Climate change reshaping how heat moves around globe

The Antarctic.

The Earth's atmosphere and oceans play important roles in moving heat from one part of the world to another, and new research is illuminating how those patterns are changing in the face of climate change.

"The greenhouse effect and carbon dioxide aren't the only issues to consider as the planet grows warmer -- they are just one part of the equation. The way that the atmosphere and oceans move heat around is changing, too, and this could have significant effects on temperatures around the world," said Zhengyu Liu, co-lead author of the study and professor of climate dynamics in the Department of Geography at The Ohio State University.

Liu and Chengfei He, a graduate student in Ohio State's atmospheric science program, analyzed model simulations to illustrate how heat is expected to be transferred by the oceans and atmosphere in the near future. The researchers compared the models with historical temperature data from the oceans themselves to paint a clearer picture of how climate change is shifting and will continue to shift these patterns in this century. Their study appears online today (Jan. 28, 2019) in the journal Nature Climate Change.

Without heat transfer, the world's hottest spots would be sizzling and the coolest spots would be even more frigid. Conditions in both hot and cold climates are affected by the movement of heat from the equator toward the poles in the atmosphere and oceans, He said.

As scientists look for a better understanding of all the factors contributing to climate change -- and for ways to ameliorate the problem -- these heat-transfer patterns are important to watch, He said.

This is the first study to examine current changes in heat transfer and to conclude that warming temperatures are driving increased heat transfer in the atmosphere, which is compensated by a reduced heat transfer in the ocean. Additionally, the researchers concluded that the excess oceanic heat is trapped in the Southern Ocean around the Antarctic.

"The ocean stores a lot of heat and in the last 50 years that has increased. And we can correlate that directly with increases in atmospheric carbon dioxide caused by human activity," Liu said. "Most studies like this have looked at future changes, hundreds of years from now. We examined the near-term differences of a warming climate."

For now, that heat is not re-entering the atmosphere, but at some point it may. If that were to happen, changes in heat transfer could contribute to significant shifts in normal temperatures worldwide, he said.

"For instance, if we didn't have heat transfer, Ohio would be 20 or 30 degrees colder than we are right now," Liu said. "Therefore, it is important to predict how the heat transfer will be changed in the future."

Read more at Science Daily

'Metallic wood' has the strength of titanium and the density of water

A microscopic sample of the researchers' "metallic wood." Its porous structure is responsible for its high strength-to-weight ratio, and makes it more akin to natural materials, like wood.

High-performance golf clubs and airplane wings are made out of titanium, which is as strong as steel but about twice as light. These properties depend on the way a metal's atoms are stacked, but random defects that arise in the manufacturing process mean that these materials are only a fraction as strong as they could theoretically be. An architect, working on the scale of individual atoms, could design and build new materials that have even better strength-to-weight ratios.

In a new study published in Nature Scientific Reports, researchers at the University of Pennsylvania's School of Engineering and Applied Science, the University of Illinois at Urbana-Champaign, and the University of Cambridge have done just that. They have built a sheet of nickel with nanoscale pores that make it as strong as titanium but four to five times lighter.

The empty space of the pores, and the self-assembly process in which they're made, make the porous metal akin to a natural material, such as wood.

And just as the porosity of wood grain serves the biological function of transporting energy, the empty space in the researchers' "metallic wood" could be infused with other materials. Infusing the scaffolding with anode and cathode materials would enable this metallic wood to serve double duty: a plane wing or prosthetic leg that's also a battery.

The study was led by James Pikul, Assistant Professor in the Department of Mechanical Engineering and Applied Mechanics at Penn Engineering. Bill King and Paul Braun at the University of Illinois at Urbana-Champaign, along with Vikram Deshpande at the University of Cambridge, contributed to the study.

Even the best natural metals have defects in their atomic arrangement that limit their strength. A block of titanium where every atom was perfectly aligned with its neighbors would be ten times stronger than what can currently be produced. Materials researchers have been trying to exploit this phenomenon by taking an architectural approach, designing structures with the geometric control necessary to unlock the mechanical properties that arise at the nanoscale, where defects have reduced impact.

