV-2 virus hijacks and rapidly causes damage to human lung cells

 

Illustration of SARS-CoV-2 viruses infecting human lung cells.

In a multi-group collaborative involving the National Emerging Infectious Disease Laboratories (NEIDL), the Center for Regenerative Medicine (CReM), and the Center for Network Systems Biology (CNSB), scientists have reported the first map of the molecular responses of human lung cells to infection by SARS-CoV-2. By combining bioengineered human alveolar cells with sophisticated, highly precise mass spectrometry technology, Boston University School of Medicine (BUSM) researchers have identified host proteins and pathways in lung cells whose levels change upon infection by the SARS-CoV-2, providing insights into disease pathology and new therapeutic targets to block COVID-19.

They found a crucial type of protein modification called "phosphorylation" becomes aberrant in these infected lung cells. Phosphorylation of proteins play a major role in regulating protein function inside the cells of an organism and both protein abundance and protein phosphorylation are typically highly controlled processes in the case of normal/healthy cells. However, they discovered that SARS-CoV-2 throws the lung cells into disarray, causing abnormal changes in protein amounts and frequency of protein phosphorylation inside these cells. These abnormal changes help the virus to multiply eventually destroy the cells. The destruction of infected cells may result in widespread lung injury.

According to the researchers, as soon as the SARS-CoV-2 enters the lung cells, it rapidly begins to exploit the cell's core resources, which are otherwise required for the cell's normal growth and function. "The virus uses these resources to proliferate while evading attack by the body's immune system. In this way new viruses form which subsequently exit the exhausted and brutally damaged lung cell, leaving them to self-destruct. These new viruses then infect other cells, where the same cycle is repeated," explains corresponding author Andrew Emili, PhD, professor of biochemistry at BUSM.

The researchers examined lung alveolar cells from one to 24 hours after infection with SARS-CoV-2 to understand what changes occur in lung cells immediately (at one, three and six hours after infection by SARS-CoV-2) and what changes occur later (at 24 hours after infection). These changes were then compared to uninfected cells. All proteins from infected and uninfected alveolar cells, corresponding to the different time-points were extracted and labelled with unique barcoding tags called "tandem mass tag." These tags, which can be accurately detected only by a mass spectrometer, permit robust quantification of protein and phosphorylation abundance in cells.

"Our results showed that in comparison to normal/uninfected lung cells, SARS-CoV-2 infected lung cells showed dramatic changes in the abundance of thousands of proteins and phosphorylation events," said Darrell Kotton, MD, professor of pathology & laboratory medicine at BUSM and director of the CReM.

"Moreover, our data also showed that the SARS-CoV-2 virus induces a significant number of these changes as early as one hour post infection and lays the foundation for a complete hijack of the host lung cells," adds Elke M?hlberger, PhD, associate professor of microbiology and principal investigator at the NEIDL.

"There are important biological features specific to lung cells that are not reproduced by other cell types commonly used to study viral infection," said Andrew Wilson, MD, associate professor of medicine at BUSM and CReM investigator. "Studying the virus in the context of the cell type that is most damaged in patients is likely to yield insights that we wouldn't be able to see in other model systems."

The researchers also analyzed their data to identify prospective opportunities for COVID-19 treatment and found that at least 18 pre-existing clinically approved drugs (developed originally for other medical conditions/diseases) can be potentially re-purposed for use towards COVID-19 therapy. These drugs have shown exceptional promise to block the proliferation of the SARS-CoV-2 in lung cells.

The researchers believe this information is invaluable and paves the way for newer, potentially promising and more importantly, a cost-effective and time-saving therapeutic strategy to combat COVID-19.

