Nov 26, 2015

'Material universe' yields surprising new particle

An international team of researchers has predicted the existence of a new type of particle called the type-II Weyl fermion in metallic materials. When subjected to a magnetic field, the materials containing the particle act as insulators for current applied in some directions and as conductors for current applied in other directions. This behavior suggests a range of potential applications, from low-energy devices to efficient transistors.

The researchers theorize that the particle exists in a material known as tungsten ditelluride (WTe2), which the researchers liken to a "material universe" because it contains several particles, some of which exist under normal conditions in our universe and others that may exist only in these specialized types of crystals. The research appeared in the journal Nature this week.

The new particle is a cousin of the Weyl fermion, one of the particles in standard quantum field theory. However, the type-II particle exhibits very different responses to electromagnetic fields, being a near perfect conductor in some directions of the field and an insulator in others.

The research was led by Princeton University Associate Professor of Physics B. Andrei Bernevig, as well as Matthias Troyer and Alexey Soluyanov of ETH Zurich, and Xi Dai of the Chinese Academy of Sciences Institute of Physics. The team included Postdoctoral Research Associates Zhijun Wang at Princeton and QuanSheng Wu at ETH Zurich, and graduate student Dominik Gresch at ETH Zurich.

The particle's existence was missed by physicist Hermann Weyl during the initial development of quantum theory 85 years ago, say the researchers, because it violated a fundamental rule, called Lorentz symmetry, that does not apply in the materials where the new type of fermion arises.

Particles in our universe are described by relativistic quantum field theory, which combines quantum mechanics with Einstein's theory of relativity. Under this theory, solids are formed of atoms that consist of a nuclei surrounded by electrons. Because of the sheer number of electrons interacting with each other, it is not possible to solve exactly the problem of many-electron motion in solids using quantum mechanical theory.

Instead, our current knowledge of materials is derived from a simplified perspective where electrons in solids are described in terms of special non-interacting particles, called quasiparticles, that move in the effective field created by charged entities called ions and electrons. These quasiparticles, dubbed Bloch electrons, are also fermions.

Just as electrons are elementary particles in our universe, Bloch electrons can be considered the elementary particles of a solid. In other words, the crystal itself becomes a "universe," with its own elementary particles.

In recent years, researchers have discovered that such a "material universe" can host all other particles of relativistic quantum field theory. Three of these quasiparticles, the Dirac, Majorana, and Weyl fermions, were discovered in such materials, despite the fact that the latter two had long been elusive in experiments, opening the path to simulate certain predictions of quantum field theory in relatively inexpensive and small-scale experiments carried out in these "condensed matter" crystals.

These crystals can be grown in the laboratory, so experiments can be done to look for the newly predicted fermion in WTe2 and another candidate material, molybdenum ditelluride (MoTe2).

"One's imagination can go further and wonder whether particles that are unknown to relativistic quantum field theory can arise in condensed matter," said Bernevig. There is reason to believe they can, according to the researchers.

The universe described by quantum field theory is subject to the stringent constraint of a certain rule-set, or symmetry, known as Lorentz symmetry, which is characteristic of high-energy particles. However, Lorentz symmetry does not apply in condensed matter because typical electron velocities in solids are very small compared to the speed of light, making condensed matter physics an inherently low-energy theory.

"One may wonder," Soluyanov said, "if it is possible that some material universes host non-relativistic 'elementary' particles that are not Lorentz-symmetric?"

This question was answered positively by the work of the international collaboration. The work started when Soluyanov and Dai were visiting Bernevig in Princeton in November 2014 and the discussion turned to strange unexpected behavior of certain metals in magnetic fields (Nature 514, 205-208, 2014, doi:10.1038/nature13763). This behavior had already been observed by experimentalists in some materials, but more work is needed to confirm it is linked to the new particle.

