Apr 18, 2014

Ancient Puppy Paw Prints Found on Roman Tiles

The paw prints and hoof prints of a few meddlesome animals have been preserved for posterity on ancient Roman tiles recently discovered by archaeologists in England.

"They are beautiful finds, as they represent a snapshot, a single moment in history," said Nick Daffern, a senior project manager with Wardell Armstrong Archaeology. "It is lovely to imagine some irate person chasing a dog or some other animal away from their freshly made tiles."

The artifacts, which could be nearly 2,000 years old, were found in the Blackfriars area of Leicester, the English city where the long-lost bones of King Richard III were discovered under a parking lot in 2012. Wardell Armstrong Archaeology was brought in to dig at a site where a construction company plans to build student housing.

At least one of the tiles is tainted with dog paw prints, and one is marked with the hoof prints of a sheep or a goat that trampled on the clay before it was dry.

"My initial thought was that it must have been very difficult being a Roman tile manufacturer with these animal incursions going on all the time," Philip Briggs, another Wardell Armstrong archaeologist, told Live Science in an email.

The tiles were found in layers of rubble that had been laid down as a hard base for subsequent floors, but the artifacts' original context is unclear, Daffern said.

"We don't know if the tiles were originally part of an earlier building or were bought in from elsewhere specifically to raise and stabilize ground," Daffern told Live Science in an email.

Leicester was the stronghold of an Iron Age group known as the Corieltauvi tribe, and it remained an important city after the Roman conquest of Britain in the first century A.D., as it was located along the Fosse Way, a Roman road that connected southwestern England with the East Midlands.

The excavators say that, in addition to the animal-printed tiles, they've uncovered Roman tweezers, brooches, coins and painted wall plaster. They've also unearthed traces of a large Roman building — perhaps a basilica, with a peristyle, or columned porch — that was largely robbed of its masonry during the medieval era for other construction projects.

The archaeologists even discovered late Iron Age artifacts, such as several fragments of clay molds that the Corieltauvi tribe likely used to make coins before the Roman rule. Daffern said it's rare to find sites with coin molds, given how closely managed coin production would have been during the Iron Age.

Read more at Discovery News

$1.5 Mln World Record Gold Crystal Verified

An intricately folded gold nugget turned out to be the largest individual crystal of gold ever found. Earlier this month, scientists at Los Alamos National Laboratory verified that the 7.68-ounce (217.78-gram) lump -- about the weight of a large onion -- is a single, intact gold crystal. With that crystalline pedigree, the value of the nugget rocketed in value from $10,000 to $1.5 million.

Gold normally forms smaller cubic, 8-sided or 12-sided crystals, according to Mineralogy Database. But larger, irregular structures also can form.

Nuggets of gold generally consist of a collection of these crystals pressed together. Geologists and miners rarely find a nugget made up of only one crystal. Decades, ago miners excavated the recently confirmed champion gold crystal in Venezuela. However, controversy surrounded the nugget. In 2006 the nugget was rejected by an auction because of questions over authenticity.

To prove the crystal's integrity, scientists at Los Alamos National Laboratory's Lujan Neutron Scattering Center used two devices. One used sub-atomic particles, called neutrons, to peer inside the nugget and determine its atomic arrangement. The other instrument measured the crystal structure of the gold piece.

However, at only 217 grams, the gold crystal doesn't come close to topping the largest nugget ever found. In 1890, miners uncovered a 173- pound (78-kilogram) nugget in Australia, according to the University of California, Santa Barbara's ScienceLine. The Banco Central Museum in Brazil displays possibly the largest nugget still in existence. That gold behemoth weighs 60.82 kg and contains 52.33 kg of gold.

From Discovery News

Mountainous Fib: Andes Lie About Their Age

The Andes are the world's second greatest mountain region and new research suggests that at least one portion of that region has been lying about its age.

For years, the evidence has been piling up that the Central Andes surged into being about 10 million years ago -- a very short time ago geologically speaking. Now new evidence from volcanic materials on the Puna Plateau suggests that the area was already 4 kilometers high as far back as 36 million years ago. If so, it sets the area apart from the Altiplano, to the north, which is lower and younger, and adds yet another twist to the puzzling processes that created the range.

Team of researchers ventured to the very remote Puna Plateau in Argentina and collected volcanic ash samples that they could study in the lab to determine not only how long ago the ash was erupted from volcanoes, but how far above sea level.

The age was determined by studying the ratios of uranium and lead in tiny zircons crystals. These two elements serve as an internal radiometric timekeepers for volcanic rocks, since uranium decays into lead at well-known rates over millions of years.

Next, the researchers looked for the elevation clues in bits of volcanic glass, or obsidian, that formed in the ash.

“The little glass shards cool and take on water from the environment,” explained Robin Canavan, a PhD candidate at Yale University and the lead author on a paper about the work in the March 31 issue of the journal Geology.

It's the water that reveals the elevation, because as moist air moves up mountains and the water rains (or snows) out, the air tends to lose the heavier kinds of water first -- those made from heavy hydrogen and heavy oxygen isotopes. The effect can be seen today in surface waters in mountains around the world: lighter isotopes of hydrogen and oxygen in H2O are more enriched at higher elevations. Those same isotopes of oxygen and hydrogen can be found captured in volcanic glass.

By putting the radiometic dating together with the paleo-elevation information from the volcanic glass, the team could determine what height the Puna Plateau was when the volcanic ash was deposited on the ground.

“Our work suggests that the region south of the Central Andean plateau, the southern half the Puna, has had a surface elevation very close to modern 4 kilometers (13,000 feet) for 36 million years,” Canavan said. “This pushes it pretty far back from what previous work suggested.”

The discovery is especially appreciated by geologists studying the nearby Altiplano, which appears to have a very different history.

“The Puna and other Altiplano look similar, but they have different mechanisms,” said Carmala Garzione, professor and chair of the Department of Earth and Environmental Sciences at the University of Rochester. “There are fundamentally different processes that are leading to the uplift.”

Both are part of the uplift caused by the subduction of ocean crust under the South American continent. But there are other things going on to thicken the crust and cause the mountains to buoy especially high in the Andes compared to other subduction zones.

Read more at Discovery News

World’s Most Badass Ant Skydives, Uses Own Head as a Shield

When threatened, Cephalotes ants will leap from a branch and glide themselves right back to the trunk. This little guy was … encouraged to demonstrate.
“Where were you born, in a barn?” my dad used to ask when I left doors wide open. Forget about that being a silly question, on account of him being there when I was born in a hospital. Really, we could have avoided all that heartache in the first place if only we were a family of Cephalotes ants, whose soldiers, no joke, use their heads as doors to seal their colonies from intruders.

With a range stretching from Argentina all the way up into the southern U.S., this incredible genus of ants has also mastered the art of rainforest skydiving, leaping from the canopy to avoid predators, only to steer themselves mid-flight right back onto the trunk of their home tree. And they do it with remarkable agility.

But first: that strange head. The various species of Cephalotes have a range of head shapes. Some are almost perfectly circular, like a manhole cover. These ants typically establish their colonies in dead branches of living trees, where wood-boring beetles have conveniently left cavities. “The size of the soldier head is perfectly matched to the size of the beetles that came out of the tree,” said tropical ecologist Stephen Yanoviak of the University of Louisville.  The Cephalotes move in, and at any given time a soldier’s head serves as a door to keep the ants’ many enemies at bay.

