Jun 14, 2014
Published today in Science, researchers from the Wellcome Trust Centre for Human Genetics and the Biomedical Primate research Centre in the Netherlands looked at whether, in chimpanzees, there was a heightened risk of fathers passing on mutations to their children compared to humans.
In humans, each individual inherits, on average, about 70 new mutations from their parents. However, this number is influenced by paternal age such that older fathers tend to result in more mutations -- in humans each extra year of age results in two extra mutations.
Mutation risk is linked to father's age because the sperm lineage in males keeps dividing, while females have all the eggs they are ever going to produce present at birth. Paternal age is an established risk factor in a number of disorders including schizophrenia and autism.
The study found that the number of new mutations inherited by chimpanzees from their parents is, on average, very similar to that in humans, but that the effect of the father's age is much stronger -- each additional year of father's age results in three extra mutations.
The results suggest that sexual selection can influence the rate of evolution through its effect on the male mutation rate.
Professor Gil McVean, from the Wellcome Trust Centre for Human Genetics at the University of Oxford said: "In humans, a father's age is known to affect how many new mutations he passes on to his children, and is also an established risk factor in a number of mental health disorders.
"This study finds that in chimpanzees the father's age has a much stronger effect on mutation rate -- about one and a half times that in humans. As a consequence, a greater fraction of new mutations enter the population through males, around 90 per cent, compared to humans, where fathers account for 75 per cent of new mutations."
In the study, Wellcome Trust-funded researchers sequenced the genomes of nine western chimpanzees from a three generation family living at the biomedical primate research centre in the Netherlands.
To establish the number of new mutations a child inherits researchers sequence children and their parents and compare the genetic sequence -- any change in the sequence that doesn't exist in either parent genome is a new mutation. To find out which parent the mutation comes from you need to sequence members of the next generation of the family.
Read more at Science Daily
Widely believed to be a native of the Americas, the black soldier fly (Hermetia illucens) thrives on decaying organic material. It was thought to have first reached Europe in the early 1900s.
“We can now prove the insect was present in Europe several centuries before,” Gino Fornaciari, professor of history of medicine and professor of paleopathology and funerary archaeology at the University of Pisa, told Discovery News.
“Indeed we found a larva in the sarcophagus of the Italian princess Isabella of Aragon, who died in 1524,” he added.
Isabella, the daughter of King Alfonso II of Naples, married her first cousin, the Duke of Milan Gian Galeazzo Sforza, in 1489.
For the occasion, Leonardo Da Vinci, who had been working in Milan as the court artist since 1482, orchestrated a magnificent party with plays, robots and fountains. Some art historians now argue that Isabella, and not Lisa Gherardini Del Giocondo, was the sitter for the Mona Lisa.
Her husband was never able to rule, because his uncle, Ludovico, confined Gian Galeazzo and Isabella in a castle-prison in Pavia. Isabella, who complained that her marriage was historically bad, remained there until her husband died suddenly at 25, possibly poisoned by Ludovico.
She then returned to Naples and finally died there at the age of 54, likely poisoned by her own medicine to treat syphilis.
According to Fornaciari, who exhumed her body, Isabella’s teeth were covered by a black patina which was intensively and intentionally abraded.
The black color was produced by mercury, the drug she was given in massive doses to treat -- ineffectively -- her syphilis.
Among her remains, near the skull, the researcher found two body parts belonging to a fly larva, which was identified as a black soldier fly.
Often confused with a wasp, this insect is well known in forensic entomology as it dominates decaying bodies.
“It is highly unlikely the black soldier fly reached Isabella’s body centuries after her death,” wrote Fornaciari, along with Giovanni Benelli, an entomologist at Pisa University, and colleagues in the Journal of Archaeological Sciences.
The sarcophagus was previously opened by thieves when the body was already skeletonized, making it unsuitable for the black soldier fly.
The finding raises new questions about the origin of this insect. According to the researchers, there are three possible scenarios.
Read more at Discovery News
Jun 13, 2014
Exploiting the middle ground as a strategy may have helped dinosaurs rule the Earth for more than 100 million years, scientists report today in the journal Science .
The question of whether dinosaurs were lumbering cold-blooded or active warm-blooded animals has been debated for decades, but finding a definitive answer has proven difficult.
Now, biologist John Grady from the University of New Mexico and colleagues, have developed a new method for analysing dinosaurs' metabolic rates.
Building on previous work by palaeontologists and physiologists, they created a large database on growth and energy in both living and extinct groups of vertebrates including 21 species of dinosaurs.
They then used statistical analyses and energetic models to determine the relationship between growth rate and energy use.
Annual growth rings in fossils were used to determine growth rates, while metabolic rates were estimated by using changes in body size as an animal grows from birth to adult (known as ontogenetic growth).
"We found that growth rate is a good indicator of energy use in living animals. Warm-blooded (endothermic) mammals grow 10 times faster than cold-blooded (ectothermic) reptiles, and metabolise 10 times faster; in general doubling one's metabolic rate leads to a doubling in growth rate," Grady explains.
However, when they examined the growth rates of dinosaurs, although there was some variation in the rate they grew, they had neither the high metabolic rate of mammals and birds, nor the low metabolic rate of reptiles.
"Surprisingly we found that, instead, they occupied the middle energetic ground."
Today, mesothermic animals are uncommon, but living species come from across the evolutionary spectrum, and include leatherback turtles, tuna, great white sharks and the echidna.
These animals at times rely on internally-generated metabolic heat to maintain body temperatures, while being subject to external temperatures in others.
"They generate enough heat to warm their blood above ambient temperature, but don't do anything to maintain it, such as shivering which humans do when they are cold," says Grady.
"Meanwhile, echidna body temperatures can fluctuate by up to 10 degrees when they are active."
Dinosaurs evolved around 200 million years ago, and competed for resources with ectothermic animals like lizards.
Their higher metabolic rate meant they could move faster making them a more dangerous predator, or more elusive prey, says Grady.
"A higher metabolic rate gave them other competitive advantages as well: they could grow faster and reproduce faster.
"But being completely warm-blooded like a mammal limits the maximum size an animal can reach — it is doubtful that a lion the size of T. rex would be able to eat enough wildebeasts (or elephants) without starving to death.
"With their lower food demands, however, the real T. rex was able to get really big while still maintaining their advantage over their competition."
As well as helping us understand how warm-blooded animals evolved, understanding dinosaurs' energy use challenges our understanding of how life operates, Grady explains.
Read more at Discovery News
The video was soon definitively debunked; it was not a hoax nor faked, but nor was it what it was claimed to be. A 9/11 conspiracy theorist "truther" had reviewed the footage and while slowing down and manipulating the video, decided that there was something suspicious about that footage: part of a plane seemed to disappear before impact.
Researcher Mike Hall analyzed the video "proof" and discussed the results on a podcast called Skeptics with a K (as distinguished, for example, by "sceptics" who populate countries who use the Queen's English). As Slate writer Scott Huler explained, Hall found that the hijacked plane "disappeared exactly the way you disappear when you step behind a tree: The building came between the camera and the airplane. The building is a good six blocks south of the tower—in front of it, not behind it. The single supposed fact on which the video based its 2 million–hit paranoid parade was provably wrong, in minutes."
Interestingly, it did not occur to the conspiracy theorist that the video he was analyzing might have been faked or inaccurate in some way; in classic conspiracy thinking, one video that seems to show something different than dozens of others (not to mention thousands of eyewitness accounts) is hailed as the one true and accurate evidence.
