Sep 22, 2018

Nuclear pasta, the hardest known substance in the universe

A team of scientists has calculated the strength of the material deep inside the crust of neutron stars and found it to be the strongest known material in the universe.

Matthew Caplan, a postdoctoral research fellow at McGill University, and his colleagues from Indiana University and the California Institute of Technology, successfully ran the largest computer simulations ever conducted of neutron star crusts, becoming the first to describe how these break.

"The strength of the neutron star crust, especially the bottom of the crust, is relevant to a large number of astrophysics problems, but isn't well understood," says Caplan.

Neutron stars are born after supernovas, an implosion that compresses an object the size of the sun to about the size of Montreal, making them "a hundred trillion times denser than anything on earth." Their immense gravity makes their outer layers freeze solid, making them similar to earth with a thin crust enveloping a liquid core.

This high density causes the material that makes up a neutron star, known as nuclear pasta, to have a unique structure. Below the crust, competing forces between the protons and neutrons cause them to assemble into shapes such as long cylinders or flat planes, which are known in the literature as 'lasagna' and 'spaghetti,' hence the name 'nuclear pasta.' Together, the enormous densities and strange shapes make nuclear pasta incredibly stiff.

Thanks to their computer simulations, which required 2 million hours worth of processor time or the equivalent of 250 years on a laptop with a single good GPU, Caplan and his colleagues were able to stretch and deform the material deep in the crust of neutron stars.

"Our results are valuable for astronomers who study neutron stars. Their outer layer is the part we actually observe, so we need to understand that in order to interpret astronomical observations of these stars," Caplan adds.

The findings, accepted for publication in Physical Review Letters, could help astrophysicists better understand gravitational waves like those detected last year when two neutron stars collided. Their new results even suggest that lone neutron stars might generate small gravitational waves.

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Astrophysicists measure precise rotation pattern of sun-like stars for the first time

Sun-like stars rotate up to two and a half times faster at the equator than at higher latitudes, a finding by researchers at NYU Abu Dhabi that challenges current science on how stars rotate.

Until now, little was known about the precise rotational patterns of Sun-like stars, only that the equator spins faster than at higher latitudes, similar to the Sun.

Scientists at the NYU Abu Dhabi Center for Space Science used observations from NASA's Kepler mission and asteroseismology -- the study of sound waves traveling inside stars -- to determine with precision how Sun-like stars rotate, which no other scientific method has been able to achieve.

Their study found that Sun-like stars, characterized as being like the Sun in mass and age, do indeed rotate in a similar manner as the Sun in that their equatorial regions rotate more rapidly than at mid- to high latitudes. But there's a key difference.

The equator of the Sun rotates about 10 percent faster than its mid latitudes, while equators of Sun-like stars spin up to two and a half times faster than their mid latitudes.

"This is very unexpected, and challenges current numerical simulations, which suggest that stars like these should not be able to sustain differential rotation of this magnitude," said Othman Benomar, research associate at the NYU Abu Dhabi Center for Space Science and lead author of the study published in Science.

"Understanding differential rotation -- how fast one part of a star spins compared to the rest -- is not only important for a complete understanding of how a star works, it will help us gain deeper insights about their magnetic fields," explained Katepalli Sreenivasan, principal investigator of the NYU Abu Dhabi Center for Space Science.

Magnetic fields on the Sun have been known to cause enormous solar storms that frequently disrupt orbiting space satellites and have knocked out power grids on Earth.

Scientists agree that the rotation of the Sun plays a crucial role in the generation of the solar magnetic field, but the exact details still remain a mystery, despite the Sun having been observed and studied in great detail.

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Sep 21, 2018

Genomic dark matter activity connects Parkinson's and psychiatric diseases

Illustration depicting transcribed noncoding elements (TNE or enhancer RNAs) in the brain
Dopamine neurons are located in the midbrain, but their tendril-like axons can branch far into the higher cortical areas, influencing how we move and how we feel. New genetic evidence has revealed that these specialized cells may also have far-reaching effects, implicating them in conditions that range from Parkinson's disease to schizophrenia. Using a new technique known as laser-capture RNA seq, that involves cutting out dopamine neurons from a human brain section with a laser, investigators from Brigham and Women's Hospital and Harvard Medical School have cataloged more than 70,000 novel elements active in these brain cells. Their results are published this week in Nature Neuroscience.

"We found that a whopping 64 percent of the human genome -- the vast majority of which is 'dark matter' DNA that does not code proteins -- is expressed in dopamine neurons in the human brain," said Clemens Scherzer, MD, a neurologist and genomicist who directs the APDA Center for Advanced Parkinson's Disease Research and leads the Precision Neurology Program at BWH. "These are critical and specialized cells in the human brain, which are working sluggishly in Parkinson's disease, but might be overactive in schizophrenia."

Scherzer's team developed laser-capture RNAseq to precisely dissect out dopamine neurons from the brain and perform ultradeep RNA sequencing on human brain cells. From 86 post-mortem brains, the team was able to extract more than 40,000 dopamine neurons. While other groups have focused on protein-producing messenger RNA, Scherzer and colleagues wanted to catalog the cells' entire RNA content, which required taking a much deeper dive.

In total, they found 71,022 transcribed noncoding elements (so called TNEs). Many of these TNEs (pronounced "teenies") are active enhancers -- sites that act as regulatory "switches" for turning on specialized functions for billions of neurons in the brain. Many of the TNEs the team unearthed are novel and had never before been described in the brain. Working with collaborators in England, Scherzer and colleagues tested several of the TNEs in preclinical models, including zebrafish, finding evidence that many were active in brain development.

Scherzer and first-author Xianjun Dong, PhD, who are also Principal Investigators at the Ann Romney Center at BWH, originally set out to study dopamine neurons to gain insights into Parkinson's but found that many of the genetic variants associated with schizophrenia, addiction and other neuropsychiatric diseases were also enriched in these elements.

"This work suggests that noncoding RNAs active in dopamine neurons are a surprising link between genetic risk, Parkinson's and psychiatric disease," said Scherzer. "Based on this connection we hypothesize that the risk variants might fiddle with the gene switches of dopamine-producing brain cells."

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What makes a mammal a mammal? Our spine, say scientists

Reconstruction of Edaphosaurus, a primitive mammal ancestor; its long spines form a sail on its back.
Mammals are unique in many ways. We're warm-blooded and agile in comparison with our reptilian relatives.

But a new study, funded by the National Science Foundation (NSF) and led by Harvard University researchers Stephanie Pierce and Katrina Jones, suggests we're unique in one more way -- the makeup of our spines. The researchers describe their finding in a paper published this week in the journal Science.

"The spine is basically like a series of beads on a string, with each bead representing a single bone -- a vertebra," said Pierce, curator of vertebrate paleontology at Harvard. "In most four-legged animals, like lizards, the vertebrae all look and function the same.

"But mammal backbones are different. The different sections or regions of the spine -- like the neck, thorax and lower back -- take on very different shapes. They function separately and so can adapt to different ways of life, like running, flying, digging and climbing."

While mammal backbones are specialized, the regions that underlie them were believed to be ancient, dating back to the earliest land animals.

Mammals made the most of the existing anatomical blueprint, or so scientists believed. However, the new study is challenging this idea by looking into the fossil record.

"There are no animals alive today that record the transition from a 'lizard-like' ancestor to a mammal," said Jones, lead author of the study. "To do that, we have to dive into the fossil record and look at the extinct forerunners of mammals, the non-mammalian synapsids."

These ancient ancestors hold the key to understanding the origin of mammal-specific characteristics, including the spine.

But studying fossils isn't easy. "Fossils are scarce and finding extinct animals with all 25-plus vertebrae in place is incredibly rare," Jones said.

To tackle this problem, the researchers combed museum collections around the world to study the best-preserved fossils of animals that lived some 320 million years ago.

"Looking into the ancient past, an early change in mammals' spinal columns was an important first step in their evolution," said Dena Smith, a program director in NSF's Division of Earth Sciences, which funded the research. "Changes in the spine over time allowed mammals to develop into the myriad species we know today."

