Mar 28, 2015
One of the dominant theories of our evolution is that our genus, Homo, evolved from small-bodied early humans to become the taller, heavier and longer legged Homo erectus that was able to migrate beyond Africa and colonise Eurasia. While we know that small-bodied Homo erectus -- averaging less than five foot (152cm) and under 50kg -- were living in Georgia in southern Europe by 1.77 million years ago, the timing and geographic origin of the larger body size that we associate with modern humans has, until now, remained unresolved.
But a joint study by researchers at the Universities of Cambridge and Tübingen (Germany), published today in the Journal of Human Evolution, has now shown that the main increase in body size occurred tens of thousands of years after Homo erectus left Africa, and primarily in the Koobi Fora region of Kenya. According to Manuel Will, a co-author of the study from the Department of Early Prehistory and Quaternary Ecology at Tübingen, "the evolution of larger bodies and longer legs can thus no longer be assumed to be the main driving factor behind the earliest excursions of our genus to Eurasia."
Researchers say the results from a new research method, using tiny fragments of fossil to estimate our earliest ancestors' height and body mass, also point to the huge diversity in body size we see in humans today emerging much earlier than previously thought.
"What we're seeing is perhaps the beginning of a unique characteristic of our own species -- the origins of diversity," said Dr Jay Stock, co-author of the study from the University of Cambridge's Department of Archaeology and Anthropology. "It's possible to interpret our findings as showing that there were either multiple species of early human, such as Homo habilis, Homo ergaster and Homo rudolfensis, or one highly diverse species. This fits well with recent cranial evidence for tremendous diversity among early members of the genus Homo."
"If someone asked you 'are modern humans 6 foot tall and 70kg?' you'd say 'well some are, but many people aren't,' and what we're starting to show is that this diversification happened really early in human evolution," said Stock.
The study is the first in 20 years to compare the body size of the humans who shared Earth with mammoths and sabre-toothed cats between 2.5 and 1.5 million years ago. It is also the first time that many fragmentary fossils -- some as small as toes and tiny ankle bones no more than 5cm long -- have been used to make body size estimates.
Comparing measurements of fossils from sites in Kenya, Tanzania, South Africa, and Georgia, the researchers found that there was significant regional variation in the size of early humans during the Pleistocene. Some groups, such as those who lived in South African caves, averaged 4.8 feet tall; some of those found in Kenya's Koobi Fora region would have stood at almost 6 foot, comparable to the average of today´s male population in Britain.
"Basically every textbook on human evolution gives the perspective that one lineage of humans evolved larger bodies before spreading beyond Africa. But the evidence for this story about our origins and the dispersal out of Africa just no longer really fits," said Stock. "The first clues came from the site of Dmanisi in Georgia where fossils of really small-bodied people date to 1.77 million years ago. This has been known for several years, but we now know that consistently larger body size evolved in Eastern Africa after 1.7 million years ago, in the Koobi Fora region of Kenya."
"We tend to simplify our interpretations because the fossil record is patchy and we have to explain it in some way. But revealing the diversity that exists is just as important as those broad, sweeping explanations."
Previous studies have been based on small samples of only 10-15 fossils because techniques for calculating the height and body mass of individuals required specific pieces of bone such as the hip joint or most of a leg bone. Stock and Will have used a sample size three times larger, estimating body size for over 40 specimens contained in collections all over Africa and Georgia, making it the largest comparative study conducted so far.
Instead of waiting for new fossils to be discovered and hoping that they contained these specific bones, Stock and Will decided to try a different approach and make use of previously over-looked fossils. In what Stock describes as a "very challenging project," they spent a year developing new equations that allowed them to calculate the height and body mass of individuals using much smaller bones, some as small as toes. By comparing these bones to measurements taken from over 800 modern hunter-gatherer skeletons from around the world and applying various regression equations, the researchers were able to estimate body size for many new fossils that have never been studied in this way before.
Read more at Science Daily
Over the months and years after landing, the High-Resolution Imaging Science Experiment (HiRISE) camera on board NASA’s Mars Reconnaissance Orbiter has been keeping track of changes around Curiosity’s landing zone (named “Bradbury Landing”), the crash site of the sky crane and the parachute-endowed back-shell that slowed the rover’s entry into the Martian atmosphere.
After disturbing the ruddy regolith on the Martian surface, usually, over time, the darkened area is expected to fade, slowly returning to its natural state. But recent HiRISE imagery of four components of Curiosity’s landing have faded inconsistently, potentially revealing a previously unknown Mars surface dynamic.
“Spacecraft like Curiosity create these dark blast zone patterns where bright dust is blown away by the landing,” said Ingrid Daubar, a HiRISE team scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We expected to see them fade as the wind moved the dust around during the months and years after landing, but we’ve been surprised to see that the rate of change doesn’t appear to be consistent.”
These followup observations are, in part, useful for NASA’s next Mars mission, InSight, that will launch in 2016. The InSight lander will deploy a probe that will be hammered a few meters into the ground to measure the heat traveling through the planet’s crust.
Any darkening of the surface is therefore really important for planetary scientists to understand. The darker the surface, the more sunlight that surface will absorb. The brighter the surface is, the more light is reflected and therefore less heating occurs.
From Discovery News
Mar 27, 2015
The study, published in the latest issue of the Journal of Mammalogy, provides evidence that the iconic black and white bears are not always solitary creatures, as was once thought, but instead have rich and complex social lives.
“Pandas are such an elusive species and it’s very hard to observe them in wild, so we haven’t had a good picture of where they are from one day to the next,” co-author Vanessa Hull of Michigan State University said in a press release.
Hull and her colleagues placed GPS collars on five giant pandas at the Wolong Nature Reserve in China. Caretakers there have named the pandas: Pan Pan, Mei Mei and Zhong Zhong (three adult females), Long Long (a young female), and Chuan Chuan (a male).
The pandas, wearing their new high tech bling, were released back into the reserve.
