Skin-ditching gecko inexplicably leaves body armor behind when threatened

Fish-scale geckos shed their skin when threatened. But CT scans reveal bony deposits -- essentially body armor -- in their scales, raising the question of why the geckos seem to have conflicting defense strategies.

When trouble looms, the fish-scale geckos of Madagascar resort to what might seem like an extreme form of self-defense -- tearing out of their own skin.

Their unusually large, overlapping scales flake off so easily that one biologist in the late 1800s tried collecting the geckos with cotton, but even with careful handling, few fish-scale gecko specimens have been preserved with all scales intact.

Now, new research published in the African Journal of Herpetology shows the geckos' fragile skin contains a hidden strength. Inside the scales are bony deposits known as osteoderms, the same material that makes up the tough scales and plates of crocodilians and armadillos. But the presence of osteoderms in fish-scale geckos raises a herpetological mystery: If they have armor, why do they discard it?

"The big question is why there are these conflicting defense strategies," said Daniel Paluh, the study's lead author and a doctoral student at the Florida Museum of Natural History. "This gecko can actually drop its skin as a defense mechanism, but it also has these mineralizations -- usually thought of as body armor -- that it's just leaving behind."

As part of his research as a master's student at Villanova University, Paluh studied hundreds of geckos using computed tomography (CT) technology, which uses thousands of X-rays to create high-resolution, multilayered 3-D images of specimens. The CT scan of Geckolepis maculata, a species in the fish-scale genus, revealed dense bony material inside the skin, a feature Paluh had not noticed in most other geckos.

"I thought, 'Wow, this is really strange,' " he said. "We started diving deeper to verify that what we were seeing in the CT scan were actually these mineralized elements."

Osteoderms are found in some lizards, but they are rare in geckos, a group that includes more than 1,600 species. Prior to Paluh's study, only the genus Tarentola, or wall geckos, and Gekko gecko, the tokay gecko, were known to have this protective outer armor.

Most geckos have thin skin covered in tiny, granular scales and tend to rely on camouflage and the cover of night to hide from predators, Paluh said.

Some groups, such as Geckolepis, have also evolved weak skin as a form of defense, said Aaron Bauer, the Gerald M. Lemole Endowed Chair in Integrative Biology at Villanova University and co-author of the study. When a predator strikes, these geckos can rip out of their skin to escape, "like the tear-away football jerseys of the 1970s," he said.

The apparent paradox of "sheddable armor" contributed to the widespread questioning of a paper by biologist W.J. Schmidt, who in 1911 published his observations of osteoderms in the scales of Geckolepis polyepis. His findings were met with skepticism for decades until Paluh's CT scan proved Schmidt was right.

"Schmidt had to illustrate what he saw, which could have contributed to his work being questioned," Paluh said. "It was unclear whether he was replicating the histology accurately. The advantage we have today is that we can combine newer, innovative tools with traditional methods than have been used for hundreds of years. It provides a new perspective to some of the classical anatomical observations."

To verify the presence of osteoderms in G. maculata, Paluh used techniques similar to Schmidt's. He cleared and stained excised patches of skin containing multiple scales to determine if the tissue was mineralized. Removing the skin revealed tiny, interlocking osteoderms similar to those Schmidt described and illustrated more than a century earlier.

"Schmidt was a great anatomist, and I'm sure that he was confident in what he saw," Bauer said. "Indeed, anatomists of his time, working with much less technically advanced equipment than we have today, were pretty good about getting animal anatomy right."

Paluh said osteoderms might not necessarily serve as a defensive shield. They could contribute calcium for egg development in female geckos or help regulate body temperature.

The researchers hypothesize that osteoderms likely evolved independently in Geckolepis, Tarentola and Gekko gecko. The geckos are not close relatives, and CT scans showed osteoderm structure and density vary among the three. G. gecko and Tarentola mauritanica have plate-like and granular osteoderms, while in G. maculata, the deposits resemble the small irregular pieces of a mosaic.

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Origin of human genus may have occurred by chance

Archaeological excavation

An often cited claim that humans, who are smarter and more technologically advanced than their ancestors, originated in response to climate change is challenged in a new report by a Center for the Advanced Study of Human Paleobiology researcher at George Washington University.

Many scientists have argued that an influx, described as a "pulse," of new animal species appear in the African fossil record between 2.8 and 2.5 million years ago, including our own genus Homo. Experts believe it takes a broad-scale event like global climate change to spark the origination of so many diverse new species. However, W. Andrew Barr, a visiting assistant professor of anthropology, published a report that says it's possible the pulse of new species could have occurred by chance and might not be directly related to climate change.

It is generally accepted that when major environmental changes occur, some species will go extinct and others will originate, which can create a cluster or pulse of new species in the fossil record. However, there is not a set definition of what is considered a pulse, so experts have disagreed about which clusters constitute meaningful events and which can be explained as random fluctuations.

Dr. Barr used computer simulation to model what the fossil record might look like over time in the absence of any climate change and found clusters of species originations that were of similar magnitude to the clusters observed in the fossil record. This means random patterns are likely under-credited for their role in speciation fluctuation, he said.

Dr. Barr's findings mean scientists may need to rethink widely-accepted ideas about why human ancestors became smarter and more sophisticated.

"The idea that our genus originated more than 2.5 million years ago as part of a turnover pulse in direct response to climate change has a deep history in paleonthropology," Dr. Barr said. "My study shows that the magnitude of that pulse could be caused by random fluctuations in speciation rates. One implication is that we may need to broaden our search for why our genus arose at that time and place."

He compared the pattern to flipping a coin. If you flip a coin 100 times, you would expect to record 50 heads and 50 tails. However, if you are only looking at 10 coin flips, you could see a greater imbalance, instead recording seven heads and only three tails. This would even out over time, but in the short-run, you could see clusters of these independent coin flips, he said.

Similarly, fluctuations in turnover in Dr. Barr's model are pronounced, but are caused purely by random processes.

"The idea the the origin of Homo is part of a climate-caused turnover pulse doesn't really bear out when you carefully look at the evidence and compare it against other possible explanations," Dr. Barr said.

This research challenges scientists to be careful about the stories they tell about the history of human adaption, Dr. Barr said. Traits that make humans different from our ancestors, like larger brains and greater technological sophistication, could have arisen for a variety of reasons, he said.

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Primordial black holes may have helped to forge heavy elements

Artist’s depiction of a neutron star.

Astronomers like to say we are the byproducts of stars, stellar furnaces that long ago fused hydrogen and helium into the elements needed for life through the process of stellar nucleosynthesis.

As the late Carl Sagan once put it: "The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star stuff."

But what about the heavier elements in the periodic chart, elements such as gold, platinum and uranium?

Astronomers believe most of these "r-process elements" -- elements much heavier than iron -- were created, either in the aftermath of the collapse of massive stars and the associated supernova explosions, or in the merging of binary neutron star systems.

"A different kind of furnace was needed to forge gold, platinum, uranium and most other elements heavier than iron," explained George Fuller, a theoretical astrophysicist and professor of physics who directs UC San Diego's Center for Astrophysics and Space Sciences. "These elements most likely formed in an environment rich with neutrons."

In a paper published August 7 in the journal Physical Review Letters, he and two other theoretical astrophysicists at UCLA -- Alex Kusenko and Volodymyr Takhistov -- offer another means by which stars could have produced these heavy elements: tiny black holes that came into contact with and are captured by neutron stars, and then destroy them.

Neutron stars are the smallest and densest stars known to exist, so dense that a spoonful of their surface has an equivalent mass of three billion tons.

Tiny black holes are more speculative, but many astronomers believe they could be a byproduct of the Big Bang and that they could now make up some fraction of the "dark matter" -- the unseen, nearly non-interacting stuff that observations reveal exists in the universe.

If these tiny black holes follow the distribution of dark matter in space and co-exist with neutron stars, Fuller and his colleagues contend in their paper that some interesting physics would occur.

They calculate that, in rare instances, a neutron star will capture such a black hole and then devoured from the inside out by it. This violent process can lead to the ejection of some of the dense neutron star matter into space.