The researchers found that while relativistic theory only allows a single species of Weyl fermions to exist, in condensed matter solids two physically distinct Weyl fermions are possible. The standard type-I Weyl fermion has only two possible states in which it can reside at zero energy, similar to the states of an electron which can be either spin-up or spin-down. As such, the density of states at zero energy is zero, and the fermion is immune to many interesting thermodynamic effects. This Weyl fermion exists in relativistic field theory, and is the only one allowed if Lorentz invariance is preserved.

The newly predicted type-2 Weyl fermion has a thermodynamic number of states in which it can reside at zero energy -- it has what is called a Fermi surface. Its Fermi surface is exotic, in that it appears along with touching points between electron and hole pockets. This endows the new fermion with a scale, a finite density of states, which breaks Lorentz symmetry.

The discovery opens many new directions. Most normal metals exhibit an increase in resistivity when subject to magnetic fields, a known effect used in many current technologies. The recent prediction and experimental realization of standard type-I Weyl fermions in semimetals by two groups in Princeton and one group in IOP Beijing showed that the resistivity can actually decrease if the electric field is applied in the same direction as the magnetic field, an effect called negative longitudinal magnetoresistance. The new work shows that materials hosting a type-II Weyl fermion have mixed behavior: While for some directions of magnetic fields the resistivity increases just like in normal metals, for other directions of the fields, the resistivity can decrease like in the Weyl semimetals, offering possible technological applications.

Read more at Science Daily

Sensor sees nerve action as it happens

Researchers at Duke and Stanford Universities have devised a way to watch the details of neurons at work, pretty much in real time.

Every second of every day, the 100 billion neurons in your brain are capable of firing off a burst of electricity called an action potential up to 100 times per second. For neurologists trying to study how this overwhelming amount of activity across an entire brain translates into specific thoughts and behaviors, they need a faster way to watch.

Existing techniques for monitoring neurons are too slow or too tightly focused to generate a holistic view. But in a new study, researchers reveal a technique for watching the brain's neurons in action with a time resolution of about 0.2 milliseconds -- a speed just fast enough to capture the action potentials in mammalian brains.

The paper appeared early online in Science.

"We set out to combine a protein that can quickly sense neural voltage potentials with another protein that can amplify its signal output," said Yiyang Gong, assistant professor of biomedical engineering at Duke and first author on the paper. "The resulting increase in sensor speed matches what is needed to read out electrical spikes in the brains of live animals."

Gong did the work as a postdoctoral fellow in the laboratory of Mark Schnitzer, associate professor of biological sciences and applied physics at Stanford, and an investigator of the Howard Hughes Medical Institute. Gong and his colleagues sought out a voltage sensor fast enough to keep up with neurons. After several trials, the group landed on one found in algae, and engineered a version that is both sensitive to voltage activity and responds to the activity very quickly.

The amount of light it puts out, however, wasn't bright enough to be useful in experiments. It needed an amplifier.

To meet this engineering challenge, Gong fused the newly engineered voltage sensor to the brightest fluorescing protein available at the time. He linked the two close enough to interact optically without slowing the system down.

"When the voltage sensing component we engineered detects a voltage potential, it absorbs more light," explained Gong. "And by absorbing more of the bright fluorescent protein's light, the overall fluorescence of the system dims in response to a neuron firing."

The new sensor was delivered to the brains of mice using a virus and incorporated into fruit flies through genetic modification. In both cases, the researchers were able to express the protein in selected neurons and observe voltage activity. They were also able to read voltage movements in different sub-compartments of individual neurons, which is very difficult to do with other techniques.

