Tuesday, June 19, 2018

Two Strange New Creatures Discovered from Dawn of Animal Life

Earth’s first complex animals were an eclectic bunch that lived in the shallow oceans between 580-540 million years ago.

The iconic Dickinsonia — large flat animals with a quilt-like appearance — were joined by tube-shaped organisms, frond-like creatures that looked more like plants, and several dozen other varieties already characterized by scientists.

Add to that list two new animals discovered by a University of California Riverside (UCR)-led team of researchers:
  • Obamus coronatus, a name that honors President Barack Obama’s passion for science. This disc-shaped creature was between 0.5-2 cm across with raised spiral grooves on its surface. Obamus coronatus did not seem to move around, rather it was embedded to the ocean mat, a thick layer of organic matter that covered the early ocean floor.
  • Attenborites janeae, named after the English naturalist and broadcaster Sir David Attenborough for his science advocacy and support of paleontology. This tiny ovoid, less than a centimeter across, was adorned with internal grooves and ridges giving it a raisin-like appearance.

Two new Ediacaran-era fossils discovered by UCR researchers: Obamus coronatus (left) and Attenborites janeae.
Photos of the two new fossils discovered by UCR researchers.
 Credit:  UCR

The discovery of Obamus coronatus was published online June 14 in the Australian Journal of Earth Sciences, or AJES, and the Attenborites janeae paper is forthcoming in the same journal. The studies were led by Mary Droser, a professor of paleontology in UCR’s Department of Earth Sciences. Both papers will be included in print in a 2019 thematic AJES issue focusing on South Australia’s Flinders Ranges region, where the discoveries were made.

Part of the Ediacara Biota, the soft-bodied animals are visible as fossils cast in fine-grained sandstone that have been preserved for hundreds of millions of years. These Precambrian lifeforms represent the dawn of animal life and are named after the Ediacara Hills in the Flinders Ranges, the first of several areas in the world where they have been found.

An extremely well-preserved example of the fossil animal Dickinsonia costata found in a bed that was recently excavated by UCR researchers.

Credit: UCR


In the hierarchical taxonomic classification system, the Ediacara Biota are not yet organized into families, and little is known about how they relate to modern animals. About 50 genera have been described, which often have only one species.

“The two genera that we identified are a new body plan, unlike anything else that has been described,” Droser said. “We have been seeing evidence for these animals for quite a long time, but it took us a while to verify that they are animals within their own rights and not part of another animal.”

The animals were glimpsed in a particularly well-preserved fossil bed described in another paper published by Droser’s group that will be included in the Flinders Ranges issue of AJES. The researchers dubbed this fossil bed “Alice’s Restaurant Bed,” a tribute to the Arlo Guthrie song and its lyric, “You can get anything you want at Alice’s Restaurant.”

“I’ve been working in this region for 30 years, and I’ve never seen such a beautifully preserved bed with so many high quality and rare specimens, including Obamus and Attenborites,” Droser said. “The AJES issue on the Flinders Ranges will support South Australia’s effort to obtain World Heritage Site status for this area, and this new bed demonstrates the importance of protecting it.”

The titles of the papers are:

Stuck in the mat: Obamus coronatus, a new benthic organism from the Ediacara Member, Rawnsley Quartzite, South Australia

You can get anything you want from Alice’s Restaurant Bed: exceptional preservation and an unusual fossil assemblage from a newly excavated bed (Ediacara Member, Nilpena, South Australia)

Attenborites janeae: A new enigmatic organism from the Ediacara Member (Rawnsley Quartzite), South Australia (forthcoming).

In addition to Droser, authors from UCR include Scott Evans, a graduate student in the Department of Earth Sciences; and Peter Dzaugis, a volunteer and field assistant. The work was performed in collaboration with James Gehling of the South Australian Museum in Adelaide, a co-author on the papers.

Ian Hughes of Scripps Institute of Oceanography at UC San Diego, and Emily Hughes of Wesleyan University also participated in the research.



Contacts and sources:
Sarah Nightingale
University of California Riverside

Citation: Stuck in the mat: Obamus coronatus, a new benthic organism from the Ediacara Member, Rawnsley Quartzite, South Australia

You can get anything you want from Alice’s Restaurant Bed: exceptional preservation and an unusual fossil assemblage from a newly excavated bed (Ediacara Member, Nilpena, South Australia)

Monday, June 18, 2018

Explosive Volcanoes Spawned Mysterious Martian Rock Formation

Explosive volcanic eruptions that shot jets of hot ash, rock and gas skyward are the likely source of a mysterious Martian rock formation, a new study finds. The new finding could add to scientists' understanding of Mars's interior and its past potential for habitability, according to the study's authors.

The Medusae Fossae Formation is a massive, unusual deposit of soft rock near Mars's equator, with undulating hills and abrupt mesas. Scientists first observed the Medusae Fossae with NASA's Mariner spacecraft in the 1960s but were perplexed as to how it formed.

Now, new research suggests the formation was deposited during explosive volcanic eruptions on the Red Planet more than 3 billion years ago. The formation is about one-fifth as large as the continental United States and 100 times more massive than the largest explosive volcanic deposit on Earth, making it the largest known explosive volcanic deposit in the solar system, according to the study's authors.

An isolated hill in the Medusae Fossae Formation. The effect of wind erosion on this hill is evident by its streamlined shape. 
HRSC_2.png
Credit: High Resolution Stereo Camera/European Space Agency.

"This is a massive deposit, not only on a Martian scale, but also in terms of the solar system, because we do not know of any other deposit that is like this," said Lujendra Ojha, a planetary scientist at Johns Hopkins University in Baltimore and lead author of the new study published in the Journal of Geophysical Research: Planets, a journal of the American Geophysical Union.

Formation of the Medusae Fossae would have marked a pivotal point in Mars's history, according to the study's authors. The eruptions that created the deposit could have spewed massive amounts of climate-altering gases into Mars's atmosphere and ejected enough water to cover Mars in a global ocean more than 9 centimeters (4 inches) thick, Ojha said.

A 13-kilometer (8-mile) diameter crater being infilled by the Medusae Fossae Formation. 
HRSC_3.png
Credit: High Resolution Stereo Camera/European Space Agency

Greenhouse gases exhaled during the eruptions that spawned the Medusae Fossae could have warmed Mars's surface enough for water to remain liquid at its surface, but toxic volcanic gases like hydrogen sulfide and sulfur dioxide would have altered the chemistry of Mars's surface and atmosphere. Both processes would have affected Mars's potential for habitability, Ojha said.

Determining the source of the rock

The Medusae Fossae Formation consists of hills and mounds of sedimentary rock straddling Mars's equator. Sedimentary rock forms when rock dust and debris accumulate on a planet's surface and cement over time.

Scientists have known about the Medusae Fossae for decades, but were unsure whether wind, water, ice or volcanic eruptions deposited rock debris in that location.

Previous radar measurements of Mars's surface suggested the Medusae Fossae had an unusual composition, but scientists were unable to determine whether it was made of highly porous rock or a mixture of rock and ice. In the new study, Ojha and a colleague used gravity data from various Mars orbiter spacecraft to measure the Medusae Fossae's density for the first time. They found the rock is unusually porous: it's about two-thirds as dense as the rest of the Martian crust. They also used radar and gravity data in combination to show the Medusae Fossae's density cannot be explained by the presence of ice, which is much less dense than rock.

A global geographic map of Mars, with the location of the Medusae Fossae Formation circled in red. 
Mars_geographical_map.jpg
Credit: MazzyBor, CC BY-SA 4.0 via Wikimedia Commons

Because the rock is so porous, it had to have been deposited by explosive volcanic eruptions, according to the researchers. Volcanoes erupt in part because gases like carbon dioxide and water vapor dissolved in magma force the molten rock to rise to the surface. Magma containing lots of gas explodes skyward, shooting jets of ash and rock into the atmosphere.

Ash from these explosions plummets to the ground and streams downhill. After enough time has passed, the ash cements into rock, and Ojha suspects this is what formed the Medusae Fossae. As much as half of the soft rock originally deposited during the eruptions has eroded away, leaving behind the hills and valleys seen in the Medusae Fossae today.

Understanding Mars's interior

The new findings suggest the Martian interior is more complex than scientists originally thought, according to Ojha. Scientists know Mars has some water and carbon dioxide in its crust that allow explosive volcanic eruptions to happen on its surface, but the planet's interior would have needed massive amounts of volatile gases - substances that become gas at low temperatures - to create a deposit of this size, he said.

"If you were to distribute the Medusae Fossae globally, it would make a 9.7-meter (32-foot) thick layer." Ojha said. "Given the sheer magnitude of this deposit, it really is incredible because it implies that the magma was not only rich in volatiles and also that it had to be volatile-rich for long periods of time."

This graphic shows the relative size of the Medusae Fossae Formation compared to Fish Canyon Tuff, the largest explosive volcanic deposit on Earth.
018_29552_Medusa-Fossae-Infographic.jpg
Credit: AGU
The new study shows the promise of gravity surveys in interpreting Mars's rock record, according to Kevin Lewis, a planetary scientist at Johns Hopkins University and co-author of the new study. "Future gravity surveys could help distinguish between ice, sediments and igneous rocks in the upper crust of the planet," Lewis said.
 