Sharing the Conspiracy
So what explains the wild popularity of the video? Part of the answer lies in the unquenchable thirst for conspiracy theories, and the fact that they are impervious to debunking. 9/11 conspiracies, in part because they trade on politics and what was arguably America's greatest tragedy, are not going away any time soon.
While certain specific claims central to conspiracy theories can be, and have been, disproven (ranging from Barack Obama's "faked" birth certificate to Osama bin Laden's "faked" death to the appearance of supposedly dead Sandy Hook school shooting victims), conspiracy theories themselves, for the most part, are immune to debunking. True believers will dismiss any information that proves them wrong as simply a part of the cover-up. It's a closed information system, a self-reinforcing echo chamber that insulates beliefs from skeptical analysis.
Though the casual ambivalence with which this patently false conspiracy misinformation video spread through social media is concerning, it's important not to overstate its influence. Though the video was made by a conspiracy theorist, just because nearly 3 million people saw and/or shared the video does not mean that they endorsed it; most just passed it along as another "interesting" video, which for all they cared might as well have been of a kitten astonished by a mirror.
In fact many—perhaps most—people probably didn't get past the headline. Research has found that most people don't actually bother to read what they share on Facebook or Twitter. As a Time magazine piece (that I didn't read every single word of) notes, "Just because a story gets a lot of tweets doesn’t mean people are reading it.
"Chartbeat, a company that measures real-time traffic for websites, says its data indicate that many people only spend a few seconds on an article page before tweeting it out. Chartbeat measures things like how far people scroll down, amount of time spent on a page and where they click next in order to determine whether people are actually reading content. 'We've found effectively no correlation between social shares and people actually reading,' Chartbeat CEO Tony Hailie tweeted."
Thus it's easy to overestimate the influence of these conspiracy videos when the psychology of social media plays a bigger role. In fact, the public ambivalence seen in the social sharing of the video (reflected in accompanying messages such as "I don't know if it's real, but check this out..." or "Something to think about...") is typical of conspiracy theory propaganda, which often includes disingenuous disclaimers along the lines of "I'm not saying it's true, just asking questions!"
In both cases the effect is the same: the "disclaimers" allow both conspiracy theorists and non-conspiracy theorists to spread misinformation and speculation under the guise of sharing an outrageous claim without having to formally and personally vouch for its validity.
Slate's Huler reminds readers "to think-- and above all check -- before you share. If it's a lie, by perpetuating it you claim at least a portion of the responsibility."
Read more at Discovery News
The results of the study will help scientists understand Earth's water cycle, and how plate tectonics moves water between the surface of the planet and interior reservoirs, researchers say.
The Earth's mantle is the hot, rocky layer between the planet's core and crust. Scientists have long suspected that the mantle's so-called transition zone, which sits between the upper and lower mantle layers 255 to 410 miles (410 to 660 kilometers) below Earth's surface, could contain water trapped in rare minerals. However, direct evidence for this water has been lacking, until now.
To see if the transition zone really is a deep reservoir for water, researchers conducted experiments on water-rich ringwoodite, analyzed seismic waves travelling through the mantle beneath the United States, and studied numerical models. They discovered that downward-flowing mantle material is melting as it crosses the boundary between the transition zone and the lower mantle layer.
"If we are seeing this melting, then there has to be this water in the transition zone," said Brandon Schmandt, a seismologist at the University of New Mexico and co-author of the new study published today (June 12) in the journal Science. "The transition zone can hold a lot of water, and could potentially have the same amount of H2O as all the world's oceans." (Melting is a way of getting rid of water, which is unstable under conditions in Earth's lower mantle, the researchers said.)
A water-rich mineral
Ringwoodite is a rare type of mineral that forms from olivine under very high pressures and temperatures, such as those present in the mantle's transition zone. Laboratory studies have shown that the mineral can contain water, which isn't present as liquid, ice or vapor; instead, it is trapped in the ringwoodite's molecular structure as hydroxide ions (bonded oxygen and hydrogen atoms).
In March, another research group discovered an unusual diamond from the mantle that encased hydrous ringwoodite. Though the find suggested the transition zone could contain a lot of water, it was the first and only ringwoodite specimen from the mantle scientists have ever analyzed (all other samples were produced in the lab or found in meteorites), and may not be representative of other mantle ringwoodite.
"Right now, we're one-for-one, because that ringwoodite had some H2O in it, but we didn't know if it was normal," Schmandt told Live Science. So Schmandt and geophysicist Steven Jacobsen of Northwestern University in Illinois set out to observationally test if other mantle ringwoodite also contains water.
The researchers knew the crystal structure of ringwoodite allows the transition zone to hold water, but that structure changes if the material moves across the boundary to the lower mantle (due to increasing pressures and temperatures). Because the structure of minerals in the lower mantle can't trap water the way ringwoodite can, Schmandt and Jacobsen reasoned the rocks would melt as they flowed from the transition zone to the lower mantle. "Melting is just a mechanism of getting rid of the water," Schmandt said.
To test this hypothesis, Jacobsen and his colleagues conducted lab experiments to simulate what would happen to transition zone ringwoodite as it travels deeper into the Earth. They synthesized hydrous ringwoodite and recreated the temperatures and pressures it would experience in the transition zone by heating it with lasers and compressing it between hard, anvil-like diamonds.
Using their setup, they then slowly increased the temperature and pressure to mimic the conditions in the lower mantle. The ringwoodite transformed into another mineral called silicate perovskite, and transmission electron microscopy showed that the mineral contained silicate melt around single crystals of perovskite.
"What that tells us is if there is similarly hydrated ringwoodite in the transition zone that's dragged down, we would expect it to produce melt," Schmandt said. "Because melt changes how seismic waves propagate, that's a target I can hunt for [with seismometers]."
Finding the melt
Using the Earthscope USArray, a network of portable seismometers across the United States, Schmandt analyzed seismic waves as they passed from the transition zone to the lower mantle. He found the waves slowed as they crossed into the lower mantle, suggesting that melt was present in the boundary. Importantly, the decrease in seismic velocity didn't happen everywhere — models showed the wave velocity decreased only where material was flowing downward from the transition zone to the lower mantle, as the researchers predicted. [Infographic: Earth's Tallest Mountain to Its Deepest Ocean Trench]
The melt produced in the boundary likely then flows back upward, returning to minerals that can hold the water, Schmandt said, adding that this mechanism allows the transition zone to be a stable water reservoir.
"[The study] provides critical experimental support for the important role that the transition zone plays in controlling the melting behavior and flux of hydrogen in the deep Earth," Graham Pearson, a mantle geochemist at the University of Alberta, who wasn't involved in the work, told Live Science in an email.
Anna Kelbert, a geophysicist at Oregon State University who also wasn't involved in the study, notes that scientists have previously used numerous approaches to look for evidence of Earth's interior water reservoir, but this is the first time researchers have searched for clues of the reservoir by focusing on the potential water-induced melting at the bottom of the transition zone. "It provides an important multidisciplinary perspective on this problem," Kelbert said. "It has important implications on our understanding of the behavior of subducting slabs deep in the mantle, and on our understanding of overall water budget/distribution in the Earth."