"Small black holes produced in the Big Bang can invade a neutron star and eat it from the inside," Fuller explained. "In the last milliseconds of the neutron star's demise, the amount of ejected neutron-rich material is sufficient to explain the observed abundances of heavy elements."

"As the neutron stars are devoured," he added, "they spin up and eject cold neutron matter, which decompresses, heats up and make these elements."

This process of creating the periodic table's heaviest elements would also provide explanations for a number of other unresolved puzzles in the universe and within our own Milky Way galaxy.

"Since these events happen rarely, one can understand why only one in ten dwarf galaxies is enriched with heavy elements," said Fuller. "The systematic destruction of neutron stars by primordial black holes is consistent with the paucity of neutron stars in the galactic center and in dwarf galaxies, where the density of black holes should be very high."

In addition, the scientists calculated that ejection of nuclear matter from the tiny black holes devouring neutron stars would produce three other unexplained phenomenon observed by astronomers.

"They are a distinctive display of infrared light (sometimes termed a "kilonova"), a radio emission that may explain the mysterious Fast Radio Bursts from unknown sources deep in the cosmos, and the positrons detected in the galactic center by X-ray observations," said Fuller. "Each of these represent long-standing mysteries. It is indeed surprising that the solutions of these seemingly unrelated phenomena may be connected with the violent end of neutron stars at the hands of tiny black holes."

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Source of Human Heartbeat Revealed in 3-D

Scan of a heart.

A pioneering new study is set to help surgeons repair hearts without damaging precious tissue.

A team of scientists from Liverpool John Moores University (LJMU), The University of Manchester, Aarhus University and Newcastle University, have developed a way of producing 3D data to show the cardiac conduction system -- the special cells that enable our hearts to beat -- in unprecedented detail. The findings were published in Scientific Reports.

The new data in this study gives them a much more accurate framework than previously available for computer models of the heartbeat and should improve our ability to make sense of troublesome heart rhythms like atrial fibrillation that affects 1.4 million people in the UK. The data reveals exactly where the cardiac conduction system is in a normal heart. For example, it shows just how close it runs to the aortic valve.

Professor Jonathan Jarvis who is based at the LJMU School of Sport and Exercise Sciences explained: "The 3D data makes it much easier to understand the complex relationships between the cardiac conduction system and the rest of the heart. We also use the data to make 3D printed models that are really useful in our discussions with heart doctors, other researchers and patients with heart problems.

"New strategies to repair or replace the aortic valve must therefore make sure that they do not damage or compress this precious tissue. In future work we will be able to see where the cardiac conduction system runs in hearts that have not formed properly. This will help the surgeons who repair such hearts to design operations that have the least risk of damaging the cardiac conduction system."

Co-author Dr Halina Dobrzynski, who is based in The University of Manchester's Cardiovascular Division, has been working on the anatomy of the cardiac conduction system for 20 years. She says: "This is just the beginning. The British Heart Foundation is supporting my group to visualise this system in 3D from aged and failing hearts. With my research assistant Andrew Atkinson and working with Professor Jonathan Jarvis, Robert Stephenson and others, we will produce families of data from aged and failing hearts in 3D."

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Unknown virus discovered in 'throwaway' DNA

A chance discovery has opened up a new method of finding unknown viruses.

A chance discovery has opened up a new method of finding unknown viruses.

In research published in the journal Virus Evolution, scientists from Oxford University's Department of Zoology have revealed that Next-Generation Sequencing and its associated online DNA databases could be used in the field of viral discovery. They have developed algorithms that detect DNA from viruses that happen to be in fish blood or tissue samples, and could be used to identify viruses in a range of different species.

Next-Generation Sequencing has revolutionised genomics research and is currently used to study and understand genetic material. It allows scientists to gather vast amounts of data, from a single piece of DNA, which is then collated into huge, online, genome databases that are publicly accessible.

Dr Aris Katzourakis and Dr Amr Aswad, Research Associates at Oxford's Department of Zoology, initially discovered the new use for the database, by chance. While looking for an ancient herpes virus in primates, they found evidence of two new undocumented viruses.

Spurred by their accidental discovery, they set out to see if they could intentionally achieve the same result. In a separate project to find new fish-infecting herpes viruses, they used the technique to examine more than 50 fish genomes for recognisable viral DNA. Sure enough, in addition to the herpes viruses they were expecting to find, the researchers identified a distant lineage of unusual viruses -- that may even be a new viral family. The traits were found scattered in fragments of 15 different species of fish, including the Atlantic salmon and rainbow trout.

To confirm that the viral evidence was not simply a fluke, or a data processing error, they tested additional samples from a local supermarket and sushi restaurant. The same viral fragments were found in the bought samples.

Study author Dr Aris Katzourakis, from Oxford University's Department of Zoology, said: 'In the salmon genome we found what seems to be a complete and independent viral genome, as well as dozens of fragments of viral DNA that had integrated into the fish DNA. We know from recent studies that viruses are able to integrate into the genome of their host, sometimes remaining there for millions of years. In this case, it looks like the virus may have acquired the ability to integrate by stealing a gene from the salmon itself, which explains how it has become so widespread in the salmon genome.'

The key to the success of this research is in its inter-disciplinary approach, combining techniques from two fields: evolutionary biology and genomics. Together, these are at the core of the new field of paleovirology -- the study of ancient viruses that have integrated their DNA into that of their hosts, sometimes millions of years ago. Each technique used has been developed to analyse huge quantities of DNA sequence data.

Co-author and Research Associate at Oxford's Department of Zoology and St. Hilda's College, Dr Amr Aswad, said: 'Discovering new viruses has historically been biased towards people and animals that exhibit symptoms of disease. But, our research shows how useful next generation DNA sequencing can be in viral identification. To many, viral DNA in say, chimp or falcon data is a nuisance, and a rogue contaminant that needs to be filtered from results. But we consider these an opportunity waiting to be exploited, as they could include novel viruses that are worth studying -- as we have found in our research. We could be throwing away very valuable data.'

Finding new viruses has historically not been an easy process. Cells do not grow on their own, so must be cultured in a laboratory before they can be analysed, which involves months of work. But the Oxford research represents a massive opportunity for the future.

Beyond this study, the approach could be used to identify viruses in a range of different species, particularly those known to harbour transmissible disease. Bats and rodents, for example, are notorious carriers of infectious disease that they are seemingly immune to. Insects such as mosquitoes are also carriers of viral diseases that harm humans, such as Zika. If applied effectively the method could uncover other viruses before an outbreak even happens.

Dr Katzourakis added: 'One of the real strengths of this technique, as compared to more traditional virology approaches, is the speed of discovery, and the lack of reliance on identifying a diseased individual. The viral data collected, that may otherwise be discarded as a nuisance, is a unique resource for looking for both pathogenic and benign viruses that would otherwise have remained undiscovered.'

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On the early human's menu: Mammoth and plenty of raw vegetables

Occipital bone of an anatomically modern human from the fossil site Buran-Kaya III.

Senckenberg scientists have studied the diet of anatomically modern humans. With their recent study, published in the journal Scientific Reports, they were able to refute the theory that the diet of early representatives of Homo sapiens was more flexible than that of Neanderthals. Just like the Neanderthals, our ancestors had mainly mammoth and plants on their plates -- the researchers were unable to document fish as part of their diet. Therefore, the international team assumes that the displacement of the Neanderthals was the result of direct competition.

The first representatives of Homo sapiens colonized Europe around 43,000 years ago, replacing the Neanderthals there approximately 3,000 years later. "Many studies examine the question of what led to this displacement -- one hypothesis postulates that the diet of the anatomically modern humans was more diverse and flexible and often included fish," explains Prof. Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) at the University of Tübingen

Together with his colleague, Dr. Dorothée Drucker, the biogeologist from Tübingen now set out to get to the bottom of this hypothesis. In conjunction with an international team, he studied the dietary habits of early modern man on the basis of the oldest know fossils from the Buran Kaya caves on the Crimean Peninsula in the Ukraine. "In the course of this study, we examined the finds of early humans in the context of the local fauna," explains Drucker, and she continues, "Until now, all analyses of the diet of early modern humans were based on isolated discoveries; therefore, they are very difficult to interpret."