Pikul and his colleagues owe their success to taking a cue from the natural world.

"The reason we call it metallic wood is not just its density, which is about that of wood, but its cellular nature," Pikul says. "Cellular materials are porous; if you look at wood grain, that's what you're seeing? -- ?parts that are thick and dense and made to hold the structure, and parts that are porous and made to support biological functions, like transport to and from cells."

"Our structure is similar," he says. "We have areas that are thick and dense with strong metal struts, and areas that are porous with air gaps. We're just operating at the length scales where the strength of struts approaches the theoretical maximum."

The struts in the researchers' metallic wood are around 10 nanometers wide, or about 100 nickel atoms across. Other approaches involve using 3D-printing-like techniques to make nanoscale scaffoldings with hundred-nanometer precision, but the slow and painstaking process is hard to scale to useful sizes.

"We've known that going smaller gets you stronger for some time," Pikul says, "but people haven't been able to make these structures with strong materials that are big enough that you'd be able to do something useful. Most examples made from strong materials have been about the size of a small flea, but with our approach, we can make metallic wood samples that are 400 times larger."

Pikul's method starts with tiny plastic spheres, a few hundred nanometers in diameter, suspended in water. When the water is slowly evaporated, the spheres settle and stack like cannonballs, providing an orderly, crystalline framework. Using electroplating, the same technique that adds a thin layer of chrome to a hubcap, the researchers then infiltrate the plastic spheres with nickel. Once the nickel is in place, the plastic spheres are dissolved with a solvent, leaving an open network of metallic struts.

"We've made foils of this metallic wood that are on the order of a square centimeter, or about the size of a playing die side," Pikul says. "To give you a sense of scale, there are about 1 billion nickel struts in a piece that size."

Because roughly 70 percent of the resulting material is empty space, this nickel-based metallic wood's density is extremely low in relation to its strength. With a density on par with water's, a brick of the material would float.

Replicating this production process at commercially relevant sizes is the team's next challenge. Unlike titanium, none of the materials involved are particularly rare or expensive on their own, but the infrastructure necessary for working with them on the nanoscale is currently limited. Once that infrastructure is developed, economies of scale should make producing meaningful quantities of metallic wood faster and less expensive.

Once the researchers can produce samples of their metallic wood in larger sizes, they can begin subjecting it to more macroscale tests. A better understanding of its tensile properties, for example, is critical.

"We don't know, for example, whether our metallic wood would dent like metal or shatter like glass." Pikul says. "Just like the random defects in titanium limit its overall strength, we need to get a better understand of how the defects in the struts of metallic wood influence its overall properties."

In the meantime, Pikul and his colleagues are exploring the ways other materials can be integrated into the pores in their metallic wood's scaffolding.

Read more at Science Daily

Milky Way's neighbors pick up the pace

Taken with the European Southern Observatory's Gaia Satellite, the maps show the relative abundance of heavy elements (elements heavier than helium) in the stars. Yellow indicates fewer heavy elements and purple indicates more heavy elements.

After slowly forming stars for the first few billion years of their lives, the Magellanic Clouds, near neighbors of our own Milky Way galaxy, have upped their game and are now forming new stars at a fast clip. This new insight into the history of the Clouds comes from the first detailed chemical maps made of galaxies beyond the Milky Way.

Named for explorer Ferdinand Magellan, who led the first European expedition to circumnavigate the globe, the Large and Small Magellanic Clouds are the Milky Way's nearest galactic neighbors -- companion galaxies that will someday merge with our galaxy. The two galaxies are visible only from the Southern Hemisphere, where they look like bright, wispy clouds.

A Map to Stellar History

Although humans have gazed at the Clouds for millennia, this is the first time astronomers have made a detailed map of the chemical compositions of the stars within them. The project, carried out by the Sloan Digital Sky Survey (SDSS), was led by NOAO astronomer David Nidever, who is also a research professor of physics at Montana State University.

