May 17, 2014

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

May 16, 2014

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

May 15, 2014

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

May 14, 2014

Hurricanes on the Move! Tropical Storms Shift Toward Poles

Hurricanes and typhoons are migrating from the tropics toward the North and South poles, a new study finds.

In the past 30 years, the total number of storms has remained about the same in the tropics, said lead study author Jim Kossin, a climate scientist with the National Oceanic and Atmospheric Administration's National Climatic Data Center.

What has changed, however, is the number of successful storm births.

The new study found that tropical storms don't peak in the tropics as often as they did 30 years ago. Instead, more and more storms are reaching their maximum strength at higher latitudes, according to the report, published today (May 14) in the journal Nature.

"The tropics are becoming less hospitable for tropical cyclones, and the higher latitudes are becoming less hostile," Kossin told Live Science's Our Amazing Planet.

Tropical cyclones (the broad name for hurricanes, typhoons and tropical storms) spin up over and over in the same regions — a group of storm nurseries ringing the tropics — because of favorable wind patterns and ocean temperatures.

Storm nurseries stir

Kossin and his co-authors think a simultaneous expansion in the planet's tropical belts underlies the overall change in storm intensity. The tropics have widened by about a degree in latitude each decade since 1979, according to separate studies by other research groups. The expansion also could have pushed the ideal storm-forming regions toward the North and South poles.

"There is certainly compelling evidence the two are linked, but we're not sure exactly how — that's what we want to find out," Kossin said. "This is a link that needs to be examined."

The expansion of the tropics has been linked to global warming and ozone loss. But scientists still hotly debate the impact of global warming on hurricanes. Storms could become more or less frequent, more intense or a combination of these changes, researchers say.

"This study establishes another link between global climate change and global tropical cyclone activity," said Hamish Ramsay, a climate scientist at Monash University in Australia who was not involved in the research. "It also raises a number of new questions, though."

The poleward trek doesn't necessarily mean that ferocious storms will be hitting the Atlantic coastline more often. As climate changes, fluctuating wind patterns could cause tropical storms to move toward or away from coastlines, for instance. And the study didn't examine landfall, where storms do the most damage.

Another confounding factor: The Atlantic Ocean storm nursery did not move north in the past 30 years, the researchers reported. Kossin said he suspects that regional effects in the Atlantic, such as aerosol pollution (tiny airborne particles), could be offsetting the overall tropical widening.

Heading north

By tracking where tropical cyclones hit at their strongest point, called peak intensity, the scientists discovered that storms are heading north and south. This method avoids problems with comparing storms between different oceans, Kossin said. Determining peak intensity is relatively consistent among different storm-tracking centers, he said. Other criteria, such as when a tropical storm tips into hurricane strength, can vary from center to center, making comparisons difficult.

Read more at Discovery News

Toothy, 'Alien'-Looking Catfish Baffles Zoologists

A small, toothy fish, which researchers say resembles the terrifying creature from the movie "Alien," is turning out to be a big mystery for the scientists who study it.

Kryptoglanis shajii is a tiny, subterranean catfish with a number of defining skeletal features, including a bulging lower jaw similar to a bulldog's. The fish's strange, bony face has baffled researchers, who have been unable to classify the odd species.

Humans rarely catch sight of the tiny catfish, and it inhabits only one area in the world: the Western Ghats mountain range in Kerala, India. Though the fish lives underground, it has been known to emerge occasionally in the springs, wells and flooded rice paddies of the region.

The subterranean dweller is so elusive that scientists didn't categorize it as a new species until 2011. At that time, John Lundberg, emeritus curator of ichthyology at the Academy of Natural Sciences of Drexel University in Philadelphia, also began taking a closer look at the new breed of fish.

"The more we looked at the skeleton, the stranger it got," Lundberg, Drexel's resident fish zoologist and a professor in the university's School of Arts and Sciences, said in a statement. "The characteristics of this animal are just so different that we have a hard time fitting it into the family tree of catfishes."

From the outside, Kryptoglanis shajii looks similar to other catfish, but a closer look inside the fish yields some surprising discoveries, Lundberg said. He and his colleagues used digital radiography and high-definition CAT scans to study Kryptoglanis' bone structure, finding that the fish is missing several bony elements.

That discovery alone was not enough to cause a stir among the experts, who explain that many subterranean fish lack some of the bones possessed by others of their species. What did surprise the researchers, however, was that the shapes of some of Kryptoglanis' bones were utterly unique among fishes of any species.

Numerous individual bones in the catfish's face are modified, giving it a compressed front end with a jutting lower jaw — similar to a bulldog's snout. The tiny fish also possesses four rows of conical, sharp-tipped teeth, the researchers said.

Lundberg speculates that these multiple, unique bone structures in one part of the fish's body could mean that there is a functional purpose behind all the strangeness.