Pierce and Jones, along with co-author Ken Angielczyk of the Field Museum in Chicago, examined dozens of fossil spines, as well as more than 1,000 vertebrae of living animals, including mice, alligators, lizards and amphibians.

They wanted to find out whether mammal vertebral regions were as ancient as previously thought, or if mammals were doing something unique.

"If vertebral regions had remained unchanged through evolution, as hypothesized, we would expect to see the same regions in the non-mammalian synapsids that we see in mammals today," said Pierce.

But that doesn't seem to be the case. When the researchers compared the positioning and shape of the vertebrae, they found something surprising. The spine had gained new regions during mammal evolution.

"The earliest non-mammalian synapsids had fewer regions than living mammals," said Jones.

About 250 million years ago, a new region evolved near the shoulders and front legs. Dramatic changes also began to appear in the forelimbs of animals known as non-mammalian therapsids.

These simultaneous developments, the scientists believe, likely occurred in conjunction with changes in how creatures walked and ran.

"There appears to be some sort of cross-talk during development between the tissues that form the vertebrae and the shoulder blade," Pierce said. "We think this interaction resulted in the addition of a region near the shoulder as the forelimbs of our ancestors evolved to take on new shapes and functions."

Later, a region emerged near the pelvis. "It is this last region, the ribless lumbar region, that appears to be able to adapt the most to different environments," said Pierce.

The final step in building the mammal backbone may be linked with changes in Hox genes, important to spine regions early in their development.

Read more at Science Daily

Octopuses given mood drug 'ecstasy' reveal genetic link to evolution of social behaviors in humans

By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or 'ecstasy,' scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree.
By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or "ecstasy," scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree.

A summary of the experiments is published Sept. 20 in Current Biology, and if the findings are validated, the researchers say, they may open opportunities for accurately studying the impact of psychiatric drug therapies in many animals distantly related to people.

"The brains of octopuses are more similar to those of snails than humans, but our studies add to evidence that they can exhibit some of the same behaviors that we can," says Gül Dölen, M.D., Ph.D., assistant professor of neuroscience at the Johns Hopkins University School of Medicine and the lead investigator conducting the experiments. "What our studies suggest is that certain brain chemicals, or neurotransmitters, that send signals between neurons required for these social behaviors are evolutionarily conserved."

Octopuses, says Dölen, are well-known to be clever creatures. They can trick prey to come into their clutches, and Dölen says there is some evidence they also learn by observation and have episodic memory. The gelatinous invertebrates (animals without backbones) are further notorious for escaping from their tank, eating other animals' food, eluding caretakers and sneaking around.

But most octopuses are asocial animals and avoid others, including other octopuses. But because of some of their behaviors, Dölen still thought there may be a link between the genetics that guide social behavior in them and humans. One place to look was in the genomics that guide neurotransmitters, the signals that neurons pass between each other to communicate.

Dölen and Eric Edsinger, Ph.D., a research fellow at the Marine Biological Laboratory in Woods Hole, Massachusetts, took a closer look at the genomic sequence of Octopus bimaculoides, commonly referred to as the California two-spot octopus.

Specifically, in the gene regions that control how neurons hook neurotransmitters to their membrane, Dölen and Edsinger found that octopuses and humans had nearly identical genomic codes for the transporter that binds the neurotransmitter serotonin to the neuron's membrane. Serotonin is a well-known regulator of mood and closely linked to certain kinds of depression.

The serotonin-binding transporter is also known to be the place where the drug MDMA binds to brain cells and alters mood. So, the researchers set out to see if and/or how octopuses react to the drug, which also produces so-called pro-social behaviors in humans, mice and other vertebrates.

Dölen designed an experiment with three connected water chambers: one empty, one with a plastic action figure under a cage and one with a female or male laboratory-bred octopus under a cage.

Four male and female octopuses were exposed to MDMA by putting them into a beaker containing a liquefied version of the drug, which is absorbed by the octopuses through their gills. Then, they were placed in the experimental chambers for 30 minutes. All four tended to spend more time in the chamber where a male octopus was caged than the other two chambers.

"It's not just quantitatively more time, but qualitative. They tended to hug the cage and put their mouth parts on the cage," says Dölen. "This is very similar to how humans react to MDMA; they touch each other frequently."

Under normal conditions, without MDMA, five male and female octopuses avoided only male, caged octopuses.

Dölen says the experiments suggest that the brain circuits guiding social behavior in octopuses are present in normal conditions, but may be suppressed by natural or other circumstances. "Octopuses will suspend their antisocial behavior for mating, for example. Then, when they are done mating, they go into aggressive, asocial mode," says Dolen.

Read more at Science Daily

Fat from 558 million years ago reveals earliest known animal

This is a Dickinsonia fossil.
Scientists from The Australian National University (ANU) and overseas have discovered molecules of fat in an ancient fossil to reveal the earliest confirmed animal in the geological record that lived on Earth 558 million years ago.

The strange creature called Dickinsonia, which grew up to 1.4 metres in length and was oval shaped with rib-like segments running along its body, was part of the Ediacara Biota that lived on Earth 20 million years prior to the 'Cambrian explosion' of modern animal life.

ANU PhD scholar Ilya Bobrovskiy discovered a Dickinsonia fossil so well preserved in a remote area near the White Sea in the northwest of Russia that the tissue still contained molecules of cholesterol, a type of fat that is the hallmark of animal life.

Lead senior researcher Associate Professor Jochen Brocks said the 'Cambrian explosion' was when complex animals and other macroscopic organisms -- such as molluscs, worms, arthropods and sponges -- began to dominate the fossil record.

"The fossil fat molecules that we've found prove that animals were large and abundant 558 million years ago, millions of years earlier than previously thought," said Associate Professor Jochen Brocks from the ANU Research School of Earth Sciences.

"Scientists have been fighting for more than 75 years over what Dickinsonia and other bizarre fossils of the Edicaran Biota were: giant single-celled amoeba, lichen, failed experiments of evolution or the earliest animals on Earth. The fossil fat now confirms Dickinsonia as the oldest known animal fossil, solving a decades-old mystery that has been the Holy Grail of palaeontology."

Mr Bobrovskiy said the team developed a new approach to study Dickinsonia fossils, which hold the key between the old world dominated by bacteria and the world of large animals that emerged 540 million years ago during the 'Cambrian explosion'.

"The problem that we had to overcome was finding Dickinsonia fossils that retained some organic matter," said Mr Bobrovskiy from the ANU Research School of Earth Sciences.

"Most rocks containing these fossils such as those from the Ediacara Hills in Australia have endured a lot of heat, a lot of pressure, and then they were weathered after that -- these are the rocks that palaeontologists studied for many decades, which explained why they were stuck on the question of Dickinsonia's true identity."

Palaeontologists normally study the structure of fossils, but Mr Bobrovskiy extracted and analysed molecules from inside the Dickinsonia fossil found in ancient rocks in Russia to make the breakthrough discovery.

"I took a helicopter to reach this very remote part of the world -- home to bears and mosquitoes -- where I could find Dickinsonia fossils with organic matter still intact," Mr Bobrovskiy said.

"These fossils were located in the middle of cliffs of the White Sea that are 60 to 100 metres high. I had to hang over the edge of a cliff on ropes and dig out huge blocks of sandstone, throw them down, wash the sandstone and repeat this process until I found the fossils I was after."

Associate Professor Brocks said being able to study molecules from these ancient organisms was a gamechanger.

"When Ilya showed me the results, I just couldn't believe it," he said.

Read more at Science Daily

Sep 20, 2018

Basking sharks can jump as high and as fast as great whites

This is a breaching basking shark.
A collaborative team of marine biologists has discovered that basking sharks, hundreds of which are found off the shores of Ireland, Cornwall, the Isle of Man and Scotland, can jump as fast and as high out of the water as their cousins, the famously powerful and predatory great white shark.

Basking sharks are the second largest fish in the world, reaching lengths of up to 10m (33ft). Until now, they have previously had a reputation for being slow and languid as they scour the sea for their staple diet of plankton.

