Feb 18, 2017

Big improvement to brain-computer interface

When people suffer spinal cord injuries and lose mobility in their limbs, it's a neural signal processing problem. The brain can still send clear electrical impulses and the limbs can still receive them, but the signal gets lost in the damaged spinal cord.

The Center for Sensorimotor Neural Engineering (CSNE) -- a collaboration of San Diego State University with the University of Washington and the Massachusetts Institute of Technology -- is working on an implantable brain chip that can record neural electrical signals and transmit them to receivers in the limb, bypassing the damage and restoring movement. Recently, these researchers described in a study published in the journal Nature Scientific Reports a critical improvement to the technology that could make it more durable, last longer in the body and transmit clearer, stronger signals.

The technology, known as a brain-computer interface, records and transmits signals through electrodes, which are tiny pieces of material that read signals from brain chemicals known as neurotransmitters. By recording brain signals at the moment a person intends to make some movement, the interface learns the relevant electrical signal pattern and can transmit that pattern to the limb's nerves, or even to a prosthetic limb, restoring mobility and motor function.

The current state-of-the-art material for electrodes in these devices is thin-film platinum. The problem is that these electrodes can fracture and fall apart over time, said one of the study's lead investigators, Sam Kassegne, deputy director for the CSNE at SDSU and a professor in the mechanical engineering department.


"Glassy carbon is much more promising for reading signals directly from neurotransmitters," Kassegne said. "You get about twice as much signal-to-noise. It's a much clearer signal and easier to interpret."

The glassy carbon electrodes are fabricated here on campus. The process involves patterning a liquid polymer into the correct shape, then heating it to 1000 degrees Celsius, causing it become glassy and electrically conductive. Once the electrodes are cooked and cooled, they are incorporated into chips that read and transmit signals from the brain and to the nerves.

Researchers in Kassegne's lab are using these new and improved brain-computer interfaces to record neural signals both along the brain's cortical surface and from inside the brain at the same time. "If you record from deeper in the brain, you can record from single neurons," explained Elisa Castagnola, one of the researchers. "On the surface, you can record from clusters. This combination gives you a better understanding of the complex nature of brain signaling."

A doctoral graduate student in Kassegne's lab, Mieko Hirabayashi, is exploring a slightly different application of this technology. She's working with rats to find out whether precisely calibrated electrical stimulation can cause new neural growth within the spinal cord. The hope is that this stimulation could encourage new neural cells to grow and replace damaged spinal cord tissue in humans. The new glassy carbon electrodes will allow her to stimulate, read the electrical signals of and detect the presence of neurotransmitters in the spinal cord better than ever before.

Read more at Science Daily

Liquid Metal Circuits and Atomic Microchips Could Be the Future of Electronics

In recent years, scientists have been very interested indeed about the concept of two-dimensional materials, sometimes called 2D materials or single-layer materials. As the name suggests, these are structures so thin — down to a single layer of atoms — that they've functionally abandoned the third dimension altogether.

The single-layer variant of carbon known as graphene is the rock star of this particular class of materials, which chemical engineers hope will power the next generation of super-small semiconductors. The tricky part is getting these atomically skinny two-dimensional materials to "plug in" to traditional three-dimensional manufacturing systems.

News out of Australia this week is pointing things in an interesting direction by incorporating liquid metals and a kind of nanoscale version of rust.

Research published today in the journal Nature Communications describes a new technique for creating integrated circuits that are just a few atoms in thickness. The process could potentially allow microchip companies to manufacture circuit wafers as thin as 1.5 nanometers. How skinny is that? Pretty skinny. Consider that a standard sheet of paper is about 100,000 nanometers thick.

"This is a truly revolutionary development," said lead researcher Kourosh Kalantar-zadeh, in an email exchange from his offices at the Royal Melbourne Institute of Technology in Australia. "Our idea will be one of the first steps toward translation of the 2D world into real electronic technologies."

The specifics get complicated indeed — quantum physics are involved — but the essential gist is this: The new technique leverages certain atomic properties of metals with a relatively low melting point — gallium and indium, if you're keeping score at home. These metals naturally form a thin layer of oxide on their surface when in an oxygenated environment. This oxide, a kind of nanoscale variation of rust, can then be transferred onto a pre-treated electronic wafer, creating individual transistors.

"We use nature itself to form atomically thin, self-limiting oxides with no extra manipulation," Kalantar-zadeh said. "It is the force of nature that produces them perfectly and with no ripples and steps. Because the technology comes from the simplest observation in nature, it will impact technologies very rapidly as it is simple, understandable, and easy to implement."

And just in time, too, according to Kalantar-zadeh, who believes the process represents the next big advance for electronics.

"The fundamental technology of car engines has not progressed since 1920 and now the same is happening to electronics," he said in a statement accompanying the research publication. "Mobile phones and computers are no more powerful than five years ago.

"That is why this new 2D printing technique is so important — creating many layers of incredibly thin electronic chips on the same surface dramatically increases processing power and reduces costs. It will allow for the next revolution in electronics."

Read more at Discovery News

Feb 17, 2017

New method uses heat flow to levitate variety of objects

UChicago researchers achieved levitation of macroscopic objects between warm and cold plates in a vacuum chamber.
Although scientists have been able to levitate specific types of material, a pair of UChicago undergraduate physics students helped take the science to a new level.

Third-year Frankie Fung and fourth-year Mykhaylo Usatyuk led a team of UChicago researchers who demonstrated how to levitate a variety of objects -- ceramic and polyethylene spheres, glass bubbles, ice particles, lint strands and thistle seeds -- between a warm plate and a cold plate in a vacuum chamber.

"They made lots of intriguing observations that blew my mind," said Cheng Chin, professor of physics, whose ultracold lab in the Gordon Center for Integrative Science was home to the experiments.

Usatyuk and Fung

In their work, researchers achieved a number of levitation breakthroughs, in terms of duration, orientation and method: The levitation lasted for more than an hour, as opposed to a few minutes; stability was achieved radially and vertically, as opposed to just vertically; and it used a temperature gradient rather than light or a magnetic field. Their findings appeared Jan. 20 in Applied Physics Letters.

"Magnetic levitation only works on magnetic particles, and optical levitation only works on objects that can be polarized by light, but with our first-of-its-kind method, we demonstrate a method to levitate generic objects," said Chin.

In the experiment, the bottom copper plate was kept at room temperature while a stainless steel cylinder filled with liquid nitrogen served as the top plate. The upward flow of heat from the warm to the cold plate kept the particles suspended indefinitely.

"The large temperature gradient leads to a force that balances gravity and results in stable levitation," said Fung, the study's lead author. "We managed to quantify the thermophoretic force and found reasonable agreement with what is predicted by theory. This will allow us to explore the possibilities of levitating different types of objects." (Thermophoresis refers to the movement of particles by means of a temperature gradient.)

"Our increased understanding of the thermophoretic force will help us investigate the interactions and binding affinities between the particles we observed," said Usatyuk, a study co-author. "We are excited about the future research directions we can follow with our system."

The key to obtaining high levitation stability is the geometrical design of the two plates. A proper ratio of their sizes and vertical spacing allows the warm air to flow around and efficiently capture the levitated objects when they drift away from the center. Another sensitivity factor is that the thermal gradient needs to be pointing upward -- even a misalignment of one degree will greatly reduce the levitation stability.