"In dogs, that was the result of selective breeding," Lundberg said. "In Kryptoglanis, we don't know yet what in their natural evolution would have led to this modified shape."

The researchers seem to have ruled out the possibility that the catfish's unusual mug resulted from a highly specialized diet. That's because, based on the fish's teeth and subterranean habitat, it most likely eats a relatively typical diet of small invertebrates and insect larvae, Lundberg said. Video footage of live specimens at feeding time also suggests that this tiny fish — at 4 inches (10 centimeters), it's smaller than the average adult's pinky finger — is perfectly capable of eating such food.

The mystery of Kryptoglanis has received attention from other researchers, as well. Ralf Britz, a fish researcher at the Natural History Museum of London, led a separate study of the species' unique bone structure. The research was published in the March 2014 issue of the journal of Ichthyological Exploration of Freshwaters.

Read more at Discovery News

Weird Loner Exoplanet Orbits Far From its Star

An exoplanet that orbits its star at a whopping distance of 2,000 times the sun-Earth distance — taking 80,000 (Earth) years to complete one orbit — has been discovered. As far as exoplanets go, that’s the most extreme orbit found to date.

This exo-oddball was found during an observing campaign seeking out new worlds around a group of young stars. GU Psc, a star that is roughly a third of the size of our sun, was recently identified as a member of the AB Doradus group and became a ripe target for this exoplanetary search.

These young AB Doradus stars are around 100 million years old and make attractive targets for exoplanetary searches through direct means. As the stars are so young, any planets in tow will still be hot after recently forming from stellar material. Therefore, by their nature, these worlds are radiating energy into space, illuminated in infrared light.

The most common methods used to detect exoplanets include the “transit” method and the “radial velocity” method. The former has been made famous by NASA’s Kepler space telescope that stared at one patch of the sky to see exoplanets drift in front of their parent stars, slightly dimming the starlight. The radial velocity method is commonly used by ground-based observatories that watch for the slight frequency shift of starlight caused by the gravitational wobble of an orbiting exoplanet.

Direct imaging, however, can be a hard task and very few exoplanets have been discovered by this means. But in the case of GU Psc b, the young gas giant world was identified by an international team using several observatories. This research has been published in the Astrophysical Journal.

“Planets are much brighter when viewed in infrared rather than visible light, because their surface temperature is lower compared to other stars,” said team leader Marie-Ève Naud, PhD student at the Department of Physics at the Université de Montréal. “This allowed us to identify GU Psc b.”

But the exoplanetary search wasn’t easy. “We observed more than 90 stars and found only one planet, so this is truly an astronomical oddity!” added Naud.

Read more at Discovery News

Milky Way's Fattening Behind Revealed

Astronomers have long been in the dark about what is happening just beyond the center of the Milky Way. Stars in this region are mostly hidden by dust.

The only clue has come from measuring neutral hydrogen, an indirect technique that fed computer models showing the Milky Way’s outer disk is flared.

Now, a new study adds meat to the theory with the discovery of five relatively young, pulsating stars, known as Cepheid variables in the region of the suspected flare. Cepheids' regular pulsations and well-measured changes in brightness make them good yardsticks to measure astronomical distances.

The telltale stars were found between about 19 trillion and 38 trillion miles (3-7 light-years) above and below the galactic plane, and between about 250 trillion and 420 trillion miles (43-71 light-years) from the center of the Milky Way.

“The presence of these relatively young -- less than 130 million years old -- stars so far from the galactic plane is puzzling, unless they're in the flared outer disk,” astronomer Michael Feast, with the University of Cape Town wrote in a paper published in this week’s Nature.

“We found the Cepheids at exactly the distance predicted for this increase in disk thickness,” Feast wrote.

Scientists don’t know exactly why the galaxy’s outer disk is fattening.

The thickening may be because there is less mass there to gravitationally corral the gas and stars into a flatter shape, such as what exists near the sun, astronomer Patricia Whitelock, with the South African Astronomical Observatory, wrote in an email to Discovery News.

“It is complex because one needs to take into account both the mass we observe -- such as the stars and gas -- and the dark matter which we only detect via its influence on the stars. Much more theoretical and observational work would be required to confirm this, or look for alternatives,” Whitelock said.

Read more at Discovey News

May 13, 2014

Wreck May Be Columbus' Sunken Santa Maria

Quick, finish this phrase learned by every school child: "The Nina, Pinta, and the ..." The Santa Maria is one third of the most famous trio of ships in history -- the ship in which Christopher Columbus himself sailed -- and if a leading underwater archaeologist is correct, it's lying on the sea floor off the northern coast of Haiti.

The researcher, Barry Clifford, commanded a recent reconnaissance dive to the site, and he's certain they have found the ship's remains.

"All the geographical, underwater topography and archaeological evidence strongly suggests that this wreck is Columbus' famous flagship, the Santa Maria," Clifford told the The Independent.

