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Wednesday, March 1, 2017

Mollusk Graveyards Are Time Machines to the Oceans' Pristine Past

A University of Florida study shows that mollusk fossils provide a reliable measure of human-driven changes in marine ecosystems and shifts in ocean biodiversity across time and space.

Collecting data from the shells of dead mollusks is a low-cost, low-impact way of glimpsing how oceans looked before pollution, habitat loss, acidification and explosive algae growth threatened marine life worldwide. Mollusk fossils can inform current and future conservation and restoration efforts, said Michal Kowalewski, the Jon L. and Beverly A. Thompson Chair of Invertebrate Paleontology at the Florida Museum of Natural History on the UF campus and the study's principal investigator.

"These fossils are like marine time machines that can unveil bygone habitats that existed before humans altered them," he said. "Shells can help us understand past marine life and more precisely gauge recent changes in marine ecosystems. Fossils are the only direct way of learning what these ecosystems looked like before human activities altered them."

Florida Museum of Natural History researchers found that mollusk graveyards accurately recorded patterns of biodiversity across a range of marine habitats.

Photo by Carrie Tyler

Because mollusks, such as conchs, oysters and mussels, are abundant and often have sturdy shells, their remains litter much of the Earth's sea floor. These mollusk graveyards offer a treasure trove of information about the state of oceans over thousands of years, recording patterns in the diversity and distribution of marine animals across and within habitats with surprising accuracy, said Carrie Tyler, who conducted the work as a postdoctoral researcher at the museum and is now an assistant professor of invertebrate paleontology at the Miami University of Ohio.

Many scientists have questioned whether mollusks alone can provide insights into entire ecosystems. Currents and storms can carry organisms' remains away, while others are fragmented, destroyed or--in the case of soft-bodied animals such as jellyfish and worms--completely absent from the fossil record. Also, shell graveyards are often a mix of specimens from many centuries, which can muddle ecological interpretations.

"The remains that do accumulate only represent part of the whole ecosystem," said Tyler, the study's lead author. "These and other factors can create bias in the fossil record, making comparisons between modern and fossil ecosystems suspect."

To test mollusks' ability to faithfully record biodiversity, Tyler and Kowalewski surveyed living and dead marine animals at 51 sites off the coast of North Carolina, selecting spots that differed in environmental conditions and the kinds of species they hosted. Aiming to capture a range of habitats, the researchers surveyed inlets, estuaries and open ocean, from the coast to miles offshore. They tested whether changes in diversity from place to place were accurately recorded by the newly-forming fossil record. They also assessed whether mollusks could reflect these ecosystem-wide changes.

Tyler and Kowalewski found that live and dead mollusks accurately recorded spatial diversity patterns in both living and fossil communities of marine bottom-dwelling organisms. By comparing present-day communities of marine animals to dead remains, they discovered that mollusk shells alone accurately reconstructed differences in ecosystems across habitats and correctly tracked changes in the distribution of animals from shallow to deeper waters.

A unique aspect of the study, Kowalewski said, was investigating whether mollusks reliably recorded shifts in entire communities of bottom-dwelling animals across habitats and space.

"If we look at many spots on the sea floor and evaluate how living bottom-dwelling animals vary in space, do we recover the same information by analyzing shell remains of only one type of organism, such as mollusks? Our data indicate that we can," he said. "The good match between dead and living organisms suggests that we can use historical data to look at not just which species existed in the past, but also whether the spatial structure of these ecosystems changed."

Understanding how the diversity of species changes within habitats and from site to site across the sea floor is crucial for effectively planning protected marine areas and coastal resource management, Kowalewski said. It is also a part of an increased effort to approach ecosystem conservation more broadly, focusing not only on the vulnerability of individual species but also on how species congregate within and across habitats.

Whether mollusks can provide insights into an ecosystem's more mobile animals, such as fish, remains unclear. But regardless of how much mollusks can tell us about fish, turtles or mammals, understanding marine invertebrate biodiversity is critical to restoring and protecting ocean health, Tyler said.

"Invertebrates provide food for fish, birds and marine mammals, purify water and are important for commercial fisheries," she said. "The ability to use mollusks to understand how invertebrate communities are changing in response to human activities can help us protect and manage ecosystems that are critical for maintaining life in the oceans and to society."

Contacts and sources:
Michal Kowalewski
University of Florida

The study was published in Proceedings of the Royal Society B and is available at http://dx.doi.org/10.1098/rspb.2016.2839. Funding from the National Science Foundation helped support the research.

166 Million Year Old Fossil of Belemnoteuthis Antiquus, Ancient Squid Ancestor

Octopus, cuttlefish and squid are well known in the invertebrate world. With their ink-squirting decoy technique, ability to change colour, bizarre body plan and remarkable intelligence they highlight that lacking a back-bone doesn't always mean lacking sophistication.

Examining their deep evolutionary past, researchers have been spoiled by their generous fossil record, as demonstrated by drawer after drawer of ammonites and belemnites in every natural history museum shop. But, the mostly shell-less modern cephalopods have been less easy to understand.

Now a new study, led by researchers from the University of Bristol, has found out how these remarkable creatures evolved by comparing their fossil records with the evolutionary history chronicled in their gene sequences to shed light on their origins.

Belemnoteuthis antiquus NHM OR25966, a 166 million year old exceptionally preserved extinct squid-relative was found near Bristol (Christian Malford). These ancient cephalopods with their large internal shell were not as fast as their recently evolved relatives, which survived until today's squid and cuttlefish.

Credit: Jonathan Jackson and Zoë Hughes, NHMUK

Published n Proceedings of the Royal Society B, it shows that the cephalopods diversified into the familiar modern octopuses, cuttlefish and squid during a time of great change in the marine world, known as the Mesozoic Marine Revolution, 160 to 100 million years in the past.

Lead author, Al Tanner, a PhD student at the University of Bristol's School of Biological Sciences, is a molecular biologist and bioinformatician at the Bristol Palaeobiology Research Group--a world leading evolutionary research group.

He said: "On land this was the time of the dinosaurs, but beneath the seas, ecologies were changing rapidly. Fish, squid and their predators were locked in evolutionary 'arms-races', leading to increasingly speedy and agile predators and prey.

"The cephalopods are now known to have also been caught up in this major transition, evolving to lose the shells of their ancestors and develop as dynamic and uniquely adapted marine animals."

The researchers used a technique called molecular clocks to investigate the timing of when the groups split from each other. Bristol co-author, Professor Davide Pisani, added: "Complex Bayesian models take all sorts of information into account to build a tree of evolutionary time.

"The key element of molecular clocks though is the fact that mutations steadily accumulate in genetic material over time - so by figuring out how many mutations per million years you find, and how it may vary between different groups, we can estimate evolutionary time."

Al Tanner said: "The molecular clock results can be compared to the fossil record. What we see is that while there is some uncertainty in molecular clock estimates, octopuses and squid appear during the Mesozoic Marine Revolution and the two lines of evidence come together to tell the tale of evolution".

Co-author Dr Jakob Vinther said: "By having a reduced internal skeleton compared to their ancient relatives, the modern squids and octopuses could compress their body and more efficiently jet away leaving a baffling cloud of ink with the attacking predator. Before the predator realises what has happened and gains clear view again, the squid is far out of sight."

Al Tanner added: "The research exemplifies why evolutionary biologists are increasingly seeking to understand deep history from the combined study of both living organisms and the geological record. Through this synoptic view, so called molecular palaeontologists are transforming our understanding of how life became so complex and diverse."

Contacts and sources:
Al Tanner
University of Bristol

A Peek at a Phenomenon Called Ageing That Leads to More Powerful Earthquakes

Scientists have gotten better at predicting where earthquakes will occur, but they’re still in the dark about when they will strike and how devastating they will be.

In the search for clues that will help them better understand earthquakes, scientists at the University of Pennsylvania are studying a phenomenon called ageing. In ageing, the longer that materials are in contact with each other, the more force is required to move them. This resistance is called static friction. The longer something, such as a fault, is sitting still, the more static friction builds up and the stronger the fault gets.

Even when the fault remains still, tectonic motion is still occurring; stress builds up in the fault as the plates shift until finally they shift so much that they exceed the static friction force and begin to slide. Because the fault grew stronger with time, the stress can build up to large levels, and a huge amount of energy is then released in the form of a powerful quake.

