Ground breaking hip and stem cell surgery completed using 3D-printed implant

Doctors and scientists in Southampton have completed their first hip surgery with a 3D printed implant and bone stem cell graft.

The 3D printed hip, made from titanium, was designed using the patient's CT scan and CAD CAM (computer aided design and computer aided manufacturing) technology, meaning it was designed to the patient's exact specifications and measurements.

The implant will provide a new socket for the ball of the femur bone to enter. Behind the implant and between the pelvis, doctors have inserted a graft containing bone stem cells.

The graft acts as a filler for the loss of bone. The patient's own bone marrow cells have been added to the graft to provide a source of bone stem cells to encourage bone regeneration behind and around the implant.

Southampton doctors believe this is a game changer. Douglas Dunlop, Consultant Orthopaedic Surgeon, conducted the operation at Southampton General Hospital. He says: "The benefits to the patient through this pioneering procedure are numerous. The titanium used to make the hip is more durable and has been printed to match the patient's exact measurements -- this should improve fit and could recue the risk of having to have another surgery.

"The bone graft material that has been used has excellent biocompatibility and strength and will fill the defect behind the bone well, fusing it all together."

Over the past decade Mr Dunlop and Professor Richard Oreffo, at the University of Southampton, have developed a translational research programme to drive bone formation using patient skeletal stem cells in orthopaedics.

The graft used in this operation is made up of a bone scaffold that allows blood to flow through it. Stem cells from the bone marrow will attach to the material and grow new bone. This will support the 3D printed hip implant.

Professor Oreffo comments: "The 3D printing of the implant in titanium, from CT scans of the patient and stem cell graft is cutting edge and offers the possibility of improved outcomes for patients.

"Fractures and bone loss due to trauma or disease are a significant clinical and socioeconomic problem. Growing bone at the point of injury alongside a hip implant that has been designed to the exact fit of the patient is exciting and offers real opportunities for improved recovery and quality of life."

Read more at Science Daily

Fast and curious: Electrons hurtle into the interior of a new class of quantum materials

As smartphones get smarter and computers compute faster, researchers actively search for ways to speed up the processing of information. Now, scientists at Princeton University have made a step forward in developing a new class of materials that could be used in future technologies.

They have discovered a new quantum effect that enables electrons -- the negative-charge-carrying particles that make today's electronic devices possible -- to dash through the interior of these materials with very little resistance.

The discovery is the latest chapter in the story of a curious material known as a "topological insulator," in which electrons whiz along the surface without penetrating the interior. The newest research indicates that these electrons also can flow through the interior of some of these materials.

"With this discovery, instead of facing the challenge of how to use only the electrons on the surface of a material, now you can just cut the material open and you have light-like electrons flowing in three dimensions inside the materials," said M. Zahid Hasan, a professor of physics at Princeton, who led the discovery.

The finding was conducted by a team of scientists from the United States, Taiwan, Singapore, Germany and Sweden and published in two papers in the journal Nature Communications. The first paper, published May 7, demonstrates that fast electrons can flow in the interior of crystals made from cadmium and arsenic, or cadmium arsenide. The second paper, published May 12, explores fast electrons in a material made from the elements bismuth and selenium.

In most materials, including copper and other metals that conduct electricity, electrons navigate an obstacle course of microscopic outcroppings, ledges and other imperfections that obstruct the tiny particles and send them scattering in the wrong directions. This causes resistance and the conversion of electrical current into heat, which is why electronic appliances become warm during use.

In topological insulators and the new class of materials the Princeton researchers studied, the unique properties of the atoms combine to create quantum effects that coax electrons into acting similar to a light wave instead of like individual particles. These waves can weave around and dodge -- and even move through -- barriers that would typically stop most electrons. These properties were theoretically proposed by Charles Kane and a team at the University of Pennsylvania from 2005 to 2007 and first observed experimentally in solid materials by the Hasan group in 2007 and 2008.