Columbus set sail in the Santa Maria in 1492, alongside the Pinta and Nina, in an effort to stake out a trade route to Asia by heading west. But, instead of Asia, he found the future vacation spot of the Bahamas.

A couple of months later, the Santa Maria, with Columbus aboard, struck a reef and had to be abandoned. Its location has been a mystery for more than 500 years -- until perhaps now.

Columbus, after the wreck, built a fort nearby, and that fort -- whose probable location was determined by other archaeologists in 2003 -- figures in Clifford's assertion that he's found the Santa Maria.

Simply put, the shipwreck is in the right spot, relative to the fort, and other data points such as undersea topography, Columbus's own diary notes, and local currents seem to be a match as well.

The physical wreckage itself is not a new discovery. Clifford had already found and taken pictures of it in 2003, though at the time he did not know it was the Santa Maria. But the recent recon dives made by his team, along with a review of the 2003 dive photographs and fort location data, nudged the puzzle pieces into place.

Of particular interest in those 2003 photographs of the wreckage was what looked like the exact type of cannon documented to have been aboard the Santa Maria. The recent dives taken by the team had the goal of definitively identifying that cannon.

Read more at Discovery News

Mummified Fetus Found in Tiny Ancient Egyptian Sarcophagus

A suspected fake mummy currently on display at an Egypt center in Wales, in fact contains a fetus 12 to 16 weeks into development, CT scan has revealed.

Known as W1013, the 20-inch artifact is a case made of cartonnage — layers of linen stiffened with plaster or glue — and belongs to the Wellcome collection at Swansea University’s Egypt Center, which houses more than 5,000 objects. Most of them were collected by the Victorian pharmaceutical entrepreneur and archaeologist Sir Henry Wellcome on excavations in Egypt.

The tiny mummy came to Swansea in 1971, but nothing is known about where Wellcome obtained it.

The mummy has long puzzled experts. It is colorfully decorated in a style dating back to the 26th Dynasty, around 600 B.C. .

The inconclusive results of an X-ray carried out in 1998 combined with meaningless inscriptions painted on the cartonnage case, suggested the mummy could have been a 19th century forgery.

“But it’s not unusual for sham hieroglyphs to be placed on coffins. Undoubtedly this would indicate that the maker of the piece was not literate,” curator Carolyn Graves-Brown told Discovery News.

Further research solved the mystery.

Last month, Swansea University’s Paola Griffiths of the Clinical Imaging College of Medicine, CT scanned the artifact.

It was then revealed the majority of the interior of the case is taken up by what appears to be linen bandages.

Within those folded strips of material, the CT scan showed a darker area about 3 inches long which researchers identified as a fetus in fetal position and with a placental sac. What could be the fetus’s femur was also identified.

“The length of the femur together with the size of the dark patch is consistent with that of a 12 to 16-week-old fetus,” Graves-Brown said.

“Another dark patch suggests the presence of an amulet and there are several areas with dark circles resembling strings of beads or tassels,” she added.

Decorated with criss-cross pattern of rhombus shapes perhaps imitating the bead net placed over some other mummies, the cartonnage case might provide some clues on the unborn baby’s sex.

The face is painted in reddish-brown, a color usually associated with men. Moreover, the heavy, yellow and blue striped wig and wide collar are most common on male coffins.

But Graves-Brown cautions: “As the fetus is only 12-16 weeks and is not in a perfect state of preservation I would not guess the sex,” he said.

Read more at Discovery News

Fossils Reveal Post-Asteroid Cold Snap Doomed Dinos

The first-ever fossil proof of dramatic global cooling after the cosmic impact that ended the Age of Dinosaurs has been discovered.

The darkness and cold from the dust and ash thrown up by the giant collision was likely the main driver of the resulting mass die-off, known as the K-T extinction, scientists say. This extinction at the end of the Cretaceous period finished the reign of the dinosaurs. The only dinosaurian survivors were the birds; other reptiles such as turtles and crocodiles survived as well, although these are not descended from dinosaurs.

The prime suspect behind this disaster is a cosmic impact from an asteroid or comet. Scientists have found evidence of this collision near the town of Chicxulub (CHEEK-sheh-loob) in Mexico in the form of a giant crater more than 110 miles (180 kilometers) wide. The explosion that carved out this crater, likely caused by an object about 6 miles (10 km) across, would have released as much energy as 100 trillion tons of TNT, more than a billion times more than the atom bombs that destroyed Hiroshima and Nagasaki combined.

"When such an asteroid hits the Earth, the results are devastating," said lead study author Johan Vellekoop, a PhD candidate in paleoclimatology at Utrecht University in the Netherlands. "The impact itself releases an enormous amount of energy, so much that in the first hours after the impact, the air is heated up, igniting global wildfires."