"We mapped the positions, movements, and chemical make-up of thousands of stars in the Magellanic Clouds," said Nidever. "Reading these maps helps us reconstruct the history of when these galaxies formed their stars."

The maps are the first major discovery to come out of the new southern operations of SDSS's Apache Point Observatory Galaxy Evolution Experiment 2 (APOGEE-2) survey, which is being carried out on the Irénée du Pont Telescope at Las Campanas Observatory in Chile.

Making Maps from Stellar Spectra

To make the maps, the SDSS team collected spectra of as many stars as possible. Spectra, which spread out the light from a star in the form of a rainbow, encode the motions of stars, their temperature, the chemical elements they contain, and their stage in the stellar life cycle.

By measuring the chemical make-up of a galaxy's stars, astronomers are able to infer their "star formation history," a rough record of the rate at which stars formed over time. The reconstruction is possible because of the difference in the lifetimes of stars of different masses and the role more massive stars play in enriching galaxies with heavy elements.

As stars age, stars more massive than the Sun evolve and explode as supernovae, ejecting heavy elements out into the galaxy, while less massive stars live on. The ejected elements mix with the existing gas, enriching it. New generations of stars form from the enriched gas and inherit that chemical make-up. The process repeats, with the longer-lived lower mass stars surviving to record the enrichment history of the galaxy. By mapping the abundances of these stars, astronomers can "read" the star formation record of the galaxy.

Slow Start Followed by a Bang

The results show that the star formation history of the Large and Small Magellanic Clouds is completely different from that of our galaxy. "In the Milky Way, star formation began like gangbusters and later declined," explained team member Sten Hasselquist from the University of Utah. "In contrast, in the Magellanic Clouds, stars formed extremely slowly at early times, at a rate only 1/50th of the star formation rate in the Milky Way, but that rate has skyrocketed in the last 2 billion years."

Nidever thinks that the dramatic increase in the star formation rate is due to the interaction of the Magellanic Clouds with one another as they tumble toward the Milky Way. "The Clouds began their lives calmly in a relatively isolated part of the Universe, where there was no reason to form stars," said Nidever. "But in the last few billion years, the close interactions that the Clouds have had with each other and with the Milky Way is causing the gas in the Clouds to transform into stars."

Read more at Science Daily

The helix, of DNA fame, may have arisen with startling ease

A proto-nucleobase next to a nucleobase. Hard to tell the difference.

Trying to explain how DNA and RNA evolved to form such neat spirals has been a notorious enigma in science. But a new study suggests the rotation may have occurred with ease billions of years ago when RNA's chemical ancestors casually spun into spiraled strands.

In the lab, researchers at the Georgia Institute of Technology were surprised to see them do it under conditions thought to be common on Earth just before first life evolved: in plain water, with no catalysts, and at room temperature.

The neat spiraling also elegantly integrated another compound which today forms the backbone of RNA and DNA. The resulting structure had features that strongly resembled RNA.

Pivotal twists

The study has come a step closer to answering a chicken-egg question about the evolutionary path that led to RNA (from which DNA later evolved): Did the spiral come first, and did this structure influence which molecular components made it later into RNA because they fit well into the spiral?

"The spiraling could have had a reinforcing effect. It could have facilitated the molecules getting connected together that have the same chirality (curve) to connect into a common backbone that is compatible with the helical twist," said the study's principal investigator Nicholas Hud, a Regents Professor in Georgia Tech's School of Chemistry and Biochemistry.

The researchers published the new study in the journal Angewandte Chemie in December 2018. The research was funded by the National Science Foundation and the NASA Astrobiology Program under the Center for Chemical Evolution. The center is headquartered at Georgia Tech, and Hud is its principal investigator.

The study's resulting polymers were not RNA but could be have been an important intermediate step in the early evolution of RNA. For building blocks, the researchers used base molecules referred to as "proto-nucleobases," highly suspected to be precursors of nucleobases, main components that transport genetic code in today's RNA.