Read more at Science Daily

Experiments unravelling the mystery of Mars' moon Phobos

 Of course, there is no weather in our sense of the word in space -- nevertheless, soil can also "weather" in the vacuum of space if it is constantly bombarded by high-energy particles, such as those emitted by the sun. The Martian moon Phobos is affected by a special situation: it is so close to Mars that not only the solar wind but also the irradiation by particles from Mars plays a decisive role there. A research team from TU Wien has now been able to measure this in laboratory experiments. In just a few years, a Japanese space mission will take soil samples from Phobos and bring them back to Earth.

Billions of years of particle irradiation

"There are different theories of how the Mars moon Phobos could have formed," says Paul Szabo, who is working on his PhD thesis in the research group of Prof. Friedrich Aumayr at the Institute of Applied Physics at TU Wien. "It is possible that Phobos was originally an asteroid that was then captured by Mars, but it could also have been created by a collision of Mars with another large object."

When investigating such celestial bodies, one must always bear in mind that their surfaces have been completely changed over billions of years by cosmic particle bombardment. The surface of the Earth remains unaffected by this, because our atmosphere shields the particles. However, the geology of celestial bodies without atmospheres, such as our Moon or Phobos, can only be understood if it is possible to correctly assess "space weathering."

Therefore, elaborate experiments were conducted at TU Wien: "We used a mineral like it is found on Phobos and bombarded it in vacuum chambers with different charged particles," explains Paul Szabo. "Using an extremely precise balance, we can measure how much material is removed in the process and how much each particle affects the surface.

The special properties of the moon Phobos must be taken into account: Its distance from the surface of Mars is less than 6000 km -- not even two percent of the distance between our Moon and the Earth. Just like our Moon, it is in a tidally locked rotation around its planet: The same side always faces Mars.

"Because of the extremely small distance between Mars and Phobos, not only particles emitted from the Sun play a role on the surface of Phobos, but also particles from Mars," says Paul Szabo. The Martian atmosphere consists mainly of carbon dioxide. But in the outer regions of the atmosphere there are also larger amounts of oxygen. When particles from the solar wind penetrate there, oxygen ions can be created, which then hit Phobos at high speed and change the surface material.

Data for 2024 space mission

"With our measuring methods we were able to estimate the erosion of Phobos much more accurately than was previously possible," says Friedrich Aumayr. "Our results show that the effect of oxygen ions from the Martian atmosphere cannot be neglected. It is also important to distinguish between the two sides of Phobos: While the solar wind causes the weathering on the side facing away from Mars, the bombardment from the Martian atmosphere dominates on the other side, when the Sun is shielded from Mars.

Read more at Science Daily

Breaking the rules of chemistry unlocks new reaction

 Scientists have broken the rules of enzyme engineering to unlock a new method for creating chemical reactions that could unlock a wide range of new applications -- from creating new drugs to food production.

In their paper published today in Nature Catalysis, Professor Francesca Paradisi and Dr. Martina Contente of the University of Nottingham and the University of Bern show a new method to produce chemical molecules more efficiently through a new one step reaction in the enzyme.

Professor Paradis is Professor of Biocatalysis in the School of Chemistry in Nottingham and Professor of Pharmaceutical Chemistry at the University of Bern, she explains: "We have demonstrated how a very simple mutation in one of the key residues of a useful enzyme has dramatically expanded its synthetic scope, enabling the use of the mutant variant in the preparation of challenging chemical molecules, as well as natural metabolites that are vital in many biological processes in the body."

Any textbook on enzymes will report on how the catalytic amino acids in any given enzyme family are highly conserved, they are in fact a signature of the type of chemistry an enzyme can do. Variations do occur and in some cases, if the replacing amino acid is similar, both can be found in significant proportion in Nature, but others can be much less common and are found only in a limited number of species.

"In this study we have explored an untouched area of enzyme engineering and modified the a key catalytic residue in the active site of an enzyme" adds Professor Paradisi, "Previously it was thought that doing this would cause a loss of activity of the enzyme but we have found this is not the case when this biocatalyst is used in a synthetic direction and in fact challenging but very useful molecules can now be made under mild conditions which could be easily scaled up and replicated commercially for use in a wide range of products."