Speculative cooling

In principle, such impacts also loft dust and soot into the atmosphere, "blocking incoming sunlight," Vellekoop said. "The sun is both our source of light as well as our main source of heat — hence, when sunlight can no longer reach the surface of the Earth, this surface rapidly cools down, creating a so-called 'impact winter,' a period of darkness and cold lasting for decades."

Prior studies hint that the impact winter reduced the amount of sunlight reaching Earth's surface by as much as 80 percent, cooling the land from tropical warmth to below freezing. This darkness and cold would have killed off plants and caused a global collapse of terrestrial and marine food webs.

"Ultimately, more than 50 percent of all plants and animals on Earth died out because of this," Vellekoop said.

However, until now, scientists had lacked fossil evidence of this impact winter, because this severe cold spell might have only lasted months to decades, too short a time period to be captured in a fossil record stretching across millions of years. In addition, many of the algae that produce the chalky fossils scientists use to estimate ancient ocean surface temperatures went extinct during the end-Cretaceous mass extinction.

"Our study is the first to show that this period of darkness and cold indeed took place," Vellekoop told Live Science.

Vellekoop and his colleagues focused their research on rocks exposed along the Brazos River between Waco and Hearne, Texas. These rocks originated from sediments deposited on the floor of a sea that existed in the area during and after the end of the Cretaceous.

Micro fossils

The scientists analyzed organic compounds from microbes known as Thaumarchaeota, which adjust the composition of fat molecules in their membranes as sea surface temperatures change.

The researchers investigated organic compounds from Thaumarchaeota in Bravos River sediments of the same age as the Chicxulub impact. These sediments held coarse layers of broken shells — possibly traces of a post-impact tsunami — and anomalously high concentrations of iridium, a metal rare on Earth's surface but more common in space rocks.The findings suggest ocean temperatures fell dramatically after the impact, cooling from about 86 degrees F (30 degrees C) to about 73 degrees F (23 degrees C).

"Working on an event 66 million years ago, it is incredible that we could resolve sea water temperature changes within decades," Vellekoop said.

Read more at Discovery News

After Neutron Star Death-Match, a Black Hole is Born

What happens when two neutron stars collide? Using a sophisticated computer simulation, NASA scientists have visualized this violent scenario in awesome degenerate-matter-crushing detail.

Neutron stars are the result of supernovae spawned by stars 8-30 times the mass of our sun. Occasionally, however, two neutron stars may meet, becoming entangled in a deep gravitational embrace. Should this scenario play out, one of the most powerful known explosions in the Universe may be sparked — a fast gamma-ray burst (GRB).

But before two neutron stars collide, what happens to their structures? What kind of insanely powerful tidal forces are at play?

In a simulation released today (May 13) by NASA Goddard Space Flight Center scientists, two neutron stars are placed a mere 11 miles apart. Keep in mind that although both neutron stars are 1.5 and 1.7 times the mass of our sun, all of that matter is packed into a tiny sphere only 12 miles wide. As a result, their densities and gravitational fields are immense — a teaspoonful of neutron star material would weigh as much as Mount Everest. The crushing gravitational forces ensure that atomic structures cannot be sustained, collapsing the material into a neutron degenerate state — only the structure of the neutrons themselves prevent the neutron star’s gravity from collapsing it into a point, forming a black hole.

Should more mass be added to the neutron star, a mass threshold may be reached when the gravitational forces overwhelm even the neutron degenerate pressure, causing it to collapse.

As the simulation unfolds, the neutron stars’ savage tidal forces rip each other to shreds, cracking open their thin crusts and shedding huge quantities of material into space. As they are so close to one another, the two neutron stars rapidly spin, merging in a fraction of a second. The progression of this simulated neutron star merger produces a ring doughnut-shaped material that forms about the genesis of the new-born black hole in its center.

Simulating these violent events are important for our understanding of not only how some black holes are created, but it can develop the science behind GRBs. As an extension, the mysterious source of the heaviest elements in the Universe may be found in these events where the rapid cohesion of neutron stars — and the resulting explosions — could forge rapid-neutron capture (or ‘r-process‘) elements.

Read more at Discovery News

Watch Saturn Snuggle Up With the Moon Tonight

On Tuesday evening (May 13), as the moon, just one night from full phase rises in the east-southeast sky it will be accompanied by a very bright yellowish-white "star" shining off to its lower left. That "star" will be the planet Saturn.

Saturn is currently shining bright in the night sky, just a few days after reaching opposition — its best display for stargazers — on Saturday (May 10). The planet shines at brilliant magnitude of zero on the brightness scale, making it virtually equal to the bright star Arcturus visible high above Saturn.

There is a distinct difference between Saturn and Arcturus though. While both are roughly of the same brightness (Saturn is just a trifle fainter) Arcturus twinkles and glimmers with an orange hue compared to Saturn which shines with a steady and sedate yellowish-white color.

So despite its relative close proximity to the moon, Saturn will still manage to stand-out quite well. And what will be especially interesting will be to watch how the moon seems to approach Saturn during the course of the overnight hours.

