Feb 1, 2014
The researchers recently reported their findings in Nature Communications.
"Converting carbon dioxide to useful chemicals in a selective and efficient way remains a major challenge in renewable and sustainable energy research," according to Feng Jiao, assistant professor of chemical and biomolecular engineering and the project's lead researcher.
Co-authors on the paper include Qi Lu, a postdoctoral fellow, and Jonathan Rosen, a graduate student, working with Jiao.
The researchers found that when they used a nano-porous silver electrocatalyst, it was 3,000 times more active than polycrystalline silver, a catalyst commonly used in converting carbon dioxide to useful chemicals.
Silver is considered a promising material for a carbon dioxide reduction catalyst because of it offers high selectivity -- approximately 81 percent -- and because it costs much less than other precious metal catalysts. Additionally, because it is inorganic, silver remains more stable under harsh catalytic environments.
The exceptionally high activity, Jiao said, is likely due to the UD-developed electrocatalyst's extremely large and highly curved internal surface, which is approximately 150 times larger and 20 times intrinsically more active than polycrystalline silver.
Jiao explained that the active sites on the curved internal surface required a much smaller than expected voltage to overcome the activation energy barrier needed drive the reaction.
The resulting carbon monoxide, he continued, can be used as an industry feedstock for producing synthetic fuels, while reducing industrial carbon dioxide emissions by as much as 40 percent.
To validate whether their findings were unique, the researchers compared the UD-developed nano-porous silver catalyst with other potential carbon dioxide electrocatalysts including polycrystalline silver and other silver nanostructures such as nanoparticles and nanowires.
Testing under identical conditions confirmed the non-porous silver catalyst's significant advantages over other silver catalysts in water environments.
Reducing greenhouse carbon dioxide emissions from fossil fuel use is considered critical for human society. Over the last 20 years, electrocatalytic carbon dioxide reduction has attracted attention because of the ability to use electricity from renewable energy sources such as wind, solar and wave.
Ideally, Jiao said, one would like to convert carbon dioxide produced in power plants, refineries and petrochemical plants to fuels or other chemicals through renewable energy use.
A 2007 Intergovernmental Panel on Climate Change report stated that 19 percent of greenhouse gas emissions resulted from industry in 2004, according to the Environmental Protection Agency's website.
Read more at Science Daily
Like the fictional Star Wars planet, Kepler-34(AB)b is a circumbinary planet, so-called because its orbit encompasses two stars. There are few environments more extreme than a binary star system in which planet formation can occur. Powerful gravitational perturbations from the two stars on the rocky building blocks of planets lead to destructive collisions that grind down the material. So, how can the presence of such planets be explained?
In research published this week in Astrophysical Journal Letters, Dr Zoe Leinhardt and colleagues from Bristol's School of Physics have completed computer simulations of the early stages of planet formation around the binary stars using a sophisticated model that calculates the effect of gravity and physical collisions on and between one million planetary building blocks.
They found that the majority of these planets must have formed much further away from the central binary stars and then migrated to their current location.
Dr Leinhardt said: "Our simulations show that the circumbinary disk is a hostile environment even for large, gravitationally strong objects. Taking into account data on collisions as well as the physical growth rate of planets, we found that Kepler 34(AB)b would have struggled to grow where we find it now."
Based on these conclusions for Kepler-34, it seems likely that all of the currently known circumbinary planets have also migrated significantly from their formation locations -- with the possible exception of Kepler-47 (AB)c which is further away from the binary stars than any of the other circumbinary planets.
Read more at Science Daily
Jan 31, 2014
Scientists have known for some time the location in the brain where speech sounds are interpreted, but little has been discovered about how this process works.
Now, in Science Express (January 30th, 2014), the fast-tracked online version of the journal Science, the UCSF team reports that the brain does not respond to the individual sound segments known as phonemes -- such as the b sound in "boy" -- but is instead exquisitely tuned to detect simpler elements, which are known to linguists as "features."
This organization may give listeners an important advantage in interpreting speech, the researchers said, since the articulation of phonemes varies considerably across speakers, and even in individual speakers over time.
The work may add to our understanding of reading disorders, in which printed words are imperfectly mapped onto speech sounds. But because speech and language are a defining human behavior, the findings are significant in their own right, said UCSF neurosurgeon and neuroscientist Edward F. Chang, MD, senior author of the new study.
"This is a very intriguing glimpse into speech processing," said Chang, associate professor of neurological surgery and physiology. "The brain regions where speech is processed in the brain had been identified, but no one has really known how that processing happens."
Although we usually find it effortless to understand other people when they speak, parsing the speech stream is an impressive perceptual feat. Speech is a highly complex and variable acoustic signal, and our ability to instantaneously break that signal down into individual phonemes and then build those segments back up into words, sentences and meaning is a remarkable capability.
Because of this complexity, previous studies have analyzed brain responses to just a few natural or synthesized speech sounds, but the new research employed spoken natural sentences containing the complete inventory of phonemes in the English language.
To capture the very rapid brain changes involved in processing speech, the UCSF scientists gathered their data from neural recording devices that were placed directly on the surface of the brains of six patients as part of their epilepsy surgery.
The patients listened to a collection of 500 unique English sentences spoken by 400 different people while the researchers recorded from a brain area called the superior temporal gyrus (STG; also known as Wernicke's area), which previous research has shown to be involved in speech perception. The utterances contained multiple instances of every English speech sound.
Many researchers have presumed that brain cells in the STG would respond to phonemes. But the researchers found instead that regions of the STG are tuned to respond to even more elemental acoustic features that reference the particular way that speech sounds are generated from the vocal tract. "These regions are spread out over the STG," said first author Nima Mesgarani, PhD, now an assistant professor of electrical engineering at Columbia University, who did the research as a postdoctoral fellow in Chang's laboratory. "As a result, when we hear someone talk, different areas in the brain 'light up' as we hear the stream of different speech elements."
"Features," as linguists use the term, are distinctive acoustic signatures created when speakers move the lips, tongue or vocal cords. For example, consonants such as p, t, k, b and d require speakers to use the lips or tongue to obstruct air flowing from the lungs. When this occlusion is released, there is a brief burst of air, which has led linguists to categorize these sounds as "plosives." Others, such as s, z and v, are grouped together as "fricatives," because they only partially obstruct the airway, creating friction in the vocal tract.
The articulation of each plosive creates an acoustic pattern common to the entire class of these consonants, as does the turbulence created by fricatives. The Chang group found that particular regions of the STG are precisely tuned to robustly respond to these broad, shared features rather than to individual phonemes like b or z.