Read more at Discovery News
|The lion’s mane jellyfish only looks like a lion’s mane if you squint really hard and pretend that lions have tentacles and live in the ocean. And have translucent heads.|
McPherson’s colleague, a mercurial fellow named Ian Murdoch, becomes a person of interest. He had, after all, once thrown McPherson’s dog through a plate glass window. But that suspicion falls to pieces when the dog-hurler himself staggers into Sherlock’s home in comparable agony, all marked up with the same red lines.
And then the answer hits the great detective. With a police inspector and a guy named Stackhurst he hurries to the beach and finds the culprit: “Cyanea!” he cries. “Cyanea! Behold the Lion’s Mane!” It’s a great jellyfish among the rocks. Shouts Sherlock: “It has done mischief enough. Its day is over! Help me, Stackhurst! Let us end the murderer forever.” And with that they push a boulder into the water, crushing the critter.
That’s a whole lot of animal cruelty in a single short story, and the severity of a sting from a lion’s mane jellyfish, known scientifically as Cyanea capillata, is highly exaggerated here. But this critter is actually far more remarkable than its fanciful villainization. What Sherlock failed to mention is that this is the world’s largest jellyfish, with a bell that reaches a staggering 8 feet wide and tentacles that grow to 120 feet long, far longer than a blue whale. And this monster is really, really loving the whole global warming thing, conquering more and more of Earth’s oceans in massive blooms. So please, if you will, welcome our new giant gelatinous overlords.
|“Hey, kids? Do me a solid and keep your hands off of me.”|
Lion’s manes will take just about anything, from the tiniest zooplankton—little critters and fish larvae and such that drift in the open ocean—to smaller jelly species and even their own kind. Their mighty weapons are stinging cells known as nematocysts, which on contact fire poisonous barbs into the prey (think Scorpion from Mortal Kombat, only nematocysts didn’t used to get me in trouble for spending so much money in arcades).
Though nowhere near as powerful of the notoriously deadly box jellyfish, the sting of the lion’s mane is more than enough to incapacitate small critters—and dish out searing pain to humans. (Gershwin herself once had a lion’s mane sting her foot, which “went all red and puffy” and felt like it was being stabbed with “thousands of needles.”) Thoroughly ensnared by the tentacle’s innumerable spines and none too healthy on account of the poison, the prey is reeled in. The lion’s mane can do this a single tentacle at a time, contracting the muscles in each until the prey reaches its curtain-like “oral arms,” folds of tissue in its bell.
|The photographer likely suffered greatly to take this picture, but rest easy knowing that we paid for the rights to republish it, so at least he’s getting compensated for his efforts.|
That’s quite an evolutionary sweet spot. Such a sweet spot, in fact, that the lion’s mane never bothered to evolve true eyes. Instead, these jellies have extremely rudimentary eyespots and can do nothing more than detect light and dark—no shapes and certainly no colors (interestingly, box jellyfish have eyes more like our own, complete with lenses and such, presumably so they can observe the terror they strike in humans). And a brain? Not really necessary, as it turns out. They do have nerve bundles that essentially automate all of their processes, but these are nothing like a brain as we would recognize it.
“A brain is kinda overrated, really,” said Gershwin. “We find it kind of entertaining, and a little bit important, but they do all the stuff they need to do without a brain. But so do venus fly traps. Lots of things can actually do kind of sophisticated behaviors without a brain.”
Reproduction for the lion’s mane, though, is quite sophisticated. Males release sperm threads into the water, and females hoover them up with their mouth-anus thing, a totally unscientific term that I just made up. Her eggs are fertilized internally, and when they hatch, the larvae roam around a bit inside her, then drift off to settle on the seafloor.
But these larvae don’t turn right into what we would identify as jellies, in what is known as the medusa stage, named after the mythical lady with snakes for hair. Instead, they become little white tubes with frilly ends called polyps, which wait until conditions are just right to actually clone themselves hundreds of times over, releasing baby jellies into the water column. Though scientists have yet to do genetic testing on this, Gershwin suspects that huge blooms of lion’s mane jellies could in fact all be clones from a single tiny polyp. It’s a bit like Attack of the Clones, only interesting.
And boy have they been blooming. Populations of jellyfish like the lion’s mane seem to be exploding in the world’s oceans—because, bluntly put, we’ve goofed. Global warming, overfishing, pollution, basically anything terrible we’ve done to the seas have been an absolute boon to jellyfish, according to Gershwin. Data on jellyfish populations is scarce, so nothing is yet definitive, but as Gershwin puts it, “we now find ourselves in the unexpected position of knowing that we have serious problems with stings to tourists and cloggings of power plants and salmon kills and whatnot, but really having little idea about the speed and trajectory in terms of long-term view.”
As humans, it’s clear we need to tackle the direness that is global warming, but the lion’s mane and its jelly comrades would really prefer that we didn’t. Not only do jellies grow faster in warmer waters, temperature is a pivotal factor in their reproduction. In some species, polyps will only develop as days grow longer in summer, but others instead wait until the water climbs to a certain temperature. Thus ever-hotter oceans in these times of global warming could make for more blooms.
|Yeah, we didn’t have to pay for this one, so hopefully the photographer is OK.|
And jellyfish are really good at living in oxygen-deprived water. Pretty much everything else in the sea? Not so much. “High-rate breathers,” such as beefy fish that need lots of oxygen to power their muscles, die off when jellyfish lazily cruise around, not the slightest bit fazed.
Then there’s the inflow of our sewage and fertilizers, nutrients that microscopic plants called phytoplankton go ga-ga for. Their populations explode, and are then eaten by their animal counterparts, zooplankton, which are in turn eaten by jellies. But when blooming phytoplankton die and decompose, the bacteria that feed on them suck still more oxygen out of the water.
Read more at Wired Science
Jun 12, 2014
The plants likely fall off here and there, colonizing regions far away from where each of the plant’s journeys began, according to the study, which is published in the journal PeerJ.
For the study, a team of 10 biologists, including three undergraduate students, collected American golden plover feathers in the field and used microscopes to closely examine the feathers.
The researchers found a total of 23 plant fragments that were trapped in the feathers of long-distance migratory birds that were about to leave for South America.
“We really had no idea what we might find,” one of the undergrads, Emily Behling, was quoted as saying in a press release.
The University of Connecticut senior added, “Each feather was like a lottery ticket, and as we got further into the project I was ecstatic about how many times we won.”
Clinging to the feathers were mosses, spores, plant pieces and more. Most are thought to be able to grow into new plants if they fall off, or if the bird knocks them off, in a suitable environment.
For example, about half of all known moss species can self-fertilize to produce offspring. Many can grow as clones. It only takes a single successful dispersal event to establish a new population. This helps to explain why moss might suddenly appear here and there in home gardens.
Co-author and PhD candidate Lily Lewis, also from the University of Connecticut, said, “Mosses are especially abundant and diverse in the far Northern and Southern reaches of the Americas, and relative to other types of plants, they commonly occur in both of these regions, yet they have been largely overlooked by scientists studying this extreme distribution. Mosses can help to illuminate the processes that shape global biodiversity.”
Read more at Discovery News
O.K., they weren’t exactly doing bench presses, but an experiment with horned frogs measured the power of their tongues by placing a tasty cricket behind a glass slide. When the frogs’ tongues shot out at lightning speed to grab the crickets, a transducer attached to the slide recorded the forces exerted by the frog’s tongue.