"Only within a narrow range of pressure, temperature gradient and plate geometric factors can we reach stable and long levitation," Chin said. "Different particles also require fine adjustment of the parameters."

The apparatus offers a new ground-based platform to investigate the dynamics of astrophysical, chemical and biological systems in a microgravity environment, according to the researchers.

Levitation of macroscopic particles in a vacuum is of particular interest due to its wide applications in space, atmospheric and astro-chemical research. And thermophoresis has been utilized in aerosol thermal precipitators, nuclear reactor safety and the manufacturing of optical fibers through vacuum deposition processes, which apply progressive layers of atoms or molecules during fabrication.

The new method is significant because it offers a new approach to manipulating small objects without contacting or contaminating them, said Thomas Witten, the Homer J. Livingston Professor Emeritus of Physics. "It offers new avenues for mass assembly of tiny parts for micro-electro-mechanical systems, for example, and to measure small forces within such systems.

"Also, it forces us to re-examine how 'driven gases,' such as gases driven by heat flow, can differ from ordinary gases," he added. "Driven gases hold promise to create new forms of interaction between suspended particles."

Read more at Science Daily

Scarcity of resources led to violence in prehistoric central California

Joshua Tree, California (stock image). This study going back more than 1,000 years, found that California had the highest population density in all of North America, with lots of small groups living in close proximity.
A longtime Cal Poly Pomona anthropology professor who studies violence among prehistoric people in California has been published in a prestigious journal.

Professor Mark Allen's study, titled "Resource scarcity drives lethal aggression among prehistoric hunter-gathers in central California," was published in the Proceedings of the National Academy of Sciences of the United States of America, one of the top journals highlighting the general sciences. Allen teamed up with professors at U.C. Davis, the University of Utah, Cal Poly San Luis Obispo and an archeologist for the Sacramento-based Millennia Archeological Consulting.

"You have to have something significant," Allen says of what it takes to be published in the journal. "You have to have good evidence. As archeologists, you don't get the data you want most of the time. We are typically dealing with fragmented evidence."

Allen says there are two views related to the origins of violence and warfare in humans -- one view that humans in earlier times were peaceful and lived in harmony and a second view that there has always been competition for resources, war and violence.

The second view was confirmed in Allen's study. Using an archeological database of human burials of remains from thousands of Central California inhabitants between going back more than 1,000 years, Allen and his fellow researchers looked at the wound marks from physical traumas they suffered. They also compared that evidence to the environment and looked at the way the communities were socially organized, he says.

They found that California had the highest population density in all of North America, with lots of small groups living in close proximity. There were approximately 100 different languages spoken in California at the time. The data showed how the scarcity of resources and violence correlates.

"When people are stressed out and worried about protecting the group, they are willing to be aggressive," he says. "Violence is about resources for the group."

The data related to the remains showed that about 7 percent of the population at that time had evidence of forced traumas, whether they were shot by an arrow, stabbed or bludgeoned. For females it was 5 percent and for males it was 11 percent, a percentage of violent trauma not even reached during World War II, Allen says.

Allen, who teaches North American and California archeology, says that his research on the origins of violence and warfare speaks to what is happening in modern times.

Read more at Science Daily

A New Theory Explains What's Driving Antarctica's Fastest Melting Glacier

New analysis indicates that local weather conditions, not continental winds as previously thought, could be driving the rapid retreat of the Pine Island Glacier, the fastest melting glacier in Antarctica.

Scientists from the University of East Anglia used records between 2009 and 2014 to determine how local atmospheric conditions are directly affecting the ocean conditions that are rapidly melting the Pine Island Ice Shelf, part of the West Antarctic Ice Sheet that sits at the base of the South Pacific Ocean.

While previous studies suggested that winds coming off of the continental shelf — some 250 miles to the north — were pushing warm waters beneath the western Antarctic, warming the Pine Island Glacier and others from beneath, scientists from the University of East Anglia saw little evidence for that.

"People thought that it was the wind, at the edge of the continental shelf, that was determining how much water was pushed onto the shelf, warming the glacier from beneath," said Ben Webber, an oceanographer at the University of East Anglia and lead researcher on the study.

Instead, by analyzing a five-year set of records, Webber and his team found that local weather, rather than continental winds, were driving the ocean temperatures at a crucial depth between 1,150 to 2,300 feet, the range in which the base of the glacier comes into contact with ocean water.

"Most of the ocean data around Antarctica are snapshots of conditions — and many areas are only visited once every one or two years, if that," Povl Abrahamsen, co-author of the study and an oceanographer at British Antarctic Survey, said in a statement. "A five-year time series," he said, "lets us see what is happening between these snapshots, giving us insights into the processes driving the melting of Pine Island Glacier."

Scientists from the RRS James Clark Ross are lowered onto sea ice, part of a related study of seals in the region and their environment.

The report, published in Nature Communications, comes in the midst of news that another iceberg has broken from the Pine Island Glacier. On Thursday, NASA satellites documented a 1-mile-long iceberg calving from the glacier and moving into the adjacent Amundsen Sea. Scientists have called the incident an "aftershock," resulting from a much bigger separation event in 2015, when an iceberg measuring 278 square miles — the size of Chicago — broke from the Pine Island Glacier.

The glacier, one of the largest in the West Antarctic Ice Sheet, is estimated to account for 20 percent of total ice flow into the ocean — some 19 cubic miles of ice per year, according to NASA. In recent years, as its flow into the ocean has accelerated, the glacier has become symbolic of a fragile, retreating Antarctic glacial system.

Researchers have described the Pine Island Glacier as the "plug" that holds back the expansive West Antarctic Ice Sheet, the melting of which contributes to sea-level rise. According to Webber and his team, this long-ranging data may offer important clues as to how to best measure the retreat of glaciers that could lead to major sea level rise.

While past melting has been offset by accumulation of hail and ice, in recent decades, Webber said, "This system has gone out of balance."

Read more at Discovery News

A 66-Year-Old Albatross Is Still Making Babies

Wisdom, the world's oldest known breeding and banded bird, first tagged in 1956, is still going strong in the fertility department.

According to the U.S. Fish and Wildlife Service's Pacific region (USFWS), the old girl has given birth to a new baby chick at her home base on a wildlife refuge on Hawaii's Midway Atoll – itself one of the oldest atolls in the world.

At least 66 years old, Wisdom, a Laysan albatross, was spotted last December on the atoll, where researchers were excited to find that she was incubating an egg. The proud papa is her mate Akeakamai (a Hawaiian word meaning "seeker of wisdom").

"Wisdom continues to inspire people around the world. She has returned home to Midway Atoll for over six decades and raised at least 30 to 35 chicks," said Bob Peyton, USFWS project leader for Midway Atoll Refuge and Memorial, in a statement.

Albatrosses spend almost 90 percent of their lives in the air, logging thousands of miles of flight in search of food. The USFWS estimates that Wisdom has flown more than 3 million miles during her life. She comes back to the same nesting spot on the Midway Atoll most years, a site that is home to more than 3 million seabirds.

Wisdom is said to be "at least" 66 years old because it's just not possible to be exact, given her history. She was already breeding when she was tagged in 1956, and Laysan albatrosses are not sexually mature until at least age 5 and may not have chicks at all until 8 to 10 years old.

Wisdom is identified by the red, plastic auxiliary band on her right leg.
Wisdom and Akeakamai will stay on the atoll for about seven months while they raise the chick, expending lots of energy flying off to forage for food to feed the new mouth. It's such a time-consuming process that Laysans don't typically lay an egg every year.