To change the substrate scope of an enzyme the approach has generally been to mutate the residues involved in substrate recognition, whether through rational design or directed evolution, leaving always untouched the catalytic ones.

The mutant variant of an acyl transferase enzyme was rapidly created and while the native biocatalyst would work with alcohols and linear amines, the mutant work with thiols and much more complex amines too. The research demonstrated that indeed the new variant has lost the ability to hydrolyse esters, but for synthetic applications, where an ester or other functional groups need to be made (thioesters and amides) and not cleaved, this is in fact a major advantage.

Read more at Science Daily

Study shows strong links between music and math, reading achievement

 Music educator Martin J. Bergee thought that if he could just control his study for the myriad factors that might have influenced previous ones -- race, income, education, etc. -- he could disprove the notion of a link between students' musical and mathematical achievement.

Nope. His new study,"Multilevel Models of the Relationship Between Music Achievement and Reading and Math Achievement," published in the Journal of Research in Music Education, showed statistically significant associations between the two at both the individual and the school-district levels. That the study of more than 1,000 mainly middle-school-aged students showed no such association at the classroom or school levels only shows how rigorously it was conceived by Bergee, a professor in the University of Kansas School of Music, and his co-author and Ph.D. student, currently a visiting professor of music education at the University of Washington, Kevin M. Weingarten.

The study has implications for school-board members considering budgets that impact music programs. It adds to the body of scientific research showing linkages between music and math/reading. And in his conclusion, Bergee even suggests some specific reasons for why that might be.

"There has been this notion for a long time," Bergee said recently, "that not only are these areas related, but there's a cause-and-effect relationship -- that as you get better in one area, you will, per se, get better in another area. The more you study music, the better you're going to be at math or reading. That's always been suspect with me.

"I've always believed that the relationship is correlational and not causational. I set out to demonstrate that there are probably a number of background variables that are influencing achievement in any academic area -- in particular, things like the educational level of the family, where the student lives, whether they are white or non-white, and so forth.

"Those variables are in the article, and there are about lots of them. My intention was to was to show that the relationships are probably spurious, meaning that background influences are the main drivers of the relationships, and once those outside influences, like demographics, etc., are controlled for, the relationship essentially disappears.

"But hang on. Much to my surprise, not only did they not disappear, but the relationships are really strong."

Bergee "apologizes for the complexity" of the study's design, but said "it's not an easy thing to determine, because there are influences that can happen at different levels. It can be an influence at the level of the individual person, but there are also influences that can happen at the classroom, school and school-district level, and those are hierarchical. That involves a complicated set of analyses.

Even though he was prepared to write "a completely different conclusion," Bergee said he has thought a lot about what the findings show.

The authors write that: "Perhaps music discrimination at a more micro level -- pitches, intervals, meters -- shares a cognitive basis with certain patterns of discrimination in speech. Similarly, perhaps the more macro skills of modal and tonal center discrimination share some psychological or neurological space with aspects of math cognition. ... Results of the present study ... at least point to the possibility."

In a recent interview, Bergee said, "Based on the findings, the point we tried to make is that there might be, and probably are, general learning processes that underlie all academic achievement, no matter what the area is. Music achievement, math achievement, reading achievement -- there are probably more generalized processes of the mind that are brought to bear on any of those areas.

"Therefore, if your goal is to educate the person -- to develop the person's mind -- then you need to educate the whole person. In other words, learning may not be as modular as it is often thought to be."

It implies more than introducing children to subjects, Bergee said: "Develop them in these subjects. See that learning is taking place. See that development is, too." Bergee said his study wasn't intended to show that learning music will necessarily improve a child's math or reading scores.

"It would not be impossible, but really difficult to do a truly definitive study," Bergee said. "My inclination is that it would not show a strong effect, but that's what I said about this study! I actually don't know."