Read more at Science Daily

The LHC collides ions at new record energy

After the successful restart of the Large Hadron Collider and its first months of data taking with proton collisions at a new energy frontier, the LHC is moving to a new phase, with the first lead-ion collisions of season 2 at an energy about twice as high as that of any previous collider experiment. Following a period of intense activity to re-configure the LHC and its chain of accelerators for heavy ion beams, CERN1's accelerator specialists put the beams into collision for the first time in the early morning of 17 November 2015 and 'stable beams' were declared at 10.59am today, marking the start of a one-month run with positively charged lead ions: lead atoms stripped of electrons. The four large LHC experiments will all take data over this campaign, including LHCb, which will record this kind of collision for the first time. Colliding lead ions allows the LHC experiments to study a state of matter that existed shortly after the big bang, reaching a temperature of several trillion degrees.

"It is a tradition to collide ions over one month every year as part of our diverse research programme at the LHC," said CERN Director General Rolf Heuer. "This year however is special as we reach a new energy and will explore matter at an even earlier stage of our universe."

Early in the life of our universe, for a few millionths of a second, matter was a very hot and very dense medium -- a kind of primordial 'soup' of particles, mainly composed of fundamental particles known as quarks and gluons. In today's cold Universe, the gluons "glue" quarks together into the protons and neutrons that form bulk matter, including us, as well as other kinds of particles.

"There are many very dense and very hot questions to be addressed with the ion run for which our experiment was specifically designed and further improved during the shutdown," said ALICE collaboration spokesperson Paolo Giubellino. "For instance, we are eager to learn how the increase in energy will affect charmonium production, and to probe heavy flavour and jet quenching with higher statistics. The whole collaboration is enthusiastically preparing for a new journey of discovery."

Increasing the energy of collisions will increase the volume and the temperature of the quark and gluon plasma, allowing for significant advances in understanding the strongly-interacting medium formed in lead-ion collisions at the LHC. As an example, in season 1 the LHC experiments confirmed the perfect liquid nature of the quark-gluon plasma and the existence of "jet quenching" in ion collisions, a phenomenon in which generated particles lose energy through the quark-gluon plasma. The high abundance of such phenomena will provide the experiments with tools to characterize the behaviour of this quark-gluon plasma. Measurements to higher jet energies will thus allow new and more detailed characterization of this very interesting state of matter.

"The heavy-ion run will provide a great complement to the proton-proton data we've taken this year," said ATLAS collaboration spokesperson Dave Charlton. "We are looking forward to extending ATLAS' studies of how energetic objects such as jets and W and Z bosons behave in the quark gluon plasma."

The LHC detectors were substantially improved during the LHC's first long shutdown. With higher statistics expected, physicists will be able to look deeper at the tantalising signals observed in season 1.

"Heavy flavour particles will be produced at high rate in Season 2, opening up unprecedented opportunities to study hadronic matter in extreme conditions," said CMS collaboration spokesperson Tiziano Camporesi. " CMS is ideally suited to trigger on these rare probes and to measure them with high precision. "

Read more at Science Daily

Aging star's weight loss secret revealed

VY Canis Majoris is a stellar goliath, a red hypergiant, one of the largest known stars in the Milky Way. It is 30-40 times the mass of the Sun and 300,000 times more luminous. In its current state, the star would encompass the orbit of Jupiter, having expanded tremendously as it enters the final stages of its life.

The new observations of the star used the SPHERE instrument on the VLT. The adaptive optics system of this instrument corrects images to a higher degree than earlier adaptive optics systems. This allows features very close to bright sources of light to be seen in great detail. SPHERE clearly revealed how the brilliant light of VY Canis Majoris was lighting up clouds of material surrounding it.

And by using the ZIMPOL mode of SPHERE, the team could not only peer deeper into the heart of this cloud of gas and dust around the star, but they could also see how the starlight was scattered and polarised by the surrounding material. These measurements were key to discovering the elusive properties of the dust.

Careful analysis of the polarisation results revealed these grains of dust to be comparatively large particles, 0.5 micrometres across, which may seem small, but grains of this size are about 50 times larger than the dust normally found in interstellar space.