Contacts and sources:
Lauren Lipuma
The American Geophysical Union

Researchers Map Brain Of Blind Patient Who Can See Motion

 Neuroscientists at Western University’s Brain and Mind Institute, have confirmed and detailed a rare case of a blind woman able to see objects – but only if in motion.

A team led by neuropsychologist Jody Culham has conducted the most extensive analysis and brain mapping to date of a blind patient, to help understand the remarkable vision of a 48-year-old Scottish woman, Milena Canning.

Neuropsychologist Jody Culham of the Brain and Mind Institute at Western University in London, Canada, led research into the brain of a blind woman able to se the motion of objects but not the objects themselves.

Credit: Western University

Canning lost her sight 18 years ago after a respiratory infection and series of strokes. Months after emerging blind from an eight-week coma, she was surprised to see the glint of a sparkly gift bag, like a flash of green lightning.

Then she began to perceive, sporadically, other moving things: her daughter’s ponytail bobbing when she walked, but not her daughter’s face; rain dripping down a window, but nothing beyond the glass; and water swirling down a drain, but not a tub already full with water.

Glaswegian ophthalmologist Gordon Dutton referred Canning to the Brain and Mind Institute in London, Canada, where tests by Culham’s team included functional Magnetic Resonance Imaging (fMRI) to examine the real-time structure and workings of her brain.

They determined Canning has a rare phenomenon called Riddoch syndrome – in which a blind person can consciously see an object if moving but not if stationary.

“She is missing a piece of brain tissue about the size of an apple at the back of her brain – almost her entire occipital lobes, which process vision,” says Culham, a professor in the Department of Psychology and Graduate Program in Neuroscience.

“In Milena’s case, we think the ‘super-highway’ for the visual system reached a dead end. But rather than shutting down her whole visual system, she developed some ‘back roads’ that could bypass the superhighway to bring some vision – especially motion – to other parts of the brain.”

In essence, Canning’s brain is taking unexpected, unconventional detours around damaged pathways.

During the study, Canning was able to recognize the motion, direction, size and speed of balls rolled towards her; and to command her hand to open, intercept and grab them at exactly the right time. She could navigate around chairs.

Yet she inconsistently identified an object’s colour, and was able only half the time to detect whether someone’s hand in front of her showed thumb-up or thumb-down.

“This work may be the richest characterization ever conducted of a single patient’s visual system,” says Culham. “She has shown this very profound recovery of vision, based on her perception of motion.”

The research shows the remarkable plasticity of the human brain in finding work-arounds after catastrophic injuries. And it suggests conventional definitions of ‘sight’ and ‘blindness’ are fuzzier than previously believed.

“Patients like Milena give us a sense of what is possible and, even more importantly, they give us a sense of what visual and cognitive functions go together,” Culham says.

For Canning, the research at BMI helps explain more about what she perceives and how her brain is continuing to change.She is able to navigate around chairs, can see a bright-shirted soccer goalie and can see steam rising from her morning cup of coffee, for example.

“I can’t see like normal people see or like I used to see. The things I’m seeing are really strange. There is something happening and my brain is trying to rewire itself or trying different pathways,” Canning says.

The research is newly publishedin the journal Neuropsychologia.




Contacts and sources:
University of Western Ontario

Citation: Psychophysical and neuroimaging responses to moving stimuli in a patient with the Riddoch phenomenon due to bilateral visual cortex lesions.
Michael J. Arcaro, Lore Thaler, Derek J. Quinlan, Simona Monaco, Sarah Khan, Kenneth F. Valyear, Rainer Goebel, Gordon N. Dutton, Melvyn A. Goodale, Sabine Kastner, Jody C. Culham. Neuropsychologia, 2018; DOI: 10.1016/j.neuropsychologia.2018.05.008

True Origin of Ancient Turquoise Unveiled

The true source of turquoise used by ancient Mesoamerican people has been found and it is not what scientists thought.

New research published June 13th in the journal Science Advances overturns more than a century of thought about the source of turquoise used by ancient civilizations in Mesoamerica, the vast region that extends from Central Mexico to Central America. For more than 150 years, scholars have argued that the Aztec and Mixtec civilizations, which revered the precious, blue-green mineral, acquired it through import from the American Southwest. However, extensive geochemical analyses reveal that the true geologic source of Aztec and Mixtec turquoise lies within Mesoamerica.

This is a close up view of Mixteca-style mask decorated with turquoise mosaic from the collections of the Smithsonian Institution-National Museum of the American Indian. NMAI Catalog #10/8712.

Credit:  Alyson M. Thibodeau

Geochemist Alyson Thibodeau, assistant professor of earth sciences at Dickinson College, and a team of researchers from the University of Arizona, California State University at San Bernardino, and the Museo del Templo Mayor in Mexico City, measured the isotopic signatures of Mesoamerican turquoise artifacts associated with both the Aztecs and Mixtecs. These isotopic signatures function like fingerprints that can be used to determine the geologic origins of the turquoise.

Specifically, Thibodeau and her research team carried out analyses of lead and strontium isotopes on fragments of turquoise-encrusted mosaics, which are one of the most iconic forms of ancient Mesoamerican art. Their samples include dozens of turquoise mosaic tiles excavated from offerings within the Templo Mayor, the ceremonial and ritual center of the Aztec empire, and which is located in present-day Mexico City.

This is a close up view of Mixteca-style shield decorated with turquoise mosaic from the collections of the Smithsonian Institution-National Museum of the American Indian. NMAI Catalog #10/8708. 
Credit:  Frances F. Berdan

 They also analyzed five tiles associated with Mixteca-style objects held by the Smithsonian's National Museum of the American Indian. The analyses revealed that turquoise artifacts had isotopic signatures consistent with geology of Mesoamerica, not the Southwestern United States.

"This work revises our understanding of these relatively rare objects and provides a new perspective on the availability of turquoise, which was a highly valued luxury resource in ancient Mesoamerica," said Thibodeau. The work is the result of a decade-long collaboration between archaeologists and isotope geochemists to understand the nature of turquoise circulation and trade across southwestern North America. In earlier published research, Thibodeau showed that isotopic signatures could distinguish among turquoise deposits across the southwestern U.S. and identified the geologic sources of turquoise artifacts from archaeological sites in Arizona and New Mexico.

This is a reconstructed turquoise mosaic disk from Offering 99 in the Templo Mayor.
 
Photo by Oliver Santana. Reproduced with permission from Editorial Raices.

Thibodeau said that long-standing assumption that Mesoamerican civilizations imported turquoise from the Southwest had not been fully substantiated with evidence and that the new geochemical measurements unveil a different story. "These findings potentially re-shape our understanding of both the nature and extent of long-distance contacts between Mesoamerican and Southwestern societies, said Thibodeau. "I hope this inspires people to be skeptical of claims."




Contacts and sources:
Christine Baksi
Dickinson College


Citation: Was Aztec and Mixtec turquoise mined in the American Southwest?
Alyson M. Thibodeau, Leonardo López Luján, David J. Killick, Frances F. Berdan, Joaquin Ruiz. Science Advances, 2018; 4 (6): eaas9370 DOI: 10.1126/sciadv.aas9370

What Saved The West Antarctic Ice Sheet 10,000 Years Ago Won’t Save It Today 

The retreat of the West Antarctic ice masses after the last Ice Age was reversed surprisingly about 10,000 years ago, scientists found. This is in stark contrast to previous assumptions. In fact, it was the shrinking itself that stopped the shrinking: relieved from the weight of the ice, the Earth crust lifted and triggered the re-advance of the ice sheet. However, this mechanism is much too slow to prevent dangerous sea-level rise caused by West Antarctica’s ice-loss in the present and near future. Only rapid greenhouse-gas emission reductions can.


West Antarctica: The maximum ice sheet extension is shown in green, the minimum extent 10,000 years ago in red, and the modern grounding line after the rebound in orange.
What saved the West Antarctic Ice Sheet 10,000 years ago will not save it today
 Fig.: Albrecht/PIK (cutout)

“The warming after the last Ice Age made the ice masses of West Antarctica dwindle,” says Torsten Albrecht from the Potsdam Institute for Climate Impact Research, one of the three lead authors of the study now published in the scientific journal Nature. “It retreated inland by more than 1,000 kilometers in a period of 1,000 years in large parts of this region – on geological time-scales, this is really high-speed. But now we detected that this process at some point got partially reversed. Instead of potential collapse, the ice sheet grew again by up to 400 kilometers. This is a limited, yet amazing self-induced stabilization. However, it took a whopping 10,000 years, up until now. Given the speed of current climate-change from burning fossil fuels, the mechanism we detected unfortunately does not work fast enough to save today’s ice sheets from melting and causing seas to rise.”

The team was able to find out why the rebound happened in West Antarctica. It is well-known that the Earth crust can get depressed by the weight of kilometer-thick ice on it – when the ice disappears, the ground lifts up. This is called isostatic rebound. However, this depends on the complicated characteristics of the Earth mantle in a given region – scientists for instance talk about viscosity. So far it was not known that the Earth crust in West Antarctica lifted in a way that made the shrinking ice re-advance. Previously, researchers assumed that after the last glacial maximum West Antarctica’s ice retreated continuously. Now it seems they have been generally right about the retreat, but have not fully grasped its dynamics.