In 2011, the Hasan group detected this fast electron-flow in the interior of a material made from combining several elements -- bismuth, thallium, sulfur and selenium. The results were published in the journal Science.

In the new study in cadmium arsenide, the electrons have an average velocity that is 10,000 times more than that of the previous bismuth-based materials identified by the group. "This is a big deal," Hasan said. "It means the electrons can flow quite easily in the material and many more exotic quantum effects can now be studied. That just wasn't possible in the past."

The most promising application for these materials may be for a proposed "topological quantum computer" based on novel electronics that would use a property of electrons known as "spin" to do calculations and transmit information.

The quantum behavior in this new class of materials has led them to be called "topological Dirac semi-metals" in reference to English quantum physicist and 1933 Nobel Prize winner Paul Dirac, who noted that electrons could behave like light. Semi-metals that are "topological" are ones that retain their spatial electronic properties -- and their speedy electrons -- even when deformed by certain types of stretching and twisting.

The speeds achieved by these electrons have led to comparisons to another novel electronic material, graphene. The new class of materials has the potential to be superior to graphene in some aspects, Hasan said, because graphene is a single layer of atoms in which electrons can flow only in two dimensions. Cadmium arsenide permits electrons to flow in three dimensions. The new study redefines what it means to be a topological material, according to Su-Yang Xu, a graduate student in Hasan's lab and co-first author of the May 7 paper with postdoctoral research associate Madhab Neupane at Princeton and Raman Sankar of National Taiwan University.

"The term topological insulator is now quite famous, and the yet term 'insulator' means that there are no electrons flowing in the bulk of the material," Xu said. "Our study shows that electrons are flowing in the bulk of the material, so clearly cadmium arsenide is not an insulator, but it is still topological in nature, so this is a totally new type of quantum matter," he said.

Read more at Science Daily

Giant telescope tackles orbit and size of exoplanet

Using one of the world's largest telescopes, a Lawrence Livermore team and international collaborators have tracked the orbit of a planet at least four times the size of Jupiter.

The scientists were able to identify the orbit of the exoplanet, Beta Pictoris b, which sits 63 light years from our solar system, by using the Gemini Planet Imager's (GPI) next-generation, high-contrast adaptive optics (AO) system. This approach is sometimes referred to as extreme AO.

The Gemini Planet Imager snapped an amazingly clear and bright image of the gas giant Beta Pictoris b after an exposure of just one minute.

By using a series of these images and calibrating the AO system and camera, researchers were able to refine the estimate of the planet's orbit by looking at the two disks around its parent star. Disks, which are made up of dense gas and debris, surround young newly formed stars. The team observed that the planet is not aligned with Beta Pictoris' (its star's) main debris disk but is aligned to and potentially interacting with an inner warped component disk.

"Our goal is to understand how these planetary systems have developed," said Lisa Poyneer, one of the lead Lawrence Livermore authors of a paper appearing in a recent edition of the journal, Proceedings of the National Academy of Sciences. "If Beta Pictoris b is warping the disk, that helps us see how the planet-forming disk in our own solar system might have evolved long ago."

Furthermore, the team predicts that there is a small chance that the planet will "transit," that is, partially block its star, as seen from Earth in late 2017. This would allow a very precise measurement of the planet's size. Poyneer concludes: "GPI also measures the planet's spectrum, and hence chemical composition. Knowing what it is made of and how big it is will help us figure out how it formed."

For the past decade, Lawrence Livermore has been leading a multi-institutional team in the design, engineering, building and optimization of GPI, which is used for high-contrast imaging to better study faint planets or dusty disks next to bright stars. Astronomers -- including a team at LLNL-- have made direct images of a handful of extrasolar planets by adapting astronomical cameras built for other purposes. GPI is the first fully optimized planet imager, designed from the ground up for exoplanet imaging and deployed on one of the world's biggest telescopes, the 8-meter Gemini South telescope in Chile.