Throughout their expansion, massive stars shed large amounts of material -- every year, VY Canis Majoris sees 30 times the mass of Earth expelled from its surface in the form of dust and gas. This cloud of material is pushed outwards before the star explodes, at which point some of the dust is destroyed, and the rest cast out into interstellar space. This material is then used, along with the heavier elements created during the supernova explosion, by the next generation of stars, which may make use of the material for planets.

Until now, it had remained mysterious how the material in these giant stars' upper atmospheres is pushed away into space before the host explodes. The most likely driver has always seemed to be radiation pressure, the force that starlight exerts. As this pressure is very weak, the process relies on large grains of dust, to ensure a broad enough surface area to have an appreciable effect.

"Massive stars live short lives," says lead author of the paper, Peter Scicluna, of the Academia Sinica Institute for Astronomy and Astrophysics, Taiwan. "When they near their final days, they lose alot of mass. In the past, we could only theorise about how this happened. But now, with the new SPHERE data, we have found large grains of dust around this hypergiant. These are big enough to be pushed away by the star's intense radiation pressure, which explains the star's rapid mass loss."

Read more at Science Daily

Nov 25, 2015

Fossils Reveal How Giraffe Got Its Long Neck

Analysis of the neck bones of an extinct member of the giraffe family reveal how today's giraffe got its exceptionally long neck.

It has long been thought that the giraffe's neck was a result of evolution, but fossil evidence had been lacking.

In a paper published in Royal Society Open Science, scientists describe the neck of a "transitional" or "intermediate" species that existed about 7 million years ago.

The findings, by researchers at the New York Institute of Technology, are based on analysis of fossil vertebrae of Samotherium major, a giraffid that roamed parts of Eurasia, including Samos of Greece (where it was originally found and named), South Italy, Turkey, Moldavia, Iran, and China.

The vertebrae were compared with neck bones from the only two living members of the Giraffidae family - the giraffe (Giraffa camelopardalis) and okapi (Okapia johnstoni), a short-necked mammal that lives in central Africa.

Like all mammals, members of the giraffe family have seven bones in their neck.

While today's giraffe's neck is about two meters long, the neck of Samotherium major was about half that length, while the okapi neck is just 60 centimeters long.

Co-author Ms Melinda Danowitz revealed the ancient giraffid's neck was not only intermediate in length, but also in many morphological and proportional features.

"We can finally see the transitional stages in the elongation of the giraffe neck," she said.

Senior author Professor Nikos Solounais, also from the American Museum of Natural History, said the neck was reconstructed from no more than four individuals that were all excavated from Samos in Greece.

"The bones might not be one individual, but considering the rarity of well-preserved fossil necks, it is likely they came from very few individuals, and that several of the bones came from the same individual," he said.

Today's study builds on earlier published work by the team that showed Samotherium underwent the first stage of neck elongation, which involved elongation of the cranial, or front end, of each neck bone.

However the second stage involving elongation of the back end of each neck bone, or the caudal, was not evident.

Ms Danowitz said the Samotherium neck had other characteristics that were also intermediate between the giraffe and okapi.

She said in the okapi the sixth neck bone included a completed ridge on the bone surface known as the ventral ridge.

Read more at Discovery News

King Tut's Tomb: Secret Chamber Search Is On

The search for secret chambers in King Tutankhamun’s tomb will resume tomorrow and will last until Saturday, Egypt’s Minister of Antiquity announced.

The three-day investigation is expected to add new clues to help reveal what Minister of Antiquity Mamdouh al-Damaty called “the discovery of the century.”

“The search will involve the use of radar and infrared thermography,” Damaty told Egypt’s news site Ahram Online.

The new non-invasive probe follows a claim by Nicholas Reeves, a British Egyptologist at the University of Arizona, that high-resolution images of the tomb’s walls show “distinct linear traces” pointing to the presence of two still unexplored chambers behind the western and northern walls of the tomb.

According to Reeves, one chamber contains the remains, and possibly the intact grave goods, of queen Nefertiti, wife of the “heretic” monotheistic pharaoh Akhenaten, Tutankhamun’s father.