Three sources of evidence: computer simulations, ice radar data, subglacial sediments
Credit: Potsdam Institute

“When I observed the re-growth in our numerical computer simulations of Western Antarctica, I first thought this might be a flaw – it looked so different from what you find in the text books,” says Torsten Albrecht. “So I started figuring out the involved interactions between the ice, ocean and Earth and their typical time scales.” In fact, the computer simulations turned out to help making sense out of observational data that other scientists found who had not relation to the work of the Potsdam modeling team – but were equally irritated at first about their respective findings.

During a trip to Antarctica to study ancient ice flows, Jonathan Kingslake and colleagues from Columbia University’s Lamont-Doherty Earth Observatory, based in New York, towed a radar device across the ice. To their surprise, the radar spotted cracks in the ice where there shouldn’t be any. “It was just bizarre,” says Kingslake, who is one of the study’s three lead-authors. “We hadn’t seen these kinds of structure near the base of an ice sheet before.” Further analyses of the signals revealed that the ice on the rocky ground must have been stretching or squishing rapidly, whereas this was so far considered a slow-moving area.

In yet another independent investigation, scientists looked into sediments recovered by drilling through many layers of ice to where it is grounded on rocks. The area was thought to be covered by grounded ice since the past Ice Age. But the team of Reed Scherer from Northern Illinois University, the third lead-author of the study now published, found organic material beneath the ice – the remains of tiny sea creatures long dead. This indicates that this area was connected to the ocean more recently than anybody thought. This is due to the rapid retreat and slow re-growth of the ice thousands of years ago.

Uplift won't help regrow the ice until long after coastal cities have felt the effects of sea level rise

A number of factors influences the ice-sheet behavior under warming. In the studied region sea mountains turned out to be rather important for the ice dynamics. The peaks of these mountains underneath the floating ice shelves reach up from the bottom of the ocean. When the bottom rises they can become ice rises within the ice shelf. Since they’re made of solid rock, they increase the stability of the ice sheet. The scientists call this a buttressing effect. Conditions for ice re-growth might be less favorable in other areas.

Yet it is the time-scale that is key in the end. “What happened roughly 10.000 years ago might not dictate where we’re going in our carbon dioxide-enhanced world, in which the oceans are rapidly warming in the Polar regions,” says Scherer. “If the ice sheet were to dramatically retreat now, triggered by anthropogenic warming, the uplift process won’t help regrow the ice sheet until long after coastal cities have felt the effects of sea level rise.”


Contacts and sources:
\
Potsdam Institute for Climate Impact Research (PIK)

Citation: Extensive retreat and re-advance of the West Antarctic Ice Sheet during the Holocene.
J. Kingslake, R. P. Scherer, T. Albrecht, J. Coenen, R. D. Powell, R. Reese, N. D. Stansell, S. Tulaczyk, M. G. Wearing, P. L. Whitehouse. Nature, 2018; DOI: 10.1038/s41586-018-0208-x
Mysterious features seen in light emitted from active galactic nuclei may be due to partial obscuring by dust clouds, according to new study

An artist’s impression of what an active galactic nucleus might look like close up. The accretion disk produces the brilliant light in the center. The broad-line region is just above the accretion disk and lost in the glare. Dust clouds are being driven upward by the intense radiation.

Image credit: Peter Z. Harrington

Many large galaxies have a bright central region called an active galactic nucleus (AGN), powered by matter spiraling into a supermassive black hole. Gas clouds in an area around the AGN known as the "broad-line region" emit light at characteristic wavelengths, but the complexity and variability of these emissions has been a longstanding puzzle for astrophysicists.

A new analysis by researchers at UC Santa Cruz, published June 14 in Monthly Notices of the Royal Astronomical Society, explains these and other puzzling features of active galactic nuclei as the result of small clouds of dust that can partially obscure the innermost regions of AGNs.

"We've shown that a lot of mysterious properties of active galactic nuclei can be explained by these small dusty clouds causing changes in what we see," said first author Martin Gaskell, a research associate in astronomy and astrophysics at UC Santa Cruz.

The findings have important implications because researchers use the optical emissions from the broad-line region to make inferences about the behavior of the gases in the inner regions around a supermassive black hole.

"The emission from this gas is one of the best sources of information about the mass of a black hole and how it is growing. However, the nature of this gas is poorly understood," Gaskell said.

Coauthor Peter Harrington, a UCSC graduate student who began work on the project as an undergraduate, explained that gas spiraling toward a galaxy's central black hole forms a flat accretion disk, and the superheated gas in the accretion disk emits intense thermal radiation. Some of that light is "reprocessed" (absorbed and re-emitted) by hydrogen and other gases swirling above and below the accretion disk in the broad-line region. Above and beyond this is a region of dust.

"Once the dust crosses a certain threshold it is subjected to the strong radiation from the accretion disk," said Harrington. "This radiation is so intense that it blows the dust away from the disk, resulting in a clumpy outflow of dust clouds starting at the outer edge of the broad-line region."

The effect of the dust clouds on the light emitted is to make the light coming from behind them look fainter and redder, just as Earth's atmosphere makes the sun look fainter and redder at sunset. In their paper, Gaskell and Harrington present several lines of observational evidence supporting the existence of such dust clouds in the inner regions of active galactic nuclei. They developed a computer code to model the effects of dust clouds on observations of the broad-line region.

"We've written the code so we can adjust parameters like the distribution of gas in the broad-line region, how fast it's moving, and the orientation of the system, and then we can introduce dust clouds and see how they affect the emission-line profiles," Harrington said.

The results show that by including dust clouds in their model, it can replicate many features of emission from the broad-line region that have long puzzled astrophysicists. Rather than the gas having a changing, asymmetrical distribution that is hard to explain, the gas is simply in a uniform, symmetric, turbulent disk around the black hole. The apparent asymmetries and changes are due to dust clouds passing in front of the broad-line region and making the regions behind them look fainter and redder.

"We think it is a much more natural explanation of the asymmetries and changes than other more exotic theories, such as binary black holes, that have been invoked to explain them," Gaskell said. "Our explanation lets us retain the simplicity of the standard AGN model of matter spiraling onto a single black hole."



Contacts and sources:
Tim Stephens
University of California - Santa Cruz



Citation: Partial dust obscuration in active galactic nuclei as a cause of broad-line profile and lag variability, and apparent accretion disc inhomogeneities.
C Martin Gaskell, P Z Harrington. Monthly Notices of the Royal Astronomical Society, 2018; 478 (2): 1660 DOI: 10.1093/mnras/sty848

Fleeing the Light: Wildlife Becoming More Nocturnal to Avoid People




A new study published in Science finds that mammals are becoming more nocturnal in response to human activity.   Human activity is causing the planet’s mammals to flee daylight for the protection of night, according to a the new study from UC Berkeley.

The study, published in the journal Science, and supported in part by the National Science Foundation, represents the first effort to quantify the global effects of human activity on the daily activity patterns of wildlife. Its results highlight the powerful and widespread process by which animals alter their behavior alongside people: human disturbance is creating a more nocturnal natural world.

“Catastrophic losses in wildlife populations and habitats as a result of human activity are well documented, but the subtler ways in which we affect animal behavior are more difficult to detect and quantify,” said Berkeley PhD candidate and study lead author Kaitlyn Gaynor.

This study represents the first effort to quantify the global effects of human activity on the daily activity patterns of wildlife.

Photo by Jamie Hall.


Gaynor, along with co-authors Justin Brashares and Cheryl Hojnowski of UC Berkeley, and Neil Carter of Boise State University, applied a meta-analysis approach, using data for 62 species across six continents to look for global shifts in the timing of daily activity of mammals in response to humans. These data were collected by various approaches, including remotely triggered cameras, GPS and radio collars, and direct observation. For each species in each study site, the authors quantified the difference in animal nocturnality under low and high human disturbance.

On average, mammals were 1.36 times more nocturnal in response to human disturbance. This means that an animal that naturally split its activity evenly between the day and night increased its nighttime activity to 68% around people. This finding was consistent across carnivore and herbivore species of all body sizes greater than 1 kg (small mammals were not included in the study). The pattern also held across different types of human disturbance, including activities such as hunting, hiking, mountain biking, and infrastructure such as roads, residential settlement, and agriculture.

“While we expected to find a trend towards increased wildlife nocturnality around people, we were surprised by the consistency of the results around the world,” said Gaynor. “Animals responded strongly to all types of human disturbance, regardless of whether people actually posed a direct threat, suggesting that our presence alone is enough to disrupt their natural patterns of behavior.”

two deer stand in an urban street at night under street lamps
Credit: Jamie Hallw

According to Brashares, a professor in the Department of Environmental Science, Policy, and Management and the study’s senior author, the consequences of the behavioral shift in wildlife can be seen through contrasting lenses. “On the positive side, the fact that wildlife is adapting to avoid humans temporally could be viewed as a path for coexistence of humans and wild animals on an increasingly crowded planet,” said Brashares. “However, animal activity patterns reflect millions of years of adaptation—it’s hard to believe we can simply squeeze nature into the dark half of each day and expect it to function and thrive.”