“This was a great opportunity to get a peek into the panda’s secretive society that has been closed off to us in the past,” co-author Jindong Zhang said.
Hull added, “Once we got all the data in the computer we could see where they go and map it. It was so fascinating to sit down and watch their whole year unfold before you like a little window into their world.”
The researchers determined that two of the adult females, Chuan Chuan and Mei Mei, hung out together for long periods during the fall and outside of the spring mating season. With them was little Long Long, the young female panda.
As for the male Chuan Chuan, he traveled much more than the females did, but frequently came back to check on them. As he did so, he would advertise his presence with scent marking, meaning that he rubbed his smelly glands against nearby trees. The females seemed loyal to him, so the smell was definitely not a turn off.
Could male pandas in the wild keep harems? The researchers are still learning about giant panda sex lives. The Chinese government is protective of its endangered pandas, and for more than a decade banned putting GPS collars on them, so data is still relatively scarce.
From this latest study, the scientists also found that pandas spend a lot of time munching bamboo in up to 30 favorite areas.
“They pretty much sit down and eat their way out of an area, but then need to move on to the next place,” Hull explained.
Read more at Discovery News
The new species, Yawunik kootenayi, lived more than 250 million years before the first dinosaurs. It is described in the latest issue of the journal Paleontology.
“This creature is expanding our perspective on the anatomy and predatory habits of the first arthropods, the group to which spiders and lobsters belong,” lead author Cedric Aria of the University of Toronto said in a press release.
“It has the signature features of an arthropod with its external skeleton, segmented body and jointed appendages, but lacks certain advanced traits present in groups that survived until the present day,” Aria added. “We say that it belongs to the ‘stem’ of arthropods.”
The fossil is the first new species to be described from the Marble Canyon site at the Canadian Burgess Shale located in British Columbia’s Kootenay National Park. The animal’s name therefore takes on “Kootenay.”
As for “Yawunik,” the word refers to a mythological figure that the native Ktunaxa people recognize. This legendary beast was a huge and fierce marine predator, which caused such killing mayhem that it triggered an epic hunt by other animals to bring the threat down.
In terms of the non-fiction Yawunik, close examination of the animal’s remains reveals that the individual had long front appendages that look like the antennae of modern beetles or shrimp. These appendages, however, were composed of three long claws, two of which had opposing rows of teeth.
Yawunik could move these front appendages backward and forward. The researchers believe this predator spread them out during an attack, and then retracted them under its body when swimming.
“Unlike insects or crustaceans, Yawunik did not possess additional appendages in the head that were specifically modified to process food,” said Aria. “Evolution resulted here in a combination of adaptations onto the frontal-most appendage of this creature, maybe because such modifications were easier to acquire.”
Read more at Discovery News
A 2.3-ton tombstone was lowered overnight into place, sealing the king beneath and marking Richard’s place of honor in Leicester cathedral.
Coming from a quarry in North Yorkshire which Richard would have owned as the Duke of York, the Swaledale fossil stone sits on a slab of dark Kilkenny marble, inscribed with the king’s name, dates, motto and coat of arms. The latter is made in a variety of marble and semi-precious stones.
The Swaledale tombstone, which polishes to a fine finish, contains fossil remains of invertebrate marine creatures. The stone was formed at the bottom of a shallow sea that covered much of today’s United Kingdom during the early Carboniferous period, some 350 million years ago. ”The fossils within it are long dead creatures immortalized,” the cathedral said.
Basically the shape and size of a sarcophagus, the tombstone features a deeply incised cross.
“The deep cut in the stone will allow light to flood through it, symbolizing that death is not the end, but that we all receive new life in Christ,” the cathedral said in a statement.
The stone tomb’s creation marks one of the biggest events in the history of Leicester. The design is slightly higher at the head, “as if rising to meet the risen Jesus,” the cathedral said.
The reinterment is considered to be a final act and there are no plans to reopen the tomb in the future.
Read more at Discovery News
|The punk rocker frog can shape-shift its skin to blend in with its surroundings. Here it is in its weekend garb at left, and business casual at right.|
It took three years before Krynak could return to Ecuador and secure a live specimen. This time, they dropped their frog in a cup and took it back to camp. But when they went to remove it, to their crushing dismay, it looked like your average smooth-skinned frog. “And I’m so mad at myself because I’m the one that captured it and put it in the cup,” Krynak recalls. “I was like, how could I have possibly picked up the wrong frog?” Devastated, she dropped some moss in the cup because she “just wanted to make him more comfortable,” and walked away.
Returning a few minutes later, Krynak discovered something incredible: The frog was spiky again. It was apparently changing the texture of its skin to better blend in with its surroundings, and that’s very weird indeed for a vertebrate. Highfalutin invertebrates like the cuttlefish, sure, all the time they’re transforming both the color of their skin and its texture. But not vertebrates. So not only had Krynak found herself a new species, but a new species that changed how scientists think about amphibian camouflage. In a paper published Tuesday, she dubbed the spiky wonder Pristimantis mutabilis, known informally as the punk rocker frog. It’s the [insert your favorite punk star here so I don’t have to pick one and get angry emails about my choice] of the rainforest.
Now, if you’re a relatively helpless creature like a frog, you have a few options for adaptations so you don’t die all the time. Some frogs excrete toxins through their skin, like the famous poison dart frogs, which don’t even bother blending in. In fact, they to present flashy colors to wink-wink-nudge-nudge at predators that they should avoid them. Others try mimicking their surroundings. That seems like what the punk rocker frog is doing, morphing its skin over the course of a few minutes when it finds itself on, say, moss, in order to fool predators (though researchers have more testing in front of them to confirm this).