Nucleobase paradox

The study had to work around a paradox in chemical evolution:

Making RNA or DNA using their actual nucleobases in the lab without the aid of the enzymes of living cells that usually do this job is more than a herculean task. Thus, although RNA and DNA are ubiquitous on Earth now, their evolution on pre-life Earth would appear to have been an anomaly requiring erratic convergences of extreme conditions.

By contrast, the Georgia Tech researchers' model of chemical evolution holds that precursor nucleobases self-assembled easily to into ancestral prototypes -- that were polymer-like and referred to as assemblies -- which later evolved into RNA.

"We would call these 'proto-nucleobases' or 'ancestral nucleobases,'" Hud said. "For our overall model of chemical evolution, we're saying that these proto-nucleobases, which self-assemble into these long strands, could have been part of a very early stage before modern nucleobases were incorporated."

One main suspected proto-nucleobase in this experiment -- and in previous experiments on the possible the evolution of RNA -- was triaminopyrimidine (TAP). Cyanuric acid (CA) was another. The researchers highly suspect TAP and CA were parts of a proto-RNA.

The chemical bonds that hold together assemblies of the two suspected proto-nucleobases were surprisingly strong but non-covalent, which is akin to connecting two magnets. In RNA the main bonds holding together modern nucleobases are covalent bonds, akin to welding, and enzymes make those bonds in cells today.

Helical biases

A helix can spiral two ways, left-handed or right-handed. In chemistry, a molecule can also be handed, or chiral, making for "L" or "D" forms of the molecule.

Incidentally, the building blocks of today's RNA and DNA are all the D form, which make a right-handed helix. Why they evolved like this is still a mystery.

Batches of TAP and CA the researchers started out with produced roughly equal amounts of right and left-handed helices, but something stood out: Whole regions of a batch were biased in one direction and were separate from other regions that spiraled mostly the other way.

"The propensity for the molecules to choose one helical direction was so strong that large regions of the batches were made up predominantly of assemblies that were unidirectionally twisted," Hud said.

This was surprising because the individual molecules of TAP and CA had no chirality of their own, neither L nor D. Still, the twists had a preferred direction.

'World record'

The researchers added two more experiments to test how strongly their RNA-like assemblies preferred making one-handed helices.

First, they introduced a smidgeon of compounds similar to TAP and CA, but which had L or D chirality, to nudge the spiraling direction. The whole batch conformed to the chirality of the respective additive, resulting in assemblies twisting in a unified direction as helices do in RNA and DNA today.

"It was the new world record for the smallest amount of a chiral dopant (additive) that would flip a whole solution," said Suneesh Karunakaran, the study's first author and a graduate researcher in Hud's lab. "This demonstrated how easy it would be in nature to get abundant amounts of unified helices."

Second, they put the sugar compound ribose-5-phosphate together with TAP to more closely emulate the current building blocks of RNA. The ribose fell into place, and the resulting assembly spiraled in a direction dictated by the ribose chirality.

"This molecule easily formed an RNA-like assembly that was surprisingly stable, even though the pieces were only held together by non-covalent bonds," Karunakaran said.

Evolution revolution

The study's results under such simple conditions represent a leap forward in experimental evidence for how the helical twist of biomolecules could have already been in place long before life emerged.

The research also expands a growing body of evidence supporting an unconventional hypothesis by the Center for Chemical Evolution, which dispenses with the need for a narrative that rare cataclysms and unlikely ingredients were necessary to produce life's early building blocks.

Instead, most biomolecules likely arose in several gradual steps, on quiet, rain-swept dirt flats or lakeshore rocks lapped by waves. Precursor molecules with the right reactivity enabled those steps readily and produced abundant materials for further evolutionary steps.

Basement engineer

In the lab, helix self-assemblage was so productive that it outstripped a detection device's capacity to examine the output. Regions a square millimeter or more in size were packed with unidirectionally spiraled polymer-like assemblies.