That makes Wisdom's latest addition all the more special.

"Because Laysan albatross don't lay eggs every year, and when they do, they raise only one chick at a time, the contribution of even one bird to the population makes a difference," said Peyton.

From Discovery News

A Hidden Continent Dubbed 'Zealandia' May Lie Beneath New Zealand

New Zealand sits atop a previously unknown continent — mostly submerged beneath the South Pacific — that should be recognized with the name Zealandia, scientists said Friday.

Researchers said Zealandia was a distinct geological entity and met all the criteria applied to Earth's seven other continents — elevation above the surrounding area, distinctive geology, a well-defined area and a crust much thicker than that found on the ocean floor.

In a paper published in the Geological Society of America's Journal, GSA Today, they said Zealandia measured five million square kilometers (1.9 million square miles) and was 94 percent underwater.




"That a continent can be so submerged yet unfragmented makes it [useful]...in exploring the cohesion and breakup of continental crust."




While there is no scientific body that formally recognizes continents, Mortimer said he wanted Zealandia to become an accepted part of how the Earth is viewed.



From Discovery News

Feb 16, 2017



The findings will be useful in understanding patients with speech perception deficits and in building computers able to understand auditory and visual speech.








Read more at Science Daily

In the developing ears of opossums, echoes of evolutionary history

When mammalian middle ear bones develop, they begin as part of the arch of cartilage that makes up the embryonic jaw. In reptiles, these structures remain connected to the jaw as developmental processes gradually convert the cartilage to bone.
When we are confronted with the remarkable diversity and complexity of forms among living things -- the lightweight and leathery wings of a bat, the dense networks of genes that work together to produce a functional cell -- it can be hard to imagine how chance mutations and selective processes produced them. If we could rewind evolutionary time, what would we see?

In a new study published in Proceedings of the Royal Society B, animal scientists at the University of Illinois at Urbana-Champaign, King's College London, and the University of Chicago have discovered that hidden in the development of opossums is one possible version of the evolutionary path that led from the simple ears of reptiles to the more elaborative and sensitive structures of mammals, including humans.

Three tiny bones in the middle ear of mammals form a mechanism that converts the air vibrations of sound into the electrical impulses understood by the brain. Three of these bones are known by names that describe their shapes, either in Latin or in English: the malleus (hammer), incus (anvil), and stapes (stirrup). In the simpler ears of reptiles, as well as the shared ancestors of both groups, only the stapes is found in the middle ear, while analogs of the malleus and incus form part of the jaw.

The sharp contrast between the precise structure of these tiny mammalian bones and their non-auditory reptilian counterparts drew the attention of Associate Professor of Animal Biology Karen Sears and postdoctoral researcher Daniel Urban, who led the study. Sears is a member of the Carl R. Woese Institute for Genomic Biology (IGB); Urban is an IGB Fellow.

"We came at this project through the approach of evolutionary developmental biology (evo-devo), which looks at the development of an organism . . . to help understand its evolutionary history," said Urban, explaining their experimental approach. An exciting aspect of the project for him was that it integrated "aspects of paleontology, cellular and molecular biology, developmental biology, and more. We're looking at the problem from more than one angle, utilizing all of these methods to solve the puzzle."

When mammalian middle ear bones develop, they begin as part of the arch of cartilage that makes up the embryonic jaw. In reptiles, these structures remain connected to the jaw as developmental processes gradually convert the cartilage to bone. In mammals, cells within a section of the developing jaw called Meckel's cartilage disappear as the animal grows, freeing the malleus and incus (the hammer and anvil) to reach their positions in the middle ear.

To get a better idea of how the mammalian ear might have evolved, Sears, Urban and their colleagues chose to study the gray short-tailed opossum, a small and charismatic South American marsupial whose key stages of jaw and ear development take place gradually and after birth.

The group first detailed the anatomical progression of middle ear development in their opossums, capturing images that revealed the changing architecture of cartilage and bone. They observed that the progression of structures in the developing opossum jaw and ear appeared to re-enact the evolutionary progression of these structures in the mammalian fossil record.

"It was truly remarkable how well the developmental stages of our extant opossum model organism matched up with the transitional fossils . . . this makes our study organism, the gray short-tailed opossum, a fantastic living model to aid in the understanding of development of long extinct taxa," Urban said. "By using this modern analogue, we can learn so much more about these earlier species and the origins of mammals."

The team also explored changes in gene activity and individual cells that occurred during the breakdown of Meckel's cartilage. They identified a set of genes whose increased activity was correlated with the self-destruction of the cells that connect the future jaw to the future ear.

Among these genes, the researchers focused on a gene called TGF-β for further investigation. When they treated developing opossums with a drug that blocks the signaling of the TGF-β protein, the death of cells within Meckel's cartilage was prevented, and the malleus and incus remained a part of the jaw. With one tweak of gene activity, this one detail of anatomy appeared to have slid backward through evolutionary time.

TGF-β signaling is also known to play a role in the middle ear development of mice. However, the breakdown of cells in Meckel's cartilage in this study of opossums occurred via a different mechanism than that observed in mice: the cells self-destructed, rather than being engulfed by other cells.

"It was both surprising and intriguing to find evidence suggesting that two different cellular mechanisms may be responsible for separating middle ear elements from the jaw in placental and marsupial mammals . . . combined with previous fossil evidence, this implies the [mammalian middle ear] has independently evolved at least four times in total," Urban said. "This would initially seem improbable, except that when we performed functional testing, we showed that this connection (between the middle ear and jaw) can actually be preserved or broken by a relatively minor change in the expression of a single gene."

Read more at Science Daily

Organic Material Discovery Suggests Life Could Exist on Dwarf Planet Ceres

Scientists looking for life beyond Earth have a new target relatively close to home.

The dwarf planet Ceres, which orbits in the Main Asteroid Belt between Mars and Jupiter, has organic compounds on its surface, a paper published in this week's Science shows.

The discovery, made with NASA's orbiting Dawn spacecraft, follows earlier findings that the 590-mile wide Ceres may have an ocean beneath its frozen surface.

"There are speculations about a subsurface ocean on Ceres, similar to Europa or Enceladus," planetary scientist Michael Kuppers, with the European Space Astronomy Center in Madrid, told Seeker.

Europa, a moon of Jupiter, and Enceladus, a moon circling Saturn, are two prime targets in the search for life beyond Earth.

"I do think Ceres is a good target for searches for life outside Earth," Kuppers said. "In addition to distance, the radiation environment is more benign than, for example, Europa."

Dawn lead scientist Christopher Russell, with the University of California Los Angeles, said the discovery means that Ceres should be further explored, but noted that these organic molecules "are a long way from microbial life."

"Ceres should be relatively easy to land on and has a benign environment compared to bodies further out in the solar system," Russell wrote in an email to Seeker. "We could take a small chemical lab to Ceres and analyze its soil and exosphere."

Data collected by Dawn's visible and near-infrared imaging spectrometer showed the organic material matches tar-like compounds such as kerite or asphalitite, lead researcher Maria Cristina De Sanctis, with the National Institute for Astrophysics in Rome, Italy, and colleagues write in the Science paper.

A follow-on analysis showed the organics are native to Ceres, most likely formed by hydrothermal activities beneath the surface.

"These compounds are unlikely to have been delivered from an exterior source in an impact… because the extreme heat from an impact would have destroyed these types of compounds," Science wrote in a summary of the research.