Photo: Ian Kluft

“This ageing mechanism is critical in underlying the unstable behavior of faults that lead to earthquakes,” said Robert Carpick, the John Henry Towne Professor and chair of the Department of Mechanical Engineering and Applied Mechanics in Penn’s School of Engineering and Applied Science. “If you didn't have ageing, then the fault would move very easily and so you'd get much smaller earthquakes happening more frequently, or maybe even just smooth motion. Ageing leads to the occurrence of infrequent, large earthquakes that can be devastating.”

Scientists have been studying the movement of faults and ageing in geological materials at the macroscale for decades, producing phenomenological theories and models to describe their experimental results. But there’s a problem when it comes to these models.

​​​​​​​“The models are not fundamental, not physically based, which means we cannot derive those models from basic physics,” said Kaiwen Tian, a physics graduate student in Penn’s School of Arts & Sciences.

But a Penn-based project seeks to understand the friction of rocks from a more physical point of view at the nanoscale.

In their most recent paper, published in Physical Review Letters, the researchers verified the first fundamental theory to describe ageing and explain what happens when load increases.

The research was led by Tian and Carpick. David Goldsby, an associate professor in the Department of Earth and Environmental Science at Penn; Izabela Szlufarska, a professor of materials science and engineering at the University of Wisconsin-Madison; UW alumnus Yun Liu; and Nitya Gosvami, now an assistant professor in the Department of Applied Mechanics at IIT Delhi, also contributed to the study.

Previous work from the group found that static friction is logarithmic with time. That means that if materials are in contact for 10 times longer, then the friction force required to move them doubles. While scientists had seen this behavior of rocks and geological materials at the macroscopic scale, these researchers observed it at the nanoscale.

In this new study, the researchers varied the amount of normal force on the materials to find out how load affects the ageing behavior.

“That's a very important question because load may have two effects,” Tian said. “If you increase load, you will increase contact area. It may also affect the local pressure.”

To study this, the researchers used an atomic force microscope to investigate bonding strength where two surfaces meet. They used silicon oxide because it is a primary component of many rock materials. Using the small nanoscale tip of the AFM ensures that the interface is composed of a single contact point, making it easier to estimate the stresses and contact area.

They brought a nanoscale tip made from silicon oxide into contact with a silicon oxide sample and held it there. After enough time passed, they slid the tip and measured the force required to initiate sliding. Carpick said this is analogous to putting a block on the floor, letting it sit for a while, and then pushing it and measuring how much force it takes for the block to start moving.

They observed what happened when they pushed harder in the normal direction, increasing the load. They found that they doubled the normal force, and then the friction force required also doubled.

Explaining it required looking very carefully the mechanism leading to this increase in friction force.

“The key,” Carpick said, “is we showed in our results how the dependence of the friction force on the holding time and the dependence of the friction force on the load combine. This was consistent with a model that assumes that the friction force is going up because we're getting chemical bonds forming at the interface, so the number of those bonds increase with time. And, when we push harder, what we're doing is increasing the area of contact between the tip and the sample, causing friction to go up with normal force.”

Prior to this research, it had been suggested that pushing harder might also cause those bonds to form more easily. The researchers found that this wasn’t the case: to a good approximation, increasing the normal force simply increases the amount of contact and the number of sites where atoms can react.

Currently, the group is looking at what happens when the tip sits on the sample for very short amounts of time. Previously they had been looking at hold times from one-tenth of a second to as much as 100 seconds. But now they’re looking at timescales even shorter than one-tenth of a second.

By looking at very short timescales, they can gain insights into the details of the energetics of the chemical bonds to see if some bonds can form easily and if others take longer to form. Studying bonds that form easily is important because those are the first bonds to form and might provide insight into what happens at the very beginning of the contact.

In addition to providing a better understanding of earthquakes, this work could lead to more efficient nano-devices. Because many micro- and nano-devices are made from silicon, understanding friction is key to getting those devices to function more smoothly.

But, most important, the researchers hope that somewhere down the line, a better understanding of ageing will enable them to predict when earthquakes will occur.

“Earthquake locations can be predicted fairly well,” Carpick said, “but when an earthquake is going to happen is very difficult to predict, and this is largely because there's a lack of physical understanding of the frictional mechanisms behind the earthquakes. We have long way to go to connect this work to earthquakes. However, this work gives us more fundamental insights into the mechanism behind this ageing and, in the long term, we think these kinds of insights could help us predict earthquakes and other frictional phenomena better.”

This research was supported by a grant from the Earth Sciences Division of the National Science Foundation.

Contacts and sources:
Ali Sundermier University of Pennsylvania

More Than One Mosquito Species May Be Spreading Zika Virus; AI predicts 35 Zika vectors

Zika virus could be transmitted by more mosquito species than those currently known, according to a new predictive model created by ecologists at the University of Georgia and the Cary Institute of Ecosystem Studies. Their findings, published today in the journal eLife, offer a list of 26 additional potential candidate species--including seven that occur in the continental United States--that the authors suggest should be the first priority for further research.

"The biggest take home message is that these are the species that we need to prioritize," said lead author Michelle V. Evans, a UGA doctoral student in ecology and conservation. "Especially as we're in the slower part of the mosquito season, now is the time to catch up so we're prepared for the summer."

Targeting Zika's potential vectors--species that can transmit the virus from one host to another--is an urgent need, given its explosive spread and the devastating health effects associated with it. It's also time-consuming and expensive, requiring the collection of mosquitoes in affected areas, testing them to see which ones are carrying the virus, and conducting laboratory studies.

Credit: Pixabay

The new model could streamline the initial step of pinpointing Zika vectors.

"What we've done is to draw up a list of potential vector candidates based on the associations with viruses that they've had in the past as well as other traits that are specific to that species," said paper co-author Courtney C. Murdock, an assistant professor in the UGA School of Veterinary Medicine and Odum School of Ecology. "That allows us to have a predictive framework to effectively get a list of candidate species without having to search blindly."

The researchers developed their model using machine learning, a form of artificial intelligence that is particularly useful for finding patterns in large, complicated data sets. It builds on work done by co-author Barbara A. Han of the Cary Institute, who has used similar methods to predict bat and rodent reservoirs of disease based on life history traits.

Data used in the model consisted of information about the traits of flaviviruses--the family that includes Zika, yellow fever and dengue--and all the mosquito species that have ever been associated with them. For mosquito species, these included general traits like subgenus and geographic distribution as well as traits relevant to the ability of each species to transmit disease, such as proximity to human populations, whether they typically bite humans and how many different viruses they are known to transmit.

For viruses, traits included how many different mosquito species they infect, whether they have ever infected humans and the severity of the diseases they cause.

Analyzing known mosquito-virus pairs, the researchers found that certain traits were strong predictors of whether a linkage would form. The most important of these for mosquitoes were the subgenus, the continents it occurred on and the number of viruses it was able to transmit. For viruses, the most important trait was the number of mosquito species able to act as a vector.

Based on what they learned, they used the model to test the combination of Zika virus with all the mosquito species known to transmit at least one flavivirus. The model found 35 predicted Zika vectors, including 26 previously unsuspected possibilities.

Seven of those species occur in the continental U.S., with ranges that in some cases differ from those of the known vectors. Evans and Murdock cautioned strongly against assuming that this means that Zika will spread to all those areas.

"We're really solely looking at vector competence, which is only one small part of disease risk," Evans said. "It's one factor out of many, and not even the most important one. I want to stress that all of these are just predictions that need to be validated by empirical work. We are suggesting that people who are doing that work should focus on these species first," she said.

"Ecologists have long known that everything is connected to everything else, and are pretty good, I think, at sifting out where that matters from where it doesn't," said senior author John M. Drake, a professor in the Odum School and director of the UGA Center for the Ecology of Infectious Diseases. "This work highlights that ecological way of thinking and why it's important in understanding infectious diseases."

Contacts and sources:
John M. Drake
University of Georgia

The paper's other co-author is Tad A. Dallas of the University of California-Davis.

The paper, "Data-driven identification of potential Zika virus vectors," is available online at http://dx.doi.org/10.7554/eLife.22053.