According to Krynak, how exactly the frogs change their skin texture is unclear. For all they know, it’s a totally different method than the one cephalopods use, but it’s worth mentioning that cuttlefish and octopuses can change the texture of their skin because of tiny structures called papillae distributed all over the creature’s body. These structures are controlled by tiny specialized muscles, some of which are arranged horizontally, and others in concentric circles. The circular muscles push the tissue up, while the horizontal ones give the papillae its shape, which can look a bit like a ping-pong paddle. So it may be the punk rocker frog is using a muscular trick somewhere along these lines.
|Pristmantis sobetes, the other species of skin-morphing frog.|
What could be going on here? “There’s this really cool evolutionary story here,” says Krynak, “these two species are related, but are of two differing groups of frogs, so we have either convergent evolution happening,” that is, the two frogs have developed the shape-shifting ability independently, “or it could be that all of the frogs in the genus at one point had the skin-morphing ability, then for whatever reason lost the trait,” though Krynak finds that unlikely. “Or it could be that many of the other species out there that are closely related actually have this trait, and we just haven’t documented it yet.”
And that’s the really exciting bit. Could there be a whole slew of punk frogs in South America that can pull off this remarkable behavior, going to shows and yelling at each other or whatever it is punks are supposed to do? And they don’t even need to be in the same Pristimantis genus—people just generally know so very little about frogs, in South America or elsewhere. I mean, clearly, even when we catch and describe them the first time around like scientists did with the first species 30 years ago, the shape-shifting is something that’s easily missed. So it’ll be interesting to see what research comes out of those jungles in the coming years.
That is, if we don’t wipe the frogs off the planet first.
Protecting a Punk Rock Superstar
Frogs are in serious trouble worldwide, with half of all species at risk of extinction. Part of the problem is a nasty, hypervirulent fungus known as chytrid. It attacks a frog’s skin—which the frog relies on to absorb moisture and vital salts—often wiping out whole populations.
But according to Robin Moore, a conservation biologist at the Amphibian Survival Alliance, that’s not the biggest threat. Habitat loss is. The fungus already has ripped through Ecuador, and the frogs that have survived so far still have to put up with the country’s many industries. “So in Ecuador you have mining, you have agriculture, you have cow pastures,” says Moore. “And forests continue to be cut down.”
The problem is, frogs tend to have small distributions: Lose a single stream system and a species can vanish forever. Ironically enough, though, this can make conserving frogs easier. “You can protect relatively small tracts of habitat, and essentially save a species,” says Moore.
|The punk rocker frog’s habitat. No wonder the things are hard to find. It’s all, like, foggy and stuff.|
Could the bizarre punk rocker frog do the same for Ecuador? “These kinds of species can be flagship species for the conservation of an area,” says Moore. “I think when people realize they have a unique species, it does instill that sense of pride. So I think for me also that sort of lends weight to a discovery like this.”
Read more at Wired Science
Mar 26, 2015
The study shows that two genes that confer resistance against a particularly strong class of antibiotics can be shared easily among a family of bacteria responsible for a significant portion of hospital-associated infections.
Drug-resistant germs in the same family of bacteria recently infected several patients at two Los Angeles hospitals. The infections have been linked to medical scopes believed to have been contaminated with bacteria that can resist carbapenems, potent antibiotics that are supposed to be used only in gravely ill patients or those infected by resistant bacteria.
"Carbapenems are one of our last resorts for treating bacterial infections, what we use when nothing else works," said senior author Gautam Dantas, PhD, associate professor of pathology and immunology. "Given what we know now, I don't think it's overstating the case to say that for certain types of infections, we may be looking at the start of the post-antibiotic era, a time when most of the antibiotics we rely on to treat bacterial infections are no longer effective."
Dantas and other experts recommend strictly limiting the usage of carbapenems to cases in which no other treatments can help.
The study, conducted by researchers at Washington University, Barnes-Jewish Hospital and the National University of Sciences and Technology in Pakistan, is available online in Emerging Infectious Diseases.
The researchers studied a family of bacteria called Enterobacteriaceae, which includes E. coli, Klebsiella pneumoniae and Enterobacter. Some strains of these bacteria do not cause illness and can help keep the body healthy. But in people with weakened immune systems, infections with carbapenem-resistant versions of these bacteria can be deadly.
The Centers for Disease Control and Prevention named carbapenem-resistant Enterobacteriaceae as one of the three most urgent threats among emerging forms of antibiotic-resistant disease. Studies have shown the fatality rate for these infections is above 50 percent in patients with weakened immune systems.
Two genes are primarily responsible for carbapenem-resistant versions of these disease-causing bacteria. One gene, KPC, was detected in New York in 2001 and quickly spread around most of the world, with the exception of India, Pakistan and other South Asian countries. This gene was present in the bacteria that recently contaminated medical equipment in a Los Angeles hospital where two patients died.
A second carbapenem resistance gene, NDM-1, was identified in 2006 in New Delhi, India. It was soon detected throughout South Asia, and most patients infected by bacteria with NDM-1 have had an epidemiological link to South Asian countries.
Dantas and his collaborators were curious about why the two resistance genes seemed to be geographically exclusive. For the study, they compared the genomes of carbapenem-resistant bacteria isolated in the United States with those of carbapenem-resistant bacteria isolated in Pakistan.
Based on the apparent geographic exclusivity of the two resistance genes, the scientists expected to find that bacteria from the two regions were genetically different. Such differences could explain why the two resistance genes weren't intermingling. But the researchers' results showed otherwise. The bacteria's high genetic similarity suggests that the antibiotic resistance genes could be shared easily between bacteria from the two geographic regions.
The researchers also sequenced a special portion of bacterial genetic material called plasmids. Most of a bacteria's DNA is found in its chromosome, but bacteria also have many extra, smaller and circular bits of DNA known as plasmids that easily can pass from one bacterial strain to another. A plasmid is like a bacterial gene delivery truck; it is the primary way antibiotic resistance genes spread between bacteria.
Read more at Science Daily
The researchers say the technique provides a realistic method to generate large ensembles of entangled atoms, which are key components for realizing more-precise atomic clocks.