Read more at Discovery News

Caught in the act: Study probes evolution of California insect

A first-of-its-kind study this week suggests that the genomes of new species may evolve in a similar, repeatable fashion -- even in cases where populations are evolving in parallel at separate locations. The research is featured on the cover of the May 16 issue of Science.

A team of evolutionary biologists at Rice University, the University of Sheffield and eight other universities used a combination of ecological fieldwork and genomic assays to see how natural selection is playing out across the genome of a Southern California stick insect that is in the process of evolving into two unique species.

"Speciation is the evolutionary process that gives rise to new species, and it occurs when barriers prevent two groups of populations from exchanging genes," said Rice co-author Scott Egan. "One way to study how speciation occurs is to look for examples where partial reproductive barriers exist but where genes are still exchanged."

The stick insect Timema cristinae is one such example. Timema are closely related to "walking sticks," plant-eating insects that look like twigs. Timema's shape and color act as natural camouflage and help themavoid being eaten by predators, such as birds. More than a dozen unique species of Timema have evolved to feed on specific plants in California and northern Mexico.

One of these, T. cristinae, is found in two distinct varieties. One variety, or ecotype, feeds on the thin, needle-like leaves of a shrub called Adenastoma and features a distinct white stripe on its back that serves as camouflage. The other ecotype has no stripe and feeds on Ceanothus, a plant with wide green leaves where the stripe would stand out.

"Populations of T. cristinae on the two host plants have evolved many differences in their physical form while still exchanging genes," said Egan, a Huxley Faculty Fellow in Ecology and Evolutionary Biology at Rice. "These same populations have also evolved barriers to gene flow. We call this process 'speciation with gene flow,' and evolutionary biologists have long wondered if the genetic basis for this process is highly repeatable and if the genes involved are spread out across the whole genome or in a few discrete regions."

To find out whether this was the case, Egan and a dozen co-authors led by University of Sheffield biologist Patrik Nosil conducted four years of detailed genomic and ecological tests. They first had to sequence the genome for T. cristinae and identify which portions of the genome corresponded to particular biological functions. They then collected about 160 T. cristinae from the wild. Samples were collected at several geographic locations and were equally split between the ecotypes on the two host plants.

"We resequenced the genome of each individual that we collected and looked at which genes were differentiated between populations adapted to different host plants," Nosil said. "Because we also conducted an experiment in the field measuring evolution in real time, we gained information on how natural selection is pulling these populations apart."

For example, the team found that many of the genetic differences were related to the biochemical function of metal ion binding, and metals are known to influence differences in pigmentation and mandible shape between the two T. cristinae ecotypes.

Previous ecological studies have shown that Timema do not migrate long distances. Because of this, the team expected to find evidence of localized gene flow among individuals collected at specific geographic locations. The genomic tests confirmed this, but they also revealed a pattern in the way that natural selection was playing out at each of the localities.

"In particular, we found that there were regions of the genome that exhibited significant differences between populations from host plant 1 and host plant 2, regardless of where the individuals were collected," Nosil said.

That suggested that evolution might be occurring in the same repeatable fashion at each location. To further test this, the team devised an experiment to gather genomic data from individuals that were actively under selection.

"We took individuals from a mixed population of the striped versus the no-striped ecotype, and we transplanted them back into nature onto the two host plants in five different sets," Egan said. "We allowed them to go an entire generation, and then we resampled those populations, resequenced the genome of the survivors and compared those to the ancestors that we started with a year before. We tried to match up the allele frequency shifts in this experiment with the genome-level differentiation that we observed in our genome-resequencing populations. And what we found was that many of the regions that were highly differentiated in nature were the exact same regions that were responding to our selection experiment."

Egan said it was previously impossible to conduct this kind of study because of the expense of genomic tests. Though the genomes of many plant, animal and microbial species have been sequenced over the past decade, most of those are model organisms. Scientists use model organisms to study critical biological processes, but Egan said the study of nonmodel organisms is often the key to ecological questions, including those related to how the environment influences natural selection and speciation.