"To look at them I had to make adjustments to the equipment," said Karunakaran. "I punched holes in a foil and put it in front of the beam of our spectropolarimeter."

Read more at Science Daily

Fault lines are no barrier to safe storage of CO2 below ground

Carbon dioxide emissions can be securely stored in underground rocks, with minimal possibility of the gas escaping from fault lines back into the atmosphere, research by the University of Edinburgh has shown.

Carbon dioxide emissions can be captured and securely stored in underground rocks, even if geological faults are present, research has confirmed.

There is minimal possibility of the gas escaping from fault lines back into the atmosphere, the study has shown.

The findings are further evidence that an emerging technology known as Carbon Capture and Storage (CCS), in which CO2 gas emissions from industry are collected and transported for underground storage, is reliable.

Such an approach can reduce emissions of CO2 and help to limit the impact of climate change. If widely adopted, CCS could help meet targets set by the 2015 UN Paris Agreement, which seeks to limit climate warming to below 2C compared with pre-industrial levels.

The latest findings, from tests on a naturally occurring CO2 reservoir, may address public concerns over the proposed long-term storage of carbon dioxide in depleted gas and oil fields.

Scientists from the Universities of Edinburgh, Freiburg, Glasgow and Heidelberg studied a natural CO2 repository in Arizona, US, where gas migrates through geological faults to the surface.

Researchers used chemical analysis to calculate the amount of gas that had escaped the underground store over almost half a million years.

They found that a very small amount of carbon dioxide escaped the site each year, well within the safe levels needed for effective storage.

The study, published in Scientific Reports, was supported by the European Union and Natural Environment Research Council.

Dr Stuart Gilfillan, of the University of Edinburgh's School of GeoSciences, who jointly led the study, said: "This shows that even sites with geological faults are robust, effective stores for CO2. This find significantly increases the number of sites around the world that may be suited to storage of this harmful greenhouse gas."

Dr Johannes Miocic, of the University of Freiburg, who jointly led the study, said: "The safety of carbon dioxide storage is crucial for successful widespread implementation of much-needed carbon capture and storage technology. Our research shows that even imperfect sites can be secure stores for hundreds of thousands of years."

From Science Daily

Rocking motion improves sleep and memory, studies in mice and people show

Asleep in a hammock.

Anyone who has ever put a small child to bed or drifted off in a gently swaying hammock will know that a rocking motion makes getting to sleep seem easier. Now, two new studies reported in Current Biology on January 24, one conducted in young adults and the other in mice, add to evidence for the broad benefits of a rocking motion during sleep. In fact, the studies in people show that rocking not only leads to better sleep, but it also boosts memory consolidation during sleep.

"Having a good night's sleep means falling asleep rapidly and then staying asleep during the whole night," says Laurence Bayer of the University of Geneva, Switzerland. "Our volunteers -- even if they were all good sleepers -- fell asleep more rapidly when rocked and had longer periods of deeper sleep associated with fewer arousals during the night. We thus show that rocking is good for sleep."

Bayer and their colleagues had earlier shown that continuous rocking during a 45-minute nap helped people to fall asleep faster and sleep more soundly. In the new study, led by Laurence Bayer and Sophie Schwartz, University of Geneva, Switzerland, they wanted to explore the effects of rocking on sleep and its associated brain waves throughout the night.

The researchers enlisted 18 healthy young adults to undergo sleep monitoring in the lab. The first night was intended to get them used to sleeping there. They then stayed two more nights -- one sleeping on a gently rocking bed and the other sleeping on an identical bed that wasn't moving.

The data showed that participants fell asleep faster while rocking. Once asleep, they also spent more time in non-rapid eye movement sleep, slept more deeply, and woke up less.

Next, the researchers wanted to know how that better sleep influenced memory. To assess memory consolidation, participants studied word pairs. The researchers then measured their accuracy in recalling those paired words in an evening session compared to the next morning when they woke up. They found that people did better on the morning test when they were rocked during sleep.