New Study Questions on How the Atmosphere and Oceans Formed

A new study led by The Australian National University (ANU) has found seawater cycles throughout the Earth's interior down to 2,900km, much deeper than previously thought, reopening questions about how the atmosphere and oceans formed.

A popular theory is that the atmosphere and oceans formed by releasing water and gases from the Earth's mantle through volcanic activity during the planet's first 100 million years.

But lead researcher Dr Mark Kendrick from ANU said the new study provided evidence to question this theory.

"Our findings make alternative theories for the origin of the atmosphere and oceans equally plausible, such as icy comets or meteorites bringing water to the Earth," said Dr Kendrick from the ANU Research School of Earth Sciences.

Dr. Mark Kendrick is shown with a sample of volcanic glass.

Credit: Stuart Hay, ANU

Seawater is introduced into the Earth's interior when two tectonic plates converge and one plate is pushed underneath the other into the mantle.

The study has overturned the notion that seawater only makes it about 100km into the mantle before it is returned to the Earth's surface through volcanic arcs, such as those forming the Pacific Ring of Fire that runs through the western America's, Japan and Tonga.

The team analysed samples of volcanic glass from the Atlantic, Pacific and Indian oceans that contained traces of seawater that had been deeply cycled throughout Earth's interior.

"The combination of water and halogens found in the volcanic glasses enables us to preclude local seawater contamination and conclusively prove the water in the samples was derived from the mantle," Dr Kendrick said.

Contacts and sources:
Will Wright
The Australian National University (ANU)

Citation: Seawater cycled throughout Earth’s mantle in partially serpentinized lithosphere http://dx.doi.org/10.1038/ngeo2902

Tuesday, February 28, 2017

Possible Change in Water ‘Fingerprint’ of Comet Lovejoy Detected by NASA

A trip past the sun may have selectively altered the production of one form of water in a comet - an effect not seen by astronomers before, a new NASA study suggests.

Astronomers from NASA's Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. Through NASA's partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion - or closest point to the sun.

The team focused on Lovejoy's water, simultaneously measuring the release of H2O along with production of a heavier form of water, HDO. Water molecules consist of two hydrogen atoms and one oxygen atom. A hydrogen atom has one proton, but when it also includes a neutron, that heavier hydrogen isotope is called deuterium, or the "D" in HDO. From these measurements, the researchers calculated the D-to-H ratio - a chemical fingerprint that provides clues about exactly where comets (or asteroids) formed within the cloud of material that surrounded the young sun in the early days of the solar system. Researchers also use the D-to-H value to try to understand how much of Earth's water may have come from comets versus asteroids.

Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun.
Credits: Courtesy of Damian Peach

The scientists compared their findings from the Keck observations with another team's observations made before the comet reached perihelion, using both space- and ground-based telescopes, and found an unexpected difference: After perihelion, the output of HDO was two to three times higher, while the output of H2O remained essentially constant. This meant that the D-to-H ratio was two to three times higher than the values reported earlier.

"The change we saw with this comet is surprising, and highlights the need for repeated measurements of D-to-H in comets at different positions in their orbits to understand all the implications," said Lucas Paganini, a researcher with the Goddard Center for Astrobiology and lead author of the study, available online in the Astrophysical Journal Letters.

Changes in the water production are expected as comets approach the sun, but previous understanding suggested that the release of these different forms of water normally rise or fall more-or-less together, maintaining a consistent D-to-H value. The new findings suggest this may not be the case.

"If the D-to-H value changes with time, it would be misleading to assume that comets contributed only a small fraction of Earth's water compared to asteroids," Paganini said, "especially, if these are based on a single measurement of the D-to-H value in cometary water."

The production of HDO in comets has historically been difficult to measure, because HDO is a much less abundant form of water. Lovejoy, for example, released on the order of 1,500 times more H2O than HDO. Lovejoy's brightness made it possible to measure HDO when the comet passed near Earth, and the improved detectors that are being installed in some ground-based telescopes will permit similar measurements in fainter comets in the future.

The apparent change in Lovejoy's D-to-H may be caused by the higher levels of energetic processes - such as radiation near the sun - that might have altered the characteristics of water in surface layers of the comet. In this case, a different D-to-H value might indicate that the comet has "aged" into a different stage of its lifecycle. Alternatively, prior results might have ignored possible chemical alteration occurring in the comet's tenuous atmosphere.

"Comets can be quite active and sometimes quite dynamic, especially when they are in the inner solar system, closer to the sun," said Michael Mumma, director of the Goddard Center for Astrobiology and a co-author of the study. "The infrared technique provides a snapshot of the comet's output by measuring the production of H2O and HDO simultaneously. This is especially important because it eliminates many sources of systematic uncertainty."

Contacts and sources:
Elizabeth Zubritsky
NASA's Goddard Space Flight Center

Surprising Discovery of Mayan Precious Jewel: “Like Finding the Hope Diamond in Peoria”

To say that UC San Diego archaeologist Geoffrey Braswell was surprised to discover a precious jewel in Nim Li Punit in southern Belize is something of an understatement.

"It was like finding the Hope Diamond in Peoria instead of New York," said Braswell, who led the dig that uncovered a large piece of carved jade once belonging to an ancient Maya king. "We would expect something like it in one of the big cities of the Maya world. Instead, here it was, far from the center," he said.

The jewel -- a jade pendant worn on a king's chest during key religious ceremonies -- was first unearthed in 2015. It is now housed at the Central Bank of Belize, along with other national treasures. 

The jade once belonging to an ancient Maya king is inscribed with 30 hieroglyphs. It was used during important religious ceremonies.

Courtesy G. Braswell/UC San Diego

Braswell recently published a paper in the Cambridge University journal Ancient Mesoamerica detailing the jewel's significance. A second paper, in the Journal of Field Archaeology, describes the excavations.

The pendant is remarkable for being the second largest Maya jade found in Belize to date, said Braswell, a professor in the Department of Anthropology at UC San Diego. The pendant measures 7.4 inches wide, 4.1 inches high and just 0.3 inches thick. Sawing it into this thin, flat form with string, fat and jade dust would have been a technical feat. But what makes the pendant even more remarkable, Braswell said, is that it's the only one known to be inscribed with a historical text. Carved into the pendant's back are 30 hieroglyphs about its first owner.

"It literally speaks to us," Braswell said. "The story it tells is a short but important one." He believes it may even change what we know about the Maya.

Also important: The pendant was "not torn out of history by looters," said Braswell. "To find it on a legal expedition, in context, gives us information about the site and the jewel that we couldn't have otherwise had or maybe even imagined."

Where the jewel was found

Nim Li Punit is a small site in the Toledo District of Belize. It sits on a ridge in the Maya Mountains, near the contemporary village of Indian Creek. Eight different types of parrot fly overhead. It rains nine months of the year.

The pendant was pictured on a carved image of a king at the site where it was unearthed.
Courtesy G. Braswell/UC San Diego

On the southeastern edge of the ancient Maya zone (more than 250 miles south of Chichen Itza in Mexico, where similar but smaller breast pieces have been found), Nim Li Punit is estimated to have been inhabited between A.D. 150 and 850. The site's name means "big hat." It was dubbed that, after its rediscovery in 1976, for the elaborate headdress sported by one of its stone figures. Its ancient name might be Wakam or Kawam, but this is not certain.

Braswell, UC San Diego graduate students Maya Azarova and Mario Borrero, along with a crew of local people, were excavating a palace built around the year 400 when they found a collapsed, but intact, tomb. Inside the tomb, which dates to about A.D. 800, were 25 pottery vessels, a large stone that had been flaked into the shape of a deity and the precious jade pectoral. Except for a couple of teeth, there were no human remains.

What was it doing there?

The pendant is in the shape of a T. Its front is carved with a T also. This is the Mayan glyph "ik'," which stands for "wind and breath." It was buried, Braswell said, in a curious, T-shaped platform. And one of the pots discovered with it, a vessel with a beaked face, probably depicts a Maya god of wind.

Wind was seen as vital by the Maya. It brought annual monsoon rains that made the crops grow. And Maya kings -- as divine rulers responsible for the weather -- performed rituals according to their sacred calendar, burning and scattering incense to bring on the wind and life-giving rains. According to the inscription on its back, Braswell said, the pendant was first used in A.D. 672 in just such a ritual.