However, a new study, recently published in leading international journal Biology Letters used video analysis for both species and estimated their vertical swimming speeds at the moment at which they left the water. Furthermore, they attached a data recording device to one large basking shark to measure its speed and movement, and also to store video footage.

At one point, in just over nine seconds, and with 10 beats of its tail, the basking shark accelerated from a depth of 28 m to the surface and broke through the water at nearly 90 degrees. The shark cleared the water for one second, and its leap peaked at a height of 1.2 m above the surface.

To achieve this breach, the basking shark exhibited a six-fold increase in tail beat frequency and attained a top speed of approximately 5.1 m/s. To put this into perspective, this is more than twice as fast as the average competitor in the Olympic men's 50m freestyle swim.

The videos from boats and the land of both basking sharks and great whites breaching showed similar speeds of breaching in other individuals. The basking shark videos were recorded in 2015 at Malin Head, Ireland, while the great white shark videos were recorded in 2009 at two sites in South Africa, where seal-shaped decoys induced feeding attempts.

Assistant Professor in Zoology at Trinity College Dublin, Dr Nick Payne, was a co-author of the journal article. He said: "The impressive turn of speed that we found basking sharks exhibit shows how much we are yet to learn about marine animals -- even the largest, most conspicuous species have surprises in store, if we're willing to look."

Read more at Science Daily

Southeast Asian population boomed 4,000 years ago

Clare McFadden.
Researchers at The Australian National University (ANU) have uncovered a previously unconfirmed population boom across South East Asia that occurred 4,000 years ago, thanks to a new method for measuring prehistoric population growth.

Using the new population measurement method, which utilises human skeletal remains, they have been able to prove a significant rapid increase in growth across populations in Thailand, China and Vietnam during the Neolithic Period, and a second subsequent rise in the Iron Age.

Lead researcher Clare McFadden, a PhD Scholar with the ANU School of Archaeology and Anthropology, said the population trend was consistent across samples taken from 15 locations.

"We saw huge population growth associated with the agricultural transition," McFadden said.

"Up until about 4,000 years ago you have hunter gatherer type populations, then you have the introduction and intensification of agriculture.

"Agricultural transition has been widely studied around the world and we consistently see significant population growth as a result."

The reason these population changes have never been quantified before is the tools used to measure prehistoric populations were all designed for Europe and the Americas where archaeological conditions are different to Asia.

Ms McFadden said the difference comes down to how children are represented in population numbers.

"For skeletal remains in Europe and America we often see the complete absence of infants and children, they are very poorly represented," she said.

"The preservation isn't good -- small bones don't preserve well. Children are also thought to often be buried in a different cemetery to adults.

"So the method researchers used to measure populations excluded children because they didn't have accurate representation."

Ms McFadden said her new method for determining the rate of natural population increase takes into account the proportion of infants and children compared to the total population. This way researchers were able to bring population growth figures in line with other archaeological evidence in the region which suggested a rapid rise.

"In South East Asia and the Pacific, we actually have pretty good preservation of bones from children," she said.

"The skeletal evidence was there, we were seeing populations with huge numbers of infants and children compared to the adult populations, which suggests it was a growing population at that time. But the existing tools weren't detecting that growth.

Read more at Science Daily

Cane toad: Scientists crack genetic code

Cane toad, Rhinella marina
A group of scientists from UNSW Sydney, the University of Sydney, Deakin University, Portugal and Brazil have unlocked the DNA of the cane toad, a poisonous amphibian that is a threat to many native Australian species. The findings were published in academic journal GigaScience today.

"Despite its iconic status, there are major gaps in our understanding of cane toad genetics, and up until now, no one had put the genome together," says Peter White, project leader and Professor in Microbiology and Molecular Biology at UNSW.

A decade ago, researchers in WA had already tried to sequence the cane toad genome, but they encountered obstacles when it came to assembling it, and didn't complete the project.

For this project, the UNSW-University of Sydney team worked at the Ramaciotti Centre for Genomics at UNSW, which has played a role in decoding the genomes of other iconic Australian species, including the koala.

"Sequencing and assembling a genome is a complicated process. By using the cutting-edge sequencing technology and expertise available at UNSW, we sequenced 360-odd billion base pairs and assembled one of the best quality amphibian genomes to date," says Senior Lecturer Dr Rich Edwards, lead author of the study.

"We managed to decipher more than 90% of the cane toad genes using technology that can sequence very long pieces of DNA, which makes the task of putting together the genome jigsaw much easier."

Having a draft cane toad genome will help to close key knowledge gaps and accelerate cane toad research. More toads can now be sequenced at a fraction of the cost, and the genome is freely available -- anyone can access it now and conduct further research.

"Future analysis of the genome will provide insights into cane toad evolution and enrich our understanding of their interplay with the ecosystem at large -- it will help us understand how the toad spreads, how its toxin works, and provide new avenues to try to control its population," says cane toad expert and Emeritus Professor Rick Shine from the University of Sydney.

"Very few amphibian genomes have been sequenced to date, so this is also great news for amphibians. Having a reference genome could provide valuable insights into how invasive species evolve to adapt to new environments."

Having the genome will also help researchers to find new options for controlling the toad population.

"Current measures like physical removal haven't been successful, but new methods to teach native species not to eat the toad -- called taste aversion -- give new hope. However, we need more approaches to control this invasive species," Professor White says.

For one such alternative measure -- biocontrol, i.e. using a virus to help control the toad population -- the toad's genetic material is essential.

"To find a virus for biocontrol, we need access to the toad's DNA and RNA," explains Alice Russo, a PhD student at UNSW who specialises on finding potential viruses to control the toad.

"DNA contains ancient fragments of viruses -- the DNA of every animal can sometimes catalogue past infections."

Viruses have previously been successfully used to control the European rabbit population. The issue with cane toad viruses studied so far was that they could potentially infect native amphibians -- which is why this study aimed to find a cane toad-specific virus.

In a paper published this month in the Journal of Virology, the researchers describe how they sampled cane toads from different Australian locations, and, using a combination of DNA and RNA sequencing, found three new viruses.

"Up until we published this paper, only one family of viruses was known to affect the cane toad. This is the first paper that has found different viruses, which is very promising," Russo says.

"This paper has opened the door: we found a retrovirus, a picornavirus and a circovirus which are genetically similar to viruses infecting frogs, reptiles and fish. For two of them, we found a full genome -- both could potentially be used as biocontrol agents."

Knowing these new viral sequences will help inform future studies which will investigate their prevalence and potential as agents for biocontrol.

"There's a lot more work to be done. However, these two papers are the first -- but most important -- steps in finding an effective way to control the cane toad," Professor White concludes.

Read more at Science Daily

Matter falling into a black hole at 30 percent of the speed of light

This is the characteristic disc structure from the simulation of a misaligned disc around a spinning black hole.
A UK team of astronomers report the first detection of matter falling into a black hole at 30% of the speed of light, located in the centre of the billion-light year distant galaxy PG211+143. The team, led by Professor Ken Pounds of the University of Leicester, used data from the European Space Agency's X-ray observatory XMM-Newton to observe the black hole. Their results appear in a new paper in Monthly Notices of the Royal Astronomical Society.

Black holes are objects with such strong gravitational fields that not even light travels quickly enough to escape their grasp, hence the description 'black'. They are hugely important in astronomy because they offer the most efficient way of extracting energy from matter. As a direct result, gas in-fall -- accretion -- onto black holes must be powering the most energetic phenomena in the Universe.

The centre of almost every galaxy -- like our own Milky Way -- contains a so-called supermassive black hole, with masses of millions to billions of times the mass of our Sun. With sufficient matter falling into the hole, these can become extremely luminous, and are seen as a quasar or active galactic nucleus (AGN).

However black holes are so compact that gas is almost always rotating too much to fall in directly. Instead it orbits the hole, approaching gradually through an accretion disc -- a sequence of circular orbits of decreasing size. As gas spirals inwards, it moves faster and faster and becomes hot and luminous, turning gravitational energy into the radiation that astronomers observe.