In other species, the soldiers have to team up. Cephalotes atratus, below, occupy the hollow branches of living trees, where a longer slit in the wood acts as an entrance to their colony. “What they’ll do is the soldiers and the workers will line up basically cheek to cheek with that fairly flattened head,” said Yanoviak. “And they can collectively block the entrance that way.”

Ants of the Cephalotes genus have enlarged noggins that they use as doors to block the entrances to their colonies. Here, Cephalotes atratus ants close the door right in their comrade’s face. Hope you’ve got a sleeping bag, pal.
But there’s no such thing as a perfect defense. And individual ants can find themselves isolated and defenseless outside the colony. For that, the Cephalotes have developed a leap of faith.

You Are the Wind Beneath My Sclerotized Exoskeleton

Plenty of rainforest critters engage in what’s known as directed aerial descent, essentially a controlled fall. Some snakes do it. Frogs and lizards too. But the Cephalotes and a handful of other ant genera are the first arthropods known to glide to escape predation or, say, an ungainly monkey rambling through.

Studying this sublime behavior is Yanoviak, who, I’m willing to bet, is one of the few people on Earth who has sat in a tree, painted ants white, and flung them off — and gotten paid for it. But through this work he’s found that a staggering 95 percent of the Cephalotes ants he drops will glide over to the trunk and find their way right back up to the nest.

Here’s how they do it. Once airborne, the ants splay their legs out and look for the trunk of the tree. “We did some experiments to show they’re actually targeting the light-colored tree trunks,” said Yanoviak. “We think of tree trunks as brown and kind of dark, but actually in the tropical rainforest they’re bright white because they’re covered with a special species of lichen that makes them reflect very brightly relative to the background.”

By simply moving their legs, the ants can increase or decrease drag in order to change direction, just like a skydiver … with more legs. And if they don’t like their heading, they can correct themselves incredibly quickly. “I’ve seen ants start gliding towards a bright patch of sunlight on a leaf,” said Yanoviak. “And they’ll get maybe half a meter from it and in a split second they’ll change direction and head over towards a tree trunk.”

Cephalotes atratus come equipped with spines. When picked up by humans, they’ll roll their heads back to drive the spikes into skin. This causes an itchy, painful sensation, which may be due to alarm pheromones secreted by the ant. But we won’t know for sure until someone locks a Ph.D. student in a room with a whole lot of Cephalotes atratus ants.
Coming in for a hard landing on vertical surface, though, is damn tricky. Yanoviak has seen ants slam into the tree trunk and bounce off, only to glide right back for a second go. And they’ll keep bounding down the tree until they finally get a solid grip.

From here, the ants will return to the colony surprisingly fast, finding their way with pheromones and a good visual memory of their surroundings. (Yanoviak once dropped a painted ant out of a tree, and just 10 minutes later saw it walking up a nearby branch.)

But why evolve such piloting skills? It’s not like a fall to the leaf litter below would kill them. They’re too light to suffer serious injury on impact — force, after all, equals mass times acceleration. But it isn’t the impact the ants need to worry about.

At least 10 percent of the Amazon is flooded for three to four months of the year, according to Yanoviak. This, of course, brings hungry fish (and, frustratingly, a hit to the ants’ property values). Yanoviak found in his experiments with Cephalotes atratus that 42 percent of the ants that hit water either drowned or were eaten. And even when hitting the unflooded leaf litter, the ants, far out of their element, must contend with all manner of other predators.

So they glide to avoid the dangers below. Life ain’t exactly carefree in the canopy, of course, but Cephalotes are certainly better equipped to handle foes up there. Except for the ones they never see coming.

Attack of the Butt-Reddening Parasite

In 2005, Yanoviak headed to Panama with the BBC to film these wonderful flying ants. A colleague had actually gone to the rainforest two weeks prior to look for the critters, lest they be left with no stars for the show. Some of the specimens he found, though, had bright-red bums. He reported as much to Yanoviak, who told him that he must have the wrong species.

When Yanoviak arrived, he took the specimens into the lab and broke one of the red ants open. Out spilled a mass of worm eggs. “We discovered a new type of nematode parasite that infects these ants,” he recalls, “and causes only the rear end of the ant to turn bright red.”

To his friends, this ant looks ridiculous. To a bird, it looks delicious. And you know what they say. You can pick your friends, but you can’t pick the predator that’s about to consume you.
Under the influence of the parasite, the ant also becomes markedly sluggish and prone to pop its red booty in the air. Why? Well, Yanoviak has never witnessed it, but he hypothesizes that the nematode is steering its host toward doom.

The redness, he reckons, makes the ant look like a berry, and the behavioral manipulation makes it more conspicuous to passing birds. The exoskeleton also weakens, making the red abdomen easily detachable, perfect for such predators to pluck off and swallow. The bird will then expel the eggs in its droppings, which just so happen to be a favorite food of the Cephalotes ants. While the nematode doesn’t necessarily need the bird’s body to complete its life cycle, this is a brilliantly efficient way to quickly spread yourself around the forest — if you don’t mind a tour of a digestive system first.

Read more at Wired Science

Apr 17, 2014

The Fix Was in for Ancient Wrestling Match

Who says only modern-day pro wrestling is fake?

Researchers have deciphered a Greek document that shows an ancient wrestling match was fixed. The document, which has a date on it that corresponds to the year A.D. 267, is a contract between two teenagers who had reached the final bout of a prestigious series of games in Egypt.

This is the first time that a written contract between two athletes to fix a match has been found from the ancient world.

In the contract, the father of a wrestler named Nicantinous agrees to pay a bribe to the guarantors (likely the trainers) of another wrestler named Demetrius. Both wrestlers were set to compete in the final wrestling match of the 138th Great Antinoeia, an important series of regional games held along with a religious festival in Antinopolis, in Egypt. They were in the boys' division, which was generally reserved for teenagers.

The contract stipulates that Demetrius "when competing in the competition for the boy , to fall three times and yield," and in return would receive "three thousand eight hundred drachmas of silver of old coinage …"

There were no pins in this Greek style of wrestling, and the goal of the wrestlers was to throw the other to the ground three times. A wide array of holds and throws were used, a few of which look a bit like a body slam.

The contract includes a clause that Demetrius is still to be paid if the judges realize the match is fixed and refuse to reward Nicantinous the win. If "the crown is reserved as sacred, (we) are not to institute proceedings against him about these things," the contract reads. It also says that if Demetrius reneges on the deal, and wins the match anyway, then "you are of necessity to pay as penalty to my son on account of wrongdoing three talents of silver of old coinage without any delay or inventive argument."

The translator of the text, Dominic Rathbone, a professor at King's College London, noted that 3,800 drachma was a relatively small amount of money — about enough to buy a donkey, according to another papyrus. Moreover, the large sum Demetrius would forfeit if he were to back out of the deal suggests his trainers would have been paid additional money Rathbone said.

The match fixing took place at an event honoring Antinous, the deceased male lover of the Emperor Hadrian (reign A.D. 117-138). After Antinous drowned in the Nile River nearby, the town of Antinopolis was founded in his honor, and he became a god, and statues of him were found throughout the Roman Empire.

The games had been going on for more than a century by the time this contract was created, and brought benefits for the people of Antinopolis. For instance, "You get the visitors; you get the crowd; you get the trade; you get the prestige," Rathbone told Live Science.