Read more at Science Daily
Wolves were domesticated more than 15,000 years ago and it is widely assumed that the ability of domestic dogs to form close relationships with humans stems from changes during the domestication process. But the effects of domestication on the interactions between the animals have not received much attention. The point has been addressed by Friederike Range and Zsófia Virányi, two members of the University of Veterinary Medicine, Vienna (Vetmeduni Vienna) who work at the Wolf Science Center (WSC) in Ernstbrunn, Niederösterreich.
Wolves copy other wolves solving problems
The scientists found that wolves are considerably better than dogs at opening a container, providing they have previously watched another animal do so. Their study involved 14 wolves and 15 mongrel dogs, all about six months old, hand-reared and kept in packs. Each animal was allowed to observe one of two situations in which a trained dog opened a wooden box, either with its mouth or with its paw, to gain access to a food reward. Surprisingly, all of the wolves managed to open the box after watching a dog solve the puzzle, while only four of the dogs managed to do so. Wolves more frequently opened the box using the method they had observed, whereas the dogs appeared to choose randomly whether to use their mouth or their paw.
Watch closely …
To exclude the possibility that six-month old dogs fail the experiment because of a delayed physical or cognitive development, the researchers repeated the test after nine months. The dogs proved no more adept at opening the box than they were at a younger age. Another possible explanation for the wolves' apparent superiority at learning is that wolves might simply be better than dogs at solving such problems. To test this idea, the researchers examined the animals' ability to open a box without prior demonstration by a dog. They found that the wolves were rarely successful. "Their problem-solving capability really seems to be based on the observation of a dog performing the task," says Range. "The wolves watched the dog very closely and were able to apply their new knowledge to solve the problem. Their skill at copying probably relates to the fact that wolves are more dependent on cooperation with conspecifics than dogs are and therefore pay more attention to the actions of their partners."
Read more at Science Daily
The fossils, described in the latest issue of the Journal of Mammalian Evolution, date to that early period and belonged to a scrappy canine carnivore known as Canis etruscus that lived near Rome, Italy.
"Canis etruscus appeared approximately 2 million years ago and is the oldest European species referred to in the genus Canis," lead author Marco Cherin told Discovery News, adding that this species "was considerably smaller than the modern wolf."
"We can suppose that it was a social dog, as most of the living species of similar size," continued Cherin, who is a researcher at Perugia University's Department of Earth Sciences. "Hunting in packs, Canis etruscus could have preyed on small to medium-sized animals."
The prey of this carnivore, which looked like a cross between a German shepherd and a wolf, would have included animals such as ancient relatives of deer and pigs. They were all common at the site: Pantalla, Italy.
This apparent mother of all dogs in Europe likely gave rise to another member of the dog/wolf family tree, Canis mosbachensis, about 1 million years ago. Canis mosbachensis, in turn, is considered to be a direct ancestor of modern wolves.
Until recently, it was thought that dogs were domesticated from the gray wolf, but a separate study earlier this month countered that popular belief.
"The common ancestor of dogs and wolves was a large, wolf-like animal that lived between 9,000 and 34,000 years ago," Robert Wayne of UCLA, who was co-senior author of the study, told Discovery News.
That animal went extinct thousands of years ago and, as of now, remains unknown.
Canines spread to Asia and then to Europe. It was in Eurasia at least 780,000 years ago that a dog relative might have encountered a member of our genus.
Eudald Carbonell, a professor at the University of Rovira and Virgili, told Discovery News that fossils of Homo antecessor -- an extinct human that looked a lot like us -- were found with fossils of Canis mosbachensis in Spain.
Could this very early human have enjoyed the companionship of the dog/wolf relative, or was the latter considered to be good eats or a predator? The fossil record so far, unfortunately, does not have those answers.
Carbonell and his team did find evidence for cannibalism -- for nutritional purposes -- among Homo antecessor individuals, so it's likely that this early, hungry human hunted the dog and wolf relative.
Read more at Discovery News
The monster frog, Beelzebufo ampinga, lived during the Cretaceous Period in what is now Africa, and sported spiky flanges protruding from the back of its skull and platelike armor down its back, almost like a turtle shell.
"We knew it was big; we knew it was almost certainly predatory," said study co-author Susan Evans, a paleontologist at the University College London. "What the new material has shown us is that it was even more heavily armored than we imagined."
The massive frog's spiked body armor may have helped it fend off the dinosaurs and crocodiles that prowled during that time.
The researchers first discovered a few bone fragments from a mystery frog in Madagascar in 1998, but it wasn't until 2008 that they had enough pieces to identify the species, which they dubbed the devil frog, or Beelzebufo ampinga. The massive frog lived between 70 million and 65 million years ago.
When the team analyzed the frog's morphology, they found that physically, it fit in with a family of horned frogs called the Ceratophryidae, which are now found only in South America.
But to reach Madagascar from South America, the frogs would have needed to hop along a passageway, possibly through Antarctica, that linked the two landmasses. But that route was submerged underwater by 112 million years ago, Evans said.
That would mean that devil frogs must have diverged from their South American cousins prior to that submergence, pushing back the origin of Ceratophryidae by more than 40 million years, Evans said.
Over the course of the next five years, the team found several more bone fragments of Beelzebufo ampinga. In the new study, they combined all of the fragments to do a much more complete reconstruction of the devil frog.
The new analysis confirms the frog's lineage in the Ceratophryidae family. It also downgrades the amphibian's size -- instead of being the biggest frog that ever lived, it may be closer to the size of an African bullfrog, which grows to about 10 inches (25.4 centimeters) across.
Even so, the analysis reveals that the devil frog was even fiercer-looking than previously thought. Past studies had suggested it had a huge, globular head; sharp teeth; and short back legs, but the spiky flanges and the plates embedded in its skin were a surprising discovery.
The frogs may have hunted like African bullfrogs, hiding before pouncing on a small mammal.
It's not clear what the frogs used the body armor for, but one possibility is that the sculptured bones may have been an adaptation to a dry environment that allowed the frogs to burrow underground, where they were less likely to bake in the hot sun, Evans said.
Read more at Discovery News
Jan 30, 2014
A team led by University of Pennsylvania paleontologists has characterized a new dinosaur based on fossil remains found in northwestern China. The species, a plant-eating sauropod named Yongjinglong datangi, roamed during the Early Cretaceous period, more than 100 million years ago. This sauropod belonged to a group known as Titanosauria, members of which were among the largest living creatures to ever walk the earth.
At roughly 50-60 feet long, the Yongjinglong individual discovered was a medium-sized Titanosaur. Anatomical evidence, however, points to it being a juvenile; adults may have been larger.
