Thursday, October 18, 2018

PrinTracker Can Analyze Machine "Fingerprints" and Help Identify 3D Printed Guns and Counterfeit Products Origins



- Like fingerprints, no 3D printer is exactly the same.

That's the takeaway from a new University at Buffalo-led study that describes what's believed to be the first accurate method for tracing a 3D-printed object to the machine it came from.

The advancement, which the research team calls "PrinTracker," could ultimately help law enforcement and intelligence agencies track the origin of 3D-printed guns, counterfeit products and other goods.

"3D printing has many wonderful uses, but it's also a counterfeiter's dream. Even more concerning, it has the potential to make firearms more readily available to people who are not allowed to possess them," says the study's lead author Wenyao Xu, PhD, associate professor of computer science and engineering in UB's School of Engineering and Applied Sciences.

Photo illustration of how the technology works.
illustration of how the 3D printer fingerprinting technology works
Credit: Wenyao Xu, University at Buffalo

The study will be presented in Toronto at the Association for Computing Machinery's Conference on Computer and Communications Security, which runs from Oct. 15-19. It includes coauthors from Rutgers University and Northeastern University.

To understand the method, it's helpful to know how 3D printers work. Like a common inkjet printer, 3D printers move back-and-forth while "printing" an object. Instead of ink, a nozzle discharges a filament, such as plastic, in layers until a three-dimensional object forms.

Each layer of a 3D-printed object contains tiny wrinkles -- usually measured in submillimeters -- called in-fill patterns. These patterns are supposed to be uniform. However, the printer's model type, filament, nozzle size and other factors cause slight imperfections in the patterns. The result is an object that does not match its design plan.

For example, the printer is ordered to create an object with half-millimeter in-fill patterns. But the actual object has patterns that vary 5 to 10 percent from the design plan. Like a fingerprint to a person, these patterns are unique and repeatable. As a result, they can be traced back to the 3D printer.

"3D printers are built to be the same. But there are slight variations in their hardware created during the manufacturing process that lead to unique, inevitable and unchangeable patterns in every object they print," Xu says.

To test PrinTracker, the research team created five door keys each from 14 common 3D printers -- 10 fused deposition modeling (FDM) printers and four stereolithography (SLA) printers.

With a common scanner, the researchers created digital images of each key. From there, they enhanced and filtered each image, identifying elements of the in-fill pattern. They then developed an algorithm to align and calculate the variations of each key to verify the authenticity of the fingerprint.

Having created a fingerprint database of the 14 3D printers, the researchers were able to match the key to its printer 99.8 percent of the time. They ran a separate series of tests 10 months later to determine if additional use of the printers would affect PrinTracker's ability to match objects to their machine of origin. The results were the same.

The team also ran experiments involving keys damaged in various ways to obscure their identity. PrinTracker was 92 percent accurate in these tests.

Xu likens the technology to the ability to identify the source of paper documents, a practice used by law enforcement agencies, printer companies and other organizations for decades. While the experiments did not involve counterfeit goods or firearms, Xu says PrinTracker can be used to trace any 3D-printed object to its printer.

"We've demonstrated that PrinTracker is an effective, robust and reliable way that law enforcement agencies, as well as businesses concerned about intellectual property, can trace the origin of 3D-printed goods," Xu says.


Contacts and sources:     .
Cory Nealon
University at Buffalo
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New Solar Heat to Electricity Cheap Enough to Compete with Fossil Fuels

Solar power accounts for less than 2 percent of U.S. electricity but could make up more than that if the cost of electricity generation and energy storage for use on cloudy days and at nighttime were cheaper.

A Purdue University-led team developed a new material and manufacturing process that would make one way to use solar power – as heat energy – more efficient in generating electricity.

The innovation is an important step for putting solar heat-to-electricity generation in direct cost competition with fossil fuels, which generate more than 60 percent of electricity in the U.S.

Credit: Purdue University

“Storing solar energy as heat can already be cheaper than storing energy via batteries, so the next step is reducing the cost of generating electricity from the sun's heat with the added benefit of zero greenhouse gas emissions,” said Kenneth Sandhage, Purdue’s Reilly Professor of Materials Engineering.

The research, which was done at Purdue in collaboration with the Georgia Institute of Technology, the University of Wisconsin-Madison and Oak Ridge National Laboratory, published in the journal Nature
S
A recent development would make electricity generation from the sun's heat more efficient, by using ceramic-metal plates for heat transfer at higher temperatures and at elevated pressures.
 Purdue University illustration/Raymond Hassan

This work aligns with Purdue's Giant Leaps celebration, acknowledging the university’s global advancements made for a sustainable economy and planet as part of Purdue’s 150th anniversary. This is one of the four themes of the yearlong celebration’s Ideas Festival, designed to showcase Purdue as an intellectual center solving real-world issues.

Solar power doesn't only generate electricity via panels in farms or on rooftops. Another option is concentrated power plants that run on heat energy.

Concentrated solar power plants convert solar energy into electricity by using mirrors or lenses to concentrate a lot of light onto a small area, which generates heat that is transferred to a molten salt. Heat from the molten salt is then transferred to a "working" fluid, supercritical carbon dioxide, that expands and works to spin a turbine for generating electricity.

To make solar-powered electricity cheaper, the turbine engine would need to generate even more electricity for the same amount of heat, which means the engine needs to run hotter.

The problem is that heat exchangers, which transfer heat from the hot molten salt to the working fluid, are currently made of stainless steel or nickel-based alloys that get too soft at the desired higher temperatures and at the elevated pressure of supercritical carbon dioxide.

Inspired by the materials his group had previously combined to make "composite" materials that can handle high heat and pressure for applications like solid-fuel rocket nozzles, Sandhage worked with Asegun Henry, now at the Massachusetts Institute of Technology, to conceive of a similar composite for more robust heat exchangers.

Two materials showed promise together as a composite: The ceramic zirconium carbide, and the metal tungsten.

Purdue researchers created plates of the ceramic-metal composite. The plates host customizable channels for tailoring the exchange of heat, based on simulations of the channels conducted at Georgia Tech by Devesh Ranjan's team.

Mechanical tests by Edgar Lara-Curzio’s team at Oak Ridge National Laboratory and corrosion tests by Mark Anderson’s team at Wisconsin-Madison helped show that this new composite material could be tailored to successfully withstand the higher temperature, high-pressure supercritical carbon dioxide needed for generating electricity more efficiently than today’s heat exchangers.

An economic analysis by Georgia Tech and Purdue researchers also showed that the scaled-up manufacturing of these heat exchangers could be conducted at comparable or lower cost than for stainless steel or nickel alloy-based ones.

“Ultimately, with continued development, this technology would allow for large-scale penetration of renewable solar energy into the electricity grid,” Sandhage said. “This would mean dramatic reductions in man-made carbon dioxide emissions from electricity production.”

A patent application has been filed for this advancement. The work is supported by the U.S. Department of Energy, which has also recently awarded additional funding for further development and scaling up the technology.

Contacts and sources: 
Kayla Wiles / Kenneth Sandhage
Purdue University


Citation: Ceramic–metal composites for heat exchangers in concentrated solar power plants
M. Caccia, M. Tabandeh-Khorshid, G. Itskos, A. R. Strayer, A. S. Caldwell, S. Pidaparti, S. Singnisai, A. D. Rohskopf, A. M. Schroeder, D. Jarrahbashi, T. Kang, S. Sahoo, N. R. Kadasala, A. Marquez-Rossy, M. H. Anderson, E. Lara-Curzio, D. Ranjan, A. Henry, K. H. Sandhage. . Nature, 2018; 562 (7727): 406 DOI: 10.1038/s41586-018-0593-1     .




Cuttlefish Camouflage: Wearing Thoughts on the Skin and Biological Invisibility


Computational image analysis of behaving cuttlefish reveals principles of control and development of a biological invisibility cloak

The unique ability of cuttlefish, squid and octopuses to hide by imitating the colors and texture of their environment has fascinated natural scientists since the time of Aristotle. Uniquely among all animals, these mollusks control their appearance by the direct action of neurons onto expandable pixels, numbered in millions, located in their skin. Scientists at the Max Planck Institute for Brain Research and the Frankfurt Institute for Advanced Studies/Goethe University used this neuron-pixel correspondence to peer into the brain of cuttlefish, inferring the putative structure of control networks through analysis of skin pattern dynamics.