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Key molecules in brain development and neurodegenerative diseases identified

Neurological diseases of the brain such as dementia, autism and schizophrenia are now a growing social problem. Nevertheless, studies on their definitive cause are still insufficient. Recently, a POSTECH research team has identified the mechanism in which such neurological diseases occur, thus solving the enigma to treating them.

In the case of neurological diseases of the brain, problems arise when certain effects modify the synaptic plasticity and signal transmissions of the brain-derived neurotrophic factor (BDNF), which has a profound effect on the development and differentiation of neurons. The information between nerve cells is transferred through synapses, where the synaptic activity and the synaptic structure are dynamically changed and regulated according to stimulations. During this moment, BDNF has prominent effects on the survival and synaptic plasticity of nerve cells. When it malfunctions, it not only interferes with the smooth information exchange between the brain cells but also kills neurons, leading to learning and memory impairment.

Professor Kyong-Tai Kim and Dr. Young-Seop Jeong of POSTECH's Division of Integrative Biosciences and Biotechnology have identified the mechanism by which BDNF regulates the local expression of AMPA receptors, which are important for synaptic function of nerve cells. The findings of the study were published in the November issue of Science Advances.

AMPA receptors are ion channel receptors that glutamic acid acts on and are responsible for excitatory neural signals. They are located on the dendrites' spines of nerve cells and transmit signals when they recognize glutamic acid secreted in the synapses. For synaptic plasticity, it is normal for the AMPA receptors to synthesize locally and efficiently translocate to the postsynaptic membrane according to the strength, duration, and frequency of neural stimulation. The presence of the AMPA receptor mRNA in the dendrites was already known, but the mechanism of how this mRNA is translated into a receptor protein was unknown until now.

The research team found that there is an internal ribosome entry site (IRES) activity in the 5' untranslated region of the AMPA receptor mRNA, and unlike the general method, protein translation increases when a protein hnRNP A2/B1 -- an RNA-binding protein -- binds to this site.

It was confirmed that the AMPA receptor mRNA, created by transcription from the nucleus, moves to the dendrites and waits there until a simulation occurs to quickly produce receptor proteins in response to various stimuli. In particular, when BDNF stimulates nerve cells, the amount of hnRNP A2/B1 increases, thus promoting the synthesis of AMPA receptor proteins. These proteins locally synthesized in the synapses efficiently carry out the neural signal transduction.

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New Hubble data explains missing dark matter

 The missing dark matter in certain galaxies can be explained by the effects of tidal disruption: the gravity forces of a neighboring massive galaxy, literally tearing the smaller galaxy apart.

In 2018 an international team of researchers using the NASA/ESA Hubble Space Telescope and several other observatories uncovered, for the first time, a galaxy in our cosmic neighborhood that is missing most of its dark matter. This discovery of the galaxy NGC 1052-DF2 was a surprise to astronomers, as it was understood that dark matter is a key constituent in current models of galaxy formation and evolution. In fact, without the presence of dark matter, the primordial gas would lack enough gravitational pull to start collapsing and forming new galaxies. A year later, another galaxy that misses dark matter was discovered, NGC 1052-DF4, which further triggered intense debates among astronomers about the nature of these objects.

Now, new Hubble data have been used to explain the reason behind the missing dark matter in NGC 1052-DF4, which resides 45 million light-years away. Mireia Montes of the University of New South Wales in Australia led an international team of astronomers to study the galaxy using deep optical imaging. They discovered that the missing dark matter can be explained by the effects of tidal disruption. The gravity forces of the neighboring massive galaxy NGC 1035 are tearing NGC 1052-DF4 apart. During this process, the dark matter is removed, while the stars feel the effects of the interaction with another galaxy at a later stage.

Until now, the removal of dark matter in this way has remained hidden from astronomers as it can only be observed using extremely deep images that can reveal extremely faint features. "We used Hubble in two ways to discover that NGC 1052-DF4 is experiencing an interaction," explained Montes. "This includes studying the galaxy's light and the galaxy's distribution of globular clusters."