The contract was found at Oxyrhynchus, in Egypt, more than a century ago by an expedition led by archaeologists Bernard Grenfell and Arthur Hunt. It was translated for the first time by Rathbone and published in the most recent volume of The Oxyrhynchus Papyri, an ongoing series that publishes papyri from this site. The transcription of the text was done by John Rea, a now-retired lecturer at the University of Oxford and Rathbone did the translation.

The Egypt Exploration Society owns more than 500,000 papyrus fragments from this site, and they are now kept at the Sackler Library at Oxford.

In the modern world, scandals involving bribes to athletes, or athletic officials, often revolve around gambling or attempts to reward a medal to athletes from a particular country.

The winners of ancient games would sometimes be paid sizable amounts of money, or receive lifetime pensions from their hometown, Rathbone said. However, he noted, there was no prize at all for coming in second.

"In ancient competitions, coming first is the one and only thing — no silver, no bronze," Rathbone said. Additionally, the cost of training athletes was considerable. Athletes from wealthy families could pay their own way, but athletes from less-well-off backgrounds could find themselves in debt to their trainers.

"The trainer is going to pay for your food, your accommodations and so on for your training, so you end up in debt to him," Rathbone said.

In this winner-takes-all situation, both sides may have decided to curb their risks by making a deal to fix the match, Rathbone said.

"If you were confident you would win, normally you would go for it," he said. "If you're not sure you would win, maybe you're cutting your risk by saying, 'At least I get the bribe,'" Rathbone said.

But researchers still wonder, why did the guarantors for the athletes create a written contract recording the agreement? "That's the really bizarre thing; isn't it?" Rathbone said, noting that if either side reneged on the deal, it would be hard to take the matter to court.

He has also noted oddities in the way the contract was drawn up. "It doesn't look as though they've actually gone as far as getting a scribe with legal knowledge to do this for them, which makes you wonder if it's a bit of an empty thing," Rathbone said. "It's not really likely that either side is going to [seek recourse] if the other defaults."

Read more at Discovery News

Earth-Likenesses: Have We Discovered Earth 2.0?

Astronomers have announced the groundbreaking discovery of an Earth-sized exoplanet, called Kepler-186f, orbiting a star within its habitable zone. Although this is an exciting finding — and a historic one at that — calling this world “Earth-like” is a little premature.

In fact, Kepler-186f could be completely alien.

In 2011, Discovery News ran a series of articles predicting what scientific breakthroughs were most likely to occur in 2012. In my article “Big Question for 2012: Will We Find Earth 2.0?,” I speculated that, some time in 2012, NASA’s Kepler space telescope would have had enough time to have detected its first bona fide Earth-sized exoplanet orbiting a sun-like star within the habitable zone — the region surrounding a star where water, on a rocky planetary surface, could exist in a liquid state. This idea hints that if there’s liquid water, life (as we know it) may be possible and the search for life elsewhere in the universe is the crux of our fascination with alien worlds orbiting distant stars.

Alas, although Kepler did indeed have enough time to gather orbital data for many small worlds with Earth-like dimensions around their host stars, that announcement didn’t come in 2012 (or in 2013) — although there were many near-misses.

Today, a little over two years later, exoplanetary science has caught up with the world’s expectations and finally produced a world that, from 500 light-years distant, appears to be a ripe “Earth 2.0″ candidate.

“Previously, the exoplanet most like Earth was Kepler-62f, but Kepler-186f is significantly smaller,” David Charbonneau, with the Harvard-Smithsonian Center for Astrophysics, told Discovery News’ Irene Klotz. “Now we can point to a star and say, ‘There lies an Earth-like planet.’”

Why is Kepler-186f so Special?

During its primary mission, Kepler had a fixed stare on one tiny portion of the sky in the direction of the constellation Cygnus, carefully watching the brightness of 150,000 sun-like stars. Should an exoplanet drift in front of one of those stars, Kepler’s sensitive optics registered it as a very slight dip in brightness, an event known as a “transit.” As these exoplanetary candidates continued to orbit their host stars, Kepler registered more and more transits, leaving astronomers in little doubt that the signal is indeed an orbiting exoplanet and not some other transient dark feature like a “starspot.”

With followup observations by ground-based telescopes, these exoplanetary candidates could then be confirmed and added to the growing tally of confirmed small worlds orbiting other stars. There is little doubt that we are in a “Golden Age” of exoplanetary studies.

To find another planet with all the orbital and physical qualities of Earth, however, is a tall order. The sheer technological precision needed to make these detections is mindboggling, but as Kepler is proving, it is absolutely possible to detect worlds smaller than Earth in orbit around stars hundreds of light-years away.

And Kepler-186f has all the attributes that makes us believe that it is a world not so dissimilar to Earth: it orbits a sun-like star (well, the star Kepler-186 is a little smaller and redder than the sun), is approximately the same physical size as our planet (just 10 percent bigger) and has an orbit of 130-days, putting it right on the outside edge of its star’s habitable zone. But it takes more than a planet’s orbit and size to make it truly “Earth-like.”

Exo-Artistic License

As you may have noticed by the vivid artistic renderings of Kepler-186f accompanying today’s announcement, the perceived life-giving potential of Kepler-186f is obvious. The view is from the planet’s surface, looking up at its host star with other planets in the multi-planetary system in tow. On the planet’s surface is an ocean lined with tree-like vegetation. There’s another rendering (pictured top) of a blue world with a thick atmosphere and white fluffy clouds.

The message is clear: ‘This is just like Earth; it’s a planet in another part of the galaxy capable of supporting life as we know it.’

But just as our solar system is a great example of possessing a life-giving world orbiting inside its habitable zone (Earth), there’s two other examples of biologically ‘dead’ planets that orbit inside the sun’s habitable zone: Venus and Mars.

Although we are currently on a quest to work out whether Mars has ever had the potential to support basic forms of life, it’s pretty clear from studies of the Red Planet’s thin atmosphere and radiation-drenched surface that it is not particularly cozy for life. As for Venus (which, coincidentally, is almost the same physical size as Earth), it has an acidic atmosphere that is undergoing a crazy greenhouse effect that literally destroys water molecules. Neither of these “habitable zone” examples are, well, particularly habitable for life as we know it.

So how do we know that Kepler-186f has white fluffy clouds and pine tree-lined coastlines? Hint: We don’t.

We currently have no means to study this fascinating world’s atmosphere, let alone understand whether it has life-giving potential.

“Being in the habitable zone does not mean we know this planet is habitable,” cautions Thomas Barclay, research scientist at the Bay Area Environmental Research Institute at NASA Ames, in a NASA news release. “The temperature on the planet is strongly dependent on what kind of atmosphere the planet has.

“Kepler-186f can be thought of as an Earth-cousin rather than an Earth-twin. It has many properties that resemble Earth.”

Read more at Discovery News

Most 'Earth-Like' Alien World Discovered

About 500 light-years away in the constellation Cygnus lives a star, which, though smaller and redder than the sun, has a planet that may look awfully familiar.

With a diameter just 10 percent bigger than Earth’s, the newly found world is the first of its size found basking in the benign temperature region around a parent star where water, if it exists, could pool in liquid form.

Scientists on the hunt for Earth's twin are focused on worlds that could support liquid surface water, which may be necessary to brew the chemistry of life.