The orbit of the gas around the black hole is often assumed to be aligned with the rotation of the black hole, but there is no compelling reason for this to be the case. In fact, the reason we have summer and winter is that the Earth's daily rotation does not line up with its yearly orbit around the Sun.

Until now it has been unclear how misaligned rotation might affect the in-fall of gas. This is particularly relevant to the feeding of supermassive black holes since matter (interstellar gas clouds or even isolated stars) can fall in from any direction.

Using data from XMM-Newton, Prof. Pounds and his collaborators looked at X-ray spectra (where X-rays are dispersed by wavelength) from the galaxy PG211+143. This object lies more than one billion light years away in the direction of the constellation Coma Berenices, and is a Seyfert galaxy, characterised by a very bright AGN resulting from the presence of the massive black hole at its nucleus.

The researchers found the spectra to be strongly red-shifted, showing the observed matter to be falling into the black hole at the enormous speed of 30 per cent of the speed of light, or around 100,000 kilometres per second. The gas has almost no rotation around the hole, and is detected extremely close to it in astronomical terms, at a distance of only 20 times the hole's size (its event horizon, the boundary of the region where escape is no longer possible).

The observation agrees closely with recent theoretical work, also at Leicester and using the UK's Dirac supercomputer facility simulating the 'tearing' of misaligned accretion discs. This work has shown that rings of gas can break off and collide with each other, cancelling out their rotation and leaving gas to fall directly towards the black hole.

Prof. Pounds, from the University of Leicester's Department of Physics and Astronomy, said: "The galaxy we were observing with XMM-Newton has a 40 million solar mass black hole which is very bright and evidently well fed. Indeed some 15 years ago we detected a powerful wind indicating the hole was being over-fed. While such winds are now found in many active galaxies, PG1211+143 has now yielded another 'first', with the detection of matter plunging directly into the hole itself."

He continues: "We were able to follow an Earth-sized clump of matter for about a day, as it was pulled towards the black hole, accelerating to a third of the velocity of light before being swallowed up by the hole."

Read more at Science Daily

Sep 19, 2018

Moderate warming could melt East Antarctic Ice Sheet

These are researchers at dusk on the research vessel JOIDES Resolution, on expedition to Antarctica.
Parts of the world's largest ice sheet would melt if Antarctic warming of just 2°C is sustained for millennia, according to international research.

University of Queensland scientist Dr Kevin Welsh was part of a team that used evidence from warm periods in Earth's history to see how the East Antarctic Ice Sheet might react to a warming climate.

Dr Welsh said marine sediment layers indicated the ice sheet had retreated during warming in the late Pleistocene period, when temperatures were like those predicted for this century.

"Antarctica is around twice the size of Australia, with ice sheets several kilometres thick and containing around half of the world's fresh water," he said.

"The East Antarctic Ice Sheet covers about two thirds of the area, and because its base is largely above sea level it was generally thought to be less sensitive to warming climates than the adjacent West Antarctic Ice Sheet.

"However, some areas -- like the Wilkes Land Subglacial Basin, directly south of Australia -- are below sea level and contain enough ice to raise global sea levels by several metres.

"The evidence we have suggests that with the predicted 2°C warming in Antarctica -- if sustained over a couple of millennia -- the sheet would start melting in these locations."

Dr Welsh, from UQ's School of Earth and Environmental Sciences, said the team chemically analysed layers of sediment deposited on the Southern Ocean floor by glaciers.

"We found that the most extreme changes in the ice sheet occurred during two interglacial periods 125,000 and 400,000 years ago, when global sea levels were several metres higher than they are today," he said.

"These periods could be analogues for future climates and it seems likely that ice loss from the East Antarctic Ice Sheet contributed to those higher sea levels.

"Ice loss contributes to rising global sea levels which are a threat to many coastal communities, and making projections requires a solid understanding of how sensitive these ice sheets are."

Imperial College London researcher Dr David Wilson said the findings were extremely concerning for humanity.

Read more at Science Daily

Oldest-known aquatic reptiles probably spent time on land

This is a drawing of Mesosaurus.
The oldest known aquatic reptiles, the mesosaurs, probably spent part of their life on land, reveals a new study published in Frontiers in Ecology and Evolution. The fossilized bones of adult Mesosaurus share similarities with land-dwelling animals, which -- coupled with the relative scarcity of land-weathered fossilized remains of large specimens -- suggests that older mesosaurs were semi-aquatic, whereas juveniles spent most of their time in the water. This new research emphasizes the importance of thoroughly analyzing fossilized remains from across all stages of a reptile's life to get a full appreciation of its lifestyle and behavior.

"Despite being considered the oldest-known fully aquatic reptile, mesosaurs share several anatomical features with terrestrial species," says Professor Graciela Piñeiro, who completed this research at the Facultad de Ciencias, Universidad de la República, Uruguay. "Our comprehensive analysis of the vertebrae and limbs of these ancient reptiles suggests they lived in the water during the earliest stages of their development, whereas mature adults spent more time on land."

Since the discovery of unusually large Mesosaurus bones in the Mangrullo Formation of Uruguay, Piñeiro and her international team of colleagues wondered why the larger, presumably adult specimens, around two meters in length, were not as abundant as mesosaur skeletons of around 90 cm.

"The larger specimens, at least twice the length of the more commonly reported Mesosaurus fossils, could just be exceptionally big individuals. However, the environmental conditions of the Mangrullo lagoon of where they lived were harsh, making it difficult for the occasional mesosaur to reach such a relatively large size and age," explains Piñeiro.

She continues, "We then realized that in comparison to the smaller, better-preserved specimens, larger Mesosaurus fossils were almost always disarticulated, very weathered and badly preserved. This suggested these larger specimens had extended exposure to the air when they died."

During the reconstruction of a Mesosaurus skeleton and analysis of skeletons representing different life stages of this ancient reptile, the researchers examined the remains for evidence of a terrestrial, land-dwelling existence.

Terrestrial, semi-aquatic and aquatic animals show a clear difference in bone profiles, so they used morphometrics to analyze the shape of the fossilized bones. Forty Mesosaurus specimens, from juveniles to adults, were examined and their bone profiles compared to those of similar reptiles known to be aquatic or semi-aquatic, such as crocodiles and marine iguanas.

"The adult mesosaur tarsus (a cluster of bones in the ankle region) suggests a more terrestrial or amphibious locomotion rather than a fully aquatic behavior as widely suggested before," says Pablo Núñez, also based at Universidad de la República. "Their caudal vertebrae, the tail bones, also showed similarities to semi-aquatic and terrestrial animals. This supports the hypothesis that the oldest and largest mesosaurs spent more time on land, where fossil preservation is not as good as in the subaquatic domain."

Published as part of a special article collection on Mesosaurs, these findings have broader implications -- both for future research on early prehistoric animals that laid eggs with embryonic membranes and for the understanding of reptile evolution.

Piñeiro explains, "Our study emphasizes the importance of working with fossils representing an entire population of a species, including a wide range of juveniles and adults, before establishing paleobiological interpretations on their lifestyle and behavior."

Read more at Science Daily

Looking back in time to watch for a different kind of black hole

Image from the DCBH simulation shows density (left) and temperature (right) of an early galaxy. Supernovae shock waves can be seen expanding from the center, disrupting and heating the galaxy.
Black holes form when stars die, allowing the matter in them to collapse into an extremely dense object from which not even light can escape. Astronomers theorize that massive black holes could also form at the birth of a galaxy, but so far nobody has been able to look far enough back in time to observe the conditions creating these direct collapse black holes (DCBH).

The James Webb Space Telescope, scheduled for launch in 2021, might be able look far enough back into the early Universe to see a galaxy hosting a nascent massive black hole. Now, a simulation done by researchers at the Georgia Institute of Technology has suggested what astronomers should look for if they search the skies for a DCBH in its early stages.

The first-of-its-kind simulation, reported September 10 in the journal Nature Astronomy, suggests that direct formation of these black holes would be accompanied by specific kinds of intense radiation, including X-rays and ultraviolet emission that would shift to infrared by the time they reach the telescope. The black holes would also likely spawn massive metal-free stars, a finding that was unexpected.