"You can make the argument that a single photon cannot possibly change the state of 3,000 atoms, but this one photon does -- it builds up correlations that you didn't have before," says Vladan Vuletic, the Lester Wolfe Professor in MIT's Department of Physics, and the paper's senior author. "We have basically opened up a new class of entangled states we can make, but there are many more new classes to be explored."
Vuletic's co-authors on the paper are Robert McConnell, Hao Zhang, and Jiazhong Hu of MIT, as well as Senka Cuk of the University of Belgrade.
Atomic entanglement and timekeeping
Entanglement is a curious phenomenon: As the theory goes, two or more particles may be correlated in such a way that any change to one will simultaneously change the other, no matter how far apart they may be. For instance, if one atom in an entangled pair were somehow made to spin clockwise, the other atom would instantly be known to spin counterclockwise, even though the two may be physically separated by thousands of miles.
The phenomenon of entanglement, which physicist Albert Einstein once famously dismissed as "spooky action at a distance," is described not by the laws of classical physics, but by quantum mechanics, which explains the interactions of particles at the nanoscale. At such minuscule scales, particles such as atoms are known to behave differently from matter at the macroscale.
Scientists have been searching for ways to entangle not just pairs, but large numbers of atoms; such ensembles could be the basis for powerful quantum computers and more-precise atomic clocks. The latter is a motivation for Vuletic's group.
Today's best atomic clocks are based on the natural oscillations within a cloud of trapped atoms. As the atoms oscillate, they act as a pendulum, keeping steady time. A laser beam within the clock, directed through the cloud of atoms, can detect the atoms' vibrations, which ultimately determine the length of a single second.
"Today's clocks are really amazing," Vuletic says. "They would be less than a minute off if they ran since the Big Bang -- that's the stability of the best clocks that exist today. We're hoping to get even further."
The accuracy of atomic clocks improves as more and more atoms oscillate in a cloud. Conventional atomic clocks' precision is proportional to the square root of the number of atoms: For example, a clock with nine times more atoms would only be three times as accurate. If these same atoms were entangled, a clock's precision could be directly proportional to the number of atoms -- in this case, nine times as accurate. The larger the number of entangled particles, then, the better an atomic clock's timekeeping.
Picking up quantum noise
Scientists have so far been able to entangle large groups of atoms, although most attempts have only generated entanglement between pairs in a group. Only one team has successfully entangled about 100 atoms -- the largest mutual entanglement to date, and only a small fraction of the whole atomic ensemble.
Now Vuletic and his colleagues have successfully created a mutual entanglement among 3,000 atoms, virtually all the atoms in the ensemble, using very weak laser light -- down to pulses containing a single photon. The weaker the light, the better, Vuletic says, as it is less likely to disrupt the cloud. "The system remains in a relatively clean quantum state," he says.
The researchers first cooled a cloud of atoms, then trapped them in a laser trap, and sent a weak laser pulse through the cloud. They then set up a detector to look for a particular photon within the beam. Vuletic reasoned that if a photon has passed through the atom cloud without event, its polarization, or direction of oscillation, would remain the same. If, however, a photon has interacted with the atoms, its polarization rotates just slightly -- a sign that it was affected by quantum "noise" in the ensemble of spinning atoms, with the noise being the difference in the number of atoms spinning clockwise and counterclockwise.
"Every now and then, we observe an outgoing photon whose electric field oscillates in a direction perpendicular to that of the incoming photons," Vuletic says. "When we detect such a photon, we know that must have been caused by the atomic ensemble, and surprisingly enough, that detection generates a very strongly entangled state of the atoms."
Eugene Polzik, a professor of quantum optics at the Niels Bohr Institute in Copenhagen, sees the group's successful mutual entanglement of atoms as "a remarkable achievement."
"The technique significantly broadens the options for generating and operating on non-classical, entangled states of atomic ensembles," says Polzik, who was not involved in the research. "As such, it can be useful for clocks, quantum sensing of magnetic fields, and quantum communication."
Read more at Science Daily
In research published today in PLOS Computation Biology, University of Bristol, U.K., researchers concluded that bats avoid collisions thanks to one simple practice: listen in on a nearby bat and copy the route it has just taken.
To determine their surroundings bats use echolocation, or biosonar -- sending out high-pitched calls and then using the returning echoes to effectively map out what's up ahead.
Marc Holderied, of Bristol's School of Biological Sciences, recorded video of the flight trajectories and interactions of these echolocating fliers -- specifically, pairs of Daubenton's bats (Myotis daubentonii) -- while they foraged for insects over low water.
Holderied and his team then used modeling tools and mathematical functions to measure the calls of interacting pairs of bats and compare the flight headings of one bat vs. the other for select time intervals.
The team found that the bats were observing what they termed "traffic rules" -- slowing down to avoid collisions, swapping follower and leader roles, making tandem turns and chasing each other.
How did they do all of this precision flying without accidents? The scientists found that the bats copied each other's flight headings, taking readings that happened just 500 milliseconds prior -- or only slightly more time than it takes for a human eye to blink.
"The bats seem to have adopted a simple trick: once another individual is close enough for your biosonar to pick up its echo, copy this individual's flight direction within four to five of your own wingbeats," Holderied explained in a news release.
Read more at Discovery News
By observing massive colliding galaxy clusters, astronomers have been able to deduce how dark matter behaves during these vast encounters. Until now, we’ve studied a handful of cluster smashups, only allowing us a snapshot of dark matter interactions.
But a new survey by the NASA/ESA Hubble Space Telescope and NASA’s Chandra X-ray Observatory has focused on 72 galactic cluster collisions from all angles and at different times during their collisions. This has given us the unprecedented opportunity to see how dark matter interacts with itself over time.
And in results to be published on March 27 (Friday) in the journal Science, researchers have pieced together a chronology of sorts; using the series of cluster collisions to see how the interactions between dark matter clouds these clusters are known to contain.