In order to reconstruct our ancestor's menu -- despite the lack of a fossil dietary record -- the team around the scientists from Tübingen measured the percentage of stable carbon and nitrogen isotopes in the bones of the early humans and the locally present potential prey animals such as Saiga, horses, and deer. In addition, they also analyzed the nitrogen-15 content of individual amino acids, making it possible to not only determine the origin, but also the proportion of the nitrogen. "Our results reveal a very high proportion of the nitrogen isotope 15N in early modern humans," adds Bocherens, and he continues, "However, contrary to our previous assumptions, these do not originate from the consumption of fish products, but primarily from mammoths."

And yet another result came as a surprise for the scientists: The proportion of plants in the diet of the anatomically modern humans was significantly higher than in comparable Neanderthal finds -- mammoths, on the other hand, appear to have been one of the primary sources of meat in both species.

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Egyptologists Embrace Cutting-Edge Technology to Solve Ancient Mysteries

The Pyramids of Menkaure, Khafre and Khufu, Giza Necropolis (UNESCO World Heritage List, 1979), Egypt. Egyptian civilization, Old Kingdom, Dynasty IV.

From the Giza pyramids to the pharaonic tombs of Luxor, Egypt's ancient monuments are holding onto mysteries which researchers now aim to unravel with cutting edge technology.

For more than 200 years since Napoleon Bonaparte landed in Egypt with a retinue of scholars who laid the groundwork for modern Egyptology, experts have used science to unlock the secrets of the country's ancient treasures.

In the 21st century, the scientists have been using electronic devices and chemical testing to date artifacts.

Chemical testing still requires small samples, but advanced techniques coming into use are meant to be noninvasive so as not to damage the ancient relics.

ScanPyramids is among the most ambitious of the projects to demystify the Khufu Pyramid near Cairo, the only surviving monument from the ancient Seven Wonders of the World.

It has employed infrared thermography and muography — a technique that records images using muon particles — in its quest.

The project had announced last October that the massive pyramid may contain undiscovered recesses.

"All the devices we put in place are designed to find where the cavity is located. We know there is one, but we're trying to find out where," said Mehdi Tayoubi, president of the HIP Institute heading the ScanPyramids project.

The muon devices include chemical emulsion instruments from Japan's University of Nagoya, electronic sensors from the KEK Japanese Research Laboratory, and muon telescopes from the French Atomic Energy Commission.

The results are then compared with infrared and 3D images.

Some archaeologists have pinned hopes on the sophisticated technology to locate the burial place of the legendary queen Nefertiti.   

The wife of King Akhenaten, who initiated a monotheistic cult in ancient Egypt, Nefertiti remains an enigma, best known for a bust depicting her that is now on exhibition in Berlin's Neues Museum.

A British Egyptologist, Nicholas Reeves, believed her remains were hidden in a secret chamber in the tomb of Tutankhamun, in the southern Valley of the Kings.

In 2015, archaeologists scanned the tomb with radar hoping for clues.

Both Reeves's theory and the inconclusive results have been dismissed by other Egyptologists.

One of them, former antiquities minister Zahi Hawass, said that an adept of the sun god Aton would never have been allowed to be buried in the Valley of the Kings.

Mapping out ancient dynasties

The excitement over the possible discovery has died down since the inconclusive results, but a team from Politecnico University in Turin, Italy, intends to give it another shot.

This time they will employ tomography — a method used in medical scans — and magnetometry, which measures magnetic fields.

Neither the Politecnico team nor the antiquities ministry has been inclined to discuss the fresh attempt, possibly put off by the anticlimactic media frenzy over the previous bid.

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Primordial asteroids discovered

Astronomers have identified the oldest asteroid families and, by process of elimination, the oldest intact asteroids in the main belt. A team including SwRI scientists developed a technique to identify ancient asteroid families that have drifted apart. Asteroid surfaces heat up during the day (as illustrated by this image) and cool down at night, giving off radiation that can act as a sort of mini-thruster. This force can cause asteroids to drift widely over time, making it difficult to identify families of fragments leftover after asteroid collisions eons ago.

Southwest Research Institute (SwRI) was part of an international team that recently discovered a relatively unpopulated region of the main asteroid belt, where the few asteroids present are likely pristine relics from early in solar system history. The team used a new search technique that also identified the oldest known asteroid family, which extends throughout the inner region of the main asteroid belt.

The main belt contains vast numbers of irregularly shaped asteroids, also known as planetesimals, orbiting the Sun between Mars and Jupiter. As improved telescope technology finds smaller and more distant asteroids, astronomers have identified clusters of similar-looking bodies clumped in analogous orbits. These familial objects are likely fragments of catastrophic collisions between larger asteroids eons ago. Finding and studying asteroid families allows scientists to better understand the history of main belt asteroids.

"By identifying all the families in the main belt, we can figure out which asteroids have been formed by collisions and which might be some of the original members of the asteroid belt," said SwRI Astronomer Dr. Kevin Walsh, a coauthor of the online Science paper detailing the findings. "We identified all known families and their members and discovered a gigantic void in the main belt, populated by only a handful of asteroids. These relics must be part of the original asteroid belt. That is the real prize, to know what the main belt looked like just after it formed."

Identifying the very oldest asteroid families, those billions of years old, is challenging, because over time, a family spreads out. As asteroids rotate in orbit around the Sun, their surfaces heat up during the day and cool down at night. This creates radiation that can act as a sort of mini-thruster, causing asteroids to drift widely over time. After billions of years, family members would be almost impossible to identify, until now. The team used a novel technique, searching asteroid data from the inner region of the belt for old, dispersed families. They looked for the "edges" of families, those fragments that have drifted the furthest.

"Each family member drifts away from the center of the family in a way that depends on its size, with small guys drifting faster and further than the larger guys," said team leader Marco Delbo, an astronomer from the Observatory of Cote d'Azur in Nice, France. "If you look for correlations of size and distance, you can see the shapes of old families."

"The family we identified has no name, because it is not clear which asteroid is the parent," Walsh said. "This family is so old that it appears to have formed over 4 billion years ago, before the gas giants in the outer solar system moved into their current orbits. The giant planet migration shook up the asteroid belt, removing many bodies, possibly including the parent of this family."

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We Could Be on the Threshold of a New Era of Color Science

Sunset over the colorful tulip fields in Karatay, Konya, Turkey on April 13, 2016.

An international team of 27 scientists has just declared that we are on the threshold of a new era of color science that could have far-reaching impacts on everything from the security industry to our understanding of animal and human behavior.

The declaration, published in the journal Science, follows multiple advances in the study of animal and plant coloration.

“New technology is opening new windows into exploration of color perception, production, and function,” senior author Tim Caro of the University of California, Davis, said.

Co-author Justin Marshall of the University of Queensland recently determined that mantis shrimp have four times as many color receptors as humans do. He explained that we have three — red, green, and blue — while the shrimp have twelve.

Lead author Innes Cuthill of the University of Bristol said mantis shrimp use those extra color channels to analyze light coming from objects in ways much different than humans and most other animals.

“They analyze light like a machine called a spectrometer, which a physicist would use to measure how much light there is in a set of wavebands,” he said. “We, and most other animals, instead transform the relative amounts of light in different wavebands into a single continuous percept: the sensation we call color.”

Peacock mantis shrimp (Odontodactylus scyllarus) photographed in the Andaman Sea, Thailand

Animals see the world differently than we do. For example, no human has yet set eyes on “bird white.” What we think of as “white” could also be something completely different to a bird.

“Objects that all look white to us may look different to a bird depending on how much ultraviolet light there is,” Cuthill said. “If there’s as much UV as blue, green, and red, that would be ‘bird white.’ If there was no UV, then that would be a saturated primary color to a bird, one we cannot imagine.”

Another recent finding in the field of color biology suggests patterns of color on a species can signal how well an individual can fight. Co-author Elizabeth Tibbetts of the University of Michigan first noted that black facial patterns vary on paper wasps. She then discovered that females with larger or a greater number of irregular black marks on their faces tended to win fights with their rivals.