Further studies showed that rocking affects brain oscillations during sleep. They saw that the rocking motion caused an entrainment of specific brain oscillations of non-rapid eye movement sleep (slow oscillations and spindles). As a result, the continuous rocking motion helped to synchronize neural activity in the thalamo-cortical networks of the brain, which play an important role in both sleep and memory consolidation.

The second study in mice by Konstantinos Kompotis and colleagues is the first to explore whether rocking promotes sleep in other species. And, indeed, it did. The researchers, led by Paul Franken, University of Lausanne, Switzerland, used commercial reciprocating shakers to rock the cages of mice as they slept.

While the best rocking frequency for mice was found to be four times faster than in people, the researchers' studies show that rocking reduced the time it took to fall asleep and increased sleep time in mice as it does in humans. However, the mice did not show evidence of sleeping more deeply.

Researchers had suspected that the effects of rocking on sleep were tied to rhythmic stimulation of the vestibular system, the sensory system that contributes to the sense of balance and spatial orientation. To explore this notion in the mouse, the researchers studied animals whose vestibular systems were disrupted by non-functioning otolithic organs, found in their ears. Their studies showed that mice lacking working otolithic organs experienced none of the beneficial effects of rocking during sleep.

Taken together, the two studies "provide new insights into the neurophysiological mechanisms underlying the effects of rocking stimulation on sleep," Bayer and Perrault write. The findings may be relevant for the development of new approaches for treating patients with insomnia and mood disorders, as well as older people, who frequently suffer from poor sleep and memory impairments.

The researchers say it will be essential in future work to explore the precise deeper brain structures involved in the effects of rocking on sleep.

Read more at Science Daily

A reptile platypus from the early Triassic

Complete fossil and line drawing of Eretmorhipis carrolldongi. Related to the dolphin-like ichthyosaurs, Eretmorhipis evolved in a world devastated by the mass extinction event at the end of the Permian era.

No animal alive today looks quite like a duckbilled platypus, but about 250 million years ago something very similar swam the shallow seas in what is now China, finding prey by touch with a cartilaginous bill. The newly discovered marine reptile Eretmorhipis carrolldongi from the lower Triassic period is described in the journal Scientific Reports Jan. 24.

Apart from its platypus-like bill, Eretmorhipis was about 70 centimeters long with a long rigid body, small head and tiny eyes, and four flippers for swimming and steering. Bony plates ran down the animal's back.

Eretmorhipis was previously known only from partial fossils without a head, said Professor Ryosuke Motani, a paleontologist at the University of California, Davis Department of Earth and Planetary Sciences and coauthor on the paper.

"This is a very strange animal," Motani said. "When I started thinking about the biology I was really puzzled."

The two new fossils show the animal's skull had bones that would have supported a bill of cartilage. Like the modern platypus, there is a large hole in the bones in the middle of the bill. In the platypus, the bill is filled with receptors that allow it to hunt by touch in muddy streams.

In the early Triassic, the area was covered by a shallow sea, about a meter deep, over a carbonate platform extending for hundreds of miles. Eretmorhipis fossils were found at what were deeper holes, or lagoons, in the platform. There are no fossils to show what Eretmorhipis ate, but it likely fed on shrimp, worms and other small invertebrates, Motani said.

Its long, bony body means that Eretmorhipis was probably a poor swimmer, Motani said.

"It wouldn't survive in the modern world, but it didn't have any rivals at the time," he said.

Related to the dolphin-like ichthyosaurs, Eretmorhipis evolved in a world devastated by the mass extinction event at the end of the Permian era. The fossil provides more evidence of rapid evolution occurring during the early Triassic, Motani said.

Co-authors on the study are Long Cheng and Chun-bo Yan, Wuhan Centre of China Geological Survey, Wuhan; Da-yong Jiang, Peking University; Andrea Tintori, Università degli Studi di Milano, Italy; and Olivier Rieppel, The Field Museum, Chicago. The work was supported by grants from the China Geological Survey, the National Natural Science Foundation of China and the Ministry of Science and Technology.