Read more at Science Daily

New Bone Grown from Monkey's Own Skin Cells

Researchers have been able to grow new bone using a monkey's own skin cells.

The US study is the first time such a development has been shown in an animal that is similar to humans.

Professor Martin Pera, program leader of the ARC Stem Cells Australia, says the work, published today in Cell Reports, is "another step towards the development of safe stem cell therapies for human disease".

The study uses induced pluripotent stem cells (iPSC), which are derived from adult skin cells and can be reprogrammed to work as other cells.

Pera says pluripotent stem cells can be used to make any type of healthy human tissue and therefore have great potential for treatment of disease.

However, he adds, knowledge of whether stem cell therapies will be safe and effective in a clinical setting is limited.

Senior author of the new study, Dr Cynthia Dunbar, at the National Heart, Lung, and Blood Institute in the US, says their findings go some way in addressing these concerns and sidesteps ethical issues surrounding the use of embryonic stem cells.

Previous work in this field has relied on scientists giving human iPSC products to immunodeficient mice, she says.

"But because of the species differences, the cells do not behave normally in mice, and the lack of the immune system means that issues of immune rejection or inflammation cannot be studied," says Dunbar.

Because monkeys are the closest model species to humans, with similar organ and tissue structure and immunity, testing monkey iPSCs in monkeys should be indicative of the safety and efficacy of the process in humans, Dunbar says.

For the study, skin cells were taken from rhesus macaques to form stem cells (iPSCs), which were then turned into bone-forming cells.

Dunbar says those "bone" cells were then implanted into the monkeys on ceramic particles that were already in use by reconstructive surgeons attempting to fill in or rebuild bone.

The implants were retrieved at eight, 12 and 16 weeks with bone shown to be forming as early as eight weeks, the authors report.

Dunbar says unlike in studies involving mice injected with iPSCs the risk of tumours developing in the rhesus monkeys appeared to be low.

"The teratomas (tumours) only formed following injection of very high doses of undifferentiated iPSCs into animals, and even then the teratomas grew very slowly," she says.

Pera says because the approach uses a technique to produce stem cells that can be customised to individual patients, it avoids the potential for immune rejection of the graft.

He describes the results from the US study as "encouraging in terms of the safety of pluripotent stem cell therapy".

"However, the study is small, it relates to the safety of only one type of specialised cell, and does not show directly that the bone grafts would heal or repair fractures," he adds.

Read more at Discovery News

This Beetle Fires Boiling Chemicals Out of Its Bum

A bombardier firing its boiling chemicals from two views: side and temporary blindness.

In his epic encyclopedia Natural History, the great Roman naturalist Pliny the Elder wrote of the bonnacon, a sort of bull whose defensive strategy was to hit its foes with blasts of dung “so strong and hot, that it burneth them that follow after him in chase, like fire, if haply they touch it.” Natural history in Pliny’s time, you see, consisted of a good amount of hearsay. From 12-year-old boys, apparently.

There is, though, a remarkable real-life version of the bonnacon: the bombardier beetle. While it doesn’t weaponize its dung per se, it has evolved a cannon in its caboose, where chemicals mixed in a special chamber violently burst out of the critter in a boiling, noxious, pungent spray that can repel even the most daring of predators.

There are hundreds of species of bombardier beetles all over the world, with various defensive mechanisms. Some have non-explosive, foamy excretions of chemicals, while others like the African bombardier beetle can actually aim their explosive spray in virtually any direction like an angry lawn sprinkler. We’ll be talking about the latter here. The spraying bombardier beetles, not lawn sprinklers.

Does This Cannon Make My Butt Look Big?

In the bombardier’s abdomen is a chamber that holds a mixture of hydrogen peroxide–the stuff you put on cuts and no, you shouldn’t try disinfecting your wounds with bombardier beetle explosions–and chemicals called hydroquinones. When the beetle feels threatened, this chamber empties into another reaction chamber that contains catalysts to kick off the explosion.