“We know how gas and stars react to these cosmic crashes and where they emerge from the wreckage. Comparing how dark matter behaves can help us to narrow down what it actually is,” said lead author David Harvey of the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland.
Dark matter’s presence is known only by its interactions with normal matter through gravity. It does not, however, interact via the electromagnetic force, which is why we cannot directly see it — it does not emit, scatter or reflect light — it is more “invisible” than “dark.”
In this new research, Harvey and his team realized just how invisible this stuff is, even to itself.
As two galactic clusters collide, the stars, gas and dark matter interact in different ways. The clouds of gas suffer drag, slow down and often stop, whereas the stars zip past one another, unless they collide — which is rare. On studying what happens to dark matter during these collisions, the researchers realized that, like stars, the colliding clouds of dark matter have little effect on one another.
Thought to be spread evenly throughout each cluster, it seems logical to assume that the clouds of dark matter would have a strong interaction — much like the colliding clouds of gas as the colliding dark matter particles should come into very close proximity. But rather than creating drag, the dark matter clouds slide through one another seamlessly.
“A previous study had seen similar behavior in the Bullet Cluster,” said co-investigator Richard Massey of Durham University in the UK. “But it’s difficult to interpret what you’re seeing if you have just one example. Each collision takes hundreds of millions of years, so in a human lifetime we only get to see one freeze-frame from a single camera angle. Now that we have studied so many more collisions, we can start to piece together the full movie and better understand what is going on.”
Read more at Discovery News
Mar 25, 2015
Harvard geneticist George Church used DNA from Arctic permafrost woolly mammoth samples to copy 14 mammoth genes -- emphasizing those related to its chilly lifestyle.
"We prioritized genes associated with cold resistance including hairiness, ear size, subcutaneous fat and, especially, hemoglobin," Church told The Sunday Times.
Then, using a kind of DNA cut/paste system called CRISPR (clustered regularly interspaced short palindromic repeat), Church dropped the genes into Asian elephant skin cells.
The result? A petri dish of elephant cells functioning normally with mammoth DNA in them, marking the first time mammoth genes have been on the job since the creature went extinct some 4,000 years ago, as Sarah Fecht, from Popular Science, noted.
Longer term, Church and his team hope to first create hybrid elephant/mammoth embryos, grown in artificial wombs, and then raise hybrid elephants that could be genetically wired to thrive in colder climes -- hopefully expanding their range to live at a greater remove from humans.
Longer, longer term, if the hybrid elephant can be created and successfully integrated in the wild, then the team might even try to bring back the woolly mammoth itself.
From Discovery News
The tiny "mutable rain frog" (Pristimantis mutabilis) was discovered on the western slopes of Ecuador's Andes Mountains, in a protected cloud forest reserve. The misty, fog-enshrouded Chocó cloud forest is a biodiversity hotspot, and the protected area, called Reserva Las Gralarias, is also home to several rare birds and butterflies. A new glass frog species, the Las Gralarias glass frog, was reported there in 2012.
Scientists from Cleveland's Case Western Reserve University and Cleveland Metroparks found the shape shifter during their annual survey of the reserve's amphibian population. For the past 10 years, Katherine Krynak, a biologist and Case Western graduate student, and Tim Krynak, a naturalist and Metroparks project manager, have walked the reserve trails together at night, listening for frog calls and scanning for rare species.
The Krynaks volunteer their time and also support the reserve with a private nonprofit foundation.
The pair first spotted the frog in 2006 and only snapped a photo, but later realized it could be a newfound species when they enlarged the image. They started calling the frog a "punk rocker" for its spiny-textured skin. "It wasn't until we saw the amazing texture of its skin that we thought, 'wow, this is something different,'" Katherine Krynak told Live Science.
A female mutable rain frog is just 0.8 to 0.9 inches (20 to 23 millimeters) long, and males are even smaller, the new study reports. The rain frogs are a species-rich group that skips the tadpole stage and develops into frogs directly within their eggs.
Lead study author Juan Guayasamín, a professor at the Universidad Tecnológica Indoamérica in Ecuador, first suggested the little frog could be a new species, Krynak said. In 2009, the Krynaks finally saw another punk rocker frog and grabbed it for a detailed photo session, putting it in a small plastic cup overnight.
But when Katherine Krynak opened the cup the next morning, the frog's spines were gone. Thinking she had nabbed the wrong frog, Krynak added moss to the cup to make the frog more comfortable until they could return it to the forest that night. "We were both so disappointed because it had taken years to find another one," she said.
But the Krynaks said they couldn't believe their eyes the next time they checked on the frog. Its spiny skin texture had returned.
"It was remarkable," Katherine Krynak said. "We were both kind of in shock at this point."
The Krynaks think the shape-shifting spines may provide camouflage in the mossy forests, but the idea still needs to be tested. Researchers also don't yet know how the frog morphs its skin from smooth to spiny, and then back again.
However, Guayasamín has confirmed that P. mutabilis is a new and unique species through genetic tests and a description of the frog's body size, shape and color. Study co-author Carl Hutter, of the University of Kansas, also documented the frog's calls, identifying three songs that are different from other species.
During the study, Hutter also discovered a relative of the punk rocker rain frog that can also change its skin texture. This previously known species, called Primates sobetes, has similar markings but is twice as large as the newly found rain frog.
The shape-changing abilities of both frogs are reported today (March 24) in the Zoological Journal of the Linnean Society.
The two shape-shifting frogs are in different groups, which suggests that the trait evolved independently or is present in more species than has been previously recognized, Krynak said.
Read more at Discovery News
Measurements taken by NASA's Cassini spacecraft have shown that the ringed planet might have a longer day than originally calculated from measurements taken by the Voyager 2 probe more than 20 years earlier. In an effort to pin down Saturn's rotation period more accurately, a group of scientists took a mathematical approach to the planet, relying on measurements of its gravitational field.
