Quantum theory and Einstein's special relativity applied to plasma physics issues

This is a sketch of a pulsar, center, in binary star system.

Among the intriguing issues in plasma physics are those surrounding X-ray pulsars -- collapsed stars that orbit around a cosmic companion and beam light at regular intervals, like lighthouses in the sky. Physicists want to know the strength of the magnetic field and density of the plasma that surrounds these pulsars, which can be millions of times greater than the density of plasma in stars like the sun.

Researchers at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have developed a theory of plasma waves that can infer these properties in greater detail than in standard approaches. The new research analyzes the plasma surrounding the pulsar by coupling Einstein's theory of relativity with quantum mechanics, which describes the motion of subatomic particles such as the atomic nuclei -- or ions -- and electrons in plasma. Supporting this work is the DOE Office of Science.

Quantum field theory

The key insight comes from quantum field theory, which describes charged particles that are relativistic, meaning that they travel at near the speed of light. "Quantum theory can describe certain details of the propagation of waves in plasma," said Yuan Shi, a graduate student in the Princeton Program in Plasma Physics and lead author of a paper published July 29 in the journal Physical Review A. Understanding the interactions behind the propagation can then reveal the composition of the plasma.

Shi developed the paper with assistance from co-authors Nat Fisch, director of the Program in Plasma Physics and professor and associate chair of astrophysical sciences at Princeton University, and Hong Qin, a physicist at PPPL and executive dean of the School of Nuclear Science and Technology at the University of Science and Technology of China. "When I worked out the mathematics they showed me how to apply it," said Shi.

In pulsars, relativistic particles in the magnetosphere, the magnetized atmosphere that surrounds the body, absorb light waves, and this absorption displays peaks against a blackbody background. "The question is, what do these peaks mean?" asks Shi. Analysis of the peaks with equations from special relativity and quantum field theory, he found, can determine the density and field strength of the magnetosphere.

Combining physics techniques
The process combines the techniques of high-energy physics, condensed matter physics, and plasma physics. In high-energy physics, researchers use quantum field theory to describe the interaction of a handful of particles. In condensed matter physics, people use quantum mechanics to describe the states of a large collection of particles. Plasma physics uses model equations to explain the collective movement of millions of particles. The new method utilizes aspects of all three techniques to analyze the plasma waves in pulsars.

The same technique can be used to infer the density of the plasma and strength of the magnetic field created by inertial confinement fusion experiments. Such experiments use lasers to ablate -- or vaporize -- a target that contains plasma fuel. The ablation then causes an implosion that compresses the fuel into plasma and produces fusion reactions.

Read more at Science Daily

Gullies on Mars Probably Not Carved by Water

The gullies, three- to 33 feet in width, on a scarp in Mars' Hellas impact basin.

The hunt for what carved channels into polar-facing slopes on Mars -- a process that is ongoing today -- took a new twist on Friday with the release a study showing no chemical fingerprints of flowing water at more than 100 gully sites.

Similar features on Earth are carved by flowing liquid water. Mars' cold temperatures and a low atmospheric pressure means that liquid water would be transient, if it exists at all.

Nevertheless, telltale signs of water, in the form of hydrated salts, has been tied to another seasonal feature on Mars known as recurring slope lineae, or RSL.

Scientists are beginning to take test images of potential RSL sites in Gale Crater with NASA's Mars rover Curiosity, project scientist Ashwin Vasavada told DNews.

"These things really aren't understood yet," Vasavada said.

Scientists consider gullies to be features that have an alcove on top, a channel and an apron of material at the bottom. RSLs are characterized by seasonal darkening and fading, not how the ground is shaped.

Most RSLs are found on equator-facing slopes, as opposed to the pole-facing locations of gullies, leading scientists to theorize that the features stem from different processes.

Gullies are found all over Mars, with most located between 30 degrees and 50 degrees latitude in the northern and southern hemispheres.