The location of the organics also casts doubt that they arrived via a crashing asteroid or comet.

Scientists found the organics on two sites on Ceres, including on a crater rim.

"The simplest explanation is that they were produced inside Ceres," Russell said.

On a bigger picture, the discovery of organics on Ceres, which orbits nearly three times farther away from the sun than Earth, shows that the building blocks for life were present from the start of the solar system some 4.6 billion years ago.

"If we consider Ceres to be typical of the planetesimals forming about 3 million years after day one of the solar system, the discovery indicates that the starting material in the solar system contained the essential elements… for life," Russell said.

Read more at Discovery News

Dwindling Oxygen in the World's Oceans Could Be Devastating

The world's oceans have lost more than two percent of their oxygen since 1960, with potentially devastating consequences for sea plants and animals, marine scientists said Wednesday.

In those five and a half decades, parts of the oceans devoid of oxygen, called anoxic waters, have quadrupled, said a study in the science journal Nature.

And the production and flow of nitrous oxide, a powerful greenhouse gas, "will probably have increased," it said.

Oceans cover nearly three-quarters of the Earth's surface, provide about half of the oxygen we breathe and feed billions of people every year.

In a comment on the study that Nature also published, research scientist Denis Gilbert of Fisheries and Oceans Canada wrote that a "two percent decrease of ocean oxygen content may not sound like much."

But, he warned, "the implications of this for marine ecosystems could be severe in parts of the ocean where oxygen is already low."

The report found that the largest decrease happened near areas where oxygen was already low, in so-called "dead zones," where oxygen levels declined by four percent every decade.

Most oxygen was lost in the Equatorial and North Pacific Ocean, the Southern Ocean and the South Atlantic Ocean.

"Oxygen data in the Arctic, Equatorial and North Pacific... and Southern Ocean show a continuous decrease, and together are responsible for 60 percent of the global oceanic oxygen loss," the study reported.

The authors said they needed to conduct more research to determine how much of the oxygen loss was due to global warming and how much was related to natural climate cycles.

The study also reiterated an older warning that the loss of oxygen would accelerate — with predictions of a one to seven percent decline by 2100.

The findings "should ring yet more alarm bells about the consequences of global warming," Gilbert said.

Read more at Discovery News

Paleolithic People Body Painted the Dead, Then Smashed Rocks in Death Ritual

Beach pebbles were "killed" 12,000 years ago in death rituals that involved using the stones as spatulas to paint the bodies of the dead, according to excavations in a cave in northern Italy.

The pebbles were uncovered in the Caverna delle Arene Candide, a cave on a steep cliff overlooking the Mediterranean Sea in Liguria.

According to a study published in the Cambridge Archaeological Journal, Paleolithic people living in the area collected oblong pebbles from a nearby beach, used them in the cave to apply ochre onto deceased individuals, and then intentionally broke them.

"The reason for breaking the stones could have been to 'kill' them, discharging them of their symbolic power," co-author Julien Riel-Salvatore, associate professor of anthropology at the University of Montreal, said.

Home to a necropolis containing the remains of some 20 adults and children buried between 13,000 and 11,000 years ago, the cave is located near the present town of Finale Ligure, some 30 miles from Genoa.

The site has been excavated since the 1940s, with archaeologists unearthing more than 600 fragmented pebbles. However, the oblong stones were overlooked and no research was carried out to determine their meaning and function

Researchers at the University of Montreal, Arizona State University and the University of Genoa who excavated a portion of the cave between 2009 and 2011 found 29 limestone pebbles and examined them through macroscopic and microscopic analysis.

It emerged the pebbles were carefully selected on the beach for their polished, flat and oblong morphology. Moreover, traces of ochre were found on the edges and centers of most pebbles, indicating the stones were used as spatulas to decorate the deceased before burial.

The oblong shape allowed "the use of the edges and tip while holding the pebble comfortably and securely in the hand," the researchers wrote.

The funerary ritual ended with the "killing" of the pebbles. Analysis suggested the stones were broken following a specific technique, namely by giving direct blows to their center.

The cave during excavation.
"We experimented by hitting and dropping similarly shaped pebbles in different ways to see which produced the breakage characteristics of the pebbles found in the assemblage," study author Claudine Gravel-Miguel of Arizona State University, told Seeker.

"The pebbles were broken by snapping them on a rock or by hitting their flat surface with a bigger rock," she added.

The "killing" of inanimate objects to break their symbolic power is a well known ritual associated with some prehistoric human burials. Until now, it was thought that this practice only appeared in the Neolithic period in Central Europe, about 8,000 years ago.

"If our interpretation is correct, we've pushed back the earliest evidence of intentional fragmentation of objects in a ritual context by up to 5,000 years," Gravel-Miguel said.

The new evidence may indeed be the earliest instance of ritualistic breakage of artifacts, dating to somewhere between 11,000 and 13,000 years ago.

"At that time people in Liguria were hunter-gatherers but also fishermen. Isotopes analysis of another, much older, burial indicate that 20-25 percent of the food had a marine origin," Roberto Maggi, at Genoa University, told Seeker.

All of the pebble fragments analyzed by the researchers were missing some matching pieces. They suggest that the missing halves were kept by the living as talismans, souvenirs or mementos, to symbolize lasting bonds to the deceased.


"It's the same kind of emotional connection," he added.

According to the researchers, archaeologists usually overlook these objects.

Read more at Discovery News

Feb 15, 2017

Black-hole-powered jets forge fuel for star formation

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered a surprising connection between a supermassive black hole and the galaxy where it resides.








The AGN and Galaxy Growth Connection



Without a significant source of heat, the most massive galaxies in the universe would be forming stars at extreme rates that far exceed observations. Astronomers believe that the heat, in the form of radiation and jets from an actively feeding supermassive black hole, prevents overcooling of the cluster's hot gas atmosphere, suppressing star formation.

This story, however, now appears more complex. In the Phoenix Cluster, Russell and her team found an additional process that ties the galaxy and its black hole together. The radio jets that heat the core of the cluster's hot atmosphere also appear to stimulate the production of the cold gas required to sustain the AGN.

"That's what makes this result so surprising," said Brian McNamara, an astronomer at the University of Waterloo, Ontario, and co-author on the paper. "This supermassive black hole is regulating the growth of the galaxy by blowing bubbles and heating the gases around it. Remarkably, it also is cooling enough gas to feed itself."

This result helps astronomers understand the workings of the cosmic "thermostat" that controls the launching of radio jets from the supermassive black hole.

Read more at Science Daily

Flat-footed fighters: Heel-down posture in great apes and humans confers a fighting advantage

A diagram of an experimental setup to test how a plantigrade (heel-down) stance affects the amount of force a person is able to apply to a pendulum.
Walking on our heels, a feature that separates great apes, including humans, from other primates, confers advantages in fighting, according to a new University of Utah study published today in Biology Open. Although moving from the balls of the feet is important for quickness, standing with heels planted allows more swinging force, according to study lead author and biologist David Carrier, suggesting that aggression may have played a part in shaping our stance.

"This story is one more piece in a broader picture, a suite of distinguishing characters that are consistent with idea that we're specialized at some level for aggressive behavior," Carrier says.