The authors describe a range of potential negative consequences of the shifts they report in wildlife, including mismatches between the environment and an animal’s traits, disruption of normal foraging behavior, increased vulnerability to non-human predators, and heightened competition. They point out, however, that while many of the studies included in their analysis documented a clear increase in nocturnal activity, few examined the consequences for individual animals, populations, or ecosystems.

“We hope our findings will open up new avenues for wildlife research in human-dominated landscapes. We still have a lot to learn about the implications of altered activity patterns for the management of wildlife populations, interactions between species, and even human-induced evolution,” said Gaynor.



Contacts and sources:
Mackenzie Smith
University of California - Berkeley

Citation: The influence of human disturbance on wildlife nocturnality.
Kaitlyn M. Gaynor, Cheryl E. Hojnowski, Neil H. Carter, Justin S. Brashares. Science, 2018; 360 (6394): 1232 DOI: 10.1126/science.aar7121

New Cathode Triples the Energy Storage of Lithium-Ion Batteries

Scientists have synthesized a new cathode material from iron fluoride that surpasses the capacity limits of traditional lithium-ion batteries.

As the demand for smartphones, electric vehicles, and renewable energy continues to rise, scientists are searching for ways to improve lithium-ion batteries—the most common type of battery found in home electronics and a promising solution for grid-scale energy storage. Increasing the energy density of lithium-ion batteries could facilitate the development of advanced technologies with long-lasting batteries, as well as the widespread use of wind and solar energy. Now, researchers have made significant progress toward achieving that goal.

A collaboration led by scientists at the University of Maryland (UMD), the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, and the U.S. Army Research Lab have developed and studied a new cathode material that could triple the energy density of lithium-ion battery electrodes. Their research was published on June 13 in Nature Communications.

Substituting the cathode material with oxygen and cobalt prevents lithium from breaking chemical bonds and preserves the material's structure.




Credit: DOE


“Lithium-ion batteries consist of an anode and a cathode,” said Xiulin Fan, a scientist at UMD and one of the lead authors of the paper. “Compared to the large capacity of the commercial graphite anodes used in lithium-ion batteries, the capacity of the cathodes is far more limited. Cathode materials are always the bottleneck for further improving the energy density of lithium-ion batteries.”

Scientists at UMD synthesized a new cathode material, a modified and engineered form of iron trifluoride (FeF3), which is composed of cost-effective and environmentally benign elements—iron and fluorine. Researchers have been interested in using chemical compounds like FeF3 in lithium-ion batteries because they offer inherently higher capacities than traditional cathode materials.

“The materials normally used in lithium-ion batteries are based on intercalation chemistry,” said Enyuan Hu, a chemist at Brookhaven and one of the lead authors of the paper. “This type of chemical reaction is very efficient; however, it only transfers a single electron, so the cathode capacity is limited. Some compounds like FeF3 are capable of transferring multiple electrons through a more complex reaction mechanism, called a conversion reaction.”

Brookhaven scientists Enyuan Hu and Sooyeon Hwang are pictured at the Center for Functional Nanomaterial's TEM facility where the researchers viewed the cathode material at a resolution of 0.1 nanometers.
 Credit: DOE


Despite FeF3’s potential to increase cathode capacity, the compound has not historically worked well in lithium-ion batteries due to three complications with its conversion reaction: poor energy efficiency (hysteresis), a slow reaction rate, and side reactions that can cause poor cycling life. To overcome these challenges, the scientists added cobalt and oxygen atoms to FeF3 nanorods through a process called chemical substitution. This allowed the scientists to manipulate the reaction pathway and make it more “reversible.”

“When lithium ions are inserted into FeF3, the material is converted to iron and lithium fluoride,” said Sooyeon Hwang, a co-author of the paper and a scientist at Brookhaven’s Center for Functional Nanomaterials (CFN). “However, the reaction is not fully reversible. After substituting with cobalt and oxygen, the main framework of the cathode material is better maintained and the reaction becomes more reversible.”

To investigate the reaction pathway, the scientists conducted multiple experiments at CFN and the National Synchrotron Light Source II (NSLS-II)—two DOE Office of Science User Facilities at Brookhaven.

First at CFN, the researchers used a powerful beam of electrons to look at the FeF3 nanorods at a resolution of 0.1 nanometers—a technique called transmission electron microscopy (TEM). The TEM experiment enabled the researchers to determine the exact size of the nanoparticles in the cathode structure and analyze how the structure changed between different phases of the charge-discharge process. They saw a faster reaction speed for the substituted nanorods.

“TEM is a powerful tool for characterizing materials at very small length scales, and it is also able to investigate the reaction process in real time,” said Dong Su, a scientist at CFN and a co-corresponding author of the study. “However, we can only see a very limited area of the sample using TEM. We needed to rely on the synchrotron techniques at NSLS-II to understand how the whole battery functions.”

At NSLS-II’s X-ray Powder Diffraction (XPD) beamline, scientists directed ultra-bright x-rays through the cathode material. By analyzing how the light scattered, the scientists could “see” additional information about the material’s structure.

“At XPD, we conducted pair distribution function (PDF) measurements, which are capable of detecting local iron orderings over a large volume,” said Jianming Bai, a co-author of the paper and a scientist at NSLS-II. “The PDF analysis on the discharged cathodes clearly revealed that the chemical substitution promotes electrochemical reversibility.”

Combining highly advanced imaging and microscopy techniques at CFN and NSLS-II was a critical step for assessing the functionality of the cathode material.

The University of Maryland team, pictured from left to right: Xiulin Fan, Xiao Ji, Fudong Han, and Zhaohui Ma.

 Credit: DOE


“We also performed advanced computational approaches based on density functional theory to decipher the reaction mechanism at an atomic scale,” said Xiao Ji, a scientist at UMD and co-author of the paper. “This approach revealed that chemical substitution shifted the reaction to a highly reversible state by reducing the particle size of iron and stabilizing the rocksalt phase.”Scientists at UMD say this research strategy could be applied to other high energy conversion materials, and future studies may use the approach to improve other battery systems.

This study was supported by the U.S. Army Research Laboratory and DOE’s Office of Energy Efficiency and Renewable Energy. Operations at CFN and NSLS-II are supported by DOE’s Office of Science

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.


Contacts and sources:

DOE/Brookhaven National Laboratory 


Citation: "High energy-density and reversibility of iron fluoride cathode enabled via an intercalation-extrusion reaction"
Xiulin Fan, Enyuan Hu, Xiao Ji, Yizhou Zhu, Fudong Han, Sooyeon Hwang, Jue Liu, Seongmin Bak, Zhaohui Ma, Tao Gao, Sz-Chian Liou, Jianming Bai, Xiao-Qing Yang, Yifei Mo, Kang Xu, Dong Su, Chunsheng Wang.. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-04476-2

Link Found Between Allergen in Red Meat and Heart Disease



A team of researchers says it has linked sensitivity to an allergen in red meat to the buildup of plaque in the arteries of the heart. While high saturated fat levels in red meat have long been known to contribute to heart disease for people in general, the new finding suggests that a subgroup of the population may be at heightened risk for a different reason – a food allergen. The study, which is supported by the National Heart, Lung, and Blood Institute, part of the National Institutes of Health, appears in Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB), a peer-reviewed journal of the American Heart Association.

“This novel finding from a small group of subjects from Virginia raises the intriguing possibility that allergy to red meat may be an underrecognized factor in heart disease,” said study leader Coleen McNamara, M.D., a professor of medicine in the Cardiovascular Research Center of the University of Virginia Health System, Charlottesville. “These preliminary findings underscore the need for further clinical studies in larger populations from diverse geographic regions and additional laboratory work.”

Shown are cross-sectional ultrasound images of coronary arteries from patients enrolled in the study. Plaque buildup (colored areas) in an artery from a patient that lacks sensitivity to red meat allergen (left) is much lower than plaque levels in an artery from a patient with sensitivity to red meat allergen (right). 
Scan of cross-sectional ultrasound images of coronary arteries
Credit: Angela Taylor, M.D., University of Virginia Health System

The number of people with red meat allergies in the United States is unclear, but researchers estimate that it may be 1 percent of the population in some areas. The number of people who develop blood antibodies to the red meat allergen without having full-blown symptoms is much higher — as much as 20 percent of the population in some areas, the researchers say.

Only in recent years did scientists identify the main allergen in red meat, called galactose-α-1,3-galactose, or alpha-Gal, a type of complex sugar. They also found that a tick — the Lone Star tick — sensitizes people to this allergen when it bites them. That is why red meat allergies tend to be more common where these ticks are more prevalent, such as the Southeastern United States, but also extending to other areas, including Long Island, New York.

Researchers have suspected for some time that allergens can trigger certain immunological changes that might be associated with plaque buildup and artery blockages, but no one had identified a specific substance that is responsible for this effect. In the current study, researchers showed for the first time that a specific blood marker for red meat allergy was associated with higher levels of arterial plaque, or fatty deposits on the inner lining of the arteries. The blood marker they identified is a type of antibody (immunoglobulin or IgE) that is specific to the alpha-Gal allergen.