A common cuttlefish (Sepia officinalis)
Credit: © MPI for Brain Research / Stephan Junek

Cuttlefish, squid and octopus are a group of marine mollusks called coleoid cephalopods that once included ammonites, today only known as spiral fossils of the Cretaceous era. Modern coleoid cephalopods lost their external shells about 150 million years ago and took up an increasingly active predatory lifestyle. This development was accompanied by a massive increase in the size of their brains: modern cuttlefish and octopus have the largest brains (relative to body size) among invertebrates with a size comparable to that of reptiles and some mammals. They use these large brains to perform a range of intelligent behaviors, including the singular ability to change their skin pattern to camouflage, or hide, in their surroundings.

Cephalopods control camouflage by the direct action of their brain onto specialized skin cells called chromatophores, that act as biological color “pixels” on a soft skin display. Cuttlefish possess up to millions of chromatophores, each of which can be expanded and contracted to produce local changes in skin contrast. By controlling these chromatophores, cuttlefish can transform their appearance in a fraction of a second. They use camouflage to hunt, to avoid predators, but also to communicate.

To camouflage, cuttlefish do not match their local environment pixel by pixel. Instead, they seem to extract, through vision, a statistical approximation of their environment, and use these heuristics to select an adaptive camouflage out of a presumed large but finite repertoire of likely patterns, selected by evolution. The biological solutions to this statistical-matching problem are unknown. But because cuttlefish can solve it as soon as they hatch out of their egg, their solutions are probably innate, embedded in the cuttlefish brain and relatively simple. A team of scientists at the Max Planck Institute for Brain Research and at the Frankfurt Institute for Advanced Studies (FIAS)/Goethe University, led by MPI Director Gilles Laurent, developed techniques that begin to reveal those solutions.

Cuttlefish chromatophores are specialized cells containing an elastic sack of colored pigment granules. Each chromatophore is attached to minute radial muscles, themselves controlled by small numbers of motor neurons in the brain. When these motor neurons are activated, they cause the muscles to contract, expanding the chromatophore and displaying the pigment. When neural activity ceases, the muscles relax, the elastic pigment sack shrinks back, and the reflective underlying skin is revealed. Because single chromatophores receive input from small numbers of motor neurons, the expansion state of a chromatophore could provide an indirect measurement of motor neuron activity.

“We set out to measure the output of the brain simply and indirectly by imaging the pixels on the animal’s skin” says Laurent. Indeed, monitoring cuttlefish behavior with chromatophore resolution provided a unique opportunity to indirectly ‘image’ very large populations of neurons in freely behaving animals. Postdoc Sam Reiter from the Laurent Lab, the first author of this study, and his coauthors inferred motor neuron activity by analyzing the details of chromatophore co-fluctuations. In turn, by analyzing the co-variations of these inferred motor neurons, they could predict the structure of yet higher levels of control, ‘imaging’ increasingly more deeply into the cuttlefish brain through detailed statistical analysis of its chromatophore output.

Credit: © Nature

Cuttlefish: Wearing thoughts on the skin

A new technique is allowing researchers to study the inner workings of a cuttlefish brain by tracking colour changing cells in their skin. These cell are directly controlled by neurons extending from the brain. By monitoring the cells with high resolution cameras, researchers can track the activity tens of thousands of neurons at once for the first time.

Getting there took many years of hard work, some good insights and a few lucky breaks. A key requirement for success was to manage to track tens of thousands of individual chromatophores in parallel at 60 high-resolution images per second and to track every chromatophore from one image to the next, from one pattern to the next, from one week to the next, as the animal breathed, moved, changed appearance and grew, constantly inserting new chromatophores. One key insight was “realizing that the physical arrangement of chromatophores on the skin is irregular enough that it is locally unique, thus providing local fingerprints for image stitching” says Matthias Kaschube of FIAS/GU. By iterative and piecewise image comparison, it became possible to warp images such that all the chromatophores were properly aligned and trackable, even when their individual sizes differed —as occurs when skin patterns change— and even when new chromatophores had appeared —as happens from one day to the next as the animal grows. 

 
Credit: nature video
With insights such as this one, and aided by multiple supercomputers, Laurent’s team managed to meet their goal and with this, started peering into the brain of the animal and its camouflage control system. Along the way, they also made unexpected observations. For example, when an animal changes appearance, it changes in a very specific manner through a sequence of precisely determined intermediate patterns. This observation is important because it suggests internal constraints on pattern generation, thus revealing hidden aspects of the neural control circuits. They also found that chromatophores systematically change colors over time, and that the time necessary for this change is matched to the rate of production of new chromatophores as the animal grows, such that the relative fraction of each color remains constant. Finally, from observing this development they derived minimal rules that may explain skin morphogenesis in this and possibly all other species of coleoid cephalopods.

“This study opens up a large range of new questions and opportunities”, says Laurent. “Some of these concern texture perception and are relevant to the growing field of cognitive computational neuroscience; others help define the precise link between brain activity and behavior, a field called neuroethology; others yet help identify the cellular rules of development involved in tissue morphogenesis. Finally, this work opens a window into the brain of animals whose lineage split from ours over 540 million years ago. Cephalopod brains offer a unique opportunity to study the evolution of another form of intelligence, based on a history entirely independent of the vertebrate lineage for over half a billion years”.



Contacts and sources: 
Dr. Arjan Vink
Max-Planck-Gesellschaft


Citation: Elucidating the control and development of skin patterning in cuttlefish
Sam Reiter, Philipp Hülsdunk, Theodosia Woo, Marcel A. Lauterbach, Jessica S. Eberle, Leyla Anne Akay, Amber Longo, Jakob Meier-Credo, Friedrich Kretschmer, Julian D. Langer, Matthias Kaschube, Gilles Laurent. . Nature, 2018; 562 (7727): 361 DOI: 10.1038/s41586-018-0591-3    .



Smartphone Tool Measures Users Alertness on the Job

Our level of alertness rises and falls over the course of a workday, sometimes causing our energy to drop and our minds to wander just as we need to perform important tasks.
To help understand these patterns and improve productivity, Cornell researchers have developed a tool that tracks alertness by measuring pupil size, captured through a burst of photographs taken every time users unlock their smartphones.
“Since our alertness fluctuates, if we can find a pattern it will be very useful to manage and schedule our day,” said Vincent W.S. Tseng, a doctoral student in information science and lead author of “AlertnessScanner: What Do Your Pupils Tell About Your Alertness,” presented in September at the 20th International Conference on Human-Computer Interaction with Mobile Devices and Services.
Traditional methods of analyzing alertness tend to be cumbersome, often including devices that must be worn. Researchers in Cornell’s People-Aware Computing Lab, run by Tanzeem Choudhury, associate professor of information science and senior author on the study, wanted to create a way to measure alertness unobtrusively and continuously.
File:Pupil - eye.jpg

“Since people use their phones very frequently during the day, we were thinking we could use phones as an instrument to understand and measure their alertness,” Tseng said. “And since people’s eyes are affected by their alertness, we were thinking that when people are looking at their phones, we could use a moment to measure their alertness at that point.”
When people are alert, the sympathetic nervous system causes the pupils to dilate to make it easier to take in information. When they’re drowsy, the parasympathetic nervous system causes the pupils to contract.
The paper, co-authored with Saeed Abdullah, an assistant professor in the College of Information Sciences and Technology at Pennsylvania State University, and Cornell information science doctoral student Jean Costa, included two studies conducted over two years. The first study analyzed results from 15 users, who were prompted to take photos of themselves every three hours. Their smartphones needed to have their infrared filters removed to make it easier to detect the contours of the pupil and the iris, particularly for people with dark eyes. The participants were also asked to complete a sleep journal, reporting how many hours they’d slept each night, and to take a phone-based Psychomotor Vigilance Test (PVT) – a five-minute quiz to gauge their reaction time – six times a day.
The photos gave researchers a view of participants’ eyes that they then used to measure pupil size, making allowances for position and lighting, in order to predict a person’s reaction time. This was then compared to the results from the PVT.
The researchers found that the pupil-scanning reliably predicted alertness. But because asking people to remove their phones’ infrared filters was impractical, and prompting them to take photos of themselves throughout the day was too obtrusive, they conducted a second study a year later, when smartphone camera quality had improved enough that they no longer needed to remove the filters.
In that second study, eight participants were given smartphones with high-resolution front-facing cameras that took a burst of 30 photos in one second whenever the phones were unlocked. Users also completed the sleep journal and took the PVTs.
Though the two studies were difficult to compare because of their different methods, both showed that pupil scanning was a reliable means of predicting alertness. The second study, which took the photos passively in a burst, was deemed more practical because it required less work by the user, Tseng said.
Tseng said the AlertnessScanner could be particularly useful in health care, since medical professionals often work long hours doing intricate and important work. For example, clinicians typically look at devices during surgery, and a front-facing camera on the devices could track their alertness throughout procedures.
But understanding alertness patterns could be helpful to people in many kinds of workplaces, Tseng said.
“If you want to get something very important done, then probably you should execute this task while you’re at the peak of your alertness; when you’re in a valley of your alertness, you can do something like rote work,” he said. “You’ll also know the best time to take a break in order to allow your alertness or energy to go back up again.”
The research was partly supported by Intel and the Semiconductor Research Corporation, through a Circadian-Rhythm Aware Computing grant.