Nature of man debate

Carrier studies biomechanics of how animals move and what the mechanics of movement suggests about the course of an animal's evolution. Such studies in primates and humans addresses a centuries-old controversy about human nature. Is humanity naturally aggressive and confrontational, made less violent through the recent controlling influences of governments, or inherently peaceful and benevolent, turning belligerent only when states and economies led to centralized power and ownership of resources?

Carrier says that when members of the same species compete for resources or mates the stakes are high and physical competition is costly, demanding peak performance from the musculoskeletal and cardiovascular system. The physiological traits that confer advantages in fighting are different from those required for other tasks. "The folks who line up for the Olympic marathon are not built the way the fighters are," he says. "They're not built the way sprinters are. If aggression was important in our past, we should see evidence of it in our anatomy." If the characteristics that distinguish humans and great apes from other primates are not beneficial for fighting, he says, then the hypothesis that aggression was important in our evolutionary past would be falsified. If, however, apes' distinguishing anatomical traits are beneficial to fighting success, then the hypothesis that physical competition helped shaped our evolution would be supported.

Apes' planted heels

Most species of mammals, including most primates, stand, walk and run with their heel elevated above the ground. These stances, called digitigrade and unguligrade, increases the economy of running by lengthening the limb and improving the storage and recovery of elastic strain energy in the tendons and ligaments of the lower limb. The heel-down posture of great apes, called plantigrade, is shared with other species that are less specialized for running, such as bears, wolverines and some rodents.

One hypothesis for the evolution of the great apes' stance has to do with how apes climb and forage in trees. Instead of walking on four limbs along the tops of branches like other primates, apes tend to hang using their arms and walk on their hind legs with balancing support from their arms on other branches. To facilitate this, apes may have shifted their center of mass toward the hind legs, which would yield a plantigrade stance.

Another hypothesis, which Carrier and colleague Christopher Cunningham of the University of Georgia explored, is that a plantigrade stance allows the arms more striking force by increasing the torque, or rotational force that can be applied to the ground.

Putting theory to the test

Carrier and Cunningham set up a force plate for volunteers to stand on that recorded the force applied to the ground while the volunteers struck and pushed a large weighted pendulum. By measuring the velocity that the volunteers imparted to the pendulum, along with the pendulum's known resistance to acceleration, the researchers calculated the work performed. Twelve volunteers completed the task with heels planted and heels up, either with one foot or two. The striking and grappling behaviors studied included lateral strikes and pushes, downward strikes, forward pushes and rearward pulls.

To further illustrate the significance of the rotational force applied by the feet, Carrier says, they also asked volunteers to push the pendulum while standing on a sheet of Teflon and wearing a fuzzy sock. With no ability to exert a rotational force on the ground, the volunteers simply spun in place.

In all cases, the force or energy applied was greater in plantigrade posture than digitigrade, confirming the team's hypothesis that a plantigrade stance allows a person or ape to exert more force and energy, an advantage in fighting. Physical aggression is clearly not the only behavior that influenced the evolution of our feet, Carrier says, but the results of this experiment are consistent with the hypothesis that selection on fighting performance played an important role.

"We're all familiar with the 'fight or flight' response of animals in danger," says Emily Carrington, a program director in the National Science Foundation (NSF)'s Division of Integrative Organismal Systems, which funded the research. "Certain species tend to be good at fighting or fleeing, but not both. This study provides insight into the basis for this trade-off. Animals that are able to use their heels to plant their feet firmly to the ground, like bears, badgers and great apes, are able to deliver stronger blows to their opponents."

Read more at Science Daily

Learning chemistry within Minecraft video game

Using the mod and instructions provided on a Wiki website, players can, for example, harvest and process natural rubber to make pogo sticks, or convert crude oil into a jetpack using distillation, chemical synthesis and manufacturing processes.
A University of Texas at Dallas team is exploring whether teaching real-world science through a popular computer game may offer a more engaging and effective educational approach than traditional concepts of instruction.

In an article recently published in Nature Chemistry, a UT Dallas team -- including a materials scientist, two chemists and a game design expert -- describes how a group of 39 college students from diverse majors played an enhanced version of the popular video game "Minecraft" and learned chemistry in the process, despite being given no in-class science instruction.

Dr. Walter Voit led the team that created "Polycraft World," an adaptation or "mod" for "Minecraft" that allows players to incorporate the properties of chemical elements and compounds into game activities. Using the mod and instructions provided on a Wiki website, players can, for example, harvest and process natural rubber to make pogo sticks, or convert crude oil into a jetpack using distillation, chemical synthesis and manufacturing processes.

"Our goal was to demonstrate the various advantages of presenting educational content in a gaming format," said Voit, a materials science and engineering professor in the Erik Jonsson School of Engineering and Computer Science. "An immersive, cooperative experience like that of 'Polycraft World' may represent the future of education."

Crafting a Teaching Tool

Dr. Ron Smaldone, an assistant professor of chemistry, joined the project to give the mod its accuracy as a chemistry teaching tool. Dr. Christina Thompson, a chemistry lecturer, supervised the course in which the research was conducted, and joined Smaldone in mapping out assembly instructions for increasingly complex compounds. Voit spearheaded a team of programmers that spent a full year on development of the platform.

"Eventually, we got to the point where we said, 'Hey, we can do something really neat with this,'" Voit said. "We could build a comprehensive world teaching people materials science."

For Smaldone and Voit, much of the work was finding in-game objectives that provided a proportional difficulty-reward ratio -- worth the trouble to build, but not too easy.

"If the game is too difficult, people will get frustrated. If it's too easy, they lose interest," Voit said. "If it's just right? It's addicting, it's engaging, it's compelling."

Thompson and Smaldone produced more than 2,000 methods for building more than 100 different polymers from thousands of available chemicals.

"We're taking skills 'Minecraft' gamers already have -- building and assembling things -- and applying them to scientific principles we've programmed," Smaldone said.

Some of the "Polycraft World" gamers became surprisingly proficient in processes for which they had no prior instruction, Voit said.

"We've had complete non-chemists build factories to build polyether ether ketones, which are crazy hard to synthesize," he said. "The demands of the one-hour-a-week class were limited, yet some students went all-out, consuming all this content we put in."

Dr. Monica Evans, an associate dean for graduate programs and associate professor in the School of Arts, Technology, and Emerging Communication, is a co-author of the paper and leads the University's game design program, which is ranked as one of the top programs in the country by The Princeton Review.

"It's quite difficult to make a good video game, much less the rare good game that is also educational," Evans said. "The ingenuity of the 'Polycraft' team is that they've harnessed the global popularity of an existing game, 'Minecraft,' and transformed it into something that is explicitly educational with a university-level subject."

Classroom Instruction Not Included

Voit and Smaldone see "Polycraft World" as an early step on the road to a new format for learning without classroom instruction.

"The games that already exist mostly serve only as a companion to classroom learning," Smaldone said. "The goal here is to make something that stands alone."

A significant advantage of using such a tool comes in the volume of data it returns on student performance.

"We can measure what each player is doing at every time, how long it takes them to mix chemicals, if they're tabbing back and forth to our Wiki, and so on," Voit said. "It gives us all this extra information about how people learn. We can use that to improve teaching."

Smaldone agrees: "With traditional teaching methods, I'd walk into a room of several hundred people, and walk out with the same knowledge of their learning methods," he said. "With our method, it's not just the students learning -- it's the teachers as well, monitoring these player interactions. Even in chemistry, this is a big innovation. Watching how they fail to solve a problem can guide you in how to teach better."