To identify this blood marker, the researchers analyzed blood samples from 118 adults and detected antibodies to alpha-Gal, indicating sensitivity to red meat, in 26 percent of them. Using an imaging procedure, the researchers found that the quantity of plaque was 30 percent higher in the alpha-Gal sensitized patients than in the non-sensitized patients. These plaques, a hallmark of atherosclerosis (hardening of the arteries), also tended to be more structurally unstable, which means that they have an increased likelihood of causing heart attack and stroke.

The evidence for a link between red meat allergens and coronary artery disease is still preliminary, the researchers noted, so they plan to conduct detailed animal and human studies to confirm their initial findings. Currently, the only treatment for red meat allergy once it is diagnosed is strict avoidance of red meat.

“While more studies are needed, the current work provides a potential new approach or target for preventing or treating heart disease in a subgroup of people who are sensitized to red meat,” said Ahmed Hasan, M.D., Ph.D., a medical officer and program director in NHLBI’s Atherothrombosis & Coronary Artery Disease Branch.

For now, consumers are encouraged to follow current recommendations for a heart-healthy lifestyle. This includes adapting a healthy diet, such as eating plenty of vegetables, fruits, whole grains, and other heart-healthy foods. Lean red meats can be part of a heart healthy diet for those who are not allergic. Other heart-healthy lifestyle changes also include aiming for a healthy weight, managing stress, getting more exercise, and quitting smoking.

In addition to funding from NHLBI, this study was also funded by the National Institute of Allergy and Infectious Diseases (NIAID). NIH funding support includes the following grants: (KO8-AI085190, K23-HL093118, RO1-AI 20565, PO1-HL55798, RO1-HL136098-01, RO1-HL107490)




Contacts and sources:
 NIH/National Heart, Lung and Blood Institute

E-textiles Will Control Home Appliances with the Swipe of a Finger




Electronic textiles could allow a person to control household appliances or computers from a distance simply by touching a wristband or other item of clothing — something that could be particularly helpful for those with limited mobility. Now researchers, reporting in ACS Nano, have developed a new type of e-textile that is self-powered, highly sensitive and washable. 

Credit; ACS



E-textiles are not new, but most existing versions have poor air permeability, can’t be laundered or are too costly or complex to mass-produce. Jiaona Wang, Hengyu Guo, Congju Li and coworkers wanted to develop an E-textile that overcomes all of these limitations and is highly sensitive to human touch.

The researchers made a self-powered triboelectric nanogenerator by depositing an electrode array of conductive carbon nanotubes on nylon fabric. To make the E-textile washable, they incorporated polyurethane into the carbon nanotube ink, which made the nanotubes firmly adhere to the fabric. 

A video of an e-wristband in action 

Credit; American Chemical Society

They covered the array with a piece of silk and fashioned the textile into a wristband. When swiped with a finger in different patterns, the E-textile generated electrical signals that were coupled to computers to control programs, or to household objects to turn on lights, a fan or a microwave from across the room. The E-textile is breathable for human skin, washable and inexpensive to produce on a large scale, the researchers say.

The authors acknowledge funding from the Beijing Natural Science Foundation, theNational Natural Science Foundation, National Key R&D Project from Minister of Science and Technology, the Programs for Beijing Science and Technology Leading Talent, the Beijing Hundred, Thousand and Ten Thousand Talent Project, the General Program of Science and Technology Development Project of Beijing Municipal Education Commission of China, Beijing Institute of Fashion Technology and the “Thousands Talents” Program for Pioneer Researcher and His Innovation Team.



Contacts and sources:
Katie Cottingham, Ph.D.
American Chemical Society


ACS Nano

The One Cell That Regenerates Entire Organism Discovered



Researchers at the Stowers Institute for Medical Research have captured the one cell that is capable of regenerating an entire organism. For over a century, scientists have witnessed the effects of this cellular marvel, which enables creatures such as the planarian flatworm to perform death-defying feats like regrowing a severed head. But until recently, they lacked the tools necessary to target and track this cell, so they could watch it in action and discover its secrets.

Now, by pioneering a technique that combines genomics, single-cell analysis, flow cytometry and imaging, scientists have isolated this amazing regenerative cell – a subtype of the long-studied adult pluripotent stem cell – before it performs its remarkable act. The findings, published in the June 14, 2018, issue of the journal Cell, will likely propel biological studies on highly regenerative organisms like planarians and also inform regenerative medicine efforts for other organisms like humans that have less regenerative capacity.

“This is the first time that an adult pluripotent stem cell has been isolated prospectively,” says Alejandro Sánchez Alvarado, Ph.D., an investigator at the Stowers Institute and Howard Hughes Medical Institute and senior author of the study. “Our finding essentially says that this is no longer an abstraction, that there truly is a cellular entity that can restore regenerative capacities to animals that have lost it and that such entity can now be purified alive and studied in detail.”

Every multicellular organism is built from a single cell, which divides into two identical cells, then four, and so on. Each of these cells contains the exact same twisted strands of DNA, and is considered pluripotent – meaning it can give rise to all possible cell types in the body. But somewhere along the way, those starter cells – known as embryonic stem cells – resign themselves to a different fate and become skin cells, heart cells, muscle cells, or another cell type. In humans, no known pluripotent stem cells remain after birth. In planarians, they stick around into adulthood, where they become known as adult pluripotent stem cells or neoblasts. Scientists believe these neoblasts hold the secret to regeneration.

Though neoblasts have been the subject of scientific inquiry since the late 1800’s, only in the last couple of decades have scientists been able to characterize this powerful cell population using functional assays and molecular techniques. Their efforts showed that this seemingly homogenous cell population was actually a conglomeration of different subtypes, with different properties and different patterns of gene expression.

“We might have to transplant over a hundred individual cells into as many worms to find one that is truly pluripotent and can regenerate the organism,” says Sánchez Alvarado. “That's a lot of work, just to find the one cell that fits the functional definition of a true neoblast. And if we want to define it molecularly by identifying the genes that cell is expressing, we have to destroy the cell for processing. There was no way to do that and keep the cell alive to track it during regeneration.”

Sánchez Alvarado and his team began searching for a distinguishing characteristic that could identify this elusive cell ahead of time. One feature that had long been used to distinguish neoblasts from other cells is a stem cell marker known as piwi-1, so Postdoctoral Research Associate An Zeng, Ph.D., decided to start there. First, he separated the cells that expressed this marker from those that did not. Then he noticed the cells could be separated into two groups – one that expressed high levels of piwi (aptly called piwi-high) and another that expressed low levels of piwi (called piwi-low). When Zeng studied the members of these two groups, he found only those that were piwi-high fit the molecular definition of neoblasts. So he discarded the rest.

“This kind of simultaneous quantitative analysis of gene expression and protein levels had never been done before in planarians,” says Sánchez Alvarado. “We could not have done it without the amazing scientific support facilities here at Stowers, including molecular biology, flow cytometry, bioinformatics, and imaging groups. Many researchers had assumed that all cells expressing piwi-1 were true neoblasts, and it didn’t matter how much of the marker they expressed. We showed it did matter.”

Next, Zeng selected 8,000 or so of the piwi-high cells and analyzed their gene expression patterns. To his surprise, the cells fell not into just one or two, but 12 different subgroups. Through a process of elimination, Zeng excluded any subgroups with genetic signatures indicating that the cells were destined for a particular fate, like muscle or skin. That left him with two subgroups that could still be pluripotent, which he named Nb1 and Nb2.

Credit:  Stowers Institute for Medical Research


Planarian flatworm adult stem cells known as neoblasts can be clustered based on their gene expression profiles (left panel). A neoblast subpopulation termed Nb2 expresses the cell membrane protein TSPAN-1 (center panel, a representative Nb2 cell with TSPAN-1 protein shown in green and DNA in blue). Nb2 neoblasts can repopulate stem cell-depleted animals (right panel, representative animals at different time points after Nb2 single-cell transplants).

Conveniently, the cells in subgroup Nb2 expressed a gene coding for a member of the tetraspanin protein family, a group of evolutionarily ancient and poorly understood proteins that sit on the surface of cells. Zeng made an antibody that could latch onto this protein, pulling the cells that carried it out of a mixture of other suspected neoblasts. He then transplanted the single purified cell into a planarian that had been subjected to lethal levels of radiation. Not only did these cells repopulate and rescue the irradiated animals, but they did so 14 times more consistently than cells purified by older methods.

“We have enriched for a pluripotent stem cell population, which opens the door to a number of experiments that were not possible before,” says Sánchez Alvarado. “The fact that the marker we discovered is expressed not only in planarians but also in humans suggests that there are some conserved mechanisms that we can exploit. I expect those first principles will be broadly applicable to any organism that ever relied on stem cells to become what they are today. And that essentially is everybody.”

Other contributors from the Stowers Institute include Hua Li, Ph.D., Longhua Guo, Ph.D., Xin Gao, Ph.D., Sean McKinney, Ph.D., Yongfu Wang, Ph.D., Zulin Yu, Ph.D., Jungeun Park, Craig Semerad, Ph.D., Eric Ross, Li-Chun Cheng, Ph.D., Erin Davies, Ph.D., Kai Lei, Ph.D., Wei Wang, Ph.D., Anoja Perera, Kate Hall, Allison Peak, and Andrew Box.