Statistically speaking, Earth-sized planets orbiting in stars’ so-called habitable zones -- not too far away for water to freeze, not too close for it to vaporize -- should be common, recent studies show.

But observations are difficult to come by. NASA’s Kepler space telescope spent four years staring at about 150,000 target stars looking for slight and repeated dips in their light caused by orbiting planets passing by, or transiting, relative to the telescope’s line of sight.

A planet the size of Earth positioned about as far from a host, sun-like star and as far away as Earth orbits the sun would block just 80- to 100 photons of starlight out of every million -- and do so only once every 365 days, notes astronomer Thomas Barclay, with the Kepler science team at NASA’s Ames Research Center in Moffett Field, Calif.

An Earth-sized planet circling a smaller star is an easier target. The newly found world, designated Kepler-186f, obscures about 400 photons of starlight out of every million as it transits its parent star -- and repeats the cycle every 130 days.

“I wouldn’t say this is the ‘bingo’ planet, but this is really one of the major milestones on the road,” Barclay told Discovery News. “This isn’t an Earth twin, but perhaps it’s an Earth cousin.”

Scientists need at least three transits -- plus follow-up observations by ground-based telescopes -- before an extrasolar planet is confirmed. Since the first planet beyond the solar system was discovered in 1996, astronomers have added nearly 1,800 to the list.

"Kepler-186f is significant because it is the first exoplanet that is the same temperature and the same size (well, ALMOST!) as the Earth,” David Charbonneau, with the Harvard-Smithsonian Center for Astrophysics, wrote in an email to Discovery News.

"Previously, the exoplanet most like Earth was Kepler-62f, but Kepler-186f is significantly smaller,” Charbonneau added.

“Now we can point to a star and say, ‘There lies an Earth-like planet,’” he said.

Read more at Discovery News

Centipede Eats Snake from Inside Out

A group of researchers stumbled upon a grisly scene during a field study in Macedonia last year: a dead nose-horned viper with a centipede's head sticking out of its ruptured abdomen.

After a post-mortem, the scientists think it's possible that the centipede quite literally eviscerated the snake from the inside out.

The remnants of the death match were discovered on May 14, 2013, on Golem Grad, an island in Lake Prespa, and described last month in a brief report published in the journal Ecologica Montenegrina.

The unfortunate nose-horned viper (Vipera ammodytes) was a young female that stretched about 2 inches longer than the centipede (7.9 vs. 6 inches, or 20.3 vs. 15.4 centimeters). But the centipede (Scolopendra cingulate) was actually heavier than the snake, tipping the scales at 114 percent of the snake's body weight (4.8 vs. 4.2 grams, or 0.17 vs. 0.14 ounces).

Nose-horned vipers regularly take on small mammals, lizards and birds, and they've been known to eat centipedes successfully, too. But in this particular case, the snake "gravely underestimated" the size and strength of its prey, the scientist wrote.

A dissection revealed that the snake's visceral organs were missing, or in other words, "the entire volume of its body was occupied by the centipede," the scientists wrote. For this reason, the researchers think it's possible the snake's dinner tried to claw its way out, destroying the viper's internal organs along the way, before eventually dying.

Read more at Discovery News

Tiny Carnivore Evolved Into Huge Vegetarians

The earliest ancestor of land-dwelling plant eaters has been found, a new study reports, and there's a surprising fact about the beastie: it was a meat lover.

If you often bite into a juicy steak, burger or other meat, you might wonder why such an animal would have transitioned to become an herbivore in the first place. The answer is that there was a lot of plant-based food for the taking.

"The evolution of herbivory was revolutionary to life on land because it meant terrestrial vertebrates could directly access the vast resources provided by terrestrial plants," paleontologist Robert Reisz, a professor in the Department of Biology at the University of Toronto Mississauga, said in a press release. "These herbivores, in turn, became a major food resource for large land predators."

The newly discovered ancestor of the first terrestrial carnivores has been named Eocasea martinis. Its skeleton, which was just about 6.5 inches long, belonged to a juvenile that lived in what is now Kansas 300 million years ago. That's nearly 80 million years before the age of dinosaurs.

The researchers think the prehistoric animal feasted on insects and other small animals.

For the study, published in PLOS ONE, Reisz and colleague Jörg Fröbisch of the Museum für Naturkunde and Humboldt-University in Berlin compared Eocasea to skeletons for known related animals. They determined that Eocasea belonged to a certain branch (caseid) of the group Synapsid. This group, which consisted of both carnivores and herbivores, ultimately evolved into modern living mammals.

"Eocasea is one of the oldest relatives of modern mammals and closes a gap of about 20 million years to the next youngest members of the caseid family," Fröbisch said. "This shows that caseid synapsids were much more ancient than previously documented in the fossil record."

It's also the most primitive member of that group, with later members being plant lovers. This shows that large, land-living herbivores evolved from small carnivores. (I also love the extremes of that group. While Eocasea was small- sort of a munchkin pre-mammal from Kansas- later herbivorous members of the group could weigh over 1100 pounds.)

"Eocasea is the first animal to start the process that has resulted in a terrestrial ecosystem with many plant eaters supporting fewer and fewer top predators," Reisz said.

It's not that easy to digest and process high-fiber plant material, so evolving into a plant eater isn't something that can happen over night. The ability arose independently at least five times in the history of our planet, including twice in reptiles.

Read more at Discovery News

Apr 16, 2014

Frogs Shrinking and Squeaking as Climate Warms

The tweets of Puerto Rico’s unofficial mascot, the common coqui frog, became higher pitched during the past two decades, while the animals grew shorter. At the same time, the island increased in average temperature.

“We think the animal adapted to temperature change by becoming smaller, which we believe causes the differences in their calls,” said Sebastiaan Meenderink, a UCLA physicist and co-author of a recent study documenting the declining dimensions of the coqui frog, in a press release.

Male coqui frogs (Eleutherodactylus coqui) now average 10 percent shorter than they did 23 years ago. Similarly to how a Chihuauhua dog has a higher pitched bark than a great Dane, the coqui’s mating calls now register at a higher pitch because of their smaller bodies.

The soprano-singing coqui males could have trouble attracting females or defending their territory from other males. Male coqui frogs duel using their shrill “coh..kuii” calls, which gave the frog its name. Rival males chirp back and forth. The first frog to lose the beat also loses this amphibian rap battle.

“If current trends continue unabated, the coqui frog will sound and look quite different before this century is over,” said co-author Peter Narins, a UCLA biologist who has been studying coqui for four decades.

Read more at Discovery News

Siberian Mummies in Copper Masks Pose Mystery

Russian archaeologists have resumed excavations in a remote site near the Arctic Circle in the attempt to understand a perplexing find of medieval mummies clad in copper masks.

Roughly 1,000 years old, the mummies were found during a series of excavations that started in 1997 in a Siberian necropolis near the village of Zeleniy Yar, at the base of a peninsula local people called "the end of the Earth."

The archaeologists found 34 shallow graves with seven male adults, three male infants, and one female child wearing a copper mask. Buried with a hoard of artifacts, most of the bodies had shattered or missing skulls, and smashed skeletons.

Five mummies were unearthed still shrouded in copper and blankets of reindeer, beaver, wolverine or bear fur, while three copper masked infant male mummies were found bound in four or five copper hoops two inches wide.