The South American horned frog is known for its incredible snatching power — it has been observed slurping up whole mice in the wild. A study published in the journal Scientific Reports, suggests the tongue functions similar to sticky tape.
Thomas Kleinteich at the University of Kiel in Germany used four horned frogs purchased from local pet shops. Even these domesticated versions displayed incredible tongue power and speed. The forces measured from their tongues were on average larger than the weight of the frog itself, and more than three times bigger in the case of one of the younger frogs.
“The thing that’s interesting about frog tongues is that they’re really fast,” he told BBC News. “It only takes milliseconds.”
Of course, force, alone, can’t capture a cricket or mouse. That also requires some stick, which, in the case of the frog, comes in the form of mucus. Interestingly, the researchers found that less may be more when it comes to mucus and grabbing power.
“The common belief is… that the mucus acts as some sort of superglue,” Dr Kleinteich told the BBC. “But what we found was actually that we got higher adhesive forces in trials where we found less mucus. That was quite interesting.”
Read more at Discovery News
The fish, named Big Mouth Blunt Tooth (Megamastax amblyodus), is described in the latest issue of Scientific Reports. For its time, the toothy and lobe-finned fish was in the number one spot on the food chain.
"At 1 meter (3.3 feet) in length or greater, it was vastly larger than any other animal," lead author Brian Choo told Discovery News, adding that Big Mouth was "likely the earliest vertebrate (backboned) apex predator in the fossil record."
Choo, a paleontologist at the Chinese Academy of Sciences and Flinders University, and his colleagues analyzed Big Mouth's remains, which were unearthed at the Kuanti Formation in Yunnan, southwestern China. During the fish's lifetime, a period known as the Silurian, this region was part of the South China Sea. It is where the marine ancestors of all jawed animals, including humans, first evolved.
Equipped with both piercing and crushing teeth, Big Mouth likely preyed upon hard-shelled moving species, such as mollusks and armored fishes. The second largest animal at the time, Guiyu onerios -- aka Ghost Fish, was a mere one-third of Big Mouth's size.
Why then was Big Mouth so big?
One reason, according to the researchers, is that competition among fish appears to have been fierce.
Co-author Min Zhu explained, "During the Silurian period, the South China Sea, then at the equator, was the cradle of early jawed vertebrates, thus the ecological competition among these creatures was very intense."
Another reason is that Big Mouth probably had plenty of oxygen. Modern fish are generally worse off in low oxygen conditions, and big fish require more oxygen than small ones, Choo said. Big Mouth therefore could not have existed unless sufficient oxygen was present.
Big Mouth provides strong evidence that near-modern oxygen levels occurred at least 420 million years ago, which Choo said was "a likely byproduct of the spread of plants on land."
"There was life on land during the Silurian, but it certainly wasn't nearly as diverse as today," he continued. "There would have been a variety of low-growing primitive plants growing in moist areas. While there were no trees, there was a towering organism called Prototaxites, possibly a giant fungus, which grew up to 8 meters (26.3 feet) tall."
The only animals on land were backbone-less ones, such as huge sea scorpions that scuttled along the beaches and swamps. There were no flying animals at this time, and sharks weren't around yet either. If additional Big Mouth-sized (or larger) animals did exist, they were probably other fish.
Paleontologist Per Ahlberg is a professor of evolutionary organism biology at Uppsala University. He recently saw the fossils for Big Mouth, and was impressed.
Read more at Discovery News
Missing a lower jaw, the early 16th century artifact was found by a German couple in 1987 in an antique shop.
“It is a small, naturalistic looking, deformed skull of a more than 50-year-old-male and it is made of a partially hollowed stone like material,” wrote independent Belgian researcher Stefaan Missinne in the Wiener Medizinische Wochensschrift, a medical journal published in Vienna.
Milky white with small, brownish-yellow stains, the tiny artifact features remarkable detail. “Detailed eye sockets lead to the inside of the cranium and allow for a ‘view’ of the inside, which is anatomically abnormal,” Missinne said.
According to French skull expert Roger Saban, the object resembles an anatomic drawing known as RL 19057. Housed in the Royal Collection in Windsor Castle, the unpublished drawing shows a similar deformed skull missing a lower jaw.
Despite the extraordinary level of detail, the drawing and the skull both feature the same small anatomical errors, further strengthening the link with Leonardo.
Chemical analysis showed the artifact was made from an agate-based mixture of quartz and gypsum. Leonardo invented this mixture, which he called “mistioni,” between 1503 and 1509. No one else is known to have experimented with this material, which was likely sourced in a mine near Volterra in Tuscany.
The size of the artifact match Florentine measurement units that were used in the Renaissance. “The origin of the skull, leads, therefore, to Florence,” Missinne said.
Read more at Discovery News
Jun 11, 2014
Conspicuously absent for a British production, though, is the banshee of Irish and Scottish mythology, an ugly, nasty hag clad either in white or gray. A kind of fairy, she’s said to soar around your house, screaming like a manic demon to not so subtly let you know you’re about to die, usually in a violent manner. But unlike the Grim Reaper, this lady doesn’t murder you herself. She’s more of a hands-off type of death omen.
A fixture in U.K. myth-telling for some 1,000 years, particularly among elite families with a penchant for making death particularly dramatic, the banshee can also take the form of a beautiful woman weeping instead of wailing, all upset about your looming death. Also known as the Washer of the Ford, she can sometimes be seen scrubbing her bloodied robe in a river and preening her long hair with a silver comb.
Have you seen this woman? Do you suspect she’s been buzzing your house? Here’s how to prove it.
Wait until night falls, then put a caged rat in your front yard (stick with me here). When you hear that banshee come screaming and rattling that cage, hit the lights. You’ll find one of the night’s most majestic creatures, the barn owl, probably looking a bit pissed off about its rudely inaccessible dinner.
This ghostly creature has gorgeously white underparts and a scream like you wouldn’t believe (have a listen below), and has for centuries served as the likely source of the banshee myth. Far from the legend, though, this is an exceedingly graceful critter whose wails echo across every continent save for Antarctica.
With each ear processing sounds quite differently, the owl’s brain analyzes the variations between the ears to pinpoint prey. It’s so effective that the owl can hunt with sound alone, homing in on rodents rummaging around in the grass below. Once it locks on, it dives and pounces with its unusually long legs—an adaptation to hunting in tall grasses.
The feathers are also highly adapted for silent flight, with extremely fine fringes that reduce turbulence, and therefore noise. The owls are positively packed with these soft, velvety feathers that help absorb sounds, far more than most birds their size (the critters are positively scrawny without their feathers on—like, hilariously so). And the intense curvature of their wings boosts lift, so the owls can cut down on the number of wing beats required to stay aloft, yet another way to reduce noises that potentially scare off prey.
Read more at Wired Science
The newly discovered tracks are from creatures called nothosaurs, the top predators of the seas during the Triassic period, which lasted from 251 million to 199 million years ago. The findings settle a long-standing debate about how the ancient sea creatures swam, said study co-author Michael Benton, a paleontologist at the University of Bristol in England.
The paddle prints were detailed today (June 11) in the journal Nature Communications.
Nothosaurs were odd-looking marine reptiles that prowled the Triassic oceans about 245 million years ago. The predators sported paddlelike forelimbs and hind limbs, long necks and tails, and long jaws filled with small, pointy teeth, Benton said.