The bombardier’s crazy coloration scares away most predators, save for the vicious Australian wild blurry pushpin.

Here the hydrogen peroxide rapidly decomposes into oxygen and boiling water, while the hydroquinones oxidize into benzoquinones–highly irritating chemicals that have been known to stain the skin of human handlers a yellowish brown for up to three weeks. This mix explodes out of the beetle, not as a single stream, but as a volley of rapid-fire blasts, in what scientists have likened to the pulsing propulsion system of Germany’s V-1 “buzz bomb” in WWII. The consequent chemical burn (free idea for a metal band name: The Consequent Chemical Burn) incapacitates smaller attackers like ants, and spooks the hell out of much, much larger foes as well, such as unfortunate amphibians.

“You’ve got 100 degrees centigrade temperature, you’ve got a chemical burn, the steam comes off like a smoke, and then also the reaction kind of hisses,” said entomologist Terry Erwin of the Smithsonian Institute. That adds up to a bad situation for any hungry frog that pokes its tongue in the wrong place. “There might be 200 of these beetles under one rock, and they all fire at the same time, and you’ve got a smokescreen, or vaporscreen, as it were,” Erwin said.

An incredible defense to have evolved, for sure, but the chemicals here are actually quite uncomplicated. Hydrogen peroxide is a natural byproduct of metabolism in almost all living creatures. And insects use quinones to harden their shells. The bombardiers have just figured out how to store these chemicals instead of breaking them down or using them up.

The bombardier can fire these compounds more than 20 consecutive times before running out of ammo. But how can the beetle flash-boil chemicals to over 200 degrees Fahrenheit inside itself without melting? I mean, I’ve been on this planet for 29 years and I can’t even boil water in a pot without somehow injuring myself.

“The insect cuticle is pretty tough stuff, and this reaction chamber where it all happens is very, very dense-walled,” said Erwin. “And when they open the turret, then all of this stuff goes directly out of the beetle.”

The ant nest beetle, a cousin of the bombardier beetle, aims its spray by bouncing it off its wing covers. This one looks a bit like Arthur from The Tick, though it probably isn’t also a former accountant. But who am I to judge.

“They can actually swing that turret around and shoot over their head, shoot to the right, shoot to the left, underneath them,” added Erwin. “The only place they can actually not shoot is where their mouthparts are.” You wouldn’t want to get a taste of your own medicine if you were one of these beetles, now would you?

According to a study by the legendary late ecological chemist Thomas Eisner, such an incredibly evolved trait was likely driven by one of the world’s feistiest selection pressures: ants. You see, to escape swarming ants, ground beetles like the bombardiers have to unfurl their wings from covers and are unable to take flight as rapidly as, say, a bee. Having such a dexterous turret allows the bombardier to hold its ground against the ants to buy time, deftly dispatching the attackers clambering over its body. Indeed, some bombardier species’ bum cannons are so effective that their wings have even become vestigial and useless.

Now, I’d be remiss in fully profiling the bombardier beetle without mentioning that it has historically been a favorite of creationists, who argue that such a complicated mechanism couldn’t have evolved on its own. While we don’t have good fossils charting its evolution, we don’t need no stinking fossils to demonstrate the gradual development of the bombardier beetle’s cannon.

Read more at Wired Science

Rare Undersea Boneyards Reveal Whale, Rays

In a chance discovery, scientists found the first images of a dead whale shark and three dead rays on the bottom of the Atlantic Ocean.

Marine creatures naturally fall to the seafloor when they die, and their bodies can provide an important source of nutrients for bottom-dwellers, such as crabs. However, the sunken carcasses of even large animals like whales are rarely observed. Only nine vertebrate carcasses (or carcasses from animals with a backbone) have been documented over the course of five decades of deep-sea photography.

The new footage of the whale shark and three individual rays was inadvertently captured off the coast of Angola in West Africa by a camera-equipped remotely operated vehicle (ROV) conducting underwater surveys for the oil industry between 2008 and 2010, a group of scientists said.