Smaldone admits the concept must overcome doubts held by some that gaming cannot serve useful purposes.

"There's a preconception among some that video games are an inherent evil," he said. "Yet in a rudimentary form, we've made a group of non-chemistry students mildly proficient in understanding polymer chemistry. I have no doubt that if you scaled that up to more students, it would still work."

Voit's plans for the next version of "Polycraft World" will take it beyond teaching chemistry. Perhaps the most ambitious objectives revolve around economics.

"We've worked with several economists, and are developing a monetary system," Voit said. "There will be governments and companies you can form. A government can mint and distribute currency, then accumulate goods to prop up that currency. We'll see teams of people learning how to start companies or countries, how to control supply and demand, and how to sustain an economy.

"Learning about micro- and macroeconomics by actually doing it can impart a much richer understanding of what monetary policy looks like and why."

Read more at Science Daily

Ancient 'Nessie' Look-Alike Gave Birth to Live Babies

The "birth plan" of an ancient Nessie look-alike didn't involve laying a giant egg, but rather delivering a live baby sea monster, a new study finds.

Until now, researchers had thought that the fearsome marine reptile known as Dinocephalosaurus laid eggs, just as birds and crocodiles (its distant relatives) do. But the discovery of the remains of a pregnant, 245-million-year-old Dinocephalosaurus specimen in a Chinese fossil deposit indicates that the reptile gave live birth, the researchers said.

"This is the first-ever evidence of live birth in an animal group previously thought to lay eggs exclusively," said the study's lead researcher, Jun Liu, an associate professor of paleontology at the Hefei University of Technology in China.

Researchers discovered the specimen of the pregnant Dinocephalosaurus in southwestern China's Luoping Biota National Geopark in 2008. During its lifetime in the middle Triassic period, the 13-foot-long (4 meters) marine reptile would have swum throughout the shallow seas of ancient southern China.

Dinocephalosaurus had a long neck and sharp teeth. "It was a fish eater, snaking its long neck from side to side to snatch its prey," Liu told Live Science. "It looks superficially like the legendary Nessie.

"The researchers discovered a fossilized Dinocephalosaurus embryo in the mother's abdomen. The fetus was small — about 12 percent of its mother's body size — but large enough for scientists to discern that its anatomy (for instance, a long neck and elongated ribs) was similar to that of the adult Dinocephalosaurus, the researchers said.

Still, the researchers went to great lengths to determine that the bundle of bones was, in fact, an embryo. First, they noted that the embryo was enclosed within the mother's body, which excluded the possibility that a foreign animal fell on top of her and then fossilized. Second, the embryo's neck was pointing forward. Usually, sea creatures swallow prey headfirst; the mother even had a partially digested fish, whose head was facing backward in her abdomen, the researchers noted.

"The neck-forward position of the embryonic skeleton suggests that the included skeleton was not ingested prey, but was an embryo," the researchers wrote in the study.

Finally, the embryo was curled in a fetal position, just like other known vertebrate embryos during development, the researchers said.

Egg-laying animals typically deposit eggs holding embryos that are much less developed than the one found inside the mother Dinocephalosaurus, the research team noted. In addition, the researchers said that they did not see any evidence of an eggshell near the embryo, further supporting the idea that the Dinocephalosaurus gave live birth, they said.

Dinocephalosaurus was an archosauromorph (Greek for "ruling lizard form"), a relative of the group that includes crocodiles, pterosaurs and dinosaurs, including birds. The new discovery pushes back evidence of reproductive biology in the Archosauromorpha group by 50 million years, Liu said.

In addition, the discovery solves a mystery about egg laying in most archosauromorphs. Previously, researchers were unsure whether archosauromorphs had genetic or developmental barriers preventing live birth, but now they know there isn't a barrier — most archosauromorphs just evolved to lay eggs, Liu said.

Read more at Discovery News

Early Mammal Relative Was the Oldest Venomous Animal on Earth

The oldest venomous vertebrate yet found was a small-dog-sized early relative of mammals named Euchambersia that lived some 260 million years ago, according to findings just published in the journal PLOS One by scientists from University of the Witwatersrand (WITS).

"Today, snakes are notorious for their venomous bite," said the study's lead author Julien Benoit in a statement, "but their fossil record vanishes in the depth of geological times at about 167 million years ago. So, at 260 million years ago, the Euchambersia evolved venom – more than a 100 million years before the very first snake was even born."

Euchambersia was about 16-20 inches long (40-50 centimeters) and trod the land of modern-day South Africa well before the dinosaurs. The animal has long been supposed to have been venomous, based on characteristics of its teeth and upper jaw, but the hypothesis had not until now been tested.

The WITS researchers used CT scanning and 3D imaging on the only two fossilized skulls in existence of Euchambersia. Sure enough, under the detailed examination they found the small creature's anatomy had characteristics consonant with making venom.

The scientists found a deep, wide space in the upper jaw called a fossa that would have held a venom gland. It was connected to the canine teeth and mouth by bony grooves and canals. Finally, ridges on the incisors and canine teeth completed the venom delivery system.

Euchambersia did not deliver its venom in the same way snakes deliver their payload, the scientists found. While reptiles such as the cobras and vipers we all know and run from today inject venom through needle-like grooves in the their teeth, Euchambersia's venom went directly into its mouth and the animal used the ridges on its canines to pass the poison to its victims.

An early paleontologist named Franz Nopcsa would likely be gladdened by the findings, were he alive today. Nopcsa in 1933 studied an Euchambersia fossil and averred that the creature was likely the oldest venomous animal anyone had ever documented. But venom glands don't fossilize, and fancy CAT scans and 3D imaging systems did not exist in his day, so he could never know for sure if he was right.

"The results? Nopcsa was right," Benoit wrote in The Conversation, naming Euchambersia "officially the oldest venomous animal that ever roamed the Earth."

"Even more intriguing is that Euchambersia is related to early mammals, not to snakes," Benoit noted in the piece, adding that some scientists think all mammals were once venomous but over time lost their venom-producing glands, leaving a comparative few modern mammals – vampire bats, some shrews, for example – with poisonous ways.

From Discovery News

Feb 14, 2017

Technology puts 'touch' into long-distance relationships

A SIAT graduate student Azadeh Foirghani demonstrates the Flex N Feel glove.
Long-distance couples can share a walk, watch movies together, and even give each other a massage, using new technologies being developed in Carman Neustaedter's Simon Fraser University lab.

It's all about feeling connected, says Neustaedter, an associate professor in SFU's School of Interactive Arts and Technology (SIAT). Student researchers in his Surrey campus-based Connections Lab are working on myriad solutions.

Among them, researchers have designed a pair of interconnected gloves called Flex-N-Feel. When fingers 'flex' in one glove, the actions are transmitted to a remote partner wearing the other. The glove's tactile sensors allow the wearer to 'feel' the movements.

To capture the flex actions, the sensors are attached to a microcontroller. The sensors provide a value for each bend, and are transmitted to the 'feel' glove using a WiFi module.


"Users can make intimate gestures such as touching the face, holding hands, and giving a hug," says Neustaedter. "The act of bending or flexing one's finger is a gentle and subtle way to mimic touch."


Other projects also focus on shared experiences, including a virtual reality video conferencing system that lets one "see through the eyes" of a remote partner, and another that enables users to video-stream a remote partner's activities to a long-distance partner at home (called Be With Me).