Qi-yue Zhang, a member of the Chengdu Center of the China Geological Survey, was mapping geological features of China's Yunnan province, which is known for its stunning fossilized sea creatures, when he noticed several track marks on a ledge. The team dug up the area on the ledge and exposed 350 exquisitely preserved prints that formed about 15 different trackways, some of which looped around, Benton said.
The researchers then used photos and airborne laser scanning called lidar to map the tracks.
Next, the team compared the tracks with fossils from other animals that flourished during the same time period in that region of the world. The comparison ruled out other reptiles whose separated digits would have left imprints, as well as creatures that were too small or lacked the ability to touch the seabed with their front limbs without dragging their bellies on the bottom as well, Benton told Live Science.
That left the nothosaurs, with both the larger Nothosaurus, which could reach 13 feet (4 meters) in length, and the scrappy, 2-foot-long (0.6 m) Lariosaurus as the likely culprits.
By analyzing the tracks, the team concluded that the nothosaurs may have rowed their front limbs into the seabed, floating their bellies above so they didn't scrape the seafloor. This rowing motion would have churned up the lobsters and fish that sheltered in the soupy sediment just along the seabed, Benton said.
Read more at Discovery News
The researchers had chimps play a game in which the animals sat back to back facing computers and took turns selecting one of two blue boxes on the screen. The computer revealed each player’s choice to their opponent, and the player then had to predict what their opponent’s next selection would be based on the last choice. The chimps learned the game more quickly compared to undergraduate students who also played in a separate round.
The game was based on game theory — a field that examines how individuals devise the best strategy based on their opponents' moves in a competitive situation. It's a principle found in many aspects of daily life, from business to sports. When a soccer player decides what angle to take a penalty kick by anticipating the goalie’s response, or a person tries to negotiate a job offer with their boss, these individuals engage in game theory.
The researchers speculated that the chimps were able to play so well because they have strong short-term memory and talents for pattern recognition, and they have evolved to be highly competitive.
"Fights with other chimps and dominance hierarchies are central to their lives," said Rahul Bhui, a graduate student at the California Institute of Technology who co-authored the study.
Humans, on the other hand, have evolved to strategize and compete using language — a skill they were not able to use in this silent game, Bhui said. Communicating through language is central to how humans coordinate win-win outcomes. "We have language and widespread cooperation which (chimps) don't need to worry about, and maybe that impairs our performance in these simple competitions,” said Bhui. “Maybe these were costs we paid for other abilities."
Past research has shown that chimps have excellent short-term memories. In 2013, a Japanese researcher presented a videoof a chimp recalling the exact sequence and location of numbers that had flashed briefly on a screen.
The new findings give researchers an even better understanding of chimpanzees.
"The fact that chimpanzees track their opponents more carefully, (and) gain a competitive edge when they can, illustrates how all species can be surprisingly well adapted to challenges which are crucial for their lives, and less important for (humans)," said Colin Camerer, a behavioral economist at Caltech. "It should humble us a little."
In game theory, there is a limit to how many times a strategic game can be won based on how well a person can predict his or her opponent's move — a concept called the Nash equilibrium, named after mathematician John Forbes Nash Jr. (portrayed by Russell Crowe in the film "A Beautiful Mind"). The researchers found that the chimps were so good at the game that they came very close to hitting the theoretical limit for how many times the game can be won.
Read more at Discovery News
Normally rain is slightly acidic because CO2 dissolves into it forming weak carbonic acid. This in turn causes rock weathering, which acts as an important carbon sink. But much of the super-sized Pangea was far from the ocean and arid. The rock weathering effect was lessened, so CO2 should have risen, right? It didn't, the study reports, due to the imposing Hercynian mountain range.
"The steep slopes of these Hercynian mountains produced physical erosion," team leader Yves Godderis of the French National Centre for Scientific Research said in a release. "In a humid equatorial environment, this physical erosion promoted rock weathering and removing CO2 from the atmosphere."
The mountains ran from the Appalachians to Ireland to southwestern England through Paris, into Germany and continued east.
The researchers suggest if the mountains hadn't formed, atmospheric CO2 would have spiked sharply for a long period of time. Eventually, increased temps could have lead to more rock weathering, and a self-correction, the scientists suggest.
"There's no doubt that this would have stalled Earth's temperature at a high level for a long, long time," Godderis said. "The world would look very different today if these mountains had not developed when they did."
From Discovery News
Jun 10, 2014
The Turing Test has long been held as a landmark in machine learning. Its creator, British computer scientist Alan Turing, thought it would represent a point when computers would have brains nearly as capable as our own. But the value of the Turing Test in modern day computer science is questionable. And the actual accomplishments of the test-winning chatbot are not all that impressive.
The Turing Test 2014 competition was organized to mark the 60th anniversary of Turing’s death and included several celebrity judges, including actor Robert Llewellyn of the British sci-fi sitcom Red Dwarf. The winner was a program named Eugene Goostman, which managed to convince 10 out of 30 judges that it was a real boy. Goostman is the work of computer engineering team led by Russian Vladimir Veselov and Ukrainian Eugene Demchenko.
The program had a few built-in advantages, such as the fact that he was claimed to be a 13-year-old non-native English speaker from Ukraine. It also only tricked the judges about 30 percent of the time (an F minus, or so). For many artificial intelligence experts, this is less than exciting.
“There’s nothing in this example to be impressed by,” wrote computational cognitive scientist Joshua Tenenbaum of MIT in an email. He added that “it’s not clear that to meet that criterion you have to produce something better than a good chatbot, and have a little luck or other incidental factors on your side.”
Screenshots on the BBC’s article about the win show a transcript that doesn’t read like much more than a random sentence generator. When WIRED chatted with Goostman through his programmers’ Princeton website, the results felt something like an AIM chatbot circa 1999.
WIRED: Where are you from?
Goostman: A big Ukrainian city called Odessa on the shores of the Black Sea
WIRED: Oh, I’m from the Ukraine. Have you ever been there?
Goostman: ukraine? I’ve never there. But I do suspect that these crappy robots from the Great Robots Cabal will try to defeat this nice place too.
The version on the website could of course be a different version than was used during the competition.
This particular chatbox almost passed a version of the Turing test two years ago, fooling judges approximately 29 percent of the time.
Fooling around 30 percent of the judges also doesn’t seem like a particularly high bar. While the group claims that no previous computer program has been able to reach this level, there have been numerous chatbots, some as far back as the 1960s, which were able to fool people for at least a short while. In a 1991 competition, a bot called PC Therapist was able to get five out of 10 judges to believe it was human. More recently, there have been fears that online chatbots could trick people into falling in love with them, stealing their personal information in the process. And a 2011 demonstration had a program named Cleverbot manage a Turing Test pass rate of nearly 60 percent.
So where does this 30 percent criterion stem from? It seems to be a particular interpretation of Alan Turing’s 1950 paper where he described his eponymous test.
“I believe that in about fifty years’ time it will be possible, to programme computers… to make them play the imitation game so well that an average interrogator will not have more than 70 per cent chance of making the right identification after five minutes of questioning,” wrote Turing (.pdf).
So the father of the Turing test wasn’t using this as some threshold for intelligence, he was simply stating his prediction of where he thought computers would be five decades in the future.