The research was supported by NASA, the Los Alamos National Laboratory, the National Science Foundation, the Southern Regional Education Board and two Hubble theory grants.

"There are supermassive black holes at the center of many large galaxies, but we haven't been able to observe the way they form or how they got that large," said Kirk S. S. Barrow, the paper's first author and a recent Ph.D. graduate of Georgia Tech's School of Physics. "Scientists have theorized that these supermassive black holes could have formed at the birth of a galaxy, and we wanted to turn these theoretical predictions into observational predictions that could be seen by the James Webb Space Telescope."

DCBH formation would be initiated by the collapse of a large cloud of gas during the early formation of a galaxy, said John H. Wise, a professor in Georgia Tech's School of Physics and the Center for Relativistic Astrophysics. But before astronomers could hope to catch this formation, they would have to know what to look for in the spectra that the telescope could detect, which is principally infrared.

The formation of a black hole could require a million years or so, but to envision what that might have looked like, former postdoctoral researcher Aycin Aykutalp -- now at Los Alamos National Laboratory -- used the National Science Foundation-supported Stampede Supercomputer at the University of Texas at Austin to run a simulation focusing on the aftermath of DCBH formation. The simulation used physics first principles such as gravity, radiation and hydrodynamics.

"If the galaxy forms first and then the black hole forms in the center, that would have one type of signature," said Wise. "If the black hole formed first, would that have a different signature? We wanted to find out whether there would be any physical differences, and if so, whether that would translate into differences we could observe with the James Webb Space Telescope."

The simulations provided information such as densities and temperatures, and Barrow converted that data into predictions for what might be observed through the telescope -- the light likely to be observed and how it would affected by gas and dust it would have encountered on its long journey to Earth. "At the end, we had something that an observer could hopefully see," Barrow said.

Black holes take about a million years to form, a blip in galactic time. In the DCBH simulation, that first step involves gas collapsing into a supermassive star as much as 100,000 times more massive than our sun. The star then undergoes gravitational instability and collapses into itself to form a massive black hole. Radiation from the black hole then triggers the formation of stars over period of about 500,000 years, the simulation suggested.

"The stars of this first generation are usually much more massive, so they live for a shorter period of time," Wise said. "In the first five to six million years after their formation, they die and go supernova. That's another one of the signatures that we report in this study."

After the supernovae form, the black hole quiets down but creates a struggle between electromagnetic emissions -- ultraviolet light and X-rays trying to escape -- and the black hole's own gravity. "These cycles go on for another 20 or 30 million years," Wise said.

Black holes are relatively common in the universe, so the hope is that with enough snapshots, astronomers could catch one being born, and that could lead to a new understanding of how galaxies evolve over time.

Star formation around the DCBH was unexpected, but in hindsight, it makes sense, Barrow said. The ionization produced by the black holes would produce photochemical reactions able to trigger the formation of the stars. Metal-free stars tend to be larger than others because the absence of a metal such as iron prevents fragmentation. But because they are so large, these stars produce tremendous amounts of radiation and end their lives in supernovae, he said.

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Gaia hints at our Galaxy’s turbulent life

ESA's star mapping mission, Gaia, has shown our Milky Way galaxy is still enduring the effects of a near collision that set millions of stars moving like ripples on a pond.

The close encounter likely took place sometime in the past 300-900 million years. It was discovered because of the pattern of movement it has given to stars in the Milky Way disc -- one of the major components of our Galaxy.

The pattern was revealed because Gaia not only accurately measures the positions of more than a billion stars but also precisely measures their velocities on the plane of the sky. For a subset of a few million stars, Gaia provided an estimate of the full three-dimensional velocities, allowing a study of stellar motion using the combination of position and velocity, which is known as 'phase space'.

In phase space, the stellar motions revealed an interesting and totally unexpected pattern when the star's positions were plotted against their velocities. Teresa Antoja from Universitat de Barcelona, Spain, who led the research couldn't quite believe her eyes when she first saw it on her computer screen.

One shape in particular caught her attention. It was a snail shell-like pattern in the graph that plotted the stars' altitude above or below the plane of the Galaxy against their velocity in the same direction. It had never been seen before.

"At the beginning the features were very weird to us," says Teresa. "I was a bit shocked and I thought there could be a problem with the data because the shapes are so clear."

But the Gaia data had undergone multiple validation tests by the Gaia Data Processing and Analysis Consortium teams all over Europe before release. Also, together with collaborators, Teresa had performed many tests on the data to look for errors that could be forcing such shapes on the data. Yet no matter what they checked, the only conclusion they could draw was that these features do indeed exist in reality.

The reason they had not been seen before was because the quality of the Gaia data was a huge step up from what had come before.

"It looks like suddenly you have put the right glasses on and you see all the things that were not possible to see before," says Teresa.

With the reality of the structure confirmed, it came time to investigate why it was there.

"It is a bit like throwing a stone in a pond, which displaces the water as ripples and waves," explains Teresa.

Unlike the water molecules, which settle again, the stars retain a 'memory' that they were perturbed. This memory is found in their motions. After some time, although the ripples may no longer be easily visible in the distribution of stars, they are still there when you look in their velocities.

The researchers looked up previous studies that had investigated such 'phase mixing' in other astrophysical settings and in quantum physics situations. Although no one had investigated this happening in the disc of our Galaxy, the structures were clearly reminiscent of each other.

"I find this really amazing that we can see this snail shell shape. It is just like it appears in text books," says Amina Helmi, University of Groningen, The Netherlands, a collaborator on the project and the second author on the resulting paper.

So the next question was what had 'hit' the Milky Way to cause this behaviour in the stars. We know that our Galaxy is a cannibal. It grows by eating smaller galaxies and clusters of stars that then mix in with the rest of the Galaxy. But that didn't seem to be the case here.

Then Amina recalled her own and others studies of the Sagittarius dwarf galaxy. This small galaxy contains a few tens of millions of stars and is currently in the process of being cannibalised by the Milky Way.

Its last close pass to our Galaxy was not a direct hit -- it passed close by. This would have been enough so that its gravity perturbed some stars in our Galaxy like a stone dropping into water.

The clincher was that estimates of Sagittarius's last close encounter with the Milky Way place it sometime between 200 and 1000 million years ago, which is almost exactly what Teresa and colleagues calculated as an origin for the beginning of the snail shell-like pattern.

So far, however, the association of the snail shell feature with the Sagittarius dwarf galaxy is based on simple computer models and analyses. The next step is to scrutinise the phenomenon more fully to gain knowledge of the Milky Way.

The scientists plan to investigate this galactic encounter as well as the distribution of matter in the Milky Way by using the information contained in the snail shell shape. One thing is certain. There is a lot of work to do.

"The discovery was easy; the interpretations harder. And the full understanding of its meaning and implications might take several years." said Amina.

Gaia is one of ESA's cornerstone missions and was designed primarily to investigate the origin, evolution and structure of the Milky Way. In April, it made available its second data release, which is the data that made this discovery possible.

Read more at Science Daily

Sep 18, 2018

Do we trust people who speak with an accent?

You are in a strange neighbourhood, your cell phone's dead, and you desperately need to find the closest garage. A couple of people on the street chime in, each sending you in opposite directions. One person sounds like a local and speaks in a nonchalant manner, while the other uses a loud, confident voice but speaks with a strong accent. Who are you going to trust? A recently published study shows that unless they speak in a confident tone of voice, you're less likely to believe someone who speaks with an accent. And, interestingly, as you make this decision different parts of your brain are activated, depending on whether you perceive the speaker to be from your own "in-group" or from some type of "out-group" (e.g., someone with a different linguistic or cultural background).

Marc Pell, from McGill's School of Communication Sciences and Disorders, the senior author explains the rationale for the study:

"There are possibly two billion people around the world who speak English as a second language -- and many of us live in societies that are culturally diverse. As we make decisions about whether or not to trust people who are different from us we pay a lot of attention both to visual cues and to a person's voice. Here, we wanted to better understand how we make trust-related decisions about other people based strictly on their speaking voice."