In the new study, planetary scientist Jorge Nunez with Johns Hopkins University Applied Physics Laboratory, and colleagues correlated high-resolution images of more than 100 gullies taken by Mars Reconnaissance Orbiter with chemical data obtained by the spacecraft's Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM, instrument.

Several mechanisms have been proposed over the years to explain gully formation, including the melting of ground ice or the melting of a relict, regolith-covered snow pack. Another option is carbon dioxide frost activity that doesn't involve liquid water at all, the study said.

To help narrow the options, scientists looked for minerals, such as clays, silica, zeolites, sulfates, carbonates, or chlorides in the gullies which could indicate past water activity.

"We might have expected to see spectral evidence for liquid water such as hydrated salts as observed at RSL sites if present or recent liquid water activity had played a role in gully formation and evolution," the study said.

"We find no such evidence for brines in any of the gullies we have investigated," Nunez wrote.

The scientists conclude that their observations indicate "a limited role for long-lived liquid water in the formation and modification of Martian gullies, and support a stronger role for carbon dioxide frost-related processes."

The research is published in this week's Geophysical Research Letters.

Read more at Discovery News

Swirling data: Boosting computing power and info transfer rates tenfold

This is a close up look the vortex laser beam.

Like a whirlpool, a new light-based communication tool carries data in a swift, circular motion.

Described in a study published today (July 28, 2016) by the journal Science, the optics advancement could become a central component of next generation computers designed to handle society's growing demand for information sharing.

It may also be a salve to those fretting over the predicted end of Moore's Law, the idea that researchers will find new ways to continue making computers smaller, faster and cheaper.

"To transfer more data while using less energy, we need to rethink what's inside these machines," says Liang Feng, PhD, assistant professor in the Department of Electrical Engineering at the University at Buffalo's School of Engineering and Applied Sciences, and the study's co-lead author.

The other co-lead author is Natalia M. Litchinitser, PhD, professor of electrical engineering at UB.

Additional authors are: Pei Miao and Zhifeng Zhang, PhD candidates at UB; Jingbo Sun, PhD, assistant research professor of electrical engineering at UB; Wiktor Walasik, PhD, postdoctoral researcher at UB; and Stefano Longhi, PhD, professor at the Polytechnic University of Milan in Italy, and UB graduate students.

For decades, researchers have been able to cram evermore components onto silicon-based computer chips. Their success explains why today's smartphones have more computing power than the world's most powerful computers of the 1980s, which cost millions in today's dollars and were the size of a large file cabinet.

But researchers are running into a bottleneck in which existing technology may no longer meet society's demand for data. Predictions vary, but many suggest this could happen within the next five years.

Researchers are addressing the matter in numerous ways including optical communications, which uses light to carry information. Examples of optical communications vary from old lighthouses to modern fiber optic cables used to watch television and browse the internet.

Lasers are a central part of today's optical communication systems. Researchers have been manipulating lasers in various ways, most commonly by funneling different signals into one path, to carry more information. But these techniques -- specifically, wavelength-division multiplexing and time-division multiplexing -- are also reaching their limits.

The UB-led research team is pushing laser technology forward using another light manipulation technique called orbital angular momentum, which distributes the laser in a corkscrew pattern with a vortex at the center.

Usually too large to work on today's computers, the UB-led team was able to shrink the vortex laser to the point where it is compatible with computer chips. Because the laser beam travels in a corkscrew pattern, encoding information into different vortex twists, it's able to carry 10 times or more the amount of information than that of conventional lasers, which move linearly.

Read more at Science Daily

Tooth wear sheds light on the feeding habits of ancient elephant relatives

Elephant tusks

How can we ever know what ancient animals ate? For the first time, the changing diets of elephants in the last two million years in China have been reconstructed, using a technique based on analysis of the surface textures of their teeth.

The work was carried out by a University of Bristol student, working with an international team of researchers. The research was published online in Quaternary International.

Today, elephants live only in remote, tropical parts of Africa and southern Asia, but before the Ice Ages they were widespread.

As his undergraduate research project, Zhang Hanwen, MSci Palaeontology and Evolution graduate and now PhD student at the University of Bristol, undertook cutting-edge analysis of fossilised elephant teeth from China.