Tibbetts explained that the facial signals help reduce the costs of conflict.

“Lots of animals have color patterns that convey information about fighting ability: birds, lizards, fish, mammals, insects,” she said. “It’s the animal version of advertising your fighting prowess with karate belt color. If you are a wimpy wasp, it doesn’t make sense to challenge the strongest wasp in the neighborhood to a fight.”

European paper wasp

Body coloration can be tied to many behaviors. Humans are not exempt from the color-behavior connection. In fact, many people who head to a sunny climate for spring or summer vacation may exemplify the phenomenon.

Caro explained that skin color in humans is the result of a trade-off between avoiding the harmful effects of ultraviolet radiation and the beneficial effects of vitamin-D production caused by sunlight hitting the skin.

“This trade-off can affect behavior,” he continued. “For example, people in northern European climates like to take advantage of the sun in spring and sunbathe to produce vitamin D after the long winter.”

Color in nature is usually tied to honest visual information. Human heritage, in this way, is reflected in an individual’s skin color.

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Exceptionally Well-Preserved Dinosaur Had Hefty Armor and Elaborate Camouflage

Right side of Borealopelta markmitchelli’s head

On March 21, 2011, mining machine operator Shawn Funk at the Suncor Millennium Mine in Alberta, Canada, spotted some unusual rock formations that he suspected could contain fossils. Since a bunch of plesiosaur and ichthyosaur remains had been previously excavated from the region, Donald Henderson, who is the curator of dinosaurs at Royal Tyrrell Museum in Drumheller, Canada, and a crew were sent to the mine to investigate.

Henderson and his colleagues at first were baffled by the fossils, which looked nothing like the marine reptile remains that had been unearthed in the Alberta area. The chunk of rock encasing the fossils was transported to the museum, where technician Mark Mitchell spent more than 7,000 hours slowly and gently removing material away from the specimen. When paleontologist Caleb Marshall Brown of the museum first saw the preserved beast in full, his jaw dropped.

There, in vivid 3D, was a nodosaur, which is a type of hefty armored dinosaur.

“This specimen is one of the best-preserved dinosaur specimens ever found,” Brown said. “What sets this nodosaur apart from other exceptionally preserved dinosaur specimens, is the unique combination of both abundant skin preservation and retention of the original three-dimensional form of the body.”

“This unique combination means that, with the exception of the color, the animal looks the same today as it did when it was alive,” he added. “It is almost as if the animal went to sleep and turned to stone — a fossil masterpiece.”

In honor of Mitchell, the dinosaur was named Borealopelta markmitchelli. The new species, now considered to be the world’s best-preserved armored dinosaur, is described in the journal Current Biology. Dated to 110 million years ago, this “dinosaur equivalent of a tank,” according to the authors, weighed in at more than 2,800 pounds and grew to at least 18 feet long.

The mine site during the Early Cretaceous was a sea, which is one reason why Henderson and his team first thought the fossils belonged to a marine reptile. The researchers, whose work was supported by the National Geographic Society, can piece together the extraordinary circumstances that led to the dinosaur’s preservation.

Henderson explained that, after the dino died, its armor still would have been anchored into the skin in a dense, collagenous mesh.

“This armor would have deterred scavengers from trying to pull off chunks while it floated on the water surface,” he said. “The thick hide also was able to contain the high gas pressure that would have built up inside the decaying carcass. A fully inflated, super buoyant carcass was able to float far offshore away from damaging waves crashing on a beach.”

An illustration of the 110-million-year-old Borealopelta markmitchelli discovered in Alberta, Canada

The dinosaur’s body wall did eventually rupture. The carcass then drifted down to the seabed in water that was at least 164 feet deep. Few fossils from burrowing species exist at that spot, suggesting low-oxygen conditions with little biological activity. There, the carcass remained undisturbed until Funk’s fateful day.

The animal’s thick hide, which aided preservation of the remains, still retains organic material, such as pigments. These biomolecules show that B. markmitchelli had reddish-brown skin that was darker at the top and lighter on the animal’s underside. This light-dark combination is common in animals alive today and is known as countershading.

Co-author Jakob Vinther of the University of Bristol explained that countershading helps animals to blend into their landscapes, camouflaging their 3D forms. The dinosaur lived in a dry and open environment where the ground and vegetation exhibited earthen tones of brown, yellow, and red. Its reddish-brown hues strengthened the camouflage effect.

It was thought that few predators dared to take on husky armored dinosaurs, but B. markmitchelli evolved more for defense than offense. Brown and Henderson suspect that Acrocanthosaurus, a gigantic meat-loving dinosaur that measured around 38 feet long and weighed about 6.8 tons, hunted the armored dinosaur.

“The best anti-predatory defense that Borealopelta had would have been avoiding detection in the first place, and then looking like an unappetizing meal — by being covered in bony armor,” Brown said.

Frontal view of Borealopelta markmitchelli

Henderson agreed, adding that the nodosaur probably hunkered down as a last resort, hoping that its armor would hold if the predator tried to take a bite.

The dinosaur is so well preserved that organic remains of its last meal appear to be present in its fossilized gut. Vinther said he and his colleagues “have some idea” concerning what this meal consisted of, but they wish to conduct a chemical analysis and other investigations before coming to a conclusion.

Read more at Seeker

Millions More People Could Face Protein Deficiency Due to Climate Change

Farmers harvest summer wheat on wheat field on June 12, 2017 in Lianyungang, Jiangsu Province of China.

Rising carbon dioxide levels from global warming will drastically reduce the amount of protein in staple crops like rice and wheat, leaving vulnerable populations at risk of growth stunting and early death, experts warned Wednesday.

Researchers say they still don't understand how or why carbon dioxide emissions sap protein and other nutrients from plants, but the mystery is one that could have devastating consequences across the globe.

An additional 150 million people globally may be at risk of protein deficiency by 2050 because of rising levels of carbon dioxide in the atmosphere said the report in the journal Environmental Research Letters.

The study, led by Harvard University researchers, is the first to quantify the impacts of global warming on the protein levels of crops.

It relies on data from open field experiments in which plants were exposed to high concentrations of CO2.

Global dietary information from the United Nations was used to calculate the impact on people who live dangerously close to the edge when it comes to getting enough protein. Without it, growth is stunted, diseases are more common and early mortality is far more likely.

Carbon dioxide is a byproduct of fossil-fuel burning that helps trap heat around the Earth. Without stark action, these emissions are expected to climb in the decades to come, resulting in rising seas, hotter temperatures, and more extreme weather events.

A leading hypothesis was that CO2 might increase the amount of starch in plants, thereby decreasing protein and other nutrients.

But lead author Samuel Myers, a senior research scientist in Harvard University's T.H. Chan School of Public Health, said that experiments did not back up the theory.

"The short answer is we really have no idea," he told AFP.

"We've looked into it pretty extensively."

Protein was not the only nutrient to take a major hit.

Other research has shown that rising CO2 will cut key minerals like iron and zinc in staple crops, leading to further nutritional deficiencies worldwide.

Africa, Asia hardest hit

Researchers calculated that by 2050, higher CO2 concentrations will sap the protein contents of barley by 14.6 percent, rice by 7.6 percent, wheat by 7.8 percent, and potatoes by 6.4 percent.

"If CO2 levels continue to rise as projected, the populations of 18 countries may lose more than 5 percent of their dietary protein by 2050 due to a decline in the nutritional value of rice, wheat, and other staple crops," said the report.

A full 76 percent of the people on Earth rely on plants for most of their daily protein, particularly in poor areas of the globe.

The hardest hit areas are expected to be Sub-Saharan Africa, where millions already don't get enough protein in their diets, and South Asia where rice and wheat are common staples.

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New simulations could help in hunt for massive mergers of neutron stars, black holes

This image, from a computerized simulation, shows the formation of an inner disk of matter and a wide, hot disk of matter 5.5 milliseconds after the merger of a neutron star and a black hole.