"While an uncertainty of 15 minutes may appear small compared to the approximately 10.5-hour rotation of Saturn, it is actually important to know [the rotation] accurately," lead scientist Ravit Helled, of Tel Aviv University in Israel, told Space.com via email. "The rotation period has an important effect on understanding Saturn's atmosphere dynamics and internal structure."
The rotation mystery
When Voyager 2 visited Saturn in 1981, the probe measured the planet's rotation period at about 10 hours, 39 minutes. But when Cassini first arrived at the planet in the early 2000s, it determined Saturn spun once on its axis every 10 hours and 47 minutes, and those numbers changed each time Cassini took a look.
Gas giant planets like Saturn lack solid land masses that could help determine how quickly a planet spins, so scientists have to fall back on other approaches. Voyager and Cassini relied on measurements of the planet's radio radiation, but because those measurements shifted with each observation, they proved unreliable.
Radio radiation isn't the only method for studying the rotation of a gas giant. For planets where the magnetic field is tilted in relation to the axis the planet rotates around, measurements of the magnetic field can reveal how quickly the planet spins. However, Saturn's magnetic field lines up with its rotation axis, which prevents scientists from relying on that measure.
A third option involves measuring how long it takes for a cloud in Saturn's atmosphere to travel around the planet. But the rotation of the atmosphere doesn't necessarily line up with the rotation of the planet, making this method challenging.
Helled and her team decided to instead take a more mathematical approach to determining how quickly Saturn spins. The team searched for solutions for the rotation period by using coefficients to represent the interior, then searched for the rotation period that the most solutions calculated.
"We did not want the derived period to be associated with a specific internal structure, so we accounted for many possibilities within their physical range," Helled said. "There are many solutions, but it was found that they tend to give a similar rotation period."
The theoretical estimate returned a rotation of almost 10 hours, 33 minutes. This is "in very good agreement with previous estimates that used different methods," Helled said.
The results were published online today (March 25) in the journal Nature.
Testing the theory
The newly returned calculation relied on studies of the planet's well-defined gravitational field. As Cassini traveled around the planet, it measured the tug of Saturn on the spacecraft, determining the strength or weakness of the gravitational pull. Although the gravitational field changes based on differences in the interior, the team's mathematical approach allowed for many possibilities for the interior, all of which reproduce the data measured for the gravitational field.
"The advantage of our method is that it is not associated with a specific interior model for Saturn, does not rely on the cloud-tracking wind properties that have large variability, and allows for the large range of solutions constrained by the measured physical properties of the planet and their uncertainties," Helled said.
The team also used measurements of the planet's oblateness to determine their solution. Oblateness refers to the fact that spinning bodies are almost never perfect spheres; the faster they whirl, the more they bulge around the equator. Saturn is rather thick around the middle, more than even Jupiter, which could indicate a fast spin. However, Helled pointed out that winds also affect oblateness, so strong winds around the equator could lead to a bigger bulge.
After making its theoretical calculation of Saturn's spin, the team turned to Jupiter, a planet whose rotation is well-defined. Using the same mathematical approach, the researchers recovered a theoretical estimate of Jupiter's rotation that matched measurements already made. The result thus validated their method. Helled calls the results of their work on Jupiter "very encouraging."
Read more at Discovery News
In a paper in this week’s Proceedings of the National Academy of Sciences, researchers report that Curiosity has found oxidized nitrogen-bearing compounds in samples collected from three sites in Gale Crater, the 96-mile-wide basin the rover has been exploring since August 2012.
“The samples contained more nitrogen than could be accounted for from known terrestrial instrument sources, with the bulk of the nitrogen in the form of nitric oxide,” scientists wrote in a summary of their research.
The team theorizes that nitric oxide may have been released from decomposing nitrates as the sample was heated for analysis.
“Terrestrial life requires a fixed form of nitrogen for synthesis of crucial biomolecules, and the discovery of indigenous fixed nitrogen in Martian rocks and sediments has implications for the past habitability potential of Mars,” the researchers noted.
Nitrogen is essential for all known forms of life, since it is used in the building blocks of larger molecules like DNA and RNA, which encode the genetic instructions for life, and proteins, which are used to build structures like hair and nails, and to speed up or regulate chemical reactions, NASA said in a related press release about the research.
“There is no evidence to suggest that the fixed nitrogen molecules found by the team were created by life,” NASA added.
“The surface of Mars is inhospitable for known forms of life. Instead, the team thinks the nitrates are ancient, and likely came from non-biological processes like meteorite impacts and lightning in Mars’ distant past,” NASA said.
Read more at Discovery News
Mar 24, 2015
"If you believe in Jesus you will see your image," Ximena Rosero Arango, one of the many people who have come to the site to photograph the mountain, told the newspaper.
The hillside joins a list of rock formations and other natural features around the world that at least vaguely resemble human faces. But the Colombian hillside has garnered more media connection because of its religious connection. There's also an underground rock formation in the Philippines that some think suggests the face on the Shroud of Turin. In 2010, the Telegraph, a British newspaper, and other publications reported that Jesus' likeness also could be seen in Google Maps overhead photo of a field on farmland near Puspokladany in Hungary.
Although some see these phenomena as miraculous, there's another possible explanation: Our minds are hard-wired by evolution to see them.
Read more at Discovery News
The nation of 5 million inhabitants also gets renewable energy contributions from a mix of solar, geothermal and wind power.
Because Costa Rica needs a steady flow of water to maintain such an impressive feat, the Central American nation has budgeted nearly $1 billion to tap into its many volcanoes, expanding its use of geothermal power.
Geothermal energy generated 10 percent of the nation's power last year.
The country tops an impressive list of nations producing much of their power from renewable sources. Reports Quartz, Sweden, Bulgaria and Estonia have already met their 2020 renewable energy goals.
Denmark creates 40 percent of its energy from wind. And the Dutch territory Bonaire is already producing nearly 100 percent of its energy from renewables and hopes to go over the top using algae as a biofuel.
Costa Rica aims to be entirely carbon neutral by 2021, reports inhabit.com.