The find, reported in the journal PLOS ONE, helps clarify relationships among several sauropod species that have been found in the last few decades in China and elsewhere. Its features suggest that Yongjinglong is among the most derived, or evolutionarily advanced, of the Titanosaurs yet discovered from Asia.
Doctoral student Liguo Li and professor Peter Dodson, who have affiliations in both the School of Veterinary Medicine's Department of Animal Biology and the School of Arts and Sciences' Department of Earth and Environmental Science, led the work. They partnered with Hailu You, a former student of Dodson's, who now works at the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology, and Daqing Li of the Gansu Geological Museum in Lanzhou, China.
Until very recently, the United States was the epicenter for dinosaur diversity, but China surpassed the U.S. in 2007 in terms of species found. This latest discovery was made in the southeastern Lanzhou-Minhe Basin of China's Gansu Province, about an hour's drive from the province's capital, Lanzhou. Two other Titanosaurs from the same period, Huanghetitan liujiaxiaensis and Daxiatitan binglingi, were discovered within the last decade in a valley one kilometer from the Yongjinglong fossils.
"As recently as 1997 only a handful of dinosaurs were known from Gansu," Dodson said. "Now it's one of the leading areas of China. This dinosaur is one more of the treasures of Gansu."
During a trip to Gansu, Liguo Li was invited to study the remains, which had been in storage since being unearthed in 2008. They consisted of three teeth, eight vertebrae, the left shoulder blade, and the right radius and ulna.
The anatomical features of the bones bear some resemblance to another Titanosaur that had been discovered by paleontologists in China in 1929, named Euhelopus zdanskyi. But the team was able to identify a number of unique characteristics.
"The shoulder blade was very long, nearly 2 meters, with sides that were nearly parallel, unlike many other Titanosaurs whose scapulae bow outward," Li said.
The scapula was so long, indeed, that it did not appear to fit in the animal's body cavity if placed in a horizontal or vertical orientation, as is the case with other dinosaurs. Instead, Li and colleagues suggest the bone must have been oriented at an angle of 50 degrees from the horizontal.
In addition, an unfused portion of the shoulder blade indicated to the researchers that the animal under investigation was a juvenile or subadult.
"The scapula and coracoid aren't fused here," Li said. "It is open, leaving potential for growth."
Thus, a full-grown adult might be larger than this 50-60 foot long individual. Future finds may help elucidate just how much larger, the researchers noted.
The ulna and radius were well preserved, enough so that the researchers could identify grooves and ridges they believe correspond with the locations of muscle attachments in the dinosaur's leg.
The researchers were also able to draw evidence about the dinosaur's relationship to other species from the vertebrae, one of which was from the neck and the other seven from the trunk. Notably, the vertebrae had large cavities in the interior that the team believes provided space for air sacs in the dinosaur's body.
"These spaces are unusually large in this species," Dodson said. "It's believed that dinosaurs, like birds, had air sacs in their trunk, abdominal cavity and neck as a way of lightening the body."
In addition, the longest tooth they found was nearly 15 centimeters long. Another shorter tooth contained unique characteristics, including two "buttresses," or bony ridges, on the internal side, while Euhelopus had only one buttress on its teeth.
To gain a sense of where Yongjinglong sits on the family tree of sauropods, the researchers were able to compare its characteristics with specimens from elsewhere in China, as well as from Africa, South America and the U.S.
"We used standard paleontological techniques to compare it with phylogenies based on other specimens," Dodson said. "It is definitely much more derived than Euhelopus and shows close similarities to derived species from South America."
Read more at Science Daily
|Giant African land snails carry quarters with them everywhere they go in case they need to, like, use payphones and stuff.|
This actually happened in the 1960s, when a boy vacationing with his family in Hawaii had pocketed a few giant African land snails (Lissachatina fulica), a mollusk that grows to a foot long and a full pound. Hawaii had been battling the pest, and so too would Florida, where the boy returned with his new friends. Once home, he quickly grew bored of the snails and handed them over to his grandmother, who set them free in her backyard.
What ensued was an invasion by rapidly reproducing critters that have over the last century spread out of their native East Africa into tropical climes all over the world, from Asia to South America, as stowaways on ships or as pets brought home by people with a thing for snails. In Florida, eradication took seven years. Other places, like Brazil, have not been so lucky in their efforts.
You see, the giant African land snail is a hermaphroditic love machine. “Snails have female bits and male bits,” explained biologist Robert Cowie of the University of Hawaii, “a single pore, through which if you’re acting as a male, a penis extrudes, or if you’re acting as a female, through which the other snail puts its penis in. And in some cases they can do it reciprocally.”
Thus the giant snail never meets another snail it can’t get busy with. Once fertilized, the snail will bury several hundred eggs a few inches below ground, and because of the incredible size of the species, the young will emerge far larger than native varieties, making them that much more resistant to predation.
|As these eggs demonstrate, cash rules everything around the giant snails from a very early age.|
The USDA and U.S. District Attorney’s Office are investigating this. It probably doesn’t help the ritualists’ case, though, that the year before the current outbreak, authorities questioned a Florida man said to have convinced his followers to drink the fluid from live giant African land snails, which he sliced open before squeezing the slime into their mouths. If you can believe it, the victims fell violently ill — ironic, what with this being a healing ritual.
Anyway, if it was indeed the practitioners who released the snails so they (the snails, not the practitioners) could multiply rapidly, it worked. Big time. Florida agriculture officials have collected 137,000 giant snails in just over two years. Compare that to the relatively few 17,000 collected in the first eradication in the 1960s, and you soon see the magnitude of this problem.
Today, Miami is simply overrun with the things. Not only do the giant snails chow on some 500 economically important plants in the area, they’re devouring houses. It seems they have a taste for stucco, which contains precious calcium. Without a ready supply of the stuff to fuel their amazing growth, they’ll simply turn on each other — at least in captivity.
|You may be getting the impression that the giant snail’s natural habitat is the human hand. It is.|
And because I know you were wondering: Yes, you can eat giant African land snails. But cook them well. I mean really well. Just boil them for a month. Grill them with napalm if you have it. Because like many snails and semi-slugs, this species carries the deadly rat lungworm.
As its name suggests, the parasite attacks rats, which pass the larvae in their feces. Snails that eat this waste are infected, as are folks who eat the snails. In humans, the larvae attack the brain, leading to meningitis and often a pretty horrible death. This has been documented as a particular problem in China, where people may not be cooking giant snails sufficiently.