The best preserved mummy was a red-haired man found in a wooden sarcophagus. He was covered chest to foot in copper plate and was laid to rest with an iron hatchet, furs and a bronze head buckle depicting a bear.

"Nowhere in the world are there so many mummified remains found outside the permafrost or the marshes," Natalia Fyodorova, of the Ural branch of the Russian Academy of Sciences, told the Siberian Times.

The soil at the site is sandy and not permanently frozen. Scientists have determined that the mysterious people were mummified by accident due to a dip in temperatures in the 14th century. The copper may have also prevented oxidation of the remains.

Intriguingly, the legs of the dead all point toward the nearby Gorny Poluy River. According to Fedorova, such posture might have had a religious meaning. However, archaeologists admitted the graves feature burial rites they had never seen before.

Excavation was halted in 2002 following objections by local people who feared the archaeologists disturbed the souls of their ancestors. But work has resumed now.

"It is a unique archaeological site. We are pioneers in everything from taking away the object of sandy soil, which has not been done previously," Fyodorova said.

Read more at Discovery News

This Supernova Remnant Cranks Up the Heat

When a really massive star — that is, one at least ten times more massive than our sun — reaches the end of its life and runs out of hydrogen to fuse inside its core, it certainly doesn’t go quietly into the night. Instead it explodes as a supernova (specifically a Type II supernova), violently casting off its outer layers and scattering star-forged elements throughout space, briefly outshining all other stars in its galaxy.

The steadily-expanding shells of gas and star-stuff created in the explosion remain visible long after the supernova occurs. These supernova remnants glow brightly in many wavelengths of light — some visible to our eyes, most not — each relating to specific temperatures and elements found in the cast-off debris.

As it plows through space at supersonic speeds the shockwave from the supernova remnant also interacts with interstellar material, clearing it away, compressing it, and causing it to glow as well.

Using data from NASA’s Chandra X-ray Observatory and ESA’s XMM-Netwon, astronomers have identified one such remnant in our galaxy that has swept up a surprisingly large amount of material. Named G352.7-0.1, this supernova remnant is located 24,000 light-years away in the constellation Scorpius. It has pushed aside the equivalent of 45 solar masses — that’s 45 suns’ worth of interstellar “stuff,” not including the mass of the original star.

Watch a video tour of G352 here.

It’s estimated that the G352 supernova occurred about 2,200 years ago, and supernova remnants of that age typically shine brightest from to the material they are blasting aside. But G352 still predominantly glows from its original cast-off debris (“ejecta”) which has remained extremely hot — like 30 million degrees Celsius hot — and shines brightly in x-rays (seen above in blue).

These observations suggest a “unique evolutionary scenario” for G352 wherein a very massive star’s eruption interacted with a surrounding dense molecular cloud, a hypothesis supported by the shell-like shapes of the infrared and radio emissions (seen in orange and purple).

The various shapes of G352′s shells earns it the title of a “Mixed-Morphology Galactic Supernova Remnant,” or MMSNR, further proof that stars don’t all die the same death.

Read more at Discovery News

Rare Night-Shining Clouds Becoming More Common

Rare night-shining clouds that glow across the edge of space tend to appear near Earth's poles. But since the turn of the century, these silvery clouds have become more frequent sights over lower latitudes, including southern Canada and the northern United States, new research finds.

Also known as noctilucent clouds, night-shining clouds are the highest clouds in Earth's atmosphere. They hover around 50 miles (80 kilometers) above the surface of the planet — high enough to reflect sunlight long after sunset. The wispy clouds were first officially documented in 1885. Since 2007, scientists have been monitoring the phenomenon near the poles with NASA's Aeronomy of Ice in the Mesosphere (AIM) satellite.

"AIM and other research has shown that in order for the clouds to form, three things are needed: very cold temperatures, water vapor and meteoric dust," study author James Russell, an atmospheric and planetary scientist at Hampton University in Virginia, said in a statement from NASA. "The meteoric dust provides sites that the water vapor can cling to until the cold temperatures cause water ice to form."

The clouds are most commonly spotted from Earth's higher latitudes during the summer months (when the coldest layer of the atmosphere is actually most frigid). But in recent years, there have been more reports of night-shining clouds over midnorthern latitudes, between the 40th and 55th parallels.

Previous studies have suggested that the increase in night-shining clouds could be linked to rocket launches or an increase in methane emissions, thought to boost the abundance of water at the top of Earth's atmosphere.

Russell and his colleagues wanted to check if this increase was linked to any systematic changes in the atmosphere. They modeled the occurrence of noctilucent clouds at lower latitudes from 2002 to 2011 using actual observations of the clouds as well as historical data on water vapor and temperature conditions in the upper reaches of Earth's atmosphere.

The analysis showed that the presence of noctilucent clouds indeed increased during that decade-long span and that high-altitude temperature decreases seemed to be driving the uptick, the researchers concluded in their study in the Journal of Geophysical Research: Atmospheres.

Read more at Discovery News

Apr 15, 2014

The Surprising Gut Microbes of African Hunter-Gatherers

Hadza women cook tubers they’ve foraged throughout the day. Compared to the men, who spend their day hunting game, the women have more gut bacteria for breaking down fibrous veggies.
In Western Tanzania tribes of wandering foragers called Hadza eat a diet of roots, berries, and game. According to a new study, their guts are home to a microbial community unlike anything that’s been seen before in a modern human population — providing, perhaps, a snapshot of what the human gut microbiome looked like before our ancestors figured out how to farm about 12,000 years ago.

“There have been relatively few studies of gut microbiota among humans eating pre-industrial diets, relative to humans eating post-industrial ones,” said Lawrence David, a microbiologist from Duke University, who was not a part of the study. The new study, published today in Nature Communications, is timely and important, David says, because it provides a snapshot of pre-industrial human’s gut microbiota. It also indicates that the ecosystem in our guts adapts not only to our diets but to the environments we live in.

Researchers have known for decades that the biota in our gut vary depending on what we eat. But the Hadza microbiome still turned out to be surprisingly different.

To study the difference between the ancient and modern gut, researchers analyzed stool samples from 16 Italian urbanites and 27 Hadza foragers, of both genders.

The Italians’ gut flora was generally what they expected in Western diets, with some Mediterranean influences. The Hadza’s poop, however, was like stepping into a lost continent of microbe biodiversity. ”The Hadza gut mibrobiome has an entirely unique combination of bacteria from any western population, or rural African population, that’s been sampled,” said co-author Alyssa Crittenden, a nutritional anthropologist from the University of Nevada, Las Vegas.

Many of the bacteria are species that the researchers had never seen before. And even familiar microbes were present in unusual levels in the Hadza belly. “The Hadza not only lack the ‘healthy bacteria,’ and they don’t suffer from the diseases we suffer from, but they also have high levels of bacteria that are associated with disease,” Crittenden said.

Wiggum plots showing the relative abundance and diversity of gut biota from different cultures. The Hadza’s doesn’t just have unexpected amounts of known bacteria, it has many species that have never been observed before.
In westerners, Bifidumbacterium is a microbe that many nutrition scientists thought was essential to good gut health, but it is almost completely absent in the foragers. Likewise, high counts of the bacteria Treponema have been linked to maladies like Crohn’s disease and irritable bowel syndrome. Neither of these diseases exist among the Hadza, but their guts contain abundant Treponema.