At dusk on Tuesday, Saturn will appear about 5.5 degrees to the lower left of the moon. (Your closed fist held out at arm's length covers about 10 degrees of the night sky). The moon will move toward Saturn at its own apparent width (one-half degree) per hour during the night.

So by dawn on Wednesday (May 14), the Saturn and the moon will be low in the west-southwest, the moon having moved to within 2.5 degrees to the lower right of the ringed planet. More interestingly, from the southern half of Australia, New Zealand and Victoria Land (Antarctica), the moon will occult (hide) Saturn on Wednesday evening.

Read more at Discovey News

May 12, 2014

HADES searches for dark matter: Astrophysicists cross 'Dark Photon' off the list in top position

Although Dark Energy and Dark Matter appear to constitute over 95 percent of the universe, nobody knows of which particles they are made up. Astrophysicists now crossed one potential Dark Matter candidate -- the Dark Photon or U boson -- off the list in top position. This is the result of recent HADES experiments, where researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and from 17 other European institutes try to pin down the nature of Dark Matter. These negative results -- recently published in Physics Letters B -- could even lead to challenges of the Standard Model of particle physics.

The interpretation of current astrophysical observations results in the striking mass-energy budget of matter in the universe: 75% Dark Energy and 20% Dark Matter. Only about 5% of the universe consists of "ordinary," baryonic matter.

Many attempts have been made to explain the nature of Dark Matter. Researchers believe that Dark Matter is comprised by hitherto unknown particles which do not fit into the Standard Model of particle physics. The Standard Model is a theoretically sound quantum field theory with fundamental matter particles, such as quarks (bound in hadrons, e.g., baryons) and leptons (e.g., electrons and neutrinos), which interact via exchange of force-carrier quanta, called gauge bosons (e.g., photons). Some of these species acquire their masses by the interaction with the Higgs boson. While evidences for the Higgs boson were found recently at CERN, the Standard Model looks now complete when supplemented by some neutrino masses, and nothing else seems to be needed to understand the wealth of atomic, sub-nuclear and particle physics phenomena. Nevertheless, Dark Matter appears not to be explained by any of the constituents of the Standard Model. This status of the affair has initiated worldwide efforts to search for Dark Matter candidates.

Beyond the Standard Model

Searching a needle in the haystack is simpler: one knows both the wanted object (the needle) and the place (the haystack). In the case of Dark Matter the object is unknown, and the localization, e.g. in galactic halos, is also not constraining the loci of interest. To specify the search goal one can envisage diverse hypothetical candidates, such as certain hypothetical particles beyond the Standard Model, which fulfill requirements qualifying them as constituents of Dark Matter.

Dark Energy drives the presently observed accelerated expansion of the universe. Dark Energy is homogeneously distributed and can be attributed to a cosmological constant or vacuum energy. In extreme cases it may cause, in the future, such a sudden expansion that anything in the universe is disrupted -- this would be the Big Rip. Dark Matter, in contrast, is bumpy and is needed to explain the formation of the observed density distribution of visible matter in the evolving universe, evidenced by the hierarchy of structures from (super)clusters of galaxies, galaxies, stars, planets and other compact objects such as meteorites, etc.

Among the lists of candidates of Dark Matter is a hypothetical particle, often dubbed U boson or Dark Photon. These nicknames refer to the underlying theory construction: a second unitary ("U") symmetry allows for quanta which are, in one respect, similar to photons -- namely gauge bosons -- but in another respect different from photons -- namely attributing to these quanta a mass, making them to Dark Photons because of a very weak interaction with normal matter. Very similar to photons the Dark Photons can decay into electron-positron pairs, if they have the proper virtuality. Combining the chain of hypotheses one arrives at a scenario, where an "ordinary" virtual photon converts into a Dark Photon which decays afterwards into an electron-positron pair.

Needle and Haystack

If a Dark Photon or U boson would exist with the assumed properties mentioned above and would have a mass, a certain width and a certain coupling strength to the photon, then the "needle" is specified: a resonance-type signal showing up at an invariant electron-positron mass equal to the U boson mass. The "haystack" is specified too: invariant mass spectra, i.e. electron-positron distributions. A prerequisite is an understanding of the overall shape of these distributions.

Up to now the search for such a signal of a U boson as a candidate for Dark Matter has remained unsuccessful. Together with many other searches for the other candidates of Dark Matter the situations becomes more and more intricate. Cosmology on precision level requires the existence of Dark Matter; however, the various experiments have not found any positive hint. The negative results on the U boson by HADES and other experiments make the hunt for new physics beyond the Standard Model more challenging. For instance, high-precision experiments on the magnetic moment of the muon delivered hints for a discrepancy with predictions by the Standard Model. The discrepancy has been proposed to be resolved by the U boson. But the recently achieved negative search results seem to exclude such an option. This gives the impression that the tension of the Standard Model and cosmological request of extensions as well as small deviations of the Standard Model predictions and data, such as the muon magnetic moment and other observables, is increasing, thus making this frontier of physics very fascinating with high discovery potential.