But for all the folks who cook their giant snails properly, still others ingest them accidentally. All manner of critters could very easily end up in your Caesar salad, for instance, since cooks don’t always peel apart the lettuce before chopping it. “And it could just as well be a little baby African snail,” said Cowie. “OK, it’s a bit crunchy, but so is the lettuce a bit crunchy, and you’d never know. So that’s the way people generally get infected in places where they don’t habitually eat raw snails.”
|The giant snail’s shell can grow to 8 inches long. To grow such a home, it eats the calcium-rich stucco from our own homes. There’s some sort of symbolism there, but I can’t figure it out.|
By deploying common over-the-counter snail poison and advertising a hotline residents can call to report sightings, authorities have so far been able to contain the critter to Miami. And no, pouring salt on them is in no way an acceptable option for homeowners. It’s a horrible death. Osmosis pulls the water out of the snail, killing it of dehydration. Just don’t do it. Ever.
But it’s possible, according to Cowie, that the giant snail could well spread to other Gulf states, though luckily they probably can’t tolerate the cooler weather in Georgia and other states farther north (contrary to popular belief, Hotlanta is not in fact always hot — most of the time it’s just Atlanta).
Cowie knows all too well the explosive population growth these things are capable of when left unchecked. In Hawaii, where he lives, the giant African land snail was introduced in the 1930s by Japanese immigrants who wanted to keep them as pets. They have since essentially assumed ecological control, tearing through agriculture and muscling out native species.
Read more at Wired Science
The study, published in the latest Journal of Experimental Biology, helps to explain how such snakes (in the genus Chrysopelea) can remain airborne for up to 100 feet in their Southeast Asia rainforest habitats.
The snakes launch from seemingly any position on a tree, flexing their ribs as they initiate a glide. They then stretch and flatten their bodies from a circle into an arched semi-circle.
“It looks like someone’s version of a UFO,” co-author Jake Socha of Virginia Tech’s College of Engineering, said in a press release.
The snakes launch themselves into air to move around their treetop home and to escape predators. They are mildly venomous, and prefer to take flight rather than fight.
For the study, Socha and his colleagues first watched the snakes in action. From afar, the snakes appear to be slithering midair.
“They look like they are swimming,” he said. “They turn their whole body into one aerodynamic surface.”
To determine what’s going on up close, the researchers used a 3-D printer to produce a rod with the same cross-section as the snake’s body. They then placed it across a tank filled with water that flowed over the snake-shaped bar.
Socha explained that, although water is much denser than air, it was possible for he and his colleagues to precisely recreate the air conditions experienced as the snakes fly. They flowed water over the model at a specific range of speeds. Those speeds ranged from about 8 to 20 inches per second.
Slightly tilting the snake model revealed that, at most angles, the snake’s body generated sufficient lift to account for the impressive gliding. When the rod was flat, however, turbulence created a suction-like force on the snake model, pulling it downward.
“Maybe the snake does hold part of its body flat at some point, using it as a mechanism for control,” Socha said, explaining that twisting the body while airborne could allow the snakes to fine tune the forces on their bodies for precise flight control.
The model, however, does not fully explain how snakes use their long bodies to stay airborne for so long.
Read more at Discovery News
It might seem a purely hypothetical question but astronomers have actually managed to directly observe “weather” on a brown dwarf, using the incredible imaging power of the European Southern Observatory’s Very Large Telescope (VLT) located on the Cerro Paranal mountain in Chile’s Atacama desert.
Changing patterns of dark and light regions have been observed moving around the brown dwarf as it rotates — similar to what might be seen on a gas giant planet like Jupiter or Saturn.
“Previous observations suggested that brown dwarfs might have mottled surfaces, but now we can actually map them,” said Ian Crossfield from the Max Planck Institute for Astronomy, the lead author of these findings. “Soon, we will be able to watch cloud patterns form, evolve, and dissipate on this brown dwarf — eventually, exometeorologists may be able to predict whether a visitor to Luhman 16B could expect clear or cloudy skies.”
Since brown dwarfs are a kind of missing link between the coolest stars and the most massive “hot Jupiters,” learning how to accurately observe their changing weather will help astronomers be able to do the same on actual exoplanets.
Read more at Discovery News
Jan 29, 2014
Ancient teeth have given scientists the material to confirm the exact bacteria strain that caused the plague by reconstructing its DNA. Finding the teeth was key: when housing developers accidentally uncovered a burial site outside of Munich, archaeologists confirmed that the graves dated to the time of the plague.
“They found some that had multiple individuals buried together, which is often times indicative of an infectious disease,” Northern Arizona University evolutionary biologist David Wagner told National Public Radio. “And so in this particular case, we examined material from two different victims. One of those victims was buried together with another adult and a child, so it’s presumed that they all may have died of the plague at the same time.”
The dental pulp inside their teeth contained enough traces of blood to find the DNA of the plague bacteria.
After sequencing the DNA, scientists were able to track the spread of the disease. They think the bacteria started in China, jumping from rodents to humans — and that it wasn’t related to the Black Death, as was previously believed.
“These results show that rodent species worldwide represent important reservoirs for the repeated emergence of diverse lineages of Y pestis into human populations,” the authors wrote in The Lancet Infectious Diseases.
Read more at Discovery News
The genetic material inherited from Neanderthals combined with that of humans when the two species interbred 40,000 to 80,000 years ago, the study holds. The research further supports that indigenous Africans possess little or no Neanderthal DNA because their ancestors did not breed with Neanderthals, which lived in Europe and Asia.
It now appears that mating between the two species was much more prevalent than was previously suspected.
Some genetic mutations introduced by Neanderthals were not beneficial to humans. Neanderthals' contribution to modern DNA was partially removed by natural selection over time.
“Given the large amount of Neanderthal alleles (gene variants) that were swept away by selection, we think that there was a larger fraction of Neanderthal ancestry initially,” lead author Sriram Sankararaman explained to Discovery News, adding that “we think that this ancestry was reduced by a third.”
Sankararaman, a post-doctoral researcher at Harvard Medical School’s Department of Genetics, co-authored the paper with leading evolutionary geneticists, such as Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology and Harvard’s David Reich.
The researchers analyzed genetic variants in 846 people of non-African heritage, 176 people from sub-Saharan Africa and a 50,000-year-old Neanderthal.
The clearest indicator that a gene variant came from a Neanderthal was if the variant appeared in some non-Africans and the Neanderthal, but not in the sub-Saharan Africans.
Levels of Neanderthal ancestry differ in European and Asian groups, according to the study. Han Chinese people in Beijing, for example, have the most such ancestry while Puerto Ricans have the least.
All Europeans and Asians, however, retain Neanderthal genes affecting keratin, which is a fibrous protein in skin and hair. Reich explained that keratin makes skin, hair and nails tougher and better able to withstand cold temperatures.
“It’s tempting to think that Neanderthals were already adapted to the non-African environment and provided this genetic benefit to humans,” Reich said.