Modern humans have only spent 5 percent of our history as farmers. Before that, most of our species were foragers of some type or other. ”Studies like this one are rare opportunities for generating hypotheses about the bacteria that are most sensitive to diet and metabolism in the gut,” said David. The Hadza’s stomachs represent a reference ecosystem for comparing our modern lifestyles.

That’s not to say you should start stocking up on exotic roots, berries, and wild game hoping to create the perfect balance of beneficial bacteria for your belly. Crittenden and her research partners warn against turning their research into a diet, even if the link between the Hadza’s gut microbiome and their lower rates of gastrointetinal illness prove true. “Even if you try to emulate the diet of the Hadza, you’re not living in the environment,” explained Amanda Henry, a dietary ecologist from the Max Planck Institute in Germany, and a co-author of the study. “There are transfers from the soils, from the animals.” In other words, it’s not just what the Hadza eat that contribute to their remarkable gut flora, it’s where and how they are eating it, too.

Read more at Wired Science

Some Monkeys Are (Really) Monogamous

Unlike many humans, some monkeys are genuinely faithful to their mates.

A species known as Azara's owl monkeys tends to be monogamous, according to a new study of these primates. The research also found that the monkeys' inclination to be faithful was related to the male monkeys' tendency to care for their offspring.

"They [Azara's owl monkeys] live in pairs, so, in a group, we have only one adult male and one adult female, and both of them are faithful," study author Maren Huck, a professor at the University of Derby in England, told Live Science.

"We found a link between... parental care and having few instances of cheating," Huck said.

Researchers had known before this study that members of the Azara's species were socially monogamous, which means that males and females live in pairs. But in animals, including humans, social monogamy is not always equivalent to what researchers call genetic monogamy, where females and males only reproduce with their mates.

True genetic monogamy is in fact extremely rare, the researchers said.

One way researchers can check for genetic monogamy is to analyze the DNA of mating pairs, and check the paternity of the offspring. In the study, the researchers analyzed field observations of the monkeys' behavior, along with genetic samples from a total of 128 monkeys, including some that lived in groups, and others that were solitary "floaters." The material used by the research team included samples from 35 offspring that were born to 17 reproducing pairs.

The researchers found that both male and female monkeys in the study were faithful to their mates, and that all the offspring were indeed genetically related to their male parents.

When males care for offspring, it does not necessarily cause their partners to be monogamous, Huck said, and it is hard to say which came first, but the two may reinforce each other.

It's thought that, in general, a male can gain more by caring for his offspring than by trying to find additional mates. This is especially true in species in which females may be hard for males to find, because of the conditions in which the animals dwell.

The new study may lend an insight into the mechanisms behind pair bonding, which does not necessarily go together with monogamy, and parental mechanisms in other species, including humans.

"Pair bonding — love, if you want — is prevalent in all human societies, whereas fathering is much more variable," study author Eduardo Fernandez-Duque, an associate professor of anthropology at the University of Pennsylvania, said in a statement. "The owl monkey story is suggesting that, under very specific ecological settings, this preference for each other leads to the pair spending a lot of time in close proximity, thus facilitating paternal care and increasing paternity certainty. Genetic monogamy is the result."

Read more at Discovery News

Geologic Wonder: See Grand Canyon from Space

Helicopter tours of the Grand Canyon can provide a bird's-eye view of the iconic landmark. But that's nothing compared to what astronauts see as they zip over northern Arizona in the International Space Station.

In a new image taken from orbit, the Grand Canyon is visible slicing through the Kaibab Plateau, which is part of the expansive Colorado Plateau of Arizona, Utah, Colorado and New Mexico. The photograph was taken by the Expedition 39 crew aboard the ISS on March 25, 2014, according to NASA's Earth Observatory.

In the image, the canyon's forested North and South Rims are visible on either side of the canyon. The popular South Rim, which hosts about 90 percent of the Grand Canyon's 5 million visitors a year, averages about 7,000 feet (2,134 meters) in elevation, according to the National Park Service. The remote North Rim is about 1,000 feet (305 m) higher. Its cooler climes mean that roads to the North Rim are closed October through May each year.

Between the two rims, the Grand Canyon plunges a mile (1.6 km) through layers of schist, sandstone, limestone and more. The Colorado River carved the 227-river-mile (446 kilometers) canyon over millions of years as the Colorado Plateau experienced a tectonic uplift. The amount of time it took to carve the Canyon is a matter of major debate. On one side are researchers who see the canyon as "young" — The gorge as it is today is about 6 million years old, carved out by the Colorado River after it changed course some 11 million years ago. But some research points to sections of the canyon dating back 70 million years. Some researchers see these old sections as evidence of the origin of the Grand Canyon, while others argue that they are in fact "paleo-canyons" carved long ago that the Colorado River simply found and flowed into. Others argue that these sections represent the origin of today's canyon. The debate is intensified by gaps in the geological record and recent, complicated tectonic changes in the region.

Read more at Discovery News

Saturn May Have Given Birth to a Baby Moon

NASA’s Saturn-orbiting Cassini spacecraft has imaged something peculiar on the outermost edge of the gas giant’s A-ring. A bright knot, or arc, has been spotted, 20 percent brighter than the surrounding ring material and astronomers are interpreting it as a gravitational disturbance caused by a tiny moon.

“We have not seen anything like this before,” said Carl Murray of Queen Mary University of London. “We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right.”

The feature in the ring’s edge is approximately 750 miles (1,200 kilometers) long and 6 miles (10 kilometers) wide, but the possible baby moon is likely only half a mile across if it’s confirmed to exist. The observation was made on April 15, 2013, using Cassini’s narrow angle camera and the discovery was announced in a paper published today in the journal Icarus.

Saturn’s moons are icy little worlds and many are thought to have been formed through an agglomeration of material from the extensive ring system that surrounds the planet to this day.

Although there’s the exciting possibility of this new object being the birth of a small satellite, it could also be signs of a small overlooked moon that’s in the process of breaking up. But astronomers are hopeful that this might be the first time we’ve witnessed a baby moon in the process of forming in the solar system. The candidate moon is being nicknamed “Peggy.”

“Witnessing the possible birth of a tiny moon is an exciting, unexpected event,” said Cassini Project Scientist Linda Spilker, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Generally, Saturn’s moons get larger the further their orbits from the planet; over the system of satellites’ history, moons likely migrated from close to the planet, scooping up smaller moons as they drifted further away. As a consequence, Saturn’s rings are depleted of moon-forming material, potentially signalling that Peggy will be one of the last moons to form.

Read more at Discovery News

Apr 14, 2014

Neanderthals and Cro-magnons did not coexist on the Iberian Peninsula, suggests re-analysis of dating

The meeting between a Neanderthal and one of the first humans, which we used to picture in our minds, did not happen on the Iberian Peninsula.

That is the conclusion reached by an international team of researchers from the Australian National University, Oxford University, the UPV/EHU-University of the Basque Country, University of Maryland, Universitat de Girona and the University of Oviedo, after redoing the dating of the remains in three caves located on the route through the Pyrenees of the first beings of our species: L'Arbreda, Labeko Koba and La Viña.

The paper, entitled "The chronology of the earliest Upper Palaeolithic in northern Iberia: New insights from L'Arbreda, Labeko Koba and La Viña," has been published in the Journal of Human Evolution. Until now, the carbon 14 technique, a radioactive isotope which gradually disappears with the passing of time, has been used to date prehistoric remains.