Read more at Science Daily

The Art and Science of NASA’s Best Exoplanet Illustrations

Except in a few rare cases, we can’t directly see planets outside of our own solar system. Just about every time a new exoplanet is discovered, the announcement is accompanied by an artist’s rendering of the world.

The drawings are often impressive feats, managing the tricky task of being both beautiful and scientifically accurate, while depicting something that no one has ever seen before. But each time you see one, you might wonder how closely they represent reality and what part of them is pure fantasy?

“We’re in the job of telling a story with these pictures,” said visualization scientist Robert Hurt of Caltech, who works with NASA to make exoplanet renderings. “The science visualization process is always starting with one or two data points and trying to make an engaging illustration.”

Many new exoplanet discoveries have come from NASA’s Kepler space telescope, a space-based observatory that carefully watched the light of more than 150,000 stars to try and detect a tiny dimming of brightness (though sadly, it suffered a malfunction last year that has rendered it inoperable). This dip represents a planet passing in front of that star and eclipsing its light. Kepler can’t give astronomers much more than a few pieces of information about each exoplanet; its approximate size, the distance from its star, the length of its year, and an estimate of its surface temperature.

The Kepler science team takes this data to Hurt and his collaborator, animator Tim Pyle, and works with them to produce illustrations. Together, they decide what aspects of the exoplanet they want to highlight. Kepler-186f, a recently discovered Earth-sized planet that might have liquid water on its surface, has been designated “Earth’s cousin.” So the image from NASA’s visualization team needed to suggest the idea that this place was a like home, just not exactly.

Hurt and Pyle used a few tricks to do this. The illustration of Kepler-186f (seen in the first slide above) looks at first glance like Earth, with landmasses, an atmosphere, and clouds, but upon closer inspection starts to seem more and more alien. The ice caps, for instance, are larger than ours, and light from the star has a different quality than the white sunlight we receive.

Though Kepler’s data couldn’t say for certain if there’s water on the planet’s surface, it’s a reasonable idea given the distance at which Kepler-186f orbits around its parent star. Therefore, the planet in the drawing has oceans. But to make things less-Earth like, the team went with a 50/50 ratio of water to land, rather than our planet’s 70/30 split. They also discussed the possibility of plant life, talking with astrobiology experts about what color this vegetation might be. Because the star produces more light in the red range of the electromagnetic spectrum, plant life would likely not be the familiar green of Earth, but rather a shade of orange. But because it leaps quite far into speculation, the artists didn’t want to come out and say for certain that there would be plants on Kepler-186f, settling instead on a coppery tint for the landmasses.

“We wanted to be consistent with the idea that there was life or plants, without saying there’s plants there,” said Pyle.

Hurt said color is a powerful part of the artists’ storytelling toolkit, and the closer the overall palette matches Earth’s, the more Earth-like the world is implied to be. Painting an exoplanet’s oceans the same cobalt blue of our own world will make a viewer naturally feel that it’s more like home, while lighter or darker blue shades could imply exoticness. The artists went through several iterations for the Kepler-186f drawing, giving it tweaks to “de-Earth” it, until it represented exactly what they wanted.

“We know we’re going to have people running by a newspaper stand, and seeing a headline that reads ‘NASA finds another Earth’ with this graphic next to it,” said NASA’s public affairs officer Michele Johnson, who coordinates Kepler’s press releases. “So we wanted to be very smart about the little we do know, saying this is our best interpretation, with a healthy amount of imagination as well.”

There are of course deviations from what’s physically possible. Most of these artistic shots are positioned behind a planet, with the star’s light on the opposite side. In real life, this would make the planet’s surface pitch black, with only a small sliver of daylight, but the picture needs to give a good view for the reader, instead showing a brightly lit surface. In the case of the Kepler-186f image, four other exoplanets can be seen shining up close to the star (with one even transiting in front of it to remind viewers of Kepler’s method of detection). These planets are far brighter and larger than they would be to an observer at the exoplanet, but serve as embellishments for the sake of a good story.

Read more at Wired Science

Origin of Mysterious Jellyfish Lightning 'Sprites' Revealed

Red electrical flashes that mysteriously hover above some thunderstorms have long puzzled scientists, but now, new research reveals how these alienlike atmospheric sprites form.

Sprites form at irregularities in the plasma, or charged particles of gas, in the ionosphere, the layer just above the dense lower atmosphere, about 37 to 56 miles (60 to 90 kilometers) above the Earth's surface, a study found. Since disturbances in the ionosphere can affect radio communication, sprites could be useful for sensing such disturbances remotely, researchers say.