Reeves speculated that the tomb of King Tut was not ready when he died unexpectedly at 19 in 1323 B.C., after having ruled a short reign of nine to 10 years. Consequently, he was buried in a rush in what was originally the tomb of Nefertiti, who had died 10 years earlier.

Reeves and Damaty conducted a preliminary visual inspection of the tomb in September. The investigation was followed earlier this month by further tests, carried out by a team from Cairo University’s Faculty of Engineering and the Paris-based organization Heritage, Innovation and Preservation.

The researchers used infrared thermography to detect the temperature of the walls in the tomb.

According to Damaty, the analysis showed “differences in the temperatures registered on different parts of the northern wall” of the tomb.

Read more at Discovery News

How Terrorism Can Harm Your Brain

When ISIS terrorists attacked Paris on Nov. 13, they took 130 lives and wounded hundreds more. But their bloody acts may have injured far more people -- both survivors and the countless numbers who experienced the event vicariously through horrific media images -- in an insidious way, by causing potentially harmful changes in their brains.

Indeed, terrorism's effect on the brain is so powerful that those who survive attacks have significantly higher rates of post-traumatic stress disorder than those who make it through accidents or natural disasters. But terrorism also is linked to long-term problems such as anxiety and alcohol abuse in people who only have secondhand exposure to the event by watching it on television.

Recent research shows fear of future terrorist attacks can alter brain chemistry in a way that increases your risk of dying eventually from a heart attack or other ailments that might seem unrelated to the violence.

The latter study, published in 2014 in Proceedings of the National Academy of Sciences, looked at more than 17,000 Israelis, who live in a country where terrorist attacks are a frequent occurrence.

The subjects who had the most fear of terrorism tended to have resting heart rates that were 10 to 20 beats per minute faster than the norm, an indicator of increased risk for heart attacks and strokes. The elevated heart rate was linked to a change in brain chemistry. Blood tests revealed a decline in the function of acetylcholine, a neurotransmitter involved in responses to stress and which acts as a brake to the inflammatory response.

"Our brain reacts to acute stress situations by a rapid burst of acetylcholine release," explained study co-author Hermona Soreq, a professor of molecular neuroscience at the Edmond and Lily Safra Center for Brain Sciences at Hebrew University in Jersusalem.

"The brain sends the acetylcholine to body tissues through the vagus nerve; Since acetylcholine blocks inflammation responses, too much of it weakens the immune system. We found lower prospects to survive in patients after heart attack whose blood tests show weakened capacity to destroy acetylcholine."

Soreq said that terrorism-induced anxiety also causes the production of small molecules called microRNAs, which block the function of numerous other genes, and can alter regulation of the nervous system.

Terrorism triggers mechanisms hard-wired into the nervous system by evolution, which enabled our ancient ancestors to escape from animal predators and rival human clans. The human brain and vision system is fine-tuned to spot things that we should be afraid of, and then react to them in a flash -- even without consciously realizing it.

In a 2012 study, for example, researchers from the University of Edinburgh and New York University trained subjects to fear certain pictures by giving them mild shocks. Some subjects were allowed to look directly at the images, while others only got to glimpse them in one eye while researchers flashed a colorful image in the other eye to interfere with conscious perception.

Even with that hindrance, the subjects who got the one-eyed glimpse actually developed a fear response more quickly.

When a person spots danger -- say, a gunman who bursts into a theater -- the alarm is sounded in the amygdala, a sort of biological alarm system that triggers the body's response. It directs glands to release an array of chemicals such as adrenalin and cortisol, which shift the heart, lungs and muscles into high gear. The senses shift into narrowly focused hyper-awareness of information that might aid in survival.

A study published in Psychological Science in 2009, for example, found that fear made subjects see coarser lines, which help the brain to evaluate movement and distance, more clearly, while they couldn't make out fine lines as well as usual.