It's possible that the lighter skin and hair of many Europeans was also influenced by Neanderthal ancestry, but Sankararaman indicated that further research is needed to fully make that connection.
The study additionally found that genetic variants passed down from Neanderthals also affect an individual’s disposition toward type 2 diabetes, Crohn’s disease, lupus, a liver condition known as biliary cirrhosis and even whether a person is likely to smoke.
X chromosome-related genetic mutations from Neanderthals, along with DNA associated with male sexual organs, were more likely to have been incompatible with the human genome. These were less easily exchanged between the two species. People who still retain such Neanderthal DNA, like East Asians, experience reduced fertility as a probable result.
“This suggests that when ancient humans met and mixed with Neanderthals, the two species were at the edge of biological incompatibility,” Reich said.
Read more at Discovery News
Previous observations of the 2,000 or so biggest asteroids in the belt -- those with diameters of roughly 100 kilometers (62 miles) or larger -- showed a neat structure, with asteroids closer to the sun having surface temperatures warmer than those located farther away.
The observations neatly match theories about the formation of the solar system, which posits that bodies formed in warm environments would be found closer to the sun and those formed in cold environments are farther away.
"We said, 'Oh look, this has been preserving the conditions from the original formation. Case closed. It all makes sense,'" astronomer Francesca DeMeo, with the Harvard-Smithsonian Center for Astrophysics, told Discovery News.
But a new analysis, this time based on 100,000 asteroids of varying sizes, tells a far different story.
"Everything is mixed. Pieces are everywhere, like they’ve been just kind of thrown all over the asteroid belt," said DeMeo, lead author of a study that appears in this week’s journal Nature.
"It’s certainly overturned a lot of traditional thinking," added University of Arizona planetary scientist Dante Lauretta, lead researcher for an upcoming NASA asteroid sample return mission.
"There is still an underlying structure and composition, but there is evidence of mixing and that just makes so much sense to me," he said.
Scientists don’t yet know why smaller asteroids buck the trend of their larger siblings, but that it is related to the gravitational elbowing by jostling planets early in the solar system’s history.
"What we’re leaning toward now is that asteroids, rather than forming in the asteroid belt, formed throughout the entire solar system ... as close (to the sun) as Mercury and as far away as Neptune, and then, through the planetary migration, you scatter them all over the place. What’s left is what you see in the asteroid belt today," DeMeo said.
Read more at Discovery News
Clouds of gas, by their nature, are diffuse and difficult to detect. Often, we can see gas that lies along a line of sight to distant bright object, such as a quasar. However, that only gives insight into one small piece of that cloud.
A quasar is the bright central region of a galaxy that is being powered by a supermassive black hole that is gobbling up surrounding material. A team of astronomers, with lead author Sebastiano Cantalupo, looked towards such a quasar 10 billion light years away and found it illuminating a gas cloud far too large to be part of a galaxy cluster.
This gas resides in the intergalactic medium, the spaces between galaxies. It is two million light years across, a distance equal to roughly the distance between the Milky Way Galaxy and the Andromeda Galaxy. It was detected in the faint glow given off by hydrogen atoms that were excited by the radiation of the nearby quasar using the 10-meter Keck I telescope in Hawaii.
This cosmic web is not only poetic but important to the formation of galaxies and galaxy clusters. According to the Millennium Simulation, these filaments help to funnel gas into the “nodes” of the web, the sites of large galaxies and galaxy clusters. Our Milky Way Galaxy is thought to have formed in a small such node in this web.
Much of the material, over 80 percent, is dark matter, or matter that does not directly interact with electromagnetic radiation. Although we’ve detected its presence indirectly for decades due to its gravitational effects, we are no at the point where dark matter in the cosmos has been thoroughly mapped out. This gas, the “normal” matter that makes up people, stars, and planets, however, can be seen.
Since it is so diffuse, this gas proved to be a challenging target. It was found near a quasar in part because the quasar made it glow. It is also an ideal place for searching for such gas because quasars tend to inhabit the more densely populated nodes of the web, thus are likely to be surrounded by more of these filaments.
Read more at Discovery News
Jan 28, 2014
The first ever Greenlandic reef is located in southwest Greenland and was formed by cold-water corals with hard limestone skeletons. There are several species of coral in Greenland, but this is the first time that an actual reef has been found.
In the tropics, reefs are popular tourist destination for divers, but there is little prospect of Greenland becoming a similar diving hotspot. The newly discovered living reef is located off Cape Desolation south of Ivittuut, and lies at a depth of 900 metres in a spot with very strong currents, making it difficult to reach. This also means that so far little is known about the reef itself and what lives on it
The reef was discovered by accident when a Canadian research vessel needed to take some water samples. When the ship sent the measuring instruments down to a depth of 900 metres, they came back up completely smashed. Fortunately there were several pieces of broken coral branches on the instrument that showed what was responsible.
"At first the researchers were swearing and cursing at the smashed equipment and were just about to throw the pieces of coral back into the sea, when luckily they realized what they were holding," says PhD student Helle Jørgensbye, DTU Aqua, who does research into life at the bottom of the west Greenland waters.
The first photos
Another Canadian research vessel returned to the site last fall to try and lower a camera down onto the reef to explore it close up. The coral reef is on the continental shelf itself where it is very steep and where there are strong currents.
"We got some photos eventually, although we almost lost them at the bottom of the ocean as the camera got stuck fast somewhere down in the depths. Luckily we managed to get it loose again and back up to the surface," says Helle Jørgensbye.
"It's been known for many years that coral reefs have existed in Norway and Iceland and there is a lot of research on the Norwegian reefs, but not a great deal is known about Greenland. In Norway, the reefs grow up to 30 metres high and several kilometres long. The great Norwegian reefs are over 8,000 years old, which means that they probably started to grow after the ice disappeared after the last ice age. The Greenlandic reef is probably smaller, and we still don't know how old it is," says Helle Jørgensbye, expressing the hope that at some point this will be investigated more closely.
According to Helle Jørgensbye, finding a coral reef in southern Greenland was not entirely unexpected:
"There are coral reefs in the countries around Greenland and the effect of the Gulf Stream, which reaches the west coast, means that the sea temperature get up to about 4 degrees, which is warm enough for corals to thrive. In addition to the, for Greenland, comparatively warm temperature, a coral reef also needs strong currents. Both these conditions can be found in southern Greenland," she says.
Coral reefs are important areas for fish because it provides masses of food and lots of hiding places for fish fry. The Greenlandic reef is formed from Lophelia stoney corals. Other species of coral are also found in many parts of the west coast. However, they are all 'stand-alone' corals and do not form reefs. The identification of the Lophelia specimen was carried out by Professor Ole Tendal from Denmark's Natural History Museum.