Contacts and sources:     .
Melanie Lefkowitz / Jeff Tyson
Cornell University

      .



Why The Enhanced Computing Power of The Human Brain



Neurons in the human brain receive electrical signals from thousands of other cells, and long neural extensions called dendrites play a critical role in incorporating all of that information so the cells can respond appropriately.

Using hard-to-obtain samples of human brain tissue, MIT neuroscientists have now discovered that human dendrites have different electrical properties from those of other species. Their studies reveal that electrical signals weaken more as they flow along human dendrites, resulting in a higher degree of electrical compartmentalization, meaning that small sections of dendrites can behave independently from the rest of the neuron.

These differences may contribute to the enhanced computing power of the human brain, the researchers say.

MIT neuroscientists can now record electrical activity from the dendrites of human neurons.
MIT neuroscientists can now record electrical activity from the dendrites of human neurons.
Image: Lou Beaulieu-Laroche and Mark Harnett

“It’s not just that humans are smart because we have more neurons and a larger cortex. From the bottom up, neurons behave differently,” says Mark Harnett, the Fred and Carole Middleton Career Development Assistant Professor of Brain and Cognitive Sciences. “In human neurons, there is more electrical compartmentalization, and that allows these units to be a little bit more independent, potentially leading to increased computational capabilities of single neurons.”

Harnett, who is also a member of MIT’s McGovern Institute for Brain Research, and Sydney Cash, an assistant professor of neurology at Harvard Medical School and Massachusetts General Hospital, are the senior authors of the study, which appears in the Oct. 18 issue of Cell. The paper’s lead author is Lou Beaulieu-Laroche, a graduate student in MIT’s Department of Brain and Cognitive Sciences.

Neural computation

Dendrites can be thought of as analogous to transistors in a computer, performing simple operations using electrical signals. Dendrites receive input from many other neurons and carry those signals to the cell body. If stimulated enough, a neuron fires an action potential — an electrical impulse that then stimulates other neurons. Large networks of these neurons communicate with each other to generate thoughts and behavior.

The structure of a single neuron often resembles a tree, with many branches bringing in information that arrives far from the cell body. Previous research has found that the strength of electrical signals arriving at the cell body depends, in part, on how far they travel along the dendrite to get there. As the signals propagate, they become weaker, so a signal that arrives far from the cell body has less of an impact than one that arrives near the cell body.

Dendrites in the cortex of the human brain are much longer than those in rats and most other species, because the human cortex has evolved to be much thicker than that of other species. In humans, the cortex makes up about 75 percent of the total brain volume, compared to about 30 percent in the rat brain.

Although the human cortex is two to three times thicker than that of rats, it maintains the same overall organization, consisting of six distinctive layers of neurons. Neurons from layer 5 have dendrites long enough to reach all the way to layer 1, meaning that human dendrites have had to elongate as the human brain has evolved, and electrical signals have to travel that much farther.

In the new study, the MIT team wanted to investigate how these length differences might affect dendrites’ electrical properties. They were able to compare electrical activity in rat and human dendrites, using small pieces of brain tissue removed from epilepsy patients undergoing surgical removal of part of the temporal lobe. In order to reach the diseased part of the brain, surgeons also have to take out a small chunk of the anterior temporal lobe.

With the help of MGH collaborators Cash, Matthew Frosch, Ziv Williams, and Emad Eskandar, Harnett’s lab was able to obtain samples of the anterior temporal lobe, each about the size of a fingernail.

Evidence suggests that the anterior temporal lobe is not affected by epilepsy, and the tissue appears normal when examined with neuropathological techniques, Harnett says. This part of the brain appears to be involved in a variety of functions, including language and visual processing, but is not critical to any one function; patients are able to function normally after it is removed.

Once the tissue was removed, the researchers placed it in a solution very similar to cerebrospinal fluid, with oxygen flowing through it. This allowed them to keep the tissue alive for up to 48 hours. During that time, they used a technique known as patch-clamp electrophysiology to measure how electrical signals travel along dendrites of pyramidal neurons, which are the most common type of excitatory neurons in the cortex.

These experiments were performed primarily by Beaulieu-Laroche. Harnett’s lab (and others) have previously done this kind of experiment in rodent dendrites, but his team is the first to analyze electrical properties of human dendrites.


Using hard-to-obtain samples of human brain tissue, McGovern and MGH researchers have now discovered that human dendrites have different electrical properties from those of other species. These differences may contribute to the enhanced computing power of the human brain, the researchers say.

Credit: MIT

Unique features

The researchers found that because human dendrites cover longer distances, a signal flowing along a human dendrite from layer 1 to the cell body in layer 5 is much weaker when it arrives than a signal flowing along a rat dendrite from layer 1 to layer 5.

They also showed that human and rat dendrites have the same number of ion channels, which regulate the current flow, but these channels occur at a lower density in human dendrites as a result of the dendrite elongation. They also developed a detailed biophysical model that shows that this density change can account for some of the differences in electrical activity seen between human and rat dendrites, Harnett says.

Nelson Spruston, senior director of scientific programs at the Howard Hughes Medical Institute Janelia Research Campus, described the researchers’ analysis of human dendrites as “a remarkable accomplishment.”

“These are the most carefully detailed measurements to date of the physiological properties of human neurons,” says Spruston, who was not involved in the research. “These kinds of experiments are very technically demanding, even in mice and rats, so from a technical perspective, it’s pretty amazing that they’ve done this in humans.”

The question remains, how do these differences affect human brainpower? Harnett’s hypothesis is that because of these differences, which allow more regions of a dendrite to influence the strength of an incoming signal, individual neurons can perform more complex computations on the information.

“If you have a cortical column that has a chunk of human or rodent cortex, you’re going to be able to accomplish more computations faster with the human architecture versus the rodent architecture,” he says.

There are many other differences between human neurons and those of other species, Harnett adds, making it difficult to tease out the effects of dendritic electrical properties. In future studies, he hopes to explore further the precise impact of these electrical properties, and how they interact with other unique features of human neurons to produce more computing power.

The research was funded by the National Sciences and Engineering Research Council of Canada, the Dana Foundation David Mahoney Neuroimaging Grant Program, and the National Institutes of Health.


Contacts and sources: 
Anne Trafton 
Massachusetts Institute of Technology


Newly Identified Piranha-Like Jurassic Era Denizen Now Earliest Known Flesh Eating Fish

Jurassic era fish is first known meat eater.

This image shows a new piranha-like fish from Jurassic seas with sharp, pointed teeth that probably fed on the fins of other fishes. From the time of dinosaurs and from the same deposits that contained Archaeopteryx, scientists recovered both this flesh-tearing fish and its scarred prey.

Credit: M. Ebert and T. Nohl


Researchers reporting in Current Biology on October 18 have described a remarkable new species of fish that lived in the sea about 150 million years ago in the time of the dinosaurs. The new species of bony fish had teeth like a piranha, which the researchers suggest they used as piranhas do: to bite off chunks of flesh from other fish.

As further support for that notion, the researchers also found the victims: other fish that had apparently been nibbled on in the same limestone deposits in South Germany (the quarry of Ettling in the Solnhofen region) where this piranha-like fish was found.

"We have other fish from the same locality with chunks missing from their fins," says David Bellwood of James Cook University, Australia. "This is an amazing parallel with modern piranhas, which feed predominantly not on flesh but the fins of other fishes. It's a remarkably smart move as fins regrow, a neat renewable resource. Feed on a fish and it is dead; nibble its fins and you have food for the future."

The newly described fish is part of the world famous collections in the Jura-Museum in Eichstätt. It comes from the same limestone deposits that contained Archaeopteryx.

Careful study of the fossilized specimen's well-preserved jaws revealed long, pointed teeth on the exterior of the vomer, a bone forming the roof of the mouth, and at the front of both upper and lower jaws. Additionally, there are triangular teeth with serrated cutting edges on the prearticular bones that lie along the side of the lower jaw.

The tooth pattern and shape, jaw morphology, and mechanics suggest a mouth equipped to slice flesh or fins, the international team of researchers report. The evidence points to the possibility that the early piranha-like fish may have exploited aggressive mimicry in a striking parallel to the feeding patterns of modern piranha.

This illustration shows an artist's reconstruction of the piranha-like fish.