From Discovery News
According to a CERN news update today (March 24), the delay was triggered by an “intermittent short circuit” in one of the particle accelerator’s magnet circuits and an investigation is underway. “It is a well understood issue, but one that could take time to resolve since it is in a cold section of the machine and repair may therefore require warming up and re-cooling after repair,” writes CERN.
As discussed by Frédérick Bordry, CERN’s Director for Accelerators, any glitch impacting a cryogenic machine is a time amplifier, “so what would have taken hours in a warm machine could end up taking us weeks,” said Bordry in a statement.
Consisting of a main 27 kilometer (17 mile) circumference ring of supercooled electromagnets, the LHC has to undergo a long period of cooling down before the instrumentation is capable of maintaining the relativistic particles in a tightly-controlled and collimated “beam.” Operating at temperatures as close to absolute zero as possible, the ring of electromagnets take time (and lots of energy) to warm up and then cool back down should repairs be needed.
CERN estimates that the restart delay could be anything from a few days to several weeks, but as part of the LHC’s historic voyage to peel back the mysteries of space, time and quantum mechanics, this is only a minor bump in the road.
“All the signs are good for a great run 2,” said Rolf Heuer, Director General of CERN. “In the grand scheme of things, a few weeks delay in humankind’s quest to understand our universe is little more than the blink of an eye.”
Having already achieved its prime mission to identify the Higgs boson, anticipation for the LHC operating at a higher energy regime is nearing fever pitch. Run 2 will see proton beams being circulated around the LHC at an energy of 6.5 TeV — providing collision energies of 13 TeV, almost double the collision energy of the LHC’s first run. The prospects of discovering exotic physics phenomena is tantalizing.
Read more at Discovery News
The predator, named Metoposaurus algarvensis, lived around 220 million years ago and likely ate mostly fish.
Project leader Steve Brusatte told Discovery News that the early amphibian “was a top predator during the time that dinosaurs were first evolving and beginning their march to dominance.”
“We think this ‘super salamander’ is a type of totally bizarre, otherworldly extinct animal,” added Brusatte, who is a paleontologist at the University of Edinburgh’s School of GeoSciences.
He and his team found the animal’s remains at the site of a former lake in southern Portugal. They believe Metoposaurus stomped around the region, living much like crocodiles do today.
It’s doubtful that many other predators dared to take on the big beast.
“This new amphibian looks like something out of a bad monster movie,” Brusatte said. “It was as long as a small car and had hundreds of sharp teeth in its big flat head, which kind of looks like a toilet seat when the jaws snap shut. It was the type of fierce predator that the very first dinosaurs had to put up with if they strayed too close to the water, long before the glory days of T. rex and Brachiosaurus.”
Metoposaurus appears to have been sensitive to changes in climate, however. The researchers think many died at the Portuguese site when the lake they inhabited dried up. This perhaps foreshadowed what was to come some 20 million years later.
At about 201 million years ago, there was a mass extinction event that wiped out most big amphibians like this. At this time, the supercontinent Pangea, which included all of the world’s present day continents, began to break apart.
The changes are significant for dinosaur fans, as the extinctions paved the way for dinosaurs to become the number one terrestrial predators.
Read more at Discovery News
Mar 23, 2015
Black and colleagues write that the CI eruption approximately coincided with the final decline of Neanderthals as well as with dramatic territorial and cultural advances among anatomically modern humans. Because of this, the roles of climate, hominin competition, and volcanic sulfur cooling and acid deposition have been vigorously debated as causes of Neanderthal extinction.
They point out, however, that the decline of Neanderthals in Europe began well before the CI eruption: "Radiocarbon dating has shown that at the time of the CI eruption, anatomically modern humans had already arrived in Europe, and the range of Neanderthals had steadily diminished. Work at five sites in the Mediterranean indicates that anatomically modern humans were established in these locations by then as well."
"While the precise implications of the CI eruption for cultures and livelihoods are best understood in the context of archaeological data sets," write Black and colleagues, the results of their study quantitatively describe the magnitude and distribution of the volcanic cooling and acid deposition that ancient hominin communities experienced coincident with the final decline of the Neanderthals.
In their climate simulations, Black and colleagues found that the largest temperature decreases after the eruption occurred in Eastern Europe and Asia and sidestepped the areas where the final Neanderthal populations were living (Western Europe). Therefore, the authors conclude that the eruption was probably insufficient to trigger Neanderthal extinction.
Read more at Science Daily
One of the most pivotal moments in evolution occurred when a few pioneering fish left the waterabout 350 million to 400 million years ago. These fish evolved into the first tetrapods (four-legged land animals), which ultimately gave rise to amphibians, reptiles, birds and mammals.
To figure out how ancient animals made this shift to land, scientists typically investigate how the limbs of the first tetrapods evolved over time. However, biomechanistKrijn Michel at the University of Antwerp in Belgium and his colleagues suggest that investigating how early tetrapods learned to eat on land is equally important to understanding this key point in evolution.
In the water, fish generate suction with their mouths to help draw in food with the help of a neck bone known as the hyoid. On land, sucking in air to swallow food proved impractical, so tetrapods instead evolved tongues supported by the hyoid that help guide food down their throats. However, much remains unknown about how tetrapod hyoids and tongues evolved.
To learn more about the evolution of tetrapod feeding, the scientists investigated modern amphibious fish known as mudskippers that dine on land. Mysteriously, these fish emerge onto land with their mouths filled with water.
The researchers experimented with five mudskippers from Nigeria, using high-speed video cameras and X-ray scanners to record the fish feeding on shrimp.
Results showed that the mudskippers fed by first exuding water from their mouths and then quickly sucking it back up once it submerged the food. Essentially, the water acted like a tongue.
Read more at Discovery News
“In our solar system planets are pretty widely spread out and there’s literally nothing inside of Mercury’s orbit,” astronomer Gregory Laughlin, with the University of California Santa Cruz, told Discovery News.