Overall, the researchers found that making trust-related decisions about accented speakers is more difficult due to our underlying bias favouring members of our own group. They also discovered that different regions of the brain are activated to analyze whether to believe speech from "in-group" and "out-group" members. Indeed, the brain needed to engage in additional processes to resolve the conflict between our negative bias towards the accent (don't believe!) and the impression that the speaker is very sure of what they're saying (it must be true!).

Confidence speaks volumes
Interestingly, what the researchers discovered was that when speakers with a regional or foreign accent use a very confident voice, their statements are judged to be equally believable to native speakers of the language.

"What this shows me is that, in future, if I want to be believed, it may be in my interest to adopt a very confident tone of voice in a whole range of situations," says Xiaoming Jiang, a former post-doctoral fellow at McGill and now Associate Professor at Tongji University, who speaks English as a second-language and is the first author on the paper. "This is a finding that potentially has repercussions for people who speak with an accent when it comes to everything ranging from employment to education and the judicial process."

Different accents mean different brain activation

Earlier research has shown that people are more likely to believe statements produced in a confident tone (voiced in a way that is louder, lower in pitch, and faster) than those spoken in a hesitant manner. The researchers wanted to see whether the same areas of the brain were activated as we made trust-related decisions about statements made in an accent that is different from our own.

When making decisions about whether to trust a speaker who has the same accent as us, the researchers discovered that the listeners could focus simply on tone of voice. The areas of the brain that were activated were those involved in making inferences based on past experience (the superior parietal regions). Whereas, when it came to making similar decisions for "out-group" speakers, the areas of the brain involved in auditory processing (the temporal regions of the brain) were involved to a greater extent. This suggests that as listeners made decisions about whether to trust accented speakers they needed to engage in a two-step process where they needed to pay attention both to the sounds that an accented speaker was producing as well as to their tone of voice.

Read more at Science Daily

Magellanic Clouds duo may have been a trio

The large and small Magellanic Clouds.
Two of the closest galaxies to the Milky Way -- the Large and Small Magellanic Clouds -- may have had a third companion, astronomers believe.

Research published today describes how another "luminous" galaxy was likely engulfed by the Large Magellanic Cloud some three to five billion years ago.

ICRAR Masters student Benjamin Armstrong, the lead author on the study, said most stars in the Large Magellanic Cloud rotate clockwise around the centre of the galaxy.

But, unusually, some stars rotate anti-clockwise.

"For a while, it was thought that these stars might have come from its companion galaxy, the Small Magellanic Cloud," Mr Armstrong said.

"Our idea was that these stars might have come from a merger with another galaxy in the past."

Mr Armstrong, who is based at The University of Western Australia, used computer modelling to simulate galaxy mergers.

"What we found is that in this sort of merging event, you actually can get quite strong counter-rotation after a merger takes place," he said.

"This is consistent with what we see when we actually observe the galaxies."

The Magellanic Clouds can be seen in the night sky with the naked eye and have been observed by ancient cultures for thousands of years.

The Large Magellanic Cloud is a relatively small 160,000 light years away from us, while the Small Magellanic Cloud is around 200,000 light years away.

Mr Armstrong said the finding could help to explain a problem that has perplexed astronomers for years -- why stars in the Large Magellanic Cloud are generally either very old or very young.

"In galaxies, there are these large objects called star clusters," he said.

"Star clusters contain many, many, many stars that are all of quite similar ages and made in similar environments.

"In the Milky Way, the star clusters are all very old.

"But in the Large Magellanic Cloud, we have very old clusters as well as ones that are very young -- but nothing in between."

This is known as the 'age-gap' problem, Mr Armstrong said.

"Because in the Large Magellanic Cloud we see star formation starting again, that could be indicative of a galaxy merger taking place," he said.

Mr Armstrong said the finding could also help explain why the Large Magellanic Cloud appears to have a thick disk.

"Our work is still very preliminary but it does suggest that this sort of process could have been responsible for the thicker disk in the past," he said.

Mr Armstrong said the research was about asking pertinent questions that astronomers could start examining.

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Hardwired for laziness? Tests show the human brain must work hard to avoid sloth

The researchers asked volunteers to react to simple stick drawings depicting scenes of physical inactivity and physical activity, and discovered that brain activity differed depending on the scene.
If getting to the gym seems like a struggle, a University of British Columbia researcher wants you to know this: the struggle is real, and it's happening inside your brain.

The brain is where Matthieu Boisgontier and his colleagues went looking for answers to what they call the "exercise paradox": for decades, society has encouraged people to be more physically active, yet statistics show that despite our best intentions, we are actually becoming less active.

The research findings, published recently in Neuropsychologia, suggest that our brains may simply be wired to prefer lying on the couch.

"Conserving energy has been essential for humans' survival, as it allowed us to be more efficient in searching for food and shelter, competing for sexual partners, and avoiding predators," said Boisgontier, a postdoctoral researcher in UBC's brain behaviour lab at the department of physical therapy, and senior author of the study. "The failure of public policies to counteract the pandemic of physical inactivity may be due to brain processes that have been developed and reinforced across evolution."

For the study, the researchers recruited young adults, sat them in front of a computer, and gave them control of an on-screen avatar. They then flashed small images, one a time, that depicted either physical activity or physical inactivity. Subjects had to move the avatar as quickly as possible toward the pictures of physical activity and away from the pictures of physical inactivity -- and then vice versa.

Meanwhile, electrodes recorded what was happening in their brains. Participants were generally faster at moving toward active pictures and away from lazy pictures, but brain-activity readouts called electroencephalograms showed that doing the latter required their brains to work harder.

"We knew from previous studies that people are faster at avoiding sedentary behaviours and moving toward active behaviours. The exciting novelty of our study is that it shows this faster avoidance of physical inactivity comes at a cost -- and that is an increased involvement of brain resources," Boisgontier said. "These results suggest that our brain is innately attracted to sedentary behaviours."

The question now becomes whether people's brains can be re-trained.

"Anything that happens automatically is difficult to inhibit, even if you want to, because you don't know that it is happening. But knowing that it is happening is an important first step," Boisgontier said.

Read more at Science Daily

Transparent loudspeakers and MICs that let your skin play music

Their ultrathin, conductive, and transparent hybrid NMs can be applied to the fabrication of skin-attachable NM loudspeakers and voice-recognition microphones, which would be unobtrusive in appearance due to their excellent transparency and conformal contact capability.
An international team of researchers, affiliated with UNIST has presented an innovative wearable technology that will turn your skin into a loudspeaker.

This breakthrough has been led by Professor Hyunhyub Ko in the School of Energy and Chemical Engineering at UNIST. Created in part to help the hearing and speech impaired, the new technology can be further explored for various potential applications, such as wearable IoT sensors and conformal health care devices.

In the study, the research team has developed ultrathin, transparent, and conductive hybrid nanomembranes with nanoscale thickness, consisting of an orthogonal silver nanowire array embedded in a polymer matrix. They, then, demonstrated their nanomembrane by making it into a loudspeaker that can be attached to almost anything to produce sounds. The researchers also introduced a similar device, acting as a microphone, which can be connected to smartphones and computers to unlock voice-activated security systems.

Nanomembranes (NMs) are molcularly thin seperation layers with nanoscale thickness. Polymer NMs have attracted considerable attention owing to their outstanding advantages, such as extreme flexibility, ultralight weight, and excellent adhesibility in that they can be attached directly to almost any surface. However, they tear easily and exhibit no electrical conductivity.

The research team has solved such issues by embedding a silver nanowire network within a polymer-based nanomembrane. This has enabled the demonstration of skin-attachable and imperceptible loudspeaker and microphone.

"Our ultrathin, transparent, and conductive hybrid NMs facilitate conformal contact with curvilinear and dynamic surfaces without any cracking or rupture," says Saewon Kang in the doctroral program of Energy and Chemical Engineering at UNIST, the first author of the study.

He adds, "These layers are capable of detecting sounds and vocal vibrations produced by the triboelectric voltage signals corresponding to sounds, which could be further explored for various potential applications, such as sound input/output devices."