The work was funded by the Stowers Institute for Medical Research, the Howard Hughes Medical Institute, and the National Institute of General Medical Sciences of the National Institutes of Health (award R37GM057260). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Lay Summary of Findings

The amazing freshwater flatworm known as planaria is a favorite of scientists who study regeneration in research organisms in the hopes of unlocking this property in humans. Over a century ago, they traced planaria’s regenerative powers to a special population of adult stem cells called neoblasts. But until recently, they lacked the tools necessary to hone in further on the individual cells truly capable of regeneration. In the June 14, 2018, issue of the journal Cell, researchers from the Stowers Institute for Medical Research published a study that combined genomics, single-cell analysis, and imaging to isolate this elusive cell. Postdoctoral Research Associate An Zeng, Ph.D., his advisor Alejandro Sánchez Alvarado, Ph.D., and their Stowers collaborators report that a molecule called TSPAN-1 that sits of the surface of cells can be used to purify regenerative neoblasts from similar cell types. These findings have important implications for advancing the study of stem cell biology and regenerative medicine.


Contacts and sources:
Stowers Institute for Medical Research



Citation: Prospectively Isolated Tetraspanin Neoblasts Are Adult Pluripotent Stem Cells Underlying Planaria Regeneration.
An Zeng, Hua Li, Longhua Guo, Xin Gao, Sean McKinney, Yongfu Wang, Zulin Yu, Jungeun Park, Craig Semerad, Eric Ross, Li-Chun Cheng, Erin Davies, Kai Lei, Wei Wang, Anoja Perera, Kate Hall, Allison Peak, Andrew Box, Alejandro Sánchez Alvarado. Cell, 2018; 173 (7): 1593 DOI: 10.1016/j.cell.2018.05.006

Saturday, June 16, 2018

Short Gamma-Ray Bursts Do Follow Binary Neutron Star Mergers Says New Research

Researchers at Oregon State University have confirmed that last fall’s union of two neutron stars did in fact cause a short gamma-ray burst. The binary neutron star (BNS) merger GW170817 was the first astrophysical source detected in gravitational waves and multiwavelength electromagnetic radiation.
The findings, published in Physical Review Letters, represent a key step forward in astrophysicists’ understanding of the relationship between binary neutron star mergers, gravitational waves and short gamma-ray bursts.

Commonly abbreviated as GRBs, gamma-ray bursts are narrow beams of electromagnetic waves of the shortest wavelengths in the electromagnetic spectrum. GRBs are the universe’s most powerful electromagnetic events, occurring billions of light years from Earth and able to release as much energy in a few seconds as the sun will in its lifetime.

Credit: OSU

GRBs fall into two categories, long duration and short duration. Long GRBs are associated with the death of a massive star as its core becomes a black hole and can last from a couple of seconds to several minutes.

Short GRBs had been suspected to originate from the merger of two neutron stars, which also results in a new black hole – a place where the pull of gravity from super-dense matter is so strong that not even light can escape. Up to 2 seconds is the time frame of a short GRB.

The term neutron star refers to the gravitationally collapsed core of a large star; neutron stars are the smallest, densest stars known. According to NASA, neutron stars’ matter is packed so tightly that a sugar-cube-sized amount of it weighs in excess of a billion tons.

In November 2017, scientists from U.S. and European collaborations announced they had detected an X-ray/gamma-ray flash that coincided with a blast of gravitational waves, followed by visible light from a new cosmic explosion called a kilonova.

Gravitational waves, a ripple in the fabric of time-space, were first detected in September 2015, a red-letter event in physics and astronomy that confirmed one of the main predictions of Albert Einstein’s 1915 general theory of relativity.

“A simultaneous detection of gamma rays and gravitational waves from the same place in the sky was a major milestone in our understanding of the universe,” said Davide Lazzati, a theoretical astrophysicist in the OSU College of Science. “The gamma rays allowed for a precise localization of where the gravitational waves were coming from, and the combined information from gravitational and electromagnetic radiation allows scientists to probe the binary neutron star system that’s responsible in unprecedented ways.”

Prior to Lazzati’s latest research, however, it had been an open question as to whether the detected electromagnetic waves were “a short gamma-ray burst, or just a short burst of gamma rays” – the latter being a different, weaker phenomenon.

In summer 2017, Lazzati’s team of theorists had published a paper predicting that, contrary to earlier estimates by the astrophysics community, short gamma-ray bursts associated with the gravitational emission of binary neutron star coalescence could be observed even if the gamma-ray burst was not pointing directly at Earth.

“X- and gamma rays are collimated, like the light of a lighthouse, and can be easily detected only if the beam points toward Earth,” Lazzati said. “Gravitational waves, on the other hand, are almost isotropic and can always be detected.”

Isotropic refers to being evenly transmitted in all directions.

“We argued that the interaction of the short gamma-ray burst jet with its surroundings creates a secondary source of emission called the cocoon,” Lazzati said. “The cocoon is much weaker than the main beam and is undetectable if the main beam points toward our instruments. However, it could be detected for nearby bursts whose beam points away from us.”

In the months following the November 2017 gravitational wave detection, astronomers continued to observe the location from which the gravitational waves came.

“More radiation came after the burst of gamma rays: radio waves and X-rays,” Lazzati said. “It was different from the typical short GRB afterglow. Usually there’s a short burst, a bright pulse, bright X-ray radiation, then it decays with time. This one had a weak gamma-ray pulse, and the afterglow was faint, brightened very quickly, kept brightening, then turned off.”

“But that behavior is expected when you’re seeing it from an off-axis observation point, when you’re not staring down the barrel of the jet,” he said. “The observation is exactly the behavior we predicted. We haven’t seen the murder weapon, we don’t have a confession, but the circumstantial evidence is overwhelming. This is doing exactly what we expected an off-axis jet would do and is convincing proof that binary neutron star mergers and short gamma-ray bursts are indeed related to each other.”





Contacts and sources:
Davide Lazzati, Steve Lundeberg
Oregon State University

Citation: Late Time Afterglow Observations Reveal a Collimated Relativistic Jet in the Ejecta of the Binary Neutron Star Merger GW170817
Davide Lazzati, Rosalba Perna, Brian J. Morsony, Diego Lopez-Camara, Matteo Cantiello, Riccardo Ciolfi, Bruno Giacomazzo, and Jared C. Workman
Phys. Rev. Lett. 120, 241103 – Published 13 June 2018
http://dx.doi.org/10.1103/PhysRevLett.120.241103

Lunar Meteorite Offers Proof of Theory about Water on the Moon, Ice May Be "Abundant" Below the Surface


A team of Japanese scientists led by Masahiro Kayama of Tohoku University's Frontier Research Institute for Interdisciplinary Sciences, has discovered a mineral known as moganite in a lunar meteorite found in a hot desert in northwest Africa.

This is significant because moganite is a mineral that requires water to form, reinforcing the belief that water exists on the Moon.

"Moganite is a crystal of silicon dioxide and is similar to quartz. It forms on Earth as a precipitate when alkaline water including SiO2 is evaporated under high pressure conditions," says Kayama. "The existence of moganite strongly implies that there is water activity on the Moon."

Credit:  Tohoku University

Kayama and his team analyzed 13 of the lunar meteorites using sophisticated methods to determine chemical compositions and structures of their minerals. These included electron microscopy for high-magnification, and micro-Raman spectroscopy to determine the structure of the minerals based on their atomic vibration.

Moganite was found in only one of those 13 samples, confirming the team's theory that it could not have formed in the African desert. "If terrestrial weathering had produced moganite in the lunar meteorite, there should be moganite present in all the samples that fell to Earth around the same time. But this was not the case," says Kayama.

He adds that part of the moganite had changed into the high-pressure SiO2 minerals stishovite and coesite, which he believes was most likely formed through heavy impact collisions on the Moon.

This is the first time that moganite has been detected in lunar rocks. The researchers say the meteorites probably came from an area of the Moon called Procellarum Terrane, and that the moganite was formed through the process of water evaporation in strong sunlight. Kayama's working theory is that deeper under the lunar surface, protected from the sun, crystals of water ice could be abundant.


Credit: Tohoku University

In recent years, space missions have found evidence of lunar water or ice concentrated at the poles where sunlight appears at a very narrow angle, leading to pockets of cold traps. This is the first time, however, that the scientists have found evidence of abundant water ice in the lunar subsurface at mid and lower latitudes.

Kayama's team estimates that the accumulation of water in the lunar soil is about 0.6 weight percent. If they are right, future lunar explorers would have easier access to the resource, which would greatly enhance the chances of the Moon hosting human settlement and infrastructure, and supporting a variety of industries within the next few decades.


Credit: Tohoku University

JAXA, the Japan Aerospace Exploration Agency, is said to be considering two future missions - a lunar pole landing mission in five years to look for water resources and a sample return mission from the far-side of the Moon in ten years.

In addition to testing for water in other silica minerals found, Kayama and his team also plan to study water from solar wind to the regolith soils and volcanic eruptions from the lunar mantle. "Solar wind-induced water can give us new insight into the history of sun activity, and volcanic water provides us with information of lunar evolution together with water," says Kayama, about his lab's next project. "It's all very exciting."