"We would like to know how sprites are initiated and how they develop," Victor Pasko, an electrical engineer at Penn State and author of the study published May 7 in the journal Nature Communications, said in a statement.

Sprites are large electrical discharges that occur above thunderstorms. They resemble reddish-orange jellyfish with bluish tentacles streaming down.

But while sprites require thunderstorms, not all thunderstorms produce sprites. Recent studies suggested that ionosphere irregularities were required for these ghostly flashes to occur, but evidence for them was lacking.

In the study, Pasko and his colleagues studied high-speed video of sprites, and developed a model for how the strange lightning evolves and disappears. They used the model to try to recreate sprite-forming conditions.

Analysis of the videos showed that streamers snake downward from the sprites much more quickly than they spread horizontally, suggesting plasma irregularities were driving the streamer spread.

To study sprite dynamics, the team used a two-dimensional mathematical model of the movement of charged particles in the sprite. They used the model to recreate how sprites are formed, using it to see how the streamers originated and how large the plasma irregularities were.

Several sources could be causing these irregularities in the plasma. The existence of a previous sprite is the most obvious, but there were none that occurred in the region studied that occurred close enough in time — unless the irregularities last much longer than scientists suspect.

Read more at Discovery News

Star Birthing in Violent Galaxy Mergers

When two galaxies collide, astronomers witness a frenzy of star formation creating what are known as “starburst galaxies.” Although this is known, it’s a little counter-intuitive; during galactic mergers, the swirling interstellar gases are so turbulent that star formation should be switched off. So what’s going on?

Using two of Europe’s most powerful supercomputers, French astrophysicists simulated 300,000 light-years of interstellar gas inside a Milky Way-like galaxy (on the TGCC Curie supercomputer in France) and a volume of gas, 600,000 million light-years wide, inside two merging galaxies (on the SuperMUC supercomputer in Germany). Committing millions of hours of computational time, the simulation replicated the random motions of gas inside the galactic disks, resolving chaotic features fractions of a light-year across.

It is known that dense clouds of interstellar gas can collapse under mutual gravity, eventually sparking fusion and new stars. But in the turbulent wake of a galactic merger, star formation should be hindered, not accelerated. Turbulence should disrupt star forming regions, fragmenting the cloud. As these simulations prove, however, it is this turbulence that actually accelerates star birth, driving starburst galaxies.

The researchers were able to compare the two simulations, showing that in the collision model, violent turbulence makes interstellar gases ripe for compression (and not dispersion), accelerating star birth.

“This is a big step forward in our understanding of star formation, something only made possible by the similarly major and parallel advances in computing power,” said lead researcher Florent Renaud of the AIM institute near Paris. “These systems are helping us unlock the nature of galaxies and their contents in ever more detail, helping astronomers to slowly assemble their complete history.”

Read more at Discovery News

May 11, 2014

Paleontologists discover new fossil organism

Scientists at the University of California, Riverside have discovered a fossil of a newly discovered organism from the "Ediacara Biota" -- a group of organisms that occurred in the Ediacaran period of geologic time.

Named Plexus ricei and resembling a curving tube, the organism resided on the Ediacaran seafloor. Plexus ricei individuals ranged in size from 5 to 80 centimeters long and 5 to 20 millimeters wide. Along with the rest of the Ediacara Biota, it evolved around 575 million years ago and disappeared from the fossil record around 540 million years ago, just around the time the Cambrian Explosion of evolutionary history was getting under way.

"Plexus was unlike any other fossil that we know from the Precambrian," said Mary L. Droser, a professor of paleontology, whose lab led the research. "It was bilaterally symmetrical at a time when bilaterians -- all animals other than corals and sponges -- were just appearing on this planet. It appears to have been very long and flat, much like a tapeworm or modern flatworm."

Study results appeared online last month in the Journal of Paleontology.

"Ediacaran fossils are extremely perplexing: they don't look like any animal that is alive today, and their interrelationships are very poorly understood," said Lucas V. Joel, a former graduate student at UC Riverside and the first author of the research paper. Joel worked in Droser's lab until June 2013.

He explained that during the Ediacaran there was no life on land. All life that we know about for the period was still in the oceans.

"Further, there was a complete lack of any bioturbation in the oceans at that time, meaning there were few marine organisms churning up marine sediments while looking for food," he said. "Then, starting in the Cambrian period, organisms began churning up and mixing the sediment."

According to the researchers, the lack of bioturbators during the Ediacaran allowed thick films of (probably) photosynthetic algal mats to accumulate on ocean floors -- a very rare environment in the oceans today. Such an environment paved the way for many mat-related lifestyles to evolve, which become virtually absent in the post-Ediacaran world.

"The lack of bioturbation also created a very unique fossil preservational regime," Joel said. "When an organism died and was buried, it formed a mold of its body in the overlying sediment. As the organism decayed, sediment from beneath moved in to form a cast of the mold the organism had made in the sediment above. What this means is that the fossils we see in the field are not the exact fossils of the original organism, but instead molds and casts of its body."