Two relief sculptures on large rock slabs at Nim Li Punit also corroborate that use. In both sculptures, a king is shown wearing the T-shaped pendant while scattering incense, in A.D. 721 and 731, some 50 and 60 years after the pendant was first worn.

A stela from Nim Li Punit Maya site in what is now Belize

By the year 800, the pendant was buried, not with its human owner, it seems, but just with other objects. Why? The pendant wasn't a bauble, Braswell said, "it had immense power and magic." Could it have been buried as a dedication to the wind god? That's Braswell's educated hunch.

Maya kingdoms were collapsing throughout Belize and Guatemala around A.D. 800, Braswell said. Population levels plummeted. Within a generation of the construction of the tomb, Nim Li Punit itself was abandoned.

"A recent theory is that climate change caused droughts that led to the widespread failure of agriculture and the collapse of Maya civilization," Braswell said. "The dedication of this tomb at that time of crisis to the wind god who brings the annual rains lends support to this theory, and should remind us all about the danger of climate change."

The jade pendant was buried around A.D. 800 with other objects, including pottery and a large stone that had been flaked into the shape of a deity.
Courtesy G. Braswell/UC San Diego

Still and again: What was it doing there?

The inscription on the back of the pendant is perhaps the most intriguing thing about it, Braswell said. The text is still being analyzed by Braswell's coauthor on the Ancient Mesoamerica paper, Christian Prager of the University of Bonn. And Mayan script itself is not yet fully deciphered or agreed upon.

But Prager and Braswell's interpretation of the text so far is this: The jewel was made for the king Janaab' Ohl K'inich. In addition to noting the pendant's first use in A.D. 672 for an incense-scattering ceremony, the hieroglyphs describe the king's parentage. His mother, the text implies, was from Cahal Pech, a distant site in western Belize. The king's father died before aged 20 and may have come from somewhere in Guatemala.

It also describes the accession rites of the king in A.D. 647, Braswell said, and ends with a passage that possibly links the king to the powerful and immense Maya city of Caracol, located in modern-day Belize.

"It tells a political story far from Nim Li Punit," Braswell said. He notes that Cahal Pech, the mother's birthplace, for example, is 60 miles away. That's a five-hour bus ride today, and back then would have been many days' walk -- through rainforest and across mountains. How did the pendant come to this outpost?

While it's possible it had been stolen from an important place and whisked away to the provinces, Braswell doesn't think so. He believes the pendant is telling us about the arrival of royalty at Nim Li Punit, the founding of a new dynasty. The writing on the pendant is not particularly old by Maya standards, but it's the oldest found at Nim Li Punit so far, Braswell said. It's also only after the pendant's arrival that other hieroglyphs and images of royalty begin to show up on the site's stelae, or sculptured stone slabs.

It could be that king Janaab' Ohl K'inich himself moved to Nim Li Punit, Braswell said. Or it could be that a great Maya state was trying to ally with the provinces, expand its power or curry favor by presenting a local king with the jewel. Either way, Braswell believes, the writing on the pendant indicates ties that had been previously unknown.

"We didn't think we'd find royal, political connections to the north and the west of Nim Li Punit," said Braswell, who has been excavating in Belize since 2001 and at Nim Li Punit since 2010. "We thought if there were any at all that they'd be to the south and east."

Even if you ignore the writing and its apparent royal provenance, the jade stone itself is from the mountains of Guatemala, southwest of Belize. There are few earlier indications of trade in that direction either, Braswell said.

We may never know exactly why the pendant came to Nim Li Punit or why it was buried as it was, but Braswell's project to understand the site continues. He plans to return in the spring of 2017. This time, he also wants to see if he might discover a tie to the Caribbean Sea. After all, that's a mere 12 miles downriver, a four-hour trip by canoe.

Contacts and sources:
Inga Kiderra
University of California San Diego (UC San Diego)

The Oldest Fossil Giant Penguin Reveals Earlier Diversification

Together with colleagues from New Zealand, Senckenberg scientist Dr. Gerald Mayr described a recently discovered fossil of a giant penguin with a body length of around 150 centimeters.

The new find dates back to the Paleocene era and, with an age of approx. 61 million years, counts among the oldest penguin fossils in the world. The bones differ significantly from those of other discoveries of the same age and indicate that the diversity of Paleocene penguins was higher than previously assumed. In their study, published today in the Springer journal The Science of Nature, the team of scientists therefore postulates that the evolution of penguins started much earlier than previously thought, probably already during the age of dinosaurs.

The Waipara giant penguin compared to an Emperor Penguin (the largest extant penguin species) and a human.

Credit: Senckenberg Gesellschaft für Naturforschung (Senckenberg Nature Research Society)

The fossil sites along the Waipara River in New Zealand's Canterbury region are well known for their avian fossils, which were embedded in marine sand a mere 4 million years after the dinosaurs became extinct. "Among the finds from these sites, the skeletons of Waimanu, the oldest known penguin to date, are of particular importance," explains Dr. Gerald Mayr of the Senckenberg Research Institute in Frankfurt.

Together with colleagues from the Canterbury Museum in New Zealand, Mayr now described a newly discovered penguin fossil from the famous fossil site. "What sets this fossil apart are the obvious differences compared to the previously known penguin remains from this period of geological history," explains the ornithologist from Frankfurt, and he continues, "The leg bones we examined show that during its lifetime, the newly described penguin was significantly larger than its already described relatives. Moreover, it belongs to a species that is more closely related to penguins from later time periods."

According to the researchers, the newly described penguin lived about 61 million years ago and reached a body length of approx. 150 centimeters -- making it almost as big as Anthropornis nordenskjoeldi, the largest known fossil penguin, which lived in Antarctica around 45 to 33 million years ago, thus being much younger in geological terms. 

"This shows that penguins reached an enormous size quite early in their evolutionary history, around 60 million years ago," adds Mayr. In addition, the team of scientists from New Zealand and Germany assumes that the newly discovered penguin species also differed from their more primitive relatives in the genus Waimanu in their mode of locomotion: The large penguins presumably already moved with the upright, waddling gait characteristic for today's penguins.

"The discoveries show that penguin diversity in the early Paleocene was clearly higher than we previously assumed," says Mayr, and he adds, "In turn, this diversity indicates that the first representatives of penguins already arose during the age of dinosaurs, more than 65 million years ago."

Contacts and sources:
Melanie Lehnert

Mayr, G. et al. (2017). A new fossil from the mid-Paleocene of New Zealand reveals an unexpected diversity of world's oldest penguins, The Science of Nature.DOI 10.1007/s00114-017-1441-0   http://dx.doi.org/10.1007/s00114-017-1441-0 

Nanofiber Mesh Wrapping Promotes Nerve Regeneration

A NIMS-Osaka University joint research team developed a mesh which can be wrapped around injured peripheral nerves to facilitate their regeneration and restore their functions.

A research team consisting of Mitsuhiro Ebara, MANA associate principal investigator, Mechanobiology Group, NIMS, and Hiroyuki Tanaka, assistant professor, Orthopaedic Surgery, Osaka University Graduate School of Medicine, developed a mesh which can be wrapped around injured peripheral nerves to facilitate their regeneration and restore their functions. 

This mesh incorporates vitamin B12 -- a substance vital to the normal functioning of nervous systems -- which is very soft and degrades in the body. When the mesh was applied to injured sciatic nerves in rats, it promoted nerve regeneration and recovery of their motor and sensory functions. The team is currently considering clinical application of the mesh to treat peripheral nerve disorders such as carpal tunnel syndrome (CTS).

Conceptual diagram showing a nanofiber mesh incorporating vitamin B12 and its application to treat a peripheral nerve injury
Credit:  NIMS-Osaka University

Artificial nerve conduits have been developed in the past to treat peripheral nerve injuries, but they merely form a cross-link to the injury site and do not promote faster nerve regeneration. Moreover, their application is limited to relatively few patients suffering from a complete loss of nerve continuity. Vitamin B12 has been known to facilitate nerve regeneration, but oral administration of it has not proven to be very effective, and no devices capable of delivering vitamin B12 directly to affected sites had been available. Therefore, it had been hoped to develop such medical devices to actively promote nerve regeneration in the many patients who suffer from nerve injuries but have not lost nerve continuity.