Contacts and sources:
Masahiro Kayama
Creative Interdisciplinary Research Division,
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University


Citation: Discovery of moganite in a lunar meteorite as a trace of H2O ice in the Moon's regolith
Authors: Masahiro Kayama, Naotaka Tomioka, Eiji Ohtani, Yusuke Seto, Hiroshi Nagaoka, Jens Götze, Akira Miyake, Shin Ozawa, Toshimori Sekine, Masaaki Miyahara, Kazushige Tomeoka, Megumi Matsumoto, Naoki Shoda, Naohisa Hirao, Takamichi Kobayashi
Journal: Science Advances
DOI: 10.1126/sciadv.aar4378
http://dx.doi.org/10.1126/sciadv.aar4378

Organics on Ceres Surprisingly High Concentrations, More Abundant Than Originally Thought

A new analysis of data from NASA’s Dawn mission suggests that organic matter may exist in surprisingly high concentrations on the dwarf planet’s surface.
Credit: NASA / Rendering by Hannah Kaplan

 Last year, scientists with NASA's Dawn mission announced the detection of organic material — carbon-based compounds that are necessary components for life — exposed in patches on the surface of the dwarf planet Ceres. Now, a new analysis of the Dawn data by Brown University researchers suggests those patches may contain a much higher abundance of organics than originally thought.

The findings, published recently in Geophysical Research Letters, raise intriguing questions about how those organics got to the surface of Ceres, and the methods used in the new study could also provide a template for interpreting data for future missions, the researchers say.

“What this paper shows is that you can get really different results depending upon the type of organic material you use to compare with and interpret the Ceres data,” said Hannah Kaplan, a postdoctoral researcher at the Southwest Research Institute who led the research while completing her Ph.D. at Brown. “That’s important not only for Ceres, but also for missions that will soon explore asteroids that may also contain organic material.”

Organic molecules are the chemical building blocks for life. Their detection on Ceres doesn’t mean life exists there or ever existed there; non-biological processes can give rise to organic molecules as well. But because life as we know it can’t exist without organic material, scientists are interested in how it’s distributed through the solar system. The presence of organic material on Ceres raises intriguing possibilities, particularly because the dwarf planet is also rich in water ice, and water is another necessary component for life.

The original discovery of organics on Ceres was made using the Visible and Infrared (VIR) Spectrometer on the Dawn spacecraft, which went into orbit around the dwarf planet in 2015. By analyzing the patterns in which sunlight interacts with the surface — looking carefully at which wavelengths are reflected and which are absorbed — scientists can get an idea of what compounds are present on Ceres. The VIR instrument picked up a signal consistent with organic molecules in the region of Ernutet Crater on Ceres’ northern hemisphere.

To get an initial idea of how abundant those compounds might be, the original research team compared the VIR data from Ceres with laboratory reflectance spectra of organic material formed on Earth. Based on that standard, the researchers concluded that between six and 10 percent of the spectral signature they detected on Ceres could be explained by organic matter.

But for this new research, Kaplan and her colleagues wanted to re-examine those data using a different standard. Instead of relying on Earth rocks to interpret the data, the team turned to an extraterrestrial source: meteorites. Some meteorites — chunks of carbonaceous chondrite that have fallen to Earth after being ejected from primitive asteroids — have been shown to contain organic material that’s slightly different from what’s commonly found on our own planet. And Kaplan’s work shows that the spectral reflectance of the extraterrestrial organics is distinct from that of terrestrial counterparts.

“What we find is that if we model the Ceres data using extraterrestrial organics, which may be a more appropriate analog than those found on Earth, then we need a lot more organic matter on Ceres to explain the strength of the spectral absorption that we see there,” Kaplan said. “We estimate that as much as 40 to 50 percent of the spectral signal we see on Ceres is explained by organics. That’s a huge difference compared to the six to 10 percent previously reported based on terrestrial organic compounds.”

If the concentration of organics on Ceres is indeed that high, it raises a host of new questions about the source of that material. There are two competing possibilities for where Ceres’ organics may have come from. They could have been produced internally on Ceres and then exposed on the surface, or they could have been delivered to the surface by an impact from an organic-rich comet or asteroid.

This new study suggests that if the organics were delivered, then the potential high concentrations of the organics would be more consistent with impact by a comet rather than an asteroid. Comets are known to have significantly higher internal abundances of organics compared with primitive asteroids, potentially similar to the 40 to 50 percent figure this study suggests for these locations on Ceres. However, the heat of an impact would likely destroy a substantial amount of a comet’s organics, so whether or not such high abundances could even be explained by a cometary impact remains unclear, the researchers say.

The alternative explanation, that the organics formed directly on Ceres, raises questions too. The detection of organics has so far been limited to small patches on Ceres’ northern hemisphere. Such high concentrations in such small areas require an explanation.

“If the organics are made on Ceres, then you likely still need a mechanism to concentrate it in these specific locations or at least to preserve it in these spots,” said Ralph Milliken, an associate professor in Brown’s Department of Earth, Environmental and Planetary Sciences and a study co-author. “It’s not clear what that mechanism might be. Ceres is clearly a fascinating object, and understanding the story and origin of organics in these spots and elsewhere on Ceres will likely require future missions that can analyze or return samples.”

For now the researchers hope this study will be helpful in informing upcoming sample return missions to near-Earth asteroids that are also thought to host water-bearing minerals and organic compounds. The Japanese spacecraft Hayabusa2 is expected to arrive at the asteroid Ryugu in several weeks, and NASA’s OSIRIS-REx mission is due to reach the asteroid Bennu in August. Kaplan is currently a science team member with the OSIRIS-REx mission.

“I think the work that went into this study, which included new laboratory measurements of important components of primitive meteorites, can provide a framework of how to better interpret data of asteroids and make links between spacecraft observations and samples in our meteorite collection,” Kaplan said. “As a new member to the OSIRIS-REx team, I’m particularly interested in how this might apply to our mission.”

The research was funded by the NASA Astrobiology Institute and the NASA Solar System Exploration Research Virtual Institute at Brown.







Contacts and sources:
Kevin Stacey
Brown University


Citation: New Constraints on the Abundance and Composition of Organic Matter on Ceres. Hannah H. Kaplan, Ralph E. Milliken, Conel M. O'D. Alexander, Geophysical Research Letters  http://dx.doi.org/10.1029/2018GL077913

New Elastic Fiber Set to Revolutionize Smart Clothes, Provide Nerves for Robots


EPFL scientists have found a fast and simple way to make super-elastic, multi-material, high-performance fibers. Their fibers have already been used as sensors on robotic fingers and in clothing. This breakthrough method opens the door to new kinds of smart textiles and medical implants.



It’s a whole new way of thinking about sensors. The tiny fibers developed at EPFL are made of elastomer and can incorporate materials like electrodes and nanocomposite polymers. The fibers can detect even the slightest pressure and strain and can withstand deformation of close to 500% before recovering their initial shape. All that makes them perfect for applications in smart clothing and prostheses, and for creating artificial nerves for robots.

The fibers were developed at EPFL’s Laboratory of Photonic Materials and Fiber Devices (FIMAP), headed by Fabien Sorin at the School of Engineering. The scientists came up with a fast and easy method for embedding different kinds of microstructures in super-elastic fibers. For instance, by adding electrodes at strategic locations, they turned the fibers into ultra-sensitive sensors. What’s more, their method can be used to produce hundreds of meters of fiber in a short amount of time. Their research has just been published in Advanced Materials.

Heat, then stretch

To make their fibers, the scientists used a thermal drawing process, which is the standard process for optical-fiber manufacturing. They started by creating a macroscopic preform with the various fiber components arranged in a carefully designed 3D pattern. They then heated the preform and stretched it out, like melted plastic, to make fibers of a few hundreds microns in diameter. And while this process stretched out the pattern of components lengthwise, it also contracted it crosswise, meaning the components’ relative positions stayed the same. The end result was a set of fibers with an extremely complicated microarchitecture and advanced properties.


Credit EPFL

Until now, thermal drawing could be used to make only rigid fibers. But Sorin and his team used it to make elastic fibers. With the help of a new criterion for selecting materials, they were able to identify some thermoplastic elastomers that have a high viscosity when heated. After the fibers are drawn, they can be stretched and deformed but they always return to their original shape.

Rigid materials like nanocomposite polymers, metals and thermoplastics can be introduced into the fibers, as well as liquid metals that can be easily deformed. “For instance, we can add three strings of electrodes at the top of the fibers and one at the bottom. Different electrodes will come into contact depending on how the pressure is applied to the fibers. This will cause the electrodes to transmit a signal, which can then be read to determine exactly what type of stress the fiber is exposed to – such as compression or shear stress, for example,” says Sorin.

Artificial nerves for robots

Working in association with Professor Dr. Oliver Brock (Robotics and Biology Laboratory, Technical University of Berlin), the scientists integrated their fibers into robotic fingers as artificial nerves. Whenever the fingers touch something, electrodes in the fibers transmit information about the robot’s tactile interaction with its environment. The research team also tested adding their fibers to large-mesh clothing to detect compression and stretching. “Our technology could be used to develop a touch keyboard that’s integrated directly into clothing, for instance” says Sorin.