“The fact that the default mode of planet formation ... is leading to configurations that are totally unlike our own solar system is something I found really curious. The main feature of our solar system is that the inner part is just missing,” he said.
Enter the “Grand Tack” theory of our solar system’s formation, which suggests that in its infancy, giant Jupiter spiraled inward, swept by the gravitational wake of its own buildup. Like a cosmic bull in a celestial china shop, Jupiter’s gravity would have flung asteroids and proto-planets every which way, creating a shooting arcade that could have easily destroyed planets in the region, Laughlin said.
The story would have ended there were it not for Saturn, which evolved somewhat later and ended up with enough gravitational muscle to counteract Jupiter’s inward spiral, freeing the giant planet to shift back beyond Mars, or so the Grand Tack theory holds.
That left the inner solar system clear for a second-generation of planets to form, Earth among them.
Laughlin and colleagues were less interested in proving Jupiter’s navigational prowess than looking at what impacts the migration could have had.
“Anytime a theory says 'Well this happened and then this happened,' you need to be naturally suspicious. I think that is completely, absolutely valid and the right standpoint to take,” Laughlin said.
But looking at the consequences of the migration provides a very nice test, he added.
Read more at Discovery News
Embedded in the crust 30 kilometers (19 miles) deep, in rock that is 300-600 million years old, the double impact crater has long gone, buried by geological processes, but its imprint in Earth’s crust remains. It covers a vast impact zone some 400 kilometers (250 miles) wide in the Warburton Basin in Central Australia.
“The two asteroids must each have been over 10 kilometers (6.2 miles) across — it would have been curtains for many life species on the planet at the time,” said Andrew Glikson from the Australian National University’s School of Archaeology and Anthropology.
Compared with the famous Chicxulub crater under the Yucatán Peninsula in Mexico, which is famous for causing the extinction of the dinosaurs some 66 million years ago, this Australian impact zone is a monster. The Chicxulub crater is 180 kilometers (110 miles) in diameter and was caused by a single 10 kilometer-wide asteroid; the Warburton Basin impact zone is over twice that size, caused by two Chicxulub-sized impactors.
The discovery came when a geothermal research project drilled out rock from South Australia and the Northern Territory that had been turned to glass; a tell-tail sign that an ancient impact had delivered a very energetic blow. But only on further investigation did the Glikson’s team realize the extent of the the impact.
Magnetic modeling of the crust throughout the region revealed bulges, rich in iron and magnesium, pushing upward into the Earth’s crust. These bulges originated from the Earth’s mantle — the tick layer of rock that separates the core from the crust — acting as ancient bruises left over by the cataclysmic impacts.
“There are two huge deep domes in the crust, formed by the Earth’s crust rebounding after the huge impacts, and bringing up rock from the mantle below,” Glikson said in a press release. The research was published in the journal Tectonophysics this month.
Although the evidence for a massive impact seems clear, some mysteries remain.
Read more at Discovery News
Mar 22, 2015
Silicon dioxide, commonly called silica, is one of the most-abundant natural compounds and a major component of the Earth's crust and mantle. It is well-known even to non-scientists in its quartz crystalline form, which is a major component of sand in many places. It is used in the manufacture of microchips, cement, glass, and even some toothpaste.
Silica's various high-pressure forms make it an often-used study subject for scientists interested in the transition between different chemical phases under extreme conditions, such as those mimicking the deep Earth.
The first-discovered high-pressure, high-temperature denser form, or phase, of silica is called coesite, which, like quartz, consists of building blocks of silicon atoms surrounded by four oxygen atoms. Under greater pressures and temperatures, it transforms into an even denser form called stishovite, with silicon atoms surrounded by six oxygen atoms. The transition between these phases was crucial for learning about the pressure gradient of the deep Earth and the four-to-six configuration shift has been of great interest to geoscientists. Experiments have revealed even higher-pressure phases of silica beyond these two, sometimes called post-stishovite.
A chemical phase is a distinctive and uniform configuration of the molecules that make up a substance. Changes in external conditions, such as temperature and pressure, can induce a transition from one phase to another, not unlike water freezing into ice or boiling into steam.
The team, including Carnegie's Qingyang Hu, Jinfu Shu, Yue Meng, Wenge Yang, and Ho-Kwang, "Dave" Mao, demonstrated that under a range from 257,000 to 523,000 times normal atmospheric pressure (26 to 53 gigapascals), a single crystal of coesite transforms into four new, co-existing crystalline phases before finally recombining into a single phase that is denser than stishovite, sometimes called post-stishovite, which is the team's fifth newly discovered phase. This transition takes place at room temperature, rather than the extreme temperatures found deep in the earth.
Scientists previously thought that this intermediate was amorphous, meaning that it lacked the long-range order of a crystalline structure. This new study uses superior x-ray analytical probes to show otherwise--they are four, distinct, well-crystalized phases of silica without amorphization. Advanced theoretical calculations performed by the team provided detailed explanations of the transition paths from coesite to the four crystalline phases to post-stishovite.
Read more at Science Daily
This is the first time the 5-foot, 10-inch coffin, made of English oak from a Duchy of Cornwall plantation, has been seen.
Richard’s skeleton rests inside an inner lead casket, his bones packed with unbleached linen and laid out as if articulated. The linen cloths are embroidered with boars, roses and consecration crosses so that the remains are covered “in a dignified and honorable way,” the Richard III Society said in a statement.
“White boars are for the ‘blancs sanglier,’ the badge of Richard III; white roses for his House of York; and the crosses because he was an anointed Christian king,“ it added.
In front of a hushed crowd, the university bade farewell to the king with a short ceremony. All of those involved with the excavation were invited to lay a white rose on top of the coffin.
It was here, beneath a council car park, that in 2012 a twisted skeleton was unearthed. Mitochondrial DNA showed a match between Richard III and two of his living relatives, confirming that the bones were indeed those of the last Plantagenet king.
Read more at Discovery News