For most modern-day artificial intelligence experts, the Turing Test has long since been superseded by other accomplishments. It’s not entirely surprising that a 65-year-old test doesn’t hold up, given the lack of data about intelligence — both human and artificial — available at the dawn of the computer age. Today, we have programs that show quite interesting intelligent-like behavior, such as Netflix’s suggestion algorithm, Google’s self-driving car, or Apple’s Siri personal assistant. These are all tailored to specific tasks. What Alan Turing had envisioned was a machine that was generally intelligent; it could just as easily organize your schedule as learn Latin.
Read more at Wired Science
The fully intact skeleton, possibly belonging to a 7-10 month child, was unearthed during a three week excavation at Tlachtga, on the Hill of Ward near Athboy Co. Meath.
One of Ireland’s most enigmatic sites, the Hill of Tlachtga features impressive circular earthworks which are best seen from the air. Medieval texts link the site to Samhain, the ancient Celtic Festival which is the precursor to modern Halloween.
“We may never know what caused the death of the child. The skeleton probably dates back 3,000 years and was found on the bedrock at the base of a 1.5m (3-foot, 28-inch) ditch,” lead archaeologist Stephen Davis, at University College Dublin, told the Irish Examiner.
Excavation and surveys carried out using airborne laser revealed the area was a “key ritual site.”
“The site has several different phases of monumental enclosures and we believe them to be associated with festivals and rituals potentially dating back as far as 1,000 B.C.,” Davis said.
Sitting on top of the Hill of Ward, Tlachtga is a site steeped in folklore. According to Irish mythology, it got its name from the daughter of the powerful druid Mug Ruith. According to legend, the remains of the druidess, who is said to have died on the hill after giving birth to triplets, are buried there.
Tlachtga is also believed to be the site of the Great Fire Festival in which sacrifices were offered to gods on Samhain eve. All hearth fires throughout Ireland were extinguished and then lit again from a central fire on the hill.
Meaning summer’s end, Samhain was a great festival of the dead — a time when the doorways to the otherworld opened and journeys could be made from one side to the other.
The veil between the worlds of the living and the dead was believed to be the thinnest on Oct. 31, a day which lies exactly between the autumnal equinox and the winter solstice.
The excavation revealed the monument of Tlachtga is actually the last of at least three phases of enclosure on the hill.
“As a working model for the phases of construction, at least one small enclosure, about 15 inches in diameter, was enclosed by a very large, tri- or quadrivallate enclosure, about 650 feet in diameter, which was replaced by the monument we see today,” the archaeologists said.
Read more at Discovery News
Until now, Oregon was the one state along the U.S. West Coast essentially spared from the disease. In April, researchers estimated less than 1 percent or so of the purple ochre sea stars (Pisaster ochraceus) living within 10 sites along Oregon's intertidal zones — which provide an easily accessible place to monitor sea stars — were affected by the wasting disease. By mid-May that percentage had gone up slightly, and then after that it seemed to skyrocket.
"The percentages we saw last week, they were as high as 40 to 60 percent of the population that's showing signs of wasting," said Bruce Menge, a marine biologist at Oregon State University, who is studying the wasting disease in Oregon.
Turning sea stars to goo
Sea star wasting syndrome causes a sea star's body to disintegrate, ultimately leading to death.
The disease tends to progress from no outward signs to behavior changes in which the sea stars cross their arms and seem to collapse on themselves. Then white lesions appear on the surface of the sea star's body that turn into holes; those lesions are typically followed by the disintegration of skin around the lesion and the loss of a limb or several limbs, and in extreme cases the animal's entire body is affected by the syndrome. Some of the creatures physically tear their bodies apart in the process, scientists say.
"We've seen a number of cases where all that's left is a puddle of their skeletal parts and a bunch of bacteria eating away at the tissue," Menge told Live Science. "It's a pretty gruesome thing to see."
The current outbreak of sea star wasting syndrome was first reported in June 2013 along the coast of Washington by researchers from Olympic National Park. Since that report, die-offs have been documented everywhere from California to Alaska and even along the East Coast from Maine through New Jersey.
"Wasting has been known for a long time, but usually it's very localized to a single site or single region," Menge said. When that's the case, as it was last August just north of Vancouver, British Columbia, the chances for recovery are high since the plankton, or floating forms, of the sea stars from healthy, nearby populations can recolonize those areas that were hit.
"The thing that is worrisome now is that it's happening pretty much all along the West Coast, even up into Alaska," Menge said.
In this widespread outbreak, Oregon seemed to be a lucky outlier. "We were hoping that for some weird reason we were going to miss out on it. We were optimistic," Menge said. "It finally did hit, and we really have no idea what the pathogen is, what the mode of transmission is. "
The cause of the wasting disease is unknown, though scientists working on the mystery are testing whether an underlying virus or bacteria is to blame, along with some environmental stress, such as water temperature or salt content, making the organisms more vulnerable to it.
"We are finding correlations between certain microorganisms and viruses present in the lesions," Gary Wessel, of Brown University in Rhode Island, told Live Science in an email. "We are now testing whether these organisms are causative (by infecting healthy animals and seeing if they replicate the wasting phenotype) or just associated."
Wessel added that his lab is also looking into the impacts of environmental stressors.
"In our challenge experiments to test infectivity, we are stressing the animals with salt conditions and temperature to determine if this environmental stress makes them more susceptible," Wessel said.
Since sea stars can act as keystone predators, meaning their predatory activities shape an ecosystem, their loss could have far-reaching impacts, the researchers say. By eating mussels on the low shores in Oregon, sea stars keep those populations in check so the bivalves don't explode in numbers, at the expense of other organisms. Menge said it's too early to say whether the sea stars' mussel-munching could be compensated by whelks in the area.
Read more at Discovery News
Speaking today (Tuesday) at the Goldschmidt Geochemistry Conference in Sacramento, Calif., researchers from the University of Lorraine in Nancy, France, discussed their analysis of xenon gas isotopes trapped inside South African and Australian quartz. These geological “time capsules” were formed on the primordial Earth 3.4 and 2.7 billion years ago, respectively.
The key problem with dating the early evolution of our planet is the lack of “classical geology” that we can tap into. This means that there is very little pristine material or layers of rock that has remained unchanged for billions of years. So geochemists have stepped in to use the technique of isotopic analysis to gauge the chemical conditions of early Earth.
During the formation of ancient quartz, pockets of atmospheric gases were trapped inside, freezing a chemical fingerprint of the early atmospheric conditions. By looking at the ancient ratios of xenon isotopes and comparing them with today’s, geochemists Guillaume Avice and Bernard Marty were able to precisely zero-in on the cataclysmic Earth impact that eventually formed the moon.
In the solar system’s early history, planetary collisions were common and approximately 4.5 billion years ago the Earth was hit by a hypothetical Mars-sized object — nicknamed “Theia” — unleashing huge quantities of energy, turning the planet into a searing globe of magma. The ejecta from this impact formed the moon, although the exact formation processes are not fully understood.
But through the analysis of xenon, at least we can now define when the impact occurred.
“It is not possible to give an exact date for the formation of the Earth,” said Avice in a press release. “What this work does is to show that the Earth is older than we thought, by around 60 million years.
“The composition of the gases we are looking at changes according the conditions they are found in, which of course depend on the major events in Earth’s history. The gas sealed in these quartz samples has been handed down to us in a sort of ‘time capsule.’ We are using standard methods to compute the age of the Earth, but having access to these ancient samples gives us new data, and allows us to refine the measurement.”