Using the hybrid NMs, the research team fabricated skin-attachable NM loudspeakers and microphones, which would be unobtrusive in appearance because of their excellent transparency and conformal contact capability. These wearable speakers and microphones are paper-thin, yet still capable of conducting sound signals.

"The biggest breakthrough of our research is the development of ultrathin, transparent, and conductive hybrid nanomembranes with nanoscale thickness, less than 100 nanometers," says Professor Ko. "These outstanding optical, electrical, and mechanical properties of nanomembranes enable the demonstration of skin-attachable and imperceptible loudspeaker and microphone."

The skin-attachable NM loudspeakers work by emitting thermoacoustic sound by the temperature-induced oscillation of the surrounding air. The periodic Joule heating that occurs when an electric current passes through a conductor and produces heat leads to these temperature oscillations. It has attracted considerable attention for being a stretchable, transparent, and skin-attachable loudspeaker.

Wearable microphones are sensors, attached to a speaker's neck to even sense the vibration of the vocal folds. This sensor operates by converting the frictional force generated by the oscillation of the transparent conductive nanofiber into electric energy. For the operation of the microphone, the hybrid nanomembrane is inserted between elastic films with tiny patterns to precisely detect the sound and the vibration of the vocal cords based on a triboelectric voltage that results from the contact with the elastic films.

Read more at Science Daily

Sep 17, 2018

Soil holds the secret to mitigating climate change

Food production doesn't have to be a victim of climate change. New research from Michigan State University suggests that crop yields and the global food supply chain can be preserved by harnessing the critical, and often overlooked, partner in food supply -- soil.

The research, led by MSU Foundation Professor Bruno Basso and published in Agriculture and Environmental Letters, is the first of its kind to provide critical insight to the importance of soil in managing risks associated with climate change.

"The long-term sustainability of agricultural systems strongly depends on how we use soil," Basso said. "This research proves that with the application of innovation through better soil management, we're one step closer to preserving our food supply and mitigating the effect that climate change and global warming has on our lives."

By learning how to scientifically harness, protect and improve soil's health, Basso's findings prove that crop yields can continue at current production levels or even improve -- especially if coupled with adaptive farming practices.

"Up until now, research hasn't accounted for what soil gives back to the cycle of climate change, and it is arguably the most critical resource to adapt to mitigate its effects," Basso said. "Ultimately, soil is the 'home' of the plants. If we aren't caring for the soil, plants and crops are unsheltered and left to deal with climate change on their own."

Basso's research was part of the Agricultural Model Intercomparing and Improvement Project, or AgMIP, a global initiative linking climate, crop and economic modeling communities to assess the fate of food production under climate change.

Basso spearheaded AgMIP's soil initiative and proposed that moving forward, soil be positioned as the center of the food production cycle.

"We went into the project knowing that with climate getting hotter, crop yields are forecasted to be lower. If the yield goes down, it also means that the amount of carbon that is returned to soil also goes down, so the question we had was: 'if this cycle continues, where do we end up, and what role will soil have? And, will we be worse off if we don't look after soil?' So we ran crop and soil models to simulate the impact of weather on a crop yield and soil organic carbon to evaluate the feedbacks from soil to climate change," Basso said.

Basso executed a series of models in Tanzania, Brazil, Argentina, the Netherlands, France, the United States and Australia to test soil's reactions to changes in temperature and carbon dioxide levels by analyzing soil organic carbon and nitrogen levels.

What the researchers found was that carbon dioxide compensated for the climate-caused yield losses because it acted as a natural fertilizer to help the crops grow. But when soil organic carbon losses were included in the analysis, the increased carbon dioxide in the atmosphere was not sufficient to prevent yield losses.

"So, through agronomic management, which is 'doing the right thing at the right time for your crops,' soil quality and health can be improved." Basso said.

Basso explained how farmers can practice better agronomic management to protect soil against the effects of climate change. This should include the use of cover crops, conservation tillage, adding organic carbon to soil or by increasing yields through advanced genetics and agronomy.

The forward-thinking approach to crop management -- and our global food supply -- is largely grounded at the root of plants' life cycle in the soil they're planted.

Read more at Science Daily

BUFFALO charges towards the earliest galaxies

The galaxy cluster Abell 370 was the first target of the BUFFALO survey, which aims to search for some of the first galaxies in the Universe.
The NASA/ESA Hubble Space Telescope has started a new mission to shed light on the evolution of the earliest galaxies in the Universe. The BUFFALO survey will observe six massive galaxy clusters and their surroundings. The first observations show the galaxy cluster Abell 370 and a host of magnified, gravitationally lensed galaxies around it.

Learning about the formation and evolution of the very first galaxies in the Universe is crucial for our understanding of the cosmos. While the NASA/ESA Hubble Space Telescope has already detected some of the most distant galaxies known, their numbers are small, making it hard for astronomers to determine if they represent the Universe at large.

Massive galaxy clusters like Abell 370, which is visible in this new image, can help astronomers find more of these distant objects. The immense masses of galaxy clusters make them act as cosmic magnifying glasses. A cluster's mass bends and magnifies light from more distant objects behind it, uncovering objects otherwise too faint for even Hubble's sensitive vision. Using this cosmological trick -- known as strong gravitational lensing -- Hubble is able to explore some of the earliest and most distant galaxies in the Universe.

Numerous galaxies are lensed by the mass of Abell 370. The most stunning demonstration of gravitational lensing can be seen just below the centre of the cluster. Nicknamed "the Dragon," this extended feature is made up of a multitude of duplicated images of a spiral galaxy which lies beyond the cluster.

This image of Abell 370 and its surroundings was made as part of the new Beyond Ultra-deep Frontier Fields And Legacy Observations (BUFFALO) survey. This project, led by European astronomers from the Niels Bohr Institute (Denmark) and Durham University (UK), was designed to succeed the successful Frontier Fields project. 101 Hubble orbits -- corresponding to 160 hours of precious observation time -- have been dedicated to exploring the six Frontier Field galaxy clusters. These additional observations focus on the regions surrounding the galaxy clusters, allowing for a larger field of view.

BUFFALO's main mission, however, is to investigate how and when the most massive and luminous galaxies in the Universe formed and how early galaxy formation is linked to dark matter assembly. This will allow astronomers to determine how rapidly galaxies formed in the first 800 million years after the Big Bang -- paving the way for observations with the upcoming NASA/ESA/CSA James Webb Space Telescope.

Driven by the Frontier Fields observations, BUFFALO will be able to detect the most distant galaxies approximately ten times more efficiently than its progenitor. The BUFFALO survey will also take advantage of other space telescopes which have already observed the regions around the clusters. These datasets will be included in the search for the first galaxies.

Read more at Science Daily

Earth's oldest animals formed complex ecological communities

These are Ediacara biota fossils found during Darroch's latest research in Namibia.
A new analysis is shedding light on Earth's first macroscopic animals: the 570-million-year-old, enigmatic Ediacara biota.

Ediacaran fossils have a slightly bizarre appearance not shared by any modern animal groups. For decades, researchers believed these enigmatic fossils were ecologically simple. However, borrowing a method from modern ecology -- fitting species to relative abundance distributions -- Vanderbilt University paleontologist Simon A.F. Darroch and his team learned that these organisms were more like modern animals than once thought.

The analyses showed that a majority of fossil assemblages bear the hallmarks of being ecologically complex, and Ediacara biota were forming complex communities tens of millions of years before the Cambrian explosion. The creatures lived partially submerged in what was once the ocean floor, some of them suspension feeding, others filter feeding, still others passively absorbing nutrition. A few were even mobile.

Complex communities are ones that comprise species competing for numerous different resources or species that create niches for others (as in many modern-day ecosystems). The team found that the signature of complex communities extends all the way back to the oldest Ediacaran fossils. In other words, as soon as macroscopic life evolved, it began forming diverse ecological communities not unlike those in the present day.

"The main impact of our work was testing between the simple and complex models for Ediacaran ecosystems," said Darroch, an assistant professor in Vanderbilt's Earth and Environmental Sciences Department.