The NIMS-Osaka University joint research team recently developed a special mesh that can be wrapped around an injured nerve which releases vitamin B12 (methylcobalamin) until the injury heals. By developing very fine mesh fibers (several hundred nanometers in diameter) and reducing the crystallinity of the fibers, the team successfully created a very soft mesh that can be wrapped around a nerve. This mesh is made of a biodegradable plastic which, when implanted in animals, is eventually eliminated from the body. In fact, experiments demonstrated that application of the mesh directly to injured sciatic nerves in rats resulted in regeneration of axons and recovery of motor and sensory functions within six weeks.

The team is currently negotiating with a pharmaceutical company and other organizations to jointly study clinical application of the mesh as a medical device to treat peripheral nerve disorders, such as CTS.

This study was supported by the JSPS KAKENHI program (Grant Number JP15K10405) and AMED’s Project for Japan Translational and Clinical Research Core Centers (also known as Translational Research Network Program).

This research was published online in the April 2017 issue of Acta Biomaterialia on February 5, 2017.

Contacts and sources:
National Institute for Materials Science (NIMS)

Citation: “Electrospun nanofiber sheets incorporating methylcobalamin promote nerve regeneration and functional recovery in a rat sciatic nerve crush injury model”; Koji Suzuki, Hiroyuki Tanaka, Mitsuhiro Ebara, Koichiro Uto, Hozo Matsuoka, Shunsuke Nishimoto, Kiyoshi Okada, Tsuyoshi Murase, and Hideki Yoshikawa; Acta Biomaterialia,http://dx.doi.org/10.1016/j.actbio.2017.02.004

Humans Cause More Wildfires Than Lightning, Longer Fire Season and Larger Fire Niche

A recent first-of-its-kind analysis of wildfire records over 20 years shows that human-started fires accounted for 84 percent of all wildfires, tripled the length of the fire season and dominated an area seven times greater than that affected by lightning-caused fires. Humans have "a remarkable influence" on modern U.S. wildfire regimes, they conclude.

Researchers co-led by Bethany Bradley at the University of Massachusetts Amherst and Jennifer Balch at the University of Colorado-Boulder report their findings in the current early online edition of Proceedings of the National Academy of Sciences.

They found that of the 1.5 million fires that required fire fighting between 1992-2012, human-caused fires accounted for almost half, 44 percent, of area burned. The researchers note that humans are expanding the "fire niche," a measure of ignition sources, fuel mass and dryness. Bradley explains, "Humans are expanding fires into more locations and environmental conditions than lightning is able to reach."

In an analysis of 20 years of wildfire records led by researchers at UMass Amherst and the University of Colorado-Boulder, they found human-started fires accounted for 84 percent of all wildfires, exhibiting 'a remarkable influence' on modern US wildfire regimes. Further, humans are expanding the fire niche into more locations and environments with historically low lightning-strike density.

Public domain. FEMA/Andrea Booher

"Humans create sufficient ignition pressure for wetter fuels to burn," the researchers say. "Human ignitions have expanded the fire niche into areas with historically low lightning strike density."

Bradley, Balch and colleagues suggest, "National and regional policy efforts to mitigate wildfire related hazards would benefit from focusing on reducing the human expansion of the fire niche." Further, they note that because the wildland-urban interface - houses intermingling with natural areas - is expected to double by 2030 from 9 percent of total U.S. land area now, "ignition pressure" and structure vulnerability will rise.

Bradley says, "It's generally pretty well known that people start a lot of fires; everything from campfires to burning yard waste to accidental fires in homes and other structures. But in the past, I used to think of 'wildfire' as a process that was primarily natural and driven by lightning. This analysis made me realize that human ignitions have an extraordinary impact on national fire regimes. From our analysis, we learned that human-started fires are amazingly common. We found that humans play a primary role in redistributing wildfires in space and over time."

Further, "It turns out that lightning-started fires happen primarily in the inter-mountain west and almost exclusively in the summer, whereas human-started fires happen pretty much everywhere and extend the fire season far into the spring and fall. Our paper is the first to document the remarkable influence of human ignitions on 'wildfire.' Since we humans are the source of most fires, we are also the solution to reducing the number of costly and damaging fires."

The research team, which included others from UMass Amherst, the Earth Lab and department of geography at the University of Colorado-Boulder and the University of Idaho, point out that "economic and ecological costs of wildfire in the United States have risen substantially in recent decades. While climate change has likely enabled a portion of the increase in wildfire activity, the direct role of people in increasing wildfire has been largely overlooked" until now.

Bradley says, "We saw significant increases in the numbers of large, human-started fires over time, especially in the spring. I think that's interesting, and scary, because it suggests that as spring seasons get warmer and earlier due to climate change, human ignitions are putting us at increasing risk of some of the largest, most damaging wildfires."

Balch says, "The hopeful news here is that we could, in theory, reduce human-started wildfires in the medium term. But at the same time, we also need to focus on living more sustainably with fire by shifting the human contribution to ignitions to more controlled, well-managed burns."

For this study, the researchers used the publicly available U.S. Forest Service's Fire Program Analysis-Fire-Occurrence Database, which includes federal, state and local wildfire records on public and private lands from 1992-2012. They did not include prescribed burns or agricultural fires. Earlier studies had focused only on the West, for example, or records from just one agency. Fire causes include arson, smoking, railroads, fireworks and children as well as campfires and burning debris.

To assess 20-year trends in human- vs. lightning-caused wildfires over time, they used only large fires that were independently verified by a multi-agency project providing consistent burn severity data and fire perimeter information to researchers and relevant agencies.

Contacts and sources:\
Daniel Fitzgibbons
University of Massachusetts Amherst

Newfound Primate Teeth Take a Bite Out of The Evolutionary Tree of Life

Fossil hunters have found part of an ancient primate jawbone related to lemurs -- the primitive primate group distantly connected to monkeys, apes and humans, a University of Southern California (USC) researcher said.

Biren Patel, an associate professor of clinical cell and neurobiology at the Keck School of Medicine of USC, has been digging for fossils in a paleontologically rich area of Kashmir in northern India for six years. Although paleontologists have scoured this region for a century, relics of small extinct primates were rarely found or studied.

Scientists named the new species Ramadapis sahnii and said that it existed 11 to 14 million years ago. It is a member of the ancient Sivaladapidae primate family, consumed leaves and was about the size of a house cat, said Patel, co-author of the new study in the Journal of Human Evolution.

The new species Ramadapis sahnii existed 11 to 14 million years ago and is a member of the ancient Sivaladapidae primate family. It consumed leaves and was about the size of a house cat.

Credit: Sheena Lad

"Among the primates, the most common ones in the Kashmir region are from a genus called Sivapithecus, which were ancestral forms of orangutans," Patel said. "The fossil we found is from a different group on the primate family tree -- one that is poorly known in Asia. We are filling an ecological and biogeographical gap that wasn't really well documented. Every little step adds to the understanding of our human family tree because we're also primates."

The last primate found in the area was 38 years ago. So, in addition to being a new species, this is the first primate fossil found in the area in decades.

"In the past, people were interested in searching for big things -- things they could show off to other people," Patel said. "A lot of the small fossils were not on their radar."

The inch-and-a-quarter partial mandible belongs to a primate weighing less than 11 pounds that had outlived its other adapidae cousins found in North America, Europe and Africa by millions of years.

"New primates are always a hot topic, and this one is the first of its kind from its area in Asia, which has significant consequences for understanding primate evolution in the Old World," said Michael Habib, an assistant professor of clinical cell and neurobiology at the Keck School of Medicine who was not involved in the study.

The question that remains is how the ecosystem in northern India supported this species when its relatives elsewhere were disappearing or had already gone extinct. Future fieldwork and recovering more fossil primates will help answer this question.

"People want to know about human origins, but to fully understand human origins, you need to understand all of primate origins, including the lemurs and these Sivaladapids," Patel said. "Lemurs and sivaladapids are sister groups to what we are -- the anthropoids -- and we are all primates."

Researchers from Hunter College of the City University of New York, New York Consortium in Evolutionary Primatology, Arizona State University, Stony Brook University and Panjab University also contributed to this study, which was supported by the Wenner-Gren Foundation, the American Association of Physical Anthropologists, the Institute of Human Origins and funding from some of the involved universities.