After a threat is over, in many cases, a survivor's brain gradually can shift back into normal operating mode. But not always. Studies have shown that between 28 and 33 percent of survivors of mass shootings and 34 percent of bombing survivors develop post-traumatic stress disorder -- far higher rates than people involved in terrifying accidents or natural disasters.

Survivors continue to relive the trauma and often suffer from symptoms such as irritability, difficulty concentrating, hypervigilant watchfulness, and an exaggerated startle response, and sometimes feelings of numbness.

Recent research by German scientists suggests that cortisol, one of the chemicals that the body releases in an effort to survive a terror attack, not only helps burn the event more vividly into a person's memory, but also helps to keep it vivid even after it is retrieved repeatedly.

But it's not only immediate survivors whose brains may be affected by terrorism. A study published in the New England Journal of Medicine in 2001 found that after the 9-11 attacks, 44 percent of U.S. adults and 35 percent experienced one or more substantial symptoms of stress, such as difficulty concentrating, repeated memories or dreams of the event, irritation and angry outbursts. The level of stress that people experienced was linked to the extent that they had watched TV coverage of the attacks.

Those effects sometimes last for years. Another study, published in 2008 in Journal of the American Public Health Association, looked at the effect of 9-11 on the mental health of office workers in Chicago, far away from the actual site of the attacks in New York and Washington.

Read more at Discovery News

Einstein's General Relativity Still Put to Test

A century after Albert Einstein unveiled a new concept to explain gravity, his so-called general relativity theory remains fertile ground for scientific observations and experiments.

Einstein’s revolutionary idea stemmed from his special theory of relativity, published a decade earlier, which wed space and time into a single continuum known as spacetime. Observers at different locations, for example, would see the same star exploding at different times, depending on how far away they were from the event. What is constant is the speed of light.

Special relativity did not take into account gravitational effects. Einstein toiled another 10 years to understand the physics and work through the math before unveiling his radically new idea in a four-part lecture at the Prussian Academy of Sciences that culminated on Nov. 25, 1915. Einstein published “The Field Equations of Gravitation” paper a week later.

“Before Albert Einstein came up with his general theory of relativity, we sort of pictured gravity as this magical force that connected different masses with one another,” said NASA astrophysicist Ira Thorpe, with the Goddard Space Flight Center in Greenbelt, Md.

Under Issac Newton’s theory of gravity, which had dominated physics for more than 200 years, if a mass in one part of the universe moved, all the other masses in the rest of the universe would instantly know and be affected by the motion.

That concept, however, ran counter to an implication of Einstein’s special relativity theory, which established a universal speed limit -- the idea that nothing can move faster than the speed of light.

Say one day the sun disappeared. Under Newtonian physics, the effect would be felt immediately on Earth. Under Einstein’s theory, it would take roughly eight minutes – the time it takes both light waves and gravitational waves, which also travel at the speed of light -- to cover the 93 million miles between Earth and the now-vanished sun.

Rather than masses exerting gravitational forces on one another, Einstein realized that it was spacetime itself that was bending, similar to what happens when a bowling ball rolls across a trampoline.

One of the newest frontiers opened by general relativity is the search for gravitational waves, a rippling of spacetime caused by massive objects in motion.

“They’re waves, much like water waves or light or any other kind of electromagnetic radiation, except here what’s ‘waving’ is space and time itself,” Thorpe said during a webcast panel discussion hosted by

Just like a bowling ball warps a trampoline more than a baseball, massive objects, such as black holes, bend spacetime more than relatively puny objects, like the sun.

“There’s a whole spectrum of gravitational waves, just like there’s a whole spectrum of electromagnetic waves. So, just like you have radio and infrared and visible and ultraviolet and X-ray and all the way up through gamma ray, you have the same type of thing with gravitational waves,” Thorpe said.

Though astronomers have not detected any gravitational waves yet, they know what frequencies and wavelengths different sources generate, thanks to computer modeling.