Credit: The Jura-Museum, Eischstatt, Germany
"We were stunned that this fish had piranha-like teeth," says Martina Kölbl-Ebert of Jura-Museum Eichstätt (JME-SNSB). "It comes from a group of fishes (the pycnodontids) that are famous for their crushing teeth. It is like finding a sheep with a snarl like a wolf. But what was even more remarkable is that it was from the Jurassic. Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time. Sharks have been able to bite out chunks of flesh but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later."

Or, so it had seemed.

"The new finding represents the earliest record of a bony fish that bit bits off other fishes, and what's more it was doing it in the sea," Bellwood says, noting that today's piranhas all live in freshwater. "So when dinosaurs were walking the earth and small dinosaurs were trying to fly with the pterosaurs, fish were swimming around their feet tearing the fins or flesh off each other."

The researchers call the new find a "staggering example of evolutionary versatility and opportunism." With one of the world's best known and studied fossil deposits continuing to throw up such surprises, they intend to keep up the search for even more fascinating finds.

Funding for this project was provided by the Volkswagen Foundation, Deutsche Forschungsgemeinschaft, and the Australian Research Council.





Contacts and sources:     .
Carly Britton
Cell Press

Citation: Current Biology, Kölbl-Ebert et al.: "A Piranha-like Pycnodontiform Fish from the Late Jurassic" https://www.cell.com/current-biology/fulltext/S0960-9822(18)31208-9 



Superflares From Young Red Dwarf Stars Imperil Planets



The word "HAZMAT" describes substances that pose a risk to the environment, or even to life itself. Imagine the term being applied to entire planets, where violent flares from the host star may make worlds uninhabitable by affecting their atmospheres.

NASA's Hubble Space Telescope is observing such stars through a large program called HAZMAT -- Habitable Zones and M dwarf Activity across Time.

"M dwarf" is the astronomical term for a red dwarf star -- the smallest, most abundant and longest-lived type of star in our galaxy. The HAZMAT program is an ultraviolet survey of red dwarfs at three different ages: young, intermediate, and old.

Violent outbursts of seething gas from young red dwarf stars may make conditions uninhabitable on fledgling planets. In this artist's rendering, an active, young red dwarf (right) is stripping the atmosphere from an orbiting planet (left). Scientists found that flares from the youngest red dwarfs they surveyed — approximately 40 million years old — are 100 to 1,000 times more energetic than when the stars are older. They also detected one of the most intense stellar flares ever observed in ultraviolet light — more energetic than the most powerful flare ever recorded from our Sun.
artist's sketch of red dwarf and steaming planet
Credits: NASA, ESA and D. Player (STScI)

Stellar flares from red dwarfs are particularly bright in ultraviolet wavelengths, compared with Sun-like stars. Hubble's ultraviolet sensitivity makes the telescope very valuable for observing these flares. The flares are believed to be powered by intense magnetic fields that get tangled by the roiling motions of the stellar atmosphere. When the tangling gets too intense, the fields break and reconnect, unleashing tremendous amounts of energy.

The team has found that the flares from the youngest red dwarfs they surveyed -- just about 40 million years old -- are 100 to 1,000 times more energetic than when the stars are older. This younger age is when terrestrial planets are forming around their stars.

Approximately three-quarters of the stars in our galaxy are red dwarfs. Most of the galaxy's "habitable-zone" planets -- planets orbiting their stars at a distance where temperatures are moderate enough for liquid water to exist on their surface -- likely orbit red dwarfs. In fact, the nearest star to our Sun, a red dwarf named Proxima Centauri, has an Earth-size planet in its habitable zone.

However, young red dwarfs are active stars, producing ultraviolet flares that blast out so much energy that they could influence atmospheric chemistry and possibly strip off the atmospheres of these fledgling planets.

"The goal of the HAZMAT program is to help understand the habitability of planets around low-mass stars," explained Arizona State University's Evgenya Shkolnik, the program's principal investigator. "These low-mass stars are critically important in understanding planetary atmospheres."

The results of the first part of this Hubble program are being published in The Astrophysical Journal. This study examines the flare frequency of 12 young red dwarfs. "Getting these data on the young stars has been especially important, because the difference in their flare activity is quite large as compared to older stars," said Arizona State University's Parke Loyd, the first author on this paper.

The observing program detected one of the most intense stellar flares ever observed in ultraviolet light. Dubbed the "Hazflare," this event was more energetic than the most powerful flare from our Sun ever recorded.

"With the Sun, we have a hundred years of good observations," Loyd said. "And in that time, we've seen one, maybe two, flares that have an energy approaching that of the Hazflare. In a little less than a day's worth of Hubble observations of these young stars, we caught the Hazflare, which means that we're looking at superflares happening every day or even a few times a day."

Could super-flares of such frequency and intensity bathe young planets in so much ultraviolet radiation that they forever doom chances of habitability? According to Loyd, "Flares like we observed have the capacity to strip away the atmosphere from a planet. But that doesn't necessarily mean doom and gloom for life on the planet. It just might be different life than we imagine. Or there might be other processes that could replenish the atmosphere of the planet. It's certainly a harsh environment, but I would hesitate to say that it is a sterile environment."

The next part of the HAZMAT study will be to study intermediate-aged red dwarfs that are 650 million years old. Then the oldest red dwarfs will be analyzed and compared with the young and intermediate stars to understand the evolution of the ultraviolet radiation environment of low-mass planets around these low-mass stars.


The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.




Contacts and sources:
Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Evgenya Shkolnik  / Parke Loyd
Arizona State University, Tempe, Arizona


Citation:




Scientific Research Will Help to Understand the Origin of Life in the Universe



Scientists from Samara University and several universities in the USA have proposed and experimentally confirmed new fundamental chemical mechanisms for the synthesis of polycyclic aromatic hydrocarbons (PAHs).

Until now, in the scientific community there has been the prevailing view that thermal processes associated exclusively with the combustion and high-temperature processing of organic raw materials such as oil, coal, wood, garbage, food, tobacco underpin the formation of PAHs. However, the scientists from Samara University, together with their colleagues from the University of Hawaii, Florida International University, and Lawrence Berkeley National Laboratory proved that the chemical synthesis of PAHs can occur at very low temperatures, namely -183 C.

The described processes make it possible to understand how complex molecules that are related to the origin of life in the Universe are formed.

Credit: Samara University


Their attention to this topic was attracted, among other things, by the results of the NASA and the European Space Agency mission "Cassini-Huygens" to Saturn's largest moon, Titan. During the space mission of an automatic interplanetary station the benzene molecule was discovered in the atmosphere of Titan. This, in turn, led scientists to believe that the emergence and growth of the orange-brownish haze layers that surround this moon is exactly the responsibility of PAHs. However, the fundamental chemical mechanisms leading to the chemical synthesis of PAHs in the atmosphere of Titan at very low temperatures were not disclosed.

Within the framework of the megagrant "Development of Physically Grounded Combustion Models" under the guidance of Professor of Florida International University Alexander Mebel, the scientists from Samara University searched for the mechanisms of PAH formation using modern high-precision quantum chemical calculation methods. Based on these data, their colleagues from the University of Hawaii and Lawrence Berkeley National Laboratory conducted laboratory experiments that confirmed that prototypes of PAH molecules (anthracene and phenanthrene) are synthesized in barrier-free reactions that take place at low temperatures typical of Titan atmosphere. Anthracene and phenanthrene, in turn, are the original "bricks" for larger PAH molecules, as well as precursors of more complex chemical compounds that were found in the orange-brownish organic haze layers surrounding the moon of Saturn.

"Experimental detection and theoretical description of these elementary chemical reactions change the well-established notion that PAHs can be formed and are able to grow only at very high temperatures, for example, in flames of organic fuels under terrestrial conditions, - concluded Alexander Mebel. - And this means that our discovery leads to the changing of existing scientific views on how PAHs can be formed and grow."

"Traditionally, models of PAH synthesis in hydrocarbon-rich atmospheres of the planets and their moons, such as Titan, assumed the presence of high temperatures, - emphasizes Professor at the University of Hawaii Ralf Kaiser. We provide evidence for a low-temperature reaction pathway".

Understanding the mechanism of PAH growth at low temperatures will allow scientists to understand how complex organic molecules that are related to the origin of life can be formed in the Universe. "Molecules similar to small PAHs, but containing nitrogen atoms, are key components of ribonucleic acids (RNA, DNA) and some amino acids, that is, components of proteins, - notes Alexander Mebel. - Therefore, the growth mechanism of PAHs can be associated with chemical evolution in the Universe, leading to the origin of life".

Moreover, the study of the atmosphere of Titan helps to understand the complex chemical processes occurring not only on the Earth, but also on other moons and planets. "Using new data, scientists can better understand the origin of life on the Earth at the time when nitrogen was more common in its atmosphere, as it is now on Titan", - said Musahid Ahmed, a scientist at Lawrence Berkeley National Laboratory.