At nearly three-quarters of a mile (1,210 meters) below the surface, all that was left of the whale shark (Rhincodon typus) was its fleshy head, pectoral fins and part of its spine, the scientists reported online May 7 in the journal PLOS ONE. The three rays, which likely belonged to the genus Mobula, were similarly reduced to their skeletons and little flesh. Scavengers — mostly eel-like fish known as zoarcids — were spotted feeding and roosting on the carcasses.

Previous studies have shown that so-called "whale falls" host complex ecosystems and support a diverse array of life from sharks and eels to bone-eating zombie worms and bacteria. Rare footage of these boneyards has even led to the discovery of new species, such as sea snails, worms, sea anemones and tiny crustaceans.

But the four new "fish falls" off the coast of Angola were not teeming with as much life as is typically found around a whale fall, the scientists said. Compared with marine mammals, elasmobranchs (a family that includes sharks, rays and skates) decompose more quickly and aren't as nutrient-rich.

Read more at Discovery News

Why Octopuses Don't Tie Themselves in Knots

Octopuses look like a tangle of squishy arms, and yet they never tie their limbs in a knot, finds a new study that determined octopus skin repels itself.

The discovery, published in the latest issue of Current Biology, is helping researchers to design soft robots, such as for surgical use, that can reshape their bodies without becoming a jumbled mess.

It also solves a mystery about octopuses, whose brains appear to be are unaware of what their two legs and six arms are doing. Instead, a chemical produced by octopus skin temporarily prevents octopus suckers from sucking.

"We were surprised that nobody before us had noticed this very robust and easy-to-detect phenomena," co-author Guy Levy of the Hebrew University of Jerusalem, said in a press release. "We were entirely surprised by the brilliant and simple solution of the octopus to this potentially very complicated problem."

We humans don't have such problems because our rigid skeletons limit the number of possibilities as to where our arms and legs could be.

"Our motor control system is based on a rather fixed representation of the motor and sensory systems in the brain in a formant of maps that have body part coordinates," explained co-author Binyamin Hochner.

He continued, "It is hard to envisage similar mechanisms to function in the octopus brain because its very long and flexible arms have an infinite number of degrees of freedom. Therefore, using such maps would have been tremendously difficult for the octopus, and maybe even impossible."

As a demonstration of that freedom, check out this video that shows just how amazingly flexible these marine animals can be:

For the study, Hochner and his colleagues observed the behavior of amputated octopus arms, which remain very active for an hour after separation. (Octopuses can grow their arms back, but doing so is energetically costly.)

Those observations showed that the arms never grabbed octopus skin, though they would grab a skinned octopus arm. The octopus arms didn’t grab Petri dishes covered with octopus skin either, and they attached to dishes covered with octopus skin extract with much less force than they otherwise would.

"The results so far show, and for the first time, that the skin of the octopus prevents octopus arms from attaching to each other or to themselves in a reflexive manner," the researchers wrote. "The drastic reduction in the response to the skin crude extract suggests that a specific chemical signal in the skin mediates the inhibition of sucker grabbing."

Read more at Discovery News

Bones in Submerged Cave May Be Earliest Native American

Divers mapping the underwater caves within Mexico's Eastern Yucatan Peninsula came upon a surprising find -- a superbly preserved skeleton dating close to the time when people first entered the New World.

"It was like a magnet and I remember swimming over to her remains and hovering in place about 12 inches from the skull, absolutely spellbound, for several moments," Susan Bird, a Bay Area Underwater Explorers diver, told Discovery News.

Subsequent underwater testing and analysis of this oldest, most complete skeleton found in the Americas has since provided evidence that modern Native Americans are directly related to the earliest inhabitants of the Americas, according to a study published today in the journal Science.

Dating close to the time when people first entered the New World, the early American, or Paleoamerican, skeleton features Native American DNA while showing a distinctly different skull shape. The research provides new clues to how the Americas were first populated.