Contacts and sources:
Zen Vuong
University of Southern California (USC) 

Dogs, Toddlers Show Similarities in Social Intelligence

Most dog owners will tell you they consider their beloved pets to be members of their families. Now new research suggests that dogs may be even more like us than previously thought.

Evan MacLean, director of the Arizona Canine Cognition Center at the University of Arizona, found that dogs and 2-year-old children show similar patterns in social intelligence, much more so than human children and one of their closest relatives: chimpanzees. The findings, published in the journal Animal Behaviour (link to come), could help scientists better understand how humans evolved socially.

MacLean and his colleagues looked at how 2-year-olds, dogs and chimpanzees performed on comparable batteries of tests designed to measure various types of cognition. While chimps performed well on tests involving their physical environment and spatial reasoning, they did not do as well when it came to tests of cooperative communication skills, such as the ability to follow a pointing finger or human gaze.

Credit: Eduardo Merille/ Wikimedia Commons

Dogs and children similarly outperformed chimps on cooperative communication tasks, and researchers observed similar patterns of variation in performance between individual dogs and between individual children.

A growing body of research in the last decade has looked at what makes human psychology special, and scientists have said that the basic social communication skills that begin to develop around 9 months are what first seem to set humans apart from other species, said MacLean, assistant professor in the School of Anthropology in the UA College of Social and Behavioral Sciences.

"There's been a lot of research showing that you don't really find those same social skills in chimpanzees, but you do find them in dogs, so that suggested something superficially similar between dogs and kids," MacLean said. "The bigger, deeper question we wanted to explore is if that really is a superficial similarity or if there is a distinct kind of social intelligence that we see in both species.

"What we found is that there's this pattern, where dogs who are good at one of these social things tend to be good at lots of the related social things, and that's the same thing you find in kids, but you don't find it in chimpanzees," he said.

One explanation for the similarities between dogs and humans is that the two species may have evolved under similar pressures that favored "survival of the friendliest," with benefits and rewards for more cooperative social behavior.

"Our working hypothesis is that dogs and humans probably evolved some of these skills as a result of similar evolutionary processes, so probably some things that happened in human evolution were very similar to processes that happened in dog domestication," MacLean said. "So, potentially, by studying dogs and domestication we can learn something about human evolution."

The research could even have the potential to help researchers better understand human disabilities, such as autism, that may involve deficits in social skills, MacLean said.

Looking to dogs for help in understanding human evolution is a relatively new idea, since scientists most often turn to close human relatives such as chimpanzees, bonobos and gorillas for answers to evolutionary questions. Yet, it seems man's best friend may offer an important, if limited, piece of the puzzle.

"There are different kinds of intelligence, and the kind of intelligence that we think is very important to humans is social in nature, and that's the kind of intelligence that dogs have to an incredible extent," MacLean said. "But there are other aspects of cognition, like the way we reason about physical problems, where dogs are totally dissimilar to us. So we would never make the argument that dogs in general are a better model for the human mind -- it's really just this special set of social skills."

MacLean and his collaborators studied 552 dogs, including pet dogs, assistance-dogs-in-training and military explosive detection dogs, representing a variety of different breeds. The researchers assessed social cognition through game-based tests, in which they hid treats and toys and then communicated the hiding places through nonverbal cues such as pointing or looking in a certain direction. They compared the dogs' results to data on 105 2-year-old children who previously completed a similar cognitive test battery and 106 chimpanzees assessed at wildlife sanctuaries in Africa.

Contacts and sources:
Alexis Blue
University of Arizona

First Evidence of Rocky Planet Formation In Tatooine System

Evidence of planetary debris surrounding a double sun, ‘Tatooine-like’ system has been found for the first time by a UCL-led team of researchers.

Published today in Nature Astronomy and funded by the Science and Technology Facilities Council and the European Research Council, the study reports on the remains of shattered asteroids orbiting a double sun consisting of a white dwarf and a brown dwarf roughly 1000 light-years away in a system called SDSS 1557.

The discovery is remarkable because the debris appears to be rocky and suggests that terrestrial planets like Tatooine – Luke Skywalker’s home world in Star Wars – might exist in the system. To date, all exoplanets discovered in orbit around double stars are gas giants, similar to Jupiter, and are thought to form in the icy regions of their systems.

Credit: Mark Garlick, UCL, University of Warwick and University of Sheffield 

A disc of rocky debris from a disrupted planetesimal surrounds white dwarf plus brown dwarf binary star. The white dwarf is the burn-out core of a star that was probably similar to the Sun, the brown dwarf is only ~60 times heavier than Jupiter, and the two stars go around each other in only a bit over two hours.

In contrast to the carbon-rich icy material found in other double star systems, the planetary material identified in the SDSS 1557 system has a high metal content, including silicon and magnesium. These elements were identified as the debris flowed from its orbit onto the surface of the star, polluting it temporarily with at least 1017 g (or 1.1 trillion US tons) of matter, equating it to an asteroid at least 4 km in size.

Lead author, Dr Jay Farihi (UCL Physics & Astronomy), said: “Building rocky planets around two suns is a challenge because the gravity of both stars can push and pull tremendously, preventing bits of rock and dust from sticking together and growing into full-fledged planets. With the discovery of asteroid debris in the SDSS 1557 system, we see clear signatures of rocky planet assembly via large asteroids that formed, helping us understand how rocky exoplanets are made in double star systems."

In the Solar System, the asteroid belt contains the leftover building blocks for the terrestrial planets Mercury, Venus, Earth, and Mars, so planetary scientists study the asteroids to gain a better understanding of how rocky, and potentially habitable planets are formed. The same approach was used by the team to study the SDSS 1557 system as any planets within it cannot yet be detected directly but the debris is spread in a large belt around the double stars, which is a much larger target for analysis.

The discovery came as a complete surprise as the team assumed the dusty white dwarf was a single star but co-author Dr Steven Parsons (University of Valparaíso and University of Sheffield), an expert in double star (or binary) systems noticed the tell-tale signs. "We know of thousands of binaries similar to SDSS 1557 but this is the first time we've seen asteroid debris and pollution. The brown dwarf was effectively hidden by the dust until we looked with the right instrument", added Parsons, "but when we observed SDSS 1557 in detail we recognised the brown dwarf's subtle gravitational pull on the white dwarf."

The team studied the binary system and the chemical composition of the debris by measuring the absorption of different wavelengths of light or ‘spectra’, using the Gemini Observatory South telescope and the European Southern Observatory Very Large Telescope, both located in Chile.

Co-author Professor Boris Gänsicke (University of Warwick) analysed these data and found they all told a consistent and compelling story. "Any metals we see in the white dwarf will disappear within a few weeks, and sink down into the interior, unless the debris is continuously flowing onto the star. We'll be looking at SDSS 1557 next with Hubble, to conclusively show the dust is made of rock rather than ice."

Contacts and sources:
Rebecca Caygill
University College London (UCL)

Gang War Over Sex and Territory

Gang warfare is not unique to humans - banded mongooses do it too.

Now researchers from the University of Exeter have shed light on the causes of the fights - and found they are most common when females are receptive to breeding and when there is competition over food and territory.

The scientists, who studied a population of banded mongooses in Uganda, observed ferocious fighting between groups that often led to serious injury and even death.

During the conflicts, they saw individuals raiding dens and killing the pups of their neighbours, and males and females of rival groups mating with each other.

These are banded mongooses fighting.
Credit: Harry Marshall

"These fights are very chaotic, with 20 or 30 mongooses on each side arranged in battle lines," said lead author Dr Faye Thompson, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall.

"They all rush forward and fighting breaks out, with some individuals chasing each other into bushes - but at the same time males and females from opposing groups will sometimes mate with each other.

"The fighting is costly to both individuals and groups. Individuals are more likely to die and litters are less likely to survive to emergence if their group is involved in an aggressive encounter with a rival."

Banded mongooses
Credit: Feargus Cooney

Intriguingly, they discovered that pregnant females were less likely to lose their litters after such conflicts.

Dr Thompson added: "We found that females were significantly less likely to abort their litter if their group was involved in a fight with another group during gestation.

"This is a puzzling result, but one possible explanation is that unborn litters may be seen as particularly valuable during periods of conflict with rival groups.