As for the application of the presented work it should be mentioned that the understanding the mechanism of PAH growth in flames will allow the scientists of Samara University to offer engineers the mechanisms to reduce the release of these carcinogenic substances in the exhaust of various types of engines. And this is one of the main goals of the megagrant implemented by the University.

Polycyclic aromatic hydrocarbons are organic compounds which chemical structure contains two or more condensed benzene rings. In nature, PAHs are formed in the process of cellulose pyrolysis and are found in coal, brown coal and anthracite formations, and also as a product of incomplete combustion during forest fires. Many PAHs are potent carcinogens. The main sources of the emission of technogenic PAHs into the environment are enterprises of the energy complex, automobile transport, chemical and petroleum refining industry.

Megagrant "Development of Physically Grounded Combustion Models" has been implemented within the Russian Federation governmental support for scientific research since 2016. International scientific laboratory "Physics and Chemistry of Combustion" under the guidance of Professor of Florida International University Alexander Mebel was established to implement the megagrant in the University. The project is aimed at solving the burning problem -- prevention of environmental pollution. The results of research conducted by the scientists of Samara University in close cooperation with both international and Russian research centres will contribute to the creation of more environmentally friendly and efficient combustion chambers for gas turbine engines.


Contacts and sources:
Olga BuhnerSamara University




Citation:
Low-temperature formation of polycyclic aromatic hydrocarbons in Titan’s atmosphere
Long Zhao,  Ralf I. Kaiser,  Bo Xu,  Utuq Ablikim,  Musahid Ahmed,  Mikhail M. Evseev,  Eugene K. Bashkirov,  Valeriy N. Azyazov &  Alexander M. Mebel
Nature Astronomy (2018) http://dx.doi.org/10.1038/s41550-018-0585-y




Titanic Structure in the Early Universe Discovered



An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive structure yet found at such a remote time and distance.

The team that made the discovery was led by Olga Cucciati of Istituto Nazionale di Astrofisica (INAF) Bologna, Italy and project scientist Brian Lemaux in the Department of Physics, College of Letters and Science at the University of California, Davis, and included Lori Lubin, professor of physics at UC Davis. They used the VIMOSinstrument on ESO's Very Large Telescope in Paranal, Chile to identify a gigantic proto-supercluster of galaxies forming in the early Universe, just 2.3 billion years after the Big Bang.

Hyperion is the largest and most massive structure to be found so early in the formation of the Universe, with a calculated mass more than one million billion times that of the Sun. This enormous mass is similar to that of the largest structures observed in the Universe today, but finding such a massive object in the early Universe surprised astronomers.

An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive structure yet found at such a remote time and distance. It has a mass estimated at a million billion Suns.

Credit: Luis Calçada & Olga Cucciati/ESO


"This is the first time that such a large structure has been identified at such a high redshift, just over 2 billion years after the Big Bang," Cucciati said. "Normally these kinds of structures are known at lower redshifts, which means when the Universe has had much more time to evolve and construct such huge things. It was a surprise to see something this evolved when the Universe was relatively young."

Supercluster mapped in three dimensions

Located in the constellation of Sextans (The Sextant), Hyperion was identified by a novel technique developed at UC Davis to analyze the vast amount of data obtained from the VIMOS Ultra-Deep Survey led by Olivier Le Fèvre from Laboratoire d'Astrophysique de Marseille, Centre National de la Recherche Scientifique and Centre National d'Etudes Spatiales. The VIMOS instrument can measure the distance to hundreds of galaxies at the same time, making it possible to map the position of galaxies within the forming supercluster in three dimensions.

The team found that Hyperion has a very complex structure, containing at least seven high-density regions connected by filaments of galaxies, and its size is comparable to superclusters closer to Earth, though it has a very different structure.

"Superclusters closer to Earth tend to a much more concentrated distribution of mass with clear structural features," Lemaux said. "But in Hyperion, the mass is distributed much more uniformly in a series of connected blobs, populated by loose associations of galaxies."

The researchers are comparing the Hyperion findings with results from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey, led by Lubin. The ORELSE survey uses telescopes at the W.M. Keck Observatory in Hawaii to study superclusters closer to Earth. Lubin and Lemaux are also using the Keck observatory to map out Hyperion and similar structures more completely.

The contrast between Hyperion and less distant superclusters is most likely due to the fact that nearby superclusters have had billions of years for gravity to gather matter together into denser regions -- a process that has been acting for far less time in the much younger Hyperion.

Given its size so early in the history of the Universe, Hyperion is expected to evolve into something similar to the immense structures in the local Universe such as the superclusters making up the Sloan Great Wall or the Virgo Supercluster that contains our own galaxy, the Milky Way.

"Understanding Hyperion and how it compares to similar recent structures can give insights into how the Universe developed in the past and will evolve into the future, and allows us the opportunity to challenge some models of supercluster formation," Cucciati said. "Unearthing this cosmic titan helps uncover the history of these large-scale structures."

This research will be published in an upcoming issue of the journal Astronomy & Astrophysics.


Contacts and sources:
Andy FellUniversity of California, Davis





New Study Sets a Size Limit for Undiscovered Subatomic Particles

A new study suggests that many theorized heavy particles, if they exist at all, do not have the properties needed to explain the predominance of matter over antimatter in the universe.

If confirmed, the findings would force significant revisions to several prominent theories posed as alternatives to the Standard Model of particle physics, which was developed in the early 1970s. Researchers from Yale, Harvard, and Northwestern University conducted the study, which was published Oct. 17 in the journal Nature.

The discovery is a window into the mind-bending nature of particles, energy, and forces at infinitesimal scales, specifically in the quantum realm, where even a perfect vacuum is not truly empty. Whether that emptiness is located between stars or between molecules, numerous experiments have shown that any vacuum is filled with every type of subatomic particle -- and their antimatter counterparts -- constantly popping in and out of existence.

In this artist's representation, an electron travels between two lasers in an experiment. The electron is spinning about its axis as a cloud of other subatomic particles are constantly emitted and reabsorbed. Some theories in particle physics predict particles, as yet undetected, that would cause the cloud to appear very slightly pear shaped when seen from a distance. With the support of the National Science Foundation, ACME researchers created an experiment setup look at that shape with extreme precision. To the limits of their experiment, they saw a perfectly round sphere, implying that certain types of new particles, if they exist at all, have properties different from those theorists expected.
Credit: Nicolle R. Fuller, NSF


One approach to identifying them is to take a closer look at the shape of electrons, which are surrounded by subatomic particles. Researchers examine tiny distortions in the vacuum around electrons as a way to characterize the particles.

The new study reports work done with the Advanced Cold Molecule Electron Dipole Moment (ACME) experiment, a collaborative effort to detect the electric dipole moment (EDM) of the electron. An electron EDM corresponds to a small bulge on one end of the electron, and a dent on the opposite end.

The Standard Model predicts an extremely small electron EDM, but there are a number of cosmological questions -- such as the preponderance of matter over antimatter in the aftermath of the Big Bang -- that have pointed scientists in the direction of heavier particles, outside the parameters of the Standard Model, that would be associated with a much larger electron EDM. "The Standard Model makes predictions that differ radically from its alternatives and ACME can distinguish those," said David DeMille, who leads the ACME group at Yale. "Our result tells the scientific community that we need to seriously rethink those alternative theories."

Indeed, the Standard Model predicts that particles surrounding an electron will squash its charge ever so slightly, but this effect would only be noticeable at a resolution 1 billion times more precise than ACME observed. However, in models predicting new types of particles -- such as supersymmetry and grand unified theories -- a deformation in the shape at ACME's level of precision was broadly expected.

"An electron always carries with it a cloud of fleeting particles, distortions in the vacuum around it," said John Gillaspy, program director for atomic, molecular, and optical physics for the National Science Foundation (NSF), which has funded the ACME research for nearly a decade. "The distortions cannot be separated from the particle itself, and their interactions lead to the ultimate shape of the electron's charge."

ACME uses a unique process that involves firing a beam of cold thorium-oxide (ThO) molecules -- a million of them per pulse, 50 times per second -- into a chamber the size of a large desk.

Within that chamber, lasers orient the molecules and the electrons within, as they soar between two charged glass plates inside a carefully controlled magnetic field. ACME researchers watch for the light the molecules emit when targeted by a carefully tuned set of readout lasers. The light provides information to determine the shape of the electron's charge.

By controlling some three dozen parameters, from the tuning of the lasers to the timing of experimental steps, ACME achieved a 10-fold detection improvement over the previous record holder: ACME's 2014 experiment. The ACME researchers said they expect to reach another 10-fold improvement on precision in future versions of the experiment.