Now that scientists can detect the wiggly distortions in space-time created by the merger of massive black holes, they are setting their sights on the dynamics and aftermath of other cosmic duos that unify in catastrophic collisions.

Working with an international team, scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have developed new computer models to explore what happens when a black hole joins with a neutron star -- the superdense remnant of an exploded star.

Using supercomputers to rip open neutron stars

The simulations, carried out in part at Berkeley Lab's National Energy Research Scientific Computing Center (NERSC), are intended to help detectors home in on the gravitational-wave signals. Telescopes, too, can search for the brilliant bursts of gamma-rays and the glow of the radioactive matter that these exotic events can spew into surrounding space.

In separate papers published in a special edition of the scientific journal Classical and Quantum Gravity, Berkeley Lab and other researchers present the results of detailed simulations.

One of the studies models the first milliseconds (thousandths of a second) in the merger of a black hole and neutron star, and the other details separate simulations that model the formation of a disk of material formed within seconds of the merger, and of the evolution of matter that is ejected in the merger.

That ejected matter likely includes gold and platinum and a range of radioactive elements that are heavier than iron.

Any new information scientists can gather about how neutron stars rip apart in these mergers can help to unlock their secrets, as their inner structure and their likely role in seeding the universe with heavy elements are still shrouded in mystery.

"We are steadily adding more realistic physics to the simulations," said -- Foucart, who served as a lead author for one of the studies as a postdoctoral researcher in Berkeley Lab's Nuclear Science Division.

"But we still don't know what's happening inside neutron stars. The complicated physics that we need to model make the simulations very computationally intensive."

Finding signs of a black hole-neutron star merger

Foucart, who will soon be an assistant professor at the University of New Hampshire, added, "We are trying to move more toward actually making models of the gravitational-wave signals produced by these mergers," which create a rippling in space-time that researchers hope can be detected with improvements in the sensitivity of experiments including Advanced LIGO, the Laser Interferometer Gravitational-Wave Observatory.

In February 2016, LIGO scientists confirmed the first detection of a gravitational wave, believed to be generated by the merger of two black holes, each with masses about 30 times larger than the sun.

The signals of a neutron star merging with black holes or another neutron star are expected to generate gravitational waves that are slightly weaker but similar to those of black hole-black hole mergers, Foucart said.

Radioactive 'waste' in space

Daniel Kasen, a scientist in the Nuclear Science Division at Berkeley Lab and associate professor of physics and astronomy at UC Berkeley who participated in the research, said that inside neutron stars "there may be exotic states of matter unlike anything realized anywhere else in the universe."

In some computer simulations the neutron stars were swallowed whole by the black hole, while in others there was a fraction of matter coughed up into space. This ejected matter is estimated to range up to about one-tenth of the mass of the sun.

While much of the matter gets sucked into the larger black hole that forms from the merger, "the material that gets flung out eventually turns into a kind of radioactive 'waste,'" he said. "You can see the radioactive glow of that material for a period of days or weeks, from more than a hundred million light years away." Scientists refer to this observable radioactive glow as a "kilonova."

The simulations use different sets of calculations to help scientists visualize how matter escapes from these mergers. By modeling the speed, trajectory, amount and type of matter, and even the color of the light it gives off, astrophysicists can learn how to track down actual events.

The weird world of neutron stars

The size range of neutron stars is set by the ultimate limit on how densely matter can be compacted, and neutron stars are among the most superdense objects we know about in the universe.

Neutron stars have been observed to have masses up to at least two times that of our sun but measure only about 12 miles in diameter, on average, while our own sun has a diameter of about 865,000 miles. At large enough masses, perhaps about three times the mass of the sun, scientists expect that neutron stars must collapse to form black holes.

A cubic inch of matter from a neutron star is estimated to weigh up to 10 billion tons. As their name suggests, neutron stars are thought to be composed largely of the neutrally charged subatomic particles called neutrons, and some models expect them to contain long strands of matter -- known as "nuclear pasta" -- formed by atomic nuclei that bind together.

Neutron stars are also expected to be almost perfectly spherical, with a rigid and incredibly smooth crust and an ultrapowerful magnetic field. They can spin at a rate of about 43,000 revolutions per minute (RPMs), or about five times faster than a NASCAR race car engine's RPMs.

The aftermath of neutron star mergers

The researchers' simulations showed that the radioactive matter that first escapes the black hole mergers may be traveling at speeds of about 20,000 to 60,000 miles per second, or up to about one-third the speed of light, as it is swung away in a long "tidal tail."

"This would be strange material that is loaded with neutrons," Kasen said. "As that expanding material cools and decompresses, the particles may be able to combine to build up into the heaviest elements." This latest research shows how scientists might find these bright bundles of heavy elements.

"If we can follow up LIGO detections with telescopes and catch a radioactive glow, we may finally witness the birthplace of the heaviest elements in the universe," he said. "That would answer one of the longest-standing questions in astrophysics."

Most of the matter in a black hole-neutron star merger is expected to be sucked up by the black hole within a millisecond of the merger, and other matter that is not flung away in the merger is likely to form an extremely dense, thin, donut-shaped halo of matter.

The thin, hot disk of matter that is bound by the black hole is expected to form within about 10 milliseconds of the merger, and to be concentrated within about 15 to 70 miles of it, the simulations showed. This first 10 milliseconds appears to be key in the long-term evolution of these disks.

Over timescales ranging from tens of milliseconds to several seconds, the hot disk spreads out and launches more matter into space. "A number of physical processes -- from magnetic fields to particle interactions and nuclear reactions -- combine in complex ways to drive the evolution of the disk," said Rodrigo Fernández, an assistant professor of physics at the University of Alberta in Canada who led one of the studies.

Simulations carried out on NERSC's Edison supercomputer were crucial in understanding how the disk ejects matter and in providing clues for how to observe this matter, said Fernández, a former UC Berkeley postdoctoral researcher.

What's next?

Eventually, it may be possible for astronomers scanning the night sky to find the "needle in a haystack" of radioactive kilonovae from neutron star mergers that had been missed in the LIGO data, Kasen said.

"With improved models, we are better able to tell the observers exactly which flashes of light are the signals they are looking for," he said. Kasen is also working to build increasingly sophisticated models of neutron star mergers and supernovae through his involvement in the DOE Exascale Computing Project.

Read more at Science Daily

First civilizations of Greece are revealing their stories to science

Bull-leaping fresco, Knossos palace, Crete, Greece.

For the first time, scientists have obtained and analyzed genome sequences from the ancient Minoans and Mycenaeans, who lived three to five thousand years ago and were Europe's first civilized people.

The new analysis suggests that the Minoans and Mycenaeans share a great deal of their genetic heritage, Howard Hughes Medical Institute (HHMI) investigator David Reich and colleagues report August 2 in the journal Nature. The research adds richness to our understanding of these cultures, which are mostly known from archeology and ancient literature, Reich says.

"Who these Bronze Age peoples were -- the people who lived in a world dimly remembered in the poetry of Homer -- has been a great mystery," explains Reich, an evolutionary geneticist at Harvard Medical School. "We set out to investigate the origins of these ancient civilizations."

Their origins have been intensely debated. Theories include migrations from various locations, including Europe and Asia Minor, and at various times before and during the Bronze Age. Both cultures were literate and had writing, but the Minoan language hasn't been deciphered. The Mycenaean language, an early form of Greek, is part of the Indo-European language family, whose languages have been spoken across Europe and central and southern Asia since the beginning of recorded history. The identity of the Minoan language is unknown. But despite extensive archeological and linguistic research, the origins of both cultures and their relationship to each other and to other Bronze Age peoples have remained a puzzle.

Reich and his colleagues' work suggests that about three-quarters of the ancestry of both peoples derives from the first farmers of the Aegean Sea, including western Anatolia (a region that lies within modern day Turkey), Greece, and the Greek islands. But, quite different from the rest of contemporary Europe and from the first farmers of Greece, the Bronze Age Greek civilizations also derived a small part of their ancestry from populations from the Caucasus and Iran.