In a collaboration with the University of Leicester, and the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, where the fossilised teeth are curated, Hanwen sampled 27 teeth for tiny wear patterns called microwear.

"We are talking huge, brick-sized molars here -- the largest of any animal," said Hanwen, "but the signs of tooth wear are tiny, down to thousandths of a millimetre. However, these microscopic surface textures can tell us whether they were eating grass or leaves."

Hanwen took peels of the fossilised teeth in China, using high-grade dental moulding materials, and captured the 3D surface textures under a digital microscope at the University of Leicester. The textures were quantified and analysed to identify what the elephants were eating in the days and weeks before they died.

By comparing the results with information from modern ruminants (deer, antelopes and oxen) of known diet, the study concluded two extinct elephants from Southern China -- Sinomastodon and Stegodon -- were primarily browsing on leaves. The third, Elephas, which includes the modern Asian elephants, shows much more catholic feeding habit, incorporating both grazing and browsing.

"It's wonderful that we can identify diets of any fossil mammal with confidence now," said Professor Christine Janis, from the University of Bristol, one of Hanwen's PhD supervisors and a leading expert on the evolution of herbivorous mammals.

"This is based on the fact that the microwear textures produced by different kinds of plant material are comparable across unrelated animals."

"This method for identifying diet relies on high-quality 3D surface data and analysis," said Professor Mark Purnell, of the University of Leicester, another co-supervisor of Hanwen's.

"It removes the subjectivity of trying to quantify microwear textures by identifying and counting scratches and pits in 2D microscopic images."

Sinomastodon and Stegodon coexisted in Southern China between 2.6 and one million years ago, but Sinomastodon then became extinct and left Stegodon to become the dominant elephant of Southern China for the remainder of the Pleistocene, the time of the great Ice Ages.

"The fossil pollen record, and recently-excavated mammal fossil assemblages from various karst cave sites near the Chinese-Vietnamese border, suggest a prolonged, fluctuating period of environmental deterioration around this time," Hanwen explained.

He added: "Forests were on the decline, alongside many of the more archaic mammal species that inhabited them. The highly evolved molars of Stegodon, with multiple enamel ridges, might have allowed it to browse on its preferred foliage in a more efficient way, thus outcompeting Sinomastodon, which preferred the same diet, but had less sophisticated molars consisting of large, blunt, conical cusps."

Read more at Science Daily

Teasing out the microbiome of the Kansas prairie

Scientists at the Pacific Northwest National Laboratory have untangled that Kansas-based mess of microbes more fully than scientists have ever done for a sample of soil.

The Kansas prairie seems like the very picture of beauty and simplicity, with undulating fields of corn and wheat stretching as far as the eye can see.

But below ground, the soil bears witness to the incredible diversity and chaos of life within even the smallest patch of ground. Just a teaspoonful of Kansas soil contains tens of thousands of microbial species.

Now scientists at the Pacific Northwest National Laboratory have untangled that Kansas-based mess of microbes more fully than scientists have ever done for a sample of soil.

In one of the most in-depth looks to date at a soil metagenome -- all the genetic material recovered from a sample of soil -- the team reconstructed portions of the genomes of 129 species of microbes. While it's only a tiny proportion of the estimated 100,000 species in the sample, it's a leap forward for scientists who have had only a fraction of that success to date.

The results include the first reconstruction of the complete genome of a single microbe ever from a complex soil sample. Other groups have reconstructed full genomes of microbes out of less complex environments, including mines, microbial mats, and the human microbiome.

The results were published recently in mSystems, a publication of the American Society for Microbiology.

Soil microbes: Crucial for climate, environment

Microbes in soil determine in large part how the planet stores carbon, when and how carbon is released into the environment, how plants take up nutrients and how crops fare. While many people have become familiar with the community of microbes that live on us, with us, and within us -- the human microbiome -- the soil microbiome is lesser known but crucial for the fate of our planet. More knowledge about microbes helps scientists understand climate change and the forces that shape the health of our planet.