Thanks to Hubble's high resolution, the astronomers could identify the galaxy's globular cluster population. The 10.4-meter Gran Telescopio Canarias (GTC) telescope and the IAC80 telescope in the Canary Islands of Spain were also used to complement Hubble's observations by further studying the data.

"It is not enough just to spend a lot of time observing the object, but a careful treatment of the data is vital," explained team member Raúl Infante-Sainz of the Instituto de Astrofísica de Canarias in Spain. "It was therefore important that we use not just one telescope/instrument, but several (both ground- and space-based) to conduct this research. With the high resolution of Hubble, we can identify the globular clusters, and then with GTC photometry we obtain the physical properties."

Globular clusters are thought to form in the episodes of intense star formation that shaped galaxies. Their compact sizes and luminosity make them easily observable, and they are therefore good tracers of the properties of their host galaxy. In this way, by studying and characterizing the spatial distribution of the clusters in NGC 1052-DF4, astronomers can develop insight into the present state of the galaxy itself. The alignment of these clusters suggests they are being "stripped" from their host galaxy, and this supports the conclusion that tidal disruption is occurring.

By studying the galaxy's light, the astronomers also found evidence of tidal tails, which are formed of material moving away from NGC 1052-DF4. This further supports the conclusion that this is a disruption event. Additional analysis concluded that the central parts of the galaxy remain untouched and only about 7% of the stellar mass of the galaxy is hosted in these tidal tails. This means that dark matter, which is less concentrated than stars, was previously and preferentially stripped from the galaxy, and now the outer stellar component is starting to be stripped as well.

"This result is a good indicator that, while the dark matter of the galaxy was evaporated from the system, the stars are only now starting to suffer the disruption mechanism," explained team member Ignacio Trujillo of the Instituto de Astrofísica de Canarias in Spain. "In time, NGC 1052-DF4 will be cannibalized by the large system around NGC 1035, with at least some of their stars floating free in deep space."

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Puzzling 'cold quasar' forming new stars in spite of active galactic nucleus

 Researchers from the University of Kansas have described a galaxy more than 5.25 billion light years away undergoing a rarely seen stage in its galactic life cycle. Their findings recently were published in the Astrophysical Journal.

The galaxy, dubbed CQ 4479, shows characteristics that normally don't coexist: an X-ray luminous active galactic nuclei (AGN) and a cold gas supply fueling high star formation rates.

"Massive galaxies, such as our own Milky Way, host a supermassive black hole at their hearts -- these are black holes that grow by accreting interstellar gas onto themselves to become more massive," said Kevin Cooke, lead author and postdoctoral researcher in KU's Department of Physics & Astronomy. "The end of galactic growth is thought to happen when this gas accretion onto the black hole occurs in sufficient quantities that it produces a tremendous amount of energy. Then, all of that energy surrounding the black hole will actually heat up the rest of the gas throughout the galaxy in such a way that it can't condense any more to form stars and the galaxy's growth stops."

The KU researchers instead found CQ 4479, a galaxy which never had been closely studied before, to be still generating new stars in spite of the luminous AGN at the galaxy's center.

"Normally, we expect that to shut everything else off," Cooke said. "But instead, we see massive amounts of new stars being formed in this galaxy. So, it's a very limited time window where you can see both the black hole growing and the stars surrounding it growing at the same time."

The researchers observed the cold quasar primarily using NASA's SOFIA infrared telescope, which is flown aboard a Boeing 747 aircraft. Other measurements were made using FUV-FIR photometry and optical spectroscopy. The work was supported by a NASA grant to primary investigator Allison Kirkpatrick, assistant professor of physics & astronomy at KU, who co-wrote the new paper.

Kirkpatrick said the team's various methods of observing the galaxy showed contradictory data, making the nature of CQ 4479 even more of a puzzle.