From Science Daily

Neanderthal hunting spears could kill at a distance

This is a photo of the spear fragment from Clacton-on-Sea, England dating from 400,000 years ago.

Neanderthals have been imagined as the inferior cousins of modern humans, but a new study by archaeologists at UCL reveals for the first time that they produced weaponry advanced enough to kill at a distance.

The study, published in Scientific Reports, examined the performance of replicas of the 300,000 year old Schöningen spears -- the oldest weapons reported in archaeological records -- to identify whether javelin throwers could use them to hit a target at distance.

Dr Annemieke Milks (UCL Institute of Archaeology), who led the study, said: "This study is important because it adds to a growing body of evidence that Neanderthals were technologically savvy and had the ability to hunt big game through a variety of hunting strategies, not just risky close encounters. It contributes to revised views of Neanderthals as our clever and capable cousins."

The research shows that the wooden spears would have enabled Neanderthals to use them as weapons and kill at distance. It is a significant finding given that previous studies considered Neanderthals could only hunt and kill their prey at close range.

The Schöningen spears are a set of ten wooden throwing spears from the Palaeolithic Age that were excavated between 1994 and 1999 in an open-cast lignite mine in Schöningen, Germany, together with approximately 16,000 animal bones.

The Schöningen spears represent the oldest completely preserved hunting weapons of prehistoric Europe so far discovered. Besides Schöningen, a spear fragment from Clacton-on-Sea, England dating from 400,000 years ago can be found at the Natural History Museum, London.

The study was conducted with six javelin athletes who were recruited to test whether the spears could be used to hit a target at a distance. Javelin athletes were chosen for the study because they had the skill to throw at high velocity, matching the capability of a Neanderthal hunter.

Owen O'Donnell, an alumnus of UCL Institute of Archaeology, made the spear replicas by hand using metal tools. They were crafted from Norwegian spruce trees grown in Kent, UK. The surface was manipulated at the final stage with stone tools, creating a surface that accurately replicated that of a Pleistocene wooden spear. Two replicas were used, weighing 760g and 800g, which conform to ethnographic records of wooden spears.

The javelin athletes demonstrated that the target could be hit at up to 20 metres, and with significant impact which would translate into a kill against prey. This is double the distance that scientists previously thought the spears could be thrown, demonstrating that Neanderthals had the technological capabilities to hunt at a distance as well as at close range.

The weight of the Schöningen spears previously led scientists to believe that they would struggle to travel at significant speed. However, the study shows that the balance of weight and the speed at which the athletes could throw them produces enough kinetic energy to hit and kill a target.

Dr Matt Pope (UCL Institute of Archaeology), co-author on the paper, said: "The emergence of weaponry -- technology designed to kill -- is a critical but poorly established threshold in human evolution.

"We have forever relied on tools and have extended our capabilities through technical innovation. Understanding when we first developed the capabilities to kill at distance is therefore a dark, but important moment in our story."

Read more at Science Daily

Rapidly receding glaciers on Baffin Island reveal long-covered Arctic landscapes

An aerial view of the Baffin Islands in Canada.

Glacial retreat in the Canadian Arctic has uncovered landscapes that haven't been ice-free in more than 40,000 years and the region may be experiencing its warmest century in 115,000 years, new University of Colorado Boulder research finds.

The study, published today in the journal Nature Communications, uses radiocarbon dating to determine the ages of plants collected at the edges of 30 ice caps on Baffin Island, west of Greenland. The island has experienced significant summertime warming in recent decades.

"The Arctic is currently warming two to three times faster than the rest of the globe, so naturally, glaciers and ice caps are going to react faster," said Simon Pendleton, lead author and a doctoral researcher in CU Boulder's Institute of Arctic and Alpine Research (INSTAAR).