They've embedded a robot, designed by Suitable Technologies, into several Vancouver homes. There, it connects to countries around the world, including India and Singapore. Researchers continue to monitor how the robot is used. One long-distance couple plans a Valentine's Day 'date' while one partner is in Vancouver, and the other, on Vancouver Island.

"The focus here is providing that connection, and in this case, a kind of physical body," says Neustaedter, who has designed and built eight next-generation telepresence systems for families, and is author of Connecting Families: The Impact of New Communication Technologies on Domestic Life (2012). He has also spent more than a decade studying workplace collaborations over distance, including telepresence attendance at international conferences.

Read more at Science Daily

Kepler, don't give up on the hunt for exomoons

This simulation shows the collision of two celestial bodies, ejecting enough debris into orbit to form a moon large enough for the Kelper spacecraft to detect.
The Kepler spacecraft has been prolific in its search for planets outside our solar system, known as exoplanets, discovering thousands since its launch in 2009. But the hunt for moons orbiting these exoplanets, or exomoons, is vastly more challenging. While no exomoons have been found to date, a new study shows that the search is not futile.

Researchers have demonstrated for the first time that it is possible for a planetary collision to form a moon large enough for Kepler to detect. Lawrence Livermore National Laboratory physicist Megan Bruk Syal and Amy Barr of the Planetary Science Institute conducted a series of around 30 simulations to explore how various factors affect moon creation. In the end, they were able to narrow in on a set of conditions that would create satellites much larger than Earth's moon. The study -- "Formation of massive rocky exomoons by giant impact" -- will appear in the May issue of the Royal Astronomical Society's Monthly Notices.

"We weren't modeling something that's been observed," Syal said. "This problem was more abstract, more theoretical. It took a while, but once we were able to generate these massive moons, we were pretty excited."

The leading thinking on the creation of Earth's moon is that a planetoid the size of Mars collided with a smaller proto-Earth about 4.5 billion years ago, ejecting significant debris into orbit that consolidated into a disk and eventually the moon. The result was a satellite that is about 1.2 percent of Earth's mass. But in order for an exomoon to be large enough for Kepler to detect with existing transit techniques, it would need to be at least 10 percent the size of Earth, according to detection criteria from the "Hunt for Exomoons with Kepler" project.

Previous research on Earth's moon considered factors like the angle of impact and relative masses of colliding bodies. As the impact angle becomes more oblique, more material is injected into orbit. Similarly, as the two bodies approach equal size, the disk mass increases. But this study found that a third factor -- impact velocity -- also plays a crucial role in determining how large a moon an impact can create.

"Prior research has focused on a fairly narrow set of conditions, favorable to forming Earth's moon," Syal said. "This is the first study to consider a much wider array of impact scenarios, exploring the full range of what may be possible in other planetary systems. There is a lot of uncharted territory."

Read more at Science Daily

What drives universe's expansion?

Andromeda Galaxy

Tests using advanced technology could resolve a longstanding puzzle over what is driving the accelerated expansion of the Universe.

Researchers have long sought to determine how the Universe's accelerated expansion is being driven. Calculations in a new study could help to explain whether dark energy- as required by Einstein's theory of general relativity -- or a revised theory of gravity are responsible.

Einstein's theory, which describes gravity as distortions of space and time, included a mathematical element known as a Cosmological Constant. Einstein originally introduced it to explain a static universe, but discarded his mathematical factor as a blunder after it was discovered that our Universe is expanding.

Research carried out two decades ago, however, showed that this expansion is accelerating, which suggests that Einstein's Constant may still have a part to play in accounting for dark energy. Without dark energy, the acceleration implies a failure of Einstein's theory of gravity across the largest distances in our Universe.

Scientists from the University of Edinburgh have discovered that the puzzle could be resolved by determining the speed of gravity in the cosmos from a study of gravitational waves -space-time ripples propagating through the universe.

The researchers' calculations show that if gravitational waves are found to travel at the speed of light, this would rule out alternative gravity theories, with no dark energy, in support of Einstein's Cosmological Constant. If however, their speed differs from that of light, then Einstein's theory must be revised.

Such an experiment could be carried out by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US, whose twin detectors, 2000 miles apart, directly detected gravitational waves for the first time in 2015.

Experiments at the facilities planned for this year could resolve the question in time for the 100th anniversary of Einstein's Constant.

The study, published in Physics Letters B, was supported by the UK Science Technology Facilities Council, the Swiss National Science Foundation, and the Portuguese Foundation of Science and Technology.

Read more at Science Daily

Climate Change Is Threatening Many More Animals Than We Thought

Nearly half of endangered mammals and a quarter of birds are already harmed by climate change – a much bigger segment than previously thought, researchers have found.

Endangered primates and elephants are among the groups squeezed hardest by global warming, partly because they reproduce slowly and thus take longer to adapt to rapid environmental changes, they reported.

While most studies seek to predict global warming's future impact on animal survival, the new analysis found that for "large numbers" of threatened species, the damage was already being done.

The data suggests that "the impact of climate change on mammals and birds in the recent past is currently greatly under-appreciated," said a study in the journal Nature Climate Change this week.

According to co-author James Watson of the Wildlife Conservation Society, "something significant needs to happen now to stop species going extinct."

"Climate change is not a future threat anymore," he added.

Researchers had amassed data from 136 previous studies looking at 120 mammal and 569 bird species.

They compared documented changes in climate with growth or decline in population sizes, geographic ranges, body mass, and reproductive and survival rates.

The team then extrapolated the data to all land mammals and birds listed as threatened by the International Union for Conservation of Nature (IUCN).

Of the 873 listed mammal species, 414 (47 percent) have likely "responded negatively" to climate change, and 298 (just over 23 percent) of 1,272 birds, the researchers found.

Climate change can affect animals by limiting food and water, spreading disease and shrinking living space.

Only seven percent of mammals and four percent of birds identified by the study were recognised by the IUCN as threatened by "climate change and severe weather", the authors said.

"We recommend that research and conservation efforts give greater attention to the 'here and now' of climate change impacts on life on Earth," they wrote.

"Conservation managers, planners and policy makers must take this into account in efforts to safeguard the future of biodiversity."

Along with elephants and apes, the team found that marsupials were among the worst affected mammals. Many had evolved, like primates, in stable tropical areas now becoming more volatile due to climate change.

Many of the hardest-hit bird species lived in aquatic environments, which are considered among the most vulnerable to temperature increase, the researchers added.

Meanwhile rodents that can burrow and avoid extreme weather conditions will be less vulnerable than other mammals to climate change, the team said.

Read more at Discovery News

Feb 13, 2017

New theory explains how Earth's inner core remains solid despite extreme heat

Even though it is hotter than the surface of the Sun, the crystallized iron core of Earth remains solid. A new study from KTH Royal Institute of Technology in Sweden may finally settle a longstanding debate over how that's possible, as well as why seismic waves travel at higher speeds between the planet's poles than through the equator.

Spinning within Earth's molten core is a crystal ball -- actually a mass formation of almost pure crystallized iron -- nearly the size of the moon. Understanding this strange, unobservable feature of our planet depends on knowing the atomic structure of these crystals -- something scientists have been trying to do for years.


At Earth's core, where pressure is 3.5 million times higher than surface pressure -- and temperatures are some 6,000 degrees higher -- scientists have proposed that the atomic architecture of iron must be hexagonal. Whether BCC iron exists in the center of Earth has been debated for the last 30 years, and a recent 2014 study ruled it out, arguing that BCC would be unstable under such conditions.