When about 40,000 years, in other words approximately the period corresponding to the arrival of the first humans in Europe, have elapsed, the portion that remains is so small that it can become easily contaminated and cause the dates to appear more recent. It was from 2005 onwards that a new technique began to be used; it is the one used to purify the collagen in DNA tests.

Using this method, the portion of the original organic material is obtained and all the subsequent contamination is removed. And by using this technique, scientists have been arriving at the same conclusions at key sites across Europe: "We can see that the arrival of our species in Europe took place 8,000 years earlier than what had been thought and we can see the earliest datings of our species and the most recent Neanderthal ones, in which, in a specific regional framework, there is no overlapping," explained Alvaro Arrizabalaga, professor of the department of Geography, Prehistory and Archaeology, and one of the UPV/EHU researchers alongside María-José Iriarte and Aritza Villaluenga.

The three caves chosen for the recently published research are located in Girona (L'Arbreda), Gipuzkoa (Labeko Koba) and Asturias (La Viña); in other words, at the westernmost and easternmost tips of the Pyrenees and it was where the flow of populations and animals between the peninsula and continent took place. "L'Arbreda is on the eastern pass; Labeko Koba, in the Deba valley, is located on the entry corridor through the Western Pyrenees (Arrizabalaga and Iriarte excavated it in a hurry in 1988 before it was destroyed by the building of the Arrasate-Mondragon bypass) and La Viña is of value as a paradigm, since it provides a magnificent sequence of the Upper Palaeolithic, in other words, of the technical and cultural behaviour of the Cro-magnons during the last glaciation," pointed out Arrizabalaga.

The selecting of the remains was very strict allowing only tools made of bones or, in the absence of them, bones bearing clear traces of human activity, as a general rule with butchery marks, in other words, cuts in the areas of the tendons so that the muscle could be removed.

"The Labeko Koba curve is the most consistent of the three, which in turn are the most consistent on the Iberian Peninsula," explained Arrizabalaga. 18 remains were dated at Labeko Koba and the results are totally convergent with respect to their stratigraphic position, in other words, those that appeared at the lowest depths are the oldest ones.

The main conclusion -- "the scene of the meeting between a Neanderthal and a Cro-magnon does not seem to have taken place on the Iberian Peninsula" -- is the same as the one that has been gradually reached over the last three years by different research groups when studying key settlements in Great Britain, Italy, Germany and France.

Read more at Science Daily

Does germ plasm accelerate evolution?

Scientists at The University of Nottingham have published research in the journal Science that challenges a long held belief about the way certain species of vertebrates evolved.

Dr Matt Loose and Dr Andrew Johnson who are experts in genetics and cell development in the School of Life Sciences carried out the research, funded by the Medical Research Council (MRC). It suggests that genes evolve more rapidly in species containing germ plasm. The results came about as they put to the test a novel theory that early developmental events dramatically alter the vertebrate body plan and the way evolution proceeds.

The original theory was proposed by Dr Johnson over 10 years ago. His view is that the relationship between the germ line (hereditary germ cells that create sperm and eggs) and the soma (cells which form the body of an organism) also impacts on species diversity. He argues that once a species evolves a substance called germ plasm, germ cells are independent of other cells, so constraints on somatic development are liberated and this enhances a species' ability to evolve. As a result, he says, vertebrates such as frogs, fruit flies and birds, which look unlike their ancestors, came about, and remarkably they evolved much faster than their ancestors did.

Taking a new look at embryology

Early in animal development a subset of cells in an embryo becomes committed to produce Primordial Germ Cells (PGCs). PGCs develop into sperm or eggs. The remaining cells develop as the soma, a term that describes all of the tissues that make up an individual's body. The germ line is an immortal cell lineage, passed on from generation to generation, and charged solely with producing a new embryo at fertilisation. The soma, on the other hand, dies off in every generation. In the most classic biological sense its job is to interpret the effects of natural selection in order to determine genetic fitness, leading to so called 'survival of the fittest'.

There are two known ways to make a PGC. There is preformation -- material in the egg called germ plasm is inherited directly by a few cells in the embryo, and germ plasm instructs these cells to become PGCs. Alternatively, PGCs can develop without germ plasm. In this case PGCs can be induced to form by signals secreted from other cells, which are part of the soma. This is called epigenesis.

Dr Johnson said: "Biologists are accustomed to thinking about how adult somatic traits impact natural selection and the evolution of new species. What is much less clear is the role of embryological mechanisms in evolution, and how they might contribute to species diversity."

A new computer programme tested their hypothesis In this latest publication Dr Loose put this theory to the test. He said: "To investigate the effect germ plasm has on sequence changes we had to look at as many sequences as possible -- nearly 12 million sequences were analysed and processed from 165 different species including mammals, reptiles, amphibians and fish."

With graduate student Teri Evans, Dr Loose wrote computer programmes to process these sequences and test the hypothesis. They compared DNA sequences from species that contain germ plasm with related species that use epigenesis instead. So, for example, they compared DNA from salamanders (epigenesis) with frogs (germ plasm), both of which are amphibians. Unexpectedly, they found that species with germ plasm have a faster rate of sequence change than those without. Thus, frogs evolve faster than salamanders. Similar comparisons with fish and reptile species identify the same pattern, suggesting it is a generalised feature of animal evolution. These results support the theory that germ plasm provides a selective advantage because it enables more rapid evolution. In addition, they support the view that the relationship between development of the germ line and soma shapes species diversity in the animal kingdom.

Dr Johnson said: "What Matt and I have been working on would not normally have been predicted. This paper shows that animals can evolve more rapidly with germ plasm. Typically evolution is thought to be a gradual process, but this work suggests that the evolution of germ plasm can lead to explosive radiations of species. Importantly, because of the accelerated rate of evolution, genetic similarities between species can differ from that expected from their phylogenetic relationships. This has broad implications across biological disciplines."

Read more at Science Daily

How Flesh-Eating Strep Bacteria Evolved Into an Epidemic

Bacteria aren’t kind enough to leave behind a fossil record (save for cyanobacteria), but they’re evolving fast. Really fast. Their short life cycles mean that generations come rapid-fire, adapting through natural selection into the monster pathogens that are currently shrugging off our finest antibiotics.

It’s all the more troubling when we’re dealing with the flesh-eating variety. A new study, published today in the Proceedings of the National Academy of Sciences, details the evolution of one such bacteria, group A Streptococcus. By charting its evolution, scientists hope to gain invaluable insights into tackling subsequent generations of these menaces, and to begin to better understand the very nature of epidemics.

You’ve probably caught a strain of group A Streptococcus before, manifesting itself as strep throat. But depending on your immune system and the strain of Strep, you can be affected in many different ways, some of them fatal. “So you can get infections of muscles, you can get infections of cardiac valves, it can go to bone,” said physician Paul Sullam of the University of California, San Francisco Medical Center, who wasn’t involved in the study. “It can also get into your bloodstream. And when it does, it can produce this generalized disturbance of your cardiac function and lung function, something we call septic shock.” It can also lead to something called necrotizing fasciitis, the horrific destruction of soft tissue.

Strep wasn’t always so virulent and aggressive. Back in the early 1980s, it suddenly ramped up into into an epidemic, which continues to this day. And thanks to this new study, we now know exactly how that happened.