It suggests the morphological differences between Paleoamericans, the first people to inhabit the Americas after the most recent ice age, and modern Native Americans are not the result of separate migrations from southeast Asia or even Europe. Rather, they belong to the same population that "evolved in place" in the Americas and Beringia, a now partially submerged landmass including parts of Siberia, Alaska and the Yukon.

Belonging to an adolescent girl, the skeleton was found in 2007 in a submerged chamber named Hoyo Negro (Spanish for Black Hole), deep inside a cave system on Mexico's Eastern Yucatán Peninsula, about 12 miles north of the city of Tulum.

"The moment we entered the site, we knew it was an incredible place. The floor disappeared under us, and we could not see across to the other side. We pointed our lights down and to the sides. All we could see was darkness," Alberto Nava of Bay Area Underwater Explorers, one of the divers who found the skeleton, told Discovery News.

About two months later, armed with powerful underwater lights, the divers reached the floor of the pit at about 170 feet. They found themselves in a bell-shaped structure 200 feet in diameter, whose center was littered with large boulders stacked on top of each other.

"As our eyes got accustomed to the environment, we started to notice large animal bones resting at the bottom and on the walls of the pit," Nava said.

Then one of the divers spotted a human skull resting on the top of a small ledge. The small cranium lay upside down and rested on the left humerus (upper arm bone) with other remains nearby.

"It had a perfect set of teeth and dark eye sockets looking back at us. We could see the rest of the upper torso spread to the left and down on the ledge," Nava said

Using photography, videography, three dimensional modeling and minimal sampling, researchers studied the skeleton without removing it from its watery grave. Only recently, due to unauthorized dives risking to damage the remains, the skull and other four bones were recovered and placed in an artifact conservation lab in Campeche, Mexico.

The international team of anthropologists, archaeologists, geneticists, and geologists was led by anthropologist James Chatters, owner of Applied Paleoscience, a consulting service in Bothell, Wash. He was the first to study Kennewick Man, a 9,300-year-old skeleton found in Washington in 1996.

Also showing the distinctive Paleoamerican rather than modern Native American traits, the Kennewick skeleton triggered a nine-year legal battle between scientists, the U.S. government and Native American tribes who claimed him as one of their ancestors and sought permission for reburial.

In 2004, a U.S. court ruling established there was no evidence connecting Kennewick Man with any existing tribe because the remains date back before recorded history and no cultural or biological link could reasonably be made.

The Hoyo Negro skeleton, which might reopen the debate, turned out to be much older than Kennewick Man.

"The skeleton produced the earliest radiocarbon age, confirmed in two separate laboratories, of any on the Americas," Chatters told Discovery News.

Indeed the human remains were dated between 12,700 and 12,900 years old.

"However, because the material we had to use for the age is one that is not entirely safe from contamination by old carbon in the rocks, we are being more conservative and giving the age as between 13,000 and 12,000 years," Chatters added.

Confirmation came from uranium-thorium dating of calcite encrusted on the bones, which provided a minimum age of 12,000 years ago, making the skeleton one of the six oldest humans yet found in the Americas, certainly the oldest most complete.

Anthropological analysis revealed the small skeleton, named "Naia" by the dive team (meaning “water nymph” in Greek) belonged to a slight female measuring only 4'10" tall. She is estimated to have been between 15 and 16 years old at the time of her death.

Chatters and colleagues also identified the remains of more than 26 large mammals which met their death in the pit. They included a gomphothere, an extinct elephant-like creature, which was dated to around 40,000 years ago, saber-toothed cats and giant ground sloths, which were largely extinct in North America by 13,000 years ago.

Extant species included puma, bobcat, coyote, Baird's tapir, collared peccary and a bear.

"When Naia and the animals entered the cave, the near-surface tunnels were dry, so they walked in from a ground-level entrance, probably a sink hole. They walked a considerable distance, as much as 600 meters," Chatters said.

He speculates that Naia, and the larges animals in particular, were drawn by a large, ephemeral pool of water in the bottom of Hoyo Negro.