The longest gravitational waves were produced in the Big Bang explosion 13.8 billion years. “They get stretched out to the size of the universe as the universe expands. They kind of expand along with the universe,” Thorpe said.

Some scientists are studying the remnant cosmic microwave background radiation for telltale fingerprints of gravitational waves. Others have been hunting for gravitation waves set off by massive, fast-moving objects, such as binary black holes.

Unlike most electromagnetic telescopes, which have to be pointed, gravitational wave detectors are more like microphones that you just stick out and see what’s there, Thorpe said.

“You get sources from all directions and then you do data analysis to disentangle them,” he said.

Read more at Discovery News

Nov 23, 2015

Animal That Survives in Space Has Weird DNA

The only animal known to survive the extreme environment of outer space without the help of special equipment turns out to have the most foreign DNA of any species.

Water bears, also known as tardigrades, have genomes that are nearly one-sixth foreign, meaning that the DNA comes from creatures other than the animal itself, new research finds.

The discovery, published in the Proceeding of the National Academy of Sciences, adds to the evidence that tiny water bears are incredibly unique and seemingly indestructible animals. In 2007, some were even rocketed into space on the outside of a satellite.

When the satellite returned, many of the water bears were still alive. What’s more, some of the females had laid eggs in space, with the young hatching healthily, as though nothing had happened.

“We had no idea that an animal genome could be composed of so much foreign DNA,” co-author Bob Goldstein of the University of North Carolina at Chapel Hill said in a press release. “We knew many animals acquire foreign genes, but we had no idea that it happens to this degree.”

Water bears are segmented, eight-legged micro-animals that measure just a miniscule fraction of an inch long. Goldstein, lead author Thomas Boothby and their team determined that water bears acquire 6,000 foreign genes primarily from bacteria, but also from plants, fungi and various single-celled microorganisms.

This means that 17.5 percent of the water bear’s genome comes from these other sources.

The DNA is acquired via a process called horizontal gene transfer. Instead of just inheriting DNA, it is swapped between species.

Boothby said, “Animals that can survive extreme stresses may be particularly prone to acquiring foreign genes — and bacterial genes might be better able to withstand stresses than animal ones.”

Water bears have astounded scientists for years with their heartiness. For example, you can stick them in a freezer for a year. Within 20 minutes, the animal thaws out and starts to scurry around as normal.

The researchers suspect that when water bears are under conditions of extreme stress, such as desiccation, their DNA will break into small pieces. When the cell rehydrates, the cell’s membrane and nucleus (where the DNA resides) become temporarily “leaky,” such that DNA and other large molecules can pass through easily.

During this process, the water bears not only repair their own damaged DNA, but also stitch in the foreign DNA, creating a mosaic of genes that come from different species.

The prior record holder for most foreign DNA was another microscopic animal called the rotifer. It is now known that rotifers just have about half as much foreign DNA as water bears, though.

Read more at Discovery News

Captivating Blue Dragon Sea Slug Washes Up in Australia

It takes a lot of courage to go up against the venomous Portuguese man o' war -- a creature that sends even humans bolting out the water -- but the blue dragon is up for the challenge.

As it munches on the highly venomous siphonophore, the blue dragon intentionally eats the man o' war's toxic stingers, storing them within its own body. Now armed and dangerous with its victim's weapon, the blue dragon can impart a nasty sting on any would-be predators.

Also known as Glaucus atlanticus, the small sea slug is found floating along the surface many of the world's oceans, yet rarely seen by humans -- unless it washes ashore, as one did on Australia's Gold Coast earlier this week:

Griffith University marine invertebrates expert Kylie Pitt told the Gold Coast Bulletin that the "really weird" creatures "float upside down and move around using the water's surface tension."

"I have handled them before and wasn't stung, but I would not recommend anyone pick them up because they can have a painful sting," he added.

From Discovery News