While scientists have made strides sorting out which species are present in complex soil samples, how those species interact remains a hugely daunting problem.

"We're trying to sort out the broad questions. What are the various microbes in the microbial community doing? Which species are very active and which seem dormant? How do they all fit together?" said microbiologist Janet Jansson, the corresponding author.

"Today we're able to compile immense data about microbial communities very quickly, but it's very difficult to put the information together to create a coherent picture," she added.

Jansson turned to post-doctoral associate Richard Allen White III, the first author of the paper, to take on the challenge of disentangling the genomes.

Digging up the dirt on the Kansas prairie

The team started with data culled from a sample of uncultivated, native Kansas prairie collected at the Konza Prairie Biological Station in northeastern Kansas. Scientists compiled the genetic data previously through the Great Prairie Soil Metagenome Grand Challenge Initiative at the Joint Genome Institute, a DOE Office of Science User Facility.

The Kansas soil is from the Great Plains, where soil has high carbon content compared to other soils. Scientists like Jansson are exploring what will happen in the soil as the climate changes. For example, there could be greater release of greenhouse gases to the atmosphere if microorganisms convert carbon to carbon dioxide more rapidly.

The sample under scrutiny included more than 250 billion base pairs of genetic data, mostly of microbes, which awaited a scientific team with the chutzpah to try to make sense of it. Jansson's team took on the challenge, unraveling an amount of information approximately equal to all the data streaming through 200 cell phones in a month.

The genetic material didn't come neatly packaged. It had been torn, split, twisted, crushed and exposed to all manner of disrespect.

"Imagine taking a thick book written in hundreds of different languages, chopping the book up into pieces the size of grains of rice, and then having to put it back together again," said White. "That's not unlike the challenge we face when we try to understand what's going on in even a handful of soil."

Jansson considers untangling the microbes in soil especially challenging because there is a huge diversity. Scientists estimate 50 to 100 times as many microbial species inhabit a typical soil sample than the human gut. Also, most microbes from soil have never been grown in a laboratory where they could be studied thoroughly.

Knitting soil DNA together

Scientists use multiple techniques to knit together strings of DNA accurately. The techniques are generally a combination of sophisticated chemistry methods and software algorithms designed to make sense of genetic material. A key to the team's success was the use of powerful supercomputers at PNNL and EMSL, the Environmental Molecular Sciences Laboratory. EMSL is a DOE Office of Science User Facility on the PNNL campus.

To do the study, White used a sequencing technology originally developed in the laboratory of his former adviser, Stephen Quake of Stanford. Scientists use the genome analysis tool to break DNA down into smaller pieces, then sequence those and assemble those into longer pieces.

When the team combined the technology with other methods, they ended up with 10,000 pieces of DNA, each longer than 10 kilobase pairs -- longer than 10,000 pairs of the biological compounds that make up DNA. Other attempts at cracking a soil metagenome have yielded much lower numbers, for instance, just 9 pieces of DNA of that length -- less than one-thousandth of what the team achieved.

Read more at Science Daily

New fossil evidence supports theory that first mass extinction engineered by early animals

Conichnus burrows are trace fossils: the surface bumps represent vertical tubes that were originally occupied by anemone-like animals that may have fed on Ediacaran larvae.

Newly discovered fossil evidence from Namibia strengthens the proposition that the world's first mass extinction was caused by "ecosystem engineers" -- newly evolved biological organisms that altered the environment so radically it drove older species to extinction.

The event, known as the end-Ediacaran extinction, took place 540 million years ago. The earliest life on Earth consisted of microbes -- various types of single-celled organisms. These held sway for more than 3 billion years, when the first multicellular organisms evolved. The most successful of these were the Ediacarans, which spread around the globe about 600 million years ago. They were a largely immobile form of marine life shaped like discs and tubes, fronds and quilted mattresses.