"What's really unique about this source is we have different measurements of the energy output near the black hole," Kirkpatrick said. "That tells you how fast the black hole is growing and also its feedback into the host galaxy that can shut down star formation. We have everything from X-ray, to optical and the infrared, so we're able to measure several different signatures of the black hole's energy output. And the signatures don't agree -- that's really rare. One interpretation is the growth of the black hole is slowing, because the X-rays come from right next to the black hole, while the optical signatures come from a little bit further out, and the infrared signatures come from further out as well. Essentially, less energy seems to be being produced right around the black hole now than it was in the past."

The researchers seem to be looking at a snapshot of the galaxy during a pivotal stage of its lifespan.

"I think this is a galaxy undergoing a midlife crisis," Kirkpatrick said. "It's going through one last burst of star formation. Most of its solar mass is already in place. It's forming a few more stars now, and the thing that's ultimately going to kill it is starting to kick in."

In part, the research at KU was performed by Kirkpatrick's undergraduate student and co-author Michael Estrada, now a graduate student at University of Florida.

"He did the data analysis of the optical spectroscopy and measured the black hole mass for us," Kirkpatrick said.

Other questions about the physical structure of the galaxy remain because current instrumentation available to astronomers don't provide clear enough images of CQ 4479.

"The image we have shows a central blob and then a little smaller blob below it," Kirkpatrick said. "So we don't have a good sense for how this galaxy looks because the central AGN is so bright that it out shines the rest of the host galaxy. This is a real problem that plagues all AGN studies -- when you're dealing with the most luminous things they tend to outshine your host at nearly every wavelength."

The researchers said CQ 4479 would require more study, particularly using the ALMA Observatory and the NASA's James Webb Space Telescope -- the most powerful space telescope ever designed and currently slated for launch Oct. 31, 2021. Both Cooke and Kirkpatrick hope to perform more investigations of the strange cold quasar once the telescope is launched.

"We're currently banking on James Webb, because it will have excellent resolution and we should be able to look at wavelengths where we can see the shape of the galaxy," Kirkpatrick said. "Another good option would be ALMA. But ALMA has unfortunately shut down temporarily because of COVID. We've kind of been stymied at seeing the host galaxy."

The importance of understanding the strange processes underway in a galaxy 5.25 billion light years from Earth might seem vague at first, but Cooke said a better understanding of the cold quasar could improve understanding of the cosmos and the fate of our own galaxy.

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How 'smell training' could help overcome post-viral smell distortions

 If you've been experiencing odour distortions after Covid-19, then 'smell training' could help you start smelling normally again -- according to new research involving the University of East Anglia.

Parosmia is a symptom where people experience strange and often unpleasant smell distortions. Instead of smelling a lemon you may smell rotting cabbage, or chocolate may smell like petrol. The symptom has been linked to smell disturbance in Covid-19, as well as due to other viruses and head injuries.

A new paper published today shows that the presence of parosmia is associated with clinically relevant recovery in smell performance (identifying and distinguishing smells) in patients with smell loss caused by viral infections who are undertaking smell training.

The research was led by the Technical University of Dresden (Germany) in collaboration with the University of East Anglia (UK), the Norfolk Smell and Taste Clinic at the James Paget University Hospital (UK), the Medical University of Vienna (Austria), University Hospitals of Cologne (Germany), and the University of Wroclaw (Poland).

Prof Carl Philpott from UEA's Norwich Medical School, said: "Some degree of smell loss is thought to affect up to one quarter of the general population.

"Smell loss is also a prominent symptom of Covid-19, and we know that the pandemic is leaving many people with long-term smell loss, or smell distortions such as parosmia -- this may now be as many as 90,000 people in the UK.

"For people with parosmia, the smell of certain things -- or sometimes everything -- is different, and often unpleasant. So for example, someone with parosmia could sniff at a cinnamon stick, but to them it would smell like something horrible -- perhaps rotten food, or worse.