Read more at Science Daily
In the second season of the BBC's hit show "Sherlock," shadowy snipers threaten the eponymous detective's friends by skulking around stairwells with high-powered rifles or infiltrating their homes and workplaces.
In real life, targets of assassination in Britain are more likely to be killed while walking their dogs or going shopping, new research finds.
The study of contract killings spanning from 1974 to 2013, published in The Howard Journal of Criminal Justice, finds that assassinations are often rather mundane.
"Hit men are familiar figures in films and video games, carrying out 'hits' in underworld bars or from the rooftops with expensive sniper rifles," David Wilson, a criminologist Birmingham City University's Center for Applied Criminology, said in a statement. "The reality could not be more different."
The four types of hit men
Wilson and his colleagues were interested in studying contract killing, in which someone pays another person to carry out a murder. These types of killings are rarely studied, the researchers said.
They combed through newspaper archives for examples of hits in Britain and found evidence of 27 murders carried out by 35 hit men — and one hit woman. They also used court transcripts and interviews with offenders to find out details such as how much killers had been paid.
The results revealed a wide variety of ages and expertise in killing. Hit men were as young as 15 and as old as 63, with an average age of 38. There were four types of hit men: Novices, who were caught after their first murder; dilettantes, who are the least likely to have a criminal background and may lack enthusiasm for killing; journeymen, who are career criminals but not particularly stealthy; and masters.
Masters are the least likely to be caught, Wilson and his colleagues found. They often have a military or paramilitary background, and are successful because they have few local ties. Journeymen, in contrast, may be good at killing, but their criminal connections often give them away to police.
Motives for murder
The cost of a hit varies widely as well, the researchers found. The cheapest kill, in 2010, cost 200 British pounds ($331.72 in today's U.S. dollars), paid to Santre Sanchez Gayle, a 15-year-old, for killing 26-year-old Gulistan Subasi. Gayle was a "novice" hit man who was caught because he bragged about the killing later.
The highest fee for a contract killing was 100,000 pounds ($165,860 in today's U.S. dollars). The only female contract killer in the study, a New Zealander named Te Rangimaria Ngarimu, charged 7,000 pounds ($11,610 in today's dollars) to kill the business partner of two men who hired her from prison in 1992. According to news reports about her trial, she only received about one-seventh that amount.
One "dilettante" hit man, Orville Wright, became known as the hit man who lost his nerve. Wright was sentenced to two years in prison in 1998 after he threatened to kill a London woman at the behest of her ex-boyfriend. After breaking into the woman's flat and talking to her, Wright was unable to go through with the murder.
The tales hint at how pedestrian most contract killings are. While television hits usually involve shady conspiracies or megalomaniac masterminds, real contract kills are far less melodramatic.
Read more at Discovery News
A newly discovered hearth full of ash and charred bone in a cave in modern-day Israel hints that early humans sat around fires as early as 300,000 years ago — before Homo sapiens arose in Africa.
In and around the hearth, archaeologists say they also found bits of stone tools that were likely used for butchering and cutting animals.
The finds could shed light on a turning point in the development of culture "in which humans first began to regularly use fire both for cooking meat and as a focal point -- a sort of campfire -- for social gatherings," said archaeologist Ruth Shahack-Gross of the Weizmann Institute of Science in Israel.
"They also tell us something about the impressive levels of social and cognitive development of humans living some 300,000 years ago," Shahack-Gross added in a statement.
The centrally located fire pit is about 6.5 feet (2 meters) in diameter at its widest point, and its ash layers suggest the hearth was used repeatedly over time, according to the study, which was detailed in the Journal of Archaeological Science on Jan. 25.
Shahack-Gross and colleagues think these features indicate the hearth may have been used by large groups of cave dwellers. What's more, its position implies some planning went into deciding where to put the fire pit, suggesting whoever built it must have had a certain level of intelligence.
Qesem Cave was discovered more than a decade ago during the construction of a road some 7 miles (11 kilometers) east of Tel Aviv. At the site, excavators had previously uncovered other traces of fire (scattered deposits of ash and clumps of soil that had been heated to high temperatures) as well as the butchered bones of big game like deer, aurochs and horse left their by the prehistoric cave dwellers, possibly up to 400,000 years ago.
Anthropologists have debated what constitutes the earliest evidence of controlled fire use -- and which hominin species was responsible for it. Ash and burnt bone in Wonderwerk Cave in South Africa suggests human ancestors used fire at least 1 million years ago.
Some researchers, meanwhile, have speculated that the teeth of Homo erectus suggest this early human was adapted to eat food cooked over a fire by 1.9 million years ago. A study out last year in the Cambridge Archaeological Journal argued that fire-builders would have needed some sophisticated abilities to keep their hearths burning, such as long-term planning (gathering firewood) and group cooperation.
It's not entirely clear who was cooking at Qesem Cave. A study published about three years ago in the American Journal of Physical Anthropology described teeth found in the cave dating to between 400,000 and 200,000 years ago. The authors speculated the teeth might have belonged to modern humans (Homo sapiens), Neanderthals or perhaps a different species, though they noted they couldn't draw a solid conclusion from their evidence.
Nonetheless, study researcher Avi Gopher, an archaeologist from Tel Aviv University, said in an interview with Nature at the time, "The best match for these teeth are those from the Skhul and Qafzeh caves in northern Israel, which date later [to between 80,000 and 120,000 years ago] and which are generally thought to be modern humans of sorts."
Read more at Discovery News
Washing hands and taking zinc may be the best ways to avoid getting the common cold, and over-the-counter pain relievers are the recommended treatments to alleviate the symptoms, according to a new review.
The common cold strikes adults two to three times a year on average, while children under age 2 develop colds about six times a year, according to the study. There's no vaccine or cure for the cold, which usually takes only a few days to resolve on its own but can be bothersome and debilitating.
To identify the best ways to prevent getting a cold, or help alleviate its symptoms once it has struck, researchers reviewed more than 150 studies of both traditional and nontraditional approaches, ranging from gargling water to eating garlic. They detailed their findings today (Jan. 27) in the Canadian Medical Association Journal.
The best way to avoid a cold is to keep your hands germ-free, according to the study. The researchers reviewed 67 randomized, controlled trials looking at cold prevention, and concluded that regularly washing the hands, as well as using alcohol-based disinfectants and gloves, are likely effective in preventing the cold.
Taking zinc works, too. This element is found in meat, beans and nuts, and appears to be effective in reducing the number of colds per year, at least in children, the researchers said. In studies, children who took 10 to 15 milligrams of zinc sulfate daily had fewer colds than children taking a placebo. Although these studies involved only children, there is no biological reason why zinc would not work similarly in adults, the researchers said.