"Pregnant females could be finding some way to maintain their pregnancy, perhaps to offset mortality from fighting and make their group bigger and more competitive in the future."

Banded mongooses rarely leave the group into which they are born, so group members are usually genetically related to one another. Fights between groups may provide an opportunity to avoid inbreeding.

Credit: Harry Marshall

As a result, males or females sometimes lead their group into enemy territory in search of unrelated mating partners.

Professor Michael Cant of the University of Exeter, who leads the long-term study of banded mongooses in Uganda, said: "Intergroup conflict can be very intense in social animals but has really only been studied in depth in humans and chimpanzees before now."

"Our results suggest that fighting between groups is one of the major forces promoting solidarity and cooperation within groups in these highly social mammals."

The paper, published in the journal Animal Behaviour, is entitled: "Causes and consequences of intergroup conflict in cooperative banded mongooses."

Contacts and sources:
Alex Morrison
University of Exeter

The Most Power-Packed Galaxies Even Found Evade Understanding

When the universe was young, a supermassive black hole -- bloated to the bursting point with stupendous power -- heaved out a jet of particle-infused energy that raced through the vastness of space at nearly the speed of light.

Billions of years later, a trio of Clemson University scientists, led by College of Science astrophysicist Marco Ajello, has identified this black hole and four others similar to it that range in age from 1.4 billion to 1.9 billion years old. These objects emit copious gamma rays, light of the highest energy, that are billions of times more energetic than light that is visible to the human eye.

The previously known earliest gamma-ray blazars -- a type of galaxy whose intense emission is powered by extremely powerful relativistic jets launched by monstrous black holes -- were more than 2 billion years old. Currently, the universe is estimated to be approximately 14 billion years old.

In the heart of an active galaxy, matter falling toward a supermassive black hole generates jets of particles traveling near the speed of light.
Credit: NASA's Goddard Space Flight Center
"The discovery of these supermassive black holes, which launch jets that emit more energy in one second than our sun will produce in its entire lifetime, was the culmination of a yearlong research project," said Ajello, who has spent much of his career studying the evolution of distant galaxies.
"Our next step is to increase our understanding of the mechanisms involved in the formation,

development and activities of these amazing objects, which are the most powerful accelerators in the universe. We can't even come close to replicating such massive outputs of energy in our laboratories. The complexities we're attempting to unravel seem almost as mysterious as the black holes themselves."

Ajello conducted his research in conjunction with Clemson post-doc Vaidehi Paliya and Ph.D candidate Lea Marcotulli. The trio worked closely with the Fermi-Large Area Telescope collaboration, which is an international team of scientists that includes Roopesh Ojha, an astronomer at NASA's Goddard Space Flight Center in Greenbelt, Maryland; and Dario Gasparrini of the Italian Space Agency. Their scientific paper titled "Gamma-Ray Blazars Within the First 2 Billion Years" was published Monday in a journal called Astrophysical Journal Letters. (Ackermann, M., et al. 2017, ApJL, 837, L5.)

The Clemson team's breakthroughs were made possible by recently juiced-up software on NASA's Fermi Gamma-ray Telescope. The refurbished software significantly boosted the orbiting telescope's sensitivity to a level that made these latest discoveries possible.

"People are calling it the cheapest refurbishment in history," Ajello said. "Normally, for the Hubble Space Telescope, NASA had to send someone up to space to physically make these kinds of improvements. But in this case, they were able to do it remotely from an Earth-bound location. And of equal importance, the improvements were retroactive, which meant that the previous six years of data were also entirely reprocessed. This helped provide us with the information we needed to complete the first step of our research and also to strive onward in the learning process."

Using Fermi data, Ajello and Paliya began with a catalog of 1.4 million quasars, which are galaxies that harbor at their centers active supermassive black holes. Over the course of a year, they narrowed their search to 1,100 objects. Of these, five were finally determined to be newly discovered gamma-ray blazars that were the farthest away - and youngest - ever identified.

"After using our filters and other devices, we were left with about 1,100 sources. And then we did the diagnostics for all of these and were able to narrow them down to 25 to 30 sources," Paliya said. "But we still had to confirm that what we had detected was scientifically authentic. So we performed a number of other simulations and were able to derive properties such as black hole mass and jet power. Ultimately, we confirmed that these five sources were guaranteed to be gamma-ray blazars, with the farthest one being about 1.4 billion years old from the beginning of time."

Marcotulli, who joined Ajello's group as a Ph.D student in 2016, has been studying the blazars' mechanisms by using images and data delivered from another orbiting NASA telescope, the Nuclear Spectroscopic Telescope Array (NuSTAR). At first, Marcotulli's role was to understand the emission mechanism of gamma-ray blazars closer to us. Now she is turning her attention toward the most distant objects in a quest to understand what makes them so powerful.

"We're trying to understand the full spectrum of the energy distribution of these objects by using physical models," Marcotulli said. "We are currently able to model what's happening far more accurately than previously devised, and eventually we'll be able to better understand what processes are occurring in the jets and which particles are radiating all the energy that we see. Are they electrons? Or protons? How are they interacting with surrounding photons? All these parameters are not fully understood right now. But every day we are deepening our understanding."

All galaxies have black holes at their centers - some actively feeding on the matter surrounding them, others lying relatively dormant. Our own galaxy has at its center a super-sized black hole that is currently dormant. Ajello said that only one of every 10 black holes in today's universe are active. But when the universe was much younger, it was closer to a 50-50 ratio.

The supermassive black holes at the center of the five newly discovered blazar galaxies are among the largest types of black holes ever observed, on the order of hundreds of thousands to billions of times the mass of our own sun. And their accompanying accretion disks - rotating swirls of matter that orbit the black holes - emit more than two trillion times the energy output of our sun.

One of the most surprising elements of Ajello's research is how quickly - by cosmic measures - these supersized black holes must have grown in only 1.4 billion years. In terms of our current knowledge of how black holes grow, 1.4 billion years is barely enough time for a black hole to reach the mass of the ones discovered by Ajello's team.

"How did these incomprehensibly enormous and energy-laden black holes form so quickly?" Ajello said. "Is it because one black hole ate a lot all the time for a very long time? Or maybe because it bumped into other black holes and merged into one? To be honest, we have no observations supporting either argument. There are mechanisms at work that we have yet to unravel. Puzzles that we have yet to solve. When we do eventually solve them, we will learn amazing things about how the universe was born, how it grew into what it has become, and what the distant future might hold as the universe continues to progress toward old age."

Contacts and sources:
Jim Melvin
Clemson University

Missing Link In Planet Formation: Astronomers Discover Spontaneous 'Dust Traps'

Planets are thought to form in the disks of dust and gas found around young stars. But astronomers have struggled to assemble a complete theory of their origin that explains how the initial dust develops into planetary systems. A French-UK-Australian team now think they have the answer, with their simulations showing the formation of 'dust traps' where pebble-sized fragments collect and stick together, to grow into the building blocks of planets. They publish their results in Monthly Notices of the Royal Astronomical Society.

Our Solar system, and other planetary systems, began life with disks of gas and dust grains around a young star. The processes that convert these tiny grains, each a few millionths of a metre (a micron) across, into aggregates a few centimetres in size, and the mechanism for making kilometre-sized 'planetesimals' into planetary cores, are both well understood.

An image of a protoplanetary disk, made using results from the new model, after the formation of a spontaneous dust trap, visible as a bright dust ring. Gas is depicted in blue and dust in red.

Credit: Jean-Francois Gonzalez

The intermediate stage, taking pebbles and joining them together into objects the size of asteroids, is less clear, but with more than 3,500 planets already found around other stars, the whole process must be ubiquitous.

Dr Jean-Francois Gonzalez, of the Centre de Recherche Astrophysique de Lyon, in France, led the new work. He comments: "Until now we have struggled to explain how pebbles can come together to form planets, and yet we've now discovered huge numbers of planets in orbit around other stars. That set us thinking about how to solve this mystery."

There are two main barriers that need to be overcome for pebbles to become planetesimals. Firstly the drag of gas on dust grains in a disk makes them drift rapidly towards the central star, where they are destroyed, leaving no material to form planets. The second challenge is that growing grains can be broken up in high-speed collisions, breaking them into a large number of smaller pieces and reversing the aggregation process.