After 60 million years, evolution gave birth to another major innovation: metazoans, the first animals. Metazoans could move spontaneously and independently at least during some point in their life cycle and sustain themselves by eating other organisms or what other organisms produce. Animals burst onto the scene in a frenzy of diversification that paleontologists have labeled the Cambrian explosion, a 25 million-year period when most of the modern animal families -- vertebrates, mollusks, arthropods, annelids, sponges and jellyfish -- came into being.

"These new species were 'ecological engineers' who changed the environment in ways that made it more and more difficult for the Ediacarans to survive," said Simon Darroch, assistant professor of earth and environmental sciences at Vanderbilt University, who directed the new study described in the paper titled "A mixed Ediacaran-metazoan assemblage from the Zaris Sub-basin, Namibia," published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

Darroch and his colleagues report that they have found one of the best-preserved examples of a mixed community of Ediacarans and animals, which provides the best evidence of a close ecological association between the two groups.

"Until this, the evidence for an overlapping ecological association between metazoans and soft-bodied Ediacaran organisms was limited," Darroch said. "Here, we describe new fossil localities from southern Namibia that preserve soft-bodied Ediacara biota, enigmatic tubular organisms thought to represent metazoans and vertically oriented metazoan trace fossils. Although the precise identity of the tracemakers remains elusive, the structures bear several striking similarities with a cone-shaped organism called Conichnus that has been found in the Cambrian period."

In a previous paper that Darroch and his collaborators published last September, they reported on a fossil record that showed stressed-looking communities of Ediacara associated with a suite of animal burrows.

"With this paper we're narrowing in on causation; we've discovered some new fossil sites that preserve both Ediacara biota and animal fossils (both animal burrows -- 'trace fossils' -- and the remains of animals themselves) sharing the same communities, which lets us speculate about how these two very different groups of organisms interacted," he said.

"Some of the burrow fossils we've found are usually interpreted as being formed by sea anemones, which are passive predators that may have preyed upon Ediacaran larvae. We've also found stands of Ediacaran frondose organisms, with animal fossils preserved in place coiled around their bases. In general, these new fossil sites reveal a snapshot of a very unusual 'transitional' ecosystem existing right before the Cambrian explosion, with the last of the Ediacara biota clinging on for grim death, just as modern-looking animals are diversifying and starting to realize their potential."

Read more at Science Daily

Cancer on a Paleo-diet? Ask someone who lived 1.7 million years ago

Metatarsal (a) and (b) surface rendered models show medullary spongy bone infill and clear focalized cortical destruction near the periosteal margin; also evident on external cortical margin directly abutting malignant neoplasm is the characteristic hair on end bone reaction in (b).

An international team of researchers led by scientists from the University of the Witwatersrand's Evolutionary Studies Institute and the South African Centre for Excellence in PalaeoSciences today announced in two papers, published in the South African Journal of Science, the discovery of the most ancient evidence for cancer and bony tumors yet described in the human fossil record.

The discovery of a foot bone dated to approximately 1.7 million years ago from the site of Swartkrans with definitive evidence of malignant cancer, pushes the oldest date for this disease back from recent times into deep prehistory. Although the exact species to which the foot bone belongs is unknown, it is clearly that of a hominin, or bipedal human relative.

In an accompanying paper appearing in the same journal, a collaborating team of scientists identify the oldest tumor ever found in the human fossil record, a benign neoplasm found in the vertebrae of the well-known Australopithecus sediba child, Karabo from the site of Malapa, and dated to almost two million years in age. The oldest previously demonstrated possible hominin tumor was found in the rib of a Neanderthal and dated to around 120,000 years old.

Edward Odes, a Wits doctoral candidate and lead author of the cancer paper, and co-author on the tumor paper, notes "Modern medicine tends to assume that cancers and tumors in humans are diseases caused by modern lifestyles and environments. Our studies show the origins of these diseases occurred in our ancient relatives millions of years before modern industrial societies existed."