Scientists sequenced the genomes of thousands of strains of group A Strep in the biggest bacterial study of its kind to date. What they found was that, incredibly, only four tiny modifications to group A Strep caused it to explode into a worldwide epidemic.

“The first two events were the acquisition of two bacterial viruses,” said infectious disease pathologist James Musser of the Houston Methodist Research Institute, one of the authors of the paper. “Bacteria, just like humans, can get infected by viruses.”

Sometime in the 1980s, these viruses infected a single bacterial cell of group A Strep, transferring genes to the bacterium that allowed it to produce novel toxins. This is known as horizontal gene transfer, the acquisition of a trait not by mutations in reproduction, but from an outside source. Indeed, according to Sullam, “more common in this particular organism is it imports genetic material from other sources, predominantly by bacteriophages,” the viruses that infect them.

The third event was a regular old mutation in the genes of the bacteria, which produced an upgraded variant of one of the toxins. The fourth and final event that immediately preceded the epidemic was an attack from another virus, which had previously attacked another strain of group A Strep, picking up some of its genetic material. When it hit the epidemic strain, it transferred this material, which encoded two additional toxins and caused the strain to churn them out in massive quantities.

“This whole process ultimately resulted in two important character changes to the organism, which were the ability to cause an increased number of infections, and an increased severity of infection,” Musser said. Then you’re off and running with an epidemic.”

Read more at Wired Science

Sharks Contain More Pollutants Than Polar Bears

Greenland sharks joined the list of top Arctic predators that suffer under heavy loads of accumulated pollution in their bodies.

Biologists already knew that polar bears, orcas (killer whales) and people build up dangerous levels of toxins from feeding at the top of the Arctic food chain. Now, marine scientists have found evidence that a certain population of Greenland sharks (Somniosus microcephalus) could be one of the most contaminated Arctic predators.

Greenland sharks living near the Svalbard Islands, a Norwegian territory far to the north of Scandanavia, contained high levels the pesticides DDT and chlordane and the industrial chemical PCB, according to a study published last year in Science of the Total Environment.

These chemicals, collectively known as persistent organic pollutants (POPs), were banned or restricted in the United States and 90 other nations in a 2001 treaty. However, POPs don’t break down quickly in the environment. Instead, they build up over time in the food web, a process known as bioaccumulation.

POP particles stick to vegetation and microorganisms that animals eat, or are ingested directly. Then the chemicals stay in the food chain and build up as one creature devours another.

In the case of sharks near Svalbard, scientists suggested that the predators were more contaminated because they ate more seals than other Greenland shark populations. The seals contained higher levels of POPs than other prey, because the POPs in each fish the seals ate subsequently became trapped in the seals’ fat. When the sharks ate the seals, the POPs continued to build up.

Previous research on Greenland sharks from near Iceland and the Davis Strait in Canada found lower levels of POPs, likely because these sharks ate fewer seals.

Liver samples from the Svalbard seal-eating sharks revealed lower than normal levels of Vitamin A and higher levels of Vitamin E, which may have been a biological defense reaction to the POPs.

“We can conclude that the contaminants lead to reduced levels of vitamin A and increased levels of vitamin E in the sharks around Svalbard, but we don’t know if this affects their health or reproduction,” study co-author Bjørn Munro Jenssen of the Norwegian University of Science and Technology said in a press release. “We would have to study the species for many years.

“It seems that animals mobilize vitamin E stored in the liver and send it into the blood stream. Greenland sharks seem to be able to do this when needed. Lower levels of vitamin A in the body lead to a reduced immune defense and may affect reproduction negatively,” Jenssen said.

Jenssen noted that sharks in other areas may be even more contaminated.

“Seals living along the coast in Trøndelag in mid-Norway have pollutant levels five times higher than those in seals around Svalbard,” said Jenssen. “In the Oslo fjord the levels are ten times higher.”

Read more at Discovery News

Apr 13, 2014

Pluto May Have Deep Seas and Ancient Tectonic Faults

In July 2015 we get our first close look at the dwarf planet Pluto and its moon, Charon -- a fact that has scientists hypothesizing more than ever about what we might see there.

One of the latest ideas put forward is that perhaps the collision that likely formed Pluto and Charon heated the interior of Pluto enough to give it an internal liquid water ocean, which also gave the small world a short-lived plate tectonics system, like that of Earth.

“We predict that when New Horizons gets there it will see evidence of ancient tectonism,” said Brown University's Amy Barr, coauthor of a new paper with Geoffrey Collins in the latest issue of the journal Icarus. By 'ancient' Barr means sometime way back during the first billion years of the solar system's history.

Pluto Antifreeze?

Barr and Collins modeled the Pluto-Charon system based on the idea that the initial collision of the two bodies would have generated enough heat to melt the interior of Pluto creating ocean that would have survived for quite a while under an icy crust.

“Once you create an ocean on an icy body it's hard to get rid of it,” said Barr. That's because as the ocean freezes, the remaining liquid portion gets enriched with salts and ammonia -- which serve as antifreeze.

Next comes the part where that ocean could have created icy tectonic plates on Pluto's surface.

“One thing that we know is the angular momentum will be conserved as the system evolved,” said Barr. With that fact, they simulated a bunch of scenarios based on where Charon's orbit was right after the collision -- since nobody actually knows where Charon started. Then in each scenario they saw Charon's orbit gradually migrate outward -- just like the moon's orbit did around Earth.

When Pluto and Charon were closer and still hot from their collision they pulled more forcefully on each other and were more egg-shaped as a result. But as Charon moved away, Pluto became more spherical. But to change shape, the icy surface would have had to crack and create faults -- telltale signs of tectonics.

“In the scenarios we see, you generate more than enough stress to create all kinds of tectonic features,” Barr said.

Tectonic Features

But will New Horizons see those faults? Probably, says Jeffrey Moore, the head of New Horizon's geology and geophysics imaging team at the NASA Ames Research Center.

“It would probably be surprising if we didn't see tectonism,” said Moore.

One potential complication is Pluto weather. Telescopes discovered years ago that Pluto has an atmosphere when it is at its closest approach to the sun, and then that atmosphere freezes to the surface when Pluto is on the more distant part of its elliptical orbit. That regular change could be enough to erode the surface of Pluto to the point where it might hide the tectonic features.

“It's not inconceivable that the tectonics are eroded and covered up by sediments,” said Moore. But he doubts that will be the case, pointing to examples of worlds with atmospheres that freeze to the surface seasonally -- like Jupiter's moon Callisto.

Read more at Discovery News

Ancient Daddy Longlegs Had Extra Eyes

A 304-million-year-old fossil discovered in Eastern France shows primitive living harvestmen -- more commonly called daddy longlegs -- had one more pair of eyes than they do today.

The ancient harvestmen had a pair of eyes along the middle of the body -- like their modern counterparts -- but they also had a pair of eyes on the side of the body. The findings were reported by researchers from the American Museum of Natural History and the University of Manchester, in the journal Current Biology.

Scientists studied the fossil using high-resolution X-ray imaging at the Natural History Museum, London.

"Our X-ray techniques have allowed us to reveal this fossil in more detail than we would have dreamed possible two decades ago,” said Russell Garwood, a research fellow at the University of Manchester and a lead author on the study, in a release.

Though Harvestmen have eight legs and are categorized as arachnids, they're not spiders. They're more closely related to scorpions.

Read more at Discovery News