This cartoon illustrates the stages of the formation mechanism for dust traps. The central star is depicted as yellow, surrounded by the protoplanetary disk, here shown in blue. The dust grains make up the band running through the disk.

In the first stage, the dust grains grown in size, and move inwards towards the central star. The now pebble-sized larger grains (in the second panel) then pile up and slow down, and in the third stage the gas is pushed outwards by the back-reaction, creating regions where dust accumulates, the so-called dust traps. The traps then allow the pebbles to aggregate to form planetesimals, and eventually planet-sized worlds.
Credit: © Volker Schurbert

The only locations in planet forming disks where these problems can be overcome are so-called 'dust traps'. In these high-pressure regions, the drift motion slows, allowing dust grains to accumulate. With their reduced velocity, the grains can also avoid fragmentation when they collide.

Until now, astronomers thought that dust traps could only exist in very specific environments, but the computer simulations run by the team indicate that they are very common. Their model pays particular attention to the way the dust in a disk drags on the gas component. In most astronomical simulations, gas causes the dust to move, but sometimes, in the dustiest settings, the dust acts more strongly on the gas.

This effect, known as aerodynamic drag back-reaction, is usually negligible, so up to now has been ignored in studies of growing and fragmenting grains. But its effects become important in dust rich environments, like those found where planets are forming.

The effect of the back-reaction is to slow the inward drift of the grains, which gives them time to grow in size. Once large enough, the grains are their own masters, and the gas can no longer govern their motion. The gas, under the influence of this back-reaction, will be pushed outwards and form a high-pressure region: the dust trap. These spontaneous traps then concentrate the grains coming from the outer disk regions, creating a very dense ring of solids, and giving a helping hand to the formation of planets.

Gonzalez concludes: "We were thrilled to discover that, with the right ingredients in place, dust traps can form spontaneously, in a wide range of environments. This is a simple and robust solution to a long standing problem in planet formation."

Observatories like ALMA in Chile already see bright and dark rings in forming planetary systems that are thought to be dust traps. Gonzalez and his team, and other research groups around the world, now plan to extend the trap model all the way to the formation of planetesimals.

Contacts and sources:
Dr Robert Massey
Royal Astronomical Society

Dr Jean-Francois Gonzalez
Centre de Recherche Astrophysique de Lyon
Observatoire de Lyon

The new work appears in "Self-induced dust traps: overcoming planet formation barriers", J.-F. Gonzalez, G. Laibe, and S. T. Maddison, Monthly Notices of the Royal Astronomical Society, in press. After the embargo expires the final paper will be available from OUP via http://doi.org/10.1093/mnras/stx016

Monday, February 27, 2017

Resurrecting Extinct Species: What Could Go Wrong?

Bringing back extinct species could lead to biodiversity loss rather than gain, according to work featuring University of Queensland researchers.

UQ scientist Professor Hugh Possingham said the research suggested further stretching already-strained conservation budgets to cover the costs of de-extinction could endanger extant species (species still in existence).

"If the risk of failure and the costs associated with establishing viable populations could also be calculated, estimates of potential net losses or missed opportunities would probably be considerably higher," Professor Possingham said.

"De-extinction could be useful for inspiring new science and could be beneficial for conservation if we ensure it doesn't reduce existing conservation resources.

This image shows a Lord Howe Island woodhen Gallirallus sylvestris.

Credit: Toby Hudson

"However, in general it is best if we focus on the many species that need our help now."

"Given the considerable potential for missed opportunity, and risks inherent in assuming a resurrected species would fulfil its role as an ecosystem engineer or flagship species, it is unlikely that de-extinction could be justified on grounds of biodiversity conservation."

The study was led by Dr Joseph Bennett, formerly of the ARC Centre for Environmental Decisions at UQ and now of Carleton University, Canada.

It analysed the number of species governments in New Zealand and New South Wales could afford to conserve.

"We based cost estimates on recently extinct species and similar extant species," Dr Bennett said.

The Lord Howe pigeon, eastern bettong, bush moa and Waitomo frog were among the extinct species included in calculations.

The researchers found reintroducing some recently extinct species to their old habitats might improve biodiversity locally, but government-funded conservation for 11 focal extinct species in New Zealand would sacrifice conservation for nearly three times as many (31) extant species.

External funding for conservation of the five focal extinct NSW species could instead be used to conserve more than eight times as many (42) extant species.

Although the technology for de-extinction is still some way off, the research found that careful thought would be required about what species to reintroduce, and where.

Professor Possingham is Chief Scientist with The Nature Conservancy, the world's largest conservation organisation, and a scientist with UQ's School of Biological Sciences, The Centre for Biodiversity and Conservation Science at UQ, the ARC Centre of Excellence for Environmental Decisions (CEED) and the Australian Government's National Environmental Science Program Threatened Species Recovery Hub.

Contacts and sources:
Hugh Possingham
University of Queensland 

The research is published in Nature Ecology and Evolution (DOI: 10.1038/s41559-016-0053). http://dx.doi.org/10.1038/s41559-016-0053

Getting Cyborg Cockroaches to Stay on Track: One Day They Will Explore Disaster Areas

New research from North Carolina State University offers insights into how far and how fast cyborg cockroaches - or biobots - move when exploring new spaces. The work moves researchers closer to their goal of using biobots to explore collapsed buildings and other spaces in order to identify survivors.

NC State researchers have developed cockroach biobots that can be remotely controlled and carry technology that may be used to map disaster areas and identify survivors in the wake of a calamity.

For this technology to become viable, the researchers needed to answer fundamental questions about how and where the biobots move in unfamiliar territory. Two forthcoming papers address those questions.

NC State researchers have found that by sending cockroach biobots random commands, the biobots spent more time moving, moved more quickly and were at least five times more likely to move away walls and into open space. The finding is a significant advance for developing biobots that can search collapsed buildings and other disaster areas for survivors.

Credit: Edgar Lobaton

The first paper answers questions about whether biobot technology can accurately determine how and whether biobots are moving.

The researchers followed biobot movements visually and compared their actual motion to the motion being reported by the biobot's inertial measurement units. The study found that the biobot technology was a reliable indicator of how the biobots were moving.

The second paper addresses bigger questions: How far will the biobots travel? How fast? Are biobots more efficient at exploring space when allowed to move without guidance? Or can remote-control commands expedite the process?

These questions are important because the answers could help researchers determine how many biobots they may need to introduce to an area in order to explore it effectively in a given amount of time.

For this study, researchers introduced biobots into a circular structure. Some biobots were allowed to move at will, while others were given random commands to move forward, left or right.

Credit: ARoS Lab

The researchers found that unguided biobots preferred to hug the wall of the circle. But by sending the biobots random commands, the biobots spent more time moving, moved more quickly and were at least five times more likely to move away from the wall and into open space.

"Our earlier studies had shown that we can use neural stimulation to control the direction of a roach and make it go from one point to another," says Alper Bozkurt, an associate professor of electrical and computer engineering at NC State and co-author of the two papers. "This [second] study shows that by randomly stimulating the roaches we can benefit from their natural walking and instincts to search an unknown area. Their electronic backpacks can initiate these pulses without us seeing where the roaches are and let them autonomously scan a region."

"This is practical information we can use to get biobots to explore a space more quickly," says Edgar Lobaton, an assistant professor of electrical and computer engineering at NC State and co-author on the two papers. "That's especially important when you consider that time is of the essence when you are trying to save lives after a disaster."

Lead author of the first paper, "A Study on Motion Mode Identification for Cyborg Roaches," is NC State Ph.D. student Jeremy Cole. The paper was co-authored by Ph.D. student Farrokh Mohammadzadeh, undergraduate Christopher Bollinger, former Ph.D. student Tahmid Latif, Bozkurt and Lobaton.

Lead author of the second paper, "Biobotic Motion and Behavior Analysis in Response to Directional Neurostimulation," is former NC State Ph.D. student Alireza Dirafzoon. The paper was co-authored by Latif, former Ph.D. student Fengyuan Gong, professor of electrical and computer engineering Mihail Sichitiu, Bozkurt and Lobaton.

Both papers will be presented at the 42nd IEEE International Conference on Acoustics, Speech and Signal Processing, being held March 5-9 in New Orleans.

Contacts and sources:
Matt Shipman
North Carolina State University