The researchers see many other potential applications. Especially since the thermal drawing process can be easily tweaked for large-scale production. This is a real plus for the manufacturing sector. The textile sector has already expressed interest in the new technology, and patents have been filed.





Contacts and sources:
Laure-Anne Pessina
École polytechnique fédérale de Lausanne (EPFL)

Citation:   “Super-elastic Multi-material Electronic and Photonic Fibers and Devices via Thermal Drawing”Yunpeng Qu, Tung Nguyen-Dang, Alexis Gérald Page, Wei Yan, Tapajyoti Das Gupta, Gelu Marius Rotaru, René M. Rossi, Valentine Dominique Favrod, Nicola Bartolomei, and Fabien Sorin,, Advanced Materials

Silicon-Perovskite Solar Cells Achieve Record Efficiency of 25.2%



In Neuchâtel (Switzerland), researchers from EPFL and CSEM have combined silicon- and perovskite-based solar cells. The resulting efficiency of 25.2% is a record for this type of tandem cell. Their innovative yet simple manufacturing technique could be directly integrated into existing production lines, and efficiency could eventually rise above 30%.

In the field of photovoltaic technologies, silicon-based solar cells make up 90% of the market. In terms of cost, stability and efficiency (20-22% for a typical solar cell on the market), they are well ahead of the competition.

Silicon's pyramids covered with perovskite
Credit: © 2018 EPFL

However, after decades of research and investment, silicon-based solar cells are now close to their maximum theoretical efficiency. As a result, new concepts are required to achieve a long-term reduction in solar electricity prices and allow photovoltaic technology to become a more widely adopted way of generating power.

One solution is to place two different types of solar cells on top of each other to maximize the conversion of light rays into electrical power. These “double-junction” cells are being widely researched in the scientific community, but are expensive to make. Now research teams in Neuchâtel – from EPFL’s Photovoltaics Laboratory and the CSEM PV-center – have developed an economically competitive solution. They have integrated a perovskite cell directly on top of a standard silicon-based cell, obtaining a record efficiency of 25.2%. Their production method is promising, because it would add only a few extra steps to the current silicon-cell production process, and the cost would be reasonable. Their research has been published in Nature Materials.

Perovskite-on-silicon: a nanometric sandwich

Perovskite’s unique properties have prompted a great deal of research into its use in solar cells over the last few years. In the space of nine years, the efficiency of these cells has risen by a factor of six. Perovskite allows high conversion efficiency to be achieved at a potentially limited production cost.

In tandem cells, perovskite complements silicon: it converts blue and green light more efficiently, while silicon is better at converting red and infra-red light. “By combining the two materials, we can maximize the use of the solar spectrum and increase the amount of power generated. The calculations and work we have done show that a 30% efficiency should soon be possible,” say the study’s main authors Florent Sahli and Jérémie Werner.

However, creating an effective tandem structure by superposing the two materials is no easy task. “Silicon’s surface consists of a series of pyramids measuring around 5 microns, which trap light and prevent it from being reflected. However, the surface texture makes it hard to deposit a homogeneous film of perovskite,” explains Quentin Jeangros, who co-authored the paper.

When the perovskite is deposited in liquid form, as it usually is, it accumulates in the valleys between the pyramids while leaving the peaks uncovered, leading to short circuits.

A key layer ensuring an optimal microstructure

Scientists at EPFL and CSEM have gotten around that problem by using evaporation methods to form an inorganic base layer that fully covers the pyramids. That layer is porous, enabling it to retain the liquid organic solution that is then added using a thin-film deposition technique called spin-coating. The researchers subsequently heat the substrate to a relatively low temperature of 150°C to crystallize a homogeneous film of perovskite on top of the silicon pyramids.

“Until now, the standard approach for making a perovskite/silicon tandem cell was to level off the pyramids of the silicon cell, which decreased its optical properties and therefore its performance, before depositing the perovskite cell on top of it. It also added steps to the manufacturing process,” says Florent Sahli.

Updating existing technologies

The new type of tandem cell is highly efficient and directly compatible with monocrystalline silicon-based technologies, which benefit from long-standing industrial expertise and are already being produced profitably. “We are proposing to use equipment that is already in use, just adding a few specific stages. Manufacturers won’t be adopting a whole new solar technology, but simply updating the production lines they are already using for silicon-based cells,” explains Christophe Ballif, head of EPFL’s Photovoltaics Laboratory and CSEM’s PV-Center.

At the moment, research is continuing in order to increase efficiency further and give the perovskite film more long-term stability. Although the team has made a breakthrough, there is still work to be done before their technology can be adopted commercially.

Funding

This research has been financed by Nano-Tera.ch’s Synergy project, the Swiss Federal Office of Energy (grant SI/501072-01), the Swiss National Science Foundation through the Sinergia Episode project (CRSII5_171000) and the NRP70 Energy Turnaround PV2050 project (407040), and the European Union through the Horizon 2020 innovation and research program (CHEOPS project 653296).





Contacts and sources:
Laure-Anne Pessina
École polytechnique fédérale de Lausanne (EPFL)

Citation:  “Fully textured monolithic perovskite/silicon tandem solar cells with 25.2% power conversion efficiency,
F. Sahli, J. Werner, B. A. Kamino, M. Bräuninger, R. Monnard, B. Paviet-Salomon, L. Barraud, L. Ding, J. J. Diaz Leon, D. Sacchetto, G. Cattaneo, M. Despeisse, M. Boccard, S. Nicolay, Q. Jeangros, B. Niesen, and C. Ballif, ” Nature Materials, 2018. DOI: 10.1038/s41563-018-0115-4

Skyrmions: Exotic Quasiparticles Could Revolutionize Computing

Skyrmions: the unique physical properties of these “magic knots” might help to satisfy demand for IT power and storage using a fraction of the energy.

For most of us, any concerns about computing speed or data storage are usually to make it go faster while storing more. We hardly ever think about the enormous amounts of energy already required to power Internet servers or charge the increasing number of devices we own. “The carbon footprint of computing, IT and the Internet is becoming enormous. It’s about ten years since it became bigger than the carbon footprint of air travel,” says Christopher Marrows, professor of condensed matter physics at the University of Leeds, UK.

He is one of several collaborators on MAGicSky, a EU project that is grappling with the physics of unique “quasiparticles” called skyrmions, named after scientist Tony Skyrme who first theorised their existence in 1962. Due to their unique properties, skyrmions are smaller, and more stable and mobile than current computing and magnetic storage devices, making them a better basis for building the next generation of IT devices — plus the energy needed to power them is fractions of what we use now, from ten times less to potentially much more.

A skyrmion is a twist, or a knot, in an otherwise uniform magnetic field that creates a region in which the electrons from a group of atoms align themselves not to the magnetic poles but rather into whorls. Once arranged into this unique topology they can behave like particles and are protected from outside forces.

Graphic representation of a skyrmion.
Credit: MAGicSky consortium

“If you want to create or destroy a skyrmion, that requires you to do something quite violent to the magnetisation,” explains Marrows. “If you store data you want to be sure that when you come back and look next week, next year or in ten years’ time, that it’s still there.”

Not only are skyrmions secure, they are also tiny compared to current magnetic storage devices. “They can travel over huge distances and require very little energy to travel,” says Dr Katia Pappas, a professor at the Delft University of Technology in the Netherlands. “Skyrmions can pave the way not only to high-density storage, but also new kinds of devices with very little energy consumption.”

These new machines might one day harness the computing power of a human brain. “With a skyrmion, because it is like a little particle you can move it around in more than one dimension,” says Marrows, making their computing potential immensely greater than current methods that work in two-dimensional, binary ways. He adds that skyrmions are a promising way to be able to do something neural, natively in hardware. But before neural processing power comes to our laptops the fundamental physics of skyrmions must first be understood.

The computing’s carbon footprint is larger than that of air travel. 
Credits: Photo by Bambi Corro on Unsplash

“The stabilisation of skyrmions is something that is discussed pretty widely in the community,” says Dr Sebastian Mühlbauer, professor in the department of physics at the Technical University of Munich, Germany. For him these fundamental questions are crucial: how can you design a material which will show magnetic skyrmions? What kind of ingredients do you need? What is the minimal energy configuration? As more of this information becomes available the focus inevitably turns to applications. “There are groups looking at theory and really looking into the fundamental properties of skyrmions, but more and more people are going into the direction of applications,” says Mühlbauer.

Marrows and the MAGicSky collaborators, supported by the EU’s Future and Emerging Technologies (FET) programme, are one of the groups working to understand the fundamental physics. They have achieved skyrmions at room temperatures, a huge advance on the cryogenic temperatures once required, and Marrows specifically has increased their ability to detect skyrmions; a crucial step for reading any data stored in skyrmions.

“The equivalent in software is that we are trying to create the programming language but we are not saying what program you should write with it,” says Marrows. These advances will provide the building blocks which engineers can then incorporate into any number of devices.


Check out this short explanatory comic produced by an artist commissioned by the MAGicSky project.



Contacts and sources:
Bradley van Paridon
FETFX
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