The Minoans, based on the island of Crete from roughly 3100 to 1050 BCE, were a maritime people with sophisticated palaces, one of which was so large and complex that it may have been the historical basis of the myth of the Labyrinth, home of the beast called the Minotaur. The Mycenaeans of mainland Greece, 1700 to 1100 BCE, who eventually conquered the Minoans, were skilled engineers and fierce warriors. Their culture is named for Mycenae, a site with a fortified palace that was the seat of the celebrated King Agamemnon, who led the Greeks in the Trojan War.

Reich and his colleagues at the Max Planck Institute in Jena, Germany and the University of Washington teamed up with Greek and Turkish archeologists and anthropologists to obtain samples from 19 Bronze Age individuals excavated from tombs and other sites throughout the Aegean. The ancient DNA, carefully extracted from bones and teeth, included 10 Minoans, four Mycenaeans, three individuals from southwest Anatolia (Turkey), an individual from Crete that dates from after the arrival of the Mycenaeans on the island, and one Neolithic sample (5,400 BCE) from the mainland that predated the emergence of the Greek civilizations. The researchers then compared and contrasted the new DNA samples with previously reported data from 332 other ancient individuals, 2,614 present-day humans, and two present-day Cretans.

The new study also shows that the Mycenaeans have additional ancestry that is distinct from the Minoans, says Iosif Lazaridis, a postdoctoral researcher in Reich's lab and lead author of the study. This genetic contribution may be from people of the steppes north of the Black and Caspian seas.

Scholars have debated whether the Indo-European language, which gave rise to Italic, Germanic, Slavic and Hindi languages, among others, spread with migrations from Anatolia or from the steppe. Previous work by Reich and colleagues supports the "steppe hypothesis." Their latest data suggest that the speakers of this early Greek language may have formed the southern portion of the same migrations that contributed to the dispersal of other Indo-European languages, Reich says.

Read more at Science Daily

Exoplanet shines with glowing water atmosphere

Researchers have found that a "hot Jupiter" exoplanet named WASP-121b (left) has a stratosphere hot enough to boil iron. The planet is as close to its host star (right) as possible without the star's gravity ripping the planet apart.

Scientists have found compelling evidence for a stratosphere on an enormous planet outside our solar system. The planet's stratosphere -- a layer of atmosphere where temperature increases with higher altitudes -- is hot enough to boil iron. WASP-121b, located approximately 900 light years from Earth, is a gas giant exoplanet commonly referred to as a "hot Jupiter."

An international team of researchers, led by the University of Exeter with contributions from the University of Maryland, made the new discovery by observing glowing water molecules in WASP-121b's atmosphere using NASA's Hubble Space Telescope. The research is published in the August 3, 2017 issue of the journal Nature.

Previous research spanning the past decade has indicated possible evidence for stratospheres on other exoplanets, but this is the first time that glowing water molecules have been detected -- the clearest signal yet to indicate an exoplanet stratosphere.

"When it comes to distant exoplanets, which we can't see in the same detail as other planets here in our own solar system, we have to rely on proxy techniques to reveal their structure," said Drake Deming, a professor of astronomy at UMD and a co-author of the study. "The stratosphere of WASP-121b so hot it can make water vapor glow, which is the basis for our analysis."

To study the gas giant's stratosphere, scientists used spectroscopy to analyze how the planet's brightness changed at different wavelengths of light. Water vapor in the planet's atmosphere, for example, behaves in predictable ways in response to certain wavelengths of light, depending on the temperature of the water. At cooler temperatures, water vapor blocks light from beneath it. But at higher temperatures, the water molecules glow.

The phenomenon is similar to what happens with fireworks, which get their colors when metallic substances are heated and vaporized, moving their electrons into higher energy states. Depending on the material, these electrons will emit light at specific wavelengths as they lose energy. For example, sodium produces orange-yellow light and strontium produces red light.

The water molecules in the atmosphere of WASP-121b similarly give off radiation as they lose energy, but it is in the form of infrared light, which the human eye is unable to detect.

"Theoretical models have suggested that stratospheres may define a special class of ultra-hot exoplanets, with important implications for the atmospheric physics and chemistry," said Tom Evans, research fellow at the University of Exeter and lead author of the study. "When we pointed Hubble at WASP-121b, we saw glowing water molecules, implying that the planet has a strong stratosphere."

WASP-121b has a greater mass and radius than Jupiter, making it much puffier.

The exoplanet orbits its host star every 1.3 days, and the two bodies are about as close as they can be to each other without the star's gravity ripping the planet apart. This close proximity also means that the top of the atmosphere is heated to a blazing hot 2,500 degrees Celsius -- the temperature at which iron exists in gas rather than solid form.

"This new research is the smoking gun evidence scientists have been searching for when studying hot exoplanets," said Professor David Sing, an associate professor of astrophysics at the University of Exeter and a co-author of the research paper. "We have discovered this hot Jupiter has a stratosphere, a common feature seen in most of our solar system planets."

In Earth's stratosphere, ozone traps ultraviolet radiation from the sun, which raises the temperature of this layer of atmosphere. Other solar system bodies have stratospheres, too -- methane is responsible for heating in the stratospheres of Jupiter and Saturn's moon Titan, for example. In solar system planets, the change in temperature within a stratosphere is typically less than 100 degrees Celsius. However, on WASP-121b, the temperature in the stratosphere rises by 1,000 degrees Celsius.

"We've measured a strong rise in the temperature of WASP-121b's atmosphere at higher altitudes, but we don't yet know what's causing this dramatic heating," said Nikolay Nikolov, co-author and research fellow at the University of Exeter. "We hope to address this mystery with upcoming observations at other wavelengths."

Vanadium oxide and titanium oxide gases are candidate heat sources, as they strongly absorb starlight at visible wavelengths, much like ozone absorbs UV radiation. These compounds are expected to be present in only the hottest of hot Jupiters, such as WASP-121b, as high temperatures are required to keep them in the gaseous state. Indeed, vanadium oxide and titanium oxide are commonly seen in brown dwarfs, 'failed stars' that have some commonalities with exoplanets.

Read more at Science Daily

Rare Conjoined Bat Twins Discovered in Brazil

Conjoined bat twins found in Brazil.

When Marcelo Rodrigues Nogueira, a postdoctoral researcher in biology at the State University of Northern Rio de Janeiro first saw the bat twins, he was "completely astonished," he wrote in an email to Live Science. "I have handled many bats [in my career], some with very impressive morphological characters (and bats are very special in this respect!), but none [were as] surprising as these twins." [See Photos of the Rare Conjoined Bats Found in Brazil]

Only two other pairs of conjoined bat twins have been reported in the scientific literature, one in 1969 and another in 2015.

Although it's not known exactly what causes identical twins to be conjoined, the phenomenon is known to occur when a fertilized egg splits too late. If an egg splits four to five days after being fertilized, two separate identical twins will form. If, however, the splitting doesn't occur until 13 to 15 days after fertilization, the fertilized egg will only separate partially, and the twins will be conjoined.

The researchers first became aware of the conjoined bats after the animals were donated to the Laboratory of Mastozoology at the Rural Federal University of Rio de Janeiro. No one from Nogueira's team, which includes embryologists Nadja Lima Pinheiro and Adriana Ventura from the Area of Embryology at the Rural Federal University of Rio de Janeiro, saw the twins right when they were found. Because of this, the scientists, aren't certain if the twins were stillborn or if they had died shortly after birth.

This X-ray shows that the spines of the conjoined bat twins are joined at their lower backs.

The bats, found under a mango tree in southeastern Brazil in 2001, are dicephalic parapagus conjoined twins, which means they're oriented side by side with their whole trunks conjoined. X-rays revealed that the twins' spines form a "Y" shape, with two separate columns of vertebrae branching off at the lower back. Ultrasound images also revealed two hearts of equal size that researchers suspect are separate, the scientists said.

Since most bats have only one pup per litter, finding even nonconjoined bat twins is rare. In the five years Daniel Urban, a postdoctoral research associate in evolutionary developmental biology at the University of Illinois at Urbana-Champaign, has been studying bats, he's only ever seen a single pup flying around or hanging onto its mother, he told Live Science. Urban was the lead author of the 2015 study on conjoined bat twins that was published in the journal Acta Chiropterologica.