"Yucatan was a dry place back then. Walking in the dark, they fell into the deep pit, from which there was no exit," Chatters said.

Indeed, Naia’s remains show fractures of pubic bones, which are consistent with a fall into a shallow pool from one of the upper passages.

"I think she died almost instantly, if not instantly," Chatters said.

The water level was down in the bottom of the shaft when Naia fell. Then, between 9,700 and 10,200 years ago, global glacier melted enough that rising sea levels submerged everything.

Like Kennewick Man, Naia does not feature the broader and rounder skulls of today's Native Americans. She bore a long and high cranium, a pronounced forehead, a low and flat nose. Her teeth projected outward from her small face.

Such different faces, skulls and teeth have led speculations that prehistoric Americans might represent an earlier migration from Southeast Asia or even Europe via a now submerged land mass where the Bering Sea is now.

But mitochondrial DNA testings -- maternally inherited DNA -- carried out from Naia's upper right third molar suggest a different scenario: Paleoamericans and Native Americans descended from the same land in Beringia.

"We found that the Hoyo Negro girl belonged to a mitochondrial lineage known as haplogroup D1," Deborah Bolnick, assistant professor of anthropology at the University of Texas at Austin, said.

Derived from an Asian lineage, haplogroup D1 is common to modern Native Americans and is found only in the Americas. The presence of this genetic marker indicates that the girl was maternally related to living Native Americans.

Read more at Discovery News

Stellar Swapping Responsible for Mysterious Magnetars

Earth is more than just the beautiful blue marble we all know and love; it’s also a giant magnet, with a field extending far out into space generated by the movement of molten elements deep within its core. This magnetic field protects surface life from harmful cosmic radiation, creates the glowing auroras in high-latitude skies, and tells compasses in both survival kits and animal brains which way it is to the poles.

Our sun is an even bigger and more complex magnet, with a field that stretches throughout the solar system and tangles into twisting and snapping knots across its surface. But there are even more powerful magnets out there in the galaxy — unbelievably dense stellar corpses with magnetic fields thousands of millions of millions of times more powerful than Earth’s. Called magnetars, they are created by the collapse of very massive stars but why they don’t become black holes instead has been a question that has long puzzled astronomers… and now they think they have the answer.

Magnetars are actually a rare type of neutron star, the leftover core of a star more than 10 times the mass of our sun that’s gone supernova. Neutron stars are incredibly dense, as they’re nearly an entire star’s worth of stuff collapsed into a ball the size of a small city. A teaspoonful of neutron star would weigh over five billion tons.

Neutron stars spin rapidly, emit powerful radiation — even by stellar standards — have a crazy gravitational pull, and very strong magnetic fields. But magnetars are like neutron stars on steroids; they blast out powerful gamma rays, have quite literally lethal magnetic fields (deadly from even hundreds of miles away), and are even more massive than neutron stars. There have been very few of them found in the galaxy, and why those couple dozen didn’t turn into black holes (what with all that mass) may be due to a little help from their stellar friends. In at least one magnetar’s case, a former friend.

An international team of astronomers studying a young star system 16,000 light-years away (Westerlund 1) known to contain a magnetar have spotted the “smoking gun” of a proposed theory to their formation: a low-mass, carbon-rich star speeding away from the scene, a star that could have only formed as one of a pair but has since been sent packing at high velocity.

The runaway star was once the more massive in a close binary pair, the researchers suggest. As it began to run out of fuel, it shed its outer layers (as stars do), transferring some of that material to its companion. The sharing of matter gave the lower-mass star extra spin, and as it gained the hand-me-down mass it, too, began to kick off its outer layers, eventually exploding in a supernova and flinging its erstwhile partner out into space (with a little extra mass back as a parting re-gift).

The combination of a turbocharged rotation rate and crash diet help to create a 40-solar-mass magnetar out of the remaining collapsed star, rather than a black hole or garden-variety neutron star.

Read more at Discovery News