"Smell training involves sniffing at least four different odours twice a day every day for several months. It has emerged as a simple and side-effect free treatment option for various causes of smell loss.

"It aims to help recovery based on neuroplasticity -- the brain's ability to reorganise itself to compensate for a change or injury.

"We wanted to find out more about how it relates to the likelihood of recovery in patients with smell loss due to viruses."

The research team worked with 143 participants who had experienced a loss or change in their sense of smell due to post viral infection.

The participants received a variety of smell training kits -- consisting of different odours, including eucalyptus, lemon, rose, cinnamon, chocolate, coffee, lavender, honey, strawberry and thyme.

The participants were tested for how well they could smell different odours at the start of the trial, and after six months of smell training.

Prof Philpott said: "We found that the presence of parosmia and worse smell performance on testing of odour identification and discrimination was associated with clinically significant recovery in smell function for people experiencing post-viral smell disorders.

"This means that smell training can help the smell pathways to start to regenerate and recover.

"We also found that older people in particular were more likely to start to recover their sense of smell. And that the biggest improvements happened in those that had lost the most amount of smell function in the first place."

The research was carried out prior to Covid-19, however the researchers say their findings could be helpful to people who have lost their sense of smell as a result of the pandemic.

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How SARS-CoV-2 reaches the brain

 Using post-mortem tissue samples, a team of researchers from Charité -- Universitätsmedizin Berlin have studied the mechanisms by which the novel coronavirus can reach the brains of patients with COVID-19, and how the immune system responds to the virus once it does. The results, which show that SARS-CoV-2 enters the brain via nerve cells in the olfactory mucosa, have been published in Nature Neuroscience*. For the first time, researchers have been able to produce electron microscope images of intact coronavirus particles inside the olfactory mucosa.

It is now recognized that COVID-19 is not a purely respiratory disease. In addition to affecting the lungs, SARS-CoV-2 can impact the cardiovascular system, the gastrointestinal tract and the central nervous system. More than one in three people with COVID-19 report neurological symptoms such as loss of, or change in, their sense of smell or taste, headaches, fatigue, dizziness, and nausea. In some patients, the disease can even result in stroke or other serious conditions. Until now, researchers had suspected that these manifestations must be caused by the virus entering and infecting specific cells in the brain. But how does SARS-CoV-2 get there? Under the joint leadership of Dr. Helena Radbruch of Charité's Department of Neuropathology and the Department's Director, Prof. Dr. Frank Heppner, a multidisciplinary team of researchers has now traced how the virus enters the central nervous system and subsequently invades the brain.

As part of this research, experts from the fields of neuropathology, pathology, forensic medicine, virology and clinical care studied tissue samples from 33 patients (average age 72) who had died at either Charité or the University Medical Center Göttingen after contracting COVID-19. Using the latest technology, the researchers analyzed samples taken from the deceased patients' olfactory mucosa and from four different brain regions. Both the tissue samples and distinct cells were tested for SARS-CoV-2 genetic material and a 'spike protein' which is found on the surface of the virus. The team provided evidence of the virus in different neuroanatomical structures which connect the eyes, mouth and nose with the brain stem. The olfactory mucosa revealed the highest viral load. Using special tissue stains, the researchers were able to produce the first-ever electron microscopy images of intact coronavirus particles within the olfactory mucosa. These were found both inside nerve cells and in the processes extending from nearby supporting (epithelial) cells. All samples used in this type of image-based analysis must be of the highest possible quality. To guarantee this was the case, the researchers ensured that all clinical and pathological processes were closely aligned and supported by a sophisticated infrastructure.