The cancer in a foot bone, a metatarsal, was identified as an osteosarcoma, an aggressive form of cancer which usually affects younger individuals in modern humans, and, if untreated typically results in early death. "Due to its preservation, we don't know whether the single cancerous foot bone belongs to an adult or child, nor whether the cancer caused the death of this individual, but we can tell this would have affected the individuals' ability to walk or run," says Dr Bernhard Zipfel, a Wits scientist and an expert on the foot and locomotion of early human relatives. "In short, it would have been painful."

Lead author of the tumor paper and co-author of the cancer paper, Dr Patrick Randolph-Quinney of Wits University and the University of Central Lancashire in the UK, suggests "The presence of a benign tumor in Australopithecus sediba is fascinating not only because it is found in the back, an extremely rare place for such a disease to manifest in modern humans, but also because it is found in a child. This, in fact, is the first evidence of such a disease in a young individual in the whole of the fossil human record."

Prof. Lee Berger, an author on both papers and leader of the Malapa project where the fossil vertebra was found adds "not only has there been an assumption that these sorts of cancers and tumors are diseases of modernity, which these fossils clearly demonstrate they are not, but that we as modern humans exhibit them as a consequence of living longer, yet this rare tumor is found in a young child. The history of these types of tumors and cancers is clearly more complex than previously thought."

Both incidents of disease were diagnosed using state of the art imaging technologies including those at the European Synchrotron Research Facility in Grenoble, France, medical CT at the Charlotte Maxeke Hospital in Johannesburg, and the micro-CT facility at the Nuclear Energy Corporation of South Africa at Pelindaba.

Read more at Science Daily

World's Deepest Blue Hole Is in South China Sea

A new exploration of a legendary blue hole in the South China Sea has found that the underwater feature is the deepest known on Earth.

According to Xinhua News, Dragon Hole, or Longdong, is 987 feet (300.89 meters) deep, far deeper than the previous record holder, Dean's Blue Hole in the Bahamas. (That blue hole measures about 663 feet, or 202 m, deep.) According to Xinhua, local legend holds that Dragon Hole is mentioned in the Ming dynasty novel "Journey to the West," in which a supernatural monkey character gets a magical cudgel from an undersea kingdom ruled by a dragon.

The findings have yet to be confirmed or reviewed by scientists in the field, but if they hold up, the measurements peg Dragon Hole as far deeper than Dean's Blue Hole, said Pete van Hengstum, a marine geologist at Texas A&M University at Galveston, who conducts research on blue holes and sinkholes throughout the Caribbean region.

Blue holes are water-filled sinkholes that form in carbonate rock such as limestone. Over long periods of time, the carbonate rock dissolves in the subsurface to form caves or cavities, van Hengstum told Live Science.

"Eventually, the process of dissolution causes the cave to reach very close to the Earth's surface, and if the cave ceiling collapses, a blue hole or sinkhole is formed," he said.

Some blue holes, like Dragon Hole, open up to the marine environment, while others are inland.

It's something of a mystery why blue holes form precisely where they do and what factors influence their development. Chemical reactions at the interface of saltwater and freshwater can create weak acids that eat away at limestone and other carbonates, said Lisa Park Boush, a geoscientist at the University of Connecticut who studies blue-hole sediments in the Bahamas. As a result, rising and falling sea levels can influence when and where blue holes form.

"There is also a group of researchers looking into microbial processes," Boush told Live Science. In some cases, she said, microbe activity might help to dissolve bedrock and contribute to the formation of blue holes.

In addition to microbes, other organisms also call these jaw-droppingly gorgeous holes home.

"It's interesting to see what actually lives in these blue holes," said Boush, who called the environment of blue holes "cryptic."

Scientists with the Sansha Ship Course Research Institute for Coral Protection in China used an underwater robot and a depth sensor to investigate the mysterious environment of Dragon Hole, which is a well-known feature in Yongle, a coral reef near the Xisha Islands in the South China Sea, according to Xinhua. They found more than 20 marine organisms living in the upper portions of the hole. Below about 328 feet (100 m), the seawater in the blue hole had almost no oxygen, and thus little life, the researchers told Xinhua on July 22.

Even so, diving in blue holes is extremely dangerous, she said.