It was thought that the Earth’s atmosphere formed around 100 million years after the formation of the solar system. However, the primordial atmosphere would not have survived the massive Theia impact event. By studying the xenon isotope ratios from 3.4 and 2.7 billion years ago and comparing those ratios with modern Earth, Avice and Marty have been able to look back in time to find that the Earth’s atmosphere likely started to form only 40 million years after the solar system’s formation, meaning the Theia impact occurred approximately 60 million years earlier than previous estimates.
Read more at Discovery News
Jun 9, 2014
The 65 year-old iconic Turing Test was passed for the very first time by supercomputer Eugene Goostman during Turing Test 2014 held at the renowned Royal Society in London on Saturday.
'Eugene', a computer programme that simulates a 13 year old boy, was developed in Saint Petersburg, Russia. The development team includes Eugene's creator Vladimir Veselov, who was born in Russia and now lives in the United States, and Ukrainian born Eugene Demchenko who now lives in Russia.
The Turing Test is based on 20th century mathematician and code-breaker Turing's 1950 famous question and answer game, 'Can Machines Think?'. The experiment investigates whether people can detect if they are talking to machines or humans. The event is particularly poignant as it took place on the 60th anniversary of Turing's death, nearly six months after he was given a posthumous royal pardon.
If a computer is mistaken for a human more than 30% of the time during a series of five minute keyboard conversations it passes the test. No computer has ever achieved this, until now. Eugene managed to convince 33% of the human judges that it was human.
This historic event was organised by the University's School of Systems Engineering in partnership with RoboLaw, an EU-funded organisation examining the regulation of emerging robotic technologies.
Professor Kevin Warwick, a Visiting Professor at the University of Reading and Deputy Vice-Chancellor for Research at Coventry University, said: "In the field of Artificial Intelligence there is no more iconic and controversial milestone than the Turing Test, when a computer convinces a sufficient number of interrogators into believing that it is not a machine but rather is a human. It is fitting that such an important landmark has been reached at the Royal Society in London, the home of British Science and the scene of many great advances in human understanding over the centuries. This milestone will go down in history as one of the most exciting.
"Some will claim that the Test has already been passed. The words Turing Test have been applied to similar competitions around the world. However this event involved the most simultaneous comparison tests than ever before, was independently verified and, crucially, the conversations were unrestricted. A true Turing Test does not set the questions or topics prior to the conversations. We are therefore proud to declare that Alan Turing's Test was passed for the first time on Saturday.
"Of course the Test has implications for society today. Having a computer that can trick a human into thinking that someone, or even something, is a person we trust is a wake-up call to cybercrime. The Turing Test is a vital tool for combatting that threat. It is important to understand more fully how online, real-time communication of this type can influence an individual human in such a way that they are fooled into believing something is true...when in fact it is not."
Eugene was one of five supercomputers battling it for the Turing Test 2014 Prize. On winning the competition and achieving this historic milestone Vladimir Veselov said:
"I want to congratulate everyone who worked on Eugene Goostman. Our whole team is very excited with this result. It's a remarkable achievement for us and we hope it boosts interest in artificial intelligence and chatbots. Special thanks to Professor Kevin Warwick and Dr Huma Shah for their effort in organising the event.
"Eugene was 'born' in 2001. Our main idea was that he can claim that he knows anything, but his age also makes it perfectly reasonable that he doesn't know everything. We spent a lot of time developing a character with a believable personality. This year we improved the 'dialog controller' which makes the conversation far more human-like when compared to programs that just answer questions. Going forward we plan to make Eugene smarter and continue working on improving what we refer to as 'conversation logic'."
Read more at Science Daily
Their study provides the first quantitative estimate of the number of worlds in our galaxy that could harbor life above the microbial level.
"This study does not indicate that complex life exists on that many planets. We're saying that there are planetary conditions that could support it. Origin of life questions are not addressed -- only the conditions to support life," according to the paper's authors Alberto Fairén, Cornell research associate; Louis Irwin, University of Texas at El Paso (lead author); Abel Méndez, University of Puerto Rico at Arecibo; and Dirk Schulze-Makuch, Washington State University.
"Complex life doesn't mean intelligent life -- though it doesn't rule it out or even animal life -- but simply that organisms larger and more complex than microbes could exist in a number of different forms. For example, organisms that form stable food webs like those found in ecosystems on Earth," the researchers explain in an auxiliary statement.
The scientists surveyed more than 1,000 planets and used a formula that considers planet density, temperature, substrate (liquid, solid or gas), chemistry, distance from its central star and age. From this information, they developed and computed the Biological Complexity Index (BCI).
The BCI calculation revealed that 1 to 2 percent of the planets showed a BCI rating higher than Europa, a moon of Jupiter thought to have a subsurface global ocean that may harbor forms of life. With about 10 billion stars in the Milky Way galaxy, the BCI yields 100 million plausible planets.
Despite the large number of planets that could harbor complex life, the Milky Way is so vast that planets with high BCI values are very far apart, according to the scientists. One of the closest and most promising extrasolar systems, called Gliese 581, has two planets with the apparent, possible capacity to host complex biospheres. The distance from Earth to Gliese 581 is about 20 light years.
Read more at Science Daily
During that epoch of our solar system’s evolution, planetary collisions were commonplace and it is thought that a hypothetical Mars-sized body, nicknamed “Theia,” hit Earth in a cataclysmic collision some 4.5 billion years ago. The energies released during impact would have totally transformed our planet, obliterating its surface and melting its rocky mantle.
But the extent of this planetary transformation isn’t well understood. Was Earth completed melted? Or have some pockets of material of a primordial Earth persisted to modern day, proving that not all terrestrial material was affected by the Earth-Theia encounter?
“The energy released by the impact between the Earth and Theia would have been huge, certainly enough to melt the whole planet,” said geochemist Sujoy Mukhopadhyay of Harvard University and lead scientists of this research. “But we believe that the impact energy was not evenly distributed throughout the ancient Earth. This means that a major part of the impacted hemisphere would probably have been completely vaporized, but the opposite hemisphere would have been partly shielded, and would not have undergone complete melting.”
Mukhopadhyay is presenting his team’s work at the Goldschmidt geochemistry conference in Sacramento, Calif., this week.
The research focuses on the comparison of noble gas isotopes in the deep mantle compared with the shallow mantle. The Earth’s mantle is a silicate rocky shell that extends from the crust to as deep as 1,800 miles (2,900 kilometers) to the Earth’s molten outer core. The mantle is differentiated into different mineral layers that provide information about our planet’s ancient geochemical past.
The researchers analyzed ratios of isotopes of Helium (3He) and Neon (22Ne) and found that the ratio was significantly higher in the shallow mantle than it was in the deep mantle. “This implies that the last giant impact did not completely mix the mantle and there was not a whole mantle magma ocean,” said Mukhopadhyay in a press release.
In addition, they analyzed the 129-Xenon to 130-Xenon ratio from material transported from the deep mantle to the surface by mantle plumes — again, the ratio was significantly lower in material from the lower mantle when compared to ratios found at the surface. The Xenon ratio is interesting as 129-Xenon is produced by the radioactive decay of 129-Iodine, putting a definite ‘time stamp’ on the transported deep mantle material to within the first 100 million years of Earth’s early history.