However, in a recent study published in Nature Geosciences, researchers at KTH found that iron at Earth's core is indeed in the BCC phase. Anatoly Belonoshko, a researcher in the Department of Physics at KTH, says that when the researchers looked into larger computational samples of iron than studied previously, characteristics of the BCC iron that were thought to render it unstable wound up doing just the opposite.

"Under conditions in Earth's core, BCC iron exhibits a pattern of atomic diffusion never before observed," Belonoshko says.

Belonoshko says the data also shows that pure iron likely accounts for 96 percent of the inner core's composition, along with nickel and possibly light elements.

Their conclusions are drawn from laborious computer simulations performed using Triolith, one of the largest Swedish supercomputers. These simulations allowed them to reinterpret observations collected three years ago at Livermore Lawrence National Laboratory in California. "It appears that the experimental data confirming the stability of BCC iron in the Core were in front of us -- we just did not know what that really meant," he says.

At low temperature BCC is unstable and crystalline planes slide out of the ideal BCC structure. But at high temperatures, the stabilization of these structures begins much like a card game -- with the shuffling of a "deck." Belonoshko says that in the extreme heat of the core, atoms no longer belong to planes because of the high amplitude of atomic motion.

"The sliding of these planes is a bit like shuffling a deck of cards," he explains. "Even though the cards are put in different positions, the deck is still a deck. Likewise, the BCC iron retains its cubic structure."

Such a shuffling leads to an enormous increase in the distribution of molecules and energy -- which leads to increasing entropy, or the distribution of energy states. That, in turn, makes the BCC stable.

Normally, diffusion destroys crystal structures turning them into liquid. In this case, diffusion allows iron to preserve the BCC structure. "The BCC phase goes by the motto: 'What does not kill me makes me stronger'," Belonoshko says. "The instability kills the BCC phase at low temperature, but makes the BCC phase stable at high temperature."

He says that this diffusion also explains why Earth's core is anisotropic -- that is, it has a texture that is directional -- like the grain of wood. Anisotropy explains why seismic waves travel faster between Earth's poles, than through the equator.

"The unique features of the Fe BCC phase, such as high-temperature self-diffusion even in a pure solid iron, might be responsible for the formation of large-scale anisotropic structures needed to explain Earth inner core anisotropy," he says. "The diffusion allows easy texturing of iron in response to any stress."

Read more at Science Daily

Old into new: Geneticists track the evolution of parenting

University of Georgia researchers have confirmed that becoming a parent brings about more than just the obvious offspring -- it also rewires the parents' brain.

The study, published this month in Nature Communications, finds that the transition from a non-parenting state to a parenting state reflects differences in neuropeptides generally associated with mating, feeding, aggression and increased social tolerance.

Neuropeptides are small proteins that allow neurons in the brain to communicate with each other; they also influence behavior.

The team's research -- tested on an insect, the burying beetle Nicrophorus vespilloides -- provides a predictive framework for studying the genetics of parenting and social interactions.

The burying beetle is intimately involved in raising its children, including regurgitating food to its begging offspring.

"We tested the idea that we could predict the genetic pathways involved in parenting based on old predictions from ethologists in the 1960s and 1970s," said the study's lead author Allen Moore, Distinguished Research Professor and head of the department of genetics. "When [burying beetle] parents feed their babies, they are feeding others rather than themselves and so genes that influence food-seeking behavior are likely to be involved."

Behavioral scientists predicted that genetic changes occur over time to develop parenting in a species. Based on this hypothesis, Moore's team sequenced and assembled the genome of the burying beetle and measured the abundance of neuropeptides. They theorized that behaviors related to parenting stemmed from alterations in existing genes rather than the evolution of new ones.

By looking at parenting and non-parenting beetles, their tests indicated that neuropeptides changed in abundance during parenting.

"When new traits evolve, evolution tends to modify existing genetic pathways rather than create new genes," Moore said.

The research, Moore said, suggests that many of the genes influencing parenting will be the same across many species. The commonality among organisms will help researchers identify genetic pathways important to parenting.

Read more at Science Daily

3,000-Year-Old Child Footprints Found at Site of Ancient Egyptian Palace

Mysterious, 3,000-year-old footprints of ancient Egyptian children have emerged alongside rare painting fragments, at what appears to be the site of a royal palace or temple.

The prints were uncovered at the remains of a large building in the fabled Pi-Ramesse, a city which was Egypt's capital during the reign of the King Ramses II.

Mahmoud Afifi, head of the Ancient Egyptian Antiquities department, described the building complex as "truly monumental."

"It is likely to be a temple or a palace," he said.

As they excavated the structure, a team of archaeologists from the Roemer-Pelizaeus Museum in Hildesheim, Germany, found a mortar pit measuring approximately 8 by 26 feet.

At the bottom of the pit, a layer of mortar was still present, etched with the small prints.

"The children's footprints had a size of 15-17 centimeters (5.9 – 6.6 inches) , thus relating to children between 3 and 5 years of age if one follows charts for modern children," Henning Franzmeier, field director of the Qantir-Piramesse project in Egypt's Nile Delta, told Seeker.

The archaeologists cannot yet say if there was more than one child.

"The differences in size are not big enough for us to clearly differentiate. And they are also not so well preserved that we could distinguish so far any other features of the feet," Franzmeier said.

Built on an island in the easternmost Nile branch, some 65 miles northeast of Cairo, Pi-Ramesse (modern Qantir) flourished during the 66 years of Ramses II's reign and for more than a century after his death.

"The city had an extension of about 10 square miles, making it the one of the largest settlements of the Late Bronze Age in the Eastern Mediterranean and the Middle East," Franzmeier said.

However, toward the end of the 20th Dynasty the city began to decline, and in the 21st Dynasty (1075–950 BC) the capital was moved about 18 miles north to Tanis.

Some painting fragments found in the mortar pit.
The city's monuments and temples were plundered, their stones recycled at Tanis and other sites. Abandoned and forgotten, Pi-Ramesse remained lost in the desert sand for thousands of years.

Today nothing of the city's glorious past can be found at the surface. However, its monumental remains have been identified through magnetic measurements. These can detect the differences in the magnetic susceptibility of various materials in the ground.

"Therefore we are able to detect walls, especially those made of mud bricks," Franzmeier said.

A major investigation was carried out between 1996 and 2012 by geophysicist Helmut Becker and colleagues at the Bavarian State Office for the Preservation of Monuments. The team conducted an extensive survey covering about 1 square mile — one of the largest such surveys ever carried out in archaeology.

Among the features recorded was the building complex excavated by Franzmeier's team. Measuring about 820 by 490 feet, the structure is similar in size to the funerary temple, known as the Ramesseum, which was dedicated to Ramesses II in Thebes,

"The layout of the central part definitely resembles a temple," Franzmeier said.

The reason for the children's presence remains a mystery. Although no modern concept of banning child labor was in place, the footprints seem to be too small even for children who may have been working.

On the other hand, it appears unlikely that royal kids were left to play in the mud and mortar.

In the next season Franzmeier's team will excavate more of the area and larger parts of the mortar pit, which has only been partially cleaned.

"We are planning to involve specialists which would analyze the footprints and will hopefully find out a little more," Franzmeier said.

The pit where the prints were found was also filled with smashed pieces of painted wall plaster. Unfortunately, most fragments are very small, so no motifs were recognized.

Read more at Discovery News