Contacts and sources:
Jim Shelton
Yale University


Wednesday, October 17, 2018

Scientists ID Three Causes of Earth's Spin Axis Drift



A typical desk globe is designed to be a geometric sphere and to rotate smoothly when you spin it. Our actual planet is far less perfect -- in both shape and in rotation.

Earth is not a perfect sphere. When it rotates on its spin axis -- an imaginary line that passes through the North and South Poles -- it drifts and wobbles. These spin-axis movements are scientifically referred to as "polar motion." Measurements for the 20th century show that the spin axis drifted about 4 inches (10 centimeters) per year. Over the course of a century, that becomes more than 11 yards (10 meters).

The observed direction of polar motion, shown as a light blue line, compared with the sum (pink line) of the influence of Greenland ice loss (blue), postglacial rebound (yellow) and deep mantle convection (red). The contribution of mantle convection is highly uncertain. 
The observed direction of polar motion
Credit: NASA/ JPL-Caltech

Using observational and model-based data spanning the entire 20th century, NASA scientists have for the first time identified three broadly-categorized processes responsible for this drift -- contemporary mass loss primarily in Greenland, glacial rebound, and mantle convection.

"The traditional explanation is that one process, glacial rebound, is responsible for this motion of Earth's spin axis. But recently, many researchers have speculated that other processes could have potentially large effects on it as well," said first author Surendra Adhikari of NASA's Jet Propulsion Laboratory in Pasadena, California. "We assembled models for a suite of processes that are thought to be important for driving the motion of the spin axis. We identified not one but three sets of processes that are crucial -- and melting of the global cryosphere (especially Greenland) over the course of the 20th century is one of them."

In general, the redistribution of mass on and within Earth -- like changes to land, ice sheets, oceans and mantle flow -- affects the planet's rotation. As temperatures increased throughout the 20th century, Greenland's ice mass decreased. In fact, a total of about 7,500 gigatons -- the weight of more than 20 million Empire State Buildings -- of Greenland's ice melted into the ocean during this time period. This makes Greenland one of the top contributors of mass being transferred to the oceans, causing sea level to rise and, consequently, a drift in Earth's spin axis.

While ice melt is occurring in other places (like Antarctica), Greenland's location makes it a more significant contributor to polar motion.

"There is a geometrical effect that if you have a mass that is 45 degrees from the North Pole -- which Greenland is -- or from the South Pole (like Patagonian glaciers), it will have a bigger impact on shifting Earth's spin axis than a mass that is right near the Pole," said coauthor Eric Ivins, also of JPL.

Previous studies identified glacial rebound as the key contributor to long-term polar motion. And what is glacial rebound? During the last ice age, heavy glaciers depressed Earth's surface much like a mattress depresses when you sit on it. As that ice melts, or is removed, the land slowly rises back to its original position. In the new study, which relied heavily on a statistical analysis of such rebound, scientists figured out that glacial rebound is likely to be responsible for only about a third of the polar drift in the 20th century.

The authors argue that mantle convection makes up the final third. Mantle convection is responsible for the movement of tectonic plates on Earth's surface. It is basically the circulation of material in the mantle caused by heat from Earth's core. Ivins describes it as similar to a pot of soup placed on the stove. As the pot, or mantle, heats, the pieces of the soup begin to rise and fall, essentially forming a vertical circulation pattern -- just like the rocks moving through Earth's mantle.

With these three broad contributors identified, scientists can distinguish mass changes and polar motion caused by long-term Earth processes over which we have little control from those caused by climate change. They now know that if Greenland's ice loss accelerates, polar motion likely will, too.

The paper in Earth and Planetary Science Letters is titled "What drives 20th century polar motion?" Besides JPL, coauthor institutions include the German Research Centre for Geosciences, Potsdam; the University of Oslo, Norway; Technical University of Denmark, Kongens Lyngby; the Geological Survey of Denmark and Greenland, Copenhagen, Denmark; and the University of Bremen, Germany. An interactive simulation of how multiple processes contribute to the wobbles in Earth's spin axis is available at:


Contacts and sources:
Esprit Smith
Jet Propulsion Laboratory





Mystery Like a Wrench in Earth's Engine

Researchers at CU Boulder report that they may have solved a geophysical mystery, pinning down the likely cause of a phenomenon that resembles a wrench in the engine of the planet.

In a study published today in Nature Geoscience, the team explored the physics of “stagnant slabs.” These geophysical oddities form when huge chunks of Earth’s oceanic plates are forced deep underground at the edges of certain continental plates. The chunks sink down into the planet’s interior for hundreds of miles until they suddenly—and for reasons scientists can’t explain—stop like a stalled car.

Earth's mantle (dark red) lies below the crust (brown layer near the surface) and above the outer core (bright red). 
Graphic of Earth's interior
Credit: CC image by Argonne National Laboratory via Flickr

CU Boulder’s Wei Mao and Shijie Zhong, however, may have found the reason for that halt. Using computer simulations, the researchers examined a series of stagnant slabs in the Pacific Ocean near Japan and the Philippines. They discovered that these cold rocks seem to be sliding on a thin layer of weak material lying at the boundary of the planet’s upper and lower mantle—roughly 660 kilometers, or 410 miles, below the surface.

And the stoppage is likely temporary: “Although we see these slabs stagnate, they are a fairly recent phenomena, probably happening in the last 20 million years,” said Zhong, a co-author of the new study and a professor in CU Boulder’s Department of Physics.
Going stagnant

Graphic of stagnant slabs under the Japanese island of Honshu (top) and the Mariana Trench (bottom) using seismic data (left) and computer simulations (right). Stagnant slabs (blue) plunge down to the border between the upper and lower mantle then screech to a stop.


Credit: Mao & Zhong 2018, Nature Geoscience

The findings matter for tectonics and volcanism on the Earth’s surface. Zhong explained that the planet’s mantle, which lies above the core, generates vast amounts of heat. To cool the globe down, hotter rocks rise up through the mantle and colder rocks sink.

“You can think of this mantle convection as a big engine that drives all of what we see on Earth’s surface: earthquakes, mountain building, plate tectonics, volcanos and even Earth’s magnetic field,” Zhong said.

The existence of stagnant slabs, which geophysicists first located about a decade ago, however, complicates that metaphor, suggesting that Earth’s engine may grind to a halt in some areas. That, in turn, may change how scientists think diverse features, such as East Asia’s roiling volcanos, form over geologic time.

Scientists have mostly located such slabs in the western Pacific Ocean, specifically off the east coast of Japan and deep below the Mariana Trench. They occur at the sites of subduction zones, or areas where oceanic plates at the surface of the planet plunge hundreds of miles below ground.

Slabs seen at similar sites near North and South America behave in ways that geophysicists might expect: They dive through Earth’s upper mantle and into the lower mantle where they heat up near the core.

But around Asia, “they simply don’t go down,” Zhong said. Instead, the slabs spread out horizontally near the boundary between the upper and lower mantle, a point at which heat and pressure inside Earth cause minerals to change from one phase to another.
Slab sliding

To find out why slabs go stagnant, Zhong and Mao, a graduate student in physics, developed realistic simulations of how energy and rock cycle around the entire planet.

They found that the only way they could explain the behavior of the stagnant slabs was if a thin layer of less-viscous rock was wedged in between the two halves of the mantle. While no one has directly observed such a layer, researchers have predicted that it exists by studying the effects of heat and pressure on rock.

If it does, such a layer would act like a greasy puddle in the middle of the planet. “If you introduce a weak layer at that depth, somehow the reduced viscosity helps lubricate the region,” Zhong said. “The slabs get deflected and can keep going for a long distance horizontally.”

Stagnant slabs seem to occur off the coast of Asia, but not the Americas, because the movement of the continents above gives those chunks of rock more room to slide. Zhong, however, said that he doesn’t think the slabs will stay stuck. With enough time, he suspects that they will break through the slick part of the mantle and continue their plunge toward the planet’s core.

The planet, in other words, would still behave like an engine—just with a few sticky spots. “New research suggests that the story may be more complicated than we previously thought,” Zhong said.



Contacts and sources:
Daniel Strain
University of Colorado at Boulder

Citation: Slab stagnation due to a reduced viscosity layer beneath the mantle transition zone
Wei Mao, Shijie Zhong.. Nature Geoscience, 2018; DOI: 10.1038/s41561-018-0225-2

How Earth Builds Supereruption-Feeding Magma Systems



To figure out where magma gathers in the earth’s crust and for how long, Vanderbilt University volcanologist Guilherme Gualda and his students traveled to its most active cluster, the Taupo Volcanic Zone of New Zealand, where some of the biggest eruptions of the last 2 million years occurred — seven in a period between 350,000 and 240,000 years ago.

circles representing the volume of magma erupted from different volcanoes
Credit: USGS

After studying layers of pumice visible in road cuts and other outcrops, measuring the amount of crystals in the samples and using thermodynamic models, they determined that magma moved closer to the surface with each successive eruption.