Baffin is the world's fifth largest island, dominated by deeply incised fjords separated by high-elevation, low-relief plateaus. The thin, cold plateau ice acts as a kind of natural cold storage, preserving ancient moss and lichens in their original growth position for millennia.

"We travel to the retreating ice margins, sample newly exposed plants preserved on these ancient landscapes and carbon date the plants to get a sense of when the ice last advanced over that location," Pendleton said. "Because dead plants are efficiently removed from the landscape, the radiocarbon age of rooted plants define the last time summers were as warm, on average, as those of the past century"

In August, the researchers collected 48 plant samples from 30 different Baffin ice caps, encompassing a range of elevations and exposures. They also sampled quartz from each site in order to further establish the age and ice cover history of the landscape.

Once the samples were processed and radiocarbon dated back in labs at the Institute of Arctic and Alpine Research (INSTAAR) at CU Boulder and the University of California Irvine, the researchers found that these ancient plants at all 30 ice caps have likely been continuously covered by ice for at least the past 40,000 years.

"Unlike biology, which has spent the past three billion years developing schemes to avoid being impacted by climate change, glaciers have no strategy for survival," said Gifford Miller, senior author of the research and a professor of geological sciences at CU Boulder. "They're well behaved, responding directly to summer temperature. If summers warm, they immediately recede; if summers cool, they advance. This makes them one of the most reliable proxies for changes in summer temperature."

When compared against temperature data reconstructed from Baffin and Greenland ice cores, the findings suggest that modern temperatures represent the warmest century for the region in 115,000 years and that Baffin could be completely ice-free within the next few centuries.

"You'd normally expect to see different plant ages in different topographical conditions," Pendleton said. "A high elevation location might hold onto its ice longer, for example. But the magnitude of warming is so high that everything is melting everywhere now."

"We haven't seen anything as pronounced as this before," Pendleton said.

Read more at Science Daily

Static electricity could charge our electronics

These images show how the surfaces of magnesia (top block) and barium titanate (bottom block) respond when they come into contact. The resulting lattice deformations in each object contributes to the driving force behind the electric charge transfer during friction.

Unhappy with the life of your smartphone battery?

Thought so.

Help could be on the way from one of the most common, yet poorly understand, forms of power generation: static electricity.

"Nearly everyone has zapped their finger on a doorknob or seen child's hair stick to a balloon. To incorporate this energy into our electronics, we must better understand the driving forces behind it," says James Chen, PhD, assistant professor in the Department of Mechanical and Aerospace Engineering in the School of Engineering and Applied Sciences at the University at Buffalo.

Chen is a co-author of a study in the December issue of the Journal of Electrostatics that suggests the cause of this hair-raising phenomenon is tiny structural changes that occur at the surface of materials when they come into contact with each other.

The finding could ultimately help technology companies create more sustainable and longer-lasting power sources for small electronic devices.

Supported by a $400,000 National Science Foundation grant, Chen and Zayd Leseman, PhD, associate professor of mechanical and nuclear engineering at Kansas State University, are conducting research on the triboelectric effect, a phenomenon wherein one material becomes electrically charged after it contacts a different material through friction.

The triboelectric effect has been known since ancient times, but the tools for understanding and applying it have only become available recently due to the advent of nanotechnology.

"The idea our study presents directly answers this ancient mystery, and it has the potential to unify the existing theory. The numerical results are consistent with the published experimental observations," says Chen.

The research Chen and Leseman conduct is a mix of disciplines, including contact mechanics, solid mechanics, materials science, electrical engineering and manufacturing. With computer models and physical experiments, they are engineering triboelectric nanogenerators (TENGs), which are capable of controlling and harvesting static electricity.

"The friction between your fingers and your smartphone screen. The friction between your wrist and smartwatch. Even the friction between your shoe and the ground. These are great potential sources of energy that we can to tap into," Chen says. "Ultimately, this research can increase our economic security and help society by reducing our need for conventional sources of power."

Read more at Science Daily