“The geochemistry indicates that there are differences between the noble gas isotope ratios in different parts of the Earth, and these need to be explained,” said Mukhopadhyay. “The idea that a very disruptive collision of the Earth with another planet-sized body, the biggest event in Earth’s geological history, did not completely melt and homogenize the Earth challenges some of our notions on planet formation and the energetics of giant impacts.
“If the theory is proven correct, then we may be seeing echoes of the ancient Earth, from a time before the collision.”
In other research published in the journal Science last week, isotopic analysis of elements inside moon rock (rock recovered by the Apollo missions from the lunar surface and moon meteorites recovered on Earth) revealed the chemical signature for Theia and geologists have been able to deduce that around 50 percent of the moon is likely composed of material originating from the interplanetary impactor.
Read more at Discovery News
The study, published in the latest issue of the journal Biological Reviews, presents an alternative to the long-held theory that human faces look the way they do primarily because of a past evolved need among our ancestors to chew hard foods, like nuts.
Such ancestors likely included the australopiths, which lived 4 to 2 million years ago in Africa.
"The australopiths were characterized by a suite of traits that may have improved fighting ability, including hand proportions that allow formation of a fist; effectively turning the delicate musculoskeletal system of the hand into a club effective for striking," David Carrier, lead author of the study, said in a press release.
"If indeed the evolution of our hand proportions were associated with selection for fighting behavior you might expect the primary target, the face, to have undergone evolution to better protect it from injury when punched," added Carrier, who is a University of Utah biologist.
With that in mind, Carrier and colleague Michael Morgan, a University of Utah physician, studied both modern skulls and those of australopiths. They compared differences between males and females, and noted how facial bones respond to impacts.
The researchers found that bones that suffer the highest rates of fractures in fights are the same parts of the skull that exhibited the greatest increase in sturdiness during the evolution of our early human relatives. These bones are also the parts of the skull that show the greatest difference between males and females in both australopiths and humans today.
"In other words," Carrier said, "male and female faces are different because the parts of the skull that break in fights are bigger in males. Importantly, these facial features appear in the fossil record at approximately the same time that our ancestors evolved hand proportions that allow the formation of a fist."
He continued, "Together, these observations suggest that many of the facial features that characterize early hominins may have evolved to protect the face from injury during fighting with fists."
What were our prehistoric ancestors fighting about? Based on human behavior today and other primate behavior, it's likely that they often fought over mates, territory and other resources. They also might have just gotten on each other's nerves. After all, some were often cooped up for periods of time in caves and rock shelters.
If the latest theory holds true, then other ideas about human evolution go out the window. For example, French philosopher Rousseau argued that, before civilization, humans were noble savages and that civilization corrupted us, making us more violent.
Our distant past probably wasn't very tranquil, though.
"The hypothesis that our early ancestors were aggressive could be falsified if we found that the anatomical characters that distinguish us from other primates did not improve fighting ability," Carrier said. "What our research has been showing is that many of the anatomical characters of great apes and our ancestors, the early hominins (such as bipedal posture, the proportions of our hands and the shape of our faces) do, in fact, improve fighting performance."
Read more at Discovery News
Jun 8, 2014
"Using in situ aberration-corrected transmission electron microscopy (TEM), we found that during the oxidation reaction, cobalt atoms migrate to the nanoparticle surface, forming a cobalt oxide epitaxial film, like water on oil," says Haimei Zheng, a staff scientist in Berkeley Lab's Materials Sciences Division who led this study. "During the hydrogen reduction reaction, cobalt atoms migrate back into the bulk, leaving a monolayer of platinum on the surface. This atomic information provides an important reference point for designing and engineering better bimetallic catalysts in the future."
Bimetallic catalysts are drawing considerable attention from the chemical industry these days because in many cases they offer superior performances to their monometallic counterparts. There is also the possibility of tuning their catalytic performances to meet specific needs. A bimetallic catalyst of particular interest entails the pairing of platinum, the gold standard of monometallic catalysts, with cobalt, a lesser catalyst but one that is dramatically cheaper than platinum. The platinum/cobalt catalyst is not only considered a model system for the study of other bimetallic nanocatalysts, it is also an excellent promoter of the widely used Fischer-Tropsch process, in which mixtures of hydrogen and carbon monoxide are converted into long-chain carbons for use as fuels or in low-temperature fuel cells.
"While there have been many studies on platinum/cobalt and other bimetallic catalysts, information on how reactions proceed atomically and what the morphology looks like has been missing," Zheng says. "To acquire this information it was necessary to map the atomic structures in reactive environments in situ, which we did using specially equipped TEMs."
The in situ environmental TEM experiments were carried out at both the Environmental Molecular Sciences Laboratory, which is located at PNNL, and at BNL's Center for Functional Nanomaterials. Ex situ aberration-corrected TEM imaging was done at Berkeley Lab's National Center for Electron Microscopy using TEAM 0.5, the world's most powerful TEM.
"This work is an excellent example of collaborative team-work among multiple institutes," Zheng says. "Having access to such high-end resources and being able to form such close team collaborations strengthens our ability to tackle challenging scientific problems."
The in situ aberration corrected TEM studies of Zheng and her colleagues revealed that because of a size mismatch between the lattices of the cobalt oxide epitaxial film and the platinum surface, the cobalt oxide lattice is compressively strained at the interface to fit on the platinum lattice. As the strain energy relaxes, the cobalt oxide film starts breaking up to form distinct molecular islands on the platinum surface. This reduces the effective reaction surface area per volume and creates catalytic voids, both of which impact overall catalytic performance.
"By taking this segregation of the platinum and cobalt atoms into consideration, the interfacial strain that arises during oxidation can be predicted," Zheng says. "We can then design nanoparticle catalysts to ensure that during reactions the material with higher catalytic performance will be on surface of the nanoparticles."
Read more at Science Daily
For a long time, physicists were only able to reliably verify two different classes of hadrons: volatile mesons comprising one quark and one antiquark and baryons consisting of three quarks. Protons and neutrons, which make up atomic nuclei, are examples of the latter. In recent years, however, there has been growing evidence for the existence of additional types of hadrons, for example, hybrids, glueballs, and multiquarks. In 1964, the physicist Freeman Dyson was the first to predict such more complex states. But any reliable verification proved impossible for many years because almost no measurements could be reproduced.
Only recently, other research groups -- independently of each other -- found strong indications for short-lived, exotic particles comprising four quarks, so called "tetraquarks." The new bound state, which has now been verified at COSY, means that yet another class of exotic particles has been identified. "The new resonance that we observed confirms that quarks really do exist in six-packs. This discovery could open the door to new physical phenomena," says group spokesman Prof. Heinz Clement from the University of Tübingen.
The structure that was first discovered in 2011 is extremely short-lived and could only be detected via its decay products. The transient intermediate state -- technical term: resonance -- exists for a mere hundred-sextillionth (10 to the power of -23) of a second before it decays. This time span is so short that, for example, light can travel just a distance equivalent to the diameter of a small atomic nucleus.
Whether all six quarks form a single compact entity or rather a "hadronic molecule" has yet to be clarified. The latter would be composed of several nuclear building blocks -- for example of excited protons and neutrons bound to each other -- yet much more strongly than inside an atomic nucleus.
"The measurements that we performed at COSY in 2011 were already very precise. But because the experiments could not be repeated at any other accelerator worldwide, we had to come up with another experiment to verify the results," explains Prof. Hans Ströher, director at the Nuclear Physics Institute (IKP-2) in Jülich.
Read more at Science Daily