The project fits into Gualda’s ongoing work studying supereruptions – how the magma systems that feed them are built and how the Earth reacts to repeated input of magma over short periods of time.

“As the system resets, the deposits become shallower,” said Gualda, associate professor of earth and environmental sciences. “The crust is getting warmer and weaker, so magma can lodge itself at shallower levels.”

What’s more, the dynamic nature of the Taupo Volcanic Zone’s crust made it more likely for the magma to erupt than be stored in the crust. The more frequent, smaller eruptions, which each produced 50 to 150 cubic kilometers of magma, likely prevented a supereruption. Supereruptions produce more than 450 cubic kilometers of magma and they affect the earth’s climate for years following the eruption.

“You have magma sitting there that’s crystal-poor, melt-rich for few decades, maybe 100 years, and then it erupts,” Gualda said. “Then another magma body is established, but we don’t know how gradually that body assembles. It’s a period in which you’re increasing the amount of melt in the crust.”

The question that remains is how long it took for these crystal-rich magma bodies to assemble between eruptions. It could be thousands of years, Gualda said, but he believes it’s shorter than that.

His findings are in a paper titled “Climbing the crustal ladder: Magma storage-depth evolution during a volcanic flare-up,” which appears today in the journal Science Advances.

This work was made possible through National Science Foundation grant EAR-1151337.



Contacts and sources:
 Heidi Hall
Vanderbilt University

Citation: Climbing the crustal ladder: Magma storage-depth evolution during a volcanic flare-up.
Guilherme A. R. Gualda, Darren M. Gravley, Michelle Connor, Brooke Hollmann, Ayla S. Pamukcu, Florence Bégué, Mark S. Ghiorso, Chad D. Deering. Science Advances, 2018; 4 (10): eaap7567 DOI: 10.1126/sciadv.aap7567




The Bees Went Quiet During the Total Eclipse of 2017



A study conducted during the 2017 total solar eclipse in North America found that bees remained active during the partial-eclipse phases both before and after the period of totality, but they essentially ceased flying during totality. Their flights also tended to be longer in duration immediately before and after totality, an indication that bees may have slowed down their flight speed or returned to their nests as light dimmed. Results of the study are published in the Annals of the Entomological Society of America
Bombus sp bumble bee
Photo credit: Susan Ellis, Bugwood.org

While millions of Americans took a break from their daily routines on August 21, 2017, to witness a total solar eclipse, they might not have noticed a similar phenomenon happening nearby: In the path of totality, bees took a break from their daily routines, too.

In an unprecedented study of a solar eclipse’s influence on bee behavior, researchers at the University of Missouri organized a cadre of citizen scientists and elementary school classrooms in setting up acoustic monitoring stations to listen in on bees’ buzzing—or lack thereof—as the 2017 eclipse passed over. The results, published in the Annals of the Entomological Society of America, were clear and consistent at locations across the country: Bees stopped flying during the period of total solar eclipse.

“We anticipated, based on the smattering of reports in the literature, that bee activity would drop as light dimmed during the eclipse and would reach a minimum at totality,” says Candace Galen, Ph.D., professor of biological sciences at the University of Missouri and lead researcher on the study. “But, we had not expected that the change would be so abrupt, that bees would continue flying up until totality and only then stop, completely. It was like ‘lights out’ at summer camp! That surprised us.”

As anticipation mounted for the eclipse, “it seemed as if everyone and their dog was asking me what animals would do during a total eclipse,” Galen says. However, few formal studies had ever examined the behavior of insects, specifically, during a solar eclipse, and none had looked at bees. Galen and colleagues, meanwhile, had recently field-tested a system to track bee pollination remotely by listening for their flight buzzes in soundscape recordings.

“It seemed like the perfect fit,” Galen says. “The tiny microphones and temperature sensors could be placed near flowers hours before the eclipse, leaving us free to put on our fancy glasses and enjoy the show.”

To study the influence of a total solar eclipse on bee behavior, researchers researchers at the University of Missouri organized a cadre of citizen scientists and elementary school classrooms in setting up acoustic monitoring stations to listen in on bees’ buzzing–or lack thereof–as the August 2017 solar eclipse passed over North America. Here, what looks like a white ball of fur is actually a flash-drive-sized microphone with a windscreen, tied to a short post in a patch of clover.

(Photo credit: Candace Galen, Ph.D)

Supported by a grant from the American Astronomical Society, the project engaged more than 400 participants—including scientists, members of the public, and elementary school teachers and students—in setting up 16 monitoring stations in the path of totality in Oregon, Idaho, and Missouri. At each location, small USB microphones were hung on lanyards near bee-pollinated flowers in areas away from foot and vehicle traffic. In some of the locations, light and temperature data were also captured. Participants then sent the devices to Galen’s lab, where the recordings were matched up with the eclipse periods from each location and analyzed for the number and duration of bee flight buzzes. The recordings didn’t allow for differentiation between bee species, but participant observations indicated most bees monitored were bumble bees (genus Bombus) or honey bees (Apis mellifera).

The data showed that bees remained active during the partial-eclipse phases both before and after totality, but they essentially ceased flying during the period of totality. (Just one buzz was recorded during totality in all of the 16 monitoring locations.) However, shortly before and shortly after totality, bee flights tended to be longer in duration than at times early in the pre-totality phase and late in post-totality. Galen and colleagues interpret these longer flight durations as an indicator of slower flight under reduced light or possibly as the bees returning to their nests.

After elementary-school students participated in a study of bee behavior during the 2017 total solar eclipse, researchers leading the project asked the students to illustrate the eclipse from the bees’ perspective “as a way to synthesize their results.” Illustrations such as that of Olivery Ni, then a fifth-grader at Ulysses S. Grant Elementary School in Columbia, Missouri, “show growth in [students’] understanding of animal behavior over the project—many drawings captured the connections between environmental stimuli, bee sensory systems, and flight responses,” the researchers note.

(Image originally published in Galen et al 2018, Annals of the Entomological Society of America)

Bees commonly fly more slowly at dusk and return to their colonies at night, and so the same behavior triggered by a solar eclipse offers evidence about how they respond to environmental cues when those cues occur unexpectedly.

“The eclipse gave us an opportunity to ask whether the novel environmental context—mid-day, open skies—would alter the bees’ behavioral response to dim light and darkness. As we found, complete darkness elicits the same behavior in bees, regardless of timing or context. And that’s new information about bee cognition,” Galen says.

The researchers also noted the success of the project in engaging students in scientific inquiry and practice. At elementary school classrooms in Columbia, Missouri, for instance, Galen and colleagues report that “young students were asked to predict how bees would respond to the eclipse. Students made predictions based on their life experience, proposing that bees would cease flying at totality because they do not fly at night. After the eclipse, sound clips were shared with students who learned how to measure the frequency, amplitude, and duration of buzzes, and how to use these properties to recognize and count bee buzzes in recordings made at their schools. Fourth and fifth grade students produced buzz counts that matched our research team’s numbers with a correspondence rate of 91 percent.”

Another total solar eclipse for North America is not far away: April 8, 2024. Galen says her team is working to enhance its audio-analysis software to distinguish the flights that foraging bees make when they leave or return to their colonies. Thus prepared, she hopes to answer the question of whether bees return home when the “lights go out” at totality in 2024.

It likely won’t be difficult to find willing citizen scientists and students to help out again.

“The total solar eclipse was a complete crowd-pleaser, and it was great fun to hitch bee research to its tidal wave of enthusiasm,” Galen says.
 


Contacts and sources:
 Entomological Society of America


Citation: “Pollination on the Dark Side: Acoustic Monitoring Reveals Impacts of a Total Solar Eclipse on Flight Behavior and Activity Schedule of Foraging Bees
Annals of the Entomological Society of America



Suspicion and Innuendo in News Coverage Can Fuel Conspiracy Theories

Innuendo and hinting at fake information in news coverage is enough to fuel belief in conspiracy theories, new research shows.

Implication alone can significantly increase belief in false facts, according to a new study.

Experts have said the results show news outlets should be quicker to correct inaccurate information published or broadcast, and be more cautious about who they invite to provide analysis.

Infographic How to spot fake news published by the International Federation of Library Associations and Institutions.png
By IFLA (http://www.ifla.org/publications/node/11174) [CC BY 4.0 (https://creativecommons.org/licenses/by/4.0)], via Wikimedia Commons


University of Exeter academics Benjamin Lyons, Vittorio Merola and Jason Reifler conducted the study with around 1,000 participants last month. The findings were presented at the AAAS conference in Texas.