It's even harder to find bat twins that are conjoined. But this doesn't mean conjoined twins are rarer in bats than in any other mammals, according to Scott Pedersen, a professor of biology and microbiology at South Dakota State University, who was not involved in the new study. It's just that humans find out about conjoined bats less often than they find out about other conjoined animals, he told Live Science in an email.

Even if conjoined bats are alive when they are born, it's likely that they'll die soon after, because their bodies can't sustain them, Pedersen said. Bats also tend to live in places humans aren't located, which means even if a person were to venture into a bat's domain, the person would need to find the conjoined bats before they degraded or were scavenged.

This is only made more unlikely by the fact that bats are nocturnal, said Urban. If a mother gives birth to conjoined bats during the day, it will likely be in a protected roost, which means people wouldn't see them. She may give birth while she's out in the open, but that would occur only at night, when the twins would be obscured by darkness, Urban said.

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Scientists watch 'artificial atoms' assemble into perfect lattices with many uses

An illustration shows nanocrystals assembling into an ordered ‘superlattice’ – a process that a SLAC/Stanford team was able to observe in real time with X-rays from the Stanford Synchrotron Radiation Lightsource (SSRL). They discovered that this assembly takes just a few seconds when carried out in hot solutions. The results open the door for rapid self-assembly of nanocrystal building blocks into complex structures with applications in optoelectronics, solar cells, catalysis and magnetic materials.

Some of the world's tiniest crystals are known as "artificial atoms" because they can organize themselves into structures that look like molecules, including "superlattices" that are potential building blocks for novel materials.

Now scientists from the Department of Energy's SLAC National Accelerator Laboratory and Stanford University have made the first observation of these nanocrystals rapidly forming superlattices while they are themselves still growing. What they learn will help scientists fine-tune the assembly process and adapt it to make new types of materials for things like magnetic storage, solar cells, optoelectronics and catalysts that speed chemical reactions.

The key to making it work was the serendipitous discovery that superlattices can form superfast -- in seconds rather than the usual hours or days -- during the routine synthesis of nanocrystals. The scientists used a powerful beam of X-rays at SLAC's Stanford Synchrotron Radiation Lightsource (SSRL) to observe the growth of nanocrystals and the rapid formation of superlattices in real time.

A paper describing the research, which was done in collaboration with scientists at the DOE's Argonne National Laboratory, was published today in Nature.

"The idea is to see if we can get an independent understanding of how these superlattices grow so we can make them more uniform and control their properties," said Chris Tassone, a staff scientist at SSRL who led the study with Matteo Cargnello, assistant professor of chemical engineering at Stanford

Tiny Crystals with Outsized Properties

Scientists have been making nanocrystals in the lab since the 1980s. Because of their tiny size -they're billionths of a meter wide and contain just 100 to 10,000 atoms apiece -- they are governed by the laws of quantum mechanics, and this gives them interesting properties that can be changed by varying their size, shape and composition. For instance, spherical nanocrystals known as quantum dots, which are made of semiconducting materials, glow in colors that depend on their size; they are used in biological imaging and most recently in high-definition TV displays.

In the early 1990s, researchers started using nanocrystals to build superlattices, which have the ordered structure of regular crystals, but with small particles in place of individual atoms. These, too, are expected to have unusual properties that are more than the sum of their parts.

But until now, superlattices have been grown slowly at low temperatures, sometimes in a matter of days.

That changed in February 2016, when Stanford postdoctoral researcher Liheng Wu serendipitously discovered that the process can occur much faster than scientists had thought.

'Something Weird Is Happening'

He was trying to make nanocrystals of palladium -- a silvery metal that's used to promote chemical reactions in catalytic converters and many industrial processes -- by heating a solution containing palladium atoms to more than 230 degrees Celsius. The goal was to understand how these tiny particles form, so their size and other properties could be more easily adjusted.

The team added small windows to a reaction chamber about the size of a tangerine so they could shine an SSRL X-ray beam through it and watch what was happening in real time.

"It's kind of like cooking," Cargnello explained. "The reaction chamber is like a pan. We add a solvent, which is like the frying oil; the main ingredients for the nanocrystals, such as palladium; and condiments, which in this case are surfactant compounds that tune the reaction conditions so you can control the size and composition of the particles. Once you add everything to the pan, you heat it up and fry your stuff."

Wu and Stanford graduate student Joshua Willis expected to see the characteristic pattern made by X-rays scattering off the tiny particles.They saw a completely different pattern instead.

"So something weird is happening," they texted their advisor.

The something weird was that the palladium nanocrystals were assembling into superlattices.

A Balance of Forces

At this point, "The challenge was to understand what brings the particles together and attracts them to each other but not too strongly, so they have room to wiggle around and settle into an ordered position," said Jian Qin, an assistant professor of chemical engineering at Stanford who performed theoretical calculations to better understand the self-assembly process.

Once the nanocrystals form, what seems to be happening is that they acquire a sort of hairy coating of surfactant molecules. The nanocrystals glom together, attracted by weak forces between their cores, and then a finely tuned balance of attractive and repulsive forces between the dangling surfactant molecules holds them in just the right configuration for the superlattice to grow.

To the scientists' surprise, the individual nanocrystals then kept on growing, along with the superlattices, until all the chemical ingredients in the solution were used up, and this unexpected added growth made the material swell. The researchers said they think this occurs in a wide range of nanocrystal systems, but had never been seen because there was no way to observe it in real time before the team's experiments at SSRL.

Read more at Science Daily

Sun's core rotates four times faster than its surface

The sun is emitting plumes of hydrogen plasma. The white areas are where the sun's magnetic field is especially strong.

The sun's core rotates nearly four times faster than the sun's surface, according to new findings by an international team of astronomers. Scientists had assumed the core was rotating like a merry-go-round at about the same speed as the surface.

"The most likely explanation is that this core rotation is left over from the period when the sun formed, some 4.6 billion years ago," said Roger Ulrich, a UCLA professor emeritus of astronomy, who has studied the sun's interior for more than 40 years and co-author of the study that was published today in the journal Astronomy and Astrophysics. "It's a surprise, and exciting to think we might have uncovered a relic of what the sun was like when it first formed."

The rotation of the solar core may give a clue to how the sun formed. After the sun formed, the solar wind likely slowed the rotation of the outer part of the sun, he said. The rotation might also impact sunspots, which also rotate, Ulrich said. Sunspots can be enormous; a single sunspot can even be larger than the Earth.

The researchers studied surface acoustic waves in the sun's atmosphere, some of which penetrate to the sun's core, where they interact with gravity waves that have a sloshing motion similar to how water would move in a half-filled tanker truck driving on a curvy mountain road. From those observations, they detected the sloshing motions of the solar core. By carefully measuring the acoustic waves, the researchers precisely determined the time it takes an acoustic wave to travel from the surface to the center of the sun and back again. That travel time turns out to be influenced a slight amount by the sloshing motion of the gravity waves, Ulrich said.

The researchers identified the sloshing motion and made the calculations using 16 years of observations from an instrument called GOLF (Global Oscillations at Low Frequency) on a spacecraft called SoHO (the Solar and Heliospheric Observatory) -- a joint project of the European Space Agency and NASA. The method was developed by the researchers, led by astronomer Eric Fossat of the Observatoire de la Côte d'Azur in Nice, France. Patrick Boumier with France's Institut d'Astrophysique Spatiale is GOLF's principal investigator and a co-author of the study.

The idea that the solar core could be rotating more rapidly than the surface has been considered for more than 20 years, but has never before been measured.

The core of the sun differs from its surface in another way as well. The core has a temperature of approximately 29 million degrees Fahrenheit, which is 15.7 million Kelvin. The sun's surface is "only" about 30,000 degrees Fahrenheit, or 5,800 Kelvin.

Ulrich worked with the GOLF science team, analyzing and interpreting the data for 15 years. Ulrich received funding from NASA for his research. The GOLF instrument was funded primarily by the European Space Agency.