There is some evidence that probiotics may help prevent colds, although the types and combinations of organisms varied in the studies, as did the formulations (for example, pills or liquids), making comparison difficult, the researchers said.
Studies of other measures — including gargling water, eating garlic, exercising and homeopathic remedies — didn't provide clear or sufficient evidence that these methods are beneficial, the researchers said.
The pain relievers ibuprofen and acetaminophen are effective in relieving pain and fever, but not in relieving other symptoms, the researchers found. Ibuprofen appears to work better than acetaminophen in treating fever in children.
Taking antihistamines combined with decongestants or pain medications appears to be somewhat effective in treating the symptoms of colds in people older than age 5, according to the study.
Read more at Discovery News
Jan 27, 2014
Infant girls were apparently not killed more often than baby boys, researchers report in an upcoming issue of the Journal of Archaeological Science.
"Very often, societies have preferred male offspring, so when they practice infanticide, it tends to be the male babies that are kept, and the female babies that are killed," said study researcher Simon Mays, a skeletal biologist for English Heritage, a non-governmental organization that protects historic sites.
Though ancient Romans indeed preferred boys, there is no evidence they went as far as infanticide to skew the sex ratio, Mays told LiveScience.
Mays and his colleagues used a technique called ancient DNA analysis to study infant bones found at a site called Yewden Villa, near Hambleden, in England. Although the site was first excavated in 1912, and found to hold the remains of infants dating back about 1,800 years, the infant bones were since thought to have been lost, Mays said.
But recently, nearly a century after the initial excavation, archaeologist Jill Eyers, director of Chiltern Archaeology in England, found the bones tucked away in tiny boxes in the site archive.
In 2011, Mays and Eyers published a study of the bones suggesting the babies were victims of infanticide, based on the fact that measurements of the long bones of the arms and legs suggested that all of the babies died at the same age, right at the time of birth.
If the deaths had been natural, Mays said, you'd expect to see some premature babies, some who died around the time of birth, and others who died in the weeks after birth.
Because of the high number of skeletons, the researchers speculated the site contained a brothel, and the babies were those of prostitutes. But that idea was always "a long shot," Mays said.
In the new study, the researchers delved into why these babies were killed. Ancient Roman texts refer to infanticide as an accepted practice, and the only way people could control the size of their families in a time before reliable contraception. (In fact, Rome's foundation myth involves twin boys, Romulus and Remus, who are left to die by their mother, but are saved by wild animals.)
The texts refer to infanticide in Rome itself, however, which had a different culture than its far-flung territories, such as those in Britain, Mays said.
And although the Roman preference for boys would suggest that Romans practiced sex-selective infanticide, Mays said, there is only one document to back up that assumption — a letter from one Roman soldier stationed in England to his pregnant wife, telling her not to bother keeping the baby if it's a girl when it's born.
It's impossible to tell the sex of a baby by looking at the shape of the bones. Sex differences only emerge after puberty, Mays said. So the researchers turned to a newer tool: ancient DNA analysis. They tested 33 of the 35 most complete remains, but because DNA does not preserve well in old bones, the researchers were able to tease out sequences for only 12 of the 33.
Of those, seven were female and five were male, a relatively even sex ratio, Mays said.
What's more, none of the babies shared a mother, a strike against the brothel hypothesis. If the babies were the offspring of prostitutes, Mays said, the women would likely have been pregnant again and again.
The 12 babies studied in the new paper bring the total number of ancient Roman babies thought to be victims of infanticide who have undergone DNA testing to 25. Overall, there is no evidence that baby girls were killed more often.
"It seems as though they weren't using infanticide to manipulate the sex ratio," Mays said.
Read more at Discovery News
Geologists would love to know what controls earthquakes. But one of the best ways to answer that question — drilling into faults — is expensive and difficult. An easier alternative is to study faults exposed on Earth's surface, and look at "fossilized" earthquakes preserved along the faults.
But faults can be several feet wide and filled with crushed-up rock, or they can be inch-thick cracks. How does someone walk up to a crack, point a finger at it and determine an earthquake occurred there?
Sometimes, the tremendous heat created during an earthquake melts rock inside a fault. "That was the gold standard," said Heather Savage, a geophysicist at Lamont-Doherty Earth Observatory in New York. "When you get the melt, it means the fault slipped fast."
(Faults get hot because of friction. Just as rubbing your hands warms them on a winter's day, earthquakes heat the Earth when two sides of a fault slide past each other during a quake.)
But there are plenty of old faults exposed on Earth's surface and very little of this melted rock, called pseudotachylyte, Savage said.
So, over the past few years, Savage and her colleagues have devised a new way to find old earthquakes. It turns out that earthquakes can "cook" dead plants and algae trapped in a fault, similar to how organic material transforms over eons into oil.
And because heat from an earthquake is linked to fault strength, Savage is also testing whether this cooked organic matter reveals clues about fault strength during past earthquakes.
"Temperature rise during an earthquake says something about the strength of the fault when it was slipping, and that is a big unknown in earthquake science," Savage told LiveScience's OurAmazingPlanet. "These kinds of questions are really fundamental if we're ever going to get better at making accurate earthquake predictions."
The technique could prove especially handy at subduction zones — the source of the world's biggest earthquakes — which are often rich in organic material scraped off the ocean floor.
In Alaska, a 60-million-year old subduction zone between the Pacific and North American plates now sits exposed above shoreline at Pasagshak Point on Kodiak Island. This is one of the only places in the world where pseudotachylyte is found on a subduction zone. Savage and her colleagues tested their earthquake "biomarker" method here, comparing the temperature recorded by organic matter to that from the pseudotachylyte at one section of the fault.
In Alaska, the biomarkers were diamondoids, carbon and hydrogen heated until they take on the same basic structure as diamonds. By modeling the heat needed to create diamondoids, Savage and her colleagues estimate the earthquake they found was about a magnitude 7 or magnitude 8, with a temperature rise of between 1,540 and 2,140 degrees Fahrenheit (840 to 1,170 degrees Celsius) and between 3 to 30 feet (1 to 9 meters) of movement. The findings were published Jan. 6 in the journal Geology.
"We're very excited; it's one of the first times we've been able to do this with a new method," Savage said.
Savage noted that this earthquake thermometer only works on faults in sedimentary rocks that carry organic material, and that not all earthquakes will generate a lot of heat. In California, along an ancient strand of the San Andreas Fault called the Punchbowl Fault, the team found a temperature rise of only 1,150 F (625 C), despite geologic evidence of past earthquakes.