Professor Reifler said: “This study shows it is easy to spread conspiracy theories. Debunking appears to work—but only up to a point. As a result, media companies need to be cautious about the guests they invite on air or feature in their publications. When guests imply a conspiracy, journalists should push back to the extent they can. Having lived in both the US and the UK, my experience is that UK journalists do a better job at this than their US counterparts. But, there is always room for improvement.”

Participants were asked to read a mock newspaper article. They were divided into five groups: one received information which explicitly promoted a conspiracy theory, another was given the same information together with the facts which debunked this myth. Another group was given information which implicitly hinted at a conspiracy theory, and another had the same facts which debunked it. There was also a control group. All respondents received debunking information at the conclusion of the study.

The participants in the group with “explicit conditions” read an article with explicitly false information – the Zika epidemic in Brazil was caused by the release of genetically modified mosquitoes by a subsidiary of a pharmaceutical company that was hoping to profit from a future vaccine. In reality, genetically modified mosquitoes were released afterthe outbreak as a way to control the spread of Zika, and the company involved does not stand to gain from selling Zika-related pharmaceutical products. The article attributed this false information to “concerned citizens” and said the motive was profit from the vaccines developed by pharmaceutical parent company.

The implicit information given included a quote from a Brazilian politician rhetorically asking “who benefits?” from the sale of the pharmaceutical products.

Professor Reifler said: “The results of the study are intriguing—both explicit and implicit information without debunking increases conspiracy beliefs, compared to the control conditions. While explicit information leads to a greater increase in conspiracy beliefs, implying a conspiracy also leads to an increase, albeit a smaller increase. Fortunately, the debunking information brings conspiracy levels back to the same level as the control. Unfortunately, the debunking information does not reduce conspiracy beliefs below the level found among participants in our control group.”

The research was funded by the European Research Council as part of the Horizon 2020 funding scheme.



Contacts and sources: 
University of Exeter

Citation: Not Just Asking Questions: Effects of Implicit and Explicit Conspiracy Information About Vaccines and Genetic Modification
Benjamin Lyons, Vittorio Merola, Jason Reifler.. Health Communication, 2018; 1 DOI: 10.1080/10410236.2018.1530526



Simple Stickers May Save Lives of Heart Patients and Lower Medical Costs for Families



Heart surgery can be traumatic for patients. Having to continuously monitor your status without a doctor when you are back home can be even scarier. Imagine being able to do that with a simple sticker applied to your body.

Purdue University researchers have advanced a sticker solution moving it several steps closer to reality. The research was recently published in ACS Advanced Materials and Interfaces. A YouTube video is available at http://bit.ly/EPED-Purdue.

“For the first time, we have created wearable electronic devices that someone can easily attach to their skin and are made out of paper to lower the cost of personalized medicine,” said Ramses Martinez, a Purdue assistant professor of industrial engineering and biomedical engineering, who led the research team.

Purdue University researchers have created wearable electronic devices that someone can easily attach to their skin. The devices are made out of paper to lower the cost of personalized medicine.
Credit: Purdue University

Their technology aligns with Purdue's Giant Leaps celebration, acknowledging the university’s global advancements made in health as part of Purdue’s 150th anniversary. This is one of the four themes of the yearlong celebration’s Ideas Festival, designed to showcase Purdue as an intellectual center solving real-world issues.

The “smart stickers” are made of cellulose, which is both biocompatible and breathable. They can be used to monitor physical activity and alert a wearer about possible health risks in real time.

Health professionals could use the Purdue stickers as implantable sensors to monitor the sleep of patients because they conform to internal organs without causing any adverse reactions. Athletes could also use the technology to monitor their health while exercising and swimming.



These stickers are patterned in serpentine shapes to make the devices as thin and stretchable as skin, making them imperceptible for the wearer.

Since paper degrades fast when it gets wet and human skin is prone to be covered in sweat, these stickers were coated with molecules that repel water, oil, dust and bacteria. Each sticker costs about a nickel to produce and can be made using printing and manufacturing technologies similar to those used to print books at high speed.

“The low cost of these wearable devices and their compatibility with large-scale manufacturing techniques will enable the quick adoption of these new fully disposable, wearable sensors in a variety of health care applications requiring single-use diagnostic systems,” Martinez said.

The technology is patented through the Purdue Office of Technology Commercialization. They are continuing to look for partners to test and commercialize their technology.

The Purdue Office of Technology Commercialization operates one of the most comprehensive technology transfer programs among leading research universities in the U.S. Services provided by this office support the economic development initiatives of Purdue University and benefit the university's academic activities. The office is managed by the Purdue Research Foundation, which received the 2016 Innovation and Economic Prosperity Universities Award for Innovation from the Association of Public and Land-grant Universities.


Contacts and sources:
Writer: Chris Adam
Source: Ramses Martinez
Purdue University


Citation: Wearable and Implantable Epidermal Paper-Based Electronics.
Behnam Sadri, Debkalpa Goswami, Marina Sala de Medeiros, Aniket Pal, Beatriz Castro, Shihuan Kuang, Ramses V. Martinez. ACS Applied Materials & Interfaces, 2018; 10 (37): 31061 DOI: 10.1021/acsami.8b11020



Giant Planets Around Young Star Raise Questions About How Planets Form

Researchers have identified a young star with four Jupiter and Saturn-sized planets in orbit around it, the first time that so many massive planets have been detected in such a young system. The system has also set a new record for the most extreme range of orbits yet observed: the outermost planet is more than a thousand times further from the star than the innermost one, which raises interesting questions about how such a system might have formed.

The star is just two million years old - a 'toddler' in astronomical terms - and is surrounded by a huge disc of dust and ice. This disc, known as a protoplanetary disc, is where the planets, moons, asteroids and other astronomical objects in stellar systems form.

The star was already known to be remarkable because it contains the first so-called hot Jupiter - a massive planet orbiting very close to its parent star - to have been discovered around such a young star. Although hot Jupiters were the first type of exoplanet to be discovered, their existence has long puzzled astronomers because they are often thought to be too close to their parent stars to have formed in situ.

This is an artist's impression of four gas giant in orbit around CI Tau.

Credit: University of Cambridge

Now, a team of researchers led by the University of Cambridge have used the Atacama Large Millimeter/submillimeter Array (ALMA) to search for planetary 'siblings' to this infant hot Jupiter. Their image revealed three distinct gaps in the disc, which, according to their theoretical modelling, were most likely caused by three additional gas giant planets also orbiting the young star. Their results are reported in The Astrophysical Journal Letters.

The star, CI Tau, is located about 500 light years away in a highly-productive stellar 'nursery' region of the galaxy. Its four planets differ greatly in their orbits: the closest (the hot Jupiter) is within the equivalent of the orbit of Mercury, while the farthest orbits at a distance more than three times greater than that of Neptune. The two outer planets are about the mass of Saturn, while the two inner planets are respectively around one and 10 times the mass of Jupiter.

The discovery raises many questions for astronomers. Around 1% of stars host hot Jupiters, but most of the known hot Jupiters are hundreds of times older than CI Tau. "It is currently impossible to say whether the extreme planetary architecture seen in CI Tau is common in hot Jupiter systems because the way that these sibling planets were detected - through their effect on the protoplanetary disc - would not work in older systems which no longer have a protoplanetary disc," said Professor Cathie Clarke from Cambridge's Institute of Astronomy, the study's first author.

According to the researchers, it is also unclear whether the sibling planets played a role in driving the innermost planet into its ultra-close orbit, and whether this is a mechanism that works in making hot Jupiters in general. And a further mystery is how the outer two planets formed at all.

"Planet formation models tend to focus on being able to make the types of planets that have been observed already, so new discoveries don't necessarily fit the models," said Clarke. "Saturn mass planets are supposed to form by first accumulating a solid core and then pulling in a layer of gas on top, but these processes are supposed to be very slow at large distances from the star. Most models will struggle to make planets of this mass at this distance."

The task ahead will be to study this puzzling system at multiple wavelengths to get more clues about the properties of the disc and its planets. In the meantime, ALMA - the first telescope with the capability of imaging planets in the making - will likely throw out further surprises in other systems, re-shaping our picture of how planetary systems form.

The research has been supported by the European Research Council.


Contacts and sources:
Sarah CollinsUniversity of Cambridge


Citation: High-resolution Millimeter Imaging of the CI Tau Protoplanetary Disk: A Massive Ensemble of Protoplanets from 0.1 to 100 au The Astrophysical Journal Letters, Volume 866, Number 1 http://dx.doi.org/10.3847/2041-8213/aae36b