Paleontologists have reported that much of the Ediacara Biota was composed of tubular organisms. The question that Droser and Joel addressed was: Is Plexus ricei a tubular organism or is it an organism that wormed its way through the sand, leaving a trail behind it?

"In the Ediacaran we really need to know the difference between the fossils of actual tubular organisms and trace fossils because if the fossil we are looking at is a trace fossil, then that has huge implications for the earliest origins of bilaterian animals -- organisms with bilateral symmetry up and down their midlines and that can move independently of environment forces," Joel said. "Being able to tell the difference between a tubular organism and a trace fossil has implications for the earliest origins of bilaterian organism, which are the only kinds of creatures that could have constructed a tubular trace fossil. Plexus is not a trace fossil. What our research shows is that the structure we see looks very much like a trace fossil, but is in fact a new Ediacaran tubular organism, Plexus ricei."

Read more at Science Daily

Newtown School Board Shuts Down Conspiracy Theorists

Ever since the 2012 Sandy Hook school shooting in Newtown, Connecticut, wild conspiracies have circulated claiming that the massacre was a hoax and a fraud. Twenty children and six adults were shot, and grieving families of the dead children have been accused of being paid actors in a scripted drama.

In the weeks and months following the Newtown shooting a loosely formed group of conspiracy theorists called the Sandy Hook Truther movement formed to promote evidence of what it claimed was a cover-up. The specific claims vary from person to person but typically suggest that the school shooting never happened — or if it did happen, it didn’t happen as described in the government’s “official story.”

In a “quest for truth” at a public board of education meeting earlier this week, conspiracy theorists took the opportunity to air their questions and complaints. According to an article in the Connecticut Post, “A dozen or so self-described skeptics of official accounts of the Sandy Hook Elementary School shooting appeared Tuesday night at the Board of Education meeting, each taking the allotted three minutes to address pointed questions to board members. Wolfgang Halbig, the most prominent member of the group, raised questions about everything from the scale of police response that day to their refusal to accept his expert help in analyzing the event. He suggested that his legitimate efforts to get answers have been thwarted, and accused board members of toeing an official line.”

The Board of Education, to their credit, refused to take the bait and completely ignored the conspiracy theorists. This is often an effective way to deal with conspiracy theories, since any response will be assumed to part of the “cover up” and thus a waste of time. Any contradictory evidence — no matter how conclusive or compelling — can be dismissed by claiming that it’s part of the cover-up. There is ultimately no evidence that would satisfy most conspiracy theorists, and responding to their claims merely gives them publicity and legitimacy.

Despite Halbig’s doubts about the “official story,” there is in fact no such thing as a single, homogenous “official story” about what happened at Sandy Hook; the narrative descriptions of what happened were composed of hundreds of local, state, and national officials, eyewitnesses, victims, members of various law enforcement agencies, hospital workers, dozens of independent journalists from various news outlets and so on. They all had different experiences, and it’s not as if they all came together to agree on one “official” undisputed version of events.

Conspiracy theorists spend weeks combing through news reports and accounts to find real or perceived inconsistencies and cite those as “evidence” of a conspiracy. Though the board wisely chose not to dignify Halbig’s questions with a response, others have assembled detailed, referenced responses answering his questions and debunking his claims.

The simple, undeniable fact is that the children killed in Newtown are gone, and they are not coming back. The Sandy Hook conspiracists would have us believe that the parents and families of the murdered children are part of some sinister scheme or “false flag” event to take away America’s gun rights, and that the “dead” children are really alive, presumably to be kept hidden away somewhere for the rest of their lives, or given false identities, or even killed by the government or abducted by aliens who crashed in Roswell and then escaped from Area 51. In the absence of evidence, one wild theory is as good as the next.

Harassment By Conspiracy Theorists

The First Amendment to the U.S. Constitution guarantees freedom of speech, and conspiracy promoters take full advantage of it. They are permitted to spread their claims in blogs, books, magazines, television shows and anywhere else they like, including public meetings. However conspiracy theorists typically do not want merely to have their ideas heard; they want them widely accepted as truth. They feel that they have an inside look at what really happened, and become angry and frustrated when they are unable to provide convincing evidence of their claims.

Similar harassment occurred in the wake of the theater massacre in Aurora, Colorado in July 2012 by alleged shooter James Holmes. According to an article on MSNBC, “Prosecutors say victims and witnesses in the Colorado theater shootings have been pestered by conspiracy theorists, impersonated in court filings and had their addresses and phone numbers posted online… prosecutors say some victims are concerned for their safety.” One conspiracy theorist was even arrested for stalking and harassment after repeatedly contacting relatives of the victims and telling them that their deaths were hoaxed, and that the coffins of their dead loved ones were buried empty.

Read more at Discovery News