Read more at Science Daily

Earth’s First Flower Had Male and Female Parts

The first flower to appear along the path of plant evolution, during the time of the dinosaurs, was a hermaphrodite with petal-like organs arranged in concentric circles, researchers said Monday.

The bloom had both male and female reproductive organs at the center, surrounded by multiple layers or "whorls" of petal-like parts called tepals, arranged in sets of three per layer, they wrote in the journal Nature Communications.

The reconstruction, based on the largest dataset of flower traits ever assembled — from 792 existing species — challenges scientific assumptions that the ancestral flower would have had its sex organs and "petals" arranged in a spiral.

Most flowers today have four "whorls" — the outer leaves or sepals, followed by the petals, which enclose the male organs called stamens, with the female organs or carpels at the center.

The ancestral flower likely did not have separate sepals and petals, instead sporting tepals — a mix between the two — around the sex organs at the center.

Modern flowers with tepals rather than petals include tulips and lilies.

"The results are really exciting," said Maria von Balthazar, a floral morphology expert at the University of Vienna, who took part in the research.

"This is the first time that we have a clear vision for the early evolution of flowers across all angiosperms" — the scientific term for flowering plants.

Maximum likelihood ancestral state reconstruction of functional sex of flowers in angiosperms.

We still do not know the flower's color, what it smelled like, or its size — presumed to have been less than a centimeter (0.4 inches) in diameter.

Experts believe that land plants emerged from ancestral water plants about 470 million years ago — more than three billion years after the first life is thought to have emerged when Earth was about a billion years old.

Tree or shrub

The first seed plant — the group that includes flowering plants and cone-bearing ones — likely emerged about 320 million years ago, when there were diverse animals on land and at sea, but not yet dinosaurs, mammals, or birds.

The oldest-known fossils of flowering plants date from about 140 million years ago — during the age of the dinosaurs, which went extinct some 66 million years ago.

Since then, the first flower has evolved into at least 300,0000 species that include almost all plant types used by people for food, medicine, and other purposes, said the research team.

Flowering plants represent about 90 percent of all plants on Earth.

The ancestral flower of angiosperms and its early diversification.

In 1879, evolutionary scientist Charles Darwin famously described the flower's rapid rise and diversification during the Cretaceous geological era as an "abominable mystery."

The team combined DNA data and a vast library of plant traits to compile a detailed evolutionary tree leading back to the last common ancestor.

Read more at Seeker

A Geoengineering ‘Cocktail’ Could Dull the Pain of Climate Change

Even to advocates of geoengineering the idea of deliberately altering the environment to avoid the worst effects of climate change is laden with risks.

Such meddling could cause unforeseen ecological consequences, they say. And then there are political risks: Researchers fret that even proposing a techno-fix for global warming could lessen the urgency to reduce global emissions of carbon dioxide, the primary driver of global warming, and other greenhouse gases.

Yet the dangers of climate change are becoming more apparent with each passing year. A new study in the journal Nature Climate Change warns that by the 2100, the planet has only a 5 percent chance of limiting temperature rise to 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-Industrial Age levels — a threshold above which many climatologists warn truly scary things will happen to Earth’s atmosphere and oceans.

Forecasts like that make large-scale climate engineering proposals worth studying, says Ken Caldeira, climate researcher at the Carnegie Institution for Science in California.

“Transforming our energy system will take the better part of a century and temperatures are likely to go up substantially while that’s happening,” he said. “If you think there’s a substantial chance of catastrophic outcomes, then solar geoengineering approaches are the only things that could cause the Earth to cool down within a politically relevant timescale.”

Geoengineering, he said, is best understood as a temporary ecological painkiller that could be administered while the world undergoes the difficult surgery of transitioning to a low-carbon economy.

“The consequences of global warming may be so bad that it’s worth doing something as dramatic and risky as deploying these solar geoengineering ideas at large scale,” Caldeira said. “But geoengineering is not a substitute for emissions reduction. It’s a compliment to emissions reduction.”

Yet if such a program were to proceed — which approach should be used?

Caldeira and an international team of researchers from China and India recently proposed a novel idea of combining multiple approaches to create “cocktail geoengineering,” in an attempt to calibrate both temperature changes and fluctuations in precipitation.

Their first ingredient is one of the most prominent ideas in geoengineering — spraying aerosols into the stratosphere to reflect some of the sun’s incoming rays back into space.

Climate models suggest this approach would reduce global rainfall, however, because when beams of sunlight hit the Earth, they warm the oceans and cause evaporation, which in turn falls back down as rain.

Caldeira and his colleagues looked at combining the stratospheric aerosol technique with another approach — thinning high cirrus clouds, which are involved in regulating the amount of heat that escapes from the planet to outer space.

The team found that blending the two techniques would likely reduce global temperatures and maintain global precipitation amounts at their pre-industrial levels.

Yet the climate model examined by Caldeira and his team has an unresolved drawback, he said. The overall level of precipitation would stabilize, but rainfall would likely be redistributed around the globe, potentially overrunning some areas and drying out others.

“For every different locality, you wouldn’t do much better using the cocktail than you would just using stratospheric aerosols alone,” Caldeira said.

Nevertheless, Caldeira said climate models suggest geoengineering would be effective at mitigating the worst impacts of climate change for most people — buying time for nations to reduce their greenhouse gas emissions.

“If you actually trusted the models, and you were really concerned about climate damage, then you’d take this very seriously,” he said.

But others who agree on the need to drastically reduce carbon dioxide emissions say that taking geoengineering seriously creates more problems than it solves. Among them is Pat Mooney, executive director of ETC Group, an organization that monitors the introduction of new technologies, especially in underdeveloped countries.

Mooney worries that as geoengineering gains a higher profile, politicians will use it as an excuse not to make the painful economic changes necessary to reduce emissions.

Geoengineering “gives our politicians another excuse not to do anything,” Mooney said by phone from Nova Scotia, Canada. “It doesn’t solve the problem. It just puts another weapon in the hands of incompetent politicians.”

Read more at Seeker

Making dew droplets so small, they're invisible

Essentially, when the nanopillars are tall and slender, the droplets formed inside and on the crevices can jump off the surface at a much smaller size, down to two micrometers. Likewise, short and stout pillars increase the size of the droplet required to jump -- up to 20 micrometers in the case of Mulroe's experiment.

By better understanding the behavior of water in its smallest form, a Virginia Tech professor and his undergraduate student could be improving the efficiency of removing condensation in a major way.

Jonathan Boreyko, an assistant professor in the Department of Biomedical Engineering and Mechanics in the Virginia Tech College of Engineering, has been studying "jumping" dew droplets since he discovered the phenomenon in graduate school.

According to Boreyko, dew droplets only jump from water-repellent surfaces when they reach a large enough size -- about 10 micrometers -- but it was unclear why until Boreyko and his students made a breakthrough discovery, soon to be published in the high-impact journal ACS Nano.

In Boreyko's lab, then-undergraduate Megan Mulroe experimented with the surface of silicon chips to see how the nanoscopic topography of the surface might impact the jumping ability of condensation.

By creating and testing six different types of surfaces covered with so-called nanopillars -- reminiscent of stalagmites on a cave floor -- Mulroe found that the critical size of the jumping droplet can be fine-tuned based on the height, diameter, and pitch of the nanopillars.

"These results, correlated with a theoretical model, revealed that the bottleneck for jumping is how the droplets inflate inside of the surface after they first form," Boreyko said.

Essentially, when the nanopillars are tall and slender, the droplets formed inside and on the crevices can jump off the surface at a much smaller size, down to two micrometers. Likewise, short and stout pillars increase the size of the droplet required to jump -- up to 20 micrometers in the case of Mulroe's experiment.

While the jumping droplets phenomena has been found to be the most efficient form of condensation removal, the ability to tweak the size of the droplets can allow for improved efficiency in removing condensation from surfaces.

"We expect that these findings will allow for maximizing the efficiency of jumping-droplet condensers, which could make power plants more efficient and enable robust anti-fogging and self-cleaning surfaces," Boreyko said. "The ultimate goal is for all dew droplets forming on a surface to jump off before they are even visible to the eye."

Read more at Science Daily