"Supporting a simple model would suggest that these mysterious organisms were universally primitive, sharing the same basic ecology and all competing for the same resources," he said. "Support for the complex model would instead suggest that they likely competed for a variety of different resources, just like modern animals. Our analyses support the complex model, illustrating that -- even though they may look bizarre -- these mysterious fossils may have far more in common with modern animals than we thought."

Their paper, "High ecological complexity in benthic Ediacaran communities," is available online today in Nature Ecology & Evolution.

The team first compiled all Ediacaran fossil data from the published literature then added a dataset collected during fieldwork in southern Namibia. These Namibian fossils are the some of the youngest from anywhere in the world and record communities that were living immediately prior to the onset of the Cambrian explosion.

The fossils formed one of the few simple communities in the analysis, suggesting that these organisms were ecologically stressed. That lends support to the idea that the Ediacara biota were gradually going extinct in the run-up to the Cambrian explosion. Although it's an exciting idea, Darroch said, it's only one data point and will need much more research to prove.

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Never-before-seen features found around a neutron star

This illustration shows a neutron star (RX J0806.4-4123) with a disk of warm dust that produces an infrared signature as detected by NASA's Hubble Space Telescope. The disk wasn't directly photographed, but one way to explain the data is by hypothesizing a disk structure that could be 18 billion miles across. The disk would be made up of material falling back onto the neutron star after the supernova explosion that created the stellar remnant.
An unusual infrared light emission from a nearby neutron star detected by NASA's Hubble Space Telescope could indicate new features never before seen. One possibility is that there is a dusty disk surrounding the neutron star; another is that there is an energetic wind coming off the object and slamming into gas in interstellar space the neutron star is plowing through.

Although neutron stars are generally studied in radio and high-energy emissions, such as X-rays, this study demonstrates that new and interesting information about neutron stars can also be gained by studying them in infrared light, say researchers.

The observation, by a team of researchers at Pennsylvania State University, University Park, Pennsylvania; Sabanci University, Istanbul, Turkey; and the University of Arizona, Tucson, Arizona, could help astronomers better understand the evolution of neutron stars -- the incredibly dense remnants after a massive star explodes as a supernova. Neutron stars are also called pulsars because their very fast rotation (typically fractions of a second, in this case 11 seconds) causes time-variable emission from light-emitting regions.

A paper describing the research and two possible explanations for the unusual finding appears Sept. 17, 2018, in the Astrophysical Journal.

"This particular neutron star belongs to a group of seven nearby X-ray pulsars -- nicknamed 'the Magnificent Seven' -- that are hotter than they ought to be considering their ages and available energy reservoir provided by the loss of rotation energy," said Bettina Posselt, associate research professor of astronomy and astrophysics at Pennsylvania State and the lead author of the paper. "We observed an extended area of infrared emissions around this neutron star -- named RX J0806.4-4123 -- the total size of which translates into about 200 astronomical units (approximately 18 billion miles) at the assumed distance of the pulsar."

This is the first neutron star in which an extended signal has been seen only in infrared light. The researchers suggest two possibilities that could explain the extended infrared signal seen by Hubble. The first is that there is a disk of material -- possibly mostly dust -- surrounding the pulsar.

"One theory is that there could be what is known as a 'fallback disk' of material that coalesced around the neutron star after the supernova," said Posselt. "Such a disk would be composed of matter from the progenitor massive star. Its subsequent interaction with the neutron star could have heated the pulsar and slowed its rotation. If confirmed as a supernova fallback disk, this result could change our general understanding of neutron star evolution."

The second possible explanation for the extended infrared emission from this neutron star is a "pulsar wind nebula."

"A pulsar wind nebula would require that the neutron star exhibits a pulsar wind," said Posselt. "A pulsar wind can be produced when particles are accelerated in the electrical field that is produced by the fast rotation of a neutron star with a strong magnetic field. As the neutron star travels through the interstellar medium at greater than the speed of sound, a shock can form where the interstellar medium and the pulsar wind interact. The shocked particles would then emit synchrotron radiation, causing the extended infrared signal that we see. Typically, pulsar wind nebulae are seen in X-rays and an infrared-only pulsar wind nebula would be very unusual and exciting."

Read more at Science Daily

Sep 16, 2018

The art of storytelling: Researchers explore why we relate to characters

A figure showing the brain scans of study participants who were asked to tell stories using different forms.
For thousands of years, humans have relied on storytelling to engage, to share emotions and to relate personal experiences. Now, psychologists at McMaster University are exploring the mechanisms deep within the brain to better understand just what happens when we communicate.

New research published in the Journal of Cognitive Neuroscience, suggests that no matter how a narrative is expressed -- through words, gestures or drawings -- our brains relate best to the characters, focusing on the thoughts and feelings of the protagonist of each story.

"We tell stories in conversation each and every day," explains Steven Brown, lead author of the study, who runs the NeuroArts Lab at McMaster and is an associate professor in the Department of Psychology, Neuroscience ang Behaviour. "Very much like literary stories, we engage with the characters and are wired to make stories people-oriented."

An important question researchers set out to answer was how, exactly, narrative ideas are communicated using three different forms of expression, and to identify a so-called narrative hub within the brain.

For the study, researchers scanned the brains of participants using fMRI and presented them with short headlines. For example, "Surgeon finds scissors inside of patient" or "Fisherman rescues boy from freezing lake."

They were then asked to convey the stories using speech, gestures or drawing, as one would do in a game of Pictionary. The illustrations were created using an MRI-compatible drawing tablet which allowed the participants to see their drawings.

Researchers found that no matter what form of story telling the participants used, the brain networks that were activated were the "theory-of-the-mind" network, which is affected by the character's intentions, motivations, beliefs, emotions and actions.

"Aristotle proposed 2,300 years ago that plot is the most important aspect of narrative, and that character is secondary," says Brown. "Our brain results show that people approach narrative in a strongly character-centered and psychological manner, focused on the mental states of the protagonist of the story."

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Geologists reveal ancient connection between England and France

This graphic shows how the ancient land masses of Laurentia, Avalonia and Armorica would have collided to create the countries of England, Scotland and Wales.
The British mainland was formed from the collision of not two, but three ancient continental land masses, according to new research.

Scientists have for centuries believed that England, Wales and Scotland were created by the merger of Avalonia and Laurentia more than 400 million years ago.

However, geologists based at the University of Plymouth now believe that a third land mass -- Armorica -- was also involved in the process.

The findings are published in Nature Communications and follow an extensive study of mineral properties at exposed rock features across Devon and Cornwall.

They reveal a clear boundary running across the two counties, with areas north of it sharing their geological roots with the rest of England and Wales but everything south being geologically linked to France and mainland Europe.

Among other things, scientists believe the research explains the abundance of tin and tungsten in the far South West of England -- metals also found in Brittany and other areas of mainland Europe, but not so evident in the rest of the UK.

The research's lead author, Lecturer in Igneous Petrology Dr Arjan Dijkstra, said: "This is a completely new way of thinking about how Britain was formed. It has always been presumed that the border of Avalonia and Armorica was beneath what would seem to be the natural boundary of the English Channel. But our findings suggest that although there is no physical line on the surface, there is a clear geological boundary which separates Cornwall and south Devon from the rest of the UK."

For the research, Dr Dijkstra and Masters student Callum Hatch (now working at the Natural History Museum) visited 22 sites in Devon and Cornwall that were left exposed following geological events, such as underground volcanic eruptions. These took place around 300 million years ago and brought magma from depths of 100 km to the Earth's surface.

They took rock samples from each site, subjecting them to detailed chemical analysis in the lab using X-ray fluorescence (XRF) spectrometry.

The samples were also then dissolved in acid in order to conduct a more intensive isotopic analysis, with scientists examining the levels of two elements -- strontium and neodymium -- to understand the full history of the rocks.

These findings were then compared with previous studies elsewhere in the UK and mainland Europe, with the results showing the clear boundary running from the Exe estuary in the East to Camelford in the west.

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