Apr 18, 2014
"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
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
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.
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
|When threatened, Cephalotes ants will leap from a branch and glide themselves right back to the trunk. This little guy was … encouraged to demonstrate.|
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.|
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.”
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.|
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
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
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.”
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
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.”
"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
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
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
“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