"These data support the notion that SARS-CoV-2 is able to use the olfactory mucosa as a port of entry into the brain," says Prof. Heppner. This is also supported by the close anatomical proximity of mucosal cells, blood vessels and nerve cells in the area. "Once inside the olfactory mucosa, the virus appears to use neuroanatomical connections, such as the olfactory nerve, in order to reach the brain," adds the neuropathologist. "It is important to emphasize, however, that the COVID-19 patients involved in this study had what would be defined as severe disease, belonging to that small group of patients in whom the disease proves fatal. It is not necessarily possible, therefore, to transfer the results of our study to cases with mild or moderate disease."

The manner in which the virus moves on from the nerve cells remains to be fully elucidated. "Our data suggest that the virus moves from nerve cell to nerve cell in order to reach the brain," explains Dr. Radbruch. She adds: "It is likely, however, that the virus is also transported via the blood vessels, as evidence of the virus was also found in the walls of blood vessels in the brain." SARS-CoV-2 is far from the only virus capable of reaching the brain via certain routes. "Other examples include the herpes simplex virus and the rabies virus," explains Dr. Radbruch.

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Not just lizards: Alligators can regrow their tails too, new study reveals

 

American alligator

An interdisciplinary team of scientists using advanced imaging technology have answered the question of whether alligators share any of the same regenerative capabilities as much smaller reptiles. Many kinds of small reptiles, such as lizards, are known to regrow their tails. However, with a potential body length of 14 feet, little was known about whether alligators could possibly regrow their massive tails.

A team of researchers from Arizona State University and the Louisiana Department of Wildlife and Fisheries have uncovered that young alligators have the ability to regrow their tails up to three-quarters of a foot -- about 18% of their total body length. They speculate that regrowing their tails gives the alligators a functional advantage in their murky aquatic habitats.

The team combined advanced imaging techniques with demonstrated methods of studying anatomy and tissue organization to examine the structure of these regrown tails. They found that these new tails were complex structures, with a central skeleton composed of cartilage surrounded by connective tissue that was interlaced with blood vessels and nerves. Their findings are published in the journal Scientific Reports.

"What makes the alligator interesting, apart from its size, is that the regrown tail exhibits signs of both regeneration and wound healing within the same structure," said Cindy Xu, a recent PhD graduate from ASU's School of Life Sciences molecular and cellular biology program and lead author of the paper.

"Regrowth of cartilage, blood vessels, nerves and scales were consistent with previous studies of lizard tail regeneration from our lab and others," she said. "However, we were surprised to discover scar-like connective tissue in place of skeletal muscle in the regrown alligator tail. Future comparative studies will be important to understand why regenerative capacity is variable among different reptile and animal groups."

"The spectrum of regenerative ability across species is fascinating, clearly there is a high cost to producing new muscle," said Jeanne Wilson-Rawls, co-senior author and associate professor with ASU's School of Life Sciences.

Alligators, lizards and humans all belong to a group of animals with backbones called amniotes. In addition to previous studies about the ability of lizards to regrow their tails, the discovery of such large and complex new tails in alligators provides considerable new information about regenerative process in the larger animal classification of amniotes.

This also leads to new questions about the history of these capabilities, and the possibilities for the future.

"The ancestors of alligators and dinosaurs and birds split off around 250 million years ago," said co-senior author Kenro Kusumi, professor and director of ASU's School of Life Sciences and associate dean in The College of Liberal Arts and Sciences.

"Our finding that alligators have retained the cellular machinery to regrow complex tails while birds have lost that ability raises the question of when during evolution this ability was lost. Are there fossils out there of dinosaurs, whose lineage led to modern birds, with regrown tails? We haven't found any evidence of that so far in the published literature."

The researchers hope their findings will help lead to discoveries of new therapeutic approaches to repairing injuries and treating diseases such as arthritis.

"If we understand how different animals are able to repair and regenerate tissues, this knowledge can then be leveraged to develop medical therapies," said Rebecca Fisher, co-author and professor with the University of Arizona College of Medicine-Phoenix and ASU's School of Life Sciences.

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