The group has several new projects in the works. They're investigating rocks from Japan's JFAST drilling site, at the source of the 2011 Tohoku earthquake, and working on the San Andreas Fault deep drilling project, to see if the slow-moving part of the San Andreas Fault ever had large earthquakes. They are also running laboratory tests to customize those petroleum-industry chemical equations and to better understand the link between temperature on faults and organic matter. And someday, Savage would like to create a "heat map" of a fault.
Read more at Discovery News
The discoveries about the 7,000-year-old Mesolithic ancestral European suggest the young man represents a transition that was still underway to create the lighter-skinned, milk-drinking people of more recent millenniums.
The genome of what's called the La Braña individual appears to have already acquired immunities to diseases that were thought to have been introduced to humans later, at the time when Europeans domesticated animals, which are thought to have transmitted the diseases to humans. The results were a surprise to the researchers who fully expected the man would have lighter skin and a more ancient set of immunity alleles, or groups of genes.
"What we found was just the reverse," said Carles Lalueza-Fox, one of 24 authors on a Jan. 26 paper reporting the discovery in the journal Nature. "So we're not sure what that means."
Other researchers agree that the precocious immunity of the La Braña individual is especially intriguing.
"The most surprising and interesting part is that the authors detected derived alleles in pathogen resistance genes," commented Albert Zink, director of the Institute for Mummies and the Iceman in Bolzano, Italy. "This can shed new light on the evolution and interaction of diseases in human populations. This is of particular interest as we know from other studies that some infectious diseases, such as tuberculosis, most probably have been present long before the Neolithic and doesn't necessarily have a (animal) origin."
The blue eye color was just as unexpected, but less problematic, said Carles Lalueza-Fox.
"We tend to think both things (skin and eye color) are related, but they are different genes," Carles Lalueza-Fox explained.
It's also not clear if there's any evolutionary advantage to blue eyes. It could just be from random genetic drift and not have any purpose. Skin color, on the other hand, is thought to be an adaptation to different amounts and intensity of sunlight.
Just how dark the La Braña man was is impossible to say, Lalueza-Fox told Discovery News, but it's clear he was much darker than modern Spaniards and that his genome is quite unlike that of the modern population level Spanish genome.
The man's lactose intolerance is the one thing that was not surprising, since a hunter-gatherer would not drink milk beyond infancy -- just like other mammals and all modern humans with the exception of those who come from milk-drinking cultures, Carles Lalueza-Fox explained.
Read more at Discovery News
Dark matter — the mysterious stuff that is thought to make up most of the matter in the known universe — may reveal itself during the next decade, one prominent scientist predicts.
When the moment comes, it will result in "a pivotal paradigm shift in physics," Gianfranco Bertone, a physicist with the University of Amsterdam in the Netherlands, said in a talk on dark matter research at a Royal Society Frontiers of Astronomy conference in London in November.
The elusive substance may show itself as researchers set out to test "the existence of some of the most promising dark matter candidates, with a wide array of experiments, including the Large Hadron Collider (LHC) at CERN and a new generation of astroparticle experiments underground and in space," Bertone said.
The universe contains much more matter than scientists can currently detect. Models suggest that this unseen matter makes up about 85 per cent of the universe, but nobody is sure what this missing matter is made of. Telescopes can't observe it, because it gives off absolutely no light.
So far, the only evidence of dark matter's existence comes from the gravitational effects it exerts on visible matter. "We see the effects on all scales with astrophysical and cosmological observations," Bertone said.
But despite promising hints from numerous recent experiments, the hunt for dark matter's true identity goes on.
The key candidates for the stuff so far remain restricted to the realm of theory — weakly interacting massive particles (WIMPs), believed to constitute the bulk of dark matter, and axions, assumed to be much lighter and colder particles. It is thought that there are a lot of axions around, and that they constantly rain down on Earth from space.
A failure to find dark matter in the near future would imply that researchers might be on the wrong track and need to rethink their approach to the problem, Bertone said.
Scientists are more hopeful than ever of success despite the failure of one of the most promising detectors, the Large Underground Xenon experiment (LUX), to spot dark matter particles during its first 90-day run in 2013.
LUX is a liquid xenon experiment set up to detect the extremely rare collisions between WIMPs and regular matter on Earth. It is buried about 1 mile (1.6 kilometers) deep in a mine in the Sanford Underground Research Facility in South Dakota.
In 2014, LUX will probe for dark matter longer than ever before, during an upcoming 300-day run.
Besides hiding detectors underground, there are other ways to search for the mysterious dark matter. For example, there are direct detectors located in space, such as the Alpha Magnetic Spectrometer, which was installed on the International Space Station in 2011. AMS looks for the shower of radiation that dark matter particles are assumed to produce as they collide and annihilate. It is thought that this radiation also includes gamma rays.
Another space-based detector is NASA's Fermi telescope, which launched in 2008. This instrument is scanning the center of the Milky Way galaxy, where dark matter is believed to be concentrated, looking for excess gamma rays.
Many scientists are placing their bets on the Large Hadron Collider. Once it is up and running again in 2015, it will resume smashing particles together, in the hope of creating dark matter in the lab.
The LHC aims to create a type of matter called supersymmetric dark matter. If the LHC finds any particles that could be dark matter, its results would be compared to the data from astroparticle experiments.
"It is quite clear that unless the theoretical description of dark matter is very simple, it will be hard to identify it with a single type of experiment, whereas a combination of them should provide sufficient information," Bertone said.
Although the current experiments are looking for specific particles that scientists believe dark matter may consist of, many researchers remain open to the possibility that dark matter could be made of something completely different.
It's also possible that a whole zoo of particles makes up the invisible matter, Bertone said. "Many studies today address the possibility that dark matter is made not of one but many particle species."
So even if scientists do not find the particles they are currently looking for, it will not automatically mean that dark matter does not exist.
"The only way to prove that dark matter does not exist is to show that all these data have been misinterpreted, for instance because the law of gravity we adopted — Albert Einstein's Theory of General Relativity — is wrong," Bertone said. "Despite much effort, no satisfactory theory of gravity exists today that can be reconciled with all observational data without assuming the existence of some forms of dark matter."
Einstein's general theory of relativity describes how objects warp space and time to create gravity.
But many scientists think that dark matter will end up showing its face, and soon.
"In my view, the single most promising class of dark matter experiments over the next decade are the underground detectors — LUX, XENON-1ton, LX, and others," said Dan Hooper, a physicist at Fermilab in Batavia, Ill.
The detectors "just keep getting more and more sensitive, and already rule out many otherwise attractive dark matter candidates. The LHC and gamma-ray telescopes are also very important players in the hunt for dark matter," he added.
Read more at Discovery News