"One of the reasons why it's very dangerous is because of the limited oxygen," she said. "And sometimes there are even sulfuric waters."

Well-trained divers can make the journey, van Hengstum said. In other cases, researchers park a boat right above a blue hole and send equipment down to measure depth, temperature, oxygenation and other factors. Both Boush and van Hengstum conduct research on the sediments at the bottom of blue holes. These sediments contain information about the past environment and climate change — and sometimes fossils.

Read more at Discovery News

Mysterious 'Purple Blob' Spotted Off California Coast

A mysterious "purple blob" in the Pacific Ocean off of California's southern coast was spotted this week by Ocean Exploration Trust's vessel, Nautilus.

The as-of-yet unidentified purple orb could represent a previously unknown type of egg sac or a new species, according to researchers aboard the vessel, which has been streaming live footage. The moment of discovery, complete with the scientists' comments and a curious crab, was captured in full on video:

As the video shows, the colorful orb was sucked into the vessel. Shortly thereafter, Nautilus Live shared via social media that the find was collected from the Arguello Canyon near the NOAA Channel Islands National Marine Sanctuary.

"After sampling," the statement reads, "it began to unfold to reveal two distinct lobes. This may be a new species of nudibranch, or sea slug."

Several hours later, this update was posted: "We're still working on a species ID with our science partners, but currently we're thinking the purple orb is a pleurobranch, a nudibranch relative."

Pleurobranchs are a type of sea slug that have a prominent outer covering called a mantle and an internal shell that reduces, or is entirely lost, in adults. Pleurobranchs often visually stand out from the substrate.

Pleurobranchus forskali.

As researchers further analyze the still mysterious orb, Nautilus has continued its exploration of waters off the southern California coast. A short while ago, the scientists posted the following image saying: "From mysterious purple orbs to this crinoid on a column of whelk snail eggs, we never know what we'll find on the deep sea floor!"

Read more at Discovery News

'Game of Thrones' Spiked Ants Discovered

3-D scan of the newly discovered ant Pheidole drogon.

The dragons Viserion and Drogon from the "Game of Thrones" fantasy novels and TV series have come to life in miniature as two newly discovered muscular, spiny ants, which are described in a new study.

The new ants, Pheidole viserion and Pheidole drogon, not only feature dragon-like characteristics, but the soldier ants of these species also have massive heads relative to the size of the rest of their bodies. The formidable insects are documented in the journal PLOS ONE.

3-D scans of a Pheidole drogon minor (left) and a major worker (right).

Researchers Georg Fischer, Eli Sarnat and Evan Economo from the Okinawa Institute of Science and Technology Graduate University found the ants in the tropical rainforests of Papua New Guinea. To study the ants, they used a cutting edge 3-D imaging technology called x-ray microtomography, which is like a hospital CT scan, but with a much higher resolution suitable for small organisms.

"This is one of the first studies in ant taxonomy to use micro-CT," Economo, head of OIST's Biodiversity and Biocomplexity Unit, said in a press release. "While this method is gaining popularity in different scientific fields, it is rare to use it in this way."

Pheidole viserion.

Fischer said, "If you are working in the bush in Africa and find an ant that you want to identify, it is really difficult to fly all the way to a museum in Europe or the U.S. to see collections of already known species. This way you can download the virtual ant, make measurements, and compare it to the specimen you are trying to identify."

That process, along with more traditional analysis, allowed the researchers to determine that the found ants represent new species. The ants now "live" in 3-D, allowing them to be dissected, archived and shared with other scientists around the world.

The spines on the ants help to protect the insects, but the scientists think the sharp appendages serve another surprising function, given the ants' enormous heads.

"Once you open up the rotational 3-D PDF and see these ants' extraordinary spines, or 'inordinate spinescence' as we phrase it in the study, you can't help but ask why on earth these structures evolved," Sarnat said. "The most obvious answer is defense, but the internal morphology revealed by this new micro-CT scanning technology suggests that the answer might also have something to do with muscle mechanics and powering the huge heads of the soldier ants."

Read more at Discovery News